Prevention and Controlă The Trustee of the Wellcome Trust 1998Reviewed by: Dr A Ashworth, Public Health Nutrition Unit, London School of Hygiene and Tropical Medicine,Dr S R A Huttly, Maternal and Child Epidemiology Unit, London School of Hygiene and Tropical Medicine and Dr W A M Cutting, Department of Child Life and Health, The University of Edinburgh, UKPicture: Breast feeding in a maternity ward. Copyright Image from J Ebrahim Memorial Trust.Image references ################ .\IMAGES\T37649.jpg Contents Click on the underlined text to jump tothat screen. Screen 3 Objectives 4Introduction 5Principles of Prevention and Control 9 Maternal and Child Health 17 Assessments 19Immunization 23 Assessment 24 Interrupting Transmission 31 Assessment 32 Case Management 37 Assessment 38Control of Epidemics 41 Tutorial Assessment 42Summary Underlined text is interactive. Click on underlined text to view extra information or to jump to another screen. A pit latrine in Lesotho. Copyright Copyright Image from John & Penny Hubley.Image references ################ .\IMAGES\T26573c.jpg Objectives At the end of this tutorial you should be able to: 1. list the interventions for prevention and control of diarrhoea in developing countries, and the basis of their selection 2. summarize how these interventions are implemented 3. describe the effects of each intervention on diarrhoea incidence and mortality, and the estimated cost-effectiveness 4. review measures to control diarrhoea epidemics Image references ################ IntroductionDiarrhoea Diarrhoea is: · an increase in the number, volume and water content of stools · a global cause of much illness and death· a major factor in childhood malnutrition This tutorial is about the prevention and control of diarrhoea in developing countries. For related tutorials. Picture: Hand washing reduces the transmission of diarrhoea. This woman in Lesotho is washing her hands after using the latrine seen in the background. Copyright Image from John & Penny Hubley. Diarrhoea morbidity and mortalityEach year there are: · approximately 3.3 million deaths due to diarrhoea, 80% in children under 2 years of age · over 1 billion episodes of diarrhoea, most in the developing world · 5 - 10 million travellers affected by diarrhoea Related tutorials Refer to the tutorial Diarrhoeal Diseases: Epidemiology.Image references ################ .\IMAGES\T26591.jpg Principles of Prevention and ControlPrinciples of Prevention and Control Image references ################ Principles of Prevention and Control - 1Interventions for the Prevention and Control of Diarrhoea Maternal and child health1 1. Promotion of breast feeding 2. Improvement of weaning practices 3. Vitamin A supplementationImmunization2 4. Vaccination against rotavirus, cholera and measlesInterrupting transmission 5. Improvement of water supply and sanitation 6. Promotion of personal and domestic hygiene Case management 7. Improvement of the treatment of diarrhoea For the footnotes. Interventions Interventions to reduce diarrhoea morbidity and mortality have been compared on the basis of their: · effectiveness · feasibility · cost-effectiveness Analysis suggests seven interventions (see table) for which there is strong evidence of high effectiveness and feasibility. How does each intervention reduce diarrhoea morbidity or mortality?EffectivenessThe effectiveness of an intervention is the extent to which it reduces diarrhoea: · incidence, ie. the number of new episodes (prevalence has also been used) · severity, ie. stool output · mortality, ie. the number of deaths from diarrhoea An intervention can reduce mortality by reducing either, or both, of the: · incidence· case fatality rateCost-effectivenessThe cost-effectiveness of an intervention is the cost per diarrhoea episode or diarrhoea death averted. In this tutorial all cost-effectiveness data are expressed in US$ at 1982 rates. FeasibilityThe feasibility of an intervention is the relative ease with which it can be implemented in a developing country.Footnotes 1.Two further interventions of interest are prevention of low birth weight and zinc supplementation. 2. Rotavirus and cholera vaccines are currently under development. How does each intervention act? Increased resistance Reduced exposure to Intervention to diarrhoea diarrhoea pathogens Breast feeding + + Improved weaning practices + + Vitamin A supplementation + - Immunization against rotavirus,+ - cholera and measles Improved water supply and sanitation - + Personal and domestic hygiene - +Prevention of low birth weight and zinc supplementation act through increased resistance to diarrhoea. Improved case management reduces diarrhoea mortality but has no significant impact on diarrhoea incidence. Image references ################ .\IMAGES\Tinywat.gif Principles of Prevention and Control - 2Implementing interventions A diarrhoea control programme selects and combines interventions according to the: · importance of diarrhoea morbidity and mortality · aetiology of diarrhoea · existing infrastructure · available resources · epidemiology of other diseases Picture: Measles immunization is among the most cost-effective interventions against childhood diarrhoea. Copyright Copyright holder unknown. Image supplied by MERLIN picture library. Diarrhoea mortalityWhere mortality from diarrhoea is high, priority should be given to reducing the case fatality rate through effective case management. Aetiology of diarrhoeaThe impact of oral rehydration treatment (ORT) on diarrhoea mortality is: · greatest where a high proportion of deaths are from acute watery diarrhoea · much lower where dysentery and persistent diarrhoea are more important causes of mortality, because these do not generally cause death from dehydration Existing infrastructureThe impact of promoting personal hygiene (eg. hand washing) is likely to be greater where a supply of safe water and sanitation is already in place. The cost-effectiveness of immunization against diarrhoea is likely to be increased where it can be incorporated into an existing vaccination schedule, such as the Expanded Programme on Immunization. Epidemiology of other diseasesSome diarrhoea interventions also reduce morbidity and mortality from other diseases and thus bring multiple benefits. For example: · measles immunization greatly reduces infant morbidity and mortality due to measles · improvements in water supply and sanitation may reduce disease due to helminths, dracunculiasis and trachoma · breast feeding reduces infant morbidity due to acute respiratory infection · effective diarrhoea case management reduces the incidence of malnutrition Image references ################ .\IMAGES\T45823.jpg Principles of Prevention and Control - 3Implementation through health promotion Several interventions require behavioural changes, which are achieved by health promotion. Health promotion methods include: · face to face communication · leaflets and posters· health promotion sessions (see picture)· radio and other mass media Messages can be promoted at: · antenatal and postnatal clinics · delivery of a baby · growth monitoring visits · ORT or nutrition clinics · health professional training courses What type of messages are used? Picture: Health workers talking with women about diarrhoea in rural Lesotho. Health promotion messages should build on local beliefs to achieve behavioural change, rather than try to impose a western scientific model. Who is health promotion aimed at?Copyright Image from John & Penny Hubley. Health promotion sessionsThese have been used to promote, for example: · correct ORT practice · how to make nutritious weaning foods · personal and domestic hygiene It is often relatively easy to change knowledge, harder to change attitudes and harder still to change practice.ORT and nutrition clinicsChildren being treated in these clinics: · have diarrhoea and/or malnutrition · may be a high risk group for diarrhoea Health promotion targeted at the mothers of these high risk children is potentially more cost-effective than that targeted at the mothers of healthy children. Training health professionals Improvement in diarrhoea case management rests partly on informing mothers but also on training of: · doctors · health workers · traditional healers · pharmacistsExamples of Target GroupsIntervention Target group for healthpromotion Breast feeding andMothers with children underweaning practice 2 years Influential family members,eg. fathers and grandmothers Personal and domesticAll the population hygiene Improved caseHealth workers, mothers andmanagement carersMessages for promotion To be effective, health promotion messages must be: · culturally relevant · feasible - constraints include: - cost - time- other resources Examples of constraints are: · better weaning may require the family spending more money on food · ORT may require the family member spending time with the sick child · changing personal hygiene may require a clean water supply Image references ################ .\IMAGES\T26841.jpg Maternal and Child HealthMaternal and Child Health Image references ################ Maternal and Child Health - 1Effect of breast feeding on the incidence of diarrhoea according to age. Data from Feachem and Koblinsky 1984. Effectiveness of breast feeding Breast feeding strongly protects infants in developing countries against: · morbidity due to diarrhoea (see graph) · severe diarrhoea · mortality due to diarrhoea Does breast feeding protect from diarrhoea beyond 12 months? WHO policy is to promote: · exclusive breast feeding for the first4 - 6 months of life · breast feeding with complementary feeding up to age 2 years Is this policy modified where HIVis prevalent? 3 2Relative risk 1 0-33-56-99-11 Age (months) Copyright Image from The Wellcome Trust modified from Feachem RG, Koblinsky M. Bull World Health Organ 1984;62:271-91.Graph The relative risks plotted in the graph compare no breast feeding with exclusive or partial breast feeding. The values are based on data from 35 studies. Relative Risk of Diarrhoea Mortality in Brazil Age Breast only Breast and bottle Bottle only< 2 months 1.0 3.1 24.7 2 - 11 months 1.0 2.5 3.5Data from Victora et al 1987. The protection from breast feeding against diarrhoea mortality is greatest in the first 2 months of life, the same pattern as is seen for diarrhoea incidence. Exclusive breast feedingExclusive breast feeding means that the infant is given no other fluids or food, such as: · water · teas · fruit juice · animal or formula milk · gruels or other complementary food Diarrhoea severityBreast feeding, especially exclusive breast feeding, protects infants from: · hospitalization for severe diarrhoea · diarrhoeal dehydrationBreast feeding after 12 monthsA few studies suggest that breast feeding between 12 and 36 months offers some protection against diarrhoea morbidity and mortality, but at a lower level than in infancy.Feeding after 4 - 6 months After 4 - 6 months of age: · exclusive breast feeding does not provide enough nutrition · weaning foods to complement breast feeding should be started See screens 13 - 14 for details of weaning practice. Policy where HIV is prevalent· Breast feeding can transmit the human immunodeficiency virus (HIV) from mother to child. A woman who knows that she is HIV positive may therefore decide to feed her baby on non-breast milk. · Where a mother’s HIV status is not known, as in the majority of the population in developing countries, the benefits of breast feeding on diarrhoea will generally outweigh the risk of HIV transmission. · This is a complex area in which WHO has recently issued new guidelines (WHO 1998). Image references ################ .\IMAGES\Brstfeed.gif Maternal and Child Health - 2Promotion of breast feeding - 1 One way in which breast feeding is promoted is by giving information and support to mothers. Advantages of breast feeding to promote are: · breast feeding helps the child to grow and stay healthy · breast milk protects the child from diarrhoea and other infections · breast milk is the ideal complete food for the first 4 - 6 months· breast feeding is convenient and cheap · breast feeding helps with birth spacing· breast feeding encourages emotional bonding between mother and baby How are these messages promoted? Picture: A health worker talking to an expectant mother. Face to face counselling of mothers about breast feeding is probably the most effective means of promotion.Copyright Image from J Ebrahim Memorial Trust. In: Diarrhoea, a major public health problem.Save the Children Fund. PromotionBreast feeding counsellors (see picture) are central to providing mothers with information and support. They should talk to mothers, and influential family members where possible, at: · antenatal clinics · delivery · postnatal clinics · home visits Other means of promotion include: · leaflets and posters · mass media campaigns · the International Code of Marketing of Breast-milk SubstitutesBirth spacingA period of infertility results if breast feeding is done: 1. starting immediately after delivery 2. exclusively up to the age of 6 months 3. frequently (on demand) 4. day and nightComplete foodYoung infants being breast fed do not need additional:· fluids, except ORS solution if they have diarrhoeal dehydration · food, until weaning is started at age 4 - 6 months Image references ################ .\IMAGES\T23801.jpg Maternal and Child Health - 3Promotion of breast feeding - 2 The other main way to promote breast feeding is changing hospital practices, for example through the ten steps of the WHO/UNICEF Baby Friendly Hospital Initiative listed opposite. How effective is the promotion of breast feeding? Baby Friendly Hospital Initiative 1. Have a written policy on breast feeding.2. Train all healthcare staff to implement the policy. 3. Inform all mothers about the benefits of breast feeding. 4. Help mothers to start breast feeding within 30 minutes of delivery. 5. Show mothers how to breast feed and maintain lactation. 6. Give newborn babies no food or drink (ie. promote exclusive breast feeding) unless medically indicated.7. Practise rooming in.8. Encourage breast feeding on demand. 9. Discourage pacifiers10. Foster the formation of breast feeding support groups. Changes to hospital practicesThese changes: · can be achieved relatively cheaply by lobbying senior hospital staff and training of health professionals · are effective only where a high proportion of deliveries are in hospital · need reinforcing regularly to take account of staff turnover · should be routinely monitored by simple checksWritten policyThis policy must be routinely communicated to all healthcare staff.Inform all mothersMothers can be informed by: · face to face counselling · leaflets · posters Exclusive breast feedingFeeding any fluid, including water, glucose-water and infant formula milk, should be discouraged. Bottle feeding: · discourages the baby from correct breast feeding · reduces the mother’s milk production Rooming inRooming in means that mothers have their babies alongside them in a cot all the time. This practice encourages: · breast feeding on demand · emotional bonding between mother and baby Feeding on demand Breast feeding on demand day and night: · helps to increase the mother’s milk production · should be continued at homeBreast feeding support groupsHospitals should promote support groups and refer mothers to them.Effectiveness of Promotion of Breast Feeding1Infant age Fall in prevalence of non-breast fed(months) infants after health promotion2 0 - 2 40% 3 - 5 30% 6 - 12 10%1. Data from Feachem (1986) estimated from 21 studies. 2. Calculated to reduce diarrhoea incidence by 8 - 20% and diarrhoea mortality by 24 - 27% in the first 6 months of life. Median cost-effectiveness estimated at US$45 per diarrhoea episode and US$1000 per diarrhoea death averted for children under 5 years. Image references ################ Maternal and Child Health - 4For picture legend. Weaning practices: food hygiene Education of mothers aims to prevent contamination of complementary foods. Hygienic practices for promotion include: · washing hands before preparing or giving food · preparing food in a clean place with clean utensils · thorough cooking or reheating of foods · using boiling water to prepare formula milk · not leaving cooked food for a long time at room temperature· feeding gruels using a clean cup and spoon How effective are these measures? Copyright Image from John & Penny Hubley. Storage at room temperatureThis recommendation applies equally to gruel (porridge) or milk for infants. If cooked food for any person must be kept for more than 2 hours before eating, it should be: · covered and kept cool · reheated thoroughly before eating if not kept in a refrigerator Feeding by cup and spoonFeeding bottles are a common source of contamination and should not be used. A cup and spoon are much easier to keep clean. Effectiveness of improved weaning practices Studies of weaning practice have in the past concentrated on its effects on malnutrition (see screen 14). Including food hygiene messages in weaning education programmes is likely to increase the cost-effectiveness of this intervention significantly. Picture legend Picture: Feeding complementary foods in Zambia. It is common in Africa to ferment weaning foods. This makes them acidic, inhibiting growth of some bacterial pathogens and possibly reducing the incidence of diarrhoea. Image references ################ .\IMAGES\T26581.jpg Maternal and Child Health - 5For picture legend. Weaning practices: nutritional statusEducation of mothers aims to prevent malnutrition by modifying weaning practices. Messages for promotion include: · introducing complementary foods between4 and 6 months of age· giving weaning food which has a highenergy and nutrient concentration· feeding frequently, eg. four or five times a day · completing weaning gradually not abruptly (see picture) How effective are these measures? Copyright Image from Cutting WAM. Effectiveness of weaning educationBetter nutritional status achieved through a weaning education programme is calculated to: · reduce diarrhoea mortality by 2 - 12% in children under 5 years· have a median cost-effectiveness of US$1070 per diarrhoea death averted These calculations exclude any effects of weaning education on food hygiene. These are likely to bring: · a significant reduction in diarrhoea incidence · further reductions in diarrhoea mortalityMalnutritionMalnutrition predisposes a child to diarrhoea of increased: · duration · severity · case fatality rate Malnutrition may predispose to an increased incidence of diarrhoea, although this is controversial.Start of weaningPicture: The ‘weanling dilemma’. Refer to the text below for details.Image from The Wellcome Trust.Too earlyToo lateDiarrhoea Malnutrition Optimal timing of weaning Introducing complementary foods too: · early (before 4 months) increases the risk of diarrhoea · late (after 6 months) increases the risk of malnutrition The nutritional effects of poor weaning practice can extend for several years, well after the child is completely weaned. Energy and nutrient contentThe first weaning foods are often starchy semisolid foods based on cereal flour or starchy roots. These are not enough by themselves because they are: · often low in energy · deficient in some nutrients These limitations can be partly overcome by adding: · a little oil or fat to increase the energy content · foods from animals · pulses · dark green leaves and orange coloured fruit and vegetablesAbrupt completion of weaningThe most common reason for a mother to stop breast feeding abruptly is that she becomes pregnant. Picture legend Picture: A young Indian girl (arrow) with marasmic kwashiorkor who was weaned abruptly when the mother became pregnant again. The more recent child is being breast fed and is healthy.Image references ################ .\IMAGES\T23661.jpg .\IMAGES\Weandilm.gif Maternal and Child Health - 6Vitamin A supplementation Prophylactic vitamin A: · reduces diarrhoea mortality in young children by at least 30% (see table) · has no significant impact on the incidence of diarrhoeaHow is this intervention implemented?Impact of Vitamin A Supplementation on Diarrhoea Mortality1 YearCountry Relative risk ofdeath from diarrhoea2 1993 Ghana Acute diarrhoea 0.66 (0.47 - 0.92)Persistent diarrhoea-malnutrition0.67 (0.38 - 1.18) 1992 Sudan 1.01 (0.68 - 1.49) 1992 Nepal (highlands) 0.65 (0.44 - 0.95) 1991 Nepal (lowlands) 0.61 1990 South India 0.48 (0.24 - 0.96) 1. Based on data summarized by Huttly et al 1997. 2. Values in brackets are 95% confidence intervals. A relative risk of 0.60 means that children given vitamin A supplements were 40% less likely to die from diarrhoea than controls not given vitamin A. Vitamin A and diarrhoea mortality The 30% reduction in mortality has been consistently found in large community based randomized controlled trials in areas where vitamin A deficiency is a recognized problem. It is thought that vitamin A supplements reduce diarrhoea mortality by reducing the severity of diarrhoea. Vitamin A supplementationChildren’s liver stores of vitamin A can be improved by: · giving vitamin A capsules, eg. 200,000 international units every 4 months · adding vitamin A to certain foods · improvements in diet, eg. more dark green leaves and orange coloured fruits and vegetables Image references ################ Maternal and Child Health - 7The feasibility and cost-effectiveness of the following interventions are being evaluated. Prevention of low birth weight Low birth weight in developing countries is associated with increased infant: · diarrhoea mortality by a factor of 2 - 3 · diarrhoea incidence by a factor of 2 - 4 · mortality from all causes by a factor of 5 - 10 How is prevention of low birth weightimplemented? Zinc supplementation Daily zinc supplementation significantly reduces the incidence of diarrhoea in young children. Picture: A low birth weight infant in Zaire.Copyright Image from The Leprosy Mission International. Preventing low birth weight Low birth weight due to IUGR could be prevented by:· reduced consumption of tobacco in pregnancy · chemoprophylaxis for malaria in endemic areas · improved nutrition in pregnancy · better antenatal care to treat maternal infections · doing less physically demanding work during late pregnancy Low birth weight Low birth weight is defined as less than 2500 g. In developing countries it is more often due to intrauterine growth retardation (IUGR) than to prematurity, ie. birth before 36 weeks of gestation.Impact of Oral Zinc Supplementation on Diarrhoea1Year Country Effect of zinc supplementation21996 India 21% lower incidence ofpersistent diarrhoea 14% lower incidence of dysentery 1996 Viet Nam 45% lower incidence of acute diarrhoea 1997 Mexico 35% lower incidence of acute diarrhoea 1997 Guatemala 22% lower incidence of acute diarrhoea 1. Based on data from Black 1998. 2. Children who received zinc versus those who did not.Image references ################ .\IMAGES\T29177.jpg Maternal and Child Health: Assessment - 1Are the following statements about breast feeding true or false?To return to the start of the section. Click on the True or False button for each statement. 1. The protective effects of breast feeding are limited to the first 6 months of life.2. Breast feeding should be promoted as clean, healthy, nutritious and cheap.3. The best method to promote breast feeding is to encourage changes in hospital routine after delivery.4. Promotion of breast feeding reduces the prevalence of non-breast feeding by up to 40%, depending on the baby’s age.Correct Text explaining the answer (11-pt plain blue) Incorrect Breast feeding reduces diarrhoea incidence and diarrhoea mortality in an age dependent manner. The effect is greatest in the first 2 months of life and lasts to at least 12 months.Incorrect Text explaining the answer (11-pt plain blue) Correct Breast feeding reduces diarrhoea incidence and diarrhoea mortality in an age dependent manner. The effect is greatest in the first 2 months of life and lasts to at least 12 months.Correct In addition, breast feeding: · can help with spacing of pregnancies · encourages bonding between mother and babyIncorrect Text explaining the answer (11-pt plain blue) Incorrect In addition, breast feeding: · can help with spacing of pregnancies · encourages bonding between mother and babyCorrect Text explaining the answer (11-pt plain blue) Correct Text 11 pt Arial dark blue goes here Incorrect Breast feeding can be promoted in this way, but this is effective only where a significant number of deliveries are in hospital. A more widely applicable means of promotion is giving information and support to mothers, eg. through breast feeding counsellors.Incorrect Text 11 pt Arial dark blue goes here Correct Breast feeding can be promoted in this way, but this is effective only where a significant number of deliveries are in hospital. A more widely applicable means of promotion is giving information and support to mothers, eg. through breast feeding counsellors.Correct Health promotion is calculated to give a fall in prevalence of non-breast feeding of: · 40% for infants aged 0 - 2 months · 30% for infants aged 3 - 5 months · 10% for infants aged 6 - 12 monthsIncorrect Text 11 pt Arial dark blue goes here Incorrect Health promotion is calculated to give a fall in prevalence of non-breast feeding of: · 40% for infants aged 0 - 2 months · 30% for infants aged 3 - 5 months · 10% for infants aged 6 - 12 monthsCorrect Text 11 pt Arial dark blue goes hereImage references ################ Which of the interventions below best matches each description? Click your mouse on an intervention box below.Hold the mouse down and drag the intervention to match its description.To return to the start of the section. Reduces diarrhoea mortality by reducing the severity of episodes.Has a huge impact on infant mortality from all causes, including diarrhoea.Prevents diarrhoea by reducing the ingestion of contaminated food and reducing malnutrition.Maternal and Child Health: Assessment - 2Improved weaning practiceVitamin A supplementationPrevention of low birth weight Yes. That's right. Yes. That's right. Yes. That's right. No. That's wrong. Try again. Well done. You have now finished this assessment.Image references ################ ImmunizationImmunization Image references ################ Immunization - 1 Rotavirus vaccines Why is a rotavirus vaccine a priority? The most advanced vaccine for rotavirus: · is an oral human-rhesus reassortant vaccine · protects young children against severe rotaviral diarrhoea · may have lower efficacy in developing than developed countries (see table) · may be incorporated into immunization programmes from 1998 How cost-effective is this vaccine?Trials of Reassortant Rotavirus Vaccine Efficacy against rotaviral diarrhoea1 YearLocation Any episode Severe diarrhoea 1995 USA2 57% 82% 1996 USA 49% 80% 1996 Peru2 20% 35 - 66% 1996 Brazil2 35% 25 - 49% 1997 Finland 66% 91% 1997 Venezuela 48% 88%For footnotes. Human-rhesus reassortant vaccineThe live vaccine contains a mixture of four viral strains which correspond to the four most common serotypes in humans. The four strains are: · a parent strain from the rhesus monkey rotavirus · three reassortant strains, each with a different viral protein 7Severe rotaviral diarrhoeaThe vaccine offers no protection against infection with rotavirus. Instead it protects against: · rotaviral diarrhoea, with moderate efficacy · severe dehydrating rotaviral diarrhoea, with greater efficacyIncorporation into immunization programmesRotavirus vaccine could be delivered in three doses within the existing WHO Expanded Programme on Immunization (EPI ). Whether the vaccine is incorporated into the EPI depends on its: · efficacy - trials in Africa and Asia are needed · cost · stability · availability · interaction with other EPI vaccines, especially poliomyelitisRotavirusWHO has made development of a vaccine against rotavirus a priority. This is because rotaviral diarrhoea: · kills 600,000 - 870,000 children each year · is unlikely to be controlled by improvements in water supply, sanitation or hygiene Cost-effectiveness of rotavirus vaccineThe cost-effectiveness of the vaccine depends heavily on whether it can be incorporated into the existing EPI. A rotavirus vaccine with 80% efficacy delivered within the EPI by age 6 months is calculated to: · reduce diarrhoea incidence by 4% and diarrhoea mortality by 13% in children under 5 years · have a median cost-effectiveness of US$5 per diarrhoea episode and US$220 per diarrhoea death avertedTable footnotes 1. Reduction in incidence in vaccinated versus unvaccinated children over 2 years. Adverse effects of vaccination were minimal. 2. A 10-fold lower vaccine dose was used in these studies.Image references ################ Immunization - 2 YearLocation Vaccine Efficacy1 19862 BangladeshWhole cell- 38-47%B subunit (ages 2 - 5 years) 63-78% (adults) 19862 Bangladesh Whole cell 24-31% (ages 2 - 5 years) 67-73% (adults) 19973 Viet NamWhole cell 68% (ages 1 - 5 years) 66% (age > 5 years)Community Trials of Oral Cholera Vaccines Cholera vaccines Two types of oral vaccine againstV. cholerae O1 have been licensed, based on: 1. killed whole cells, with or without the cholera toxin B subunit 2. live attenuated strains Versions of the killed whole cell vaccine: · protect children and adults against endemic cholera (see table)· offer no immunity to V. cholerae O139 Bengal · are unlikely to be incorporated into immunization programmes in the near future How cost-effective are these vaccines? For footnotes. Cholera toxin B subunitCholera toxin contains two subunits: · A subunit, which has a toxic A1 fragment · B subunit, which is immunogenic but not toxic Refer to the Diarrhoeal Diseases tutorials:· Organisms and Pathophysiology · Defence MechanismsLive oral cholera vaccinesSingle dose vaccines based on attenuated strains of V. cholerae O1 are: · made by deleting bacterial genes for the cholera toxin A subunit · used in some countries to protect travellers · currently being evaluated in field trials in endemic areas, eg. Indonesia Refer to the tutorial Diarrhoeal Diseases: Defence Mechanisms. Endemic versus epidemic choleraThe vaccine protects against endemic cholera. Cholera vaccines are currently not recommended for use in epidemics, such as in refugee camps. The reasons include: · the vaccine is expensive compared with other measures, eg. case management · immunity develops too slowly to offer protection · logistical problems of vaccine supply and administration to large numbers in a short timeCost-effectiveness of cholera vaccinesIn an area with relatively high rates of endemic cholera (eg. Bangladesh), an oral cholera vaccine with 70% efficacy delivered in full by age 2 years is calculated to: · reduce diarrhoea incidence by 0.2% and diarrhoea mortality by 2.8% in children under 5 years · have a median cost-effectiveness of US$174 per diarrhoea episode and US$2000 per diarrhoea death averted The relatively low cost-effectiveness of cholera vaccines is due to the: · relative rarity of cholera, even in countries where it is endemic · short duration of immunity induced by the vaccine · requirement to immunize at around 2 years (peak incidence), which prevents incorporation into the existing EPITable footnotes 1. Reduction in cholera incidence in vaccinated versus unvaccinated people. Adverse effects of vaccination were minimal. 2. Efficacy for 2 years after vaccination; efficacy after this period fell significantly. 3. Efficacy for 1 year after vaccination. Image references ################ Immunization - 3Immunization against measles Why is measles so important? Immunization with a live attenuated measles vaccine: · is an integral part of the EPI · has an efficacy of over 85% against measles · significantly reduces the: - incidence of diarrhoea - diarrhoea mortality rate How cost-effective is this measure? Picture: Vaccination for measles. Under the EPI, measles immunization in developing countries is given as a single dose at age 9 months. Note that the recommended site for intramuscular injection of the vaccine is the lateral thigh. Copyright Copyright holder unknown. Image supplied by MERLIN picture library. EPIThe WHO Expanded Programme on Immunization (EPI):· aims to reduce greatly infant morbidity and mortality from acute infectious diseases · recommends that all countries immunize against: - poliomyelitis - diphtheria - pertussis - tetanus - measles - tuberculosis (where incidence is high) - hepatitis B - yellow fever (where this is endemic) Importance of measlesMeasles is: · often accompanied by diarrhoea · a risk factor for subsequent severe or persistent diarrhoea · a major cause of death and disability in its own rightCost-effectiveness of measles immunizationThe cost-effectiveness of vaccination against measles depends heavily on the degree of coverage of the immunization programme. A vaccine with 85% efficacy against measles, delivered with 90% coverage by age 9 - 11 months is calculated to: · reduce diarrhoea incidence by 4% and diarrhoea mortality by 26% in children under 5 years · have a median cost-effectiveness of US$7 per diarrhoea episode and US$143 per diarrhoea death averted These figures exclude the much larger effects of vaccination on measles incidence and death. Measles vaccineThe measles vaccine reduces: · transmission of the measles virus · the incidence of measles · mortality due to measles Image references ################ .\IMAGES\T45823.jpg Immunization: Assessment Are the following statements about immunization true or false?To return to the start of the section. Click on the True or False button for each statement. 1. Rotavirus vaccine offers some protection against severe rotaviral diarrhoea but none against transmission of the virus. 2. Cholera vaccines are likely to be incorporated into immunization programmes in the near future.3. Measles vaccination is not a cost-effective measure against diarrhoea episodes or death.4. The main factor that determines the cost-effectiveness of immunization is the cost of the vaccine.Correct The efficacy of the rhesus-human reassortant vaccine against severe rotaviral diarrhoea is: · over 80% in several trials · possibly lower in some developing countries Incorrect Text 11 pt Arial dark blue goes here Incorrect The efficacy of the rhesus-human reassortant vaccine against severe rotaviral diarrhoea is: · over 80% in several trials · possibly lower in some developing countries Correct Text 11 pt Arial dark blue goes here Correct Text 11 pt Arial dark blue goes here Incorrect Current cholera vaccines have relatively low cost-effectiveness and are not likely to be made part of the existing EPI.Incorrect Text 11 pt Arial dark blue goes here Correct Current cholera vaccines have relatively low cost-effectiveness and are not likely to be made part of the existing EPI.Correct Text 11 pt Arial dark blue goes here Incorrect Immunization against measles is a highly cost-effective intervention against: · episodes of diarrhoea · death due to diarrhoea Incorrect Text 11 pt Arial dark blue goes here Correct Immunization against measles is a highly cost-effective intervention against: · episodes of diarrhoea · death due to diarrhoea Correct Incorrect The cost of the vaccine itself is a relatively small part of the cost of immunization. Programme costs (eg. distribution and administration of the vaccine) are usually more important.Incorrect Text explaining the answer (11-pt plain blue) Correct The cost of the vaccine itself is a relatively small part of the cost of immunization. Programme costs (eg. distribution and administration of the vaccine) are usually more important. Image references ################ Interrupting Transmission Interrupting Transmission Image references ################ Interrupting Transmission - 1Improvements in water supply Transmission of diarrhoea falls progressively as the water supply improves: · a river, pond or unprotected well · a communal tap, hand pump(see picture) or protected well· clean water piped into the home Improved water supply reduces diarrhoea incidence and mortality by: · reducing the ingestion of contaminated drinking water · facilitating personal and domestic hygiene (see screen 29) Which aspects of water supply areimportant?Transmissionof diarrhoea falling. Picture: A locally produced hand pump in Kenya. Note the sealed structure to prevent contamination of the water.Copyright Image from Furu P. Aspects of water supplyPreventing the transmission of diarrhoea requires a supply of water that is: · clean (water quality) · available in sufficient amounts (water quantity) A plentiful supply of clean water favours better personal and domestic hygiene. Image references ################ .\IMAGES\T28522.jpg Interrupting Transmission - 2 Improvements in sanitation Transmission of diarrhoea falls progressively as the level of sanitation rises: · an open hole in the groundor nearby bushes · a pit latrine (see picture) orbucket latrine · a flush or pour-flush toilet Improved sanitation reduces diarrhoea incidence and mortality by permitting hygienic disposal of faeces. This reduces contamination of: · sources of drinking water · the domestic and general environment Picture: The structure of a ventilated improved pit latrine.Flies Air currents Screen Air currents Vent Transmissionof diarrhoea falling. Pit Flies Faeces Copyright Image from The Wellcome Trust. An open hole or bushesThese sites: · do not restrict faeces · are exposed to the environment · allow contamination of drinking water Image references ################ .\IMAGES\Viplatr.gif Interrupting Transmission - 3Diarrhoea prevalence according to level of sanitation and water supply. (Incidence will show the same pattern.) Data from Esrey 1996 based on studies in eight countries.Effectiveness of water supply or sanitation Improved water supply or sanitation is associated with a median reduction of: · 20 - 25% in diarrhoea incidence · up to 65% in diarrhoea mortality Does improved water or sanitation have more impact? The impact of these interventions is generally greatest when the facilities before the intervention are poorest. Which factors affect these reductions in morbidity and mortality? Prevalence (%) 30 20 10 0 No waterIntermediateOptimum water water None Int. Opt. None Int. Opt. None Int.Opt.Level of sanitation Copyright Image from The Wellcome Trust modified from Esrey SA. Am J Epidemiol 1996;143:608-23.Reduction in incidenceThis value is based on data from over 80 studies worldwide. Water supply and sanitation have been extensively studied as an intervention.Reduction in mortalityThis value is based on data from just three studies and is therefore not very reliable.Water supply versus sanitationEarly reviews (Esrey et al 1985) found that the impact of water supply was greater than the impact of sanitation. More recent reviews (Esrey 1996) have found the opposite to be true. This issue is complex and likely to remain controversial, partly because of the variation in impact in different settings.Presence of other factorsThe impact of water supply or sanitation in different settings varies greatly. Factors known to contribute to this include the: · level of water supply or sanitation present before the intervention · type of facility being installed · patterns of breast feeding and infant nutrition · patterns of hygiene behaviour · aetiology of diarrhoea Image references ################ .\IMAGES\Diarsani.gif Interrupting Transmission - 4Cost-effectiveness of water supply and sanitation Data from over 80 studies suggest median annual costs per person of around:· US$14 for a stand-pipe and latrine in a rural area · US$46 for an in-house water supply and sewerage system It is difficult to calculate a cost-effectiveness to compare with those for other interventions. Improved water supply and sanitation bring multiple benefits, including: · lower diarrhoea rates in children and adults· reduced incidence of other infections· other benefits, eg. time saving Picture: Health promotion for improved sanitation: a nurse reading a leaflet about ventilated pit latrines.Copyright Image from John & Penny Hubley. Annual costsThese estimates include costs over the operational lifetime of a service for: · construction · operation · maintenance Children and adults The cost-effectiveness calculations for most other interventions (eg. breast feeding, immunization, weaning practice) are based on reduced diarrhoea incidence or mortality in infants or young children, ie. exclude adults. Other infectionsImprovements in water supply and sanitation may reduce the incidence of: · ascariasis - infection with roundworms · dracunculiasis - infection with guinea worms · ancylostomiasis- infection with hookworms · schistosomiasis - infection with blood flukes · trachoma - infection with the bacterium Chlamydia trachomatis A cost-effectiveness analysis based only on the impact on diarrhoea will thus seriously underestimate the benefit of these interventions. Image references ################ .\IMAGES\T26850.jpg Interrupting Transmission - 5Improvement in personal and domestic hygiene Health promotion programmes aim to encourage the following hygienic practices: · hand washing (see picture), especially: - after defaecation - after cleaning the bottoms of babies and young children - before preparing or eating food · sanitary disposal of faeces, especially those of: - babies and young children - people with diarrhoea · maintaining drinking water free fromfaecal contamination Picture: A child being taught to wash her hands; the use of soap is important. Hand washing has been linked with preventing shigellosis, which can be transmitted direct from person to person.Copyright Copyright holder unknown.Image from World Neighbours.In: Diarrhoea, a major public health problem.Save the Children Fund. Disposal of faecesEven in communities with only basic sanitation, the faeces of infants can be: 1. collected with a small shovel (a ‘dirt thrower’) 2. disposed of in a pit This helps to prevent faecal contamination of the environment.Faecal contamination of drinking waterDrinking water stored in the home can become contaminated from: · a dirty hand · a dirty utensil · contact with animals - if the source is not adequately covered Image references ################ .\IMAGES\T23793.jpg Interrupting Transmission - 6Median reduction in diarrhoea morbidity after hand washing interventions in studies worldwide.Effectiveness of improvedhygiene In 10 studies worldwide, the median reduction in diarrhoea incidence was: · 35% for hand washing (see map) · 26% for several hygiene behaviours, including hand washing Although hygiene can be promoted where water and sanitation are limited, its impact may be greatest when part of an integrated project that includes improved water supply and sanitation. How cost-effective is the promotion of personal and domestic hygiene? Myanmar: 30% USA: 48% India: 32% Bangladesh: 35% Indonesia: 89% Copyright Image from The Wellcome Trust based on data from Huttly SRA, Morris SS, Pisani V. Bull World Health Organ 1997;75:163-74. Cost-effectiveness of promoting better hygieneDepending on the method of promotion, the median cost-effectiveness of hygiene education is estimated at US$20 - 500 per childhood diarrhoea episode averted. This calculation is difficult to make because: · few studies have been performed · the impact on diarrhoea mortality is unknown · hygienic behaviour may depend on having soap, safe water or sanitationHand washingTo be effective, hand washing must be done with: · soap or a local substitute for soap, eg. ashes · enough water to rinse the hands thoroughly · a clean cloth to dry the hands Image references ################ .\IMAGES\Wrldmap.gif Interrupting Transmission: AssessmentThe effectiveness of improvements in water supply or sanitation has varied greatly in studies worldwide. Can you remember some of the reasons why the impact of these interventions varies? For the answer. Can you remember some of the reasons why the cost-effectiveness of these interventions is hard to define? For the answer.To return to the start of the section. Answer: Variation in effectivenessFactors that contribute to the variation in impact of water supply or sanitation include the: · level of water supply or sanitation present before the intervention · type of facility being installed · patterns of breast feeding and infant nutrition · patterns of hygiene behaviour · aetiology of diarrhoea Answer: Calculation of cost-effectivenessOne reason why cost-effectiveness is hard to calculate is that improved water supply and sanitation bring multiple benefits, including: · lower diarrhoea rates in children and adults · reduced incidence of other infections · other benefits Image references ################ Case Management Case ManagementImage references ################ Case Management - 1Principles of case management Effective management of a patient with diarrhoea requires: · prevention or treatment of dehydration, usually with oral fluids (see picture) · giving antimicrobials for specificenteric infections · appropriate nutritional management· treatment of associated infections or complications · avoiding antidiarrhoeal and other drugs A laboratory diagnosis is not generally needed for treatment. Are these measures always equally important?Picture: A child with some signs of dehydration should be given ORS solution, initially at an ORT clinic and then at home. Intravenous fluids should be reserved for patients with severe dehydration. How is dehydration prevented?Copyright Image from Cutting WAM. Enteric infectionsAntimicrobials should not be routinely given to patients with diarrhoea. The only enteric infections for which drug treatment is indicated are: · shigellosis· amoebic dysentery· cholera· persistent diarrhoea proven to be due to Giardia Refer to the tutorial Diarrhoeal Diseases: The Role of Diet and Drugs.Presumptive clinical diagnoses. Nutritional managementAppropriate nutrition during the episode includes: · continuing breast feeding · restarting solid food after 4 - 6 hours of ORT · defined diets and micronutrient supplementation for persistent diarrhoea Appropriate nutrition after the episode includes: · an extra meal each day for at least 2 weeks to promote catch-up growth · diets of more defined composition for persistent diarrhoeaAntidiarrhoeal and other drugsThese drugs include: · adsorbents, eg. kaolin‘Antidiarrhoeal’ · antimotility drugs, eg. loperamidedrugs. · antiemetics · purgatives Some of these may be of use in adults, but in children they: · have no proven benefit and may even be harmful · should never be given Prevention of dehydrationA child with diarrhoea but no signs of dehydration should be given extra fluids to prevent dehydration. Mothers should be taught about: · suitable ‘home available fluids’ · how much fluid to give · nutritional management · when to take the child to a health workerImportance of Treatment Measures Common cause(s)Most important aspects Clinical syndrome of deathof treatment Acute watery diarrhoea Dehydration Preventing ortreating dehydration Acute bloody diarrhoea ExtraintestinalAntibiotics for dysentery complications (eg. HUS1), Nutritional management malnutritionPersistent diarrhoea Malnutrition, Nutritional managementassociated infectionsTreatment of non-intestinal (eg. pneumonia)infections1. HUS, haemolytic-uraemic syndrome. Image references ################ .\IMAGES\T44891a.jpg Case Management - 2 Effectiveness of ORT ORT has been shown to reduce the: · mortality rate from diarrhoeal dehydration · need for intravenous rehydration How cost-effective is ORT? However, rehydration with standard ORS solution does not reduce the: · stool output· duration of diarrhoea How could ORT be made moreeffective? Estimated actual and potential benefit of ORT in reducing childhood deaths from diarrhoea worldwide. Data from WHO 1990 (annual mortality in 1993 was estimated at 3.2 million). Click on each sector of the pie chart for details. Deaths prevented by ORT Deaths potentially prevented by ORT Deaths not preventable by ORT Copyright Image from The Wellcome Trust modified from World Health Organization. Seventh Programme Report 1988-1989. Programme for Control of Diarrhoeal Diseases. Geneva: WHO, 1990.Deaths prevented by ORT ORT prevents death from diarrhoeal dehydration in more than 1 million children each year. The development and use of ORS solution over the past 25 years has: · had a huge impact on public health · been described as ‘potentially the most important medical advance of this century’Deaths prevented by ORT Deaths not potentially prevented by ORTAround 1.5 million children die each year from the effects of diarrhoea other than dehydration. These deaths, not preventable by ORT, are due to: · acute bloody diarrhoea · persistent diarrhoea This figure underlines the importance of aspects of case management other than ORT, eg. appropriate antibiotics and nutritional management. Deaths not preventable by ORT Deaths potentially prevented by ORTORT could prevent death from diarrhoeal dehydration in a further 2.5 million children each year. These preventable deaths occur largely because ORS is: · not available, especially in Africa · available but not used effectivelyDeaths potentially prevented by ORT Mortality rateIn a study of several developing countries, ORT given in a clinic on average reduced the: · diarrhoea case fatality rate by 71% · need for intravenous rehydration by a factor of 3Cost-effectiveness of ORTThe cost of locally produced ORS is low even where it is not subsidized:· US$0.07 per sachet to make 1 litre of solution · US$0.14 - US$0.21 for a course of treatment The cost-effectiveness of ORT: · reflects in part the overheads of running an ORT clinic · varies with the nature and severity of cases treated, and the quality of service delivered · is estimated at US$1000 - US$10,000 per diarrhoea death averted This cost is lower when ORT is given by family members at home.Increasing the effectiveness of ORTThe fact that standard ORS solution does not reduce stool output or the duration of diarrhoea: · reduces compliance with ORT · increases inappropriate use of antibiotics and ‘antidiarrhoeal’ drugs Two modifications of the standard solution partly overcome these problems: · cereal based ORS solution · reduced osmolarity ORS solution Refer to the tutorial Diarrhoeal Diseases: Rehydration and Early Feeding. Image references ################ .\IMAGES\Ortbenft.gif .\IMAGES\Ortbenf2.gif .\IMAGES\Ortbenf3.gif .\IMAGES\Ortbenf1.gif Case Management - 3 Promotion of ORT For more widespread and effective rehydration treatment: · ORT should be promoted at all levels of healthcare · ORS should be subject to social marketing· health workers should reinforce correct practice, especially: - continuing breast feeding during ORT - early feeding after initial rehydration - how to make ORS solution correctly (see picture) - the volume of ORS solution to give What is the current trend in ORT access and use? Picture:A mother being taught how to make ORS solution from a prepacked sachet. How should health workers promote ORT to mothers?Copyright Image from Cutting WAM. ORT access and useGraph: Global access to ORS and use of ORT. Image from The Wellcome Trust modified from World Health Organization. CDD Programme Annual Reports, 1982 - 1990. 80 60 40 20 0- Access (%) Use (%) 198419861988 1990 Year The availability of ORT is rising, but the use of ORT still lags well behind (see graph). Promoting ORT to mothersA health worker talking to a mother should: · explain that ORT does not stop diarrhoea but does greatly reduce the risk of dehydration and death · show her how to prepare and give ORS solution correctly · ask her to demonstrate what she has learnedPromotion of ORTORT should be promoted to doctors, health workers and pharmacists as: · proven to save lives · safeSocial marketing of ORSPrepacked sachets of ORS to make 1 litre of solution should be: · available over the counter at a wide range of retail outlets · aggressively distributed and marketed on a wide scaleVolume of ORS solutionIn a study in Pakistan, 19% of mothers using ORT thought that the correct dose was 1 - 2 teaspoons of ORS solution given two or three times per day. The recommended volume for a child of 6 months is 400 - 600 ml of ORS solution in the first 4 - 6 hours of rehydration. Image references ################ .\IMAGES\T45041.jpg .\IMAGES\Usefort.gif Case Management - 4 Use of drugs Poor case management in developing countries includes the prescription of: · antibiotics indiscriminately· inappropriate adsorbents and antimotility drugs Actions to promote more rational drug use include: · training of doctors, health workers, traditional healers and pharmacists · increasing public understanding that not all diarrhoea requires drugs · legislation to withdraw inappropriate preparations from the marketplace Why is the use of drugs so widespread? Use of ORS solution and drugs, including antibiotics and antidiarrhoeal agents, in children under 5 with acute diarrhoea. % 60 50 40 30 20 10 0 ORT use Drug use AfricaSouthSoutheastEasternWestern AmericaAsia Med. Pacific Copyright Image from The Wellcome Trust modified from World Health Organization. CDD Programme. Geneva: WHO, 1989.AntibioticsIn a study in Indonesia, children with diarrhoea at a health centre were given: · one or more antibiotic in 80% of cases · two or more antibiotics in 50% of cases Such indiscriminate use of antibiotics: · unnecessarily exposes people to adverse reactions · wastes scarce resources · worsens antibiotic resistance · diverts attention from appropriate treatmentAdsorbentsCommonly prescribed adsorbents are: · kaolin · attapulgite · smectite · cholestyramine These have no role in the treatment of diarrhoea in children. Refer to the tutorial Diarrhoeal Diseases: The Role of Diet and Drugs.Antimotility drugsCommonly prescribed antimotility drugs are: · loperamide· diphenoxylate-atropine · codeine These drugs can cause: · delayed elimination of pathogens· severe paralytic ileus· sedation · depressed respiration · central nervous system toxicity Antimotility drugs have no role in the treatment of diarrhoea in children, although they may be of value in some adults with acute watery diarrhoea.Use of drugsIn surveys in developing countries, children were given: · unnecessary or ineffective drugs in 48% of cases, much more often than they were given ORT · an average of four drugs per diarrhoea episode The use of drugs in preference to ORT partly reflects: · widespread availability of antibiotics · mothers demanding medicine to stop the diarrhoea (which ORT does not) · pharmacists selling the more expensive product Image references ################ .\IMAGES\Druguse.gif Case Management: AssessmentAre the following statements about diarrhoea case management true or false? More effective case management: Click on the True or False button for each statement. To return to the start of the section. 1. targets mothers as a key group for health promotion2. is aided by the fact that ORT reduces the duration of diarrhoea3. includes appropriate nutritional management during diarrhoea episodes4. requires more rational prescription of drugsCorrect Education of mothers aims to promote: · prevention of diarrhoeal dehydration with home available fluids · how to make and give ORS solution correctly · appropriate feeding during and after diarrhoea · when to take the child to a health worker · recognition that most children with diarrhoea do not need drugsIncorrect Text 11 pt Arial dark blue goes here Incorrect Education of mothers aims to promote: · prevention of diarrhoeal dehydration with home available fluids · how to make and give ORS solution correctly · appropriate feeding during and after diarrhoea · when to take the child to a health worker · recognition that most children with diarrhoea do not need drugsCorrect Text 11 pt Arial dark blue goes here Correct Text 11 pt Arial dark blue goes here Incorrect Standard ORS solution does not reduce the duration of diarrhoea or stool output. This leads to: · reduced compliance with ORT · inappropriate use of antibiotics and antidiarrhoeal drugs Incorrect Text 11 pt Arial dark blue goes here Correct Standard ORS solution does not reduce the duration of diarrhoea or stool output. This leads to: · reduced compliance with ORT · inappropriate use of antibiotics and antidiarrhoeal drugs Correct Appropriate nutrition during the episode includes: · continuing breast feeding · restarting solid food after 4 - 6 hours of ORT · defined diets and micronutrient supplementation for persistent diarrhoeaIncorrect Text explaining the answer (11-pt plain blue) Incorrect Appropriate nutrition during the episode includes: · continuing breast feeding · restarting solid food after 4 - 6 hours of ORT · defined diets and micronutrient supplementation for persistent diarrhoeaCorrect Text explaining the answer (11-pt plain blue) Correct Poor use of drugs includes the prescription of: · antibiotics indiscriminately · antidiarrhoeal agents such as kaolin and loperamideIncorrect Text 11 pt Arial dark blue goes here Incorrect Poor use of drugs includes the prescription of: · antibiotics indiscriminately · antidiarrhoeal agents such as kaolin and loperamideCorrect Text 11 pt Arial dark blue goes hereImage references ################ Control of EpidemicsControl of Epidemics Image references ################ Control of Epidemics - 1Preparation and early response Control of diarrhoea epidemics in developing countries requires being prepared and mounting an effective early response. These are achieved by: · establishing a coordinating committee · continuous surveillance and reporting · access to a reference laboratory · training staff to an agreed treatment policy · stocking up on essential suppliesPicture: A patient with cholera, which is one of the two most important causes of epidemic diarrhoea.Do you know what other pathogens cause diarrhoea epidemics in developingcountries?Copyright Image from Cutting WAM. Coordinating committeeThe role of the committee is to plan and coordinate the response to outbreaks. Members should: · make a comprehensive plan of preparation for epidemics · coordinate the efforts of governmental and other organizations · collect and report information on cases and deaths · organize training · arrange buying, storage and distribution of essential supplies · implement, supervise, monitor and evaluate control activitiesSurveillanceTreatment facilities should: · continuously record details of cases, including: - clinical diagnosis - treatment - outcome · review their records regularly (eg. weekly) to detect an epidemic early · notify the nearest referral facility when an outbreak is detected Reference laboratoryAt least one well equipped laboratory to which specimens can be transported must be available. The role of this reference laboratory during the epidemic is to: · identify the suspected pathogen when the epidemic is first reported · determine the antimicrobial sensitivity of pathogens · monitor antimicrobial sensitivity to detect developing resistanceEssential suppliesHealth facilities must have access to essential supplies, such as: · appropriate antibiotics · ORS · intravenous fluids · disinfectants During an epidemic these supplies will be needed quickly and in much greater quantities than normal.Other causes of epidemicsThe other significant cause of epidemic diarrhoea is Shigella dysenteriae type 1. This bacterium leads to bacillary dysentery. Image references ################ .\IMAGES\T44898.jpg Control of Epidemics - 2Preventing the spread of an epidemic Key actions to limit the extent of an epidemic include: · effective and rapid case management· health promotion· provision of safe water and sanitation· sanitary disposal of: - faeces and vomit - dead bodies · disinfection of patients’ bedding, clothes and the immediate environment Which measures are not effective? Picture: A Cambodian child with malnutrition in a Thai refugee camp. Refugee camps have been associated with high mortality rates due to diarrhoea and other diseases.Copyright Image from Centers for Disease Control and Prevention. Effective case managementIn recent cholera epidemics in Peru-Latin America and Zaire, the case fatality rate was: · 25 - 50% for patients given no treatment · 1 - 3% for patients given effective rehydration and antibioticsSafe water and sanitationDrinking water can be made safe by: · chlorination - either at source or in the home · boiling for 60 seconds Faeces can be disposed of safely in an emergency situation by: · defaecation in designated areas for burial · rapid construction of an emergency pit latrineHealth promotionMessages should focus on: · ORT and when to take a patient to the treatment centre · drinking safe water · personal hygiene · sanitary disposal of faeces · food hygieneIneffective measuresMeasures which are not effective in the control of diarrhoea epidemics include: · mass chemoprophylaxis · vaccination against diarrhoea · restrictions on travel or trade, eg. a cordon sanitaire Image references ################ .\IMAGES\T33711.jpg Which of the preventative measures below best matches each description? Click your mouse on an intervention box below.Hold the mouse down and drag the intervention to match its description.To return to the start of the tutorial. Reduces exposure to diarrhoea pathogens and improves nutritional status. Has multiple impacts on several diseases of adults and children. Achieved by targeting children at the age of 9 months. Has greatest effect in children aged less than2 months. Tutorial AssessmentImproved weaning practice Measles immunization Promotion of breast feeding Improved water supply and sanitation Yes. That's right. Yes. That's right. Yes. That's right. Yes. That's right. No. That's wrong. Try again. Well done. You have now finished this assessment.Image references ################ Summary Click on the buttons below for summary information. Picture: Breast feeding in rural Lesotho. (The baby is not yet properly attached to the breast.)Principles of Prevention and Control Maternal and Child HealthImmunization Interrupting Transmission Case ManagementControl of EpidemicsCopyright Image from John & Penny Hubley. Principles of Prevention and Control Interventions are selected on the basis of their: · effectiveness · feasibility · cost-effectiveness A control programme should combine interventions according to the: · diarrhoea morbidity and mortality · aetiology of diarrhoea · existing infrastructure · available resources · epidemiology of other diseases Health promotion has a central role in the implementation of many interventions. Maternal and Child HealthBreast feeding: · greatly reduces diarrhoea incidence, severity and mortality in infants · should be exclusive for the first 4 - 6 months and complemented up to 2 years · is promoted by: - giving information and support to mothers - changes in hospital maternity ward routine Improved weaning practices: · could reduce diarrhoea incidence and mortality through better food hygiene · reduce malnutrition, and hence diarrhoea mortality, through better nutrition Vitamin A supplementation: · reduces diarrhoea mortality in young children by at least 30% · can be achieved by giving vitamin A capsules every 4 months ImmunizationA rhesus-human rotavirus vaccine which is under development: · reduces the incidence of severe rotaviral diarrhoea · may become part of the EPI in some countries in the near future Killed whole cell cholera vaccines which are under development: · are less cost-effective than the rotavirus vaccine · are unlikely to be incorporated into the EPI Measles immunization: · is highly cost-effective against diarrhoea incidence and mortality · is an integral part of the EPIInterrupting TransmissionImproved water supply and sanitation is: · associated with significant reductions in diarrhoea incidence and mortality · expensive but brings multiple benefits Improved personal and domestic hygiene includes: · hand washing · sanitary disposal of faeces· keeping drinking water uncontaminated Case ManagementPromotion of more effective case management requires: · better management of dehydration, by: - education about ORT - promotion of ORS · more appropriate nutritional management · more rational use of drugs, by: - training of healthcare professionals - public education - legislation Control of EpidemicsPreparation for diarrhoea epidemics requires: · establishing a coordinating committee · continuous surveillance · a reference laboratory· training staff · stocking up on essential supplies Limiting the extent of an epidemic requires: · effective and rapid case management · health promotion · provision of safe water and sanitation · sanitary disposal of faeces and dead bodies · disinfection of patients’ bedding and clothesSection 1 Section 2 Section 3 Section 4 jpg image goes here Copyright Copyright Image from ....... (copyright info) (10 point Arial, blue) Section 1 Pop-up text is in blue with a yellow title in 10 pt bold left aligned.The pop up is a display icon within the library, and if the text is too long then a scroll bar should be used, pop-up boxes can be larger. Section 2 Pop-up text is in blue with a yellow title in 10 pt bold left aligned.The pop up is a display icon within the library, and if the text is too long then a scroll bar should be used, pop-up boxes can be larger. Section 3 Pop-up text is in blue with a yellow title in 10 pt bold left aligned.The pop up is a display icon within the library, and if the text is too long then a scroll bar should be used, pop-up boxes can be larger. Section 4 Pop-up text is in blue with a yellow title in 10 pt bold left aligned.The pop up is a display icon within the library, and if the text is too long then a scroll bar should be used, pop-up boxes can be larger.Image references ################ .\IMAGES\T26858.jpg You have now finished the tutorial Prevention and Controlă The Trustee of the Wellcome Trust, 1998 Further reading Further activities Restart tutorial Picture: Personal hygiene - a child being taught to wash his hands. Copyright Copyright holder unknown.Image supplied by Rahaman M.In: Diarrhoea a major public health problem.Save the Children Fund. Further reading Ashworth A. Nutrition interventions to reduce diarrhoea morbidity and mortality. Proc Nutrition Soc 1998;57:167-74. Feachem RG. Preventing diarrhoea: what are the policy options? Health Policy and Planning 1986;1:109-17. Feachem RG, Hogan RC, Merson MH. Diarrhoeal disease control: reviews of potential interventions. Bull World Health Organ 1983;61:637-40. Huttly SRA, Morris SS, Pisani V. Prevention of diarrhoea in young children in developing countries. Bull World Health Organ 1997;75:163-74. Martines J, Phillips M, Feachem RG. Diarrhoeal diseases. In: Jamison DT, Mosley WH, Measham AR, Bobadilla JL. Disease control priorities in developing countries. Oxford: OUP, 1993:91-115.Further activities To look at pictures related to this tutorial, search the image collection using the following keywords: · prevention/control · epidemiology Image references ################ .\IMAGES\T23794.jpg