Malaria and Other Vector-borne Diseases Control Unit. Epidemiology and AIDS Control Department MINISTRY OF HEALTH

Transcription

1 GUIDELINES FOR MALARIA EPIDEMIC PREVENTION AND CONTROL IN ETHIOPIA Malaria and Other Vector-borne Diseases Control Unit Epidemiology and AIDS Control Department MINISTRY OF HEALTH May 1999 ADDIS ABABA

2 1 ACKNOWLEDGEMENTS This document was originally prepared by Tarekegn Abose, Desta Alamirew, Daniel Kebede, Yemane Yeebiyo, Assefaw Getachew, Asnake Kebede, Sheleme Chibsa and Melkie Tekle. The Ministry of Health appreciates the inputs of all health staff involved in the preparation of the guidelines, and the subsequent training activities towards better management of malaria epidemics in Ethiopia.

3 2 Table of Contents 1. Introduction Epidemics of malaria Malaria epidemics definition Epidemic precipitating factors Epidemic-prone areas in Ethiopia Location and major characteristics of epidemic prone areas Areas affected by seasonal epidemics Areas affected by periodic epidemics Population at risk from malaria epidemics Epidemic monitoring and surveillance system Methods of epidemic forecast and detection Level 1 using meteorological information Level 2 using entomological information Level 3 using morbidity information Epidemic prevention Epidemic preparedness Epidemic monitoring system and early detection Rapid assessment of the occurrence of epidemics and control measures Recommended epidemic for casting, prevention and control measures by strata Post-epidemic evaluation Share of responsibilities at each level Community level Health station, health posts and health centres Hospitals District health departments Malaria control sector offices Zonal health department Regional health bureaux Central (Ministry of Health) The role of other sectors in epidemic control Annex 1 Weekly malaria situation monitoring chart Annex 2 Treatment schedules 2a. Chloroquine b. Sulfadoxine pyrimethamine c. Primaquine

4 3 1. INTRODUCTION The occurrence of malaria epidemics has been more frequent and wide-spread in recent years. Although rainfall-associated breeding of the major vector Anopheles arabiensis is the main cause of seasonal malaria epidemics in Ethiopia, abnormal climatic changes have often given rise to major epidemics in the past. These epidemics have usually inflicted high incidence of mortality upon the non-immune population. Most of the epidemic-affected areas are highlands or highland fringe areas where the population lacked immunity to malaria and thus all age groups are frequently affected. The somewhat large-scale periodic epidemics have been associated with increase in temperature, abnormally high rainfall as well as unusually prolonged dry seasons. There is at present a need for a strengthened epidemic management at all levels due to the increasing problem in early detection, prevention and control. This guideline was prepared in view of this need. The general aims of these guidelines are to strengthen preparedness at all levels so that the management of epidemic outbreaks is improved and there will be better forecast, prevention, detection, and control capacity at all levels; and to increase involvement of peripheral health services in early detection of epidemics and in preventive and control measures. The occurrence of epidemics of malaria have been documented in the 1930s by Italian investigators. Ever since, numerous studies have been conducted in many parts of the country which clearly demonstrated that the transmission of the disease in the country is unstable and the population at large lacks immunity. These studies have indicated that malaria is predominantly an epidemic disease in Ethiopia, and that the generally short transmission season (due to the rainfall pattern) and the correspondingly long interval of freedom from infection results in little effective immunity acquired by the population. The most notable epidemic of malaria occurred in This was a devastating epidemic as there were an estimated three million cases out of which 150,000 people died. This epidemic is well documented by R. E. Fontaine and others (American Journal of Tropical Medicine and Hygiene, 1961, Volume 10, pp ). The epidemic covered about 100,000 square miles of highland areas between June and December The altitudinal limits of the epidemic ranged approximately between 1600 to 2150 meters elevation. According to the authors, the main precipitating causes of this epidemic, appears to have been unusual weather conditions in the highland areas of the country. Rainfall exceeded all other previous years on record, and abnormally high atmospheric temperature and relative humidity prevailed during the year. Since 1958, major epidemics of malaria occurred at intervals of approximately 5-8 years, but recently there is a trend of more frequent small- or large-scale epidemics occurring in the same or different parts of the country. Currently, there are a number of epidemic precipitating factors in addition to natural environmental or climatological factors including chloroquineresistance of falciparum malaria, high-scale population movement (due to resettlement and labor forces in agro-industrial development areas) and expansion of developmental activities such as irrigation schemes. In 1998, a large-scale and severe malaria epidemic occurred in most highlands as well as lowland areas in the country.

5 MALARIA EPIDEMICS: DEFINITION 2. EPIDEMICS OF MALARIA An epidemic (in general) is the occurrence of cases in excess of the number expected in a given place and time period. Practical problems in using this definition, in the case of malaria, include difficulty in knowing what is the "expected" in ascertaining that it has been exceeded. Endemic malaria commonly shows different kinds of variation in time: (a) season: usually determined by rainfall in tropical areas; (b) periodic: cycles of several (often 8-10) years usually determined by rainfall (and also temperature) and amplified by loss of immunity in periods of low transmission; (c) secular: long-term trends. Epidemics are "unexpected" increases superimposed on the above more or less "expected" kinds of variation. There are however some overlap between "epidemics" and the following three kinds of variation: (a) an exaggerated seasonal increase; or (b) an exaggerated "periodic" increase; or (c) an acceleration of a "secular" upward trend. These variations could all qualify as "epidemics". In non-endemic areas, any transmission (even few confirmed cases) constitutes an epidemic. Where the transmission of malaria is continual, adults develop protective immunity, whereas children suffer a great deal from the mortality and morbidity of the disease. However, in areas where the transmission of the disease is seasonal, the whole population has an equal or similar risk. Therefore, in the later case the population has a higher probability to suffer from frequent bouts of malaria out-break. Most of the malarious areas in Ethiopia are epidemic-prone. In order to detect an epidemic, first the pattern of the disease for the area concerned should be established. To do this, the health institutions data for several years should be compiled by month and year. Current data may then be compared with the compiled data. If any unusual (or significant) increase is observed it implies that there may be an epidemic. Even if there are seasonal flare-ups every year, unusual situations may be recognized if day-to-day morbidity information from health service units are carefully analyzed. In many instances, even expected seasonal increases in number of malaria cases may be regarded as epidemics depending on the level of malaria transmission. Rapid increases in the number of cases should be treated as a potentially dangerous epidemic even if the number is within the "expected" level for a specific area and time. It should be noted that a high number of malaria morbidity (which may or may not be accompanied by mortality) in an epidemic-prone area during the usual transmission season cannot be considered as "normal". Therefore, every increase in the number of malaria cases must be treated as a potentially dangerous epidemic situation and the necessary preparedness measures have to be taken for timely prevention and control EPIDEMIC PRECIPITATING FACTORS Possible precipitating factors of malaria epidemics include: a) Increase of vectorial capacity, e.g. importation of a more potent vector. b) Natural increase, mainly through abnormal rainfall (usually excess, sometimes deficit). Other natural factors may be elevation in temperature (which accelerates larval

6 5 development and hence the emergence of vector; and shortens the malaria incubation period in the vector, hence increases the fraction of infective vectors surviving that period) and humidity (which increases adult longevity). c) Man-made increase: deterioration of vector control operations, inadequate management of surface waters, insecticide resistance, destruction of cattle and/or houses (e.g. through disaster or war) leading to increased man/vector contact. d) Immigration of non-immunes into an endemic area. e) Immigration of infectives into a receptive non-endemic area. f) Resistance to antimalarial drugs. 3. EPIDEMIC-PRONE AREAS IN ETHIOPIA 3.1. LOCATION AND MAJOR CHARACTERISTICS OF EPIDEMIC-PRONE AREAS Generally, highlands or highland-fringe areas between 1000 and 2000 meters can be considered as highly epidemic-prone. Desert-fringe or semi-arid areas are also epidemic-prone. Occasionally, areas even above 2000 meters altitude (up to 2400 m) are also affected by seasonal epidemics. Only few areas in western parts of the country (areas bordering the Sudan) have relatively somewhat stable transmission of malaria (although population migration such as resettlement and labor force movement and agricultural development activities have contributed to appearance of unstable situations in these areas in recent years). Epidemic-prone areas in Ethiopia can be divided into two: areas affected by seasonal malaria epidemics and areas which are affected by occasional or sporadic epidemics Areas Affected by Seasonal Epidemics Epidemic-prone areas with lower altitudes are affected almost every year by seasonal malaria outbreaks, which are mainly associated with rainfall intensity and pattern. During most parts of the year these areas remain malaria-free or with very low transmission near water bodies. When favorable weather conditions occur during malaria seasons, transmission of the disease affects all age groups. Many of these areas are sprayed with residual insecticides once a year (and in some cases twice a year) depending on availability of the necessary resources. These spraying operations seem to prevent some of the epidemics Areas Affected by Periodic Epidemics These are areas with high altitudes (including those above 2000 meters altitude, which are normally considered as non-malarious ). During some years, when climatic conditions (especially increase in air temperature and excess or deficit rainfall) favor the transmission of the disease, severe epidemics occur in these areas. Mortality rates among affected populations are usually very high due to almost complete lack of immunity. Most of these areas are exempted from the regular residual spraying due to absence of disease (in some cases for several years); they may be sprayed during epidemics only. As it has been difficult to forecast the likelihood of malaria epidemics in these areas, occurrence of transmission are mainly detected after large areas had been affected. Also semi-arid areas with lower altitude may be occasionally affected by malaria epidemics due to availability of surface water including development areas, especially development schemes.

7 POPULATION AT RISK FROM MALARIA EPIDEMICS It is estimated that roughly two-third of the country's population are at risk of malaria epidemics. 4. EPIDEMIC MONITORING AND SURVEILLANCE SYSTEM 4.1. METHODS OF EPIDEMIC FORECAST AND DETECTION Three levels of epidemic monitoring and surveillance system have to be established. Meteorological, entomological and health-service-based morbidity information will be used for forecasting and early detection of epidemics in Levels 1 to 3, respectively. The accuracy of epidemic forecasting increases from the first level to the third, but timeliness of detection is usually compromised as one goes along the three levels. Therefore, the first level is more timely and less accurate, while the third level is more accurate but less timely. In all cases, it is recommended that all three levels must be used together (or in combinations) for effective forecasting and detection of epidemics Level 1: Using Meteorological Information Most of the major epidemics of malaria in Ethiopia have their cause in changes in meteorological conditions, such as abnormally high or low rainfall, unusually increased air temperature and humidity. As part of the plan in monitoring weather conditions, ten-daily and monthly data will be purchased from Ethiopian Meteorological Service Agency. Amount and distribution of rainfall (through space and time), mean air temperature, and relative humidity will be monitored from time to time. Rainfall Rainfall affects malaria transmission in the following ways: When there is a continuous and heavy rainfall, most water collections are disturbed and thus mosquito breeding is unlikely during the rainy period. However, as soon as the frequency and intensity of rainfall decreases, it is likely that numerous favorable mosquito-breeding sites will be created as the result. Heavy rainfall in the highlands may also cause floods in the lowlands, which creates pools of stagnant water ideal for mosquito breeding. When the number of rainy days in a specified period becomes few (and there is an intermittent rainfall which is not so high) most of the rain pools become favorable breeding sites. If the amount of rainfall is much below normal or if there is draught, water bodies such as streams and rivers will create small intermittent pools in river bed which are also favourable

8 7 for anopheline breeding. Especially when such phenomena are coupled by high air temperature, unusual epidemics may occur in highland or highland-fringe areas. Apart from creating mosquito breeding sites, rainfall also affects malaria transmission through increasing humidity, which in turn will help to increase the longevity of the adult vectors. The rainfall data which is obtained from the Ethiopian Meteorological Service Agency indicates whether the amount given for a specified period (ten-daily or monthly) is above or below the normal long-term average so that unusual situations may be recognized. The number of rainy days is also given so that continuous or intermittent rainfall can be identified. Temperature Temperature affects malaria transmission, in four major ways: First, temperature affects mosquito breeding as the length of immature stages in the life cycle depends on it. In high temperature, the egg, larval and pupal stages will be shortened so that the turn-over will be increased. This will lead to high mosquito densities within short periods of time. Secondly, temperature affects the length of the sporogonic cycle of the parasite within the mosquito host. When temperature increases, the period of the sporogonic cycle will be shortened. When there is a decrease in temperature, the development of the parasite takes long time and thus the insect would usually die before the infective (sporozoite) stage is attained. Therefore, it has been accepted that P. falciparum cannot be transmitted when the mean daily temperature is below 18 o C; likewise P. vivax transmission is usually impossible if the average daily temperature is below 16 o C. An average daily temperature of above 30 o C is lethal to the sporogonic stages of the parasite within the mosquito vector. Extremely high temperature (say above 30 o C) is also unfavorable to the vectors, as adult longevity may be reduced especially in arid environment. Nevertheless, the notions in the last two points in which it has been indicated that extremely high temperature affects malaria transmission should be interpreted with some caution. In some areas (such as Dubti and Assaita in Afar Region), the daily average temperature may exceed 30 o C but there may be still malaria transmission taking place. Although in such a situation, epidemics are unlikely, the transmission may be maintained as the result of favorable situation such as the preference of adult vectors to rest in damp and cool places that are not representative of the whole area. Humidity Humidity affects transmission by increasing the longevity of adult vectors. Usually, anophelines prefer relative humidity exceeding 60%. Interpretation of Meteorological Information In general, the various meteorological data (amount and frequency of rainfall, air temperature and humidity) should be interpreted as a whole and not separately. However, in

9 8 highland areas where the breeding places are numerous, temperature is the most important parameter to be monitored. In lowlands where the temperature is high and favorable for malaria transmission, rainfall should be monitored. In some areas (e.g. highland-fringes), all meteorological parameters may be monitored together as a whole. It will be important to establish a database including representative meteorological stations at the regional levels so that the information disseminated from time to time from the central level will be entered into and analyzed. Meteorological information may be also obtained from nearest stations as soon as collected. The analysis may incorporate developing graphs containing normal values for the period under question and deviations from these values of each meteorological factor. An early warning system should be established in each region on the basis of information obtained. This meteorological data based early warning activity will be mainly the responsibility of the regional health bureau (and to some extent the central Ministry of health) Level 2: Using Entomological Information Different entomological information will be gathered when and where possible and appropriate. Routine regular monitoring of entomological data in all epidemic-prone areas may be costly, but investigations such as monitoring the larval densities in selected areas (when there are indications for the likelihood of mosquito breeding from meteorological data) can be undertaken with minimum cost and staff. To this end, all field staff may be given practical training in simple mosquito larval collection and preservation techniques. Identification of anophelines from other larvae is simple and can be performed by all community health workers and other health staff at the periphery with minimum training. Preserved larvae may be sent to nearest laboratory where there are entomology staff for species identification. However, in the absence of species identification, action should be taken in all breeding sites where anopheline larvae have been collected. Specialized entomological staff as necessary may gather other entomological data such as resting and biting densities of adult anopheles. Usually, a high density of An. gambiae s.l. larvae and adults in an area is a very good indication that there is a likelihood of a malaria epidemic Level 3: Using Morbidity Information Health service-based data must be used to monitor the trend of morbidity. Such data are better collected at the peripheral level. Daily information collected as part of the routine health service at health stations, health centers and malaria laboratories can be extremely useful in detecting early build-up of cases. Data collected by community health agents may be also utilized. Information collected at the periphery should be interpreted frequently (e.g. weekly) by the same health unit (i.e. at the level the information is collected). Therefore, the responsibilities of detecting epidemics have to be handed over to the health service units at the periphery. Health service staff at the periphery must be given training on methods of data analysis and interpretation. In general, an epidemic of malaria may be defined as a situation when the number of malaria cases are in excess of the normal number at a specific period of time and place. Therefore the "normal" number have to be known by taking data of several years into consideration. After detection of epidemics, the situation has to be urgently reported to the higher health service levels, especially to the sector malaria office. The frequency and chains of reports and feedback will be given in the subsequent section.

10 9 Sometimes, hospital-based mortality information may be also collected for the purpose of monitoring number of malaria-specific deaths in hospitals, which may indicate the trend in mortality (although very inaccurate to represent the real situation of an area). At the peripheral health service units, the most important indicator is number of malaria cases seen during a specified period (e.g. per week) in a given number of health units. In those health service units where there are laboratory facilities, a malaria case is a patient presenting with fever whose blood sample is microscopically positive for malaria parasites. In health stations and health posts, the number of patients with fever and other signs and symptoms suggestive of malaria can be assumed as malaria cases. In malaria set offices, it is recommended that data from each health service unit must be kept separately so that it would be possible to monitor the trend of disease situation in specific areas. Unless it becomes necessary to present a summarized report, monitoring at the sector levels should involve separate files for each health service unit. In hospitals, the number of malaria-specific hospital mortality may be used together with the other indicators. Accordingly, the following indicators have to be used for early detection of epidemics: 1. Number of fever cases (diagnosed as malaria) (or clinically diagnosed malaria cases) seen at a of health service unit (without laboratory facility) during a specified period of time. E.g. 127 fever cases (diagnosed as malaria) from a health station in August Number of microscopically diagnosed malaria cases seen at a health service unit with laboratory facilities during a specified period of time. E.g. 69 microscopically confirmed malaria cases scene at a 3 health center during 1-7 July It is often better to include the proportion of Plasmodium species. 3. Other indicators: In written reports or for the purpose of in-depth analysis of data at the point of collection, it usually helps to include the following information for the specific period under question: total number of patients seen at out-patient service units total number of malaria patients seen at out-patient service units total number of admissions total number of malaria in-patients in hospitals and health centers, and total number of malaria-specific deaths among in-patients 5. EPIDEMIC PREVENTION In order to plan specific preventive measures it is essential to identify epidemic-prone areas. Highland and desert fringe areas are particularly likely to experience epidemics, especially when affected by ecological disruption. Epidemics also occur in areas of social, economic and political instability. These areas can be identified by epidemiological stratification that takes account of the transmission pattern, environmental (including meteorological) conditions, social and economic conditions, population migration patterns and other factors. In addition, close monitoring of other epidemic precipitating factors such as movement of non-immune population into malarious areas, development activities in malarious areas, and mass emergency situations would enable to identify epidemic risks.

11 10 Indoor residual insecticide spraying is the most important preventive measure. The timing of spray operation is crucial and it should be applied prior to transmission season. Monitoring of key environmental, entomological and demographic indicators will be essential for timing the spraying operations. In some cases, larval control operations may be used as prevention measures. 6. EPIDEMIC PREPAREDNESS It should be noted that the occurrence of seasonal epidemics in Ethiopia is always expected in most regions. Therefore, there should be preparedness all the time with respect to trained human resources and also antimalarial drugs and insecticides. Contingency operational funds should be allocated for malaria epidemic control in all epidemic-prone areas. As a rule, an additional 25% of the annual drug requirement should be kept as contingency. For example, if the total annual requirement of sulfadoxine-pyrimethamine (calculated from the total number of cases) is 100,000 tablets, an additional 25,000 tablets should be kept; therefore, the budget allocated for sulfadoxine-pyrimethamine must be sufficient for 100,000+25,000 or 125,000 tablets. Essential consumable contingency supplies (drugs, diagnostics supplies and insecticides) have been identified. These essential supplies for epidemic management include: 1. Chloroquine tablets 2. Chloroquine syrup 3. Sulfadoxine-pyrimethamine tablets 4. Sulfadoxine-pyrimethamine injection 5. Quinine injection 6. Quinine tablets 7. Primaquine tablets 8. Slides 9. Lancets 10. Giemsa stock solution 11. Immersion oil 12. Cotton wool 13. Alcohol, denatured 14. DDT 75% WDP 15. Malathion 50% WDP 16. Temephos 50% EC Contingency amounts should be planned for and kept in addition to regular requirements not as part of the supplies used in normal control activities. The proportion of these contingency supplies to be kept at each level has to be determined and transported to the specific levels well in advance. Availability of transportation is crucial in epidemic management. In addition to the budget required for regular activities, contingency budget must be requested and kept preferably at the regional level. Such contingency finance is for use in prevention and control of epidemics to pay mainly for daily allowances and fuel. All regions can prepare the amount of contingency supplies required at each level on the basis of the total and contingency national requirements given in Table 3. The total national requirement of regular operational funds together with contingency (excluding supplies) is estimated to be about Birr 8 million. Regions should work out their own regular and contingency financial requirement on this basis.

12 11 7. EPIDEMIC MONITORING SYSTEM AND EARLY DETECTION The disease monitoring system is not very powerful in detecting early the likelihood or occurrence of epidemics. Morbidity data are mainly used to identify areas where epidemics are occurring, but this mechanism is not efficient in detecting epidemics in their early stages due to infrequent and delayed reporting from health service units. In many malaria laboratories, the daily increase in the number of cases can be detected. In some of these laboratories, "case clustering" is undertaken to identify areas or localities which are most contributing to the increase. Some health units (especially those at the peripheral level) may report to malaria control offices the increase in the number of malaria cases (which they usually diagnose symptomatically). However, most of these health units report such phenomena only after they realize that assistance is required. The most important problem here is failure to detect early an abnormal situation, which may lead to malaria epidemics. As the result, epidemics are brought to the attention of those in the best position to control only after large number of populations or areas had been already affected. The epidemic monitoring system should be strengthened through building capacity of peripheral health service units in detecting the likelihood of epidemic situations from their basic day-to-day collection of information. An effective surveillance system should also be set up at all levels. However, emphasis should be placed on enabling the lower levels of the health service system to detect epidemics early so that timely control measures can be taken by the same level or in close cooperation with higher levels through an effective reporting system. In order to detect the occurrence of malaria epidemics as early as possible, regular monitoring of the number of malaria cases at peripheral health facilities is essential. The following steps have to be followed by each health service facility in order to detect a malaria epidemic as early as possible: 1. In each health service facility, the weekly number of malaria cases for each year during the last five years should be compiled using the following format. Region Zone Wereda Name of health facility Number of malaria cases from EC to EC (5 years) Year (EC) Hamle Nehassie Pagume Sene (6)

13 12 Largest no. of cases 2 nd largest no. of cases Among the data for the five years, determine the largest number of cases, and the 2 nd largest number of cases for each week. In the above example, For the week Hamle 1-7, the largest number of cases is 45, while the 2 nd largest number is 34. For the week 8-15 Hamle, the largest number of cases is 48, and the 2 nd largest number of cases is 40.

14 13 2. Using the above table, plot a line graph (in permanent ink) for 2 nd largest number of cases against each week number as follows: No. of cases Upper normal limit Hamle Nehassie Sene This line graph will serve as a reference for comparing data for subsequent years. The line represents the upper normal limit of number of cases seen at the health facility. 3. During subsequent years, plot (with pencil or marker with different color) the weekly number of malaria cases on the reference graph as follows: No. of cases Epidemic Upper normal limit Hamle Nehassie Sene If a weekly number of cases exceeds a point on the original reference line graph or the upper normal limit (as shown for 8-15 Nehassie in the above example), it indicates the beginning of an epidemic. After detecting the epidemic, the health worker should find out from which localities most of the cases came.

15 14 Note: 1. The above procedure works only for a reference graph plotted using data of exactly five years. The procedure is invalid for data of less than or more than 5 years. The above procedure, though simple, represents an important statistical concept that is used to detect an unusual situation. The reference line-graph plotted for the 2 nd largest number is known as the third quartile for a data incorporating 5 observations. Yearly variations below or equal to the third quartile (or in our case, the 2 nd largest number) are assumed to be normal variations. Any number greater than the 2 nd largest number is assumed to be abnormally high. 2. If the number of villages in the health station s catchment area is less than 5 then it will be better to monitor the morbidity data village by village. The reason for this is that in certain instances monitoring the morbidity data by health facility may mask the existence of an epidemic in one or more villages. This is particularly true if an unusual increase in one or more villages is accompanied a by decline in the number of cases in the one ore more of the other villages. 8. RAPID ASSESSMENT OF THE OCCURRENCE OF EPIDEMICS AND CONTROL MEASURES An epidemic or disease outbreak may be reported by different bodies outside the health sectors such as district and zonal administration councils, farmers associations, government or private development projects, non-governmental organizations, and the media. Although epidemic calls from such sources are useful in a sense that they alarm responsible bodies, sometimes the information obtained may be incomplete or inaccurate. Hence, rapid assessment of the situation is required. The principal aims of a rapid assessment in epidemics are: a) to confirm that an epidemic exists or is threatening; b) to establish the cause of the epidemic; c) to estimate its geographical distribution; d) to estimate its health impact and e) to identify local capacity to control transmission and reduce morbidity. The usual approach in epidemics has been to carry out a classical epidemiological investigation. Assessment methods in malaria epidemic situations will use surveys which are usually population based and laboratory methods. In addition, health institutions based assessment is also useful. Epidemic calls should be confirmed by sending a team from a health facility and/or a malaria control sector (and sometimes zonal) offices. The team may consist of health professionals and technicians (mainly laboratory technicians with diagnostics equipment and reagents as well as antimalarial drugs) and vector biology and control technicians. The primary objective of the team is to confirm the presence of an epidemic and to determine the possible causes. The most sensitive and specific method usually employed for confirmation of malaria epidemic is examination of blood slides collected from febrile patients. In areas where microscopic diagnosis is not feasible, malaria epidemics may be confirmed based on clear malaria-specific clinical case-definition. Clinical case definition of malaria is the presence or history of fever in the past 2-3 days, after exclusion of other major causes of fever. Some simple entomological surveys may be undertaken in order to confirm the presence of malaria vectors. Some vector control measures may also be recommended as the result of the entomological surveys. The laboratory technicians will take blood slides from febrile patients and examine on the spot, this being by far the most used confirmation

16 15 activity. Another alternative is to collect blood slides by health service units and send with the epidemic call so that confirmation by microscopic diagnosis is possible before the team sets out. Collaboration is needed with disaster prevention and preparedness workers, water resource development projects or agricultural development projects, etc. The geographical distribution of the epidemic should also be defined during rapid assessment not only from health facilities and surveys conducted at market places or main roads or towns, but also by visiting different villages, looking for new graves, asking different individuals such as religious leaders, a local political figure, government officials, non-governmental organizations in the area, etc. If there is no clear consistency in the replies, several affected areas should be included in the survey. This would enable to select the most affected villages from least-affected ones and prioritize the control measures. A detailed emergency plan of action should be rapidly (but carefully) prepared in order to optimally use available personnel, finance, transportation, supplies and time. In this plan, the responsibilities, localities to be covered, schedule of work for each control team should be shown clearly. Measures for the control of epidemics should be selected on the basis of epidemiological situations of the area, characteristics of the epidemics, and availability of resources. The epidemic control measures include mass treatment, fever treatment of all febrile cases and focal spraying of residual insecticides. Larval control activities (including source reduction and larviciding) can be also undertaken in some areas together with one or both of the above measures. The choice of type and intensity of control measures depends upon availability of resources (including manpower, drugs and other supplies, insecticides, operational funds, and means of transportation), the extent of the epidemics, as well as epidemiological information. Mass treatment is the first emergency measure in most epidemic situations. Treatment of febrile or only positive cases could also be undertaken depending on the magnitude of the epidemic and resources available. If entomological studies suggest that transmission is likely to continue, residual insecticide spraying may need to be undertaken at the same time. Larval control measures through source reduction and larviciding are also important in control of epidemics wherever they are feasible. The impact of mass treatment or selective treatment is more rapid and more important in immediately reducing the prevalence of infection and disease burden than all other control measures. However if transmission is likely to continue with the same intensity (as determined from meteorological and entomological information) drug administration should be supported by vector control aimed at reducing transmission Presence of active transmission may be proved by some entomological studies such as collection of adult and larval vectors in the area. In the presence of transmission, vector control measures including residual insecticide spraying may be taken together with treatment of febrile patients or mass drug administration (and if possible larval control measures). Where and when the extent of the epidemic is not so great and continuation of transmission is unlikely, residual spraying may be omitted, and the other measures may suffice. In the past, the use of such control measures as mass drug administration (with all their epidemiological limitations) has helped to save lives especially in remote rural areas. In such cases when the occurrence of outbreaks is the result of rain pool breeding of the vector, the impact of mass treatment constitutes a significant control measure when the transmission

17 16 is short-lived. Epidemic outbreaks, which occur in highlands during the dry season (due to the increase in temperature and formation of pools in riverbeds and streams), may require the use of residual house spraying together with mass treatment. In this case, the impact of such spraying campaigns has been clearly shown but in others, the start of the rainy season which affects most the breeding grounds in rivers (and the resultant interruption of transmission) has masked the effect of the control measures taken. In other instances, the interruption of transmission due to the natural decline in vector breeding and density has interfered with the evaluation of the impact of epidemic control measures taken. The practical significance of this phenomenon is the need for awareness of the fact that such control measures, as residual house spraying may be wastage of time and resources when the likelihood of interruption of transmission due to natural environmental factors is expected or already in place. The use of indoor residual spraying should be limited to situations where transmission is believed to continue due to favourable epidemiological factors. Once the affected localities are identified, a team should visit the area immediately. The team should carry the necessary medical supplies for treating cases. If there is a laboratory at the health facility, the team should take a sample of about 50 slides from febrile patients for the purpose of determining whether the cause of the febrile illness was malaria, and if malaria was the cause, the parasite species causing the epidemic. Make the following decisions according to the prevailing situation: If among the slide-positive cases, P. falciparum cases are more than 30% (and the rest are P. vivax cases), use sulfadoxine-pyrimethamine and primaquine for mass or fever treatment. Example: Total examined = 50 febrile patients No. Positive = 30 P. falciparum cases = 10 ; 10/40 = 33.3% (which is >30%) P. vivax cases = 20 ; 10/40 = 66.7% If among the slide-positive cases, P. falciparum cases are less than or equal to 30% (and the majority are P. vivax cases), use chloroquine for mass or fever treatment. If there is no laboratory facility to ascertain the parasite species, use sulfadoxinepyrimethamine and primaquine for mass or fever treatment. Note: Primaquine is used for its gametocytocidal activity and impact on transmission. For all dosages, please refer to Annex 2a-2c. Either mass treatment (which means giving full treatment to all people in the affected village) or fever treatment (which means giving full treatment to febrile patients only) will depend on the proportion of cases in the population. Starting from one randomly selected household in the highly affected part of the village, take 20 houses in sequence and fill the following format:

18 17 House No. Total no. of household members No. of sick household members during the last 7 days Total If the total number of sick people among the total household members in the 20 houses is greater than 30%, give mass treatment for the entire population of the locality. If this percentage is less than or equal to 30%, use fever treatment. The next step would be to establish whether the epidemic is ongoing (whether transmission of malaria is in progress) or at its final stage. This can be established by carrying out an appropriate entomological investigation in the affected village(s). If anopheline larvae are present in large numbers in breeding places, which are unlikely to dry up in few days, and if adult anophelines are found resting indoors, indoor residual spraying may be needed. If entomological investigation is not feasible, the least one can do to ascertain this is to look for mosquito breeding places around the village and inquire villagers whether the number of mosquitoes in the houses has declined/increased at night. If many breeding places are identified and/or the mosquito density is reported to be high by villagers, and if more than 30% of the household members are sick as shown above, then indoor-residual spraying may be required in addition to the mass treatment. All health service units should notify their respective district health department or heath center (in the case of health posts) the occurrence (or likelihood) of a malaria epidemic as soon as detected. The district health department has to report this the same day to the sector malaria

19 18 control office, while investigating the situation for necessity of assistance from higher levels. This chain of epidemic notification may continue up to the zonal, regional and central levels depending on the intensity of the disease situation and requirement of assistance. During the epidemic period, weekly reports and feedbacks should be sent to each level below (and up to) the zonal level. During all other (non-epidemic) periods, monthly reports on the situation of malaria should be sent from each level up to the central office (Ministry of Health).

20 19 Recommended epidemic forecasting, prevention and control measures by strata*. Strata Forecasting (indicators and sources of data) Preventive measures Early detection Control measures Temp Rainfall Larval IRS Larval density control Other measures Short transmissi on Extended transmission MT (FT) Larval control IRS Rural areas, traditional agriculture ( m) X X X Monitoring morbidity data from health services MT or FT X X if feas-ible X Rural agricultural areas ( m) X X X if evidence is strong " " X X if feas-ible X Rural agricultural areas ( m) X X " " " X X if feas-ible X Rural areas, modern irrigation ( m) Epidemic-prone semi-arid rural areas below 1000m X X in some cases X " X esp. flooding X X " " X X X " " X X X Urban areas X X in some cases X X Returnees and refugees Prophylaxis Site selection ITN Early treatment " " X X X if feasible; barrier spray " " X X X if feas-ible * Abbreviations: Temp = Temperature; IRS= Indoor residual spraying; MT= Mass treatment; FT= Fever treatment; ITN= Insecticide-treated bed nets

21 20 9. POST-EPIDEMIC EVALUATION Post-epidemic evaluation should be done at each level in order to identify problems encountered in forecast, early detection, prevention and/or control; and to undertake retrospective investigations on the possible cause of the epidemic. Such information helps to identify both the strengths and drawbacks of the epidemic management system and take corrective actions in the future. The timing and impact of intervention measures used may be evaluated in the light of available data. Information on the level of preparedness (in manpower, logistics and finance) before the epidemic occurred, actual consumption of resources in preventive and control measures, and participation of the community and other governmental and non-governmental sectors should be compiled. In post-epidemic evaluation, all sorts of data (including retrospective meteorological, entomological, morbidity and mortality data), and other administrative data (stock and financial levels before the epidemic occurred, and actual consumption), transportation, and others may be used as sources of information. 10. SHARE OF RESPONSIBILITIES AT EACH LEVEL It is important that the responsibilities of the various levels (of the health service and the community) be clearly identified so that all partners will actively participate in the effort of the prevention and control of malaria with available resources COMMUNITY LEVEL The active involvement of the community in all control activities will be very crucial. Appropriate and intensive health education should be given so that communities will participate with a sense of ownership in the program. The most important inputs from local communities are as follows: a. Selection and supporting community health workers who will provide early diagnosis and treatment of patients. b. Undertaking environmental control (source reduction activities). c. Participation in other vector control activities such as residual house spraying, especially through cooperation during spray operations and by protecting sprayed surfaces from being re-plastered. d. Participation in prevention and personal protection measures including increased use of insecticide-impregnated bed-nets, selection of settlement sites, etc.

22 21 e. Early detection of epidemics and reporting malaria situations from time to time to health service units or malaria control offices and participation in epidemic control measures. The community and village health workers have also a very important role of detecting epidemics early and reporting on time to health institutions and all other concerned parties. Wherever there are village health workers, the trend in the number of febrile patients treated as malaria cases should be monitored and abnormal situations detected as early as possible, in order to take timely actions HEALTH STATIONS, HEALTH POSTS AND HEALTH CENTRES These have very important role especially in disease management, epidemic detection and control, as well as health education to clinic attendants. In particular, the health stations have high coverage in rural areas than the other health service units; hence their involvement in epidemic detection and control is essential. The active participation and ownership of these health service units in the malaria control program in their catchment areas and their collaboration with the specialized malaria sector offices is considered important HOSPITALS The proper management of severe and complicated malaria cases in hospitals will help to reduce the incidence of mortality. Hospitals have also important roles in reporting the trend in malaria-specific mortality and morbidity (especially admissions) DISTRICT HEALTH DEPARTMENTS District health departments have a very important role of collection and analysis of data from community health workers, health stations, health centers, hospitals and other private health service units. They are responsible for the overall co-ordination of epidemic prevention and control activities in their respective districts MALARIA CONTROL SECTOR OFFICES At the moment, the sector office is the most important implementing unit of malaria control activities. All malaria control strategies and techniques planned at higher levels are useless unless they are effectively implemented at the peripheral level. The role of the sector office is very crucial in Ethiopia, and thus this particular level should be strengthened logistics and finance until the primary health care units (or health centers with their satellite health posts) can effectively take over malaria control in their catchment areas. At the moment, the sector malaria control office coordinates the overall malaria control activities in its catchment area.