Active Case Detection for Malaria Elimination
The national malaria control programmes of 14 APMEN countries were invited to participate in the ACD survey, of which 13 responded to the survey. Some countries responded to all questions and some failed to respond to certain questions or entire components of the survey.
Table 1 describes the participating countries and their respective nationally reported cases from 2010 and the country's total population. Each country's annual parasite index (API), or the number of reported malaria cases per 1,000 risk population per year, was reported by country programmes in the survey. Most respondent programmes (eight of ten) in the survey described case investigation and RACD practices that programmes aim to conduct universally throughout the country. Two respondents, Solomon Islands and Vanuatu, reported that they conduct the activities described in the survey only in designated malaria elimination provinces. The Solomon Islands has a goal of eliminating malaria from Temotu and Isabel Provinces by 2014. Tafea Province in Vanuatu is targeted for elimination by 2014.
Of the 12 countries that responded to the questions on protocols and reporting, most (nine) have developed a SOP for case investigation and/or additional screening in the community, and ten of 12 use a written case investigation report form when conducting investigations.
Thirteen of the respondents reported that they conduct case investigation as part of their surveillance activities. Over half (seven of 13) respondents reported that they conduct case investigation for all cases. Three investigate between 26 to 99% of cases, and three reported conducting case investigation for up to 25% of all cases. The survey did not ask for information on what occurs for cases that are not investigated. The event that triggers a case investigation was described by 11 of 13 countries as a case reported to either the national or peripheral level. For one of the two remaining countries, case investigation is triggered when there are "multiple cases from one village, or an individual case reported from an area typically without malaria." The second country did not respond to this question.
Over half (seven of 13) of countries reported that case investigation begins between one to two days after a case is reported, while five countries have a time period of three to seven days and one country has no defined time period.
All countries (13) reported that there is a specific person in the malaria control programme who is tasked with conducting case investigation. Nearly all programmes (11) reported that these officers are trained in case investigation techniques, and 11 countries reported that personnel conducting investigations are periodically supervised by managers. This supervision ranges from each investigation, on a quarterly basis, once per year, or on an irregular basis.
During case investigation there are several actions taken and types of information collected from the index case (Table 2). Nearly all countries (12) visit the index case, supervise treatment (12), follow up on adherence to treatment (ten), check on malaria prevention measures used by the index case (12), and educate the index case on malaria risk factors and prevention (ten). Most programmes map the location of the index case (nine), and five of these countries use geographical information system (GIS) to make the maps.
All respondents (13) reported that their programme collects information from the index case on travel history, with the majority of respondents collecting information on travel within (11) or outside (12) the district of residence, or outside of the country (13) (Table 2). Nine programmes participating in the survey collect information on whether the index case has had any recent contact with travellers or immigrants. Only three countries gather patient history of glucose-6-phosphate dehydrogenase (G6PD) deficiency, an inherited blood disorder prevalent in many malaria-endemic areas.
Out of the 13 respondents, nine countries defined imported cases as those originating in another country. The remaining countries, including the countries that have subnational elimination goals, reported importation as those infections occurring within the country but from a different province, district or other administrative unit. Ten countries collected data and reported on this type of intra-country importation (e g, from different districts). Table 3 describes the type of information that is taken into consideration when determining an imported case.
When asked whether programmes conduct RACD, 12 of 13 countries conduct this type of screening. Survey respondents reported that RACD was triggered in three different ways, and some country programmes reported several triggers for their programme: for eight countries, every indigenous case is a trigger (e g, one case identified through passive case detection considered to be local); all imported cases irrespective of duration of stay are a trigger for five countries; and one country conducts screening around imported cases if they have stayed more than a certain number of days in country (range of one to 30 days).
Table 4 depicts the threshold number of infections, identified through passive case detection that triggers RACD in individual countries, regardless of whether the case is imported or local. Other triggers for additional screening include: if there is a need to measure the API in a given area, if a person with symptoms or a positive test result occurs among travellers with whom the index case is identified, or if there is an unusual increase in cases in a community in a particular time interval, indicating a possible outbreak.
Populations targeted for RACD vary across the surveyed countries. Five countries reported conducting screening of only symptomatic people within the household of the index case, while six countries screen all (both symptomatic and asymptomatic) household members. Regarding the screening of neighbours of the index case household, five countries reported that they conduct screening of symptomatic neighbours in addition to the household of the index case while six countries screen both symptomatic and asymptomatic neighbours. Four respondents reported screening symptomatic people within a certain political boundary, while two screen all people within a political boundary. Five countries reported screening asymptomatic people during reactive case detection and two countries reported screening only symptomatic people. The radius screened from the index household for all countries ranged from 0.5 to 2.5 km.
When conducting RACD, several methods of diagnosis are used and some are used in combination with others for diagnosis confirmation and speciation (results not mutually exclusive). All (13) respondents reported using microscopy, seven use rapid diagnostic tests (RDT), five use polymerase chain reaction (PCR), two use clinical diagnosis, and one uses serology (Table 5).
During RACD, survey respondents collect information across two different groups: those screened that have a positive test or all persons screened whether or not they have a positive test. General results indicate that there is a variety of information collected, whether in positives or in all screened. See Table 6 for details about the countries that collect information for both groups. Out of 12 respondents, ten programmes collect information on the length of time spent at the current residence. All countries (the 13 survey participants) collect data on occupation during screening and nine collect information on their place of work. Eleven countries of 13 collect information on the travel history to malaria-endemic areas, and nine countries of 12 collect information on recent contact with travellers or immigrants. Three countries of 12 ask about history of G6PD deficiency. Ten countries of 13 map the residences of either the positive cases or of all those that are screened.
As part of case investigation practices, country programmes implement several types of activities, including vector control, entomological surveillance, or health education. Of the ten respondents who completed this section of the survey, all reported conducting indoor residual spraying (IRS) and a form of health education and behaviour change (information, education communication (IEC) or behaviour change communication (BCC)) as part of the response measures during case investigation or RACD. Six of the eight respondents who answered these questions reported distribution of insecticide-treated bed nets (ITNs) or long-lasting insecticide-treated bed nets (LLINs) as part of these practices. Nine of 11 countries which answered this question use some form of larval control measures as part of a case investigation process. Twelve respondents reported conducting entomological surveillance as part of investigation procedures, three of which do so in all cases. Lastly, targeted mass drug administration (MDA) is conducted as part of case investigation by one country (out of 12 respondents).
Results
The national malaria control programmes of 14 APMEN countries were invited to participate in the ACD survey, of which 13 responded to the survey. Some countries responded to all questions and some failed to respond to certain questions or entire components of the survey.
Table 1 describes the participating countries and their respective nationally reported cases from 2010 and the country's total population. Each country's annual parasite index (API), or the number of reported malaria cases per 1,000 risk population per year, was reported by country programmes in the survey. Most respondent programmes (eight of ten) in the survey described case investigation and RACD practices that programmes aim to conduct universally throughout the country. Two respondents, Solomon Islands and Vanuatu, reported that they conduct the activities described in the survey only in designated malaria elimination provinces. The Solomon Islands has a goal of eliminating malaria from Temotu and Isabel Provinces by 2014. Tafea Province in Vanuatu is targeted for elimination by 2014.
Protocols and Reporting
Of the 12 countries that responded to the questions on protocols and reporting, most (nine) have developed a SOP for case investigation and/or additional screening in the community, and ten of 12 use a written case investigation report form when conducting investigations.
Case Investigation
Thirteen of the respondents reported that they conduct case investigation as part of their surveillance activities. Over half (seven of 13) respondents reported that they conduct case investigation for all cases. Three investigate between 26 to 99% of cases, and three reported conducting case investigation for up to 25% of all cases. The survey did not ask for information on what occurs for cases that are not investigated. The event that triggers a case investigation was described by 11 of 13 countries as a case reported to either the national or peripheral level. For one of the two remaining countries, case investigation is triggered when there are "multiple cases from one village, or an individual case reported from an area typically without malaria." The second country did not respond to this question.
Over half (seven of 13) of countries reported that case investigation begins between one to two days after a case is reported, while five countries have a time period of three to seven days and one country has no defined time period.
Personnel and Supervision
All countries (13) reported that there is a specific person in the malaria control programme who is tasked with conducting case investigation. Nearly all programmes (11) reported that these officers are trained in case investigation techniques, and 11 countries reported that personnel conducting investigations are periodically supervised by managers. This supervision ranges from each investigation, on a quarterly basis, once per year, or on an irregular basis.
Activities Conducted and Information Collected
During case investigation there are several actions taken and types of information collected from the index case (Table 2). Nearly all countries (12) visit the index case, supervise treatment (12), follow up on adherence to treatment (ten), check on malaria prevention measures used by the index case (12), and educate the index case on malaria risk factors and prevention (ten). Most programmes map the location of the index case (nine), and five of these countries use geographical information system (GIS) to make the maps.
All respondents (13) reported that their programme collects information from the index case on travel history, with the majority of respondents collecting information on travel within (11) or outside (12) the district of residence, or outside of the country (13) (Table 2). Nine programmes participating in the survey collect information on whether the index case has had any recent contact with travellers or immigrants. Only three countries gather patient history of glucose-6-phosphate dehydrogenase (G6PD) deficiency, an inherited blood disorder prevalent in many malaria-endemic areas.
Determination of a Case as Imported or Indigenous
Out of the 13 respondents, nine countries defined imported cases as those originating in another country. The remaining countries, including the countries that have subnational elimination goals, reported importation as those infections occurring within the country but from a different province, district or other administrative unit. Ten countries collected data and reported on this type of intra-country importation (e g, from different districts). Table 3 describes the type of information that is taken into consideration when determining an imported case.
Reactive Case Detection
When asked whether programmes conduct RACD, 12 of 13 countries conduct this type of screening. Survey respondents reported that RACD was triggered in three different ways, and some country programmes reported several triggers for their programme: for eight countries, every indigenous case is a trigger (e g, one case identified through passive case detection considered to be local); all imported cases irrespective of duration of stay are a trigger for five countries; and one country conducts screening around imported cases if they have stayed more than a certain number of days in country (range of one to 30 days).
Table 4 depicts the threshold number of infections, identified through passive case detection that triggers RACD in individual countries, regardless of whether the case is imported or local. Other triggers for additional screening include: if there is a need to measure the API in a given area, if a person with symptoms or a positive test result occurs among travellers with whom the index case is identified, or if there is an unusual increase in cases in a community in a particular time interval, indicating a possible outbreak.
Populations targeted for RACD vary across the surveyed countries. Five countries reported conducting screening of only symptomatic people within the household of the index case, while six countries screen all (both symptomatic and asymptomatic) household members. Regarding the screening of neighbours of the index case household, five countries reported that they conduct screening of symptomatic neighbours in addition to the household of the index case while six countries screen both symptomatic and asymptomatic neighbours. Four respondents reported screening symptomatic people within a certain political boundary, while two screen all people within a political boundary. Five countries reported screening asymptomatic people during reactive case detection and two countries reported screening only symptomatic people. The radius screened from the index household for all countries ranged from 0.5 to 2.5 km.
When conducting RACD, several methods of diagnosis are used and some are used in combination with others for diagnosis confirmation and speciation (results not mutually exclusive). All (13) respondents reported using microscopy, seven use rapid diagnostic tests (RDT), five use polymerase chain reaction (PCR), two use clinical diagnosis, and one uses serology (Table 5).
Epidemiological Information Collected During Reactive Case Detection
During RACD, survey respondents collect information across two different groups: those screened that have a positive test or all persons screened whether or not they have a positive test. General results indicate that there is a variety of information collected, whether in positives or in all screened. See Table 6 for details about the countries that collect information for both groups. Out of 12 respondents, ten programmes collect information on the length of time spent at the current residence. All countries (the 13 survey participants) collect data on occupation during screening and nine collect information on their place of work. Eleven countries of 13 collect information on the travel history to malaria-endemic areas, and nine countries of 12 collect information on recent contact with travellers or immigrants. Three countries of 12 ask about history of G6PD deficiency. Ten countries of 13 map the residences of either the positive cases or of all those that are screened.
Additional Measures
As part of case investigation practices, country programmes implement several types of activities, including vector control, entomological surveillance, or health education. Of the ten respondents who completed this section of the survey, all reported conducting indoor residual spraying (IRS) and a form of health education and behaviour change (information, education communication (IEC) or behaviour change communication (BCC)) as part of the response measures during case investigation or RACD. Six of the eight respondents who answered these questions reported distribution of insecticide-treated bed nets (ITNs) or long-lasting insecticide-treated bed nets (LLINs) as part of these practices. Nine of 11 countries which answered this question use some form of larval control measures as part of a case investigation process. Twelve respondents reported conducting entomological surveillance as part of investigation procedures, three of which do so in all cases. Lastly, targeted mass drug administration (MDA) is conducted as part of case investigation by one country (out of 12 respondents).
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