Reactive Case Detection of Asymptomatic Malaria in Households and Neighbors of Laboratory Confirmed Cases in Raya Kobo District, Northeast Ethiopia

Abstract

Background Malaria is the leading vector borne parasitic disease causing enormously high morbidity and mortality worldwide. There have been huge efforts so far to control and eliminate malaria in the world. However, high prevalence of asymptomatic carriage poses a threat on malaria control and elimination programs. Since asymptomatic infections present no overt sign and symptoms, they do not get clinical attention. Moreover, asymptomatic cases are a potential source of infection in high and low transmission settings. Despite the presence of some pocket data, the prevalence of asymptomatic carriage has not yet been known nationally and the current study area as well. Therefore, we aimed to assess the prevalence of asymptomatic malaria cases and associated factors in households and neighbors of laboratory confirmed cases in Raya Kobo district, Northeast Ethiopia. Methods: A community based cross-sectional study was conducted from February to April, 2019 among 270 study participants selected by convenient sampling technique at the community where laboratory confirmed cases were found. A structured questionnaire was used to collect data on socio-demographic characteristics, individual and household level factors. The data were entered in Epi Data 3.1 version and analyzed by using SPSS version 20. Variables with P<0.25 in the bivariable analysis were taken to the multivariable analysis to control potential confounders, and p< 0.05 was considered statistically significant. Results: The overall prevalence of asymptomatic malaria was 7.0%, with 3.0%, 5.2% and 12.0%, respectively by Rapid diagnostic tests (RDT), Microscopy and Polymerase chain reaction (PCR). Majority of the infections (73.7%) were identified from index households. PCR detected asymptomatic infections about 2.7 and 2.3 folds higher than RDT and microscope, respectively. Previous malaria history (AOR: 4.030, 95% CI: 1.021-15.903), living with index cases (AOR: 3.880, 95% CI: 1.275-11.806) and family size > 6 members (AOR: 4.820, 95% CI: 1.260-18.437) were significant predictors of Plasmodium spp infection.Conclusion: Reactive case detection had identified considerably higher asymptomatic malaria cases at the community. Therefore, active case investigation should be established in the community by tracking the symptomatic cases at the health facilities. Diagnostic tests involving the PCR should be implemented in the surveillance of asymptomatic malaria. Active malaria cases should also be treated.

Prevalence of asymptomatic malaria and associated factors in Ethiopia: Systematic review and meta-analysis

“… 25 The age group used for analysis was not consistent across the studies. Of the 14 studies included in the final analysis, 7 were conducted in Amhara Region, 26 – 32 4 in SNNPR, 24 , 33 – 35 2 in Oromia, 25 , 36 and 1 in Benishangul-Gumuz. 37 Fifty percent of the studies were community-based.…”

“… 37 Fifty percent of the studies were community-based. 27 – 29 , 32 , 33 , 35 , 36 The outcome measure was only RDT for two studies, 27 , 37 only microscope for five studies, 24 , 28 , 29 , 31 , 35 and both microscopy and RDT for seven studies. 25 , 26 , 30 , 32 – 34 , 36 The studies done by microscopy have identified the species, while two of the RDT result did not ( Table 1 ).…”

“… 33 – 35 The rest six studies did not follow these transmission patterns. 24 , 29 – 32 , 36 Except for one 26 where malaria is endemic, malaria is seasonal and unstable in the rest areas.…”

“…Seven studies were selected to assess the association between educational level and asymptomatic malaria infection. 26 – 28 , 31 – 33 , 35 A random-effect model was used for this analysis as there is heterogeneity ( I 2 = 80.6%, p -value = 0.009). However, two studies indicated there was a significant association between educational level and asymptomatic malaria infection, 28 , 33 the pooled analysis revealed that there is no significant association between educational level and asymptomatic malaria infection (OR = 0.77; 95% CI = 0.38, 1.54) ( Figure 12 ).…”

“…There were seven studies selected to assess the association between IRS service and asymptomatic malaria. 26,27,29,32,33,36,37 Three studies 27,29,37 showed no statistically significant association while four studies, 26,32,33,36 indicated statistically significant association.…”