A SMALL SCALE VARIATION IN HUMAN EXPOSURE TO MALARIA  NFECTION IN KOLLA SHARA VILLAGE, SOUTHWESTERN ETHIOPIA:  IMPLICATION FOR TARGETED MALARIA CONTROL
Creators: name: ENDASHAW ESAYAS BODA
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2017

description: Due to the decline of malaria  in many countries,  there is an interest  to eliminate  it. Hence, it is 
important to understand the transmission pattern of malaria to deal with the malaria foci which 
could be the source of infection for other community members. This study aimed to  investigate 
the transmission patterns of malaria and  to identify the sub-villages with higher risk of malaria 
infection towards the  targeted malaria control interventions  in Kolla  Shara  kebele  (“village”), 
southwestern Ethiopia. Both parasitological and entomological studies were carried out from July 
to December, 2016 in the five sub-villages of the Kolla Shara. A total of 591 (in 90 households) 
study participants were followed biweekly by house to house visit for febrile cases. Blood films 
were collected from febrile cases for parasite detection using rapid diagnostic test (RDT) and later 
confirmed by microscope. Anopheles mosquito collection was done  biweekly  in  25 randomly 
selected houses (five houses in each sub-village). Plasmodium circum-sporozoite proteins (CSPs) 
rate of Anopheles arabiensis and An. pharoensis were tested by using Enzyme Linked Immuno-Sorbent Assay (ELISA) technique. A total of 131 febrile cases were screened for malaria using the 
RDT  during the  study  period. Of these, 46 (35.1%) were microscopically confirmed malaria 
episodes. Plasmodium falciparum accounted for 58.7% (27/46) and 41.3% (19/46) was P. vivax 
malaria. The episode of P. falciparum malaria varied among the five study sub-villages. Of the 27 
P. falciparum malaria episodes, 16 (59.3%) were in Abullo, 10 (37.0%) in Erze and only 1 (3.7%) 
episode was from Enmba  sub-village. Moreover, only 30% (27/90) households (in Abullo and 
Erze  sub-villages)  experienced 80.4%  (37/46)  of  the total malaria episodes. Although malaria 
episodes occurred in all age groups, the incidence was higher in children age 5-14 years with IRR: 
4.1 (95% Confidence Interval (CI): 0.7-9.1); P = 0.003. Seven species of Anopheles mosquitoes 
were documented, of which An. arabiensis was  the dominant species (70.5%), followed by An. 
pharoensis (10%). The highest number of Anopheles was collected from Abullo (47%; 511/1086) 
and Erze (32%; 348/1086) sub-villages. Of 733 Anopheles mosquitoes tested for CSPs, eight An.arabiensis were positive for P. falciparum CSP with the overall sporozoite rate of 1.1% (8/733). 
Abullo sub-village had CSP rate of 1.7% (5/299) and EIR of 17.0 ib/p/6 months, and in Erze sub-
village, the SR was 1.4% (3/220) and its EIR was 10.6 ib/p/6 months. The overall estimated EIR 
of An. arabiensis was 5.7 infectious bites/person/6 months. In conclusion, malaria transmission is 
heterogeneous and varied between the five  sub-villages  in a small Kolla Shara village. Higher  malaria incidence, CSP rate and EIR were observed in Abullo and Erze sub-villages. Hence, the 
malaria control programme could target those populations living in high malaria risky sub-villages. 
Moreover, intensifying the existing control interventions in these two malaria foci may make the 
greatest use of resources for effective malaria control.