A SMALL SCALE VARIATION IN HUMAN EXPOSURE TO MALARIA  INFECTION IN KOLLA SHARA VILLAGE, SOUTHWESTERN ETHIOPIA:  AN 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.