Effectiveness of pernanet® 2.0 and Olyset® for malaria prevention in children under five years in Kisumu Disstrict, Kenya
Majwa, Philimon Omondi
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Globally, there are an estimated 247 million malaria cases and 3.3 billion people at risk. In Kenya an estimated 11.3 million malaria cases have been reported with 27,000 deaths due to malaria. Long-lasting insecticidal nets (LLINs) are advocated by World Health Organisation (WHO) for protection against malaria. In Kenya the National Malaria Control Programme (NMCP) distributed 7.1 million insecticide treated nets (ITNs) in 2006, of which 6.3 million were LLINs. Within Kisumu district, the proportion of children under 5 years who benefited from this campaign increased from 24% in 2006 to 65% in 2007. Paradoxically however, the malaria incidence within children under 5 years increased from 162,000 in 2006 to 184,000 in 2007. The objective of the study was therefore to determine whether socio-cultural factors reduces the effectiveness of the PermaNet® 2.0 and Olyset® as interventions in controlling malaria within children under 5 years in Kadibo division, Kisumu district. A questionnaire was administered to 306 respondents in Kadibo Division. From the respondents who were interviewed 47% had one net, 29% had two, 14% had three and 5% had four (x2=2.433, p<_0.876). Most of the nets (54%) were obtained from the Health facilities, while 46% were bought from shops, chemist and market places. Furthermore, 68% of the freely distributed nets from health facilities were of PermaNet© 2.0 brand while 32% were of Olyset® brand. A good proportion of the respondent (93%) confirmed that they had used nets the previous night (x2=1.686, p<0.430). Only 12% of the households had nets with no holes. Most households (63%) reported having nets with between 1-5 holes while 25% reporting had nets with 6-45 holes. During the period of the use of the net, 70% of children sleeping under it reported contracting malaria in the previous six months compared to 30% who had not contracted malaria. Out of the children who had contracted malaria, 12% had suffered from malaria once, 36% had suffered from malaria twice and 31 % had suffered from malaria more than thrice while 21% had not contracted malaria. The proportion of sleeping rooms exposed to heat and smoke from cooking area was 70%. Thus, the heat generated by the hearth and the adsorbed smoke particles on the net is suspected to affect the effectiveness of the LLINs. Most of the respondents preferred green and blue oval shaped nets while the white ones were reserved for guests, funerals and wedding gowns. Majority of respondents adhered to the requirement that the nets should be washed at most 10 times within 2 years of use. In this study, 75% of the respondents washed the nets 5 times within the two years of use. Samples of Olyset® and PermaNet® 2.0 nets, which had been in use in Kadibo villages for 2 years (x2=2.708, p<_0.439), were tested in laboratory bioassay for their vector knockdown capacities (KD) against Anopheles gambiae mosquitoes. An ideal LLIN should have an 80% mosquito knockdown for KD3, KD60 and KD24, however the results of this study showed that PermaNet® 2.0 had KD3 7%, KD60 7.9% and KD24 12.9%. Olyset@ net had KD3 4.1%, KD60 6.7% and KD24 8.7% thus it is evident that PermaNet® 2.0 though with a dismal performance is more effective than Olyset® (x2=10.083, p<0.040). The results suggest on one hand, that the PermaNet® 2.0 and Olyset® do not contain sufficient insecticide to knockdown mosquitoes and on the other hand, that the mosquitoes may have developed resistance to the insecticide. These results show that the PermaNet® 2.0 and Olyset® in Kadibo division are not effective against the prevention of malaria to children under 5 years after 2 years of use. This study recommends that the National Malaria Control Programme should check the compliance of the PermaNet® 2.0 and Olyset® at source for quality.