Investigation of outbreak of malaria in tribal area of Visakhapatnam, Andhra Pradesh

The findings of an epidemiological investigation undertaken in Paderu divis ion of Visakhapatnam district, Andhra Pradesh are reported in the present c ommunication. The slide positivity rate (SPR) was still high (maximum SPR w as 70) in spite of intensive surveillance and fever radical treatment in th e affected areas. The vector, Anopheles culicifacies, was found resistant t o DDT, but susceptible to Malathion and Deltamethrin. However, the finding of An. culicifacies in only 4 villages out of 12 tribal villages surveyed, and that too with highest density of 13.3, indicated that DDT was still hav ing some impact, In a small sample, Plasmodium falciparum parasite was foun d resistant to chloroquine. The possible reasons of outbreak may be: (i) la ck of surveillance and expertise in detection of malaria parasite; (ii) ine ffective radical treatment as indicated by resistance in P, falciparum, and (iii) improper coverage of indoor residual DDT spraying in 1998. Advanced rains in the month of May 1999 also added to the hindrance in surveillance and control measures in the hilly terrain of the affected area. Suggestions for management of such outbreaks in future are discussed.