Lymphatic filariasis in Bilaspur district, Chhattisgarh.

As per earlier reports only Ratanpur PHC of the district Bilaspur of Chattisgarh was endemic for filariasis. During the present survey microfilaria infection and disease manifestations were detected in two more PHCs namely Bilha and Bilaspur. 3426 Night blood smears were collected from 24 randomly selected localities (13 rural and 11 urban) covering 25% known endemic areas and 75% reportedly non-endemic areas. Sample size was calculated taking 12% prevalence rate using standard statistical formula. Sixty-two indigenous residents (mf rate 1.80%) were found positive for W. bancrofti infection. Males (2.17%) were more affected than females (1.19%). The mf carriers were 2.05% in rural and 1.45% in urban communities, which indicates that lymphatic filariasis is prevalent in rural areas also. The mean mf density was 5.06. No infective or infected mosquitoes could be detected in Culex quinquefasciatus (544 nos.), M. annulifera (13 nos.) and M. uniformis (2 nos.). Comparing the earlier studies, in Bilaspur district the infection has been showing a declining trend and Brugia malayi infection has disappeared.