Studies on leptospirosis outbreaks in Peddamandem Mandal of Chittoor district, Andhra Pradesh.

An outbreak of leptospirosis in Peddamandem Mandal, Chittoor district, Andhra Pradesh occurred during Aug to Oct 2005. Out of 86 single human sera samples of suspected cases collected during the investigation, 49 (56.97%) samples from seven villages were found positive for leptospirosis both by DGM tests and IgM antibodies. Out of total 49 positive cases 16 (47.05%) were male and 33 (69.46%) female patients. The mean age of the positive cases were 42.7 years. There was no significant differences in male and female ratio and age groups in affected population. The higher degree of seropositivity was observed in adult females as they were mainly engaged in both domestic and peridomestic works. Geographical clustering of cases was evident. All the 49 positive cases had fever (100%). Myalgia (42.9%), stiffness of calf muscles (55.1%) and headache (32.6%) were the other major clinical features observed. There was only 1 (2.04%) case with conjunctival suffusion. None of the case presented with jaundice. All the suspected cases were tested negative for malaria, typhoid and dengue fever. In Peddamandem, contaminated water stagnation due to heavy rainfall and frequent contact of barefooted villagers with the infected sources registered higher incidence of leptospirosis. Most of the cases were from the contaminated water logged areas of the affected villages. In the affected villages none of the individual occupational category showed a significant association with seropositivity. It indicated that the transmission was from the common single category source in the villages i.e. contaminated stagnant water. The villagers living with livestocks and rodents were significantly associated with seropositivity.