LITTLE-ANDAMAN ISLAND, A NEW FOCUS OF INFECTION WITH NOCTURNALLY PERIODIC WUCHERERIA-BANCROFTI

A filariasis survey was carried out for the first time in the Little A ndaman island, covering a population of 12,247 in 12 of the 13 village s, Infection due to Wuchereria bancrofti was found only in 3 villages with microfilaria (mf) rate ranging from 1.02 to 6.45 per cent, Observ ations on the appearance of mf in peripheral blood showed that the par asite is nocturnally periodic form with a peak at 2000 h, The infectio n was prevalent only among the settlers from Bihar and Bangladesh and none of the local tribal population was affected, Carriers included 18 males and 4 females, Their age ranged from 6 to 50 yr, Only one of 27 88 individuals examined was found to have clinical manifestation. A to tal of 442 female mosquitoes belonging to eight species were collected and dissected, Natural infection was found only in Culex quinquefasci atus (0.24%). Epidemiological investigations and vector studies indica tes local transmission. Thus, this island appears as a new focus of in fection.