There have been eleven laboratory confirmed cases of epidemic polyarthitis in Katherine since the start of
December 1988. This indicates a relatively serious degree of mosquito disease transmission and has followed this Department's efforts in the latter part of 1988 to prevent such an outbreak. A full investigation of the mosquito breeding situation and the potential for disease transmission was carried out on September 13-14, 1988, and the resultant report presented to the relevant authorities. Following the confirmation of the present disease outbreak in Katherine, carried out a comprehensive adult mosquito collection was over the period 6-8 February to assess the current mosquito situation, and to collect adult mosquitoes for virus investigations. This survey revealed significant mosquito levels in various localities. The current investigation was to confirm the sources of these mosquitoes and to discuss the situation with relevant authorities.