Studies on the medical ecological epidemiology in Mangrove areas in Thailand

Abstract

Studies on the medical ecological epidemiology in the mangrove areas in Chantaburi and Cholburi provinces of East Thailand were made during Nov. to Dec. 1972. The brief surveys were carried out in 5 villages of Kloong district in Chantaburi and at 2 places in Muang district of Cholburi in order to obtain some basic information on some diseases and vectors, and rats and their ectoparasites. The results revealed the following: Mosquitoes: Culex sitiens was the most prevalent species followed by Aedes dux. The breeding places of the former were in salty marshes while those of the latter were in tree holes. Both species especially Ae. dux were greatly reduced in number when the mangrove trees were cut down. Ae. aegypti was not uncommonly found. There were practically no mosquitoes during the day time hours. Rodents: Six species of rodents were found; Rattus rattus was the most prevalent followed by R. losea. Both were caught mostly from the short mangrove areas. Ectoparasites: Seven species of chigger mites and one louse species were recovered, but their numbers were not many. Leptothrombidium deliensis, the potential vector of scrub typhus in Thailand, was also found from some of the mangrove areas. Malaria parasites were not found in these areas. Dengue haemorrhagic fever has been reported in these areas since June 1971. Many clinical cases were still in the local hospital and 21% of the children in villages gave positive results for arbovirus antibodies.