สถาบันวิจัยวิทยาศาสตร์สาธารณสุข

National Institute of Health of Thailand

Authors : Uruyakorn Chansang Mir S. Mulla and Pathom Sawanpanyalert
Affiliations : 

 National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand

Source : J  Vector Ecol  2007; 32: 292-301.
Language : English

Abstract :

 
 

          Species of eye flies and eye gnats (Diptera: Chloropidae) are severe and persistent pests of man, domestic and wild animals, and potential vectors of pathogens. The species prevailing in the oriental region belong to the genus Siphunculina while those in the neotropic and nearctic regions belong to Liohippelates and Hippelates. These are small 1-2 mm insects which feed on wounds, lacerations, scratches and mucous membranes of man and higher animals. One species Siphunculina funicola, commonly known as the oriental eye fly is considered as the most anthropophilic in the genus, with potential involvement in the spread and mechanical transmission of infectious agents to humans and animals. Very little is known about the biology, prevalence, host-seeking and aggregation behavior of this species in South and Southeast Asia. We initiated studies on biological aspects of this potential vector and human pest in central Thailand. The most significant findings of our study were the aggregation behavior of S. funicola, and that both sexes attack hosts and that males outnumbered females attacking humans, dogs and possibly other domestic animals most of the time. They were seen to feed on wounds, scabs, lacerations, eyes and mucous membranes. We noted them to hover around and feed on hosts during the daylight hours when host-seeking activities were more pronounced at temperatures above 25-27 oC under calm conditions. We noted that large masses of males and females aggregated on a variety of hanging substrates such as strings, trailings, electrical lines, decorations, ropes, twines, abandoned cob webs, clothes hangers and other hanging substrates in open shade of structures and dwellings. This behavior of eye flies brings them closer to human and animal hosts. In these aggregations, both males and females were present, with mating pairs frequently noted. In the aggregations, about 37% of the females had fully developed eggs in the rainy season, but only <1-3.6%  were gravid in the hot and dry season. The average number of eggs per female was generally 42 to 44.