Host antibodies in mosquito bloodmeals: a potential tool to detect and monitor infectious diseases in wildlife.

When a female mosquito bites, it carries away a blood sample containing specific antibodies that can provide a history of the immune responses of its vertebrate host. This research examines the limits and reliability of a technique to detect antibodies in blood-fed mosquitoes in the laboratory. Mosquitoes were fed on blood containing a specific antibody, and then they were assayed using an enzyme-linked immunosorbent assay to determine the limits of detection of antibody over time, at different temperatures and initial antibody concentrations. The antibody, at an initial concentration of 1 microg/ml, could be detected in mosquitoes for 24-48 h after feeding. Blind tests simulating the assay of feral mosquitoes were used to test the reliability of the method and detected positive mosquitoes with few false negatives and no false positives. Specific antibodies also could be detected in mosquitoes that had been air-dried or preserved in ethanol. This research indicates that, in theory, the collection and immunological assay of blood-fed mosquitoes could be developed to detect and monitor infectious disease in wildlife.

Intestinal parasites of raccoons (Procyon lotor) from southwest British Columbia.

This is the first extensive survey of metazoan parasites (particularly of the roundworm Baylisascaris procyonis) from the intestines of raccoons in British Columbia. The sample collected in 1997-1998 consisted of 82 raccoons that had been sick or had been killed accidentally by automobiles. Fifteen parasite taxa were found: 3 nematodes, 9 digenetic trematodes, 2 acanthocephalans and 1 cestode. Ten of these parasites constitute new host records for raccoons, including 4 digenetic trematodes that have been reported in marine birds and mammals on the Pacific Coast of North America. Baylisascaris procyonis infected 61% of the raccoons with a mean intensity of 27. The high rate of infection indicates a large potential for environmental contamination and, thus, human and animal exposure to infectious eggs. Prevention of larva migrans is discussed, particularly for people in contact with raccoons in wildlife rehabilitation centers.

Ecological factors in schistosome transmission, and an environmentally benign method for controlling snails in a recreational lake with a record of schistosome dermatitis.

The avian schistosomes, Trichobilharzia stagnicolae, T. physellae and Gigantobilharzia sp., that cause Schistosome Dermatitis (Swimmers' Itch) in humans were studied in the laboratory and at Cultus Lake, British Columbia, Canada in relation to the biology and behavior of their intermediate snail hosts, Stagnicola catascopium, Physa sp. and Gyraulus parvus, respectively, and their definite bird hosts. Wind-driven, surface currents were measured. Populations of snails, close to host-bird roosting logs had a very high prevalence of schistosome infections. An experiment that mechanically disturbed the epilithic habitat of the snails using a boat-mounted rototiller or a tractor and rake, eliminated almost all of the snails if the disturbance was done in areas of high snail concentration in shallow areas of the lake during the breeding and early development phase of the snail. It is proposed that the incorporation of snail habitat disturbance into management programs is an effective way to control Schistosome Dermatitis.