Gross Signs Of Disease Research Articles

Prevalence of antibodies to lymphocystis virus in estuarine flounder Platichthys flesus

Serological surveys were conducted on flounder Platichthys flesus L., 1758 populations in 2 German estuaries. The prevalence of antibodies to lymphocystis virus (seroprevalence) was determined by means of an enzyme-linked immunosorbent assay (ELISA). Both seroprevalence and antibody levels in lymphocystis virus antibody positive (seropositive) fish with no gross signs of disease increased with age. These findings suggest that recovery from lymphocystis is common and concomitant with the acquisition of some degree of immunity in the populations studied.

Enzootic paracoccidioidomycosis in armadillos (Dasypus novemcinctus) in the State of Pará

Paracoccidioides brasiliensis foi encontrado, por inoculação de triturado de fígado e baço em hamsters, em 4 de 20 tatus (Dasypus novemcinctus) examinados na região de Tucuruí, Pará. Hamsters inoculados por via intradérmica e peritoneal com o parasito desenvolveram infecções generalizadas e morreram em 1½ a 13 meses. A diagnose do fungo foi confirmada por histopatologia e cultura. Não se observaram sinais macroscópios de doenças nos tatus. A distribuição geográfica de D. novemcinctus abrange a área endêmica de paracoccidioidomicose humana, sugerindo-se que o tatu tenha algum papel na ecologia do fungo.

Pathogenesis and midgut histopathology of Bacillus thuringiensis in Simulium vittatum (Diptera: Simuliidae)

The pathogenesis and midgut histopathology which resulted when larvae of the blackfly, Simulium vittatum, were exposed to Bacillus thuringiensis at various temperatures and periods of exposure were investigated. The onset of mortality was studied at 10°, 15°, 19°, and 24°C. For each 4–5°C increase in temperature above 15°C, the onset of mortality was shortened by 24 hr. Exposures as brief as 15 min to 10 ppm of a whole spore preparation resulted in an average mortality of 29% in late-instar larvae. Mortality increased sharply for exposures up to 3 hr, approaching a maximum of 80%. The gross signs of disease included cessation of feeding and tetany with brachytosis. The tissue most affected was the midgut epithelium in the regions of the gastric caeca and posterior stomach. The formation of cytoplasmic vacuoles followed by cell lysis and/or sloughing were very apparent in moribund larvae. Death resulted without bacteremia.

TRANSMISSION OF LEUCOCYTOZOON BONASAE CLARKE TO RUFFED GROUSE (BONASA UMBELLUS L.) BY THE BLACK FLIES SIMULIUM LATIPES MG. AND SIMULIUM AUREUM FRIES

Specimens of Simulium aureum, S. latipes, S. venustum, and S. rugglesi feed on ruffed grouse although relatively few engorged specimens of the two latter species were obtained. S. aureum and S. latipes are suitable hosts for Leucocytozoon bonasae as shown by infections produced in grouse following injections of sporozoites removed from the salivary glands of these flies. The parasitaemia in grouse infected naturally and experimentally was relatively low and no gross signs of disease were noted in any of the infected birds.