Mechanical transmission of Eperythrozoon suis Splitter by arthropod vectors
Abstract
The ability of blood-feeding Diptera to serve as vectors of Eperythrozoon suis Splitter was evaluated by establishing an association between these flies and E. suis thru a pig-baited trap, feeding trials, and indirect fluorescent antibody technique. The majority of the diptera trapped on a farm where E. suis infections had been diagnosed serologically were Stomoxys calcitrans (L.) and Culex pipiens L. and other species in fewer numbers. Results indicated S. calcitrans, Cx. pipiens, and Aedes sp. could be important mechanical vectors. Stomoxys calcitrans and Ae. aegypti were tested to determine their ability to transmit E. suis between swine. Three groups of each insect in each trial were allowed to feed on a pig previously infected with E. suis and transferred to susceptible splenectomized pigs. As control, 1 group of each insect was fed on an uninfected pig and transferred to a susceptible splenectomized pig. Stable flies were transferred immediately and following a delay of 1,4 and 24 hours and 7 days. Aedes aegypti were transferred immediately and following a 7 day delay. Successful transmission was accomplished when S. calcitrans and Ae. aegypti were transferred from infected to susceptible pigs. No pigs became infected when there was a delay before transfer to the susceptible pig. All controls remained uninfected. This indicates that S. calcitrans and Ae. aegypti are likely to be mechanical vectors of E. suis. Differences in vector efficiency may be due to differences in mechanisms of blood-feeding. Serum from naive and convalescent pigs was collected for use in an indirect fluorescent antibody test. Reactivity with E. suis was established by incubating thin blood smears from E. suis infected and uninfected pigs with these sera. Specific fluorescence was not detected in the sections of unfed Ae. aegypti and S. calcitrans incubated with these sera. Sections of gut and mouthparts from Ae. aegypti and S. calcitrans fed on infected and uninfected pigs were incubated with convalescent and naive serum for comparison and evaluation of the stained tissue fluorescence. Eperythrozoon suis was detected only in undigested blood in the gut. No fluorescence could be detected on the mouthparts of either vector.
Degree
Ph.D.
Advisors
Williams, Purdue University.
Subject Area
Entomology
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