Attempted Ehrlichia risticii transmission with Dermacentor variabilis (Acari: Ixodidae).

Larval Dermacentor variabilis (Say) (n = 327) were fed on Balb/C mice inoculated with Ehrlichia risticii, the etiologic agent of equine monocytic ehrlichiosis (Potomac horse fever). All mice displayed clinical signs of E. risticii infection at the time of feeding. After molting, resulting nymphs (n = 74) were fed on susceptible mice. No clinical signs were observed, and the mice remained seronegative for 6 wk after feeding.

Attempted mechanical transfer of Ehrlichia risticii by tabanids (Diptera: Tabanidae).

The ability of tabanid mouthparts to retain and to transfer mechanically Ehrlichia risticii Holland, Weiss, Burgdorfer, Cole & Kakoma was evaluated by feeding flies on infected and noninfected mice and on capillary tubes containing infected cells and cell-free medium. Flies representing two genera and 29 species were collected at equine boarding stables, farms, and along riding trails in Wake, Johnston, and Duplin counties in North Carolina for the feeding trials. Two species, Tabanus fulvulus Wiedemann and T. pallidescens Philip, fed on mice but failed to transfer the pathogen from infected to susceptible mice. Chrysops vittatus Wiedemann, Tabanus americanus Forster, and T. sulcifrons Macquart transferred E. risticii-infected cells from capillary tubes containing infected cells in medium to tubes containing medium. These studies document that E. risticii-infected cells can be retained on mouthparts and potentially transferred by tabanids.

Immunoblot analysis of the immunoglobulin G response to Ehrlichia canis in dogs: an international survey.

Historically, considerable variation has been reported in the type and severity of clinical and hematologic abnormalities associated with canine ehrlichiosis. Because of difficulties associated with the isolation of intracellular monocytic Ehrlichia species in tissue culture systems, few E. canis isolates are available for comparative microbiologic studies. To address the issue of potential E. canis antigenic diversity in different regions of the world, dog sera reactive by indirect fluorescent antibody testing to E. canis (Florida) antigen were obtained from France, Israel, Italy, the United States, the Virgin Islands, and Zimbabwe. Ehrlichia canis proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, and at least 5 sera from each region were stained by western immunoblotting. Antibody immunodominance was scored based upon staining intensity. There was relative homogeneity in the immunogenic protein reactions to E. canis antigens. Of the 58 E. canis reactive sera, 54 samples resulted in immunoblot patterns indicative of chronic ehrlichiosis. Four reactive sera (reciprocal titers of 160-2,560) did not recognize any genus-specific antigens resulting in protein bands between 22 and 29 kD, indicating serologic cross-reactivity with other microorganisms. Relatively homogenous immunoblot patterns, consistent with the reported immunoblot response of dogs with experimental chronic ehrlichiosis, were observed with sera from Arizona, France, Israel, North Carolina, Texas, and the Virgin Islands. In contrast, unique major proteins were observed in dog sera from Italy and Zimbabwe. Our results indicate that although relatively homogeneous, antigenic diversity may exist among E. canis organisms in different regions of the world.

Diarrhea associated with trichomonosis in cats.

OBJECTIVE: To establish clinical features, course of illness, and treatment outcome of cats with diarrhea and concurrent infection with Trichomonas organisms. Prevalence of fecal trichomonads in a geographically comparable population of healthy indoor and feral cats also was assessed. DESIGN: Longitudinal study and a cohort study. ANIMALS: 32 cats with diarrhea and naturally acquired trichomonosis that were native to North Carolina, Virginia, Connecticut, and Tennessee; 20 healthy indoor cats; and 100 feral cats. PROCEDURE: Trichomonosis was diagnosed in 32 cats by identification of organisms in fresh feces or by protozoal culture of feces. RESULTS: Diarrhea associated with the large intestine and trichomonosis were diagnosed in 32 cats. Median age of the cats was 9 months; 23 cats were < or = 1 year old at the time of diagnosis. Two cats developed diarrhea accompanied by infection with Trichomonas organisms after the addition of an infected kitten into the home. Duration of diarrhea ranged from 2 days to 3 years. Six cats had a coexisting enteric infection. Treatment with antimicrobials improved fecal consistency and reduced the number of flagellates in the feces, but did not eliminate infection. Diarrhea (with microscopically detectable flagellates) was observed shortly after antibiotics were discontinued. Trichomonads were not recovered from feces of any healthy indoor or feral cats. CONCLUSIONS AND CLINICAL RELEVANCE: Our findings suggest that trichomonosis may be a cofactor in development of diarrhea in young cats. Trichomonas organisms were not identified as part of the indiginous fauna of healthy indoor or feral cats.

Babesia gibsoni infections in dogs from North Carolina.

The recognition of canine babesiosis in North Carolina caused by Babesia gibsoni documents the expansion of the previously reported endemic area of this disease. Clinical signs ranged from severe hemolytic anemia and thrombocytopenia to subclinical infections. No infected dogs had traveled to endemic areas. Antibabesial treatment failed to eradicate the organism from infected dogs.