Serosurvey of spotted fever group Rickettsia in equids from western Para, Amazon, Brazil

Abstract

From a previous large epidemiological survey, we randomly selected 474 serum samples (463 horses and 11 mules) distributed among four municipalities of Para state, Amazon region, Brazil, and from three types: farm animal, urban carthorse, and sport horse. Samples were tested by indirect fluorescence antibody test (IFAT >= 64) for antibodies reactive to spotted fever group (SFG) rickettsiae using Rickettsia rickettsii as crude antigens. From the 474 equids tested, 149 (31.4%) had ticks attached during sampling, belonging mostly to the species Dermacentor nitens. The overall seroprevalence for SFG rickettsiae was 31.4% (95% confidence interval: 27.3-35.9%) with 149 seropositive animals out of 474 screened. Notably, 77 equids (16.2%) had high endpoint titers ranging from 512 to 16,384, indicating that they had been exposed to SFG rickettsiae not long before sampling. Animal type affected rickettsial seroprevalence, with significantly higher values among farm horses when compared with urban and sport animals. Presence of dogs and tick infestation were negatively associated with equid seropositivity to R. rickettsii. This is the first report of SFG rickettsiae-reactive antibodies in equids from Para state, Brazilian Amazon.

Keywords

Rickettsia; Ticks; Amazon; Equids

Published in

Experimental and Applied Acarology
2022, Volume: 88, number: 3, pages: 361-370
Publisher: SPRINGER

SLU Authors

• Andersson, Emelie

  • Department of Clinical Sciences, Swedish University of Agricultural Sciences
    

• Norlander, Emma

  • Department of Clinical Sciences, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Pathobiology


Publication identifier

DOI: https://doi.org/10.1007/s10493-022-00753-4

Permanent link to this page (URI)

https://res.slu.se/id/publ/119923