Spotted fever in indigenous communities from Atlantic Forest areas of Southeastern Brazil
1
Department of Preventive Veterinary Medicine and Animal Health, University of São Paulo, São Paulo, Brazil
2
Zoonosis Surveillance Unit, City Secretary of Health, Curitiba, Brazil
3
Department of Epidemiology and Public Health, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
4
Institute of Science and Technology in Biomodels, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
5
Department of Veterinary Medicine, Federal University of Paraná, Curitiba, Brazil
Popul. Med. 2026;8(Supplement Supplement 1):A1937
ABSTRACT
BACKGROUND:
Spotted fever is a severe tick-borne zoonosis endemic to southeastern Brazil, including Atlantic Forest areas1. Indigenous communities in these settings may face increased risk due to contact with forested environments, wildlife, hunting dogs, and tick vectors2.
METHODS:
A cross-sectional study was conducted in Indigenous communities located in coastal areas of Rio de Janeiro and São Paulo. Serum samples were collected from 550 humans and 210 dogs across 11 villages and tested for anti-Rickettsia antibodies by indirect immunofluorescence assay3. Ticks were collected from infested dogs and analyzed by molecular methods, totaling 70 specimens to date4.
RESULTS:
In São Paulo, dogs were seropositive for Rickettsa parkeri (51.5%, 34/66), Rickettsia amblyommatis (28.8%), and Rickettsia rickettsii (24.2%), with fourfold higher titers to R. parkeri in 22.7%; humans showed seroreactivity to R. parkeri (23.7%, 50/135), R. amblyommatis (11.1%), and R. rickettsii (10.4%), with fourfold higher titers to R. parkeri in 9.6%. In Rio de Janeiro, dogs showed seroreactivity to R. parkeri (32.2%, 50/142), R. amblyommatis (31.7%), and R. rickettsii (27.5%), with fourfold higher titers to R. parkeri in 7%, while humans showed R. parkeri (9.2%, 38/415), R. amblyommatis (7.7%), and R. rickettsii (6.7%), with fourfold higher titers to R. parkeri in 3.1%. Among 70 adult ticks collected from dogs, 24.3% (17/70) were PCR-positive for the gene ompA, common to spotted fever group rickettsiae. All positive ticks were identified as Amblyomma ovale, and ompA-sequences confirmed R. parkeri. By the time of the WCPH Congress, an additional 1000 human samples, 300 dogs, and 1000 ticks are expected to be evaluated, enabling the presentation of updated results.
CONCLUSIONS:
Healthcare professionals of areas reported febrile patients with inoculation eschars compatible with R. parkeri spotted fever. The results indicate active circulation of R. parkeri and reinforce the need for context-specific surveillance tailored to their way of life.
Spotted fever is a severe tick-borne zoonosis endemic to southeastern Brazil, including Atlantic Forest areas1. Indigenous communities in these settings may face increased risk due to contact with forested environments, wildlife, hunting dogs, and tick vectors2.
METHODS:
A cross-sectional study was conducted in Indigenous communities located in coastal areas of Rio de Janeiro and São Paulo. Serum samples were collected from 550 humans and 210 dogs across 11 villages and tested for anti-Rickettsia antibodies by indirect immunofluorescence assay3. Ticks were collected from infested dogs and analyzed by molecular methods, totaling 70 specimens to date4.
RESULTS:
In São Paulo, dogs were seropositive for Rickettsa parkeri (51.5%, 34/66), Rickettsia amblyommatis (28.8%), and Rickettsia rickettsii (24.2%), with fourfold higher titers to R. parkeri in 22.7%; humans showed seroreactivity to R. parkeri (23.7%, 50/135), R. amblyommatis (11.1%), and R. rickettsii (10.4%), with fourfold higher titers to R. parkeri in 9.6%. In Rio de Janeiro, dogs showed seroreactivity to R. parkeri (32.2%, 50/142), R. amblyommatis (31.7%), and R. rickettsii (27.5%), with fourfold higher titers to R. parkeri in 7%, while humans showed R. parkeri (9.2%, 38/415), R. amblyommatis (7.7%), and R. rickettsii (6.7%), with fourfold higher titers to R. parkeri in 3.1%. Among 70 adult ticks collected from dogs, 24.3% (17/70) were PCR-positive for the gene ompA, common to spotted fever group rickettsiae. All positive ticks were identified as Amblyomma ovale, and ompA-sequences confirmed R. parkeri. By the time of the WCPH Congress, an additional 1000 human samples, 300 dogs, and 1000 ticks are expected to be evaluated, enabling the presentation of updated results.
CONCLUSIONS:
Healthcare professionals of areas reported febrile patients with inoculation eschars compatible with R. parkeri spotted fever. The results indicate active circulation of R. parkeri and reinforce the need for context-specific surveillance tailored to their way of life.
| eISSN: | 2654-1459 |
We process personal data collected when visiting the website. The function of obtaining information about users and their behavior is carried out by voluntarily entered information in forms and saving cookies in end devices. Data, including cookies, are used to provide services, improve the user experience and to analyze the traffic in accordance with the Privacy policy. Data are also collected and processed by Google Analytics tool (more).
You can change cookies settings in your browser. Restricted use of cookies in the browser configuration may affect some functionalities of the website.
You can change cookies settings in your browser. Restricted use of cookies in the browser configuration may affect some functionalities of the website.
