Domestic dogs as amplifying hosts of Rickettsia rickettsii for Amblyomma aureolatum ticks

Autor(es)

Binder, Lina C. ; Ramirez-Hernandez, Alejandro ; de Azevedo Serpa, Maria Carolina ; Moraes-Filho, Jonas ; Pinter, Adriano ; Scinachi, Claudia A. ; Labruna, Marcelo B.

• Tipo de documento: Artigo Científico
• Fonte: TICKS AND TICK-BORNE DISEASES; v. 12, n. 6, p. 8-pg., 2021-11-01.

Resumo

Brazilian spotted fever (BSF) is an acute infectious disease caused by the bacterium Rickettsia rickettsii, which is transmitted by different tick species. Due to deleterious effects caused on ticks, the horizontal transmission of R. rickettsii through amplifying hosts is crucial for its maintenance in tick populations among B SF-endemic areas. The tick Amblyomma aureolatum is the main vector of R. rickettsii in the Sao Paulo metropolitan area; nevertheless, it is not known which vertebrate could act as an amplifying host for this tick species. Herein, we evaluated the potential of domestic dogs - primary hosts for A. aureolatum adults in BSF-endemic areas - to act as amplifying hosts. For this purpose, A. aureolatum non-infected adults were allowed to feed on two groups of dogs: the control group (G1), composed of one dog not exposed to R. rickettsii; and, the infected group (G2), composed of three dogs infected with R. rickettsii via tick parasitism. All G2-dogs became ill, semconverted to R. rickettsii, and rickettsial DNA was detected in 87% of the engorged females that fed on them. Transovarial transmission rate was estimated to be 25% and infected larvae successfully transmitted R. rickettsii to guinea-pigs, confirming transovarial transmission and vector competence. No rickettsial DNA was detected in individual samples of eggs or larvae, which precluded the estimation of filial infection rate, but implies that it was low. Our results suggest that domestic dogs act as amplifying hosts of R. rickettsii for A. aureolatum ticks in BSF-endemic areas in Brazil. (AU)

• Processo FAPESP: 18/01596-8 - Avaliação de possíveis variáveis epidemiológicas associadas à distribuição espacial da infecção por Rickettsia rickettsii em cães e carrapatos em uma área endêmica para Febre Maculosa Brasileira na Região Metropolitana de São Paulo
• Beneficiário: Lina de Campos Binder
• Modalidade de apoio: Bolsas no Brasil - Mestrado