First Evidence of Rickettsia conorii Infection in Dogs in Northern Tunisia.

Simple Summary: We conducted this study to investigate the role played by dogs in the spread of Rickettsia in Tunisia. Of the 136 dogs that were tested, 55.14% had anti-Rickettsia conorii antibodies while none had Rickettsia DNA. On the other hand, of 51 pools of Rhipicephalus sanguineus ticks collected from these dogs, 7 were Rickettsia DNA positive. These ticks contribute to the circulation of Rickettsia. A cross-sectional study was carried out, between April 2021 and June 2022, to understand the role of dogs in the circulation of rickettsiosis in Tunisia. The presence of specific IgG antibodies against Rickettsia conorii was analyzed by indirect immunofluorescence test. By qPCR, blood and ticks were collected from 136 dogs examined at the Canine Department of National School for Veterinary Medicine of Tunisia. These dogs were also analyzed to detect Rickettsia DNA. The rate of Rickettsia seropositivity in 136 dogs was 55.14%. A total of 51 (53%) seropositive dogs showed clinical and biological signs such as fever and anorexia as well as thrombocytopenia and anemia. By qPCR, targeting the mitochondrial 16S rRNA gene, no Rickettsia DNA was detected in the blood. On the other hand, qPCR followed by sequencing revealed the presence of R. conorii subsp. raoultii in 7 tick pools of the 51 pools composed of the 227 ticks collected. A One Health approach to raise the awareness of dog owners to control tick infestations is imperative, given the dangers of canine zoonoses. [ABSTRACT FROM AUTHOR]