Ectoparasite Infestations and Canine Infection by Rickettsiae and Ehrlichiae in a Semi-Arid Region of Northeastern Brazil

Abstract

This study investigated the prevalence of Rickettsia spp. and Ehrlichia canis infection in dogs and their ectoparasites from rural and urban areas of two municipalities, Petrolina and Juazeiro, within a semiarid region (Caatinga biome) of northeastern Brazil, by immunofluorescence assay (IFA) and polymerase chain reaction (PCR). Overall, 12.1% (61/504) and 23.0% (116/504) of canine plasma samples had antibodies reactive to Rickettsia spp. and E. canis. E. canis DNA was detected by PCR in 8.3% (42/504) of canine blood samples, whereas no blood sample was positive for Rickettsia spp. The infection by E. canis was determined by PCR in 4.9% (14/285) Rhipicephalus sanguineus sensu lato (s.l.) ticks and by Rickettsia felis in 1.1% (3/285) and 40.6% (74/182) ticks and fleas, respectively. Multivariate regression analyses revealed that canine seropositivity to Rickettsia spp. was associated statistically with the variables ''to reside in Petrolina'' and ''presence of ectoparasites.'' Our results indicate that canine infection by E. canis might be endemic in the Caatinga biome as it is in other Brazilian biomes. Although no previous serosurvey for Rickettsia spp. has been conducted on dogs from the Caatinga biome, our values are much lower than the ones reported for rural dogs from other Brazilian biomes. These differences are likely related to the semiarid climate of the aatinga biome, which minimizes the exposure of rural dogs to Amblyomma spp. ticks, the most common vectors of Rickettsia spp. in Brazil. Considering that dogs are excellent sentinels for human exposure to Rickettsia spp., we can infer that the risks of human acquiring tick-borne rickettsiosis in the Caatinga region of the present study are low. The rickettsial infection rates in fleas and ticks were not related to canine seropositivity; i.e., areas with higher Rickettsia infection rates in fleas had the lowest canine seroreactivity to Rickettsia spp.

Ehrlichia canis and Rickettsia spp. in dogs from urban areas in Paraiba state, northeastern Brazil

“…According to Piranda et al (2008) the presence of seropositive animals indicates the circulation of Rickettsia of the SFG in an area at least 6-18 months earlier. As common hosts of tick-vectors for BSF, dogs are an important marker for disease in surveillance studies, and the occurrence of serologically positive dogs in a geographical area indicates the threat of human infection (ARAES-SANTOS et al, 2015).…”

Occurrence of Ehrlichia canis and Hepatozoon canis and probable exposure to Rickettsia amblyommatis in dogs and cats in Natal, RN

“…A similar seropositivity rate was previously observed by Costa et al (2015), who found antibodies to this agent in 14.6% of the dogs from rural and urban areas of the state of Maranhão, Brazil. Higher seropositivity rates among dogs have been reported in studies conducted in other states in northeastern Brazil: Paraíba 72.5%, 69.4%, 23% and 34% (ARAES-SANTOS et al, 2015;AZEVEDO et al, 2011;ROTONDANO et al, 2015;TANIKAWA et al, 2013); and Bahia 23.0%, 36% and 35.6% (ARAES-SANTOS et al, 2015;CARLOS et al, 2007;SOUZA et al, 2010).…”

<b>Epidemiological aspects of tick-borne diseases in wild and domestic animals of two environmental protection areas in the city of Natal, Rio Grande do Norte State, Brazil</b>

“…Other highest values of seropositivity in dogs were reported in Northeastern Brazil: Paraiba 72. 5%, 69.4%, 23% and 34% (AZEVEDO et al, 2011;TANIKAWA et al, 2013;ARAES-SANTOS et al, 2015;ROTONDANO et al, 2015), and Bahia 23.0%, 36% and 35.6% (CARLOS et al, 2007;ARAES-SANTOS et al, 2015). and inclusions, suggestive of Ehrlichia spp., were detected in 6.5% (13/198) of dogs with clinical signs suggestive of canine monocytic ehrlichiosis (MEDEIROS; LIMA, 2004).…”