Detection of Ehrlichia canis in domestic cats in the central-western region of Brazil

Abstract

Ehrlichiosis is a worldwide distributed disease caused by different bacteria of the Ehrlichia genus that are transmitted by arthropod vectors. Its occurrence in dogs is considered endemic in several regions of Brazil. Regarding cats, however, few studies have been done and, consequently, there is not enough data available. In order to detect Ehrlichia spp. in cats from the central-western region of Brazil, blood and serum samples were collected from a regional population of 212 individuals originated from the cities of Cuiabá and Várzea Grande. These animals were tested by the Immunofluorescence Assay (IFA) and the Polymerase Chain Reaction (PCR) designed to amplify a 409 bp fragment of the dsb gene. The results obtained show that 88 (41.5%) cats were seropositive by IFA and 20 (9.4%) cats were positive by PCR. The partial DNA sequence obtained from PCR products yielded twenty samples that were found to match perfectly the Ehrlichia canis sequences deposited on GenBank. The natural transmission of Ehrlichia in cats has not been fully established. Furthermore, tick infestation was not observed in the evaluated cats and was not observed any association between age, gender and positivity of cats in both tests. The present study reports the first serological and molecular detection of E. canis in domestic cats located in the endemic area previously mentioned.

SEROLOGICAL EVIDENCE OF EXPOSURE TO Ehrlichia canis IN CATS

“…IFA results obtained in the present study are in accordance with Braga et al (23) , who found seropositivity of 41.5% to E. canis (cut-off 1:40) among 93 pet cats from Cuiabá, Mato Grosso State (tropical wet and dry climate and Cerrado biome region). This similarity suggests the dissemination of the agent within the host population may be associated with abiotic factors (climate), whereas the higher temperature favors the dispersion of ticks and, hence, the vector-borne diseases (2,25) .…”

“…The occurrence of anti-E.canis IgG antibodies was assessed by IFA, using E. canis strain Cuiabá 16 (21) as antigen with the cut-off point at an initial dilution of 1:40 (9,22,23) . Commercial fluorescein isothiocyanate-conjugated anti-cat IgG (Sigma-Aldrich, USA) was used as conjugate at a dilution of 1:1000, and the antigen preparation and IFA technique were performed as previously described (24) .…”

Tick-borne agents in domesticated and stray cats from the city of Campo Grande, state of Mato Grosso do Sul, midwestern Brazil

“…Ehrlichia sp. closely related to E. canis has been detected in domestic cats sampled in the cities of Viç osa (state of Minas Gerais, southeastern Brazil) (Oliveira et al, 2009), São Luís (state of Maranhão, northeastern Brazil) (Braga et al, 2012) and Cuiabá (state of Mato Grosso, central-midwestern Brazil) (Braga et al, 2014). Recently, Anaplasma sp.…”

Seroprevalence of Ehrlichia canis in dogs from Monterrey, Mexico

“…Melo et al (2011) reported a prevalence of 74.4% in urban and of 67.5% in rural dogs (overall frequency of 70.9%), whereas Witter et al (2013) informed a seroprevalence of 70.1%; in this last study the frequency of E. canis infection was of 23.3% by PCR. On the other hand, also in Brazil a prevalence of E. canis of 41.5% by IFA and of 9.4% was found in cats (Braga et al, 2014).…”