Prevalence of ehrlichial infection among dogs and ticks in Northeastern Brazil

Abstract

This study investigated the epidemiology of canine ehrlichiosis in Northeastern Brazil, focusing the identification of the Ehrlichia species and vectors involved. Samples were collected from 472 domestic dogs residing in the health districts of Cajazeiras and Itapuã of Salvador city. The average prevalence of antibodies reactive to E. canis by immunofluorescent antibody test (IFAT) (titer ≥ 1:80) was 35.6% (168/472). Blood samples from the E. canis-seropositive animals were tested by nested PCR in order to identify the Ehrlichia species responsible for the infection. Among the seropositives, 58 (34.5%) were found to be PCR-positive for E. canis. Ticks were found in 32 dogs. Nested-PCR analysis showed that 21.9% (7/32) of the Rhipicephalus sanguineus were infected by E. canis. In both dogs and Rhipicephalus sanguineus, nested-PCR for E. ewingii and E. chaffeensis was negative, with no amplification of DNA fragment.Keywords: Ehrlichia, PCR, epidemiology. ResumoEste estudo objetivou pesquisar a epidemiologia da erliquiose canina no Nordeste do Brasil, com especial atenção na identificação da espécie de Ehrlichia envolvida nas infecções caninas e vetoriais detectadas. Para isso foram coletadas amostras de 472 cães domiciliados nos distritos sanitários de Cajazeiras e Itapuã. A prevalência de anticorpos anti-E. canis, pela imunofluorescência indireta (título ≥ 1:80), em cães foi de 35,6% (168/472). Os animais soropositivos foram analisados por uma nested-PCR para identificação da espécie de Ehrlichia responsável pela infecção. Dentre os positivos, 58 (34,5%) cães foram PCR-positivos para E. canis. Foram coletados e classificados os carrapatos em 32 cães. A nested-PCR de Rhipicephalus sanguineus resultou em 21,9% (7/32) de infecção por E. canis. A nested-PCR de amostras de sangue de cães e Rhipicephalus sanguineus para E. chaffeensis e E. ewingii foi negativa, não havendo amplificação de fragmento de DNA.

Survey of Ehrlichia canis, Babesia spp. and Hepatozoon spp. in dogs from a semiarid region of Brazil

“…A similar seroprevalence has been previously observed by Carlos et al (2007) and Souza et al (2010) in Northeastern Brazil. These high titers are consistent with prolonged infection and chronic antigenic stimulation (BARTSCH & GREENE, 1996).…”

Risk factors and clinical disorders of canine ehrlichiosis in the South of Bahia, Brazil

“…The serum prevalence in this study was similar to that found by Souza et al (2010) using IFA, which found a prevalence of 35.6% in Salvador, Bahia. Using the Dot-ELISA test on 2,553 dogs from several Brazilian States, Labarthe et al (2003) found that 505 (19.8%) were positive, with highest prevalence in the States of the Northeast (43%) and lowest in the Southern region (1.7%).…”

“…Since the presence of antibodies reveals exposure to the agent, PCR may help in reaching a diagnostic conclusion. Souza et al (2010) found that 35.6% (168/472) of the dogs examined were seropositive, but that only 58 (34.5%) of these animals were PCR-positive.…”

“…Early diagnosis of ehrlichiosis is important because this is an emerging zoonotic disease (PEREZ et al, 2006). The diagnostic techniques available include blood smears to view inclusions of corpuscles or morulae (BORIN et al, 2009), serum tests, especially Dot-ELISA and the indirect immunofluorescence assay (IFA) (TRAPP et al, 2006), and molecular techniques such as nested PCR (SOUZA et al, 2010).…”

Ehrlichiosis in Brazil

“…In a survey of dogs from rural and urban areas by IFA, the prevalence found in Mato Grosso State (42.5%), Central-West Brazil (SILVA et al, 2010), was higher than in Rondônia State (36%), Northern Brazil (AGUIAR et al, 2007b), Bahia State (35.6%), Northeastern Brazil (SOUZA et al, 2010), and Rio Grande do Sul State (4.8%), Southern Brazil (SAITO et al, 2008). Th e reasons for diff erent prevalences in Southern, Central-West and NorthernNortheastern Brazil are unknown, since R. sanguineus is abundant throughout these urban and rural areas of Brazil (LABRUNA; PEREIRA, 2001;DANTAS-TORRES et al, 2006).…”