Survey of canine tick-borne diseases in Lábrea, Brazilian Amazon: ‘accidental’ findings of Dirofilaria immitis infection

Abstract

Blood samples were collected from 99 domestic dogs from the urban and rural areas of the Lábrea municipality, state of Amazonas, Brazil. Canine serum samples were tested by immunofluorescence assay against Rickettsia spp., which revealed that only 3.0% (1/33) and 7.6% (5/66) of the dogs from urban and rural areas, respectively, reacted positively to at least one Rickettsia species. DNA was extracted from canine blood and tested by a battery of PCR assays targeting protozoa of the genera Babesia and Hepatozoon, and bacteria of the genera Rickettsia and Ehrlichia and family Anaplasmataceae. All samples were negative in the PCR assays targeting the genera Babesia, Hepatozoon, Ehrlichia and Rickettsia. For Anaplasmataceae, 3% (1/33) and 39.4% (26/66) of the urban and rural dogs, respectively, yielded amplicons that generated DNA sequences 100% identical to the corresponding sequence of Wolbachia endosymbiont of Dirofilaria immitis. Because of these results, all canine DNA samples were further tested in a PCR assay targeting filarial nematodes, which was positive for 18.2% (6/33) and 57.6% (38/66) urban and rural dogs, respectively. Filarial-PCR products generated DNA sequences 100% identical to D. immitis. While tick-borne infections were rare in Lábrea, D. immitis infection rates were among the highest reported in South America.Keywords: Dogs, ticks, Rickettsia, Wolbachia, Dirofilaria immitis, Amazon. ResumoAmostras de sangue foram coletadas de 99 cães domésticos de áreas urbana e rural do município de Lábrea, estado do Amazonas. Soros caninos foram testados pela técnica de imunofluorescência indireta contra Rickettsia spp., resultando em apenas 3,0% (1/33) e 7,6% (5/66) de cães soropositivos nas áreas urbana e rural, respectivamente. DNA foi extraído do sangue canino e testado por diferentes protocolos da PCR para detecção de protozoários dos gêneros Babesia e Hepatozoon, e bactérias dos gêneros Rickettsia e Ehrlichia e da família Anaplasmataceae. Todas as amostras foram negativas nos protocolos de PCR para os gêneros Babesia, Hepatozoon, Ehrlichia e Rickettsia. Para Anaplasmataceae, 3% (1/33) e 39,4% (26/66) dos cães de áreas urbana e rural, respectivamente, geraram sequências de DNA 100% idênticas ao endosimbionte Wolbachia de Dirofilaria immitis. Posteriormente, as amostras foram testadas pela PCR para nematódeos filarídeos, resultando em 18,2% (6/33) e 57,6% (38/66) de amostras positivas nas áreas urbana e rural, respectivamente. Os produtos geraram sequências de DNA 100% idênticas a D. immitis. Em contraste com várias outras regiões do Brasil, infecções transmitidas por carrapatos foram raras em Lábrea. Por outro lado, as frequências de infecção por D. immitis estiveram entre as mais altas relatadas na América do Sul.

Seroprevalence of Tick-Borne Pathogens and Tick Infestation in Dogs from Tapirapé and Karajá Indigenous Communities, Brazil

“…In contrast to a recent study with dogs from two indigenous communities in the state of Amazonas, where no dog was found to be infected by Ehrlichia or Babesia organisms (Soares et al 2014), the present study provides serological evidence of the circulation of tick-borne agents of the genera Ehrlichia and Babesia organisms among dogs from two Indian communities in the Amazon region. Whereas R. sanguineus was not present in the Indian villages of the study of Soares et al (2014), this tick species was present within the two Indian communities of the present study, providing epidemiological evidence that at least part of the seropositive dogs have been infected by E. canis and B. vogeli.…”

“…Whereas R. sanguineus was not present in the Indian villages of the study of Soares et al (2014), this tick species was present within the two Indian communities of the present study, providing epidemiological evidence that at least part of the seropositive dogs have been infected by E. canis and B. vogeli. Finally, the presence of many dogs with higher antibody titers to R. amblyommii, and infestations by A. cajennense s.s. ticks, in conjunction with the report of this Rickettsia species infecting most of the A. cajennense s.s. ticks collected from wildlife in the study area (Soares et al 2015), provides epidemiological evidence for canine infection by R. amblyommii, which is a spotted fever agent suspected to cause infection or even illness in humans (Apperson et al 2008, Blanton et al 2014.…”

“…and by molecular methods for tick-borne agents of the genera Rickettsia, Ehrlichia, Babesia, and Hepatozoon. Only a single dog in each of the communities was serologically reactive to Rickettsia spp., whereas none of the 26 dogs was found through molecular methods to be infected by tick-borne agents (Soares et al 2014).…”

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

“…uring the last two decades, there has been a substantial improvement in our knowledge regarding vector-borne agents that infect domestic dogs in Brazil (Soares et al 2014). On the other hand, most of the studies have been conducted traditionally with canine populations from more densely populated areas of Brazil, such as the southeastern and southern regions, and coastal areas of the northeastern region , Ramos et al 2010, Vieira et al 2011, Silva et al 2012, Demoner et al 2013, Santos et al 2013, Vieira et al 2013).…”

<b>Pesquisa de infecção por riquétsias do grupo da febre maculosa em cães, pequenos mamíferos e carrapatos em área endêmica e não endêmicas nos biomas Pampa e Mata Atlântica no estado do Rio Grande do Sul</b>

“…Diversos estudos sorológicos buscando analisar a frequência de anticorpos frente a antígenos de riquétsias do GFM têm sido realizados em cães no Brasil, abrangendo áreas endêmicas e não endêmicas, estudos já foram realizados em cães que habitavam áreas dos biomas, Amazônia, Caatinga, Cerrado, Mata Atlântica, Pampa e Pantanal ou seja todos os biomas no país já foram estudados (LABRUNA et al, 2007a;SAITO et al, 2008;GAZETA et al, 2009;MELO et al, 2011a;OGRZEWALSKA et al, 2012b;BARBIERI et al, 2014;SOARES et al, 2014;ARAES-SANTOS et al, 2015;SILVEIRA et al, 2015). Piranda et al (2008) (61/504) destes animais haviam tido contato com alguma espécie de riquétsia (ARAES-SANTOS et al, 2015).…”