Intracellular Pathogens Research Laboratory, Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina 27606, USA.
For many vector-borne organisms, dogs can be used as sentinels to estimate the risk of human infection. The objective of this study was to use dogs as sentinels for multiple vector-borne organisms in order to evaluate the potential for human infection with these agents in southeastern Brazil. Blood from 198 sick dogs with clinicopathological abnormalities consistent with tick-borne infections were selected at the São Paulo State University Veterinary Teaching Hospital in Botucatu and tested for DNA and/or antibodies against specific vector-borne pathogens. At least one organism was detected in 88% of the dogs, and Ehrlichia canis DNA was amplified from 78% of the blood samples. Bartonella spp. seroreactivity was found in 3.6%. Leishmania chagasi antibodies were detected in 1% of the dogs. There was no serological or polymerase chain reaction evidence of infection with Anaplasma phagocytophilum, Borrelia burgdorferi, Ehrlichia chaffeensis, Ehrlichia ewingii, and Rickettsia rickettsii. The full E. canis 16S rRNA gene sequence of one of the Brazilian strains obtained in this study was identical to the causative agent of human ehrlichiosis in Venezuela. Ehrlichia canis may pose a human health hazard and may be undiagnosed in southeastern Brazil, whereas exposure to the other organisms examined in this study is presumably infrequent.
"However, the increased prevalence of L. infantum in dogs would cause local outbreak of ZVL in these regions, and eradication of dogs can markedly reduce the number of human cases . Therefore, the prevalence of L. infantum infection in dogs would show trends of ZVL in humans [11,28,29]. In this study we collected blood samples from dogs in endemic areas of Wenchuan, Heishui and Jiuzhaigou County, China and evaluated the prevalence of L. infantum infection in these dogs by real time PCR "
[Show abstract][Hide abstract] ABSTRACT: Visceral leishmaniasis (VL) is endemic in western China, and becoming an important public health concern. Infected dogs are the main reservoir for Leishmania infantum, and a potential sentinel for human VL in endemic areas. In the present study we investigated the prevalence of Leishmania DNA in dogs from Wenchuan, Heishui and Jiuzhaigou County in Sichuan Province, southwestern China, which are important endemic areas of zoonotic VL, detected by real time PCR. The results will help to design control strategies against visceral leishmaniasis in dogs and humans.
The overall prevalence of Leishmania DNA in dogs was 24.8% (78/314) in Sichuan Province, with the positive rate of 23.5% (23/98) in Wenchuan County, 28.2% (20/71) in Heishui County, and 24.1% (35/145) in Jiuzhaigou County, and no significant difference was observed among the three counties (P > 0.05). The dogs were further allocated to different groups based on sexes, ages and external clinical symptoms. The logistic regression analysis revealed that a higher prevalence was found in older and external symptomatic dogs, compared to that of younger and asymptomatic dogs (P < 0.05).
The results revealed that L. infantum infection in dogs is widespread in Sichuan Province, southwestern China, which has a public health significance, due to its contribution to the transmission of the infection to humans by sandflies. It is necessary to take measures, including treatment or eradication of infected dogs, to control canine leishmaniasis, which could be helpful to reduce human VL in this area.
"Molecular diagnostic methods allow direct detection of these etiologic agents and sequence analysis facilitates their comparison to geographically diverse strains. To our knowledge, genetic and phylogenetic information about Anaplasmataceae agents in Brazil is limited (DAGNONE et al., 2003; BULLA et al., 2004; DE PAIVA DINIZ et al., 2007; NAKAGHI et al., 2008; MACIEIRA et al., 2005; HEADLEY et al., 2006; LABRUNA et al., 2007; AGUIAR et al., 2008; CARVALHO et al., 2008; SANTOS et al., 2009; CARDOZO et al., 2009; OLIVEIRA et al., 2009). Although E. canis DNA has been detected in dogs of many Brazilian states, phylogenetic analysis of Anaplasmataceae agents has not been performed in dogs from any part of the country. "
[Show abstract][Hide abstract] ABSTRACT: Ehrlichioses are important emerging zoonotic tick-borne diseases that can affect both animals and humans. Clinical manifestations of ehrlichiosis caused by different members of Anaplasmataceae in dogs are similar to each other and to other diseases showing systemic manifestation. The observation of inclusions in white blood cells and in platelets cannot be used to confirm the Anaplasmataceae etiologic agent of the disease. In this work we assessed the presence of Anaplasmataceae agents in 51 dogs from two different cities (Jaboticabal and Campo Grande) showing clinical and microscopical diagnosis of ehrlichiosis, by using molecular techniques. Anaplasmataceae DNA were amplified in 46/51 (90.2%) of the blood samples; 22 (40%) samples from Jaboticabal and 10 (18.2%) from Campo Grande were positive for E. canis nPCR. Anaplasma platys DNA was amplified in 2 samples from Jaboticabal and in 11 from Campo Grande. Phylogenetic analysis of E. canis and A. platys DNA confirmed the infection agent and showed that PCR is the most reliable method to diagnose ehrlichial infection.
Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria 12/2009; 18(4):20-5. DOI:10.4322/rbpv.01804004 · 0.87 Impact Factor
"On the contrary, human serums, taken from feverish patients and healthy blood donors, tested negative for E. canis and E. chaffeensis, despite the proved presence and the high density of the arthropod vector, Rhipicephalus . Recent studies carried out in Brazil on haemorrhagic and thrombocytopenic dogs revealed an elevated incidence of E. canis infections, but also the presence of Babesia and Anaplasma platys , and in the south-east (Saõ Paolo) a study on a group of dogs showed an 80% positivity to PCR for E. canis . An intense circulation of E. canis was found in Thailand and in Cameroon, revealing a considerable circulation of strains of E. canis but also of E. ewingii, identical in the genetic sequence to North American strains   . "
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