Tick-borne pathogens in dogs, wild small mammals and their ectoparasites in the semi-arid Caatinga biome, northeastern Brazil.

Caatinga is a biome exclusive to the semiarid zone of Brazil, where studies on ticks and tick-borne diseases are scarce. Herein, we investigated the occurrence of Rickettsia, Ehrlichia, and Coxiella in wild mammals, domestic dogs and their ectoparasites using molecular and serological techniques. During 2014-2016, blood samples and ectoparasites were collected from 70 small mammals (51 rodents, 18 marsupials, 1 wild canid) and 147 domestic dogs in three areas of the Caatinga. Through serological analyses of domestic dogs of the three areas, 8 to 11 % were seropositive for Rickettsia rickettsii, 9 to 37 % for Rickettsia amblyommatis, 61 to 75 % for Ehrlichia canis, and 0-5% for Coxiella burnetii. All wild mammals were seronegative for Rickettsia spp. and C. burnetii, except for one rodent (Wiedomys pyrrhorhinos) and one marsupial (Didelphis albiventris) that were seroreactive to C. burnetii, one wild canid (Cerdocyon thous) for R. amblyommatis, and two Rattus rattus for Rickettsia spp. Through PCR targeting DNA of Rickettsia, Ehrlichia or Coxiella, all blood samples were negative, except for the presence of Ehrlichia canis DNA in 8.8 % of the domestic dogs, and a recently reported novel agent, Ehrlichia sp. strain Natal, in one marsupial (Gracilinanus agilis). A total of 222 ticks, 84 fleas, and six lice were collected. Ticks were mostly Rhipicephalus sanguineus sensu lato, some Ixodes loricatus, Ornithodoros rietcorreai, Haemaphysalis sp., and Amblyomma spp.; fleas were Ctenocephalides felis felis, Pulex sp. and Polygenis (Polygenis) bohlsi jordani; and lice were Polyplax sp. and Gyropus sp. Through molecular detection of microorganisms, 9% of C. felis felis contained Rickettsia felis, 20 % of A. auricularium contained R. amblyommatis and 13 % of A. parvum contained 'Candidatus Rickettsia andeanae', whereas Ehrlichia canis DNA was detected in at least 6% of the R. sanguineus s.l. from one area. We report a variety of ectoparasites infesting small mammals and domestic dogs in the Caatinga biome, where these ectoparasites probably act as vectors of rickettsiae, ehrlichial agents (E. canis and Ehrlichia sp. strain Natal) and C. burnetii. Our results highlight to the potential risks of human infection by these tick-borne agents in the Caatinga biome.

New Genotypes of Coxiella burnetii Circulating in Brazil and Argentina.

Coxiella burnetii, the zoonotic agent of Q fever, has a worldwide distribution. Despite the vast information about the circulating genotypes in Europe and North America, there is a lack of data regarding C. burnetii strains in South America. Here, we show the presence of novel multispacer sequence typing (MST) genotypes of C. burnetii in two clusters detected in Brazil and Argentina that seem to be distant in parenthood. Argentinian strains isolated from a tick belongs to a new phylogenetic branch of C. burnetii, and the Brazilians strains may be related to MST 20 and 61. Multilocus variable number tandem repeats analysis (MLVA) typing provided a deeper resolution that may be related to host clusters of bovines, caprine, ovine, and ticks. Our results corroborate with the reports of geotypes of C. burnetii. Thus, we highlight the need for more genotyping studies to understand the genetic diversity of C. burnetii in South America and to confirm the hypothesis of host-related genotypes. We also emphasize the importance of virulence studies for a better understanding of Q fever in the region, which may help in surveillance and disease prevention programs.

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

Abstract The aims of our study was to identify Ehrlichia canis and antibodies against Rickettsia spp. belonging to the spotted fever group (SFG) in dogs sampled from Paraiba state, northeastern Brazil. Blood and serum samples collected by convenience from dogs in urban areas of five municipalities were analyzed by real-time PCR for the detection of E. canis DNA and by immunofluorescence assay test (IFAT) for the identification of antibodies against Rickettsia rickettsii, R. felis, R. parkeri, R. amblyommii and R. rhipicephali antigens. E. canis DNA was detected in 8.9% (64/719) of the blood samples, whereas 5.63% (43/763) of the serum samples were positive for at least one of the Rickettsia antigens tested by IFAT. This study showed for the first time the occurrence of E. canis and suggested the circulation of SFG Rickettsia in dogs in the study region of Paraiba state, northeastern Brazil.

Resumo Os objetivos do nosso estudo foram identificar Ehrlichia canis e anticorpos contra Rickettsia spp. pertencentes ao Grupo da Febre Maculosa (GFM) em cães amostrados no estado da Paraíba, nordeste do Brasil. As amostras de sangue e soro, coletados por conveniência, de cães em áreas urbanas de cinco municípios foram analisadas por PCR em tempo real para a detecção de DNA de E. canis e pela Reação de Imunofluorescência Indireta (RIFI) para identificação de anticorpos contra Rickettsia rickettsii, R. felis, R. parkeri, R. amblyommii e R. rhipicephali. O DNA de E. canis foi detectado em 8,9% (64/719) das amostras de sangue, enquanto que 5,63% (43/763) das amostras de soro foram positivas para pelo menos um dos antígenos de Rickettsia testados por RIFI. Este estudo mostrou pela primeira vez a ocorrência de E. canis e sugere a circulação de Rickettsia do GFM em cães na região em estudo do estado da Paraíba, Nordeste do Brasil.

Litomosoides silvai (Nematoda: Onchocercidae) parasitizing Akodon montensis (Rodentia: Cricetidae) in the southern region of Brazil

Abstract In the present study, Litomosoides silvai parasitizing Akodon montensis in the southern region of Brazil is reported for the first time. New morphological information is provided for some structures of this nematode species, such as a flattened cephalic extremity, presence of two dorsal cephalic papillae, female tail with a constriction at its tip, s shaped vagina, spicules characteristic of the carinii species group and microfilaria tail constricted at the tip. This nematode was found parasitizing the thoracic cavity with a prevalence of 10% (2/20), mean intensity of 4 (6/2), mean abundance of 0.4 (8/20) and range of infection of 2-6 specimens per host, in southern Brazil. This occurrence of L. silvai in A. montensis is a new geographical record for southern Brazil, in the Upper Paraná Atlantic Forest ecoregion of the northwestern region of Rio Grande do Sul, which is part of the Atlantic Forest biome.

Resumo No presente estudo é relatado pela primeira vez Litomosoides silvai parasitando Akodon montensis coletados na região Sul do Brasil. Foram fornecidas novas informações morfológicas para algumas estruturas desta espécie de nematódeo, tais como extremidade cefálica achatada, a presença de duas papilas cefálicas dorsais, cauda das fêmeas com uma constrição na ponta da cauda, vagina em forma de s, espículas de característica do grupo de espécies de carinii e cauda da microfilária com constrição na ponta. Este nematódeo parasitava a cavidade torácica com uma prevalência de 10% (2/20), intensidade média de 4 (8/2) e abundância média de 0,4 (8/20), e intervalo de infecção de 2-6 espécimes por hospedeiro no Sul do Brasil. A ocorrência de L. silvai em A. montensis é um novo registro geográfico, no sul do Brasil, a noroeste do estado do Rio Grande do Sul, na ecorregião da Mata Atlântica do Alto Paraná, parte do bioma da Mata Atlântica.

Toxoplasma gondii antibodies in wild rodents and marsupials from the Atlantic Forest, state of São Paulo, Brazil

Toxoplasma gondii is a protozoan parasite that infects a large spectrum of warm-blooded animals, including humans. Small rodents and marsupials play an important role in the epidemiology of T. gondii because they are sources of infection for domestic and feral cats. Serum samples from 151 rodents and 48 marsupials, captured in the Atlantic Forest, São Paulo State, southeastern Brazil, were analyzed for the presence of T. gondii antibodies. Antibodies detected by the modified agglutination test (MAT 25) were found in 8.6% (13/151) of the rodents and 10.4% (5/48) of the marsupials, with titers ranging from 25 to 6400 and from 25 to 3200, respectively for the rodents and marsupials. Three of the eight species of rodents (Akodon spp., Oligoryzomys nigripesand Rattus norvegicus), and one from the four marsupial species (Didelphis aurita) presented positive animals. T. gondii was described for the first time in the rodent Oligoryzomys nigripes.

Toxoplasma gondii é um protozoário parasita que infecta animais de sangue quente, incluindo seres humanos. Pequenos roedores e marsupiais têm papel importante na epidemiologia do T. gondii, pois são fontes de infecção para os felídeos domésticos e selvagens. Amostras de soro de 151 roedores e 48 marsupiais, capturados na Mata Atlântica, Estado de São Paulo, Sudeste do Brasil, foram analisadas para a pesquisa de anticorpos anti-T. gondii. Os anticorpos foram detectados pelo Teste de Aglutinação Modificada (MAT 25), com 8,6% (13/151) dos roedores e 10,4% (5/48) dos marsupiais soropositivos, com títulos variando de 25 a 6.400 e de 25 a 3.200, respectivamente, para os roedores e os marsupiais. Três das oito espécies de roedores (Akodon spp., Oligoryzomys nigripes e Rattus norvegicus) e uma das quatro espécies de marsupiais (Didelphis aurita) apresentaram animais positivos. A presença de anticorpos anti-T. gondii foi descrita pela primeira vez no roedor Oligoryzomys nigripes.

Recombinant gp19 as a potential antigen for detecting anti-Ehrlichia canis antibodies in dog sera / gp19 recombinante como um antígeno potencial para detecção de anticorposanti-Ehrlichia canis em soros de cães

The canine monocytic ehrlichiosis, caused by Ehrlichia canis, is endemic in several regions of Brazil. Some serological diagnostic techniques using immunodominant proteins of E. canis as antigens are available, but their specificities and sensitivities are questionable. Based on this, the objective of this study was to test the antigenic potential of the recombinant gp19 protein (rGP19) for subsequent use in diagnostic tests. The rGP19 expressed in the Escherichia coli strain BL21 (DE3) C41 was recognized in the sera from experimentally infected dogs using ELISA and Western blotting. Thus, it was possible to obtain a promising antigen with the ability to differentiate between E. canis-positive and -negative animals, even 1 week after infection.

A erliquiose monocítica canina, causada por Ehrlichia canis, é uma doença endêmica em diversas regiões do Brasil. Algumas técnicas de diagnóstico sorológico, utilizando proteínas imunodominantes de E. canis como antígenos, estão disponíveis, porém suas especificidades e sensibilidades são questionáveis. Com base nesse fato, o objetivo deste trabalho foi testar o potencial antigênico da proteína GP19 recombinante (rGP19) para posterior utilização em testes diagnósticos. A rGP19, expressa em E. coli cepa BL21 (DE3) C41, foi reconhecida por soros de cães experimentalmente infectados pelas técnicas de ELISA e Western blotting. Dessa maneira, conseguiu-se obter um antígeno promissor com a capacidade de diferenciar animais positivos de negativos, até mesmo uma semana após a infecção.