RESUMO
Ixodes schulzei is an ixodid tick that parasitizes Cricetidae rodents, chiefly the South American water rat, Nectomys squamipes, in Brazil and Argentina. In the present study, we evaluated the life cycle of I. schulzei by exposing larvae and nymphs to feed on two rodent species, N. squamipes and Calomys callosus (large vesper mouse),while adult ticks were exposed to feed on N. squamipes. Off-host developmental periods were observed in an incubator at 27 °C, 95% relative humidity, and 0:24 (light:dark) regimen. Larvae and nymphs successfully fed on either C. callosus or N. squamipes. Mean larval and nymphal feeding periods were 8.8 and 8.7 days on N. squamipes and 8.5 and 9.7 days on C. callosus. The majority of engorged larvae (79.0-80.8%) and nymphs (67.0-86.0%) successfully molted to nymphs and adults, respectively. Mean premolt periods were 11.5-11.7 days for engorged larvae and 22.5-23.7 days for engorged nymphs. Only adult females emerged from engorged nymphs, regardless of host species, i.e., none of 120 engorged nymphs molted to male. Around 18% of the unfed females presented teratologies compatible with the metagynander type of gynandromorphism. Ixodes schulzei adult females successfully fed (mean feeding period, 9.4 days), oviposited, and presented high reproductive performance (high engorged weight, egg mass weight, and % egg mass hatching), in the absence of male ticks. Our results showed that I. schulzei successfully reproduces by parthenogenesis, and corroborate field data that indicate N. squamipes as the most important host for this tick species. The male of I. schulzei remains unknown.
Assuntos
Ixodes/crescimento & desenvolvimento , Ixodes/fisiologia , Estágios do Ciclo de Vida/fisiologia , Partenogênese/fisiologia , Animais , Argentina , Arvicolinae/parasitologia , Brasil , Feminino , Especificidade de Hospedeiro , Laboratórios , Larva/crescimento & desenvolvimento , Masculino , Camundongos , Ninfa/crescimento & desenvolvimento , Oviposição/fisiologia , Sigmodontinae/parasitologiaRESUMO
Rickettsia amblyommatis has been reported infecting various tick species throughout the western hemisphere, including Amblyomma cajennense sensu stricto (s.s.). The present study aimed to evaluate whether R. amblyommatis can be maintained by transovarial transmission and transstadial passage in A. cajennense s.s. ticks, and whether these ticks are competent vectors of this rickettsial agent. We selected engorged females that were naturally infected or uninfected by R. amblyommatis, and reared their offspring (infected and control groups, respectively). Immature ticks were allowed to feed on guinea pigs, whereas adults fed on rabbits. All stages and individuals of each generation of the infected group yielded rickettsial DNA, which was not detected in any tick from the control group. No host from the control group seroconverted to R. amblyommatis. Among 16 guinea pigs and eight rabbits infested with R. amblyommatis-infected ticks, only one guinea pig seroconverted to R. amblyommatis. Some unfed adult ticks of the infected group were dissected, and DNA was extracted from their salivary glands and from their carcasses. DNA of R. amblyommatis was detected in all carcasses, but not in the salivary glands. Results of this study indicate very low vector competence of A. cajennense s.s. for R. amblyommatis. Previous studies reported domestic animals with high titers to R. amblyommatis in areas where these animals are naturally infested chiefly by A. cajennense s.s. ticks. One may consider that the vector competence of A. cajennense s.s. for R. amblyommatis could vary among tick populations and/or rickettsial strains.
Assuntos
Vetores Artrópodes/microbiologia , Infecções por Rickettsia/veterinária , Rickettsia/isolamento & purificação , Carrapatos/microbiologia , Animais , Brasil , Feminino , Cobaias , CoelhosRESUMO
Amblyomma aureolatum ticks are vectors of Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever in Brazil. Maintenance of R. rickettsii in nature depends on horizontal transmission along tick generations. Although such transmission is known to occur when uninfected and infected ticks feed simultaneously on susceptible animals (co-feeding systemic transmission), we investigated co-feeding nonsystemic transmission, which was based on R. rickettsii-infected and -uninfected A. aureolatum ticks feeding simultaneously on guinea pigs immune to R. rickettsii. Our acquisition and transmission infestations demonstrated that horizontal transmission of R. rickettsii by co-feeding ticks on immune hosts with no systemic infection did not occur when uninfected larvae fed distantly from infected nymphs but did occur in a few cases when uninfected larvae fed side-by-side with infected nymphs, suggesting that they shared the same feeding site. The co-feeding nonsystemic transmission type might have no epidemiologic importance for Rocky Mountain spotted fever.
Assuntos
Vetores Aracnídeos/microbiologia , Ixodidae/microbiologia , Rickettsia rickettsii/fisiologia , Febre Maculosa das Montanhas Rochosas/transmissão , Animais , Brasil , Suscetibilidade a Doenças , Feminino , Cobaias , Humanos , Larva , Ninfa , Febre Maculosa das Montanhas Rochosas/microbiologiaRESUMO
Magellanic penguins (Spheniscus magellanicus) breed on the Atlantic and Pacific coasts of the southernmost parts of South America and migrate northward as far as Peru and Brazil. Serum samples (n = 100) from Magellanic penguins from three zoos and two rehabilitation centers (RCs) in Brazil were assayed for the presence of antibodies to Toxoplasma gondii by means of the modified agglutination test (MAT, cut-off ≥ 20). The penguins were categorized as young (≤4 yr old) or adults (≥4 yr old) and sexed (male, female, or not identified), and data were analyzed using the chi-square test (P ≤ 0.05). Toxoplasma gondii antibodies were found in 28% of penguins: 25.8% males, 27.8% females, 30.3% unknown sex, 25.4% young, and 31.1% adults. Statistical analyses did not find any difference (P > 0.05) with respect to age, sex, or source of birds. This is the first report of T. gondii antibodies in S. magellanicus.
Assuntos
Anticorpos Antiprotozoários/sangue , Doenças das Aves/parasitologia , Spheniscidae , Toxoplasma/imunologia , Toxoplasmose Animal/sangue , Animais , Doenças das Aves/sangue , Doenças das Aves/imunologia , Feminino , Masculino , Toxoplasmose Animal/imunologiaRESUMO
Antillean manatees ( Trichechus manatus manatus) are aquatic mammals that inhabit marine waters from Central America to the northeastern region of Brazil, and they are an endangered species. Infection with Toxoplasma gondii through intake of water or food contaminated with oocysts has been reported among marine mammals. The present study aimed to evaluate the prevalence of antibodies to T. gondii in West Indian manatees living in captivity in northeastern Brazil. Serum samples from 55 West Indian manatees from three different captive groups were tested for T. gondii antibodies by means of the modified agglutination test using a cutoff of 1:25. The samples were screened at dilutions of 1:25, 1:50, and 1:500, and positive samples were end-titrated using twofold serial dilutions; antibodies were found in six Antillean manatees (10.9%) with titers of 1:50 in three, 1:500 in one, 1:3,200 in one, and 1:51,200 in one manatee. This study is the first report of T. gondii antibodies in captive Antillean manatees in Brazil.
Assuntos
Toxoplasma/isolamento & purificação , Toxoplasmose Animal/parasitologia , Trichechus manatus/sangue , Envelhecimento , Animais , Animais de Zoológico , Brasil/epidemiologia , Feminino , Masculino , Estudos SoroepidemiológicosRESUMO
During 2009-2012, wild animals and their ticks were sampled in two areas within the Amazon biome of Brazil, in the states of Mato Grosso and Pará. Animal tissues, blood, and ticks were molecularly tested for Rickettsia and Coxiella DNA. A total of 182 wild animals were sampled, comprising 28 mammalian, five avian, and three reptilian species. Animal tissues or blood were all negative for Rickettsia or Coxiella DNA. A total of 454 ticks (22 larvae, 226 nymphs, 127 males, 79 females) were collected from 52 (28.6%) animals, and identified into 15 species: Amblyomma cajennense, A. naponense, A. humerale, A. nodosum, A. goeldii, A. oblongoguttatum, A. longirostre, A. calcaratum, A. coelebs, A. pacae, A. geayii, A. rotundatum, A. auricularium, A. ovale, and Haemaphysalis juxtakochi. While no Coxiella DNA was identified in ticks, six Rickettsia species were detected in the ticks. "Candidatus Rickettsia amblyommii" was the most common agent, detected in four tick species, A. cajennense, A. auricularium, A. longirostre, and A. humerale. The second most common agent, R. bellii, was detected in A. humerale and A. naponense. Rickettsia rhipicephali was detected in H. juxtakochi, and R. felis in A. humerale. Two possible new Rickettsia species were detected in A. naponense ticks, namely, a novel spotted fever group agent close-related to R. africae in Pará, and a novel Canadensis group agent in Mato Grosso. Results of the present study expand our knowledge on the tick fauna, and on the yet infantile knowledge of tick-borne rickettsiae in the Amazon biome.
Assuntos
Animais Selvagens/parasitologia , Infecções por Rickettsia/veterinária , Carrapatos/microbiologia , Animais , Brasil/epidemiologia , Feminino , Larva/microbiologia , Larva/fisiologia , Masculino , Ninfa/microbiologia , Ninfa/fisiologia , Infecções por Rickettsia/epidemiologia , Especificidade da Espécie , Carrapatos/fisiologiaRESUMO
Rocky Mountain spotted fever is endemic to the São Paulo metropolitan area, Brazil, where the etiologic agent, Rickettsia rickettsii, is transmitted to humans by adult Amblyomma aureolatum ticks. We determined the minimal feeding period required by A. aureolatum nymphs and adults to transmit R. rickettsii to guinea pigs. Unfed nymphs and unfed adult ticks had to be attached to the host for >10 hours to transmit R. rickettsii. In contrast, fed ticks needed a minimum of 10 minutes of attachment to transmit R. rickettsii to hosts. Most confirmed infections of Rocky Mountain spotted fever in humans in the São Paulo metropolitan area have been associated with contact with domestic dogs, the main host of A. aureolatum adult ticks. The typical expectation that transmission of tickborne bacteria to humans as well as to dogs requires ≥2 hours of tick attachment may discourage persons from immediately removing them and result in transmission of this lethal bacterium.
Assuntos
Ixodidae/microbiologia , Rickettsia rickettsii , Febre Maculosa das Montanhas Rochosas/transmissão , Animais , Vetores Artrópodes/microbiologia , Brasil/epidemiologia , Modelos Animais de Doenças , Reservatórios de Doenças/parasitologia , Cães , Feminino , Cobaias , Humanos , Ixodidae/fisiologia , Masculino , Mortalidade , Ninfa/microbiologia , Rickettsia rickettsii/isolamento & purificação , Febre Maculosa das Montanhas Rochosas/epidemiologia , Febre Maculosa das Montanhas Rochosas/mortalidadeRESUMO
Background: There are few reports of tick-borne pathogens infecting dogs living in indigenous communities of Brazil. Herein, we aimed to molecularly detect vector-borne pathogens in dogs from two indigenous communities in the Brazilian Amazon. Materials and Methods: We surveyed 327 dogs raised in Amazon region at 2 distinct indigenous ethnicities for the molecular detection of tick-borne pathogens (114 from Tapirapé and 213 from Karajá indigenous ethnicity). Whole blood samples were subjected to PCR and sequencing for Ehrlichia, Babesia, and Hepatozoon. Univariate and multivariate analyses were used to investigate the factors affecting the pathogen infection patterns in dogs. Results: Among the 327 blood samples, 40 were positive for Ehrlichia canis (12.2%), 2 for Anaplasma platys (0.61%), and 204 were positive for Hepatozoon canis (66.5%). Binary Logistic Regression showed association between E. canis infection and ethnicity (p = 0.010) and tick attachment (p = 0.041). Karajá dogs were 3.4 times (95% CI 1.3-8.5) more likely to be positive for E. canis than Tapirapé dogs. Dogs with ticks were 2.5 times more likely (95% CI 1.0-7.6) to be positive for E. canis than dogs without ticks. Conclusions: Our survey expands the knowledge regarding the presence of vector-borne pathogens in dogs from indigenous communities in the Amazon region.
Assuntos
Doenças do Cão , Ehrlichiose , Doenças Transmitidas por Carrapatos , Carrapatos , Cães , Animais , Doenças Transmitidas por Carrapatos/epidemiologia , Doenças Transmitidas por Carrapatos/veterinária , Brasil/epidemiologia , Ehrlichia/genética , Anaplasma/genética , Ehrlichia canis/genética , Doenças do Cão/epidemiologia , Ehrlichiose/epidemiologia , Ehrlichiose/veterináriaRESUMO
We investigated the biochemical profile of greater rheas (Rhea americana) in captivity and correlated these values according to the birds' sex. A total of 69 serum samples were collected from a breeding site in Mossoró, northeastern Brazil, and analyzed to quantify serum biochemical parameters (total protein, albumin, cholesterol, calcium, phosphorus, uric acid, urea, creatinine, ALP, AST, and CK). The birds had levels of urea, creatinine, total cholesterol, aspartate aminotransferase, calcium, and phosphorus similar to the values reported for ratite and ostrich species. By sex, females showed higher values (p < 0.05) of calcium (3.5 mmol/L), total cholesterol (7.5 mmol/L), and uric acid (435.3 µmol/L) than males, which had 3.1 mmol/L, 3.8 mmol/L, and 390.7 µmol/L, respectively. This can be attributed to the difference in diet, the productive phase of females, or stress at the time of sampling. The data present a wide spectrum of biochemical results regarding the health of greater rheas, contributing to the veterinary clinical practice of this species.
RESUMO
We experimentally infected Amblyomma aureolatum ticks with the bacterium Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever (RMSF). These ticks are a vector for RMSF in Brazil. R. rickettsii was efficiently conserved by both transstadial maintenance and vertical (transovarial) transmission to 100% of the ticks through 4 laboratory generations. However, lower reproductive performance and survival of infected females was attributed to R. rickettsii infection. Therefore, because of the high susceptibility of A. aureolatum ticks to R. rickettsii infection, the deleterious effect that the bacterium causes in these ticks may contribute to the low infection rates (<1%) usually reported among field populations of A. aureolatum ticks in RMSF-endemic areas of Brazil. Because the number of infected ticks would gradually decrease after each generation, it seems unlikely that A. aureolatum ticks could sustain R. rickettsii infection over multiple successive generations solely by vertical transmission.
Assuntos
Rickettsia rickettsii/fisiologia , Carrapatos/microbiologia , Animais , Cães , Feminino , Cobaias , Masculino , Coelhos , Febre Maculosa das Montanhas Rochosas/microbiologia , Febre Maculosa das Montanhas Rochosas/transmissãoRESUMO
The present study evaluated the reproductive compatibility of the crosses between adult ticks of the following three geographically different populations of Amblyomma cajennense: State of São Paulo (SP), southeastern Brazil; State of Rondônia (RO), northern Brazil; and Colombia (CO). In addition, crosses between A. cajennense ticks from Argentina (AR) and SP ticks were also performed. The Argentinean population (AR) was compatible with SP because their crosses resulted in high % egg hatching (mean values ranging from 71.5 to 93.5%), similarly to all homologous (intrapopulational) crosses. In contrast, the tick populations SP, RO, and CO were shown to be incompatible with each other, since their heterologous (interpopulational) crosses always resulted in very low % egg hatching (range: 0-5%). The F(1) larval offspring derived from some of these females that yielded 5% egg hatching were reared until the F(1) adult stage. In all cases, only adult females molted from engorged nymphs. These F(1) females were likely to be a product of thelytokous parthenogenesis of the SP, RO, and CO females that were used in the heterologous crosses. Reproductive incompatibility is not expected to occur between different populations of a single species. Thus, our results suggest that the taxon A. cajennense might be represented by a complex of different species, whereas SP and AR ticks might represent a single species. Further populational genetic studies, coupled with extensive morphological analyses, are needed to clarify and determine a possible complex of valid species that might have been classified under the taxon A. cajennense.
Assuntos
Hibridização Genética , Ixodidae/fisiologia , Animais , Brasil , Colômbia , Feminino , Geografia , MasculinoRESUMO
In this study, the occurrence of antibodies to Toxoplasma gondii in Brazilian agouti (Dasyprocta aguti) was compared by modified agglutination test (MAT) and indirect fluorescent antibody test (IFAT) using anti-capybara conjugate. Sera from 109 animals were tested using MAT (1:25 cut-off) and IFAT (1:16 cut-off); 19% were positive by MAT, and 18% were positive by IFAT. Overall, the 17 IFAT-positive samples were also positive for MAT. The four positive MAT samples with a titer < or = 200 were IFAT negative. All negative samples obtained by MAT matched with the results of the IFAT. Comparing both tests, and considering MAT as the gold standard, the sensitivity of IFAT was 81%, the specificity was 100%, the accuracy was 97%, the positive predictive value (PPV) was 100%, and the negative predictive value 96%. The kappa value agreement was 87.3% (75.1-99.6%). The anti-capybara conjugate can be successfully used to perform IFAT in Brazilian agouti with maximum specificity and PPV.
Assuntos
Testes de Aglutinação/veterinária , Anticorpos Antiprotozoários/sangue , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Doenças dos Roedores/parasitologia , Toxoplasma/imunologia , Toxoplasmose Animal/parasitologia , Animais , Brasil/epidemiologia , Valor Preditivo dos Testes , Doenças dos Roedores/sangue , Doenças dos Roedores/epidemiologia , Doenças dos Roedores/imunologia , Roedores , Sensibilidade e Especificidade , Toxoplasmose Animal/sangue , Toxoplasmose Animal/epidemiologia , Toxoplasmose Animal/imunologiaRESUMO
Armadillos are specialist diggers and their burrows are used to find food, seek shelter and protect their pups. These burrows can also be shared with dozens of vertebrate and invertebrate species and; consequently, their parasites including the zoonotics. The aim of this study was to diagnose the presence of zoonotic parasites in four wild-caught armadillo species from two different Brazilian ecosystems, the Cerrado (Brazilian savanna) and the Pantanal (wetland). The investigated parasites and their correspondent diseases were: Toxoplasma gondii (toxoplasmosis), Trypanosoma cruzi (Chagas disease), Leishmania spp., (leishmaniasis), Paracoccidioides brasiliensis (Paracoccidioidomicosis) and Mycobacterium leprae (Hansen's disease). Forty-three free-living armadillos from Pantanal and seven road-killed armadillos from the Cerrado were sampled. Trypanosoma cruzi DTU TcIII were isolated from 2 out of 43 (4.65%) armadillos, including one of them also infected with Trypanosoma rangeli. Antibodies anti-T. gondii were detected in 13 out of 43 (30.2%) armadillos. All seven armadillos from Cerrado tested positive for P. brasiliensis DNA, in the lungs, spleen, liver fragments. Also, by molecular analysis, all 43 individuals were negative for M. leprae and Leishmania spp. Armadillos were infected by T. cruzi, T. rangeli, P. brasiliensis and presented seric antibodies to T. gondii, highlighting the importance of those armadillos could have in the epidemiology of zoonotic parasites.
Assuntos
Tatus , Doença de Chagas/veterinária , Leishmaniose/veterinária , Hanseníase/veterinária , Paracoccidioidomicose/veterinária , Toxoplasmose Animal/parasitologia , Zoonoses/microbiologia , Zoonoses/parasitologia , Animais , Brasil , Doença de Chagas/parasitologia , Feminino , Leishmania/isolamento & purificação , Leishmaniose/parasitologia , Hanseníase/microbiologia , Masculino , Mycobacterium leprae/isolamento & purificação , Paracoccidioides/isolamento & purificação , Paracoccidioidomicose/parasitologia , Especificidade da Espécie , Toxoplasma/isolamento & purificação , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
Toxoplasma gondii is an obligate intracellular parasite with a variety of hosts, responsible for reproductive problems and economic losses in sheep flocks. Neospora caninum was recently identified and its clinical presentation in sheep is similar to that of toxoplasmosis, which can cause repeated abortions, though less frequently in this species. In order to confirm the prevalence of these agents in the city of Mossoró, Rio Grande do Norte, Brazil, 409 serum samples from adult sheep (364 females and 45 males) were tested by the indirect immunofluorescence antibody test, using cut-off point at a dilution of 1:64 and 1:50 for T. gondii and N. caninum, respectively. From the 35 properties examined, 23 (65.7%) had at least one seropositive animal for T. gondii and six (17.1%) for N. caninum. The prevalence of seropositive animals for T. gondii was 20.7% and for N. caninum 1.8%. There was no association between the presence of the agent's antibody and gender, reports of reproductive problems and presence of dogs and/or cats in the properties. T. gondii is well distributed and N. caninum has low prevalence in sheep and in the properties of the studied region.
Assuntos
Anticorpos Antiprotozoários/sangue , Coccidiose/veterinária , Neospora/imunologia , Doenças dos Ovinos/epidemiologia , Toxoplasma/imunologia , Toxoplasmose Animal/epidemiologia , Aborto Animal/parasitologia , Animais , Brasil/epidemiologia , Coccidiose/epidemiologia , Coccidiose/transmissão , Reservatórios de Doenças/parasitologia , Reservatórios de Doenças/veterinária , Feminino , Técnica Indireta de Fluorescência para Anticorpo/métodos , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Masculino , Gravidez , Estudos Soroepidemiológicos , Ovinos , Doenças dos Ovinos/transmissão , Toxoplasmose Animal/transmissãoRESUMO
This study evaluated the species richness and seasonal dynamics of ticks and rickettsial agents infecting ticks in the largest natural Reserve of the Cerrado biome of Brazil, the Grande Sertão Veredas National Park. During 2012-2014, a total of 9531 host-seeking ticks were collected by dry ice traps and dragging, whereas 1563 ticks were collected from small mammals, and 1186 ticks from domestic animals. Overall, the following 12 tick species were identified: Amblyomma auricularium, Amblyomma dubitatum, Amblyomma naponense, Amblyomma ovale, Amblyomma parvum, Amblyomma sculptum, Amblyomma tigrinum, Amblyomma triste, Dermacentor nitens, Rhipicephalus microplus, Rhipicephalus sanguineus sensu lato, and Ornithodoros mimon. The three most abundant tick species, A. sculptum, A. parvum, and A. triste, are likely to develop one generation per year, with adults predominating between spring and autumn, and immature ticks during autumn-winter. Small mammals seem to be important hosts for immature stages of A. parvum, and A. triste, but not for A. sculptum. Molecular analyses revealed the presence of the human pathogen Rickettsia parkeri in 10% of the A. triste ticks, whereas two agents of unknown pathogenicity, Rickettsia bellii and 'Candidatus Rickettsia andeanae' were found in 7 and 5%, respectively, of the A. parvum ticks. A fourth rickettsial agent, Rickettsia amblyommatis, was found in a single A. sculptum tick. Several Vero cell-established isolates of R. parkeri and R. bellii were obtained from A. triste and A. parvum, respectively. Serological analyses of small mammals suggest that they have been infected by R. parkeri and R. bellii, possibly via natural infestations by A. triste and A. parvum, respectively. Because the Park has suffered low anthropic alterations, our results should provide baseline data that shall be used for future comparisons with other Cerrado areas with higher degree of anthropic changes.
Assuntos
Infecções por Rickettsia/veterinária , Estações do Ano , Infestações por Carrapato/veterinária , Carrapatos/microbiologia , Animais , Animais Domésticos/microbiologia , Animais Domésticos/parasitologia , Animais Selvagens/microbiologia , Animais Selvagens/parasitologia , Brasil/epidemiologia , Bovinos , Cães , Ecossistema , Cavalos , Larva/microbiologia , Mamíferos/parasitologia , Ninfa/microbiologia , Parques Recreativos , Rickettsia/isolamento & purificação , Infecções por Rickettsia/epidemiologia , Infestações por Carrapato/epidemiologiaRESUMO
During 2009-2012, wild animals were sampled in the Amazon biome of Brazil. Animal tissues and blood were tested by polymerase chain reaction (PCR) assays targeting DNA of the bacterial family Anaplasmataceae (genera Anaplasma, Ehrlichia, Wolbachia) and the genus Borrelia. Overall, 181 wild animals comprising 36 different species (2 reptiles, 5 birds, and 29 mammals) were sampled. All birds and reptiles were negative by all PCR assays, as well as all mammals for the Borrelia PCR assay. Anaplasmataceae agents were searched by PCR assays targeting two different genes, the ribosomal 16S rRNA gene and the protein-coding dsb gene. Three dsb closely related haplotypes were generated from 3 white-lipped peccaries (Tayassu pecari). In a phylogenetic analysis inferred from dsb partial sequences, these haplotypes grouped with previously reported Ehrlichia haplotypes from jaguar (Panthera onca) and horse from Brazil, suggesting that they could all represent a single species, yet to be properly characterized. A unique dsb haplotype was generated from a sloth (Bradypus tridactylus), and could also represent a different Ehrlichia species. All these dsb haplotypes formed a clade sister to the Ehrlichia ruminantium clade. Three distinct 16S rRNA gene haplotypes were generated from a wild guinea pig (Cavia sp.), a woolly mouse opossum (Micoureus demerarae), and two from robust capuchin monkeys (Sapajus sp.). In a phylogenetic analysis inferred from 16S rRNA gene partial sequence, these haplotypes grouped within the Wolbachia clade, and are likely to represent Wolbachia organisms that were infecting invertebrate metazoarians (e.g., filarids) associated with the sampled mammals. Two deer (Mazama americana) samples yielded two distinct 16S rRNA gene sequences, one identical to several sequences of Anaplasma bovis, and an unique sequence that grouped in a clade with different Anaplasma species. Our results indicate that a variety of genetically distinct Anaplasmataceae organisms, including potentially new Ehrlichia species, circulate under natural conditions in the Amazonian wildlife.
Assuntos
Anaplasma/genética , Anaplasma/isolamento & purificação , Animais Selvagens/microbiologia , Ehrlichia/genética , Ehrlichia/isolamento & purificação , Animais , Brasil , Variação Genética , Geografia , Filogenia , RNA Ribossômico 16S/genéticaRESUMO
During 2009-2012, wild animals were sampled in two areas within the Amazon biome of Brazil, in the states of Mato Grosso and Pará. Animal tissues and blood were molecularly tested for the presence of Piroplasmida (genera Babesia, Theileria, Cytauxzoon) or Hepatozoon DNA. Overall, 181 wild animals comprising 36 different species (2 reptiles, 5 birds, and 29 mammals) were sampled. The following Piroplasmida agents were detected: Cytauxzoon felis in one ocelot (Leopardus pardalis), Theileria cervi in two red brocket deer (Mazama americana), Theileria spp. in three nine-banded-armadillos (Dasypus novemcinctus), one agouti (Dasyprocta sp.), and four lowland pacas (Cuniculus paca), Babesia spp. in one common opossum (Didelphis marsupialis) and one white-lipped peccary (Tayassu pecari). The following Hepatozoon agents were detected: Hepatozoon sp. (possibly Hepatozoon caimani) in three spectacled caimans (Caiman crocodilus), Hepatozoon felis in an ocelot (Leopardus pardalis), and Hepatozoon spp. in one scorpion mud turtle (Kinosternon scorpioides) and one lowland paca (Cuniculus paca). Phylogenetic analyses inferred by the 18S rRNA gene partial sequences supported these results, highlighting at least five novel Piroplasmida agents, and two novel Hepatozoon agents. This study screened the presence of tick-borne protozoa in a number of wildlife species from the Amazon for the first time. Our results indicate that a variety of genetically distinct Piroplasmida and Hepatozoon organisms circulate under natural conditions in the Amazonian wildlife.
RESUMO
This study was performed in Maranhão state, a transition area two Brazilian biomes, Amazon and Cerrado. During 2011-2013, 1,560 domestic dogs were sampled for collection of serum blood samples and ticks in eight counties (3 within the Amazon and 5 within the Cerrado). A total of 959 ticks were collected on 150 dogs (9.6%). Rhipicephalus sanguineus sensu lato (s.l.) was the most abundant tick (68% of all collected specimens), followed by Amblyomma cajennense sensu lato (s.l.) (12.9%), Amblyomma parvum (9.2%), and Amblyomma ovale (5.2%). Other less abundant species (<1%) were Amblyomma oblongoguttatum, Rhipicephalus microplus, Haemaphysalis juxtakochi, and Amblyomma rotundatum. Females of A. cajennense s.l. ticks were morphologically identified as A. cajennense sensu stricto (s.s.) or A. sculptum. Molecular analyses of 779 canine ticks revealed three Rickettsia species: Rickettsia amblyommatis in 1% (1/100) A. cajennense s.l., 'Candidatus Rickettsia andeanae' in 20.7% (12/58) A. parvum, Rickettsia bellii in 6.8% (3/44) A. ovale and 100% (1/1) A. rotundatum ticks. An additional collection of A. sculptum from horses in a Cerrado area, and A. cajennense s.s. from pigs in an Amazon area revealed R. amblyommatis infecting only the A. cajennense s.s. ticks. Serological analysis of the 1,560 canine blood samples revealed 12.6% canine seroreactivity to Rickettsia spp., with the highest specific seroreactivity rate (10.2%) for R. amblyommatis. Endpoint titers to R. amblyommatis were significantly higher than those for the other Rickettsia antigens, suggesting that most of the seroreactive dogs were exposed to R. amblyommatis-infected ticks. Highest canine seroreactivity rates per locality (13.1-30.8%) were found in Amazon biome, where A. cajennense s.s. predominated. Lowest seroreactivity rates (1.9-6.5%) were found in Cerrado localities that were further from the Amazon, where A. sculptum predominated. Multivariate analyses revealed that canine seroreactivity to Rickettsia spp. or R. amblyommatis was statistically associated with rural dogs, exposed to Amblyomma ticks.
Assuntos
Infecções por Rickettsia/microbiologia , Infecções por Rickettsia/parasitologia , Rickettsia/fisiologia , Carrapatos/microbiologia , Animais , Brasil , Cães , Determinação de Ponto Final , Feminino , Imunofluorescência , Geografia , Modelos Logísticos , Masculino , Análise Multivariada , Razão de Chances , Rickettsia/isolamento & purificação , Infecções por Rickettsia/epidemiologia , Fatores de Risco , População Rural/estatística & dados numéricos , Estudos Soroepidemiológicos , População Urbana/estatística & dados numéricosRESUMO
BACKGROUND: Rickettsia rickettsii, the etiological agent of Rocky Mountain spotted fever, is transmitted to humans by ticks. During tick feeding, R. rickettsii is exposed to both temperature elevation and components of the blood meal, which have previously been associated with the reactivation of its virulence. These environmental stimuli were also reported to modulate virulence genes of R. rickettsii infecting a set of organs of adult females of its natural vector, Amblyomma aureolatum. METHODS: In this study, we determined the effects of a temperature upshift, blood-feeding, and both stimuli simultaneously on the expression of 85 selected genes of R. rickettsii infecting either the midgut (MG) or salivary glands (SG) of male and female A. aureolatum by microfluidic high-throughput RT-qPCR. These two organs are key for acquisition of this bacterium by the tick and transmission to the vertebrate host, respectively. RESULTS: Data showed that these environmental stimuli exert distinct effects on rickettsial transcription depending on the colonized organ and gender of the vector. Temperature upshift induced the majority of differentially expressed genes of R. rickettsii in tick SG, including tRNA synthetases encoding genes. On the contrary, blood-feeding downregulated most of differentially expressed genes in both organs, but induced type IV secretion system components and OmpB in tick MG. The combined effects of both stimuli resulted in a merged gene expression profile representing features of each stimulus analyzed independently, but was more similar to the profile induced by blood-feeding. CONCLUSION: The upregulation of the majority of differentially expressed genes in tick SG by temperature upshift suggests that this stimulus is important to prepare R. rickettsii for transmission to the vertebrate host. Blood-feeding, on the other hand, induced important virulence genes in the tick MG, which might be associated with colonization of the tick and transmission to the vertebrate host. The role of the proteins identified in this study must be addressed and might help to define future targets to block tick infection, thereby preventing RMSF. To our knowledge, this is the first transcriptional tissue-specific study of a virulent strain of R. rickettsii infecting a natural tick vector.
Assuntos
Trato Gastrointestinal/microbiologia , Regulação Bacteriana da Expressão Gênica/fisiologia , Ixodidae/microbiologia , Rickettsia rickettsii/fisiologia , Temperatura , Animais , Comportamento Alimentar , Feminino , Interações Hospedeiro-Patógeno , Ixodidae/fisiologia , Masculino , Rickettsia rickettsii/genética , Virulência/genéticaRESUMO
Toxoplasma gondii is a coccidian parasite that infects almost all warm-blooded animals, including birds. Abrolhos is an archipelago of five islands, located in the Atlantic Ocean, 56 nautical kilometers from the south coast of the state of Bahia, northeastern Brazil. Part of this archipelago is a National Marine Park, which is a conservation area protected by the Brazilian government. The objective of this study was to determine the occurrence of T. gondii antibodies in sera of seabird's species Sula spp. and Phaeton spp. from breeding colonies located in the Islands of Santa Bárbara and Redonda, Abrolhos's archipelago. Sera were tested by modified agglutination test, first screened at 1:5 dilution (cut-off point) and the positive samples were titrated at a two-fold serial dilution. Serum samples were obtained from 69 birds of four species: Sula dactylatra (23 birds), Sula leucogaster (19 birds), Phaeton aethereus (25 birds) and Phaeton lepturus (2 birds). Antibodies to T. gondii were found in 24 (34.8%) of 69 seabirds with titers that ranged from 5 to 640. Occurrence value in S. dactylatra was 34.8% (8/23), in S. leucogaster was 47.4% (9/19), in P. aethereus was 28% (7/25) and the 2 P. lepturus were negative. This is the first description of T. gondii antibodies in free ranging seabirds of the orders Suliformes and Phaethontiformes.