RESUMO
Abstract Host infection by parasites is influenced by an array of factors, including host and environmental features. We investigated the relationship between host sex, body size and age, as well as seasonality on infection patterns by acanthocephalan in coatis (Procyonidae: Nasua nasua) and in crab-eating foxes (Canidae: Cerdocyon thous ) from the Brazilian Pantanal wetlands. Between 2006 and 2009, we collected faecal samples from these hosts and analyzed for the presence of acanthocephalan eggs. Prevalence, abundance and intensity of eggs of acanthocephalans were calculated. Egg abundance was analyzed using generalized linear models (GLM) with a negative binomial distribution and models were compared by Akaike criteria to verify the effect of biotic and abiotic factors. Prevalence of acanthocephalans was higher in the wet season in both host species but did not differ between host sexes; however, adult crab-eating foxes showed higher prevalence of acanthocephalan eggs than juveniles. In contrast, prevalence of acanthocephalan eggs found in coatis was higher in coati juveniles than in adults. Host age, season and maximum temperature were the top predictors of abundance of acanthocephalan eggs in crab-eating foxes whereas season and host sex were predictors of egg abundance in coatis. The importance of seasonality for abundance of acanthocephalan was clear for both host species. The influence of host-related attributes, however, varied by host species, with host gender and host age being important factors associated with prevalence and parasite loads.
Resumo A infecção de hospedeiro por parasitos é influenciada por uma série de fatores, incluindo características do hospedeiro e ambientais. Nós investigamos a relação entre sexo do hospedeiro, tamanho corporal e idade, bem como sazonalidade nos padrões de infecção por acantocéfalos em coatis (Procyonidae: Nasua nasua) e em cachorro-do-mato (Canidae: Cerdocyon thous ) do Pantanal brasileiro e quais fatores explicaram melhor a prevalência e a intensidade desses parasitos. Entre 2006 e 2009, coletamos amostras fecais desses hospedeiros e analisamos a presença de ovos de acantocéfalos. Prevalência, abundância e intensidade de ovos de acantócefálios foram calculados. A abundância de ovos foi analisada utilizando modelos lineares generalizados (GLM) com distribuição binomial negativa e os modelos foram comparados pelo critério de Akaike para verificar o efeito de fatores bióticos e abióticos. A prevalência de acantocéfalos foi maior na estação úmida em ambas as espécies de hospedeiros, mas não diferiu entre os sexos do hospedeiro; no entanto, os cachorros-do-mato adultos apresentaram maior prevalência de ovos de acantocéfalos do que em juvenis. Em contraste, a prevalência de ovos de acantocéfalos encontrados em coatis foi maior em juvenis do que em adultos. A idade do hospedeiro, a estação e a temperatura máxima foram os preditores de abundância de ovos de acantocéfalos em cachorro-do-mato, enquanto a estação e o sexo do hospedeiro foram preditores da abundância dos ovos do parasito em coatis. A importância da sazonalidade para a abundância do acantocéfalo foi clara para ambas as espécies hospedeiras. A influência dos atributos relacionados ao hospedeiro, no entanto, variou entre as espécies de hospedeiros, sendo o sexo e idade do hospedeiro fatores importantes associados à prevalência e às cargas parasitárias.
Assuntos
Animais , Masculino , Feminino , Procyonidae , Acantocéfalos/fisiologia , Raposas , Helmintíase Animal/epidemiologia , Estações do Ano , Brasil/epidemiologia , Prevalência , Densidade Demográfica , Helmintíase Animal/parasitologiaRESUMO
Hepatozoon spp. are Apicomplexan protozoa that parasitize a wide diversity of vertebrate hosts. In Brazil, few studies have reported the occurrence of Hepatozoon spp. in rodent species. Additionally, an evaluation of the population structure and distribution of Hepatozoon species over several Brazilian biomes has not yet been performed. The present work aimed to investigate the genetic diversity of Hepatozoon spp. in rodents from 31 genera sampled in five Brazilian biomes. Samples were submitted to PCR assays for Hepatozoon spp. targeting two regions of the 18S rRNA gene. Infection by Hepatozoon spp. was detected in 195 (42.2%) rodents comprising 24 genera. Phylogenetic analyses of 18S rRNA sequences grouped all sequences in the clade of Hepatozoon spp. previously detected in rodents and reptiles, apart from those detected in domestic/wild carnivores. These data raise two non-exclusive hypotheses: (i) rodents play an important role as intermediate or paratenic hosts for Hepatozoon infections in reptiles; and (ii) rodents do not seem to participate in the epidemiology of Hepatozoon infections of domestic/wild canids and felids in Brazil. TCS analyses performed with available 18S rRNA Hepatozoon sequences detected in rodents from Brazil showed the occurrence of six haplotypes, which were distributed in two large groups: one from rodents inhabiting the coastal region of Brazil and Mato Grosso state, and another from rodents from the central region of the country. A wide survey of the South American territory will help to elucidate the evolutionary history of Hepatozoon spp. parasitizing Rodentia in the American continent.
Assuntos
Apicomplexa/genética , Variação Genética , Roedores/parasitologia , Animais , Apicomplexa/patogenicidade , Brasil , Carnívoros/parasitologia , Haplótipos , Filogenia , Infecções Protozoárias em Animais/parasitologia , RNA Ribossômico 18SRESUMO
Host infection by parasites is influenced by an array of factors, including host and environmental features. We investigated the relationship between host sex, body size and age, as well as seasonality on infection patterns by acanthocephalan in coatis (Procyonidae: Nasua nasua) and in crab-eating foxes (Canidae: Cerdocyon thous ) from the Brazilian Pantanal wetlands. Between 2006 and 2009, we collected faecal samples from these hosts and analyzed for the presence of acanthocephalan eggs. Prevalence, abundance and intensity of eggs of acanthocephalans were calculated. Egg abundance was analyzed using generalized linear models (GLM) with a negative binomial distribution and models were compared by Akaike criteria to verify the effect of biotic and abiotic factors. Prevalence of acanthocephalans was higher in the wet season in both host species but did not differ between host sexes; however, adult crab-eating foxes showed higher prevalence of acanthocephalan eggs than juveniles. In contrast, prevalence of acanthocephalan eggs found in coatis was higher in coati juveniles than in adults. Host age, season and maximum temperature were the top predictors of abundance of acanthocephalan eggs in crab-eating foxes whereas season and host sex were predictors of egg abundance in coatis. The importance of seasonality for abundance of acanthocephalan was clear for both host species. The influence of host-related attributes, however, varied by host species, with host gender and host age being important factors associated with prevalence and parasite loads.
Assuntos
Acantocéfalos/fisiologia , Canidae/parasitologia , Helmintíase Animal/epidemiologia , Procyonidae , Animais , Brasil/epidemiologia , Feminino , Helmintíase Animal/parasitologia , Masculino , Densidade Demográfica , Prevalência , Procyonidae/parasitologia , Estações do AnoRESUMO
This paper describes the diversity of rodent fauna in an area endemic for hantavirus cardiopulmonary syndrome (HCPS) in Brazil, the population dynamics and the relationship of rodents with hantavirus in the Cerrado (savanna-like) biome. Additionally, an analysis is made of the partial S segment sequences of the hantaviruses obtained from serologically confirmed human HCPS cases and from rodent specimens. Rodents were collected during four campaigns. Human serum samples were collected from suspected cases of HCPS at hospitals in the state of Minas Gerais. The samples antibody-reactive by ELISA were processed by RT-PCR. The PCR product was amplified and sequenced. Hantavirus was detected only in Necromys lasiurus, the wild rodent species most prevalent in the Cerrado biome (min-max: 50-83·7%). All the six human serum samples were hantavirus seropositive and five showed amplified PCR products. The analysis of the nucleotide sequences showed the circulation of a single genotype, the Araraquara hantavirus. The environmental changes that have occurred in the Cerrado biome in recent decades have favoured N. lasiurus in interspecific competition of habitats, thus increasing the risk of contact between humans and rodent species infected with hantavirus. Our data corroborate the definition of N. lasiurus as the main hantavirus reservoir in the Cerrado biome.
Assuntos
Reservatórios de Doenças/veterinária , Síndrome Pulmonar por Hantavirus/veterinária , Orthohantavírus/fisiologia , Doenças dos Roedores/epidemiologia , Roedores , Adulto , Animais , Brasil/epidemiologia , Feminino , Genótipo , Pradaria , Orthohantavírus/genética , Síndrome Pulmonar por Hantavirus/epidemiologia , Síndrome Pulmonar por Hantavirus/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Filogenia , Dinâmica Populacional , Prevalência , Doenças dos Roedores/virologia , Roedores/fisiologia , Análise de Sequência de DNA , Estudos Soroepidemiológicos , Proteínas Virais/genética , Proteínas Virais/metabolismo , Adulto JovemRESUMO
Since 1999, vesicular infections caused by Orthopoxvirus in humans and animals, mainly in dairy cattle, have been identified in 20 municipalities in the Rio de Janeiro state of Brazil. This paper describes studies conducted in counties of the northwestern, middle-Paraíba Valley and southern regions of the Rio de Janeiro state where 77 human, 346 bovine and 78 rodent samples were collected over the past ten years. Laboratory investigations using virus isolation, electron microscopy, molecular biology (PCR) and serological analysis confirmed Orthopoxvirus infections in 77.9% of human, 49.2% of dairy cattle and 17.9% of rodent samples. The characterisation of the Cantagalo/IOC strain reconfirmed that this virus was a vaccinia-like virus. In other regions of the Rio de Janeiro state, vesicular/pustular infections in animals and humans are suspected but these have not yet been confirmed. A continuous surveillance system has been established to monitor these regions in addition to several other states of the Brazilian Federation.
Assuntos
Orthopoxvirus/patogenicidade , Infecções por Poxviridae/epidemiologia , Infecções por Poxviridae/veterinária , Zoonoses/epidemiologia , Animais , Brasil/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/virologia , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/virologia , Humanos , Orthopoxvirus/isolamento & purificação , Doenças dos Roedores/epidemiologia , Doenças dos Roedores/virologia , Virologia/métodos , Zoonoses/virologiaRESUMO
Hantaviruses, family Bunyaviridae, are rodent-borne RNA viruses that have caused cases of hantavirus cardiopulmonary syndrome (HCPS) in various regions of the Americas. There are five hantaviral lineages associated with HCPS in Brazil: Juquitiba virus (JUQV), Araraquara virus (ARAV), Laguna Negra-like virus (LNV), Castelo dos Sonhos virus (CASV), and Anajatuba virus (ANAJV). Three additional hantaviruses have been described in rodents alone: Rio Mearim virus, Jaborá virus, and a hantavirus lineage related to Seoul virus. This study describes the genetic detection and characterization of a Juquitiba-like hantavirus in Oligoryzomys nigripes, or the black-footed pygmy rice rat, in the Serra dos Orgãos National Park, Rio de Janeiro State, where so far no cases of HCPS have been reported.
Assuntos
Reservatórios de Doenças/virologia , Infecções por Hantavirus/veterinária , Orthohantavírus/isolamento & purificação , Sigmodontinae/virologia , Animais , Brasil , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Homologia de SequênciaRESUMO
Determining the reservoir hosts for parasites is crucial for designing control measures, but it is often difficult to identify the role that each host species plays in maintaining the cycle of infection in the wild. One way to identify potential maintenance hosts is to estimate key parameters associated with transmission and pathogenicity. Here we assess the potential for three native rodent species of the Brazilian Pantanal (Clyomys laticeps, Thrichomys pachyurus and Oecomys mamorae) to act as reservoir or maintenance hosts of Trypanosoma evansi, an important parasite of domestic livestock. By analyzing blood parameters of naturally infected wild-caught rodents of these species, we compared their levels of parasitemia and anemia due to T. evansi infection with literature values for other host species infected by this parasite. We also analyzed levels of these blood parameters relative to infection by Trypanosoma cruzi, the causative agent of Chagas disease in humans, for which wild rodents are already thought to be important reservoir species. All three species showed low impacts of the two trypanosomes on their blood parameters compared to other species, suggesting that they experience a low virulence of trypanosome infection under natural conditions in the Pantanal and might act as maintenance hosts of trypanosome infections. The low parasitemia of trypanosome infections suggests that these rodents play a secondary role in the transmission cycle compared to other species, especially compared to the capybara (Hydrochaeris hydrochaeris) which also experiences low pathogenicity due to infection despite much higher levels of parasitemia.
Assuntos
Reservatórios de Doenças/parasitologia , Roedores/parasitologia , Trypanosoma/isolamento & purificação , Tripanossomíase/transmissão , Anemia , Animais , Sangue/parasitologia , Brasil/epidemiologia , ParasitemiaRESUMO
[Prólogo] A concepção da idéia da elaboração deste guia surgiu durante a realização do I Curso de Taxonomia e Sistemática de Roedores Silvestres, realizado no Centro de Pesquisa Aggeu Magalhães, na Fiocruz, em Recife, em 2005, para técnicos de serviços de saúde que atuavam no grupo de vigilância ecoepidemiológica de hantavírus da Secretaria de Vigilância em Saúde (SVS), do Ministério da Saúde (MS). Durante esse curso, ficou evidente a necessidade de um guia para identificação dos roedores brasileiros considerando-se a necessidade de uma identificação inicial pelos técnicos envolvidos nas atividades de pesquisa de campo e no monitoramento e/ou controle de roedores reservatórios em áreas endêmicas de zoonoses.
Assuntos
Roedores , Brasil , Especificidade da EspécieRESUMO
Expansion of human activities frequently results in habitat fragmentation, a phenomenon that has been widely recognized in the last decades as one of the major threats to world's biodiversity. The transformation of a continuous forest into a fragmented area results in a hyper-dynamic landscape with unpredictable consequences to overall ecosystem health. The effect of the fragmentation process on Trypanosoma cruzi infection among small wild mammals was studied in an Atlantic Rain Forest landscape. Comparing continous forest to fragmented habitat, marsupials were less abundant than rodents in the continuous landscape. An overall decrease in small wild mammal richness was observed in the smaller fragments. An anti-T. cruzi seroprevalence of 18% (82/440) was deteced by immunofluorescence assay. Moreover, this seroprevalence was higher in the fragmented habitat than in the continuous forest. According to the collected data, 3 main factors seem to modulate infection by T. cruzi in small wild mammals: (i) habitat fragmentation; (ii) biodiversity loss; (iii) increase of marsupial abundance in mammal communities. Furthermore, an extremely mild controlled infection by T. cruzi was detected since no patent parasitaemia could be detected in fresh blood samples, and no parasites were isolated by haemoculture.
Assuntos
Animais Selvagens/parasitologia , Ecossistema , Mamíferos/parasitologia , Infecções Protozoárias em Animais/epidemiologia , Trypanosoma cruzi/fisiologia , Tripanossomíase/veterinária , Animais , Anticorpos Antiprotozoários/sangue , Biodiversidade , Brasil , Interações Hospedeiro-Parasita , Densidade Demográfica , Infecções Protozoárias em Animais/parasitologia , Infecções Protozoárias em Animais/transmissão , Estudos Soroepidemiológicos , Árvores , Tripanossomíase/epidemiologia , Tripanossomíase/parasitologia , Tripanossomíase/transmissãoRESUMO
This study reports 2 years of the population dynamics and reproduction of a small mammal community using the removal method. The study was conducted in a rural area of the Atlantic Forest, in Sumidouro, Rio de Janeiro State, Brazil. The population sizes, age structure and reproduction were studied for the four most common species in the study area. The overall diversity was 1.67 and ranged between 0.8 to 1.67. The species richness was 13 considering the whole study. The most abundant species were the rodents Nectomys squamipes (n = 133), Akodon cursor (n = 74), Oligoryzomys nigripes (n = 25) and the marsupials Didelphis aurita (n = 58) and Philander frenatus (n = 50). Seven other rodents were captured once: Necromys lasiurus, Akodon montensis, Sooretamys angouya, Oecomys catherine, Oxymycterus judex, Euryzygomatomys spinosus and Trinomys iheringi. There were higher peaks for diversity and species richness during the winter (dry) months, probably due to higher food availability. The marsupials had a seasonal reproduction with highest population sizes at the end of the rainy seasons. Nectomys squamipes reproduced mostly during rainy periods. Akodon cursor reproduced predominantly in the winter with the highest population peaks occurring during this season. The analysis of the population dynamics of the rodent species indicated that no species behaved as an agricultural pest, probably due to the heterogeneous landscape of high rotativity of vegetable cultivation. Rodent populations were more susceptible to the removal procedure than marsupial ones.