RESUMO
We assessed the utility of an enzyme-linked immunosorbent assay (ELISA) for the detection of hantavirus-specific antibodies from sera of Oligoryzomys longicaudatus, the principal reservoir of Andes virus (ANDV), using an antigen previously developed for detection of antibodies to Sin Nombre virus (SNV) in sera from Peromyscus maniculatus. The assay uses a protein A/G horseradish peroxidase conjugate and can be performed in as little as 1.5 hours. Serum samples from Oligoryzomys longicaudatus collected in central-south Chile were used and the assay identified several that were antibody positive. This assay can be used for the rapid detection of antibodies to divergent hantaviruses from geographically and phylogenetically distant rodent species.
Assuntos
Anticorpos Antivirais/sangue , Testes Diagnósticos de Rotina/métodos , Infecções por Hantavirus/veterinária , Orthohantavírus/isolamento & purificação , Sigmodontinae/virologia , Medicina Veterinária/métodos , Animais , Antígenos Virais , Chile , Ensaio de Imunoadsorção Enzimática/métodos , Orthohantavírus/imunologia , Infecções por Hantavirus/virologia , Fatores de Tempo , Virologia/métodosRESUMO
In Chile, the main vector of Chagas disease, Triatoma infestans, is under control after insecticide spraying. However, it has been found colonizing wild habitats. This study evaluated Trypanosoma cruzi infection of sylvatic and domiciliary T. infestans and identified their parasite genotypes. The sample studied was composed mainly of T. infestans sylvatic nymphs and domiciliary adults from a semi-urban area with human dwellings under vector control surveillance. Results showed prevalences of 57.7% in nymphs and 68.6% in adults. Hybridization tests showed a major T. cruzi lineage (TcI) circulating in sylvatic (93.3%) and domiciliary (100%) T. infestans. TcII, TcV, and TcVI were also detected, mainly in nymphs, suggesting differential adaptation of T. cruzi lineages among instars. We also discuss the origin of domiciliary individuals of T. infestans and the risk of human infection by triatomines of sylvatic foci that invade houses despite vector control programs.
Assuntos
DNA de Protozoário/isolamento & purificação , Insetos Vetores/parasitologia , Triatoma/parasitologia , Trypanosoma cruzi/patogenicidade , Animais , Doença de Chagas/parasitologia , Doença de Chagas/transmissão , Chile , DNA de Protozoário/genética , Ecossistema , Genótipo , Habitação , Insetos Vetores/efeitos dos fármacos , Inseticidas/farmacologia , Hibridização de Ácido Nucleico/métodos , Ninfa/efeitos dos fármacos , Ninfa/parasitologia , Fatores de Risco , Triatoma/efeitos dos fármacos , Trypanosoma cruzi/genética , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
Chagas disease is one of the most important vector-borne diseases in Latin America. The disease, caused by the flagellate protozoan Trypanosoma cruzi, is commonly transmitted to humans by Triatoma infestans in South America. Using mitochondrial DNA sequences, we assessed alternative biogeographic scenarios of dispersal of T. infestans using coalescence simulations. We also assessed phylogeographic structure and spatial genetics of T. infestans in Chile. Two major routes of dispersal in southern South America were supported including a dual-origin of T. infestans in Chile. Phylogeographic analyses identified two primary clades with Chilean haplotypes partitioned into either a northern cluster with Peruvian and Bolivian haplotypes or a north-central cluster with Argentinean and Uruguayan haplotypes. The north-central clade is further divided into two subgroups. Domestic and sylvatic T. infestans in central Chile were not segregated in the phylogeographic reconstruction. Spatial genetic analyses show higher distances in northern Chile, congruent with the presence of two divergent lineages of T. infestans. Phylogenetic evidence does not unequivocally support the hypothesized Bolivian origin of T. infestans, so we discuss alternative scenarios.
Assuntos
DNA Mitocondrial/genética , Insetos Vetores , Filogenia , Triatoma/parasitologia , Trypanosoma cruzi/isolamento & purificação , Animais , Chile , Análise por Conglomerados , Geografia , Triatoma/classificaçãoRESUMO
In the present study, we compared Trypanosoma cruzi infection in four native mammals from a hyperendemic area of Chagas disease in Chile for two different periods to assess the occurrence of interannual variation (1999-2000 vs. 2005-2006). Parasite detection in mammals is performed by polymerase chain reaction assays and confirmed by Southern blot analysis and hybridization test with a universal probe. Results showed significant differences in the levels of T. cruzi infection between the compared periods. We suggest that the major El Niño event occurred in 1997-1998, a large-scale global climatic fluctuation, could be indirectly explaining the extremely high T. cruzi infection in 1999-2000 by means of a time-lag response of the wild transmission cycle of Chagas disease in semiarid Chile after the irruption of small rodent populations.
Assuntos
Doença de Chagas/veterinária , Mamíferos/parasitologia , Animais , Doença de Chagas/epidemiologia , Chile , Gambás/parasitologia , Doenças dos Roedores/epidemiologia , Doenças dos Roedores/parasitologia , Roedores/parasitologia , Fatores de Tempo , Trypanosoma cruziRESUMO
Trypanosoma cruzi, the etiologic agent of Chagas disease, presents a complex life cycle, cycling between reduviid vectors and wild and domestic mammals. The European rabbit is an introduced species in America, but its role as reservoir in the wild transmission cycle of Chagas disease remains unknown. We used polymerase chain reaction, Southern blot, and hybridization tests to detect infection and characterize genotypes in rabbits from a hyperendemic area of Chagas disease in Chile. Results show 38% of infection with different genotypes. We provide evidence that rabbits are naturally infected with T. cruzi, which may have important epidemiologic consequences for the wild transmission cycle.
Assuntos
Doença de Chagas/veterinária , Reservatórios de Doenças/parasitologia , Coelhos/parasitologia , Trypanosoma cruzi/genética , Animais , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Chile/epidemiologia , Genótipo , Trypanosoma cruzi/classificaçãoRESUMO
The Southern Pacific Ocean coast has been traditionally considered a non-active transmission area for Chagas disease. In this report, we show evidence of Trypanosoma cruzi infection in the sylvatic kissing bug Mepraia gajardoi from the northern Chilean coast.
Assuntos
Doença de Chagas/transmissão , Insetos Vetores/parasitologia , Reduviidae/parasitologia , Trypanosoma cruzi/isolamento & purificação , Animais , Chile , DNA de Protozoário/análise , DNA de Protozoário/isolamento & purificação , Interações Hospedeiro-Parasita , Oceano Pacífico , Reação em Cadeia da Polimerase , Trypanosoma cruzi/classificação , Trypanosoma cruzi/genéticaRESUMO
The aim of this study was to compare the feeding and defecation behavior of wild and laboratory-reared specimens of Mepraia spinolai confronted to the rabbit, Oryctolagus cuniculus, and the wild rodent, Octodon degus as hosts. Time variations in bite, blood ingestion and defecation were analized, including weight gain after a blood meal. Considering bite duration significant differences were found according to the origin of insect. Laboratory reared specimens spent less biting time when fed on rabbit. No differences were found in blood ingestion time nor in defecation time. Blood meal was significantly different according to origin of the insect. Wild specimens of M. spinolaifed more blood than the laboratory ones. From these results it was apparent that there are not significant differences in the bug behavior when they are confronted to these hosts, being both mammals of a similar epidemiological importance.
Se estudió la conducta de alimentación y defecación de ejemplares de Mepraia spinolai provenientes de laboratorio y terreno alimentados sobre conejo, Oryctolagus cuniculus, y sobre roedores degu, Octodon degus. Se analizaron las diferencias en el tiempo de picada (latencia de picada), tiempo de ingesta de sangre, tiempo de defecación y cantidad de sangre ingerida en condiciones de laboratorio. El análisis del tiempo de picada, mostró que hubo diferencias significativas según origen de las vinchucas; esto es que los ejemplares de laboratorio demoraron el menor tiempo en picar a los conejos de terreno con el mismo hospedero, quienes tomaron el mayor tiempo. No hubo diferencias significativas para el tiempo de ingesta de sangre ni para el tiempo de defecación. Se encontraron diferencias entre grupos al comparar la cantidad de sangre ingerida; los insectos provenientes del terreno consumieron la mayor proporción de sangre comparados con los criados en laboratorio. De acuerdo con los resultados, estos insectos son generalistas en cuanto a hospederos y por tanto ninguno de ellos demostró tener una mayor importancia en el rol epidemiológico de mantención del parásito en el ciclo silvestre de la enfermedad.
Assuntos
Animais , Comportamento Alimentar/fisiologia , Defecação/fisiologia , Reduviidae/fisiologia , Chile , Ecossistema , Doença de Chagas/transmissão , Mordeduras e Picadas de Insetos , Insetos Vetores/fisiologia , Interações Hospedeiro-Parasita , Fatores de TempoRESUMO
Trypanosoma cruzi is the causative agent of Chagas disease, a zoonosis involving domestic and sylvatic mammalian reservoirs. Since scarce information has been published about the susceptibility of T. cruzi lineages to other triatomine species besides Triatoma infestans, we evaluate the susceptibility of T. infestans and Mepraia spinolai to different T. cruzi lineages, originated from naturally infected Octodon degus rodents as mammal host. Xenodiagnosis-PCR methods to detect T. cruzi positive rodents and genotyping to differentiate T. cruzi lineages (TcI, TcIIb, TcIId and TcIIe) identified singly and mixed T. cruzi infections. More infections and nearly all mixed infections were identified using the wild vector M. spinolai than T. infestans.