RESUMO
We carried out a morphometric study of the esophagus of cross-bred dogs experimentally infected or consecutively reinfected with Trypanosoma cruzi 147 and SC-1 strains, in order to verify denervation and/or neuronal hypertrophy in the intramural plexus. The animals were sacrificed in the chronic stage, 38 months after the initial infection. Neither nests of amastigotes, nor myositis or ganglionitis, were observed in all third inferior portions of esophageal rings analyzed. No nerve cell was identified in the submucous of this organ. There was no significant difference (p>0.05) between the number, maximum diameter, perimeter, or area and volume of the nerve cells of the myenteric plexus of infected and/or reinfected dogs and of the non-infected ones. In view of these results we may conclude that the 147 and SC-1 strains have little neurotropism and do not determine denervation and/or hypertrophy in the intramural esophageal plexuses in the animals studied, independent of the reinfections.
Assuntos
Doença de Chagas/veterinária , Doenças do Cão/patologia , Esôfago/inervação , Plexo Mientérico/patologia , Plexo Submucoso/patologia , Animais , Doença de Chagas/patologia , Cães , Esôfago/patologia , Feminino , Masculino , Recidiva , Trypanosoma cruziRESUMO
The role of reinfection in the evolution of Chagas' disease was evaluated in dogs alternately infected with the 147 and SC-1 strains of Trypanosoma cruzi. A parasitologic, serologic, clinical, and electrocardiographic follow-up was carried out on the infected and noninfected dogs. The dogs were reinfected five times over a period of 38 months. No deaths were observed during the experiment. They presented a brief oligosymptomatic acute phase. The level of parasitemia decreased progressively with the number of reinfections. Bloodstream parasites were not detectable after the fifth reinfection. All parasite samples isolated during the follow-up were zymodeme B, corresponding to strain 147, irrespective of the strain with which the dogs were first infected and of the triatomine species used for isolation. Conversely, amplification by the polymerase chain reaction of a segment of the T. cruzi mini-exon gene showed the simultaneous presence of both strains in three of the eight reinfected animals. Antibody titers were greater among the dogs successively infected than those infected only once. Neither amastigotes nor T. cruzi DNA were detected in the tissues of the infected dogs. Alterations related to Chagas' disease were identified only in the heart and consisted of chronic focal and discrete myocarditis, compatible with the indeterminate form of Chagas' disease. All infected dogs developed this form of the disease, which was independent of the number of infections.
Assuntos
Anticorpos Antiprotozoários/sangue , Doença de Chagas/veterinária , Doenças do Cão/parasitologia , Trypanosoma cruzi/patogenicidade , Animais , Cardiomiopatia Chagásica/parasitologia , Cardiomiopatia Chagásica/veterinária , Doença de Chagas/parasitologia , Primers do DNA , Modelos Animais de Doenças , Doenças do Cão/sangue , Cães , Eletrocardiografia/veterinária , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Masculino , Reação em Cadeia da Polimerase/veterinária , Recidiva , Trypanosoma cruzi/classificação , Trypanosoma cruzi/genética , Trypanosoma cruzi/imunologiaRESUMO
Primary and secondary data show the importance and distribution of human Chagas disease (HCD) in Northeast Brazil. Among the 27 detected vector species, Triatoma infestans, Panstrongylus megistus, Triatoma brasiliensis and Triatoma pseudomaculata are epidemiologically important. Major medical impact is attributed to T. infestans and P. megistus, the most domiciliated and vulnerable species, while the other two are native and more difficult to control. Regional differences in transmission and medical impact of HCD exist in the Northeast, where in general the disease appears to be less harmful than in other Brazilian regions like the Southeast and State of Goiás. There is a downward trend in HCD transmission and morbidity in the Northeast, its control in the region is a cause of concern because of the decommissioning of the National Health Foundation without a corresponding assimilation of its routine activities by regional and municipal institutions.
Assuntos
Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Insetos Vetores , Panstrongylus , Triatoma , Adolescente , Adulto , Animais , Brasil/epidemiologia , Doença de Chagas/mortalidade , Criança , Pré-Escolar , Humanos , Lactente , Recém-Nascido , Pessoa de Meia-Idade , Densidade Demográfica , Prevalência , Características de Residência , População Rural/estatística & dados numéricos , Triatoma/classificação , Trypanosoma cruziRESUMO
Due to the overlapping distribution of Trypanosoma rangeli and T. cruzi in Central and South America, sharing several reservoirs and triatomine vectors, we herein describe a simple method to collect triatomine feces and hemolymph in filter paper for further detection and specific characterization of these two trypanosomes. Experimentally infected triatomines feces and hemolymph were collected in filter paper and specific detection of T. rangeli or T. cruzi DNA by polymerase chain reaction was achieved. This simple DNA collection method allows sample collection in the field and further specific trypanosome detection and characterization in the laboratory.