ABSTRACT
Objective: To isolate and identify the exact species of the genus Mycobacterium from Didelphis (D.) virginiana, and the direct implications of this bacterium to public health and veterinary medicine. Methods: Thirty-one D. virginiana were captured and necropsied in Hidalgo, Mexico. Tissue samples were collected to culture mycobacteria present and examine individual specimens' histopathology. Mycobacterium identification was obtained through the application of amplification and sequencing of 16S rDNA techniques. Results: Three strains were isolated and identified as Mycobacterium (M.) avium subsp. hominissuis by utilizing M. avium complex- specific primers. Granulomatous lesions were observed in the subpleural zone (granuloma grade Π ) and bronchial (granuloma grade I ) of the lungs of D. virginiana with positive isolation. Conclusions: Three strains of M. avium subsp. hominissuis, from lung tissue samples of D. virginiana were identified. This subspecies of M. avium has important implications in public health and veterinary medicine.
ABSTRACT
Objective: To isolate and identify the exact species of the genus Mycobacterium from Didelphis (D.) virginiana, and the direct implications of this bacterium to public health and veterinary medicine. Methods: Thirty-one D. virginiana were captured and necropsied in Hidalgo, Mexico. Tissue samples were collected to culture mycobacteria present and examine individual specimens' histopathology. Mycobacterium identification was obtained through the application of amplification and sequencing of 16S rDNA techniques. Results: Three strains were isolated and identified as Mycobacterium (M.) avium subsp. hominissuis by utilizing M. avium complex- specific primers. Granulomatous lesions were observed in the subpleural zone (granuloma grade Π ) and bronchial (granuloma grade I ) of the lungs of D. virginiana with positive isolation. Conclusions: Three strains of M. avium subsp. hominissuis, from lung tissue samples of D. virginiana were identified. This subspecies of M. avium has important implications in public health and veterinary medicine.
ABSTRACT
Endogenous lipid pneumonia was found in 11 out of 15 (73.3%) opossums (Didelphis virginiana) captured in six municipalities from the state of Colima, Mexico. Macroscopically, multifocal yellow white subpleural plaques were found in the dorsocaudal region of both lungs. These lesions were extended to the pulmonary parenchyma. Microscopically, they were characterized by aggregates of macrophages in the alveolar walls and spaces. These macrophages had small lipid vacuoles in the cytoplasm. Also, hyperplasia of pneumocytes type II, perivascular lymphoid hyperplasia, emphysema and fibrosis were discovered. Based on these findings, endogenous lipid pneumonia was diagnosed, which seemed to be associated in 11 (73.3%) opossums with the presence of Didelphostrongylus hayesi in lungs.
Se encontró neumonía lipídica endógena en 11 (73.3%) de 15 tlacuaches (Didelphis virginiana) capturados en seis municipios del estado de Colima, México. Macroscópicamente se observaron placas subpleurales multifocales (1-5 mm) de color amarillo pálido en la región dorso caudal de ambos pulmones. Estas lesiones se extendían al parénquima pulmonar. Microscópicamente se caracterizaban por agregados de macrófagos en los espacios y paredes alveolares. Los macrófagos tenían abundantes vacuolas pequeñas lipídicas en el citoplasma. También se observó hiperplasia de neumocitos tipo II, hiperplasia linfoide perivascular, enfisema y fibrosis. Con base en estos hallazgos se diagnosticó neumonía lipídica endógena, la cual parecía estar asociada en 11 de los tlacuaches, con la presencia de Didelphostrongylus hayesi en los pulmones.
ABSTRACT
Paragonimiasis is a zoonotic disease in Mexico caused by adult digeneans of Paragonimus mexicanus species. Life cycle of this parasite involves two necessary intermediate hosts: a snail and a crab, and a mammal serving as the definitive host. Humans acquire the infection when eating raw or undercooked crabs infected by metacercariae. In March 2005, six opossums (Didelphis virginiana) were captured in Colima, Mexico. These opossums were euthanized in order to identify lesions caused by lung paragonimiasis. Infected lungs were processed and stained following the standard histological techniques. Four of the six opossums (67%) carried 25 adult parasites identified as P. mexicanus. The lung with the greatest number of parasites showed 13 multifocally distributed granulomas. The main histological changes were: infiltration of monocytes, lymphocytes, macrophages, plasma cells, epithelioid and giant cells, abundant neutrophils and eosinophils, as well as central necrosis of the eosinophilic granuloma. Likewise, interstitial pneumonia was observed due to the presence of eggs between the granuloma walls and alveolar spaces. This study represents the first description of the pulmonary lesions caused by P. mexicanus in wild mammals.
La paragonimiasis constituye una enfermedad zoonótica con origen en México por el digeneo adulto Paragonimus mexicanus. El ciclo de vida de esta especie involucra dos hospederos intermediarios obligatorios: un caracol y un cangrejo, así como un mamífero que actúa como hospedero definitivo. La infección humana ocurre a través de la ingestión de carne de cangrejo cruda o insuficientemente cocida, parasitada por metacercarias. En marzo de 2005, seis tlacuaches (Didelphis virginiana) fueron capturados en Colima, México; fueron sacrificados con el fin de extraer los pulmones mediante necropsia para identificar las lesiones ocasionadas por el parásito. Los pulmones parasitados fueron procesados y teñidos de acuerdo con las técnicas histológicas convencionales. Cuatro de los seis (67%) hospederos resultaron infectados por 25 gusanos adultos identificados como P. mexicanus. En un pulmón se encontraron hasta 13 granulomas, distribuidos multifocalmente. Los principales cambios histológicos fueron: infiltración inflamatoria de monocitos, linfocitos, macrófagos, células plasmáticas, epitelioides y gigantes, con abundantes neutrófilos y eosinófilos, así como necrosis central del granuloma eosinofílico. Asimismo, se observó neumonía intersticial debido a la presencia de huevos entre las paredes del granuloma y los espacios alveolares. Este estudio representa la primera descripción de lesiones pulmonares ocasionadas por P. mexicanus en mamíferos silvestres.