Gastrointestinal helminths of waterfowl (Anatidae: Anatinae) in the Lerma marshes of central Mexico: Some pathological aspects.

Gastrointestinal helminths of migratory waterfowl can cause several lesions that may affect the health and even the survival of their hosts. As part of an ongoing project that aims to inventory the helminth species that infect this group of birds, as well as the histopathologic lesion they cause, a total of 200 digestive tracts of nine species of anatid birds (Spatula discors, S. cyanoptera, S. clypeata, Mareca strepera, M. americana, Anas crecca, A. acuta, A. platyrhynchos diazi, and Oxyura jamaicensis) were collected in the Atarasquillo marsh of Lerma, in the State of Mexico. The present work had a twofold goal: to determine the taxonomic identity of the helminth species present in waterfowl as well as their infection levels and to describe the lesions caused by gastrointestinal parasites in migratory and resident anatids in Atarasquillo marsh, State of Mexico. The specimens were examined using routine helminthological and histopathological techniques. A total of 23 helminths were identified: six trematodes (Zygocotyle lunata, Notocotylus triserialis, Notocotylus seineti, Psilochasmus oxyurus, Australapatemon burti and Cotylurus magniacetabulus), four cestodes (Cloacotaenia megalops, Fimbriaria fasciolaris, Gatrotaenia cygni and Diorchis sp.), eleven nematodes (Echinuria uncinata, Tetrameres sp., Tetrameres fissispina, Hystrichis sp., Streptocara sp., Amidostomum sp., Epomidiostomum uncinatum, Capillaria sp., Capillaria contorta, Ascaridia sp. and Heterakis sp.) and two acanthocephalans (Pseudocorynosoma constrictum and Filicollis sp.). At the proventriculus level, Echinuria uncinata caused the most severe lesions; in the gizzard, Amidostomum sp. and E. uncinatum produced hemorrhages and necrosis. Finally, the main lesions found in the intestine (necrosis, heterophilic granulomas and the formation of lumps on the serosa) were caused by the implantation of the acanthocephalans' proboscis. Eleven species of gastrointestinal helminths found are new records for the Lerma marshes, as well as the first record in Mexico of the nematode Capillaria contorta and the acanthocephalan Filicollis sp.

Fat, Cartilage, and Bone Metaplasia in Lungs of Cattle With Caudal Pleural Lesions and Subjacent Interstitial Fibrosis.

The changes associated with condemned lungs in cattle with chronic pleural lesions of the caudal lobes were characterized by histology and immunohistochemistry (IHC). Fibroproliferative pleural lesions were microscopically confirmed. Occasionally, the pleural lesions also included adipose, chondroid, and osseous metaplasia that were covered by mesothelial cells, mostly in the absence of inflammation. Other lungs also showed fibrosis in the subpleural interstitium and interlobular septa. In both condemned and noncondemned lungs, immunoreactivity to Wilms tumor 1 (WT1) was normally observed on surface mesothelial cells but not on the submesothelial fibroblasts and myofibroblasts. Conversely, the myofibroblasts beneath the pleura, but not the mesothelial cells, showed immunoreactivity to alpha smooth muscle actin and calponin. However, in the lungs with myofibroblastic foci in the pleura, the proliferated cells maintained WT1 immunoreactivity similar to those of some metaplastic cells. These findings may reflect the plasticity of mesothelial cells in vivo.

Effect of Metarhizium anisopliae (Ascomycete), Cypermethrin, and D-Limonene, Alone and Combined, on Larval Mortality of Rhipicephalus sanguineus (Acari: Ixodidae).

The effect of the fungus Metarhizium anisopliae Ma14 strain, D-limonene, and cypermethrin, alone and combined, on the mortality of Rhipicephalus sanguineus Latreille larvae was evaluated. Eight separate groups with 25 tick larvae were inoculated with the fungus, cypermethrin, and D-limonene, and four groups were used as untreated controls. The groups were inoculated with serial dilutions of each treatment material: for example, conidial concentrations were 1 × 101, 1 × 102, 1 × 103, 1 × 104, 1 × 105, 1 × 106, 1 × 107, and 1 × 108. A complete randomized experimental design was used. Significant differences were obtained between fungal concentrations, with larval mortalities ranging from 29 to 100%; the D-limonene concentrations showed significant differences, with mortalities that ranged from 47.9 to 82.6%, and cypermethrin mortalities ranged from 69.9 to 89.9% when each was applied alone. In the combined application, the serial dilution of the Ma14 fungus plus cypermethrin at 0.1% concentration caused mortalities ranging from 92.9 to 100%; the mix of serially diluted Ma14 plus D-limonene at 0.1% caused mortalities from 10.3 to 100%; and the mix consisting of serially diluted D-limonene plus cypermethrin at 0.1% caused mortalities from 7.4 to 35.9%. Further laboratory and field research could show that these materials, alone and in combinations, are useful in future tick management and control programs.

Bovine diseases causing neurological signs and death in Mexican feedlots.

The number of large feedlot operations, similar to that of USA and Canada, has notably increased in Mexico in the last three decades. Clinical and laboratory diagnoses of neurological diseases in feedlot cattle are crucial in Mexico and Central America because of the high incidence of bovine paralytic rabies (BPR). Because of its zoonotic potential, BPR must be promptly diagnosed and differentiated from other bovine neurological diseases such as thrombotic meningoencephalitis (TME), polioencephalomalacia (PEM) and botulism. More recently, BPR and botulism have been diagnosed with increasing frequency in Mexican feedlots. Neither BPR nor botulism has relevant gross lesions, thus post-mortem diagnosis without laboratory support is impossible. Herein, we describe five outbreaks of neurological diseases in Mexican feedlots in which BPR, botulism and PEM were diagnosed either independently or in combination. A diagram illustrating the most conspicuous pathologic findings and ancillary laboratory test required to confirm the diagnoses of these neurological diseases in feedlot cattle is proposed.

Neumonía lipídica endógena en tlacuaches (Didelphis virginiana) capturados en el estado de Colima, México / Endogenous lipid pneumonia in opossum (Didelphis virginiana) captured in the state of Colima, Mexico

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.

Detection of antibodies and risk factors for infection with bovine respiratory syncytial virus and parainfluenza virus 3 in dual-purpose farms in Colima, Mexico.

A cross-sectional study was carried out, from November 2007 to March 2008, to estimate the prevalence of and to determine risk factors associated with bovine syncytial respiratory virus (BRSV) and parainfluenza 3 virus (PIV3) in dual-purpose herds in Colima, México. One hundred and seventy-six sera from 33 herds for PIV3 and 232 sera from 44 herds for BRSV were used. Sera were analyzed by indirect ELISA for the detection of antibodies against BRSV and PIV3 in cattle herds to determine the seroprevalence of respiratory diseases. The apparent and true prevalences for PIV3 were 60.8% and 54.4% and for BRSV 52.2% and 50.8%, respectively. The percentage of herds showing at least one positive animal was 78.7% for PIV3, and 93.2% for BRSV. Age (≤ 12, 13-48, and >48 months old) and respiratory signs (no, yes) showed significant association (P < 0.05) with PIV3 and age with BRSV. This study showed that animals were exposed to both viruses and that age was the main risk factor. The need to establish new vaccination plans to effectively protect cattle against those infections in the state of Colima, Mexico is suggested.

Lesiones pulmonares en tlacuaches (Didelphis virginiana) infectados naturalmente por Paragonimus mexicanus en Colima, México / Lung lesions in opossums (Didelphis virginiana) naturally infected by Paragonimus mexicanus in Colima, Mexico

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.

¿Envenenamiento por consumo de Asclepias curassavica o nematodiasis gastrointestinal en ovinos en pastoreo? Hallazgos de un estudio de caso / Grazing sheep poisoned by milkweed Asclepias curassavica or gastrointestinal nematosis? A case report findings

A case study was conducted with the objective to describe and determine whether the occurrence of sheep poisoning was due to milkweed Asclepias curassavica or an acute case of gastrointestinal nematosis. Milkweed population and distribution as well as animal data such as grazing behavior and poisoning symptoms were collected in the field. A necropsy was carried out with the objective to describe histopathological findings in relation to the observed symptomatology and confirm poisoning diagnosis. Symptoms such as inability to stand, muscle paralysis, salivation, diarrhea, followed by facial edema and death, began when the animals grazed on native grass prairie with a scarcity of forage but a high density of A. curassavica. Nevertheless, the study of the grazing behavior in the area where there were intoxication cases showed only exploratory contacts between lambs and milkweed. Necropsy findings showed diffuse edema of the subcutaneous tissue (anasarca), serous fat atrophy, poor development of pale muscles, hydrothorax, hydropericardium, hydroperitoneum and abomasum containing blood, mucous, and abundant blood-sucking nematodes Haemonchus contortus with no evidence of poisoning. These findings indicated a severe mucohemorrhagic abomasum inflammation and generalized edema associated with a hypoproteinemia due to an acute haemonchosis as the cause of death.

Se realizó un estudio de caso con el objetivo de documentar la posible ocurrencia de envenenamiento por el consumo de Asclepias curassavica o de casos agudos de nematodiasis gastrointestinal en ovinos en pastoreo. Se registró la densidad de población, la ubicación espacial de la maleza y el tipo de vegetación; además, se observaron los hábitos de pastoreo del rebaño y la semiología mostrada por los ovinos afectados. Posteriormente se realizó una necropsia con la finalidad de describir hallazgos histopatológicos relacionados con la semiología observada, que confirmaran el diagnóstico de envenenamiento. El estudio de campo mostró que la aparición de signos característicos de envenenamiento, como incoordinación, parálisis muscular, salivación, diarrea, seguidos por edema facial y muerte, inició cuando los animales pastaban bajo condiciones propicias para la ingestión de la planta tóxica: mala oferta de forraje y abundante población de A. curassavica. El estudio de los hábitos de pastoreo en el área en que se presentaron los casos de intoxicación, sólo mostró acercamientos y consumos de A. curassavica de tipo exploratorio, mientras que la necropsia mostró un edema generalizado del tejido subcutáneo (anasarca) con atrofia serosa de la grasa y músculos pálidos con mal desarrollo, hidrotórax, hidropericardio, hidroperitoneo y abomaso con presencia abundante de sangre, moco y nematodos del género Haemonchus contortus sin evidencias de intoxicación. Se concluye que la muerte de los animales se debió a abomasitis mucohemorrágica severa difusa y edemas generalizados asociados con una hipoproteinemia causados por hemoncosis aguda.

Patología de las tortugas marinas (Lepidochelys olivacea) que arribaron a las playas de Cuyutlán, Colima, México / Pathology in the Olive Ridley turtles (Lepidochelys olivacea) that arrived to the shores of Cuyutlan, Colima, Mexico

The purpose of this work was to report the causes of mortality of eleven Olive Ridley Turtle (Lepidochelys olivacea) that arrived to the shore of Cuyutlan, Colima, Mexico, in a critical health condition between the months of June and September of 2006. The signs presented were: inability to swim, weakness, loss of weight, sunken eyes, lethargy and mesh lesions in fins and shell. The necropsy was carried out. Representative lesion samples were collected from the main organs and they were fixed in 10% buffered formalin pH 7.2 using the histological technique and the hematoxylin-eosine tint. The results were: six cases (60%) presented multifocal hepatic haemochromatosis, three (30%) presented multifocal non supurative myocarditis, two (20%), multifocal granulomatous nephritis associated with Paecilomyces sp with calcification. Intestinal lymphangiectasia and heterophilic diffuse perihepatitis. Other pathologies included: one case (10%) presented cutaneous fibropapil lomas, bacterial necrotic ulcerative dermatitis; one more presented multifocal granulomatous pneumonia associated with Paecilomyces sp; in three cases, intestinal trematode (Adenogaster serialis); in fi ve epibiontes (Chelonibia testudinaria) in fins; and in one, a blood parasite (Toddia sp). The findings of these diseases will permit to propose preventive medicine with the aim to preserve marine turtles in Mexico..

El objetivo del trabajo fue informar las causas de mortalidad de once tortugas marinas Golfinas (Lepidochelys olivacea), que arribaron moribundas entre junio y septiembre de 2006 a las playas de Cuyutlán, Colima, México. Los signos que presentaron fueron: inhabilidad para nadar, debilidad, pérdida de peso, ojos hundidos, letargia, lesiones en aletas y caparazón por enmallamiento. Después de que las tortugas murieron, se procedió a realizar la necropsia. Se tomaron muestras representativas de las lesiones de los principales órganos y se colocaron en formalina amortiguada al 10% pH 7.2 para su fijación. Las muestras fueron procesadas por la técnica histológica de rutina y se tiñeron con hematoxilina-eosina. Los resultados fueron: en seis casos (60%) se presentó hemocromatosis multifocal hepática; en tres (30%), miocarditis multifocal no supurativa; en dos (20%), nefritis multifocal granulomatosa asociada con Paecilomyces sp, con calcificación, linfangiectasia intestinal y perihepatitis difusa heterofílica. Otras patologías incluyeron en un caso fibropapiloma cutáneo (10%); en otro dermatitis ulcerativa necrótica bacteriana; en uno más, neumonía multifocal granulomatosa, asociada con Paecilomyces sp; en tres, trematodos intestinales Adenogaster serialis; en cinco, epibiontes (Chelonibia testudinaria) en aletas; y en uno, hemoparásito intraeritrocítico (Toddia sp). El conocimiento de estas enfermedades permitirá proponer medidas curativas o de medicina preventiva con el fin de conservar las tortugas marinas en México.

Prevalence of Toxoplasma gondii antibodies and the relation to risk factors in cats of Colima, Mexico.

The prevalence of Toxoplasma gondii antibodies in 80 domestic cats was studied in the city of Colima, Mexico, using an indirect IgG-ELISA. Antibodies were found in 28.8% of the cats, with significantly higher (P = 0.029) prevalence in southern and central zones (33.8%) than the northern zone (6.6%). Prevalence among cats fed with homemade food was higher than those eating commercial pellets (40.6% [vs.] 20.8%; P = 0.055). Overall, the prevalence of T. gondii antibodies in the cats of Colima was lower than in many other countries.

Reacción inflamatoria causada por larvas de gnathostoma sp (nematoda: gnathostomatidae) en músculos de aves ictiófagas en México / Inflammatory reaction caused by larvae of Gnathostoma sp (nematoda: Gnathostomatidae) in muscles of fish-eating birds in Mexico

El propósito del presente estudio fue determinar las especies de aves, principalmente ictiófagas, que fungen como dispersoras de Gnathostoma sp y describir las lesiones causadas por larvas de nemátodos pertenecientes a este género en los paquetes musculares donde son albergadas. Veinticinco aves pertenecientes a cuatro familias en seis localidades fueron estudiadas, de ellas se recolectaron 15 larvas del tercer estadio avanzado (L3A) de seis aves ictiófagas por medio de digestión artificial de tejido muscular; secciones de músculo esquelético infectados con larvas se fijaron en formalina al 10 por ciento para estudios histológicos. Las evidencias señalan que las larvas contenidas en los músculos de las aves causan una reacción inflamatoria de tipo granulomatosa.