Isolation and Histopathological Changes Associated with Non-Tuberculous Mycobacteria in Lymph Nodes Condemned at a Bovine Slaughterhouse.

Background: non-tuberculous mycobacteria (NTM) infect humans and animals and have a critical confounding effect on the diagnosis of bovine tuberculosis. The Official Mexican Standard (Norma Oficial Mexicana, NOM-ZOO-031-1995) for food safety regulates Mycobacterium bovis in cattle, but not the NTM species. The study's objective was to isolate and identify the NTM present in condemned bovine lymph nodes in a slaughterhouse, characterize the histological lesions, and correlate bacteriological and microscopic findings with the antemortem tuberculin skin test. Methods: from 528 cattle, one or two pooled samples of lymph nodes from each animal were cultured for Mycobacteria spp. and processed for histopathology. Results: mycobacteria were isolated from 54/528 (10.2%) of the condemned lymph nodes; 25/54 (46.2%) of these isolates were NTM; 4 bacteriological cultures with fungal contamination were discarded. Granulomatous and pyogranulomatous inflammation were present in 6/21 (28.6%) and 7/21 (33.3%) of the NTM-positive lymph nodes, respectively. The species of NTM associated with granulomatous lymphadenitis were M. scrofulaceum, M. triviale, M. terrae, and M. szulgai, while those causing pyogranulomatous lesions were M. szulgai, M. kansasii, M. phlei, and M. scrofulaceum. Conclusions: the NTM infections can cause false-positive results in the tuberculin test because of cross immune reactivity and interference with the postmortem identification of M. bovis in cattle.

PULMONARY LESIONS CAUSED BY THE LUNGWORM (DIDELPHOSTRONGYLUS HAYESI) IN THE OPOSSUM (DIDELPHIS VIRGINIANA) IN COLIMA, MEXICO.

Didelphostrongylus hayesi is an important and prevalent pulmonary nematode in the opossum ( Didelphis virginiana ). An in-depth description of the pulmonary lesions caused by this nematode is lacking. The objective of this investigation was to make a detailed account of the gross, subgross, and microscopic changes that occur in the lungs of opossums naturally infected with D. hayesi. Forty-four opossums trapped in the state of Colima, Mexico, were euthanized by an overdose of barbiturates. Following a postmortem examination, the right lung was cut from the main bronchi and placed in a Petri dish containing a saline solution for the detection and identification of live parasites. The left lung was fixed and cut serially for subgross microscopic examination and sections of lung were cut and stained for histopathologic examination. The most remarkable gross change in parasitized lungs was a poorly collapsible pulmonary parenchyma and mild emphysema. The right lung tested positive for lungworms on gross examination in 20/44, and 11/44 (25%) of the left lungs showed tan nodules on the pleural surface. Microscopically, the bronchi of 20/44 animals harbored adult and larval stages of D. hayesi (left lung), the same 20 opossums from which nematodes were grossly evident at necropsy (right lung). Adults and larvae were present in bronchi, bronchioles, and alveoli mixed with desquamated cells and many eosinophils, and to a lesser extent neutrophils, alveolar macrophages, and giant cells. Bronchi and bronchioles exhibited goblet cell hyperplasia and metaplasia respectively, and infiltration of lymphoplasmacytic cells in the interstitium and lamina propria. The tan nodules consisted of focal alveolar endogenous lipidosis, which likely resulted from parasitic airway obstruction. The lungs of 3/20 parasitized opossums also showed alveolar bronchiolization (Lambertosis). The absence of Eucoleus aerophilus or bacterial pneumonia incriminates D. hayesi as the putative cause of pulmonary lesions in these opossums.

Coccidioidomycosis in Biopsies with Presumptive Diagnosis of Malignancy in Dogs: Report of Three Cases and Comparative Discussion of Published Reports.

Coccidioidomycosis is a respiratory fungal infection with occasional systemic dissemination. The disseminated coccidioidomycosis is considered a multifaceted disease. In medicine, disseminated coccidioidomycosis is included within a group of infectious diseases that have been referred as the great imitators. In many cases, malignancies are included in the presumptive diagnosis. In veterinary medicine, disseminated coccidioidomycosis is common in dogs. Nonetheless, despite of being a diagnostic dilemma, disseminated coccidioidomycosis is underestimated and frequently not included into differentials, even in endemic zones. Herein, we describe three cases of granulomatous inflammation caused by Coccidioides spp. which were masquerading malignancies in dogs (0.39 %). The presumptive diagnoses in these cases were osteosarcoma, lymphoma and neurofibroma, respectively. A PCR assay employing tissues in paraffin blocks resulted positive for C. posadasii in one of these cases. A comparative discussion on the ambiguous clinic-pathological presentation of disseminated coccidioidomycosis in dogs and humans is included.

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.

Presencia del virus de la diarrea viral bovina y su asociación con otros cuadros patológicos en ganado en corral de engorda / Presence of bovine virus diarrhea in association with other pathologies in feedlot cattle

Bovine feedlots are intensive production systems of significant importance in Mexico. The present study describes the presence of bovine virus diarrhea (BVD) causing subacute to chronic lesions in feedlot cattle, associated with other pathologies. Animals included in this study were discarded after they received therapy several times due to chronic pneumonia, or anaplamosis. Bovine virus diarrhea antigen was identified by immunohistochemistry in small intestine and myocardium in six cases of chronic suppurative bronchopneumonia with extensive areas of casseous necrotic bronchiectasis, previously diagnosed as Mycoplasma bovis pneumonias (retrospective group, n = 6). Furthermore, based on characteristic histopathologic lesions other nine cases were included (prospective group, n = 9). Bovine virus diarrhea antigen was recognized in two animals with pneumonic lesions, including a case with fibrinous bronchopneumonia as well as suggestive lesions of infectious bovine rinotracheitis (1/9), and another one with suppurative bronchopneumonia and myocarditis suggestive of Histophilus somni (1/9). In addition, one positive case was associated to anaplasmosis (1/9). Other two positive cases showed a conspicuous fibrinous peritonitis (2/9). The rest of the animals in this group resulted negative (4/9). Histopathological characteristics of the lesions and their association with the antigen in situ confirm the presence of BVD. This presentation is compatible with the acute infection syndrome. This is the first report of BVD infection and concomitant pathologies in feedlot cattle in Mexico.

El ganado en corral de engorda es un sistema de producción intensivo de gran importancia en México. En este trabajo se describe la infección por diarrea viral bovina (DVB), ocasionado por lesiones subagudas y crónicas en bovinos en corral de engorda, y su asociación con otras patologías. Los animales de este estudio fueron considerados de rechazo después de ser tratados en diferentes ocasiones por enfermedad respiratoria, o bien anaplasmosis. El antígeno de DVB fue identificado por inmunohistoquímica (IHQ) en intestino delgado y miocardio en seis casos de bronconeumonía supurativa crónica con extensas áreas de bronquiectasia con necrosis caseosa, los cuales habían sido previamente diagnosticados como neumonías por Mycoplasma bovis (grupo retrospectivo, n = 6). Además, se incluyeron otros nueve casos con base en las características histopatológicas de las lesiones (grupo prospectivo, n = 9). El antígeno de DVB se reconoció en dos animales con lesiones neumónicas, uno de ellos con bronconeumonía fibrinosa, incluyendo además lesiones probables de rinotraqueítis infecciosa bovina (1/9), y el otro con bronconeumonía supurativa y también miocarditis probable por Histophilus somni (1/9). Adicionalmente, un caso positivo estuvo asociado a anaplasmosis (1/9). Otros dos casos positivos presentaron una distintiva peritonitis fibrinosa (2/9). El resto de los animales de este grupo resultaron negativos a DVB (4/9). Las características histopatológicas de las lesiones y su asociación con el antígeno in situ, confirman la presencia de DVB. Esta presentación es compatible con el síndrome denominado infección aguda. Este es el primer informe de infección por DVB y otras patologías concomitantes en ganado de engorda en México.

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.

Demostración inmunohistoquímica de Mycoplasma bovis en lesiones neumónicas crónicas en ganado en corral de engorda / Immunohistochemical demonstration of Mycoplasma bovis in chronic lung lesions in feedlot cattle

Bovine feedlots are intensive production systems of significant importance in México, United States of America and Canadá. Respiratory diseases are the single most important cause of morbidity and mortality in feedlot cattle. Herein, the gross and microscopic findings in the lungs of cattle with unusually persistent pneumonia unresponsive to aggressive antibiotic treatment in feedlots localized in General Escobedo, Nuevo Leon; Morelia, Michoacan; Mexicali, Baja California, and Culiacan, Sinaloa, Mexico are described. Eight chronic suppurative bronchopneumonia cases with multifocal areas of casseous necrosis were selected. Microscopically, these lesions were bronchocentric and characterized by foci of necrosis surrounded by a pyogranulomatous reaction. Immunohistochemical studies revealed positive reaction to Mycoplasma bovis in all cases. Gross and microscopic lesions associated with M. bovis pneumonia have a conspicuous pattern. This is the first report of M. bovis causing pneumonia in feedlot cattle in Mexico.

El corral de engorda es un sistema de producción intensivo de gran importancia en la ganadería de carne en México, Canadá y Estados Unidos de América. Estudios epidemiológicos indican que las enfermedades respiratorias de los bovinos son el principal problema en corrales de engorda. En este trabajo se describen las lesiones macroscópicas y microscópicas en pulmones de ganado de carne con severa neumonía crónica, a pesar de haber recibido tratamiento con antibióticos en más de tres ocasiones. Se realizaron estudios post mortem de ganado en corrales de engorda localizados en General Escobedo, Nuevo León; Morelia, Michoacán; Mexicali, Baja California y Culiacán, Sinaloa, todos en México. Se seleccionaron ocho casos crónicos de bronconeumonía supurativa con múltiples focos nodulares de exudado necrótico-caseoso. Estos focos necróticos estaban microscópicamente centrados en bronquios y bronquiolos y sus bordes estaban claramente limitados por una reacción piogranulomatosa. Los estudios de inmunohistoquímica demostraron positividad a Mycoplasma bovis en todos los casos. Las lesiones neumónicas macro y microscópicas asociadas con M. bovis tienen un patrón conspicuo. Este es el primer informe de M. bovis en neumonías en ganado de corral de engorda en México.

Use of oxytocin in penned sows and its effect on fetal intra-partum asphyxia.

The objective of the present study was to evaluate in penned sows the effect of two commercial oxytocin products on umbilical cord pathology, degree of asphyxia and intra-partum mortality. This study included 120 sows divided in three groups of 40 animals with eight animals for parities one to five per subgroup, respectively. Group 1 (G(1)) or control received saline solution while oxytocin groups (G(2)) and (G(3)) were injected at the onset of fetal expulsion with two oxytocin products. The doses of oxytocin were as follow: Primiparous sows weighing less than 130 kg received 20 IU; multiparous sows weighing 130-180 g received 30 IU, and those above 250 kg, 40 IU. Piglets born alive and/or dead were classified at birth using a subjective scale based on the degree of meconium staining on skin. Umbilical cords of intra-partum stillbirths (IPS) were classified as adhered or ruptured and subdivided into four categories: without pathological changes, edematous, congested and hemorrhagic. Result analyses revealed significant differences (P < 0.01) between groups 1 and 2, and 1 and 3 regarding the following traits: expulsion interval (min) (X: G(1) 27.7; G(2) 22.6; G(3) 22.2), IPS with a severe stain degree (X: G(1) 0.10; G(2) 0.45; G(3) 0.50), IPS with ruptured umbilical cords (X: G(1) 0.07; G(2) 0.42; G(3) 0.47), and detectable heartbeats in IPS (X: G(1) 0.27; G(2) 0.25; G(3) 0.22). Treatment with oxytocin reduced the duration of the expulsion of the fetus, increased the number of IPS with ruptured umbilical cords and with severe meconium-stain degree and reduced the number of fetuses with inspiration attempts. Furthermore, the use of this hormone increased the need for obstetric assistance due to increased frequency of dystocia.

Lipidos hepática idiopática felina / Feline hepatic idiopathic lipidosis

En el presente trabajo se realiza una revisión de la literatura sobre el síndrome de lipidosis hepática idiopática felina. La patogenia de este síndrome en los gatos sólo se conoce parcialmente y está estrechamente relacionada con el metabolismo lipídico y proteínico; el estrés y la obesidad son los dos factores más comúnmente involucrados. Los signos clínicos generalmente comienzan con anorexia, pérdida progresiva de peso, depresión y hepatomegalia, acompañados por niveles elevados de la actividad de las enzimas hepáticas y de la bilirrubina en la sangre. Una vez diagnosticada la lipidosis hepática, se debe continuar con exámenes clínicos y de laboratorio para excluir otros procesos patológicos causantes de lipidosis hepática secundaria y así llegar al diagnóstico final de lipidosis hepática idiopática felina.

Efecto antiinflamatorio del líquido amniótico en el pulmón de ratas inoculadas intratraquealmente con sílice / Antiinflamatory efect of amniotic fluid in the lung of ratas intratracheally inoculated with silica

El síndrome de aspiración de meconio representa un estado patológico de gran importancia para la medicina humana; sin embargo, es poco conocido en medicina veterinaria. En los últimos años se han realizado varias investigaciones con el fin de esclarecer la importancia y patogénesis de este síndrome en los animales domésticos. Estudios recientes han surgido un posible efecto antiinflamatorio del líquido amniótico debido a que la aspiración de este líquido contaminado con queratina, la cual es un factor proinflamatorio, sólo induce una respuesta inflamatoria leve en el pulmón de becerros. El objetivo de esta investigación fue determinar si el líquido amniótico produce un efecto antiinflamatorio en los pulmones de ratas inoculadas intratraquealmente con sílice. Treinta y ocho ratas Wistar de 177 g en promedio se dividieron en cinco grupos. Cada grupos recibió vía intratraqueal diferentes dosis de líquido amniótico y solución salina fisiológica (0, 0.125, 0.250, 0.375 y 0.5 ml, respectivamente) y cantidades constantes de sílice (5 mg/ml). Los animales inoculados se sacrificaron a las 72 horas posinoculación y se realizaron lavados broncoalveolares. Se realizó la cuenta total de células nucleadas por ml de lavado, así como el porcentaje y cuenta absoluta de neutrófilos y macró fagos. La inoculación con sílice y líquido amniótico indujo un marcado incremento en la cuenta total de células nucleadas y en el número de neutrófilos (P < 0.01) en los grupos tratados respecto del testigo. El incremento se mostró como una función directa del volumen de líquido amniótico inoculado. Sin embargo, se concluyó que el líquido amniótico no tuvo un efecto antiinflamatorio en el pulmón de ratas inoculadas intratraquealmente con sílice