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En nuestra nota editorial del primer semestre del año 2020 (Portiansky, 2020) hacíamos referencia a la reducción de las prácticas profesionales, tanto fuera como dentro de los laboratorios de nuestro país y del mundo, por causa de la pandemia de la COVID-19. En vista a ello, especulábamos acerca del caudal de material a ser publicado en los siguientes meses. La hipótesis indicaba que la mayoría de los trabajos no relacionados con diferentes aspectos del nuevo coronavirus sería el producto de experimentos realizados con anterioridad a la fecha del cierre de los establecimientos educativos y de investigación. Hoy nos encontramos a más de un año de aquella fecha inicial, en marzo de 2020, y vemos las consecuencias de lo mencionado: los trabajos presentados por los diferentes investigadores han disminuido, tanto en nuestra revista, como en muchas otras de nuestro país y del mundo. De acuerdo con la base de datos MEDLINE (https://pubmed.ncbi.nlm.nih.gov/), de las 115.637 citas correspondientes a la palabra clave “coronavirus”, 109.127 corresponden al bienio 2020-2021. Es decir, en el último año y medio se publicó el 94,3% del material acerca del virus y de los alcances de la infección. De esas cifras, 9732 trabajos referidos a animales no humanos fueron publicados entre 1949 y 2019, mientras que en los últimos 2 años se publicaron 4301 trabajos (44,2%) que, en su mayoría, probablemente correspondan a animales de experimentación. Sin embargo, para otros temas, la producción científica no reflejó los mismos índices. Si por ejemplo tomamos como palabras clave “mastitis bovina”, en el año 2020 se publicaron 271 artículos, mientras que en el año anterior (2019) se habían publicado 340. En el primer semestre del año 2020, se habían publicado 173 de los 271 (63,8%). Durante el primer semestre de este año 2021, solo se publicaron 58 trabajos en el tema. De la misma manera, se pueden realizar búsquedas de palabras clave generales acerca de procesos infecciosos, de producción o experimentación con animales y en la mayoría de los casos se va a observar un patrón similar, debido a que muchas experiencias iniciadas debieron ser suspendidas o retrasadas por las medidas sanitarias vigentes. No solo el cierre de los centros de investigación ha impactado negativamente en el caudal de publicaciones. Se le suma también el incremento del precio de los insumos, reactivos y equipamiento de investigación a nivel mundial, que repercute particularmente en nuestro país, donde los subsidios para la investigación no solo no se actualizan, sino que sufren retrasos de desembolso. Lentamente, los distintos países irán restableciendo las actividades experimentales a medida que la vacunación de la población permita retomar las actividades cotidianas. De esa manera, aquellas revistas que usualmente contamos con un número acotado de trabajos científicos iremos incrementando nuestro caudal de información para los más diversos lectores, hasta alcanzar nuestros valores históricos. Será un proceso paulatino, pero ANALECTA VETERINARIA estará abierta, como desde hace más de 115 años, a todos aquellos que quieran publicar en una revista de alcance nacional y americano en temas que hacen al saber científico en el área de las ciencias veterinarias.

La mieloencefalitis equina por protozoos (EPM) es causada por Sarcocystis neurona y genera importantes pérdidas económicas. En Argentina, se han detectado anticuerpos contra este protozoo, pero no se han reportado casos clínicos. Una yegua de 12 años, de la provincia de Buenos Aires presentó marcha asincrónica y arpeo bilateral. El animal fue tratado con fenitoína, vitamina B1, AINEs y tenectomía. El cuadro clínico fue progresivo con depresión, parálisis facial, atrofia de los músculos del dorso, lomo y miembros pelvianos, dismetría e inestabilidad de la marcha, temblores generalizados y tetraparesia, por lo que se decidió la eutanasia. Se observaron lesiones microscópicas en el tálamo, el metencéfalo y la médula espinal, y consistieron en pequeños focos múltiples hemorrágicos y focos de inflamación crónica. La inmunohistoquímica realizada en muestras de cerebro y médula espinal reveló la presencia de merontes y merozoitos de S. neurona. Mediante PCR-RFLP se observó un patrón de restricción específico de S. neurona en muestras de cerebro. La detección de anticuerpos contra S. neurona en caballos, la abundancia de comadrejas y la confirmación específica en este caso, sugieren que la enfermedad puede estar extendida en nuestro medio. Esta es la primera descripción de un caso de EPM en Argentina, confirmado mediante estudios histopatológicos, inmunohistoquímicos y moleculares., Equine protozoal myeloencephalitis (EPM) is mainly caused by Sarcocystis neurona and generates significant economic losses. In Argentina, antibodies to this protozoan have been detected but no clinical cases have been reported. A 12-year-old mare, from Buenos Aires Province, presented asynchronous walking and bilateral stringhalt. The animal was treated with phenytoin, vitamin B1, nonsteroid antiinflammatory drugs and subsequent tenectomy. Clinical outcome progressed to depression, facial paralysis, atrophy of the muscles of the back, loin and pelvic limbs, dysmetria and gait instability, generalized tremors and tetraparesis. Euthanasia was decided based on clinical progression and lack of response to treatment. Microscopic lesions were observed in thalamus, metencephalon and spinal cord, and consisted in small hemorrhagic multiple foci and small foci of chronic inflammation. Immunohistochemical analysis revealed the presence of intracellular S. neurona meronts and free merozoites in brain and spinal cord samples. The PCR-RFLP analysis showed a specific S. neurona restriction pattern in brain samples. Previous detection of antibodies to S. neurona in horses, the abundance of opossums in the region and the specific confirmation in this case, suggest that the disease may be widespread in Argentina. This is the first EPM case report in Argentina, confirmed by histopathologic, immunohistochemical and molecular studies., Facultad de Ciencias Veterinarias

Spontaneous invasive non-inflammatory canine mammary carcinomas (CMC) and their regional lymph nodes (LN) were analysed (n = 136). Histological grade (HG) and vascular invasion (VI) in the tumours and lymph node status were recorded. Proliferation index (PI), microvessel density (MVD) and vascular endothelial growth factor receptor 2 (VEGFR2) expression were estimated using anti-proliferating cell nuclear antigen (PCNA), anti-von Willebrand factor and anti-Flk-1, respectively. Eighteen months follow-up was performed (34 bitches). Tumours of different grades showed differences regarding PI, Flk-1/integrated optical density (Flk-1/IOD) and MVD. Every feature showed significant association with LN status through bivariate analyses. From multivariate analyses, VI and Flk-1/IOD were selected to predict LN status. Data revealed that the probability of a CMC-bearing bitch to remain alive at 1, 4, 5 and 14–18 months was 0.91, 0.87, 0.81 and 0.77, respectively. Besides LN status, VI was the only feature positively correlated with survival time, although a trend to shorter survival of animal patients bearing high expressing VEGFR2 CMC was noted. Fil: Diessler, Mónica Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas; Argentina Fil: Castellano, M.C.. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina Fil: Portiansky, Enrique Leo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Cátedra de Patología General Veterinaria; Argentina Fil: Burns, Sarah. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Investigación en Sistemas Ecológicos y Ambientales; Argentina Fil: Idiart, Julio Roberto. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Cátedra de Patología Especial; Argentina

A 10-year-old male Briard dog was presented because of listlessness, abnormal gait, fever, inappetence, and seizures. A non-pigmented growth was observed in the ventral quadrant of the left iris. Thoracic radiographs revealed multiple pulmonary metastases and the owner opted for killing. On necropsy, lung masses and nodules in left iris, right adrenal medulla, and brain were detected. Histologically the primary tumour was diagnosed as pulmonary adenocarcinoma with predominant solid pattern. Metastases to regional lymph nodes, uvea, adrenal medulla, and brain were recognized. The metastatic behaviour resembled that occurring in humans. To the authors' knowledge, this is the first report of a pulmonary adenocarcinoma with metastasis to the uvea in a dog.

Lymphangiosarcoma is a rare tumour in domestic animals arising from lymphatic endothelial cells. Occasionally, microscopic differentiation with haemangiosarcoma may be difficult. The aim of the present study was to describe a lymphangiosarcoma in a 1-year-old female Doberman Pinscher dog and to characterize its lectinhistochemical binding pattern as compared with that of haemangiosarcoma. The dog was presented because of a cutaneous painful swelling located in the left axilla. Histological diagnosis confirmed lymphangiosarcoma. The dog was killed. Necropsy revealed mediastinal lymph nodes' involvement. Twenty lectins were tested in tissue sections of this case as well as in four haemangiosarcomas from other dogs. Staining intensity was issued upon optical density determinations. Percentage of lectinhistochemical staining area was also conducted. RCA-I showed the most intense and wide distributed labelling pattern for lymphangiosarcoma. PHA-E was the counterpart for haemangiosarcoma. Should similar results be obtained in further studies, such differences could aid in the differential diagnosis between lymphangiosarcoma and haemangiosarcoma when histological pictures were not conclusive.

Apoptotic index (AI) of the gastrointestinal mucous epithelia was examined in mice at 8, 16, 24 and 48 hours after oral inoculation (HAI) of T-2 toxin (10mg/kg). In the fundic region of the stomach, AI prominently increased at 8 HAI and deceased thereafter in the foveolae gastricae while it started to increase slowly and became prominent at 24 HAI in the glandular base. AI in the glandular neck was constantly low. On the other hand, in the intestinal crypt epithelia, AI prominently increased at 8 HAI in all regions examined (duodenum, ileum, cecum and colon), and thereafter decreased with the lapse of time. AI was clearly higher in the small intestine than in the large one especially in the early stage. Mitotic index (MI) examined was drastically decreased at 8 HAI when AI prominently increased, and thereafter turned to recover in the lapse of time. However AI after T-2 toxin inoculation was not always proportional to MI before T-2 toxin inoculation. The sequence of and the regional difference in AI in the gastrointestinal mucous epithelia after T-2 toxin intoxication was first clarified in the present study.

Summary Double immunoenzymatic labelling made possible the simultaneous staining of two antigens with a mixture of polyclonal and monoclonal commercial antibodies. Immunocharacterization of intermediate filament proteins was found to be an accurate indicator of histogenesis in urinary bladder tumours of cattle.

Renal changes in mice daily treated with low doses of ochratoxin A (OA; 50-400μg/kg) for up to 4 weeks were investigated by electron microscope. Except the mice treated with 50μg/kg of OA for 4 weeks, all treated mice showed the following changes in the epithelial cells of Henle's loop: (1) degeneration of mitochondria, (2) increment of endoplasmic reticula, and (3) increase in the number and size of lysosomes and myelin figures., Facultad de Ciencias Veterinarias

Peripheral neuroblastoma (PNB) is a rare neoplasia derived from neuroepithelial cells. PNB typically presents as a greyish mass, composed of round cells with features of neuronal differentiation. Necropsy, performed on a 1-day-old piglet, revealed a mass craniodorsally located in the abdominal cavity. Histologically, the predominant population consisted of small round to ovoid cells with scanty cytoplasm and dark round nuclei, besides, there were larger neurone-like cells. Neurone-specific enolase and S-100 protein were immunohistochemically detected, while glial fibrillary acidic protein was negative. Histological and immunohistochemical findings substantiated the diagnosis of a grade II peripheral neuroblastoma. This seems to be the first description of a PNB in a newborn piglet.

The prognostic significance of angiogenesis in some canine tumours has been investigated, but little is known about its relevance in canine melanocytic tumours (MTs). The aim of this study was to evaluate the prognostic significance of angiogenesis in canine MTs. A total of 36 cutaneous melanocytomas (benign MTs), 40 cutaneous melanomas (malignant MTs) and 43 oral melanomas were studied. Survival data were available for a subset of 59 cases. Microvessel density (MVD) and endothelial area (EA) were determined by immunolabelling using an antibody specific for von Willebrand factor (vWF). Mean MVD (expressed as the number of microvessels per mm(2)) was 129 ± 14 in melanocytomas, 191 ± 16 in cutaneous melanomas and 208 ± 16 in oral melanomas. Mean EA (expressed as the percentage of the total area) was 1.5 ± 0.14 in melanocytomas, 2.6 ± 0.2 in cutaneous melanomas and 2.4 ± 0.3 in oral melanomas. The differences in MVD and EA between melanocytomas and melanomas were significant (P = 0.001 and P = 0.003, respectively). MVD and EA were significantly correlated between cutaneous and oral MTs (r = 0.54; P0.001 and r = 0.63; P0.001, respectively). MVD and EA were not related to survival in cutaneous and oral MTs. In conclusion, tumour vascularization was higher in melanomas than in melanocytomas, but it seemed to have no prognostic significance in these tumours.

The objectives were to determine the prevalence of fibrinonecrotic enteritis (FNE) on a farrow-to-finish farm of 1,000 sows, to categorize the pathological changes, and to to investigate the lesion associated agents Isospora suis and Clostridium perfringens. Causes of preweaning mortality (PWM) were classified into 8 categories including FNE. Obtained data were evaluated for statistical significance by adjusted Chi-square analysis. Samples of FNE were taken for complementary studies including a PCR technique for genotyping toxin genes of Clostridium perfringens from gut samples fixed in 10% neutral formalin. From 3,153 piglets examined, less than 1% was classified as FNE. FNE prevalence increased progressively from the first to the third week, the last differing statistically from the others. Eighty percent of gut samples with FNE lesions were positive to Isospora suis, when examined by PCR from 9 severe FNE lesions detected 7 positive samples only for a toxin gene, characteristic of C. perfringens type-A. Os objetivos deste trabalho foram determinar a prevalência de enterite fibrinonecrótica (EFN) em uma granja tecnificada com 1000 matrizes, classificar as mudanças patológicas e investigar a lesão decorrente da associação dos agentes Clostri-dium perfringens e Isospora suis. As lesões macroscópicas devidas à mortalidade pré-desmame (MPD) foram classificadas em oito categorias incluindo EFN. Os dados obtidos foram avaliados pelo teste Qui-quadrado. Amostras de EFN foram colhidas para estudos complementares incluindo uma técnica de reação em cadeia da polimerase (PCR) para identificação dos genes codificadores de toxinas de C. perfringens a partir de amostras do intestino fixadas em formalina a 10%. Dos 3.153 leitões examinados, menos que 1% foram classificados como EFN. As análises estatísticas revelaram que a EFN aumentou progressivamente a partir da primeira para a terceira semana, sendo que a última semana diferiu estatisticamente das demais. Oitenta porcento das amostras do intestino com EFN foram positivas para I. suis. Por meio da PCR a partir dos 9 casos de EFN severa, 7 foram positivos somente para o gene da toxina alfa, característico de C. perfringens tipo A.

Se realizo un estudio sobre las caracteristicas macro y microscopicas del corazon y grandes vasos de coipos (Myocastor coypus, Molina) de diferentes edades. Asimismo, se estudiaron macroscopicamente las venas superficiales, de probable aplicacion en la venopuncion. Se utilizaron 44 animales de ambos sexos, incluyendo adultos, prepuberes, recien nacidos y fetos de 120 dias de gestacion. El corazon y los grandes vasos de 18 animales adultos y prepuberes y de 14 recien nacidos, asi como las venas cefalica y safenas lateral y medial de los adultos y prepuberes, fueron disecados, medidos y fotografiados. Tambien se tomaron muestras de corazon y aorta de animales de todas las edades, las que se fijaron y procesaron histologicamente con los metodos clasicos, para luego colorearlas con hematoxilina y eosina, picrosirius-red , hematoxilina ferrica de Verhoeff y resorcina-fucsina de Weigert, con y sin oxidacion previa con oxona. Los resultados obtenidos indican que el corazon y los grandes vasos son, en general, similares al de otros roedores, aunque con algunas caracteristicas propias. El peso relativo del corazon oscilo entre 0,93 % y 1,03 %. Las venas mas apropiadas para la venopuncion resultaron ser la cefalica y la safena lateral. El sistema de fibras resulto similar en los adultos y prepuberes a otros roedores. En los fetos, cuando fueron comparados con los recien nacidos, se constataron diferencias de cantidad y de distribucion, sobre todo en las fibras del sistema elastico

Summary The horn fly Haematobia irritans L. (Diptera: Muscidae) has recently spread to Argentina and Uruguay and is believed to cause damage to cattle hides. Four groups of ten Holstein steers each were maintained for 58 weeks under different infestation levels with H. irritans to determine if it was the cause of this problem. Hides (chrome tanned) from steers maintained under minimum infestation level had 4.7 ± 3.8% of the area damaged. Maintaining the steers under low H. irritans level for the last 44 days of the trial using insecticidal ear-tags, resulted in 29.5 ± 15.8% of hide area being damaged. Steers that were treated with 5% cypermethrin pour-on, when the H. irritans population was close to 50 flies, showed that 31.3 ± 16.6% of hide area was injured, and 46.6 ± 12.8% of damaged hide area was found in hides from non-treated steers. Significant differences were found between mean hide damage from steers maintained continuously under low H. irritans infestation levels and all other groups. Hyperaemia was significantly lower in the skin of steers under low H. irritans infestation level than in the skins of non-treated steers and steers maintained under low-level infestations for the final 44 days. Eosinophil and mononuclear cell infiltration was significantly lower when the population of H. irritans was less than six per steer than when the population was more than 100 flies per steer. Low numbers of Stomoxys calcitrans were found in all groups, but most hide damage was presumed due to H. irritans.

RESUMEN:Fue realizada la disección del saco anal de 44 coipos, de ambos sexos, de distintas edades y procedencias, observándose algunas características similares a los sacos anales del perro y gato, aunque es impar y está ubicado en ventral del ano. Es ovoídeo o piriforme, siendo más grande en los adultos y, entre éstos, más aún en los machos que en las hembras; posee un conducto que desemboca en el canal anal a un centímetro del ano y que se exterioriza en el momento de secretar el producto glandular. Se encuentra rodeado de una cápsula de tejido fibroso e insertado en ella se observa tejido muscular estriado, correspondiente a fibras de los músculos del diafragma pelviano. Microscópicamente está constituido por un tejido glandular tubuloalveolar, con células globosas de núcleo laxo, con uno o más nucleolos. Desde la cápsula hacia el interior se forman tabiques de tejido conectivo que dividen al tejido glandular en lóbulos y lobulillos. Mediante coloraciones especiales se constató la presencia de fibras que contienen colágeno de los tipos I y III, de fibras eleunínicas y oxitalánicas. SUMMARY: The dissection of the anal sac of 44 coypus was done in both sexes but of different age and origin, showing some similar characteristics to those of the dog and the cat, although it is unpaired and located ventral to the anus. It is ovoid or pyriform, and larger in adults being bigger in males than in females. A main duct which empties into the anal canal just one centimetre from the anus can be seen when the glandular product is excreted. It is completely surrounded by a thin fibrous capsule with striated muscular attachments corresponding to the pelvic diaphragm. Microscopically it is composed of tubuloalveolar glands. Secretory cells are globoid-shaped with a centrally located round, pale-staining nucleus with prominent nucleoli. Delicate connective tissue septa separate the parenchyma into distinct lobes and lobules. Special stains reveal collagen fibers types I and III, and elauninic and oxitalanic fibers.

Immunocharacterization of intermediate filament proteins and lectin-binding studies were carried out in canine transmissible venereal tumour (TVT), a unique neoplasia sharing some epidemiological features with Kaposi's sarcoma in humans. Neoplastic cells express vimentin, but neither cytokeratin nor desmin. Regarding lectins, TVT cells express receptors for Triticum vulgaris (WGA), Concanavalia ensiformis (Con A) and Ricinus communis I (RCA-I). They appear to be negative for Ulex europaeus-I (UEA-I), Arachis hypogaea (PNA), Glycine maximus (SBA) and Dolichos biflorus (DBA).