Experimental oral administration of pollen beetle (Astylus atromaculatus) to cattle results in an acute lethal gastrointestinal disease.

In the summer of 2023, ingestion of Astylus atromaculatus (pollen beetle) was linked to spontaneous fatal disease in grazing cattle and sheep in Argentina and Uruguay. While the disease was experimentally reproduced in sheep and guinea pigs in the 1970's, no experimental reproductions have been attempted in cattle, and controversy exists as to whether this insect is indeed noxious to cattle and at which dose. Here, we demonstrate that A. atromaculatus causes acute fatal disease in Hereford calves at single oral dosages of 2.5, 4.5, 10.0, and 15.0 g of insect/kg body weight. Death or severe disease necessitating euthanasia occurred at 38 to 48 hours postinoculation regardless of the dose, suggesting that the single fatal dosage is likely <2.5 g/kg body weight (this dose representing approximately 850 mL of intact beetles in a 100 kg calf). Clinically, the disease was characterized by acute anorexia, prolonged recumbency, reluctance to move, listlessness/apathy, depression, ruminal hypomotility and tympany, hypothermia, bruxism with frothing at the mouth, and mucoid diarrhea progressing to death. Hematologic and biochemical alterations included hemoconcentration, stress/acute inflammatory leukogram, negative energy balance, and ketosis. The pathological hallmark of this experimental disease is acute necrotizing omaso-reticulo-rumenitis, fibrinohemorrhagic enteritis, and exfoliative colitis with intralesional chitinous insect fragments. While A. atromaculatus might contain a gastrointestinal toxin or pathogen, extensive toxicological testing failed to identify a causative toxin. Other pathomechanisms such as direct physical damage caused by insect fragments on the alimentary tract seem plausible, although further studies are needed to elucidate the pathogenesis of A. atromaculatus-associated disease.

Diseases associated with bovine viral diarrhea virus subtypes 1a and 2b in beef and dairy cattle in Uruguay.

Bovine viral diarrhea virus (BVDV, Pestivirus) causes significant economic losses to the livestock industry worldwide. Although serological surveys show that BVDV exposure is widespread in cattle in Uruguay, BVDV-associated diseases are greatly underreported. The aim of this work is to describe the epidemiological, clinical, pathological, and virological findings from spontaneous outbreaks of BVDV-associated diseases in cattle in Uruguay. Diagnostic investigations were performed during 6 spontaneous disease outbreaks on beef and dairy cattle farms in the departments of Colonia, Rio Negro, and Soriano between November 2016 and April 2018. Carcasses of 8 naturally deceased cattle from these outbreaks were necropsied and subjected to histological examination and immunohistochemistry to detect BVDV antigen in the tissues. Reverse transcription real-time PCR and genomic sequencing were also performed to identify BVDV at the species and subtype levels. Other ancillary diagnostic tests, including bacterial cultures, were performed on a case-by-case basis to rule in/out differential diagnoses based on initial clinicopathological presumptive diagnoses. BVDV-associated conditions that were diagnosed in the 8 cases included mucosal disease, transient postnatal BVDV infections associated with digestive/septicemic salmonellosis by Salmonella serovar typhimurium, Histophilus somni bronchopneumonia, urinary tract coinfections with Escherichia coli and Streptococcus sp., enteric coinfection with coccidia, and transplacental fetal infections and abortions with Neospora caninum coinfection. BVDV-1a and BVDV-2b were each identified in four of the eight cases. We conclude that BVDV-1a and BVDV-2b contribute significantly to disease and mortality in cattle in Uruguay. Future research should estimate the economic impact of BVDV in the Uruguayan livestock sector.

High frequency of cutaneous squamous cell carcinoma in Friesian Milchschaf sheep in Uruguay / Alta frequência de carcinoma cutâneo de células escamosas em ovinos da raça Frisona Milchschaf no Uruguai

This study described five cases of squamous cell carcinoma (SCC) in the pinnae, eyelids, and eyes of Friesian Milchschaf sheep from two flocks raised under extensive conditions in Uruguay. The prevalence values for both flocks were 2.12% and 2.53%, respectively. Macroscopically, single or multiple, nodular, verrucous, or plaque-like neoplasms, with occasional ulceration and bleeding, were observed in the affected areas. Histologically, well- and moderately-differentiated SCCs were diagnosed in three and two cases, respectively. The Milchschaf breed is native of Germany, and its individuals present white non-pigmented skin with the face and legs clear of fleece, thus adapted to areas with lower solar radiation. Additionally, in the German breeding systems, animals remain indoors for long periods. The increased exposure time to higher levels of solar radiation of the Uruguayan extensive production systems may be a predisposing factor for the development of SCC in this sheep breed. In Uruguay, there is more solar radiation and the production systems provide less protection against sunlight compared with the German production system. The high frequency of SCC should be considered prior to introducing European breeds with non-pigmented skin in Uruguay and other countries of the region.(AU)

Descreveram-se carcinomas de células escamosas (CCE) nas orelhas, pálpebras e olhos em cinco ovinos da raça Frisona Milchschaf em dois rebanhos de criação extensiva no Uruguai. A prevalência nos rebanhos foi de 2,12% e 2,53%. Macroscopicamente se observaram lesões focais ou multifocais, com aumento de volume, nodulares, verrucosas ou em placas, com ocasionais ulcerações e hemorragias. Apresentavam aspecto verrucoso, por vezes com superfície ulcerada e firmes ao corte. De acordo com as características histológicas da neoplasia, as lesões foram classificadas em CCEs bem diferenciados em três casos e moderadamente diferenciados em dois casos. Esta raça é nativa da Alemanha, caracterizada pela face deslanada e pele branca despigmentada. Na Alemanha, há menores níveis de radiação solar do que no Uruguai e seu sistema de produção é mais intensivo, com permanência dos animais confinados durante longos períodos. O aumento do tempo de exposição a níveis mais elevados de radiação solar pode ser um fator predisponente para o desenvolvimento de CCEs nesta raça em sistemas extensivos de produção no Uruguai. Neste País há mais radiação solar e os sistemas produtivos fornecem menos proteção contra a luz solar, em relação ao sistema de produção alemão. A alta frequência de CEE deveria ser levada em consideração para quem decide introduzir no Uruguai e outros países da região. raças europeias com a face despigmentada.(AU)

Facial paralysis and vestibular syndrome in feedlot cattle in Argentina / Paralisia facial e síndrome vestibular de bovinos em confinamento

This paper reports 6 outbreaks of neurological disease associated with paralysis of the facial and vestibulocochlear nerves caused by intracranial space occupying lesions in feedlot cattle. The clinical signs observed were characterized by head tilt, uni or bilateral drooping and paralysis of the ears, eyelid ptosis, keratoconjunctivitis, and different degrees of ataxia. Morbidity and mortality rates ranged from 1.1 to 50 percent and 0 to 1 percent, respectively. Gross lesions observed included yellow, thickened leptomeninges, and marked enlargement of the roots of cranial nerves VII (facial) and VIII (vestibulocochlear). Histopathologically, there was severe, chronic, granulomatous meningitis and, in one case, chronic, granulomatous neuritis of the VII and VIII cranial nerves. Attempts to identify bacterial, viral, or parasitic agents were unsuccessful. Based on the morphologic lesions, the clinical condition was diagnosed as facial paralysis and vestibular syndrome associated with space occupying lesions in the meninges and the cranial nerves VII and VIII. Feedlot is a practice of growing diffusion in our country and this is a first report of outbreaks of facial paralysis and vestibular disease associated with space occupying lesions in Argentina.

Descrevem-se 6 surtos de uma doença neurológica com paralisia dos nervos facial e vestibulo-coclear causada por lesões intracraniais que ocupam espaço em bovinos em confinamento. Os sinais clínicos foram desvio da cabeça, queda e paralisia das orelhas, ptose palpebral, ceratoconjuntivite e diferentes graus de ataxia. As taxas de morbidade e mortalidade foram de 1.1 por cento-50 por cento e de 0-1 por cento, respectivamente. As lesões macroscópicas incluíram engrossamento das meninges, que se apresentavam amareladas, e marcado engrossamento das raízes dos nervos cranianos VII (facial) e VIII (vestíbulo-coclear). Histologicamente observaram-se meningite crônica granulomatosa e, em um caso, neurite granulomatosa crônica do VII e VIII pares cranianos. Cultivos para bactérias ou vírus resultaram negativos. De acordo com as lesões observadas o quadro clínico foi diagnosticado como paralisia facial e síndrome vestibular associadas a lesões que ocupam espaço nas meninges e nervos cranianos VII e VIII. O confinamento é uma prática em expansão na Argentina e este é o primeiro relato, neste país, de surtos de paralisia facial e síndrome vestibular associados com lesões que ocupam espaço.