Spontaneous intoxication of sheep by the pollen beetle Astylus atromaculatus: 4 outbreaks in Uruguay and Argentina.

Astylus atromaculatus Blanchard is a native beetle of South America that feeds on pollen. During the summer of 2022-2023 in Argentina and Uruguay, an explosive infestation of these insects occurred in pastures in which ruminants were grazing. This was believed to be associated with a severe drought, which had significantly reduced the flowering of crops. Three farms in Uruguay and one in Argentina were visited to examine the flocks and perform autopsies. Affected sheep had watery diarrhea, anorexia, depression, and ruminal atony. The average morbidity, mortality, and case fatality rates were 7.5%, 4.3%, and 68%, respectively. The main gross findings in all animals were in the jejunum; the serosa had multifocal hemorrhages, and the mucosa was necrotic and covered by a pseudomembrane. Microscopically, the mucosa had partial-to-complete necrosis of the lamina propria, as well as loss of villus and crypt epithelium with neutrophilic infiltration. Overlying the necrotic mucosa was a pseudomembrane of fibrin, cell debris, desquamated epithelial cells, degenerate neutrophils, and bacteria. Many specimens of A. atromaculatus were in all paddocks in which sheep grazed, as well as in the ruminal content of the autopsied animals.

Solanum glaucophyllum intoxication in goats: Case study.

Solanum glaucophyllum is a toxic plant with calcinogenic effect that causes enzootic calcinosis (EC) characterized by soft tissue metastatic mineralization mainly in cattle and rarely sheep, buffaloes, pigs, horses, and goats. We describe an outbreak of EC in a herd of 64 goats due to S. glaucophyllum consumption. Thirty-four goats were affected exhibiting hirsutism, stiffening, kyphosis and emaciation. Twelve goats died. Grossly, tissue mineralization was observed in the aorta and carotid arteries, lungs, and heart. Lesions were characterized by multiple rough white plaques, and hardened tissues with loss of elasticity. Microscopically, multisystemic mineralization was observed in aorta and carotid arteries, heart, lung, abomasum, intestine, spleen, lymph nodes, kidney, spleen, and meninges, characterized by extensive granular basophilic deposits of tunica media and/or intima of blood vessels; confirmed as calcium salt deposits with Von Kossa stain. We conclude that ingestion of S. glaucophyllum can cause EC in goats. Though EC is rare in goats under some conditions such as heavy drought and abundant S. glaucophyllum exposure disease can develop.

Amaranthus hybridus (syn. quitensis) intoxication in cattle in Argentina: Case report.

Amaranthus spp. is a nephrotoxic plant with unknown toxic principle, affecting production animals worldwide, mainly in South America. The aim of this paper is to describe 5 spontaneous outbreaks of A. hybridus intoxication in beef cattle, where 7 autopsies were performed. Main gross findings were pale diffuse and enlarged kidneys. Microscopically, kidneys were characterized by severe tubular acute to subacute nephrosis, with dilatated tubules showing different degrees of epithelial degeneration and necrosis, and containing intraluminal eosinophilic hyaline casts. Intratubular birefringent crystals, compatible with oxalate, were observed under polarized light in kidneys from 3 autopsies. Positive von Kossa and red alizarin S staining confirmed the intratubular crystals as calcium deposits. This intoxication occurs mainly in stubble paddocks during summer and early autumn. The data from the present study suggests that oxalates were related to nephrotoxicity due to Amaranthus consumption.

Phylogenomic analysis for Campylobacter fetus ocurring in Argentina.

BACKGROUND AND AIM: Campylobacter fetus is one of the most important pathogens that severely affects livestock industry worldwide. C. fetus mediated bovine genital campylobacteriosis infection in cattle has been associated with significant economic losses in livestock production in the Pampas region, the most productive area of Argentina. The present study aimed to establish the genomic relationships between C. fetus strains, isolated from the Pampas region, at local and global levels. The study also explored the utility of multi-locus sequence typing (MLST) as a typing technique for C. fetus. MATERIALS AND METHODS: For pangenome and phylogenetic analysis, whole genome sequences for 34 C. fetus strains, isolated from cattle in Argentina were downloaded from GenBank. A local maximum likelihood (ML) tree was constructed and linked to a Microreact project. In silico analysis based on MLST was used to obtain information regarding sequence type (ST) for each strain. For global phylogenetic analysis, a core genome ML-tree was constructed using genomic dataset for 265 C. fetus strains, isolated from various sources obtained from 20 countries. RESULTS: The local core genome phylogenetic tree analysis described the presence of two major clusters (A and B) and one minor cluster (C). The occurrence of 82% of the strains in these three clusters suggested a clonal population structure for C. fetus. The MLST analysis for the local strains revealed that 31 strains were ST4 type and one strain was ST5 type. In addition, a new variant was identified that was assigned a novel ST, ST70. In the present case, ST4 was homogenously distributed across all the regions and clusters. The global analysis showed that most of the local strains clustered in the phylogenetic groups that comprised exclusively of the strains isolated from Argentina. Interestingly, three strains showed a close genetic relationship with bovine strains obtained from Uruguay and Brazil. The ST5 strain grouped in a distant cluster, with strains obtained from different sources from various geographic locations worldwide. Two local strains clustered in a phylogenetic group comprising intercontinental Campylobacter fetus venerealis strains. CONCLUSION: The results of the study suggested active movement of animals, probably due to economic trade between different regions of the country as well as with neighboring countries. MLST results were partially concordant with phylogenetic analysis. Thus, this method did not qualify as a reliable subtyping method to assess C. fetus diversity in Argentina. The present study provided a basic platform to conduct future research on C. fetus, both at local and international levels.

Occurrence of squamous cell carcinoma in Milchschaf sheep in Uruguay / Ocorrência do carcinoma de células escamosas em ovinos Milchschaf em Uruguai

ABSTRACT: In this study, the epidemiological and pathological features of an outbreak of squamous cell carcinoma (SCC) in adult female sheep and a young ram, Friesian Milchschaf breed or crossbreed is described. Seven adult females belonging to an original flock nucleus of 20 animals were affected, as well as a young ram belonging to the same nucleus was affected in other establishment. Multiple verrucous neoplastic masses of several months of evolution were evident in the head region, with local invasion and regional lymph node metastases. Histological studies revealed a cancerous stage of invasion of the dermis and neoplastic proliferation characteristic of invasive SCC, and a pre-cancerous stage with solar elastosis and chronic solar keratosis lesions induced by sunlight. Decrease in latitude, increased level of solar radiation with long exposure to sunlight, and the phenotypic characteristics of the breed are the main factors responsible for the high prevalence of SCC, showing the susceptibility of the Friesian Milchschaf breed and crossbreed in temperate zones as Uruguay.

RESUMO: Neste estudo descrevem-se as características epidemiológicas e patológicas de um surto de carcinoma de células escamosas (SCC) em ovelhas adultas e ram jovem, raça Friesian Milchschaf ou cruza. Foram afetadas sete fêmeas adultas pertencentes a um núcleo de rebanho original de 20 animais, bem como um ram jovem pertencente ao mesmo núcleo em que foi afetado em outro estabelecimento. Múltiplas neoplásicas verrucosas de vários meses de evolução foram evidentes na região principal, com invasão local e metástases de linfonodos regionais. Estudos histológicos revelaram um estágio cancerígeno de invasão da derme e proliferação neoplásica característica do SCC invasivo e um estágio pré-cancerígeno com elastose solar e lesões de ceratose solar crônica induzidas pela luz solar. A diminuição da latitude, o aumento do nível de radiação solar com longa exposição à luz solar e as características fenotípicas da raça são os principais fatores responsáveis pela alta prevalência de SCC, mostrando a susceptibilidade da raça Friesian Milchschaf e cruzada em zonas temperadas como o Uruguai.

A survey of Senecio spp. affecting livestock in Uruguay and their associated pyrrolizidine alkaloid content / Senecio spp. Afetando a pecuária no Uruguai e sua associação com alcaloides pirrolizidínicos

ABSTRACT: In Eastern Uruguay there has been a significant increase of seneciosis in grazing livestock with most affected localities related to counties neighboring the Brazilian border. A survey in 28 farms associated with poisoning outbreaks in grazing cattle in Eastern Uruguay was carried out. Fifty populations of Senecio plants were collected for alkaloid analysis and species identification. Four species were identified: S. oxyphyllus DC, S. madagascariensis Poir, S. brasiliensis (Spreng.) Less., and S. selloi DC. Alkaloids were identified by a combination of GC-MS and HPLC-MS analysis and included: retrorsine in S. oxyphyllus; retrorsine, usaramine, and senecivernine/senecionine in S. selloi; retrorsine, senecivernine/senecionine, integerrimine, and usaramine in S. madagascariensis; and integerrimine, retrorsine and senecionine in S. brasiliensis. Total mean alkaloid concentration was reported to be highest in S. brasiliensis (17.6mg/g) followed by S. oxyphyllus (6.2mg/g), S. selloi (1.8mg/g) and S. madagascariensis (0.6mg/g). Alkaloid concentrations were also reported to be higher in 2015 vs. 2016 probably due to a common environmental factor. The species S. oxyphyllus and S. madagascariensis were not previously recognized as toxic plants in Eastern Uruguay. Particularly, S. oxyphyllus was present in 82% of the farms surveyed and occurred in high density with relative high concentrations of pyrrolizidine alkaloids suggesting S. oxyphyllus may be the main species involved in the reported outbreaks of seneciosis.

RESUMO: No leste do Uruguai houve um aumento significativo da seneciosis no gado de pastagem com a maioria das localidades afetadas em municípios vizinhos à fronteira brasileira. Aplicou-se um questionário em 28 fazendas associadas a surtos de intoxicação em bovinos de pastagem na fronteira leste do Uruguai. Coletaram-se cinquenta populações de Senecio para análise de alcalóides e identificação de espécies. Identificaram-se quatro espécies: S. oxyphyllus DC, S. madagascariensis Poir, S. brasiliensis (Spreng.) Less. e S. selloi DC. Identificaram-se os seguintes alcalóides mediante análise combinado de GC-MS e HPLC-MS: retrorsina em S. oxyphyllus; retrorsina, usaramina e senecivernina/senecionina em S. selloi; retrorsina, senecivernina/senecionina, integerimina e usaramina em S. madagascariensis; e integerrimina, retrorsina e senecionina em S. brasiliensis. A concentração média total de alcalóides foi mais elevada em S. brasiliensis (17,6mg/g) seguido de S. oxyphyllus (6,2mg/g), S. selloi (1,8mg/g) e S. madagascariensis (0,6mg/g). As concentrações de alcaloides foram maiores em 2015 em vista à 2016, provavelmente, devido a um fator ambiental comum. As espécies S. oxyphyllus e S. madagascariensis não foram previamente reconhecidas como plantas tóxicas no leste do Uruguai. Particularmente, S. oxyphyllus esteve presente em 82% das fazendas pesquisadas e ocorreu em alta densidade com concentrações relativamente elevadas de alcalóides de pirrolizidina sugerindo que S. oxyphyllus pode ser a principal espécie envolvida nos surtos relatados de seneciosis.

White muscle disease in three selenium deficient beef and dairy calves in Argentina and Uruguay / Doença do músculo branco em três bezerros para carne e leite deficientes em selênio na Argentina e Uruguai

ABSTRACT: White muscle disease (WMD), nutritional myodegeneration or enzootic muscular dystrophy, is a nutritional condition associated with selenium and/or vitamin E deficiency in ruminants. These elements are constituents of the major body antioxidant systems. Depletion of selenium results in oxidative damage to cardiac and skeletal muscle cells, resulting in myodegeneration and myonecrosis, typical lesions of WMD. Selenium deficiency is common in South America, but WMD is underreported. This research describes clinical, biochemical and pathological findings in two episodes of WMD associated with selenium deficiency in beef and dairy calves in Argentina and Uruguay with concurrent copper deficiency in one of them, which resulted in spontaneous calf mortality. Further studies are necessary to estimate the true incidence and economic impact of clinical and subclinical mineral deficiencies in livestock production systems in the southern cone of South America.

RESUMO: Doença do músculo branco (DMB), miodegeneração nutricional ou distrofia muscular enzoótica é uma condição nutricional associada à deficiência de selênio e/ou vitamina E em ruminantes. Esses elementos são constituintes dos principais sistemas antioxidantes do corpo. O esgotamento de selênio resulta em dano oxidativo às células musculares cardíacas e esqueléticas, resultando em miodegeneração e mionecrose, lesões típicas da DMB. A deficiência de selênio é comum na América do Sul, mas a DMB está subnotificada. Este trabalho descreve os achados clínicos, bioquímicos e patológicos em dois surtos de DMB associados à deficiência de selênio em bezerros para carne e leite na Argentina e Uruguai com concomitante deficiência de cobre em um surto, que resultaram em mortalidade espontânea de bezerros. São necessários mais estudos para estimar a verdadeira incidência e impacto econômico das deficiências minerais clínicas e subclínicas nos sistemas de produção pecuária no sul da América do Sul.