Pythiosis is a disease widely distributed worldwide caused by Pythium insidiosum. It is transmitted and propagated in semi-aquatic environments, mainly affecting equines, canines, felines, cattle and humans. In Paysandu County, Uruguay, in the month of May 2017, a case of pitiosis was registered in a 24-year-old Creole breed female equine. An extensive circular lesion located in the ventral abdominal area was surgically removed. Macroscopically, it was observed granulation tissue, multifocal areas of necrosis with suppurative hemorrhagic content and yellowish-white pasty to chalky concretions. At the histopathological examination with HE in superficial and deep dermisthere were severe proliferation of connective tissue, neovascularization, multifocal areas of necrosis surrounded by infiltration of polymorphonuclears, mainly eosinophils, and macrophages. Inside of the areas of necrosis there was presence of hyphae stained positively by the argentic Grocott stain. Positive immunostaining was obtained for P. insidiosum. In the culture of the fresh material, colonies of whitish color and radial growth were isolated with the development of aerial mycelia after 48 hours. The isolation of P. insidiosum was confirmed by the induction of zoospores and the characterization of them. The ITS region (ITS1, 5.8S, ITS2) was amplified by the nested PCR reaction and in a second reaction the gene specific for P. insidiosum from the ITS1 region was amplified. The sequence obtained was compared with that registered in GenBank confirming a 100% homology with P. insidiosum.

A total of 53 farms were selected in Southern dairy region of Uruguay, in order to estimate the prevalence of subclinical mastitis, the incidence of clinical mastitis, distribution and antimicrobial susceptibility of mastitis pathogens. The prevalence of sub-clinical mastitis was determined in base on somatic cell counts in quarter’s milk samples and a threshold value of > 300,000 cells/ mL.; 9,016 milk quarters samples were collected from 2,254 dairy cows and the mean prevalence at herd level was 54.2% of affected cows. The main pathogen isolated from positive samples was Staphylococcus aureus (21.4%). During one with a mean incidence rate of clinical mastitis of 11.8 cases per 100 cow/year at risk. Milk samples were obtained from 341 clinical cases for bacteriological isolation, the most prevalent pathogen isolated was Staphylococcus aureus (27.8%). A total of 864 strains belonging to staphylococci, streptococci and enterococci isolated from clinical and subclinical mastitis cases were analyzed for their susceptibility to antimicrobial agents. The susceptibility patterns were studied by Agar disk diffusion method. The 39.1% of Staphylococcus aureus strains from subclinical cases and 36% from clinical cases were resistant to penicillin, and 29.4% and 33.3% of coagulase negative staphylococci strains, respectively. All the streptococcal isolates were susceptible to penicillin, while 12.5% of enterococci strains were resistant. In conclusion, Uruguay maintain a high level of sub clinical infection in the dairy herds, and Staphylococcus aureus is confirmed as the principal pathogen with a high percentage of penicillin resistance.

Twenty-nine dairy farms were selected to determine the incidence of clinical mastitis, prevalence of sub-clinical mastitis and bacterial aetiology in the West Littoral Region of Uruguay. In samples taken by the owner and frozen at -20°C during a week the incidence rate of clinical mastitis was determined as 1.2 cases per 100 cow-months at risk. Staphylococcus aureus was the most common isolated pathogen in 37.5% of 40 milk samples from clinical cases obtained in 1 month. No bacteria grew in the 32.5% of the total samples. A sub-sample including 1077 dairy cows from randomly selected farms was used to determine the prevalence of sub-clinical mastitis. These samples were taken on one visit to each farm. The prevalence was 52.4% on a cow basis and 26.7% on an udder quarter basis. In 55.1% of the quarters of the selected animals with more than 300 000 cells/ml there was no growth. The isolated pathogens from sub-clinical cases and their relative frequencies were: Staphylococcus aureus 62.8%, Streptococcus agalactiae 11.3%, Enterococcus sp. 8%, coagulase-negative staphylococci 7.4%, Streptococus uberis 6.4%, Streptococcus dysgalactiae 1.8%, Escherichia coli 1.5% and Staphylococcus hyicus coagulase-positive 0.6%.

Outbreaks of Anagallis arvensis poisoning were observed from 1994 to 1998 in cattle and sheep in Uruguay during December and January. Cattle morbidity varied between 3.2 and 53.2% and lethality 42.6 and 100%. Sheep morbidity was 2.8 to 42.9% and lethality 81.3 to 100%. Nine outbreaks occurred on barley and wheat stubble, and 1 in a field previousy ploughed but not cultivated. Clinical signs were weakness, staggers, diarrhea (sometimes bloody), coma, and death. Serum levels of creatinine and urea were elevated. Gross lesions were characterized by sc petechiae, fluid in body cavities, mesenteric and perirenal edema, yellowish or pale kidneys with petechiae on the cortex, esophageal erosive lesions or ulcers, and hemorrhagic abomasitis and enteritis. Severe nephrosis was observed histologically. The green plant collected in a field where an outbreak occurred was administered to 2 sheep at doses of 160 and 224 g/kg bw and produced clinical signs and pathology similar to those observed in field cases.