Publications by authors named "Melissa Macias Rioseco"

Article Synopsis
  • Associated abomasitis is identified as a possible cause of sudden death in lambs, but its characteristics are not well understood.
  • A study described severe fibrinonecrotizing abomasitis in three lambs, highlighting pathological features like thickened submucosa, necrotic areas, and the presence of gram-negative coccobacilli.
  • Clostridial co-infection was suggested, with additional complications seen in two lambs, indicating the need to include this condition in differential diagnoses for necrotizing abomasitis in lambs.
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In animals, salmonellosis is seen typically as enteritis and/or septicemia. Subclinical infection also occurs, and outwardly healthy animals can serve as reservoirs of infection. Reports of salmonellosis in elephants are rare, limited to a few serovars, and the gross and microscopic lesions of enteric salmonellosis in this species have not been described in detail.

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Coccidioidomycosis is a fungal disease caused by or . We searched the records of the California Animal Health and Food Safety Laboratory from 1990 through 2020 for cases of coccidioidomycosis in horses. The selection criteria for these cases were: 1) live-born horses submitted for autopsy, and 2) a diagnosis of coccidioidomycosis was established, regardless of cause of death.

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Cattle are broadly deemed a source of ; however, evidence reinforcing their role in human infection is scarce. Most published human Q fever outbreaks relate to exposure to small ruminants, notably goats. Anti-phase II IgG and IgM were measured by indirect fluorescent antibody tests in 27 farm and veterinary diagnostic laboratory workers to ascertain whether occupational exposure to cattle aborting due to was the probable source of exposure.

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Article Synopsis
  • - Rabbit haemorrhagic disease virus type 2 (RHDV2) causes serious liver disease in not just European rabbits, but also in other rabbit species like hares and cottontails.
  • - The virus emerged in Europe in 2010 and has led to numerous outbreaks across North America since it was first detected there in 2016, with a significant outbreak occurring between 2020 and 2021 in the southwestern USA and Mexico.
  • - A study in California found that 33 out of 81 rabbits and hares tested positive for RHDV2, showing signs of liver damage typical for the infection, while genome sequencing revealed the virus strains were closely related to those from the ongoing outbreak in
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Coxiella burnetii is a highly transmissible intracellular bacterium with a low infective dose that causes Q fever (coxiellosis), a notifiable zoonotic disease distributed worldwide. Livestock are the main source of C. burnetii transmission to humans, which occurs mostly through the aerogenous route.

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Objective: To determine incidences and underlying causes of fatal intestinal inflammatory lesions (FIILs) and demographic characteristics of affected equids necropsied at any of the California Animal Health and Food Safety Laboratory facilities between January 1, 1990, and April 16, 2013.

Animals: 710 equids with FIILs, including colitis, duodenitis, enteritis, enterocolitis, enteropathy, enterotyphlitis, gastritis, gastroenteritis, ileitis, jejunitis, typhlitis, or typhlocolitis, alone or in combination.

Procedures: The medical records were reviewed, and data collected included animal age, sex, geographic origin, necropsy submission date, and breed, purpose, or characteristic of use.

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Bovine abortion causes considerable economic losses to the livestock industry worldwide and is of concern for public health and food safety, given that many abortigenic infectious agents of cattle are zoonotic. Despite its importance, the etiological diagnosis of abortion in cattle is challenging both for veterinary practitioners and laboratory technicians, partly due to the difficulty in recovering aborted fetuses under extensive field conditions for pathological and microbiological diagnostic investigation, and in the early identification of aborted dams. Neospora caninum is a cosmopolitan protozoon identified as one of the main abortigenic agents in cattle worldwide.

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Neospora caninum causes neosporosis, a leading cause of bovine abortion worldwide. Uruguay is a developing economy in South America that produces milk to feed seven times its population annually. Naturally, dairy production is paramount to the country's economy, and bovine reproductive failure impacts it profoundly.

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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.

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A cluster of 4 bovine abortions caused by occurred in a dairy herd in Uruguay during a 2-mo period. Case 1 consisted of a placenta from an aborted cow; cases 2-4 were fetuses and their placentas. Grossly, the placenta from one aborted cow had moderate, diffuse reddening of the cotyledons and loss of translucency of the intercotyledonary areas.

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Bovine genital campylobacteriosis (BGC) is a venereal infectious disease that affects reproduction. It is caused by the Gram-negative bacillus subspecies (), which may include the biotype intermedius. The bull is a lifelong asymptomatic carrier and transmitter of the disease.

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Bovine parainfluenza virus-3 (BPIV-3) is a recognized respiratory pathogen of cattle, and it has also been identified in aborted fetuses. However, little is known of this agent as a reproductive pathogen and detailed descriptions of fetal pathology on natural cases are lacking in the scientific literature. This article describes and illustrates lesions in a fetus spontaneously aborted by a first-calving Holstein heifer, naturally infected with BPIV-3 genotype A, broadening the current knowledge on fetal pathology by this virus.

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Article Synopsis
  • Leptospirosis, caused by diverse spirochete bacteria called Leptospira, is a neglected disease affecting both animals and humans, with limited data on its serovars in South America, particularly Uruguay.
  • A 3-year study isolated and characterized 40 strains of Leptospira from infected cattle, identifying five serovars, including L. interrogans and L. borgpetersenii.
  • The findings revealed that about 20% of cattle are shedding pathogenic Leptospira, posing a public health threat, and highlighted the need for improved diagnostics and understanding of the disease's epidemiology in the region.
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Bovine actinobacillosis is typically characterized by pyogranulomatous glossitis (wooden tongue). The involvement of other tissues, generally the skin or lymph nodes, has been regarded as atypical or cutaneous. We describe herein 2 outbreaks of actinobacillosis affecting primarily the lymph nodes of the head and neck.

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Clostridium perfringens type C causes necrotizing enteritis mostly in neonatal animals of several species, including horses. The virulence of C. perfringens type C is mostly mediated by beta toxin (CPB).

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