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Ranaviruses are the second deadliest pathogens for amphibian populations throughout the world. Despite their wide distribution in America, these viruses have never been reported in Mexico, the country with the fifth highest amphibian diversity in the world. This paper is the first to address an outbreak of ranavirus in captive American bullfrogs (Lithobates catesbeianus) from Sinaloa, Mexico. The farm experienced high mortality in an undetermined number of juveniles and sub-adult bullfrogs. Affected animals displayed clinical signs and gross lesions such as lethargy, edema, skin ulcers, and hemorrhages consistent with ranavirus infection. The main microscopic lesions included mild renal tubular necrosis and moderate congestion in several organs. Immunohistochemical analyses revealed scant infected hepatocytes and renal tubular epithelial cells. Phylogenetic analysis of five partial ranavirus genes showed that the causative agent clustered within the Frog virus 3 clade. Risk assessment with the Pandora+ protocol demonstrated a high risk for the pathogen to affect amphibians from neighboring regions (overall Pandora risk score: 0.619). Given the risk of American bullfrogs escaping and spreading the disease to wild amphibians, efforts should focus on implementing effective containment strategies and surveillance programs for ranavirus at facilities undertaking intensive farming of amphibians.

In the four years following the first detection of ranavirus (genus Ranavirus, family Iridoviridae) infection in Dutch wildlife in 2010, amphibian mortality events were investigated nationwide to detect, characterize and map ranaviruses in amphibians over time, and to establish the affected host species and the clinico-pathological presentation of the disease in these hosts. The ultimate goal was to obtain more insight into ranavirus disease emergence and ecological risk. In total 155 dead amphibians from 52 sites were submitted between 2011 and 2014, and examined using histopathology, immunohistochemistry, virus isolation and molecular genetic characterization. Ranavirus-associated amphibian mortality events occurred at 18 sites (35%), initially only in proximity of the 2010 index site. Specimens belonging to approximately half of the native amphibian species were infected, including the threatened Pelobates fuscus (spadefoot toad). Clustered massive outbreaks involving dead adult specimens and ranavirus genomic identity indicated that one common midwife toad virus (CMTV)-like ranavirus strain is emerging in provinces in the north of the Netherlands. Modelling based on the spatiotemporal pattern of spread showed a high probability that this emerging virus will continue to be detected at new sites (the discrete reproductive power of this outbreak is 0.35). Phylogenetically distinct CMTV-like ranaviruses were found in the south of the Netherlands more recently. In addition to showing that CMTV-like ranaviruses threaten wild amphibian populations not only in Spain but also in the Netherlands, the current spread and risk of establishment reiterate that understanding the underlying causes of CMTV-like ranavirus emergence requires international attention.

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Toxoplasmosis is a disease of worldwide distribution that parasites the intestinal tract of wild and domestic cats. However, in New World monkeys it is considered an acute and fatal illness. The reason for its high susceptibiliy in this particular species is still unknown, but it has been theorized that their habitat and living conditions, in high trees, might be a important factor. Necropsy was performed on 5 squirrel monkeys (Saimiri sciureus), three males (adult) and two female (one of them gravid), with a clinical history of eye redenning and presence of bloody serous foam in the nostrils. Gros examination of the lung showed non collapsed lobes, dark red parenchyma and irregular pale pink nodular areas. A five animals showed apparent hepatomegaly. Histological findings revealed an interstitial pneumonia with a prominent thickening of alveolar septae, and numerous foamy macrophages with intracytoplasmic basophilic structures 20- 2 µm long, covered by a refringent wall and housing PAS positive basophilic structures that were aproximately 8 µm lon (bradyzoites), which were identified as protozoal cysts. The liver showed multiple foci of periportal inflammatory cell and numerous parasitic cysts that were also observed in spleen and brain tissue. Inmunohistochemical technique was performed on selected samples of brain, liver and lung tissue, which resulted positive for Toxoplasma gondii using antibodies of hyperimmune antiserum-caprine 6244 origin, in a 1:300 dilution. Samples of the same tissues were processed for transmission electron microscopy. Hepatocytes of the liver showed multiple intracytoplasmic vacuoles with parasitic structures consistent with tachyzoites, which were 3.6 µm long and measured 2.3 µm in diameter. The possesed a slightly wavy electrodense plasmatic membrane that exhibited a conoid in its anterior end, along with several electrodense micronemes. Ultraestructural features like the conoid and the location of micronemes allowed us to identify the parasite as Toxoplasma gondii. Clinical history, necropsy findings, microscopic examination, inmunohistochemica analysis and electron microscopy of all five squirrel monkeys were consistent with a diagnosis of systemic toxoplasmosis This report shows the high suceptibiliity of New World monkeys to become infected with this parasite. Therefore toxoplasmosis should be considered among the differential diagnosis for diseases with non specific clinical signs in this particular species. [ABSTRACT FROM AUTHOR]