SARCOCYSTIS AND OTHER PARASITES IN FECES OF BOBCATS (LYNX RUFUS) FROM MISSISSIPPI.

Rectal contents of 56 adult bobcats (Lynx rufus) in 2014 and 2017 from remote areas of Mississippi were examined microscopically for parasite stages after the sugar flotation method. Among the helminths, eggs/larvae found were: Paragonimus sp. in 12, Toxocara cati-like in 16, trichurid-capillarid-like in 3, hookworms in 27, and lungworms in 28. Among the protozoa, oocysts/cysts found were: Cystoisospora felis-like in 2, Cystoisospora rivolta-like in 4, Cryptosporidium sp. in 1, and Giardia sp. in 1. Additionally, numerous Sarcocystis sporocysts were detected in the feces of 12 bobcats; sporocysts were described morphologically. The status of C. felis derived from the bobcat and other wild felids is reviewed and compared with C. felis from the domestic cat. It is the first record of C. rivolta from the bobcat. The presence of eggs of Paragonimus sp. and T. cati in feces of 21.4% and 28.5%, respectively, suggests a role for the bobcat in the dissemination of these zoonotic helminths in the environment in the wild. Taxonomy of coccidia of wild Felidae is discussed and Isospora lyncisLevine and Ivens, 1981 from the Lynx is now regarded as a species inquirenda.

Fatal infection with Versteria sp. in a muskrat, with implications for human health.

The Taeniidae tapeworms are a family of helminths that have a similar life cycle, with intermediate hosts developing characteristic cysts in visceral organs. We describe here a case in Pennsylvania, USA, of fatal Versteria infection in a muskrat (Ondatra zibethicus), which, to our knowledge, has not been reported to develop disease associated with infection. Postmortem examination revealed widespread tissue loss and replacement by solid-bodied cestode larvae with minimal adjacent inflammation in many visceral organs, most severe in the lungs, liver, and brain. Key morphologic features via histology included cephalic structures and short rostellar hooklets, which are characteristic for the genus. Genetic characterization confirmed the cestode as being an undescribed lineage of Versteria that has been implicated as the cause of severe morbidity and mortality in humans and nonhuman primates in North America. Considering the zoonotic significance of this pathogen, our report expands on the limited literature regarding disease caused by Versteria and emphasizes the need to identify the causative tapeworm more accurately, especially in rodent intermediate hosts given that previous reports do not have molecular confirmation of species.

Surveillance for diseases, pathogens, and toxicants of muskrat (Ondatra zibethicus) in Pennsylvania and surrounding regions.

Using diagnostic data and contemporary sampling efforts, we conducted surveillance for a diversity of pathogens, toxicants, and diseases of muskrats (Ondatra zibethicus). Between 1977 and 2019, 26 diagnostic cases were examined from Kansas and throughout the Southeast and Mid-Atlantic, USA. We identified multiple causes of mortality in muskrats, but trauma (8/26), Tyzzer's disease (5/6), and cysticercosis (5/26) were the most common. We also conducted necropsies, during November 2018-January 2019 Pennsylvania muskrat trapping season, on 380 trapper-harvested muskrat carcasses after the pelt was removed. Tissue samples and exudate were tested for presence of or exposure to a suite of pathogens and contaminants. Gastrointestinal tracts were examined for helminths. Intestinal helminths were present in 39.2% of necropsied muskrats, with Hymenolepis spp. (62%) and echinostome spp. (44%) being the most common Molecular testing identified a low prevalence of infection with Clostridium piliforme in the feces and Sarcocystis spp. in the heart. We detected a low seroprevalence to Toxoplasma gondii (1/380). No muskrats were positive for Francisella tularensis or Babesia spp. Cysticercosis was detected in 20% (5/26) of diagnostic cases and 15% (57/380) of our trapper-harvested muskrats. Toxic concentrations of arsenic, cadmium, lead, or mercury were not detected in tested liver samples. Copper, molybdenum, and zinc concentrations were detected at acceptable levels comparative to previous studies. Parasite intensity and abundance were typical of historic reports; however, younger muskrats had higher intensity of infection than older muskrats which is contradictory to what has been previously reported. A diversity of pathogens and contaminants have been reported from muskrats, but the associated disease impacts are poorly understood. Our data are consistent with historic reports and highlight the wide range of parasites, pathogens and contaminants harbored by muskrats in Pennsylvania. The data collected are a critical component in assessing overall muskrat health and serve as a basis for understanding the impacts of disease on recent muskrat population declines.

A Review of Pathogens, Diseases, and Contaminants of Muskrats (Ondatra zibethicus) in North America.

Over the last 50 years, significant muskrat (Ondatra zibethicus) harvest declines have been observed throughout North America. Several theories for the decline have been proposed, including increased parasite infections and disease within muskrat populations. No existing wholistic review of muskrat exposure to pathogens, contaminants, and diseases exists. To address this knowledge gap, we conducted a thorough review of existing literature on muskrat pathogens, contaminants, and diseases across their natural range. This review is comprised of 131 articles from 1915 to 2019 and from 27 U.S. states and 9 Canadian provinces. A wide diversity of contaminants, toxins, and pathogens were reported in muskrats, with the most common diseases being cysticercosis, tularemia, Tyzzer's disease, and biotoxin poisoning from cyanobacteria. This review provides a summary of muskrat pathogens, contaminants, and diseases over a century that has observed significant population declines throughout the species' range in North America. Such data provide a baseline for understanding the potential role of disease in these declines. In addition, these data highlight critical knowledge gaps that warrant future research efforts.

Bobcats (Lynx rufus) are natural definitive host of Besnoitia darlingi.

Bovine besnoitiosis, caused by Besnoitia besnoiti, is an economically important disease of cattle in many countries but its transmission remains a mystery. Wild felids are suspected to be its definitive hosts. The domestic cat (Felis catus) is known experimental definitive host for Besnoitia species of rodents. Here, we report for Besnoitia darlingi the first identification of a natural definitive host, the bobcat (Lynx rufus). Oocysts resembling Toxoplasma gondii (unsporulated; 10.9±0.8×12.1±0.2µm; n=5) were detected microscopically in the feces of two of 25 free ranging wild bobcats from Mississippi, USA. After detailed investigation, we identified these oocysts as B. darlingi and not T. gondii. The IFN-γ gene knockout (KO) mice fed oocysts from bobcats died of acute besnoitiosis and tachyzoites were found in their tissues. Oocysts were also mildly pathogenic to outbred Swiss Webster mice (SW) (Mus musculus). The SW mice fed oocysts became ill but generally survived and developed characteristic thick-walled Besnoitia tissue cysts in their tongue and heart muscles and brains. Two laboratory-raised domestic cats (Felis catus) excreted B. darlingi oocysts after ingesting murine tissues infected with bobcat-derived oocysts. The parasite was successfully cultivated in African green monkey kidney fibroblast cells (CV-1 cell line) seeded with infected murine tissue homogenate. The multilocus PCR-DNA sequencing (18S rDNA, 28S rDNA, and ITS-1) from culture-derived tachyzoites confirmed the parasite as B. darlingi. Our results suggest that bobcats may be an important link in the sylvatic cycle of Besnoitia species and bioassay or molecular tests are needed to differentiate Toxoplasma gondii-like oocysts in feces of felids, both domestic and wild cats.