Clostridium spiroforme-associated enteric disease in domestic rabbits: a retrospective study of 32 cases in California, 1992-2019, and literature review.

Clostridium spiroforme has been associated with spontaneous and antibiotic-associated enteric disease (C. spiroforme-associated enteric disease, CSAED) in rabbits, which is clinically characterized by anorexia, diarrhea, or sudden death. Diagnosis is usually based on gross and microscopic lesions, coupled with finding the characteristic coiled bacteria in intestinal smears. Isolation of C. spiroforme is often challenging, and a PCR protocol has been developed. We reviewed 32 cases of CSAED submitted for autopsy to the Davis, Tulare, and Turlock laboratories of CAHFS between 1992 and 2019. The reported gross findings were soiling of the perineum, tail, and/or hind legs with diarrhea (16 of 32); gastric (16 of 32), small intestinal (6 of 32), cecal (15 of 32), and/or colonic (4 of 32) distention with brown-to-green, watery content; and serosal hemorrhages in the cecum (15 of 32). The most common microscopic finding was necrotizing enteritis (19 of 32), followed by cecal mucosal or submucosal edema (8 of 32), necrotizing or pleocellular typhlitis (6 of 32), necrotizing or heterophilic typhlocolitis (6 of 32), and cecal transmural hemorrhages (5 of 32). In all 32 rabbits, typical helically coiled, gram-positive bacilli were observed in fecal or intestinal smears. C. spiroforme was isolated from the intestinal content of 2 of 24 rabbits and detected by PCR assay in 8 of 8 rabbits.

A polyomavirus detected in American black bear (Ursus americanus).

Polyomaviruses are ancient DNA viruses that infect several species of animals. While recognition of the family Polyomaviridae has grown rapidly, there are few studies that consider their potential association with disease. Carnivora are a diverse and widespread order affected by polyomaviruses (PyVs) that have co-evolved with their hosts for millions of years. PyVs have been identified in sea lions, raccoons, badgers, Weddell seals, and dogs. We have discovered a polyomavirus, tentatively named "Ursus americanus polyomavirus 1" (UaPyV1) in black bears (Ursus americanus). UaPyV1 was detectable in various tissues of six out of seven bears submitted for necropsy. Based on viral phylogenetic clustering and detection of the virus in multiple individuals, we suggest that black bears are the natural hosts for UaPyV1. In this albeit small group, there is no clear relationship between UaPyV1 infection and any specific disease.

Demodectic mange in threatened southern sea otters (Enhydra lutris nereis).

BACKGROUND: Southern sea otters (Enhydra lutris nereis) rely on intact pelage for thermoregulation, and thus clinically significant demodicosis and associated alopecia can cause morbidity and death. HYPOTHESIS/OBJECTIVES: This study aimed to describe lesions associated with follicular Demodex sp. infestation, estimate the prevalence and intensity of infestation, describe mite distribution across key anatomical regions, and assess mite presence or absence in relation to lesions and host risk factors. ANIMALS: Twenty necropsied, wild southern sea otters that stranded along the central California coast from 2005 to 2018. METHODS AND MATERIALS: Grossly normal and abnormal integument from the head, perineum, genitals, mamillary papillae and limbs was assessed microscopically for mites and mite-associated pathological findings. RESULTS: Intrafollicular mites were observed in the integument of 55% of otters and 20% had clinical demodicosis. Demodicosis was considered to be contributory to death or euthanasia in two cases. Although Demodex sp. mites often were observed microscopically in grossly normal skin, the presence of multiple densely-packed intrafollicular mites generally was associated with pigmentary incontinence, ectatic follicles, lymphoplasmacytic perifolliculitis, and neutrophilic and lymphoplasmacytic, dermal inflammation. Other findings included epidermal hyperplasia, orthokeratotic hyperkeratosis of epidermis and follicular epithelium, concurrent pyoderma and cell necrosis. Perioral integument, especially of the chin, had the highest prevalence of mites and the highest mite density, suggesting facial contact as a means of mite transmission. CONCLUSIONS AND CLINICAL IMPORTANCE: Our research confirmed demodectic mange as a contributor to morbidity and mortality in sea otters, with important implications for clinical care, rehabilitation and conservation.

Fatal Photobacterium damselae-induced enteritis in a leatherback turtle Dermochelys coriacea.

Stranded leatherback turtle Dermochelys coriacea complete pathology reports are rare, and the cause of mortality is difficult to determine in many cases. We conducted a complete pathological study of a stranded leatherback turtle from the western Mediterranean. The main finding was a fibrino-necrotizing enteritis with associated bacteria which were identified as Photobacterium damselae subsp. damselae according to biochemical and phenotypical characteristics. This report provides evidence of the pathogenic effect of this bacterium in wild sea turtles.

The physiological cost of male-biased parasitism in a nearly monomorphic mammal.

BACKGROUND: Even though male-biased parasitism is common in mammals, little effort has been made to evaluate whether higher parasitic burden in males results in an extra biological cost, and thus a decrease in fitness. Body condition impairment and the augmentation of oxidative stress can be used as indicators of the cost of parasite infections. Here, we examined relationships between gastrointestinal and respiratory helminths, body condition and oxidative stress markers (glutathione peroxidase, paraoxonase-1) in 28 Pyrenean chamois (Rupicapra p. pyrenaica) sampled in autumn. RESULTS: Only male chamois showed a reduction in body condition and higher oxidative stress due to parasite infection, likely because of the extremely high parasite burdens observed in males. CONCLUSIONS: This study made evident a disparity in the physiological cost of multiple parasitism between sexes in a wild mammal, mainly due to parasitic richness. Because of the similar life expectancy in male and female chamois, we suggest that males may have developed natural mechanisms to compensate for higher parasite loads during the rut.