Fatal Toxoplasmosis and Enteroepithelial Stages of Toxoplasma gondii in a Pallas Cat (Felis manul)¹

Abstract

Toxoplasma gondii was found in tissues of a six-year-old female Pallas cat (Felis manul) from the Milwaukee County Zoo. Toxoplasma gondii meronts (types D and E), gamonts, and oocysts were present in the epithelium of the small intestine. Numerous unsporulated oocysts were present in the intestinal lumen. The cat died of acute, overwhelming toxoplasmosis. Necrotic enteritis, multifocal necrotizing granulomatous hepatitis, and pneumonia were the prominent lesions.

Exploring the Ecologic Basis for Extreme Susceptibility of Pallas' Cats (Otocolobus Manul) to Fatal Toxoplasmosis

“…Furthermore, PCR analysis of brain tissue obtained from 45 prey animals failed to identify T. gondii in any animal tested. In contrast, studies in other geographic regions have reported T. gondii seroprevalence ranging from 9% to 85% in nondomestic cat species, from 33.7% to 80% in domestic cats, and from 2.1% to 24% in prey species (Roelke et al, 1993;Dubey et al, 1995;Hejlicek and Nezval, 1997;Hill et al, 1998;Silva et al, 2001;Defeo et al, 2002). Further research is warranted to substantiate our findings.…”

“…In their culture, Mongolians typically do not maintain domestic cats as companion animals, limiting the number of feral cats available to serve as definitive hosts for T. gondii. Persistence of T. gondii is dependent on the presence of felids in the environment (Wallace, 1969), and low domestic cat densities are associated with low T. gondii prevalence (Dubey et al, 1997). Furthermore, the severity of the winters and high altitude likely reduce the viability of any T. gondii oocysts that may be shed into the environment by domestic cats and other wild felids in Mongolia.…”

“…Furthermore, the severity of the winters and high altitude likely reduce the viability of any T. gondii oocysts that may be shed into the environment by domestic cats and other wild felids in Mongolia. The T. gondii oocysts have poor survivorship at both extreme temperatures and high altitudes (Dubey and Beattie, 1988). The combination of limited numbers of definitive hosts and low oocyst survival during the winter months could impair the ability of T. gondii to complete its natural life cycle and persist in the wild.…”

“…In the majority of deceased kittens evaluated at necropsy, infection with Toxoplasma gondii was identified as the cause of death (Swanson, 1999;Kenny et al, 2002). Almost all adult Pallas' cats (Ͼ80%) in North American zoos are chronically seropositive for anti-T. gondii immunoglobulins (Swanson, 1999) and, like most adult felids, only rarely have clinical signs of infection (Reimann et al, 1974;Dubey et al, 1988;Kenny et al, 2002). During pregnancy, however, maternal immune responses in seropositive females apparently are not protective in Pallas' cats, unlike the case in pregnant domestic cats and other cat species with previous exposure to T. gondii (Swanson, 1999;Kenny et al, 2002).…”

DETECTION OF SEASONAL WEIGHT LOSS AND A SEROLOGIC SURVEY OF POTENTIAL PATHOGENS IN WILD PALLAS' CATS (FELIS[OTOCOLOBUS]MANUL) OF THE DAURIAN STEPPE, RUSSIA

“…Spatial and social organization of this species in the wild is poorly known (Kirilyuk and Puzanskii 2000;Ross 2009). Captive breeding of Pallas' cats has been successful; however, there are no persistent captive populations because kitten survival is low (,40%;Swanson 1999;Kenny et al 2002) because of susceptibility to Toxoplasma gondii (Dubey et al 1988;Basso et al 2005). Brown et al (2002) showed that prevalence of antibodies to T. gondii was 13% in wild cats in Mongolia, but 100% in cats in captivity.…”