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Toxoplasmosis in captive Bennett's wallabies (Macropus rufogriseus) in Argentina

Laboratorio de Inmunoparasitología, Cátedra de Parasitología y Enfermedades Parasitarias, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, 60 y 118, (1900) La Plata, Argentina.
Veterinary Parasitology (Impact Factor: 2.55). 04/2007; 144(1-2):157-61. DOI: 10.1016/j.vetpar.2006.09.030
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ABSTRACT Wallabies and other Australian marsupials are among the most susceptible species to Toxoplasma gondii. Fatal generalized toxoplasmosis was diagnosed in two captive 3 year-old female Bennett's wallabies (Macropus rufogriseus) from Argentina (w 1 and w 2) with a history of sudden death. Both animals had internal joeys which died 2 days after their mothers. Serologically, both females and one adult male without clinical signs from the same enclosure (w 3) had antibody titers for T. gondii>or=800 by the modified agglutination test (MAT); another adult male (w 4) was negative (MAT titer<25). Microscopically, tachyzoites were observed associated to non-suppurative meningoencephalitis, hepatitis, myositis, myocarditis and severe enteritis in hematoxylin and eosin stained sections from both w 1 and w 2. Immunohistochemically, parasites in heart, brain and liver sections of both female wallabies reacted with T. gondii antiserum. T. gondii was isolated from brain tissues of w 1 and w 2 by bioassay in mice and by culture in bovine monocytes and both isolates were cryopreserved. Genomic DNA was isolated from tachyzoites grown in cultures derived from both animals. The primer pair B22/B23 specific for T. gondii produced 115bp amplicons on poliacrylamide electrophoretic gels. Stray cats were suspected as the possible source of infection. Not all infected macropods were ill, showing that the infection may be asymptomatic and is not always fatal. A vertical infection could not be proved in the joey from w 2. As far as we know, this is the first confirmed report of toxoplasmosis in Bennet's wallabies in Argentina.

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    • "It is possible that the low levels of diversity in this instance could be attributed to a founder effect, given the isolated nature of this location (Prestrud et al., 2008). Genetic studies of T. gondii in Australia have been particularly limited, though interest in T. gondii in this area has risen due to recent reports of fatal disease in threatened marsupial fauna (Basso et al., 2007; Bermudez et al., 2009; Dubey and Crutchley, 2008; Hartley, 2006; Obendorf et al., 1996). Efforts have accordingly been made to identify parasite genotypes circulating in this area. "
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    • "Serum biochemical abnormalities detected in the sick wallaby, such as hyperproteinaemia, could also indicate an inflammatory process. Increased LDHlevels are often seen in myositis/myocarditis, which have been reported in acute toxoplasmosis in wallabies [5]. Subclinical T. gondii infections, as reported in the other species, have also been documented in macropods [8] [9]. "
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    • "Toxoplasma gondii infection occurs in a broad range of warm blooded animals including humans and is frequently asymptomatic; however, it can be severe or even fatal to some hosts. Some species like New World monkeys (Dietz et al., 1997), lemurs (Spencer et al., 2004), Pallas' cats (Basso et al., 2005), slender-tailed meerkats (Basso et al., 2009) and some Australian marsupials (Basso et al., 2007; Dubey et al., 1988) are considered highly susceptible to clinical toxoplasmosis, but little is known about T. gondii genotypes affecting these species. In the last years several fatal cases in macropods, principally wallabies, were reported (Adkesson et al., 2007; Basso et al., 2007; Bermudez et al., 2009; Dubey and Crutchley, 2008). "
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