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: 2.46). 04/2007; 144(1-2):157-61. DOI: 10.1016/j.vetpar.2006.09.030
Source: PubMed


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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    ABSTRACT: Toxoplasma gondii, a zoonotic protozoal parasite, is well-known for its global distribution and its ability to infect virtually all warm-blooded vertebrates. Nonetheless, attempts to describe the population structure of T. gondii have been primarily limited to samples isolated from humans and domesticated animals. More recent studies, however, have made efforts to characterize T. gondii isolates from a wider range of host species and geographic locales. These findings have dramatically changed our perception of the extent of genetic diversity in T. gondii and the relative roles of sexual recombination and clonal propagation in the parasite's lifecycle. In particular, identification of novel, disease-causing T. gondii strains in wildlife has raised concerns from both a conservation and public health perspective as to whether distinct domestic and sylvatic parasite gene pools exist. If so, overlap of these cycles may represent regions of high probability of disease emergence. Here, we attempt to answer these key questions by reviewing recent studies of T. gondii infections in wildlife, highlighting those which have advanced our understanding of the genetic diversity and population biology of this important zoonotic pathogen.
    Veterinary Parasitology 07/2011; 182(1):96-111. DOI:10.1016/j.vetpar.2011.07.018 · 2.46 Impact Factor
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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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    ABSTRACT: A red-necked male wallaby (Macropus rufogriseus) from a German zoo was presented for acute onset of severe neurological signs, including head tremor, lethargy, unresponsiveness, and weakness. Serum biochemical abnormalities included increased LDH- and AST-levels, hyperproteinaemia, and reduced ALT-, ALP-, and creatinine-levels. The wallaby was found serologically positive for Toxoplasma gondii by the indirect haemagglutination test. After initiation of therapy by subcutaneous injections of trimethoprim/sulfadoxin, amelioration of neurological signs was noted and after 10 days the affected wallaby recovered. T. gondii can be confirmed rapidly by serology, and immediate therapy may reduce clinical illness and fatality of the disease within captive macropods.
    Veterinary Medicine International 06/2010; 2010:561212. DOI:10.4061/2010/561212
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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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    ABSTRACT: Toxoplasma gondii infection is frequently asymptomatic; however, it can be severe or even fatal to some hosts. In this study, diagnosis of disseminated toxoplasmosis in one red kangaroo (Macropus rufus) and one great grey kangaroo (Macropus giganteus) from the La Plata Zoo, Argentina and the isolation and molecular characterization of T. gondii are reported. Both male kangaroos showed depression and sudden death. Toxoplasma gondii infection was diagnosed by fresh examination, histopathology, immunohistochemistry, PCR and bioassay in mice. During fresh examination many protozoan cysts were observed in diaphragm, heart and hind limb muscles of M. rufus. Cysts were also observed in samples from M. giganteus, although in lower number. Cysts from both kangaroos stained strongly with T. gondii anti-serum by immunohistochemistry. The M. rufus showed more considerable histopathological lesions like non-suppurative meningoencephalitis, myositis and myocarditis. All mice inoculated with tissues from both kangaroos developed IFAT titers to T. gondii (titer >or=800) and brain cysts at necropsy. Both T. gondii isolates were maintained by mice passages and the M. rufus isolate was also maintained in cell culture. Toxoplasma gondii DNA from tissue samples was analyzed by PCR-RFLP analysis using the markers 5'SAG2, 3'SAG2, BTUB, GRA6, SAG3, c22-8, L358, PK1, c29-2 and Apico. Genotyping revealed that the T. gondii isolate from M. rufus was clonal type III and the isolate from M. giganteus was clonal type II. This is the first report of disseminated toxoplasmosis in M. rufus and M. giganteus in Argentina caused by genotypes of T. gondii considered non-virulent in a mouse model.
    Veterinary Parasitology 04/2010; 169(1-2):57-61. DOI:10.1016/j.vetpar.2009.12.004 · 2.46 Impact Factor
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