Pathologic and immunohistochemical findings in an outbreak of systemic toxoplasmosis in a mob of red kangaroos

Abstract

Toxoplasma gondii is a zoonotic protozoan pathogen that infects many endothermic vertebrates, including humans; the domestic cat and other felids serve as the definitive host. Macropodids are considered highly susceptible to toxoplasmosis. Here, we describe the clinical, pathologic, and immunohistochemical findings of an outbreak of systemic toxoplasmosis in a mob of 11 red kangaroos ( Macropus rufus), with high morbidity (73%) and mortality (100%) rates. Affected animals had either severe and rapidly deteriorating clinical conditions or sudden death, which was correlated with widespread necrotizing lesions in multiple organs and intralesional T. gondii organisms identified via MIC3-specific immunohistochemistry and confirmed by REP529-specific rtPCR. Quantification of parasites demonstrated the highest parasite density in pulmonary parenchyma compared with other tissues. Our study highlights the continued importance of this severe condition in Australian marsupials.

Acute Disseminated Toxoplasmosis in Two Specimens of Macropus rufogriseus Caused by a Genotype so far Exclusive to South America

“…To our knowledge, this is the first time the parasite load is measured in tissues of infected wallabies. Carossino et al ( 18 ) also performed qPCR but only reported mean CT. Supporting the findings we describe, they demonstrated that the lung was the organ with the highest parasite load, followed by the liver as well.…”

“…Supporting the findings we describe, they demonstrated that the lung was the organ with the highest parasite load, followed by the liver as well. The spleen was not included in real-time PCR ( 18 ).…”

Toxoplasmosis in Captive Ring-Tailed Lemurs (Lemur catta)

“…Nonetheless, some animal species show a higher susceptibility to this parasite and develop fatal toxoplasmosis [ 6 ]. Lemurs, New World non-human primates (NWNHPs), and Australasian marsupials are highly susceptible to toxoplasmosis with frequent sudden death when infected [ 7 , 8 ].…”

Microbial Diversity Profiling of Gut Microbiota of Macropus giganteus Using Three Hypervariable Regions of the Bacterial 16S rRNA

“…Kangaroos commonly occur in regions that are inhabited and used by livestock and humans, and which include surface waters that are used as a drinking water source. As a ruminant animal, the kangaroo has been identified as hosting several human pathogens within their gut microbiota, with the potential to cause zoonotic harm to humans in rare cases [5,6] Due to the diversity of gut microbiota and complex bacterial signatures between animals and humans, microbial source tracking (MST) methods have been developed to identify bacterial taxa that may be novel in order to distinguish animals that contribute to freshwater faecal pollution [7]. As animal faecal contamination is less distinguishable as a point source, identifying the faecal pollution's source once it enters the waterway is difficult [8].…”

“…Kangaroos commonly occur in regions that are inhabited and used by livestock and humans, and which include surface waters that are used as a drinking water source. As a ruminant animal, the kangaroo has been identified as hosting several human pathogens within their gut microbiota, with the potential to cause zoonotic harm to humans in rare cases [ 5 , 6 ]…”