Toxoplasma gondii in four captive kangaroos (Macropus spp.) in China: Isolation of a strain of a new genotype from an eastern grey kangaroo (Macropus giganteus)

Abstract

Marsupials are highly susceptible to Toxoplasma gondii infection. Here, we report T. gondii infection in four kangaroos from a zoo in China. Kangaroos were imported into China in 2000 and were since bred in zoo. In 2017–2018, four kangaroos died due to respiratory system disease or injury. The bodies were submitted to the laboratory to test for T. gondii infection. Antibodies to T. gondii were found in 75% (3/4) of the kangaroos via the modified agglutination test with the cut-off 1:25. Cysts were observed in the histopathological sections of tongue and diaphragm or squashes of fresh myocardium in two kangaroos. These cysts were confirmed as T. gondii by immunohistochemical staining and molecular biological analysis. One viable T. gondii strain was isolated from one kangaroo and designated as TgRooCHn1. DNA from T. gondii tachyzoites obtained from cell culture was characterized by 10 PCR-RFLP markers and the virulence genes ROP5 and ROP18. The genotype of this isolate did not match with any known genotypes; it was designated as ToxoDB#292. The virulence of TgRooCHn1 (104 tachyzoites) was non-lethal to mice, and it formed tissue cysts. To our knowledge, the present study is the first isolation of ToxoDB#292 strain from kangaroo. Improvemets for captive settings were initiated, including greater attention being paied to birds and stray cats, fed frozen meat for carnivores.

Recent aspects on epidemiology, clinical disease, and genetic diversity of Toxoplasma gondii infections in Australasian marsupials

“…The same scenario appears to be the case for marsupials in China [10]. The animals in the zoo in China were 4-6 years old and had been born in captivity from parents imported in 2000 [10].…”

“…Viable T. gondii (TgRooCHn1) was isolated by bioassay in mice. PCR-RFLP-ToxoDB genotype was #292 [ 10 ] Eastern grey kangaroo ( Macropus giganteus ) Japan Carcass of 1 adult, male kangaroo with neurological signs, anorexia, diarrhea, arrhythmia, was necropsied. Lesions were seen in lungs, brain and heart.…”

“…The animal was MAT-negative but PCR positive. Attempts to isolate T. gondii by bioassay in mice were unsuccessful [ 10 ] Red kangaroo ( Macropus rufus ) USA 1-year-old male with a 1-day history of depression, labored respiration and lethargy. Disseminated toxoplasmosis including fore stomach.…”

“…Ante-mortem diagnosis of toxoplasmosis in marsupials is problematic because they can die suddenly and before developing detectable antibodies. In a study performed in China, out of two marsupials that died of toxoplasmosis, one Macropus giganteus was seropositive whereas one Macropus rufus was seronegative [ 10 ].…”

Isolation and characterization of Toxoplasma gondii from captive caracals (Caracal caracal)

“…They were paraffin sectioned, then sections (5 μm thick) were stained with hematoxylin and eosin (H&E) routinely. Sections suspected for the presence of tissue cysts were stained with immunohistochemistry (IHC) ( Su et al, 2019 ). The primary antibody used was rabbit anti- T. gondii polyclonal antibody.…”