Toxoplasmosis epidemic in a population of urbanised allied rock-wallabies (Petrogale assimilis) on Magnetic Island (Yunbenun), North Queensland.

A mortality event involving 23 allied rock-wallabies (Petrogale assimilis) displaying neurological signs and sudden death occurred in late April to May 2021 in a suburban residential area directly adjacent to Magnetic Island National Park, on Magnetic Island (Yunbenun), North Queensland, Australia. Three allied rock-wallabies were submitted for necropsy, and in all three cases, the cause of death was disseminated toxoplasmosis. This mortality event was unusual because only a small, localised population of native wallabies inhabiting a periurban area on a tropical island in the Great Barrier Reef World Heritage Area were affected. A disease investigation determined the outbreak was likely linked to the presence of free-ranging feral and domesticated cats inhabiting the area. There were no significant deaths of other wallabies or wildlife in the same or other parts of Magnetic Island (Yunbenun) at the time of the outbreak. This is the first reported case of toxoplasmosis in allied rock-wallabies (Petrogale assimilis), and this investigation highlights the importance of protecting native wildlife species from an infectious and potentially fatal parasitic disease.

Infection with Toxoplasma gondii in a red kangaroo (Macropus rufus) and a Patagonian mara (Dolichotis patagonum) in captivity / Infecção por Toxoplasma gondii em um canguru vermelho (Macropus rufus) e em uma mara (Dolichotis patagonum) em cativeiro

Abstract Toxoplasmosis is an infectious, zoonotic and parasitic disease, caused by Toxoplasma gondii. In this manucript, two cases of infection with T. gondii in captive animals from a zoological park in the central region of Chile are described. One case was a red kangaroo (Macropus rufus), which is highly susceptible to the infection, and the other was a Patagonian mara (Dolichotis patagonum), a rodent in which there is no previous report of the infection. Both animals had myocarditis, with the presence of intralesional tachizoites and cysts suggestive of infection with T. gondii. This infection was confirmed by immunohistochemistry in both animals. The origin of the infection is unknown, but it is likely that free ranging domestic felines were associated with the dissemination of the parasites. This highlights the importance of controlling the domestic animal populations in zoological parks. To the best of our knowledge, this is the first time that T. gondii infection is described in a Patagonian mara, adding a new host for this infectious agent.

Resumo Toxoplasmose é uma doença parasitária infecciosa e zoonótica causada por Toxoplasma gondii. São descritos dois animais com toxoplasmose, mantidos em cativeiro, em um zoológico na região central do Chile. Um destes foi um canguru vermelho (Macropus rufus), o qual é altamente suscetível à infecção; o outro foi uma mara (Dolichotis patagonum), um roedor sem relato prévio de infecção por T. gondii. Ambos os animais tinham miocardite associada a organismos protozoários intralesionais, sugestivos de infecção por Toxoplasma gondii. Esta infecção foi confirmada pela imuno-histoquímica, nos dois animais. A origem da infecção é desconhecida, mas é provável que felinos domésticos errantes estejam associados com a disseminação do protozoário. Isso destaca a importância do controle populacional de animais domésticos em zoológicos. Até onde se sabe, esta é a primeira vez que a infecção por T. gondii é descrita em uma mara, adicionando um novo hospedeiro para este agente infeccioso.

Toxoplasmosis sistémica en un canguro rojo (Macropus rufus) cautivo / Systemic toxoplamosis in a captive red kangaroo (Macropus rufus)

Los objetivos del estudio fueron presentar y documentar los hallazgos histopatológicos de toxoplasmosis sistémica en un canguro rojo (Macropus rufus) mantenido en cautiverio donde se describen los hallazgos macro y microscópicos encontrados y los análisis adicionales realizados. En el laboratorio de histopatología animal (Universidad de los Llanos) se recibieron muestras de tejidos fijados en formol tamponado, al 10% que procedían de un ejemplar macho de Macropus rufus, de ocho años de edad y 50 kg de peso corporal. Las muestras se procesaron mediante métodos rutinarios para microscopía óptica. Los cortes histológicos de 3-4 mm de grosor se colorearon con Hematoxilina-Eosina (H&E) y se realizó en algunos cortes la tinción de Ácido Periódico Schiff (PAS), PCR e IHQ. Al análisis histopatológico se encontró una toxoplasmosis sistémica asociada a quistes de protozoarios con inmunoreactividad positiva para T. gondii. La detección de T gondii en tejidos en formalina fue hecha usando dos ensayos de PCR que señalaban segmentos de ADN de diferentes secuencias repetitivas encontradas en T gondii y la IHQ confirmo lo hallado por PCR. Histopatológicamente se diagnosticó infección crónica por protozoarios eucoccideos de la familia Sarcocystidae. El diagnóstico etiológico fue de toxoplasmosis.

The objetives of this study were to present and document the hystopathologycal findings of systemic toxoplamosis in a captive red kangaroo (Macropus rufus) which described macro and microscopic findings of the hystopathological analysis. In the laboratory of animal histopathology (Universidad de los Llanos) formalin fixed tissue specimens were received, from a captive male Macropus rufus, who was eight years old and weighed 50 kg. The samples were processed by usual methods for optical microscopy. The histological sections of 3-4 mm thick were colored with Hematoxilin-Eosin (H&E) and then some samples stained with Periodic Acid Schiff (PAS), and processed by PCR and IHQ. Once the histopathological analysis was performed systemic toxoplasmosis was associated to protozoa cysts immunoreactives to T. gondii. The molecular detection of T. gondii in formalin fixed tissues was made using two PCR tests and confirmated by IHQ. Histopathologically a chronic infection by an eucoccideo protozoa from the Sarcocystidae family was diagnosed. The etiologic diagnosis was toxoplasmosis.