Toxoplasma gondii is the zoonotic parasite responsible for toxoplasmosis in warm-blooded vertebrates. This systematic review compares and evaluates the available knowledge on enzyme-linked immunosorbent assays (ELISAs), their components, and performance in detecting T. gondii antibodies in animals. Four databases were searched for published scientific studies on T. gondii and ELISA, and 57 articles were included. Overall, indirect (95%) and in-house (67%) ELISAs were the most used types of test among the studies examined, but the ‘ID Screen^® Toxoplasmosis Indirect Multi-species’ was common among commercially available tests. Varying diagnostic performance (sensitivity and specificity) and Kappa agreements were observed depending on the type of sample (serum, meat juice, milk), antigen (native, recombinant, chimeric) and antibody-binding reagents used. Combinations of recombinant and chimeric antigens resulted in better performance than native or single recombinant antigens. Protein A/G appeared to be useful in detecting IgG antibodies in a wide range of animal species due to its non-species-specific binding. One study reported cross-reactivity, with Hammondia hammondi and Eimeria spp. This is the first systematic review to descriptively compare ELISAs for the detection of T. gondii antibodies across different animal species.

Toxoplasma gondii is a globally distributed zoonotic protist, capable of infecting all warm-blooded animals. In Australia, cats (Felis catus) are the only definitive host capable of spreading T. gondii infection via oocysts. Free-roaming cats are widespread in Australia and can play a central role in the ecology of T. gondii. Therefore, understanding the epidemiology of this parasite in stray and feral cats is essential to understanding the potential risk of infection in animals and humans. Due to a lack of easily accessible commercial kits, an in-house modified agglutination test (MAT) was established to test for IgG antibodies against T. gondii, using cell culture-derived T. gondii tachyzoites, and compared with a commercial MAT. A total of 552 serum samples collected during 2018 - 2021 from stray (n = 456) and feral cats (n = 90) (samples with missing data n = 6) from four Australian states, representing different age groups of both sexes, were screened for antibodies against T. gondii. Risk factors for T. gondii infection were assessed using multivariable logistic regression analysis. The in-house MAT had excellent agreement with the commercial MAT and provided a reliable and economical serological tool for T. gondii screening in animals. The overall observed seroprevalence for T. gondii in cats was 40.4 % (223/552). Bodyweight (as a proxy for age), geographical location, season and whether cats were feral or stray, were factors associated with T. gondii seropositivity in cats. Sex was not found to be a risk factor for T. gondii infection in feral and stray cats. This study shows that Australian stray and feral cats have a high T. gondii seroprevalence, which may translate to significant health impacts for wildlife species, livestock and the public.

Australian marsupials are particularly susceptible to Toxoplasma gondii, an introduced zoonotic protozoan parasite. Molecular diagnostic methods are a highly specific approach for the detection of parasitic infections such as T. gondii. Importantly, molecular methods are useful for the characterisation of T. gondii to understand the genetic diversity of the parasite. The eastern barred bandicoot (Perameles gunnii) is a small native marsupial species classified as Critically Endangered. Although the species has previously been described as highly susceptible to infection with T. gondii, there is currently no information on the genotypes occurring in this species. This study employed qPCR for the detection of T. gondii in opportunistically obtained tissue samples from eastern barred bandicoot carcasses (n = 113) from Victoria, followed by determination of genotype using a DNA sequence-based virtual restriction fragment length polymorphism (RFLP) method. Overall, 19.5 % of the samples were positive for T. gondii using qPCR. The RFLP analysis revealed the dominance of T. gondii type II while a type II-like genotype was found in two isolates. This is the first study to provide information on prevalent genotypes of T. gondii in eastern barred bandicoots. Epidemiological studies of definitive and intermediate hosts, including further genotyping, are recommended to better understand T. gondii epidemiology for the successful recovery of eastern barred bandicoots in Australia.

The red fox (Vulpes vulpes) is an introduced species to Australia whose population and spatial distribution have grown irreversibly. Due to their opportunistic feeding habits, extensive populations of foxes now inhabit urban and rural environments, where they coexist with humans and domesticated animals. The proximity of these predators presents public and animal health concerns as they harbour diseases that can cross between species. Accordingly, monitoring potential disease risk and prevalence in urban foxes is warranted. This study investigated the occurrence of gastrointestinal parasites in urban and rural foxes around Melbourne, Victoria, Australia. The gastrointestinal tracts of 51 opportunistically collected foxes were thoroughly examined to collect adult helminth (i.e., nematode and cestode) parasites from the stomach as well as from the small and large intestines. The results showed that 92.2 % of foxes were infected with at least one gastrointestinal helminth parasite. Based on a morphological identification of worms, the detected nematode parasites were Toxocara canis (66.7 %) and Uncinaria stenocephala (56.9 %), while the identified tapeworms included Dipylidium caninum (39.2 %), Taenia spp. (11.8 %) and Spirometra mansoni (5.9 %). Single cases of Trichuris vulpis and Physalopetra sp. infections were detected. This study highlights a human and domestic animal health risk, as a crossover of parasitic infections is possible in areas where these parasites coexist.