Abstracts: Animals are key to human toxoplasmosis

Toxoplasma gondii is an extremely successful protozoal parasite which infects almost all mammalian species including humans. Approximately 30 per cent of the human population worldwide is chronically infected with T gondii. In general, human infection is asymptomatic but the parasite may induce severe disease in fetuses and immunocompromised patients. In addition, T gondii may cause sight-threatening . . . → Read More: Abstracts: Animals are key to human toxoplasmosis

Vets and doctors warned of potential epidemic


Jacqui Norris with Richard Malik, Tanya Sorrell, Ed Breitschwerdt and Michael Ward at the 2014 Zoonoses conference

Jacqui Norris with Richard Malik, Tanya Sorrell, Ed Breitschwerdt and Michael Ward at the 2014 Zoonoses conference

Bartonella could be responsible for a hidden epidemic of disease in animals and humans, according to a US veterinary infectious disease expert.

Edward Breitschwerdt, from the Centre for Comparative Medicine and Translational Research at North Carolina State University College of Veterinary Medicine, updated doctors and veterinarians at the Australasian Society for Infectious Diseases Zoonoses conference in Brisbane last month.

He warned that Bartonella species, a group of Gram negative rods, represented an occupational hazard for veterinarians in particular, with exposure possible via many routes including insect vectors, scratches and bites, needle-stick injury and potentially inhalation of flea faeces. Phylogenetically, the disease is closely related to Brucella species and can cause similar chronic, relapsing disease manifestations that are challenging to diagnose and often refractory to treatment.

Breitschwerdt said bartonellosis Continue reading Vets and doctors warned of potential epidemic

Transmissible cancers in dogs and Tasmanian devils

Figure 1.

The Tasmanian devil, the world’s largest marsupial carnivore, is facing possible extinction in the wild due to a transmissible facial cancer known as Tasmanian devil facial tumour disease (DFTD) (Figure 1). DFTD is spread when living cancer cells are spread between animals by biting. In DFTD, the living cancer cell itself is the infectious agent of disease and it remains unclear why these cancer cells are not detected and rejected by the devil’s immune system. The distressing plight of the Tasmanian devil has drawn attention to the existence of transmissible cancers, parasitic cancers spread by the transfer of living cancer cells between hosts. However, it remains a surprisingly little-known fact that the only other transmissible cancer that bears any resemblance to DFTD is a dog cancer that is right under our noses here in Australia.

Canine transmissible venereal tumour (CTVT) is one of the world’s most remarkable cancers. It is a transmissible cancer that affects dogs worldwide. Usually spread during coitus, the disease is most prevalent in areas with large numbers of free-roaming sexually active dogs. The tumour affects both male and female animals, and appears to affect dogs of any breed. CTVT generally manifests itself in the appearance of tumours in and around the genital area, often at the base of the penis in males and in the vulva of females. Starting as small shiny pink/grey lesions, the tumours can progress to become very large and multi-lobulated (Figure 2). The tumour may aggressively invade surrounding tissues and become ulcerated and secondarily infected. However, a combination of surgical debulking and chemotherapy (using vincristine) is often curative.

Figure 2

Genetic studies have provided strong evidence that CTVT is in fact one living cancer cell line that has spread worldwide with dogs. Thus all CTVT tumours are derived from a single original tumour that arose once and has been transmitted through the dog population as a clone. The tumour itself bears closest genetic resemblance to wolves, suggesting that this tumour may have first arisen in a wolf before hitch-hiking its way into dogs through sexual contact. Genetic evidence suggests that the tumour may in fact be quite old, and that the original wolf that gave rise to the tumour may have even lived thousands of years ago. CTVT is by far the oldest known continuously growing cancer in the world. Continue reading Transmissible cancers in dogs and Tasmanian devils