University Of São Paulo Collaboratively Developed Animation Assists In Understanding Toxoplasmosis

Unknown to most of the population, infection by the protozoan Toxoplasma gondii (toxoplasmosis) is a significant public health problem. To disseminate information about the disease, researchers created a didactic animation that explains how the parasite reproduces. Professor Hilda Fátima de Jesus Pena, from the Faculty of Veterinary Medicine and Zootechnics (FMVZ) at USP, participated in the project in partnership with the Moredun Research Institute , from Scotland.

The video was developed by the animation studio Ping Creates, led by Selina Wagner, as part of the project funded by the São Paulo Research Foundation (Fapesp), the UK Research and Innovation and the Moredun Foundation. The initiative proposes to investigate differences in the virulence of Toxoplasma gondii variants and how they act in the organism, in order to promote greater community health, food safety and toxoplasmosis control. The video was made available in English and Portuguese. “We contributed ideas and the translation of the narration. The video is an incredible educational tool for all audiences because it is clear, light and very informative”, says the professor to Jornal da USP .

Toxoplasma gondii is one of the most successful parasite infections worldwide. In August 2018, the outbreak of the disease in the city of Santa Maria, in Rio Grande do Sul, registered 647 confirmed cases and was considered the largest in the world. According to the World Health Organization (WHO), it is estimated that about half of the world’s population has already been infected.

Despite the high incidence of cases, the disease is still unknown to a large part of the population and lacks public policies to raise awareness and fight the zoonosis. “In Brazil, most actions involving toxoplasmosis take place in public universities”, says Hilda. She highlights the lack of actions involving the prevention of the disease in pregnant people, who are the most vulnerable to infection.


Toxoplasma gondii infection
Infection occurs when the host ingests contaminated food for the first time, which takes the protozoan to the stomach, where it rapidly reproduces. The parasite can bypass the intestinal cells and invade other body units, which allows its expansion to other body tissues. In response to infection, the immune system envelops the protozoa in cysts, which can remain in different host tissues for the rest of its life. “The cysts form pockets that surround the protozoan, reducing the multiplication of the parasite in the organism”, explains Hilda.


Toxoplasmosis is a silent disease
The ingestion of poorly prepared meat from animals with these cysts present in the organism, as well as contaminated vegetables and water, is the main way of infection of the protozoan in humans. In healthy immune systems, the parasite does not cause symptoms in the host in most cases. People who are immunosuppressed, pregnant or living with the HIV virus and patients undergoing chemotherapy or immunosuppressive drugs for organ transplantation are the most likely to present more severe symptoms of the disease, which include fever, headache, mental confusion, lack of coordination and seizures. In the case of pregnant people, there is congenital transmission to babies, who may be born with yellowing of the skin and eyes, macrocephaly, microcephaly and convulsive crises, in addition to the occurrence of miscarriages.

Contaminated water, undercooked meat from animals with cysts and infected vegetables are the main routes of infection of humans by the parasite. Food hygiene is the main form of disease prevention, because, although there are already vaccines available for sheep, immunizers suitable for humans and other animals are still in the research phase.

Toxoplasmosis can affect all animals, but mainly affects cats, which become infected for the first time when hunting infected prey. In that case, millions of parasitic eggs (oocysts) are shed through the feces over two weeks and take a few days to mature and become infectious to other animals. Despite this, the likelihood of human infection through felines is low.