Researchers at the Reference Center for Human and Animal Toxoplasmosis at  the State University of Londrina (UEL) say they have developed the first vaccine against swine toxoplasmosis in the world based on recombinant proteins — a revolutionary technique in the field of immunization, because it is more effective and carries fewer risks. The vaccine is, according to Professor João Luís Garcia, the result of a long research process and gradual advances in knowledge around the world.

Toxoplasmosis is a disease caused by the protozoan Toxoplasma gondii and affects several species of animals, such as birds and mammals (cats, pigs, sheep, goats and horses), which can serve as vectors (temporary hosts) and transmit to humans. The most serious consequence, both for animals and for the sick human being, is abortion. In the case of humans, toxoplasmosis can still leave a series of sequelae in the newborn, such as deafness, hydrocephalus and mental deficiency. Toxoplasma gondii was isolated for the first time in 1908, practically at the same time, by French researchers in Tunisia and Brazilian researchers in São Paulo.

When Professor João Luís' research began, back in the early 1980s, it was still about the epidemiological picture of the disease. At the time, about four out of 10 pigs in Brazil were contaminated with toxoplasmosis oocysts (eggs) and, as there was no vaccine, investment was made in education and other forms of prevention. Tips on how to cook meat well before consuming it were popularized and are still valid today. Currently, João Luís reports, only four out of every 100 pigs are contaminated. However, considering that a single individual can carry millions of oocysts throughout life, there is still reason to be alert, after all, pork is the most consumed meat in the world, and data from the Osvaldo Cruz Foundation state that about a third of the world's population is affected by the disease.

João Luís graduated and did his master's at UEL, doctorate at the University of São Paulo and two post-doctorates: one at São Paulo State University and the other in Scotland. His research trajectory coincides with the advancement of knowledge in the area of ​​immunization. The first vaccines, for example, are called "live vaccines," because they had live microorganisms capable of infecting. They are called "attenuated" when there is a microorganism in them, but it is incapable of generating the disease, and only "provokes" the immune response.

In 1999, the first of many publications in the international journal Veterinary Parasitology initiated a series of advances in the researcher's investigation. Toxovax, a vaccine against sheep and goat toxoplasmosis, had already been created and tested. As the research progressed and was published, it was possible to see improvements. From live vaccines, vaccines based on proteins began to be developed. First, only one was selected, and then the "recombinant proteins," such as the one developed at UEL. It was in 2008 that an invitation came from the United Kingdom for further studies, for a non-nasal vaccine. In 2012, research was published on a vaccine for rectal application in cats and in 2017, another vaccine for cats, already with recombinant proteins. There have also been studies with viral vaccines, without the same success.

Now, research is advancing on the new type of vaccine: DNA, with genetic material. For example, India has developed a DNA vaccine against COVID-19. It is administered through the skin, does not use needles and requires three doses, four weeks apart. 

The DNA vaccine against swine toxoplasmosis from UEL is being tested in mice and the next phase will be the final one, with the test already in swine. The Center has seven research professors and more than 20 graduate students. Professor João Luís also has nine advisees. He highlights the collaboration of the Laboratory of Parasitology and Parasitic Diseases, of the same Department, on this research.

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