Researchers from Limoges have just demonstrated that the development and spread of toxoplasmosis was linked to the domestication of the feline over the past millennia. This work provides information about the role of humans in the emergence of zoonoses, and they can contribute to the development of a vaccine.
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Domestic cats accompany us, observe us, soften us … and they are often carriers of toxoplasmosis. It is a zoonosis, that is, a disease that can be transmitted from animals to humans. Most often it does not have serious consequences, but it can be dangerous for people with weak immune systems, or for future babies when a pregnant woman is affected.
This disease is caused by a parasite called Toxoplasma gondii. It is already well known, but its development and spread over the centuries still had its dark side. In a study published in Nature Communications, scientists from the University of Limoges, members of the Epimact* team, reveal today that domestic cats are indeed the main vectors of the parasite over time and worldwide.
To reach this conclusion, the researchers simultaneously examined the evolution of the parasite genome in recent history. 40,000 years.
Specifically, Toxoplasma gondii is a parasite of Felidae. However, strains suitable for domestic cats are different from those suitable for wild felines. However, the cat is the only cat that is in direct contact with humans. The researchers were thus able to draw a parallel between the spread of the parasite and the travels of domestic cats.
10,000 years ago, the Phoenicians and Egyptians began adopting wild cats. These domestic cats will then accompany humans on their migrations to Africa, Asia and Europe, bringing their parasites with them.
From the 16th century we move from the old to the new world: with cats to hunt rats in their holds, merchant ships bring toxoplasmosis from Europe to America. Lokman Galal, lead author of the study, explains what piqued his curiosity: “We had very close tribes on both sides of the sea, and these tribes were all domestic tribes.”
Besides not worrying a little more when our cat gives us a scary look, this study can have concrete applications. Aurélien Mercier, co-author, details: “We see the human impact in the emergence of a very important zoonosis. We understand its mechanism”. The researcher goes on: “The identified genes could be targets for a vaccine. And vaccinating cats can short-circuit transmission of the parasite.”
Cat owners suspected it, but the work carried out in Limoges confirms that this elusive animal has not yet revealed all its secrets…
*The Epimact team, Epidemiology of chronic diseases in the tropics, brand Inserm and IRD, receives support from the National Research Agency.