Indeed, the number of infections with this virus transmitted by ticks has increased in Europe. In the fall of 2023, Public Health France reported its identification in a species of invasive ticks established in the south of the country. What do you need to know?
What is Congo fever?
It is a disease that affects both animals, particularly cattle, and humans.
More precisely referred to as “Crimean-Congo hemorrhagic fever”, it is caused by a virus generally transmitted by tick bites. It is the “Hyalomma marginatum” tick, with striped legs and a particularly large size – almost a centimeter – which can pass the virus from one individual or animal to another, via the blood. which she absorbed.
“Crimean-Congo hemorrhagic fever” is caused by a virus generally transmitted by bites from “Hyalomma marginatum” ticks, with striped legs.
Wikimedia cc-by Daktaridudu
Most of the time, an infected person has few or no symptoms, which are similar to a little flu. But the disease can sometimes degenerate into “hemorrhagic fever”, with uncontrolled bleeding. It can then be fatal in 10% to 40% of cases, according to figures from the World Health Organization (WHO).
No treatment
This risk must, however, be put into perspective because it largely depends on the state of the health system, which varies greatly between rich and developing countries.
Furthermore, no treatment has really proven effective against this disease. There is therefore little choice but to let it take its course while seeking to soothe the symptoms.
Why are we talking about it now?
This virus has been detected in France twice in recent months. First in the Pyrénées-Orientales, at the end of 2023, then in Corsica, at the beginning of 2024. Until then, despite the proven presence of giant ticks in multiple departments, there was no indication that the virus was present in France.
However, the disease has been circulating for decades in Africa, the Middle East and the Balkans. On the border between these latter regions, Turkey has been particularly hard hit, sometimes with a thousand cases per year. But, as with other diseases such as dengue, the virus is now found in countries where it was previously absent. A few human cases of Congo fever have been recorded in Spain for around ten years.
“Climate change has been proven to be one of the factors that favors the circulation of the virus,” recalls a study published in 2023 in the journal Emerging Infectious Diseases.
What risk in France?
The virus has so far only been spotted in France in giant ticks. Only one case of hemorrhagic fever has been recorded in the country, and the patient had clearly contracted it abroad.
The fact remains that “the fact of having detected this virus in ticks in the South of France still suggests a possibility of emergence of this disease in the coming years”, warned veterinarian Laurence Vial this last week, during a press briefing from the ANRS, a research agency specializing in infectious diseases.
The short or medium term perspective would not be a major epidemic, but “perhaps like in Spain with a few cases per year”, suggests Laurence Vial, who participated in the recent detection of the virus in France.
How to prepare for it?
Even if the risk of transmission to humans is currently considered low on French territory, health authorities are already calling for common sense precautions. “The main way to protect yourself against Crimean-Congo hemorrhagic fever is to avoid tick bites by adopting individual protection measures, in spring and summer, in places where the tick is installed,” underlines the agency Public health France.
