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Crimean-Congo Hemorrhagic Fever: first detection of the virus on ticks collected from cattle farms in the south of France
Following the detection, on October 6, 2023, of the Crimean-Congo hemorrhagic fever virus in ticks of the Hyalomma genus collected on cattle raised in the Eastern Pyrenees, Public Health France takes stock of the situation and recalls the recommendations to adopt.
Published on October 24, 2023
As part of a study aimed at detecting its presence in France, Cirad (Center for international cooperation in agricultural research for development) detected the Crimean-Congo Hemorrhagic Fever (CCHF) virus in ticks from the Hyalomma marginatum species collected from cattle in the Pyrénées-Orientales. These first analyzes were confirmed by the CNR (National Reference Center for Viral Hemorrhagic Fevers) of the Pasteur Institute, thus establishing for the first time the presence of the virus in France. Public Health France takes stock of the risks for the population and recalls the recommendations to prevent tick bites for breeders, farmers, hikers and all people likely to frequent places (pastures, scrubland in particular) where these ticks are found on the Mediterranean rim.
What are the possible risks for the population?
Public Health France analyzed the situation in collaboration with its partners from Anses, Cirad and the CNR of FHV in a One Health approach.
In humans, CCHF virus infection most often remains asymptomatic or minimally symptomatic. However, the virus can be responsible for hemorrhagic fever, which can be severe with a fatality rate of 5 to 30%.
The virus is generally transmitted by the bite of an infected adult Hyalomma tick . Transmission to humans is also possible through direct contact with the blood or bodily fluids of an infected animal or human (during the short period during which the virus circulates in the blood).
No autochthonous case (infection acquired on French territory) has been detected in humans in France to date.
A more in-depth multidisciplinary assessment of the risk of occurrence of human cases will be carried out for the next tick activity season in spring 2024 and in subsequent years.
Where is the Hyalo mma marginatum tick found in France?
Originally from Africa and Asia and introduced mainly by migratory birds from Africa, the Hyalomma marginatum tick has been present for several decades in Corsica and was detected from 2015 by CIRAD on the Mediterranean coast. Currently, there is no active surveillance of ticks on a national scale in France, whatever the species. This surveillance was recommended by ANSES in its opinion of May 2023. Several studies have been or are being carried out in order to assess the presence in France of these ticks and certain infectious agents that they can carry. CIRAD was thus able to show that the Hyalomma marginatum tick was present throughout the Mediterranean and was likely to expand further north in the future, under the effect of climate change.
As part of the scientific studies carried out by this research institute, analyzes carried out in 2022 and 2023 on Hyalomma marginatum ticks collected from cattle in the Pyrénées-Orientales, revealed for the first time the presence of genetic material of the virus of the FHCC, when until now it was only detected indirectly by the presence of antibodies in domestic and wild ungulates. Future investigations will seek to find out whether the circulation of the virus is more widely distributed in the south of France.
The CNR-FHV (National Reference Center for Viral Hemorrhagic Fevers) of the Pasteur Institute has confirmed these results and is currently conducting sequencing analyzes of the virus to understand the origin of the strains found.
Crimean-Congo hemorrhagic fever virus around the world
Although the Hyalomma marginatum tick is present on the Mediterranean coast and in Corsica, no human case of CCHF has yet been observed in France. On the other hand, a dozen indigenous human cases of CCHF have been reported in Spain since 2016, some of them in healthcare professionals.
This disease is endemic in Africa, including North Africa, Asia, and particularly common in certain regions in Turkey. It is also present in some Eastern European countries.
What is Crimean-Congo hemorrhagic fever and what are the symptoms?
CCHF is a disease caused by a virus of the Nairovirus family whose main vectors are ticks of the Hyalomma genus . In humans, it is generally limited to a flu syndrome with digestive problems. In certain cases, it can nevertheless worsen and result in a hemorrhagic syndrome (potentially severe bleeding), with a risk of death of up to 30% in certain countries. The management of CCHF is mainly based on symptomatic treatment in a hospital setting.
Symptoms of Crimean-Congo hemorrhagic fever
Generally, the symptoms appear suddenly and mainly correspond to fever, myalgia (muscle pain), digestive disorders, dizziness, stiffness and pain in the neck, back pain, headache, eye sensitivity. and photophobia (feeling of discomfort caused by light). In severe cases, these symptoms may be followed by hemorrhage, shock and multiorgan failure.
What to do in case of a tick bite?
In the event of a sting, you must monitor your general condition and consult a doctor quickly if symptoms appear in the month following exposure.
How is Crimean-Congo hemorrhagic fever transmitted?
In human health, contamination by the CCHF virus occurs through the bite of adult ticks of the Hyalomma genus . The Hyalomma marginatum tick is a relatively large hard tick (5mm), recognizable by its long rostrum and its two-colored legs (whitish rings at the joints).
The frequency of human bites is assumed to be low, as these ticks have no particular appetite for humans. In addition, they are generally better visible than other species of ticks because they are a little larger and it is easier to spot them before they bite.
The CCHF virus can also be transmitted by contact with bodily fluids of infected viremic humans or animals, knowing that the latter only remain viremic for around ten days. There is no airborne transmission. CCHF virus is an RNA virus that is not resistant in the environment. The virus is not transmitted through consumption of raw milk dairy products and transmission through consumption of meat from infected animals has never been reported. In France, the Hyalomma marginatum tick , in its adult form, bites domestic and wild ungulates (cattle, horses, small ruminants, deer) and occasionally humans. It is likely to transmit the virus through its bite but is only active in spring between April and July. The risk of transmission by bite of these ticks present in the environment and by the fluids of these animals is therefore seasonal.
Ticks attached to livestock do not constitute a bite risk for humans, since they are not capable of re-biting after the bite on the animal 1 , 2 . Furthermore, the immature forms of these ticks (nymphs) feed on small mammals, such as hares, until October and can infect these animals. Therefore, vigilance is recommended when hunting these animals when skinning them (risk linked to contact with bodily fluids).
How to protect yourself from tick bites?
In the absence of a vaccine against CCHF, the main way to reduce the risk of infection in humans is to protect against tick bites:
https://www.santepubliquefrance.fr/l...d-de-la-france
Following the detection, on October 6, 2023, of the Crimean-Congo hemorrhagic fever virus in ticks of the Hyalomma genus collected on cattle raised in the Eastern Pyrenees, Public Health France takes stock of the situation and recalls the recommendations to adopt.
Published on October 24, 2023
As part of a study aimed at detecting its presence in France, Cirad (Center for international cooperation in agricultural research for development) detected the Crimean-Congo Hemorrhagic Fever (CCHF) virus in ticks from the Hyalomma marginatum species collected from cattle in the Pyrénées-Orientales. These first analyzes were confirmed by the CNR (National Reference Center for Viral Hemorrhagic Fevers) of the Pasteur Institute, thus establishing for the first time the presence of the virus in France. Public Health France takes stock of the risks for the population and recalls the recommendations to prevent tick bites for breeders, farmers, hikers and all people likely to frequent places (pastures, scrubland in particular) where these ticks are found on the Mediterranean rim.
What are the possible risks for the population?
Public Health France analyzed the situation in collaboration with its partners from Anses, Cirad and the CNR of FHV in a One Health approach.
In humans, CCHF virus infection most often remains asymptomatic or minimally symptomatic. However, the virus can be responsible for hemorrhagic fever, which can be severe with a fatality rate of 5 to 30%.
The virus is generally transmitted by the bite of an infected adult Hyalomma tick . Transmission to humans is also possible through direct contact with the blood or bodily fluids of an infected animal or human (during the short period during which the virus circulates in the blood).
No autochthonous case (infection acquired on French territory) has been detected in humans in France to date.
A more in-depth multidisciplinary assessment of the risk of occurrence of human cases will be carried out for the next tick activity season in spring 2024 and in subsequent years.
Where is the Hyalo mma marginatum tick found in France?
Originally from Africa and Asia and introduced mainly by migratory birds from Africa, the Hyalomma marginatum tick has been present for several decades in Corsica and was detected from 2015 by CIRAD on the Mediterranean coast. Currently, there is no active surveillance of ticks on a national scale in France, whatever the species. This surveillance was recommended by ANSES in its opinion of May 2023. Several studies have been or are being carried out in order to assess the presence in France of these ticks and certain infectious agents that they can carry. CIRAD was thus able to show that the Hyalomma marginatum tick was present throughout the Mediterranean and was likely to expand further north in the future, under the effect of climate change.
As part of the scientific studies carried out by this research institute, analyzes carried out in 2022 and 2023 on Hyalomma marginatum ticks collected from cattle in the Pyrénées-Orientales, revealed for the first time the presence of genetic material of the virus of the FHCC, when until now it was only detected indirectly by the presence of antibodies in domestic and wild ungulates. Future investigations will seek to find out whether the circulation of the virus is more widely distributed in the south of France.
The CNR-FHV (National Reference Center for Viral Hemorrhagic Fevers) of the Pasteur Institute has confirmed these results and is currently conducting sequencing analyzes of the virus to understand the origin of the strains found.
Crimean-Congo hemorrhagic fever virus around the world
Although the Hyalomma marginatum tick is present on the Mediterranean coast and in Corsica, no human case of CCHF has yet been observed in France. On the other hand, a dozen indigenous human cases of CCHF have been reported in Spain since 2016, some of them in healthcare professionals.
This disease is endemic in Africa, including North Africa, Asia, and particularly common in certain regions in Turkey. It is also present in some Eastern European countries.
What is Crimean-Congo hemorrhagic fever and what are the symptoms?
CCHF is a disease caused by a virus of the Nairovirus family whose main vectors are ticks of the Hyalomma genus . In humans, it is generally limited to a flu syndrome with digestive problems. In certain cases, it can nevertheless worsen and result in a hemorrhagic syndrome (potentially severe bleeding), with a risk of death of up to 30% in certain countries. The management of CCHF is mainly based on symptomatic treatment in a hospital setting.
Symptoms of Crimean-Congo hemorrhagic fever
Generally, the symptoms appear suddenly and mainly correspond to fever, myalgia (muscle pain), digestive disorders, dizziness, stiffness and pain in the neck, back pain, headache, eye sensitivity. and photophobia (feeling of discomfort caused by light). In severe cases, these symptoms may be followed by hemorrhage, shock and multiorgan failure.
What to do in case of a tick bite?
In the event of a sting, you must monitor your general condition and consult a doctor quickly if symptoms appear in the month following exposure.
CCHF is one of the notifiable human diseases (DO) in the same way as other viral hemorrhagic fevers. Any case must be declared by form without delay as soon as suspicion is substantiated by an infectious disease specialist referred to the health authorities (Regional Health Agencies) by health professionals in order to organize diagnostic and therapeutic care in a dedicated and secure care sector.
How is Crimean-Congo hemorrhagic fever transmitted?
In human health, contamination by the CCHF virus occurs through the bite of adult ticks of the Hyalomma genus . The Hyalomma marginatum tick is a relatively large hard tick (5mm), recognizable by its long rostrum and its two-colored legs (whitish rings at the joints).
The frequency of human bites is assumed to be low, as these ticks have no particular appetite for humans. In addition, they are generally better visible than other species of ticks because they are a little larger and it is easier to spot them before they bite.
The CCHF virus can also be transmitted by contact with bodily fluids of infected viremic humans or animals, knowing that the latter only remain viremic for around ten days. There is no airborne transmission. CCHF virus is an RNA virus that is not resistant in the environment. The virus is not transmitted through consumption of raw milk dairy products and transmission through consumption of meat from infected animals has never been reported. In France, the Hyalomma marginatum tick , in its adult form, bites domestic and wild ungulates (cattle, horses, small ruminants, deer) and occasionally humans. It is likely to transmit the virus through its bite but is only active in spring between April and July. The risk of transmission by bite of these ticks present in the environment and by the fluids of these animals is therefore seasonal.
Ticks attached to livestock do not constitute a bite risk for humans, since they are not capable of re-biting after the bite on the animal 1 , 2 . Furthermore, the immature forms of these ticks (nymphs) feed on small mammals, such as hares, until October and can infect these animals. Therefore, vigilance is recommended when hunting these animals when skinning them (risk linked to contact with bodily fluids).
How to protect yourself from tick bites?
In the absence of a vaccine against CCHF, the main way to reduce the risk of infection in humans is to protect against tick bites:
- when walking in nature, wear closed shoes and light-colored covering clothing in order to better spot ticks on the surface of the fabric, put on the pants inside the socks;
- avoid walking among grass, bushes and low branches and favor marked paths;
- possibly use skin repellents with marketing authorization (AMM), while respecting the recommendations for use ( recommendations for 2023 travelers for repellents );
- inspect yourself when returning from your walks in the forest, in the scrubland and scrubland or in the garden, particularly at the level of the folds of the skin without forgetting the scalp;
- in the event of a bite, immediately remove the attached ticks using a tick remover, fine tweezers or, failing that, your nails and disinfect the area;
- monitor your general condition and promptly consult a doctor if symptoms appear within the month following exposure.
To know more :
- Crimean-Congo hemorrhagic fever: emergence in France is possible | Anses - National Agency for Food, Environmental and Occupational Health Safety
- OPINION and REPORT from ANSES relating to the analysis of the risks to human and animal health linked to ticks of the Hyalomma genus in France
- The striped-legged tick under surveillance | Cirad
https://www.santepubliquefrance.fr/l...d-de-la-france
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