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3 cases of Lassa fever were reported in the UK, including one death, in February. Symptoms, risks and transmission… What is this virus?
3 cases of Lassa fever, one of whose patients died, have been declared in the United Kingdom, according to a press release from the British Health Security Agency, British health authority. The first two cases were announced on February 9, then the last, having unfortunately succumbed to the consequences of the disease, on February 11.
They came from West Africa
The 3 patients did not contract the Lassa fever virus on English soil. “All reported cases relate to people from one and the same family who recently returned from a trip to West Africa“, specify the authors of the press release.
Lassa fever is a zoonosis, that is to say, a disease transmitted by animals, the “plurimammary rat” or “natal rat”. Transmission occurs through contact with soiled objects or ingestion of food contaminated with the virus secreted in the rodent’s urine and droppings, explains the Center for Disease Control and Prevention (CDC) in the United States.
The Lassa virus in humans is a relatively rare disease except in West Africa where its virulence is qualified as endemic, that is to say which circulates constantly and regularly for a long time. “The annual number of cases of Lassa virus infection in West Africa is estimated at between 100,000 and 300,000, with nearly 5,000 deaths. These are unfortunately crude estimates because surveillance of cases of the disease does not is not carried out in a uniform way.” Transmission occurs more easily in this area, because the animal vector of the virus, in search of food, often lives inside and around houses.
Lassa fever: the signs
The main symptoms are mostly (80%) mild or barely noticed. One may suffer from mild fever, general weakness and headaches. “However, in 20% of cases of infections, the disease progresses to more serious symptoms, including bleeding (in the gums, eyes or nose, for example), difficulty breathing, repeated vomiting, swelling of the face, pain in the chest, back and abdomen, and shock.”, say the specialists. Only 1% of cases of Lassa virus infection cause death.
The English health authorities wanted to reassure the population by recalling that on their territory, cases remain rare. “There have been less than 8 reported cases of Lassa fever in the UK, the last in 1990, the last two in 2009”, insists the press release.