The Ministry of Health announced on Thursday, May 2, that a first case of Lassa fever, a viral hemorrhagic fever endemic in certain African countries, had been detected in France. The patient, hospitalized in Ile-de-France, is a soldier returned from abroad, whose state of health does not, however, cause “any concern”, the ministry said in a press release. “A thorough epidemiological investigation is underway to determine the people who may have been in risky contact with the patient.”
What is Lassa fever and how is the disease transmitted? This is a hemorrhagic fever, notifiable. The majority of cases (80%) are asymptomatic but it can also cause vomiting, nausea, abdominal pain, and headaches, according to the Ministry of Health. “In severe cases, the symptoms then worsen, with the appearance of edema, hemorrhagic signs, and more rarely encephalitis,” specifies the Pasteur Institute.
“Lassa fever is extremely serious for pregnant women, frequently leading to the death of the mother and systematically to that of the fetus. In patients who survive the infection, the fever disappears approximately 10 days after the start of the symptoms. symptoms, but severe fatigue, malaise and dizziness can persist for several weeks,” indicates the foundation. Problem is, there is currently no vaccine against the virus that causes Lassa fever. A broad-spectrum antiviral against RNA viruses, ribavirin, can be administered but its effectiveness would not be satisfactory. In addition, it should be administered as early as possible, while the disease, often asymptomatic, is not always detected. Vaccines are nevertheless being studied.
The virus takes its name from the town of Lassa in northern Nigeria, where it was first identified in 1969. It is endemic in several West African countries, “where it infects 100,000 to 300,000 people per year, of whom 5,000 to 6,000 die”, specifies the Pasteur Institute. Political unrest, leading to population displacement in affected areas, is one of the causes of the increase in cases.
Transmissible by direct contact
The virus can be transmitted from person to person “by direct contact with the blood, urine, excrement or other organic secretions of an infected person. The risk of occurrence of secondary cases is therefore limited to people who have had direct contact with the biological fluids of the patient, in particular the health personnel who took care of him”, recalls the ministry. Initially, it is transmitted from animals to humans through contact with a small rodent living nearby or in homes, the Mastomysnatalensis, also called “African rat”.
Contact persons at risk “were contacted by the health authorities”, he added. You must “monitor the appearance of symptoms for 21 days after the last risky contact” and “if symptoms appear, including fever, isolate yourself and contact a doctor”.