On June 14, the World Health Organization (WHO) was informed of the laboratory confirmation of a Lassa fever case in Guéckédou prefecture, Nzérékoré region.
The case is a 45-year-old male, biologist, who travelled to Guéckédou prefecture on 13 May 2025.
On 16 May 2025, he started developing symptoms of fever, headache, difficulty breathing, palpitations, cough, anorexia and self-medicated for malaria for three days with no clinical improvement.
He was admitted at the Guéckédou prefectoral hospital on 22 May 2025 and tested positive for Lassa fever by Rt-PCR the same day. He was then transferred to the Nongo epidemic treatment center in Conakry.
A death was reported in another confirmed Lassa fever case from Macenta prefecture in Nzérékoré region.
From 1 January to 1 June 2025, two confirmed lassa fever cases with one death (CFR 50%) were reported from Guinea. Investigations and contact tracing are ongoing.
Lassa Fever is an acute viral illness and a viral hemorrhagic fever (VHF). The causative agent is a single-stranded ribonucleic acid (RNA) virus in the family arenaviridae, the Lassa virus. This zoonotic disease is associated with high morbidity and mortality, transmitted by the multi-mammate rat (Mastomys natalensis), one of the most common rats in equatorial Africa.
The virus spreads through:
• Direct contact with urine, feces, saliva, or blood of infected rats.
• Contact with objects, household items, and surfaces contaminated with the urine, feces, saliva, or blood of infected rats.
• Consuming food or water contaminated with the urine, feces, saliva, or blood of infected rats.
• Person-to-person transmission can also occur through direct contact with blood, urine, feces, vomitus, and other body fluids of an infected person.
Lassa fever initially presents like other common illnesses accompanied by a fever, such as malaria. Other symptoms include headache, general body weakness, cough, nausea, vomiting, diarrhea, muscle pains, chest pain, sore throat, and, in severe cases, bleeding from ears, eyes, nose, mouth, and other body openings. The time between infection and the appearance of symptoms of the disease is 3 to 21 days. Early diagnosis and treatment of the diseases greatly increase the chances of patient survival.
People most at risk for Lassa fever are:
• People of all age groups who come in contact with the urine, feces, saliva, or blood of infected rats.
• People living in rat-infested environments.
• People who consume potentially contaminated foodstuff, especially those left open overnight or dried outside in the open.
• People who handle or process rodents for consumption.
• People who do not perform hand hygiene at appropriate times.
• Caretakers of infected persons with poor infection prevention and control measures.
The disease was first discovered in a town called Lassa in Borno State, Nigeria in 1969.