Rift Valley Fever (RVF) Overview
Rift Valley Fever primarily affects animals such as sheep, goats, cattle, and camels. In early November 2025, the World Health Organization (WHO) confirmed an outbreak of RVF in Mauritania and Senegal, Western Africa. Over 404 human cases and 42 deaths were reported between September and October 2025, with a case fatality rate of approximately 10%.
Significance of RVF
- Recognized by WHO as a notifiable animal disease due to its potential for rapid spread.
- Listed in WHO’s R&D Blueprint for Action to Prevent Epidemics as a priority pathogen with epidemic potential.
- Potential use as a biological weapon highlights importance of global surveillance.
Historical Background
- First recognized in Kenya's Rift Valley in the 1930s.
- Spread to Egypt in 1977, and crossed into Saudi Arabia and Yemen by 2000.
Transmission and Symptoms
- Caused by a Phlebovirus in the Phenuiviridae family.
- Transmitted primarily through mosquito bites or direct contact with infected animals.
- Incubation period: 2 to 6 days.
- Symptoms: High fever, muscle and joint pain, headache, weakness, and sometimes nausea.
- Severe cases can lead to ocular disease, meningoencephalitis, or haemorrhagic fever.
Diagnosis and Treatment
- Diagnosis requires laboratory testing using molecular or serological methods.
- No specific antiviral treatment; care is supportive.
- No licensed human vaccine, but experimental vaccines exist for high-risk groups.
Prevention and Control
- Outbreak management involves a One Health approach linking human, animal, and environmental health.
- Surveillance for unusual livestock abortions, movement restrictions, and vector control are vital.
- Public health education emphasizes personal protective measures and early reporting.
Impact and Preparedness
- RVF is a medical and economic threat to pastoral communities, affecting livestock and food security.
- India has not reported RVF but emphasizes preparedness through diagnostic and surveillance measures.
The WHO has not recommended travel or trade restrictions despite the outbreak in Mauritania and Senegal, but the disease's pattern following heavy rains remains a concern in Africa and the Arabian Peninsula.
