FAO Issues Urgent El Niño Warning for Rift Valley Fever in Eastern Africa

Six Countries Face Highest Risk as Heavy Rains Raise Outbreak Concerns

Source: FAO and IGAD | Risk outlook: October 2026–January 2027

The Food and Agriculture Organization of the United Nations (FAO) and the Intergovernmental Authority on Development (IGAD) have issued an urgent warning that unusually heavy rainfall and flooding associated with strong El Niño conditions could increase the risk of Rift Valley fever (RVF) outbreaks across Eastern Africa. Their alert calls on countries to strengthen disease surveillance, prepare veterinary supplies and vaccines, and coordinate animal and human health responses before outbreaks emerge.

Key facts: FAO–IGAD RVF alert

Eastern Africa enters a heightened RVF preparedness period

The FAO–IGAD alert comes as the region prepares for an exceptionally wet season. According to FAO’s October 2026 risk assessment, conditions favourable to RVF transmission are expected to increase across much of Eastern Africa through January 2027. The agency warns that heavy rainfall and flooding could create extensive mosquito-breeding habitats, while livestock movements could facilitate the spread of infection between affected areas.

• Ethiopia: Southern areas are among those forecast to receive very heavy rainfall.

• Kenya: Heavy rainfall is expected in areas where flood-related mosquito proliferation could elevate transmission risk.

• Somalia: Southern and central areas face a particularly strong rainfall signal, alongside increased flood risk.

• South Sudan: Wetter-than-normal conditions and renewed rainfall in some areas add to preparedness concerns.

• Tanzania: FAO’s forecasting tool currently identifies Tanzania as having the largest area classified as suitable for RVF transmission.

• Uganda: Wetter-than-normal conditions are expected, and FAO anticipates that suitable transmission areas could expand further.

The assessment also identifies increasing risk in Burundi and Rwanda. Lower but growing risks extend to the Comoros, northern Madagascar, Mayotte, southwestern Saudi Arabia and western Yemen. These are risk assessments, not confirmations of active outbreaks in every listed location.

Why El Niño can trigger Rift Valley fever outbreaks

FAO says the current El Niño conditions are comparable to those observed during 1997–1998, when Eastern Africa experienced one of its largest recorded RVF epidemics and animal epizootics. This historical comparison underlines the need for preparedness, but it does not mean that the current season will necessarily reproduce the scale or geographical pattern of the earlier event.

Livestock health: the main clinical and production risks

RVF can affect animal health and farm economics simultaneously. Its impact is particularly serious when susceptible animals are pregnant or very young.

These are recognised disease impacts, not estimates of losses expected in the 2026–27 season. The alert does not quantify forecast mortality, abortion rates or the number of farms likely to be affected.

For pastoral and smallholder systems, even a geographically concentrated outbreak can have effects beyond the directly infected herd. Loss of young animals can weaken future herd recovery, while reproductive losses can reduce subsequent production. Movement restrictions and disruption to live-animal and animal-product trade can add further economic pressure. FAO identifies trade disruption and socioeconomic impacts among the consequences of RVF events.

Human health: why RVF is a One Health priority

Although RVF is often discussed as a livestock disease, it is also a public-health threat. People can become infected through mosquito bites or by handling blood, organs and other tissues from infected animals. High-risk exposure situations can include slaughtering infected animals and assisting with animal births or handling aborted material.

Most human infections are mild, but some patients develop severe disease, including haemorrhagic, ocular or neurological complications; fatal cases can occur. The implication is that veterinary surveillance must be linked to public-health monitoring, particularly when unexplained livestock abortions or deaths appear in areas experiencing heavy rainfall.

The One Health approach advocated by FAO and IGAD therefore has practical importance: veterinary authorities, public-health agencies, laboratories and environmental monitoring teams need to share information and coordinate risk assessments rather than operate as separate systems.

FAO’s early-warning system: turning climate forecasts into veterinary action

A key element of the alert is FAO’s Rift Valley Fever Early Warning Decision Support Tool (RVF-DST). The platform combines satellite-derived rainfall and vegetation data, climate forecasts, disease-surveillance information and expert analysis to identify areas where environmental conditions may favour transmission. FAO says it can forecast elevated-risk areas up to three months ahead.

The October 2026 assessment identifies Tanzania as having the largest area currently classified as suitable for transmission, followed by Ethiopia, Kenya, South Sudan and southern Sudan. New suitable areas have also emerged in southern Somalia, Rwanda and Burundi, with further expansion expected if heavy rainfall continues.

This distinction matters for decision-makers: a climate-based suitability map is an early-warning instrument, not an outbreak confirmation map. Its value lies in allowing veterinary and public-health services to direct resources towards potentially exposed areas before clinical cases or laboratory confirmation force an emergency response.