Building the Future of Biodefense

Recommendation: Lassa fever is endemic in Nigeria with cases peaking during the dry season (Dec-Apr). Organizations in Nigeria should take measures to ensure rodent-free facilities. Evaluate existing pest control protocols if they are not regularly reviewed and updated. Any rodent droppings should be cleaned with bleach to limit infectious aerosol generation. Employees should always wear gloves and N95 (or equivalent) masks when handling rodents or their droppings.

Situation: Nigeria is approaching the peak Lassa fever season. While cases and deaths remain low currently, increases in incidence typically start in early December. Nigeria reported 8,556 suspected cases, 7 probable, and 976 confirmed cases so far this year, including 178 confirmed deaths. Case counts this year are lower compared to the same period last year, though the case fatality rate is higher at 18.2% compared to 16.4%. Only 21 states detected cases, 7 fewer states than last year. [Confidence: Very High]

Recommendation: Organizations operating in evacuation zones and the surrounding area of Indonesia's Semeru volcano eruption should inform employees of the health risks from volcanic gases and ash, which can cause mild to severe respiratory effects. Organizations should follow local guidance, monitor air quality, avoid ashfalls, keep doors and windows closed, turn off all heating and air conditioning units and fans, and minimize outdoor exposure. Employees working outside should adhere to safety regulations and use respiratory protection, eye protection, and wear long sleeves and long pants to avoid skin irritation. Anyone developing symptoms should seek medical care promptly. The volcanic eruption may also disrupt aviation and travel at times.

Situation: According to media sources, Indonesia's Mount Semeru volcano erupted on Wednesday, sending ash up to 5.6 km into the sky and prompting officials to raise the threat level to its highest and expand the danger zone to 8 km from the crater. Clouds of hot ash and a mixture of rock, lava, and gas traveled up to 7 km down the slopes, leading to the evacuation of over 300 residents in Lumajang District. Officials were struggling to rescue 178 people stranded at a monitoring post 4.5km from the crater, but so far, they remain safe. The Australian Bureau of Meteorology's Volcanic Ash Advisory Centre issued a red aviation alert following the eruption, but media reported that flights between Australia and Denpasar were unaffected at this time. Semeru's last major eruption in December 2021 left 51 people dead and several hundred others burned in villages that were buried in layers of mud. [Confidence: Very High]

Recommendation: Usutu virus is a mosquito-borne virus similar to West Nile virus, which primarily causes disease in birds but can infect people. The emergence of the Usutu virus in Europe does not require new actions. Organizations should continue to take actions to reduce mosquito populations and habitats at their facilities. This includes eliminating sources of standing water and applying insecticides to outdoor water storage containers. Employees can reduce infection risk by wearing clothing that covers skin, using mosquito repellents, and emptying standing water.

Situation: The Blood and Tissue Bank of the Balearics (BSTIB) identified Spain’s 1st indigenous case of Usutu virus in a blood donor. Detected in July 2024 in Mallorca, Spain, the initial sample showed reactivity in routine tests for West Nile virus. After being sent to the National Reference Laboratory for Arboviruses, specific and neutralization tests confirmed infection as Usutu virus, an emerging arbovirus in Europe transmitted by mosquitoes of the Culex genus. Two additional cases were later confirmed in Catalonia. All 3 cases had no recent travel, indicating local virus circulation. The findings, published in Transfusion, highlight that standard West Nile virus screening can also detect Usutu virus, enhancing transfusion safety during periods of high mosquito activity. [Confidence: Very High]

Recommendation: This death serves as a reminder that influenza can be a severe disease. Influenza and other respiratory diseases are expected to impact employee absenteeism due to illness or caregiving duties. Organizations in California should provide flexible work schedules to support employees making vaccine appointments for themselves or family members.

Situation: Los Angeles County health officials confirmed their 1st influenza-related death of the 2025-2026 respiratory season. This individual was an older resident with underlying health conditions and had not received an influenza vaccination this season. Influenza activity in the county is currently low but is expected to increase as the holidays approach, with more travel and indoor gatherings. Health officials advised the public to review their vaccination status and to get vaccinated, as well as practice respiratory hygiene. [Confidence: Very High]