Building the Future of Biodefense

Recommendation: Heavy rainfall and flooding can disturb bacteria in soil and contaminate water, increasing the risk of diseases like leptospirosis and melioidosis. Debris and stagnant water in the aftermath of flooding create more mosquito breeding areas, increasing the risk of mosquito-borne diseases. Organizations in Thailand, Indonesia, Malaysia, and Sri Lanka should advise employees working outdoors in areas with recent heavy rainfall or flooding to cover open skin wounds, wear boots, and use masks. Employees should avoid contact with floodwater when possible. Employees can also take steps to prevent mosquito bites by wearing protective clothing and using insect repellent, and eliminating standing water near their homes.

Situation: According to media sources, severe flooding and landslides killed more than 1,100 people in the past week and affected millions across Thailand, Indonesia, Malaysia, and Sri Lanka. Heavy rains, reported as historic in some areas, hindered search and rescue operations and caused widespread destruction, including destroyed homes, damaged medical facilities, power outages, and disruptions to food access. Vietnam also reported severe impacts from the heavy rains earlier (see PHC alert 11/24). [Confidence: Very High]

Recommendation: Informational update only.

Situation: Indonesia officially ended its vaccine-derived poliovirus type 2 outbreak, which began in 2022 after years of low vaccination coverage. Following nearly 60 million additional vaccine doses, two nationwide vaccination campaigns, and improvements in routine immunization and acute flaccid paralysis surveillance, no poliovirus has been detected in children or the environment since June 2024. After multiple independent assessments confirmed the absence of new cases and the quality of the response, the World Health Organization declared the outbreak closed on 11/19. [Confidence: Very High]

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]