Building the Future of Biodefense

Recommendation: Organizations and employees should avoid all contact with the Potomac River and surrounding soil, including swimming, boating, wading, or fishing, while the sewage spill and repairs continue to reduce the risk of infection. Employees should practice good hand hygiene after potential exposure, prevent pets from drinking from the river, rely on safe drinking water, follow guidance from local authorities, and seek medical attention if gastrointestinal symptoms develop after possible contact.

Situation: The District of Columbia declared a local emergency and requested federal support after the Potomac Interceptor sewage break. The request seeks cost reimbursement, immediate federal aid for water monitoring and engineering, and long-term infrastructure improvements. According to media sources, the rupture of the 60-year-old Potomac Interceptor on 1/19 caused one of the largest sewage spills in US history, releasing millions of gallons of waste into the Potomac River. Repairs are expected to take months, with full replacement potentially taking up to 10 months. E. coli, Staphylococcus aureus, and antibiotic-resistant MRSA have been detected in the river, and officials advise residents to avoid contact with the water. DC Water built a bypass, but sporadic overflows continue. [Confidence: Very High]

Recommendation: Aedes aegypti is not widespread throughout mainland Chile, but it is established in Argentina. The presence of the invasive mosquitoes alone does not indicate that those diseases are circulating, as the mosquitoes must first bite an infected individual before transmitting a disease to others. Organizations in Chile and Argentina should reduce mosquito habitats by eliminating sources of standing water and applying insecticides to outdoor water storage containers. The temporary border closure may lead to travel delays.

Situation: The Los Libertadores Border Complex between Chile and Argentina will be temporarily closed from 2/19 to 2/20 after officials detected a suspected Aedes aegypti mosquito, a known carrier of dengue, chikungunya, Zika, and yellow fever. The closure allows for chemical treatment to control the vector. Transit will be suspended at the Guardia Vieja (Chile) and Uspallata (Argentina) border area. The crossing is expected to reopen at noon on 2/20. This follows a similar detection of the mosquito at Santiago airport in late January (see PHC alert 1/30). [Confidence: Very High]