Air sampling at four US airports in 2023 and 2024 detected SARS-CoV-2, the virus that causes COVID-19, in over 98% of samples and influenza A in over 17%, according to a study published in PLOS Global Public Health.

Researchers from the Centers for Disease Control and Prevention led the study, which involved air monitoring in congregate areas at San Francisco International Airport, Newark Liberty International Airport, Washington Dulles International Airport, and Dallas/Fort Worth International Airport. 

The team placed samplers on tables 28 to 30 inches above the floor near customs and immigration inspection areas and international arrivals. Each ThermoFisher AerosolSense unit collected air samples for 10 hours per day, and the sample-collection cartridges were removed after 20 hours of use Monday through Thursday and 30 hours over the weekend.

Correlation of the air samples with aviation wastewater, traveler nasal swabs, and national clinical surveillance data was also tested using data from two airports.

Air sampling complements wastewater monitoring, the researchers said: “This approach is particularly effective for capturing respiratory pathogens from diverse populations, including asymptomatic or pre-symptomatic individuals who might not otherwise engage with clinical testing or contribute to accessible wastewater systems.” 

Polymerase chain reaction (PCR) testing revealed SARS-CoV-2 in 98.3% of 463 air samples and influenza A in 17.2%. While influenza A positivity correlated with that in aviation wastewater, traveler nasal swabs, and national clinical surveillance, SARS-CoV-2 positivity didn’t align well.

Detection of respiratory pathogens through air monitoring may inform targeted mitigation strategies, including enhanced ventilation, air purification, public health messaging, and allocation of public health resources.

Genetic sequencing of SARS-CoV-2 from air samples identified lineages also found in wastewater samples during the same period from the same airports. In addition, it detected 30 viral species and recovered high-quality genomes for SARS-CoV-2, influenza, bocavirus (a virus that mainly causes respiratory tract and gastrointestinal infections in infants and young children), and seasonal coronaviruses. 

“Air detection of viral pathogens within airports and other international points of entry may represent an important component of layered surveillance systems for future pandemic preparedness,” the authors wrote.

“Detection of respiratory pathogens through air monitoring may inform targeted mitigation strategies, including enhanced ventilation, air purification, public health messaging, and allocation of public health resources,” they wrote.

• Yesterday, World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus, PhD, said, "We are now starting to see encouraging signs that we are gaining ground,” in the ongoing fight against the Ebola outbreak in the Democratic Republic of the Congo (DRC). He explained that his optimism was cautiously rooted in the absence of new cases in South Kivu since May and a slowdown in cases in Ituri province. The epicenter remains North Kivu, where cases are “rising fast,” Tedros said. In the past two weeks, weekly case counts have doubled in North Kivu, from 100 to 200 per week. Tedros warned that North Kivu is an area of very high population mobility and said much more work is needed to be done before the outbreak is contained. 
• For the first time in more than 60 years, New World screwworm has been detected in a ranch horse in Texas, according to an update yesterday from the US Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS). The case was detected last week in Presidio County. The parasite was found on the hind limb of the animal. So far this year, the parasitic fly has been detected in 49 animals in Texas and New Mexico. 
• The archipelago nation of Fiji has declared an emergency now that one in 60 adults has HIV. The outbreak was first announced in January 2025, when the country had 2,016 new diagnoses of HIV. Last year, 59 babies were born with HIV acquired from their mothers. The emergency was declared because only 39% of people with HIV in Fiji know they are infected, officials said. The crisis is fueled in part by intravenous drug use and heavy drug trafficking on the islands.