Deadly mosquitoes to expand range with climate change
While warming temperatures from climate change pose increasing threats to humans, they will have the opposite effect on some of the world’s most deadly mosquitoes.
New research published April 10 in the Journal of Climate Change and Health projects mosquitoes that can carry viruses for dengue, West Nile, Zika and more will expand their territories as climate change worsens, raising risks of infection for humans.
Researchers at the Los Alamos National Laboratory estimated what climate conditions will be like at the end of the century in North and South America based on greenhouse gas emissions. They then examined what impact those conditions would have on nine species of mosquitoes, finding all would respond “resiliently” under both high and moderate climate change.
Six species of mosquitoes that can transmit disease such as chikungunya, yellow fever and several types of encephalitis are among those that are expected to increase their geographical range. They include several kinds of Culex mosquitoes, which are the primary vector for West Nile virus — currently the most common mosquito-borne disease in the continental U.S.
Two other mosquito species were predicted to shift their territories while one would generally stay in place.
The study findings can help public health officials plan interventions as climate continues to change, researchers said. For example, they predicted diseases carried by Culex mosquitoes will become more common in Canada, while those spread by Aedes mosquitoes will continue to be a threat throughout both North and South America.
Mosquito-borne diseases already cause considerable harm to human health in the region, with more than 4.2 million suspected cases of dengue reported in the Americas in 2024 alone, according to the Pan American Health Organization.
‘Forever chemicals’ found in commonly eaten seafood
Seafood is recognized as a healthy source of omega fatty acids and lean protein. But people who eat it often may be taking in more than just nutrients, a new study shows.
Published April 12 in Exposure and Health, the research found that eating seafood frequently can increase exposure to per- and poly-fluoroalkyl substances, also known as PFAS. The chemicals are used in products such as nonstick coatings, plastics and firefighting foam and often end up in waterways.
Researchers examined seafood purchased from a coastal market, finding the highest levels of PFAS in shrimp and lobster, which had concentrations as high as 1.74 and 3.30 nanograms per gram of flesh, respectively. Concentrations in the other seafood examined — cod, haddock, salmon, scallop and tuna — were less generally under 1 nanogram per gram of flesh.
Researchers suggested that some animals that feed and live on the sea floor, such as shrimp and lobster, may be more vulnerable to PFAS buildup in their bodies. Proximity to sources of PFAS near coasts may also play a role.
The study examined diets of people in New Hampshire, a New England state where people are known to consume high levels of seafood — about an ounce a day. Shrimp, haddock, salmon and canned tuna were most frequently consumed seafood.
On average, people in the U.S. consumed about 20.5 pounds per capita of seafood in 2021, according to the U.S. Department of Agriculture’s Economic Research Service. That amount, which includes fresh, frozen and canned seafood, is the highest on record in more than 30 years.
PFAS are known as “forever chemicals” because of their inability to break down in human bodies or the environment. The chemicals have been linked to cancer, high cholesterol and reproductive problems, among other disorders.
Study researchers called for health guidelines that establish the amount of seafood people can safely consume to limit PFAS exposure.
Schoolkids near roads breathe in more pollutants
Kids who go to school near major roadways are exposed to more traffic-related air pollution inside their classrooms, new research finds.
Researchers looked at air monitoring data collected at more than 70 urban U.S. schools over 10 years, focusing on fine-particle matter, nitrogen dioxide and black carbon. The farther away schools were from major roads, the lower the levels of traffic-related PM2.5, NO2 and BC, according to the study published April 13 in Journal of Exposure Science & Environmental Epidemiology.
In schools about 2 miles from major roads, levels of traffic-related PM2.5 in classrooms were 63% lower. Those schools also had NO2 levels that were a third lower and BC levels that were one-fifth lower than schools near busy roads.
Researchers also examined the amount of greenery around schools, finding it can serve as a protective buffer zone against roadway air pollution.
Schools with green areas within 880 feet of buildings had 64% lower traffic-related PM2.5, 107% lower NO2 and 61% lower BC levels in classroom air than schools with little to no greenness. Decreases were similar even for schools that had green buffers within three-quarters of a mile. The protective boost from greenery ebbed during winter, however, when many trees and other plants in the study’s Northeastern U.S. region lost their leaves.
Prior research has linked classroom exposure to traffic-related air pollutants to respiratory conditions such as asthma and childhood neurodevelopment issues.
Occupational segregation raises fatal injury rates for Hispanic workers
Occupational segregation — in which people are overrepresented in a job category by race or ethnicity — translates to higher injury-related death rates for Hispanic workers.
A new study, published April 12 in the American Journal of Industrial Medicine, found that segregation helped drive disparities in worker deaths that occurred over 25 years in North Carolina.
Of the 280 Hispanic workers who died from on-the-job injuries during the study period, 57% were working in construction. In comparison, construction accounted for 20% of such deaths among Black workers and 25% among white workers. Another 19% of deaths among Hispanic workers occurred in agriculture.
Hispanic workers in North Carolina tend to be overrepresented in the two industries, which have higher on-the-job risks, such as falls, machinery failures and blunt trauma. Overall, Hispanic male workers had twice the rate of work-related injury deaths than white men, the study found.
Hispanic workers who died from a work-related injury also tended to be younger, with an average of 47 life years lost, compared to 37 among Black workers and 36 among White workers.
By industry, Hispanic workers were also overrepresented in food and wood manufacturing. Black workers were overrepresented in construction, food manufacturing, water utilities and transportation, while white workers were overrepresented in finance, insurance, real estate and automotive services and sales.
Other public health news of note this week includes:
• The Mine Safety and Health Administration issued its final rule to protect mine workers from exposure to silica dust, which is expected to avoid more than 3,700 lifetime deaths from related illnesses.
• Climate change is contributing to a upsurge in immune-related health issues such as asthma, allergies and certain cancers, says new research in Frontiers in Science. Increases in pollen, wildfires, dust storms and more are part of the problem.
• Stationary combustion turbines will continue to be subject to toxic emission regulations, the Environmental Protection Agency confirmed April 15. Located at power plants, landfills and industrial facilities, the turbines use gas, oil and other fuel to operate. The agency denied a petition to remove the turbines from regulation.
• Men, uninsured people and those who live in the Midwest are among those more likely to have asthma that is connected to their work, a new study in the American Journal of Industrial Medicine finds. An estimated 896,000 U.S. workers have job-related asthma.
• People who store chemicals in their garages — such as lawn care products, pesticides and kerosene — have higher risks for amyotrophic lateral sclerosis, also known as ALS. Airflow into living spaces may explain the finding, researchers suggested in a study in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration.
The Watch is written by Michele Late, who has more than two decades of experience as a public health journalist.