Contaminated water, soil tied to rare tropical disease melioidosis in 3 men in same Mississippi county

News brief

Looking for meloidosis — Carla Boutwell / Mississippi State Department of Health

Over a 3-year period, three men in Mississippi were infected with a newly identified strain of the bacterium that causes melioidosis after contact with contaminated water and soil, the first known cases of environmental transmission in the continental United States, the New England Journal of Medicine reports today.

Caused by Burkholderia pseudomallei, melioidosis is a potentially life-threatening disease typically spread through inhalation, ingestion, or skin contact with the water or soil of tropical and subtropical regions, where it is endemic.

"Melioidosis is rare in the United States; the Centers for Disease Control and Prevention (CDC) has received reports of approximately 12 cases each year that were determined to have been predominately associated with travel to regions in which melioidosis was endemic," the CDC-led investigative team wrote.

The CDC had reported the first two cases and an earlier outbreak traced to an aromatherapy room spray in 2022.

Melioidosis may be endemic in region

The men, who lived in the same Gulf Coast county but didn't know each other, sought care at a hospital with conditions such as acute respiratory distress, multi-organ failure, pneumonia, and sepsis and were diagnosed as having melioidosis in 2020, 2022, and 2023, respectively.

Blood cultures revealed the same Western Hemisphere B pseudomallei strain in all three men, who reported symptoms such as fever and shortness of breath. The men reported no travel to melioidosis-endemic areas. Two men recovered after receiving antibiotics, and one is recovering.

Clinicians should consider melioidosis in patients with a compatible illness who reside in or have traveled to the Gulf Coast region of the southern United States or to areas where B. pseudomallei has historically been endemic.

The investigators tested 168 environmental samples from areas where the two patients lived, worked, and fished (eg, a tugboat, plants, dead fish), discovering B pseudomallei in three water and soil samples from one man's property.

"These findings indicate that melioidosis may be endemic to the Mississippi Gulf Coast region," they wrote. "Clinicians should consider melioidosis in patients with a compatible illness who reside in or have traveled to the Gulf Coast region of the southern United States or to areas where B. pseudomallei has historically been endemic."

FDA grants priority review for adult pneumococcal conjugate vaccine

News brief

Chris Dall, MA

Merck announced this week that the US Food and Drug Administration (FDA) has granted the company priority review of its application for approval of an investigational pneumococcal conjugate vaccine for adults.

Merck's 21-valent (21-strain) pneumococcal conjugate vaccine, V116, is designed to help prevent pneumococcal disease and pneumococcal pneumonia in adults, covering serotypes that are responsible for 83% of invasive pneumococcal disease in people 65 years of age and older. It includes eight unique Streptococcus pneumoniae serotypes not covered by currently licensed pneumococcal vaccines.

Targeting strains that target adults

"If approved, V116 would be the first pneumococcal conjugate vaccine specifically designed to address the serotypes that cause most adult invasive pneumococcal disease," said Eliav Barr, MD, senior vice president, chief medical officer, and head of global clinical development at Merck Research Laboratories, in a company press release. "We look forward to discussing the data that support our filing with the FDA and are working with urgency to bring this potential new preventative measure to adult patients.”

The Biologics License Application is based on the results of multiple phase 3 trials that evaluated V116 in both vaccine-naïve and vaccine-experienced adults. In the STRIDE-3 trial, V116 elicited non-inferior immune responses to PCV20 (pneumococcal 20-valent conjugate vaccine) for all 10 serotypes covered by both vaccines, and superior immune responses for 10 of 11 serotypes included in V116 but not covered by PCV20.

The FDA has set a target action date of June 17, 2024.

If approved, V116 would be the first pneumococcal conjugate vaccine specifically designed to address the serotypes that cause most adult invasive pneumococcal disease.

WHO prequalifies second malaria vaccine

News brief

Lisa Schnirring

The World Health Organization (WHO) today announced it has prequalified a second malaria vaccine, R21/Matrix-M, which clears the way for countries and groups to buy the vaccine for a broader rollout after the WHO recommended the vaccine in early October.

malaria vaccination — UK DFID / Flickr cc

In its statement today, the WHO said prequalification means larger access to vaccines as a tool to prevent malaria in children, through procurement by UNICEF and funding to support deployment from Gavi, the Vaccine Alliance.

The WHO prequalified the first vaccine, RTS,S/AS01, in July 2022. Clinical trials have shown that both vaccines are safe and effective for preventing malaria in children, who have shouldered a heavy burden from the disease. Health groups estimate that the disease is responsible for 500,000 deaths in children each year, mainly in Africa.

Developed by Oxford University and made by the Serum Institute of India (SII), the arrival of R21/Matrix-M will expand supply. Demand has been high, but earlier doses weren't plentiful enough to benefit all children living in areas at greatest risk. SII has said that it can make 200 million doses each year.

15% of deer on depopulated Wisconsin farm had CWD, authorities report

News brief

Mary Van Beusekom

Twenty-three of 172 deer (13%) killed after discovery of chronic wasting disease (CWD) on a Dodge County, Wisconsin, deer farm in May 2023 have tested positive for the disease, the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) said in a news release yesterday.

With another three CWD disease detections in deer who died before the herd was depopulated, the total number of cases comes to 26 (15%).

Farm quarantined in May

In May, DATCP quarantined the farm after a 9-year-old doe tested positive for CWD. After the US Department of Agriculture Wildlife Services (USDA) culled the herd, it sent samples to the USDA National Veterinary Services Laboratory in Ames, Iowa, for testing.

During the next 5 years, the farm won't be able to hold cervids—members of the deer family—and must maintain fences and allow routine inspections. The farm owner will be compensated with federal indemnity funds for the loss, said the DATCP, which regulates deer farms for registration, recordkeeping, disease testing, movement, and permit requirements.

Found in cervids in 32 US states, 4 Canadian provinces, and South Korea, Finland, Sweden, and Norway, CWD is a fatal neurodegenerative disease caused by infectious misfolded proteins called prions. Though no human cases have been found, health officials urge people to avoid eating the meat of infected animals and to take precautions when field-dressing or butchering cervids.