Behind the Scenes of an Investigation with Julia Petras (EIS 2021)

Summary

The script recounts a thrilling investigation into the unexpected appearance of melioidosis, a rare tropical disease, in the US. Caused by Burkholderia pseudomallei, it was traced to an aromatherapy spray and a pet raccoon, leading to a nationwide recall. Further probes in Mississippi identified the bacterium in local soil and water, marking the first US environmental isolation. The narrative underscores the importance of collaborative, boots-on-the-ground epidemiology and the value of pursuing all leads, no matter how unlikely.

Takeaways

• 🌿 Melioidosis is a rare tropical disease caused by the bacterium Burkholderia pseudomallei, typically found in Southeast Asia, northern Australia, and Central America.
• 🔍 The speaker's team investigated unexpected domestic outbreaks of melioidosis in the United States, involving patients with no travel history.
• 🚨 Burkholderia pseudomallei is a tier one select agent that can be weaponized, prompting involvement from the FBI in the investigation.
• 🏠 The initial hypothesis was that the source of the disease was an imported product from South Asia.
• 🌬️ An aromatherapy spray was identified as the source of the outbreak, with a strain genetically identical to the infections found in four patients.
• 🦝 A pet raccoon in Texas was suspected of contracting melioidosis after knocking over the implicated aromatherapy spray and later died.
• 🔬 The team collaborated with the EPA to exhume the raccoon, which tested positive for Burkholderia pseudomallei.
• 📚 The case was reported in the New England Journal of Medicine and MMWR, highlighting the importance of the discovery.
• 🌊 A subsequent case in Mississippi led to the discovery that the bacterium could be endemic to parts of the southern United States.
• 🏡 Environmental samples from a subdivision in Mississippi tested positive for Burkholderia pseudomallei, marking the first time it was isolated in the continental U.S. environment.
• 👥 The investigations required a collaborative effort from various health departments, epidemiologists, and laboratory scientists.

Q & A

What is melioidosis?

Melioidosis is a rare tropical disease caused by the bacterium Burkholderia pseudomallei, which is typically found in soil and water in tropical and subtropical regions.

Why was the FBI interested in the melioidosis outbreak?

The FBI was interested because Burkholderia pseudomallei is a tier one select agent that can be aerosolized and potentially used as a biological weapon.

What was unusual about the patients infected with melioidosis mentioned in the script?

The unusual aspect was that four patients, who did not know each other and lived in different states, were infected by the same clonal strain of Burkholderia pseudomallei without having traveled outside the United States.

What was the initial hypothesis regarding the source of the melioidosis outbreak?

The initial hypothesis was that the source was an imported product from South Asia.

What product was eventually linked to the outbreak?

A Better Homes and Gardens aromatherapy spray collected from a patient's home was found to be positive for Burkholderia pseudomallei.

What was the unexpected finding involving a pet raccoon?

The pet raccoon of a Texas patient knocked over the implicated aromatherapy spray, walked over its contents, and later died of acute neurological symptoms, which were suspected to be caused by melioidosis.

Why was the raccoon's death significant?

If the raccoon died of melioidosis and was buried in the yard, it could potentially contaminate the local environment, leading to concerns about the establishment of this rare bacterium in Texas.

What actions were taken after discovering the raccoon's death?

The team, including the speaker and a colleague, put on hazmat suits, dug up the raccoon, and decontaminated the burial site. The raccoon tested positive for Burkholderia pseudomallei.

What was the second outbreak of melioidosis that occurred in Mississippi?

The second outbreak involved another confirmed case of melioidosis in Mississippi with no travel history outside the US, infected by a distinctly different strain of Burkholderia pseudomallei of Western Hemisphere origin.

What was the significance of finding Burkholderia pseudomallei in the environment in Mississippi?

It was the first time the bacterium was isolated in the environment in the continental United States, indicating a newly endemic disease.

What was the key to solving the investigations?

The key was a team effort, persistence, and a boots-on-the-ground approach, including collaboration with state and local health departments, epidemiologists, laboratory scientists, and others.