CDC Statement on Investigation Into Multi-State Melioidosis Outbreak

Credit CDC PHIL

#16,117

Two days ago (see CDC HAN Update: 4th Case of Non-Travel Related Melioidosis Reported - Georgia) - and for the second time in just over a month - we looked at a CDC HAN advisory on a multi-state outbreak of a very rare bacterial infection  not normally seen in the United States. 

None of these 4 patients (2 of which have died) had traveled outside of the country, and no epidemiological links between them have been established.  Genomic analysis of their infections suggest, however, that all 4 share a common source.

While this isn't the first time we've seen this type of occurrence (see 2020's EID Journal Melioidosis in a Resident of Texas with No Recent Travel History, United States), finding 4 seemingly unrelated cases across 4 states is a concern. 

Late on Monday the CDC issued the following statement on their ongoing investigation. 

Statement on Melioidosis Cases
Media Statement

For Immediate Release: Monday, August 9, 2021
Contact: Media Relations
(404) 639-3286

The Centers for Disease Control and Prevention (CDC) has confirmed a new fatal case of the rare disease melioidosis in Georgia that is linked to three previous cases in different states. The cases have included adults and children. Two of the four patients had no known risk factors for melioidosis; two died.

Whole genome sequencing at CDC shows the bacterial strains that sickened the patients – one each in Georgia, Kansas, Texas and Minnesota – closely match each other, suggesting there is a common source for these cases. They appear most closely related to strains found in Asia, particularly South Asia, even though none of the patients had traveled internationally.

CDC has collected and tested more than 100 samples from products, soil, and water in and around the patients’ homes. No samples have yet been positive for the bacteria Burkholderia pseudomallei, which causes melioidosis. Currently, CDC believes the most likely cause is an imported product (such as a food or drink, personal care or cleaning products or medicine) or an ingredient in one of those types of products. The bacteria normally lives in moist soil and water. However, in rare cases, it has also been found to contaminate wet or moist products in the areas where the bacteria are common.

Identifying a single source of infection my be difficult because:

• The patients are spread apart by geography and time their illness began.
• Each could have been exposed to potentially hundreds of products before they became ill.
• Unlike the germs that cause most foodborne outbreaks, the bacteria responsible for melioidosis can take two to three weeks to make someone sick. This expands the window of time that investigators need to explore and means people may be less likely to remember everything they were exposed to before becoming ill.

CDC is asking clinicians to watch for any acute bacterial infection that doesn’t respond to normal antibiotics and consider melioidosis – regardless of whether the patient traveled outside the United States. CDC also urges clinicians not to rule out melioidosis as a possible diagnosis in children and those who were previously healthy and without known risk factors for melioidosis.

Although healthy people may get melioidosis, underlying medical conditions may increase the risk of disease. The major risk factors are diabetes, liver or kidney disease, chronic lung disease, cancer or another condition that weakens the immune system. Most children who get melioidosis do not have risk factors. People experiencing cough, chest pain, high fever, headache or unexplained weight loss should see their doctor.

For more information on melioidosis, please visit https://www.cdc.gov/melioidosis/index.html.

Although commonly found in the environment in the tropics, and particularly in Southeast Asia Burkholderia pseudomallei - the causative agent of Melioidosis - is a particularly nasty pathogen. Enough so that is is considered to have at least some bioterrorism applications.

From the CDC website.

Bioterrorism

Melioidosis is a disease caused by germs that occur naturally in certain parts of the world, such as Southeast Asia and northern Australia. The only places these germs, called Burkholderia pseudomallei, occur naturally in the United States is Puerto Rico and U.S. Virgin Islands. One reason public health authorities study the disease is because it is possible that the germs that cause melioidosis might be used in a biological attack. A biological attack is the intentional release of germs that can sicken or kill people, livestock, or crops. 

That said, there are no indications that these infections represent an intentional release, and it is most likely the result of accidental contamination of an imported product.