Endemic Melioidosis in the United States

In July 2022, CDC scientists discovered that Burkholderia pseudomallei, the bacterium that causes the rare disease melioidosis, is now locally endemic to the southern continental United States. Melioidosis is significant: Globally, it's fatal in up to half of people infected, and as a nationally notifiable disease in the United States, melioidosis should always be reported to state health departments and CDC. The finding of B pseudomallei in the southern United States followed a melioidosis diagnosis in a person who lived in very close geographic proximity to someone else who had been diagnosed with melioidosis two years prior — both residents of the same Mississippi county, along the Gulf Coast of the southern United States. Neither had recently traveled outside the United States. Environmental sampling of surface water and soil revealed the presence of B pseudomallei on the property of one of these patients. With a third case identified in January 2023, it's critical that healthcare providers and laboratorians are aware of the potential for additional cases of this newly endemic disease and know what to look out for.

It is not known how long the bacterium has been in the environment and where else it might be found in the United States, but CDC scientists were not shocked by this discovery because the environmental conditions found in the Gulf Coast states are conducive to the growth of B pseudomallei. This bacterium has historically been found in tropical and subtropical areas such as South and Southeast Asia, northern Australia, and parts of Central and South America and Puerto Rico, and most cases identified in the United States — an average of 12 per year — have been linked to travel to these areas.

Melioidosis is caused by direct contact (through breaks in the skin, ingestion, or inhalation) with soil or water contaminated with the bacterium B pseudomallei. Cases of domestically acquired melioidosis also have been linked to contaminated commercial products imported from disease-endemic countries. This recently occurred in 2021 when four cases distributed across four states were linked to an imported contaminated aromatherapy spray. Melioidosis has a wide range of nonspecific symptoms, such as fever, joint pain, and headaches. It also can cause pneumonia, abscess formation, or blood infections.

Now that we know the bacteria is found in the continental United States, it is even more important for healthcare providers to be informed about melioidosis and to consider it when conducting diagnostics, particularly among people living in Gulf Coast states.

Recommendations for Clinicians and Public Health Practitioners

CDC encourages clinicians in the Gulf Coast region of the southern United States and throughout the country to learn about melioidosis and to be aware of the potential for more non-travel cases as CDC and state partners continue investigating the geographic spread of B pseudomallei.
Consider melioidosis in patients with a compatible illness who:
- live in, or have traveled to, the Gulf Coast region of the southern United States, and
- have risk factors for melioidosis such as diabetes, excessive alcohol use, or chronic lung disease, and
- report any occupational or recreational activities involving the handling of soil, like gardening, agriculture, or construction, or
- have contact with fresh water, such as swimming or fishing in lakes, ponds, or rivers.
When ordering specimen cultures to diagnose melioidosis, advise the laboratory that cultures may grow B pseudomallei and that appropriate laboratory safety precautions should be observed by the laboratory personnel. Common clinical laboratory methods may misidentify B pseudomallei. Consultation with your local or state health department is strongly recommended when melioidosis is suspected.
Culture of B pseudomallei from any clinical specimen is considered diagnostic for melioidosis. Recommended specimens for culture are guided by the clinical syndrome and might include blood, sputum, urine, purulent exudate (from skin or internal abscesses), synovial fluid, peritoneal fluid, pericardial fluid, or cerebrospinal fluid. Throat and rectal swabs can also be collected.
Consultation with infectious disease specialists is strongly recommended. Treat melioidosis with IV antibiotics (eg, ceftazidime, meropenem) for at least 2 weeks. Depending on the response to therapy, IV treatment may be extended for up to 8 weeks. Intravenous treatment should be followed by oral trimethoprim-sulfamethoxazole (TMP/SMX) for 3-6 months to prevent relapse. Amoxicillin/clavulanic acid can be used in individuals who are unable to receive TMP/SMX.

Given the very small number of cases of melioidosis identified historically in the United States, CDC believes that the risk for melioidosis for the general population continues to be very low. However, any person who develops a compatible illness — particularly people who reside in or have traveled to the Gulf Coast region of the southern United States or areas where B pseudomallei has historically been endemic — should seek immediate care and ask their healthcare provider about melioidosis.

For more information, visit CDC's melioidosis website.

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