Melioidosis: A Rare Bacterial Disease That Can Be Found in Your Aquariums

Sona Soban James
Monday, October 3, 2022

Diseases are often transmitted by sneezing or touching your utensils. But did you know that your home aquarium can be a safe refuge for one of the world's rarest bacterial diseases? That's what happened to a woman in Maryland, United States, who got it from her pet fish's aquarium.

This disease, known as melioidosis, is normally observed in tropical locations outside of the United States, and when cases do arise in the United States, they almost always occur in people who have travelled to other countries. The Maryland instance, which occurred in 2019, is remarkable in that the woman had never left the country. Her instance, according to the authors, is also the first in the world to be related to a home aquarium.

In a paper published in 1912, pathologist Alfred Whitmore and his assistant Krishnaswami first observed melioidosis among beggars and morphine addicts at an autopsy in Rangoon, present-day Myanmar. Melioidosis is an infectious disease caused by Burkholderia pseudomallei, shortened as B. pseudomallei. It is a gram-negative bacterium. Most persons who are exposed to the bacterium tend to remain asymptomatic. However, when symptoms are shown they can range from mild, such as fever and skin changes, to severe, such as pneumonia, abscesses, and septic shock, which can lead to death. "Chronic melioidosis" is when symptoms for more than two months. It occurs in approximately 10% of the patients.

Humans can be infected by contacting contaminated soil or water. Bacteria enter the body by wounds, inhalation, or ingestion. Person-to-person or animal-to-human transmission is extremely rare. The infection is always present in Southeast Asia, particularly in northeast Thailand and northern Australia. Melioidosis symptoms are similar to tuberculosis, and misdiagnosis is prevalent.

The chance of death is 10% in well-resourced settings where the disease may be recognized and treated early. The disease kills more than 40% of people in low-income countries.

Recurrence of symptoms after a time of disease remission ("recrudescence") might occur in persons who have received insufficient treatment. Recurrence can occur in patients who have finished therapy effectively due to recrudescence or new melioidosis infection. With improved therapy, the rate of recrudescence has dropped from 10% to 5%.

Diabetes mellitus, chronic kidney disease, and cancer can all worsen the long-term life and disability of persons who recover from infection. Encephalomyelitis is the most severe melioidosis complication. It can result in quadriparesis (muscle weakness in all four limbs), as well as partial flaccid paraparesis (muscle weakness of both legs), or foot drop.

In Australia, large-scale water chlorination has been beneficial in lowering B. pseudomallei in the water. Water should be boiled before consumption in middle- to low-income countries. For persons at risk of contracting melioidosis, water in high-income countries could be treated with ultraviolet radiation. Workers who are at high risk of coming into contact with the bacterium should wear protective gear (such as boots and gloves) while on the job. Residents of endemic areas should avoid direct contact with soil as well as outside exposure to heavy rain or dust clouds. In the case of drinking water, bottled or heated water is preferred. Like the old saying "prevention is better than cure", such practices will help in monitoring diseases, and hence can help society to protect their well- being.

Maryland woman catches rare tropical bacterial disease from her fish tank | Live Science
Melioidosis - Wikipedia

Sona Soban James
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