Although your chances of getting a serious case of leptospirosis disease are still statistically low, you may be more at risk for developing its flu-like symptoms than you know.
A study published in 2022, but not aired broadly before now, concluded that the bacteria that causes the disease is widely circulating in the territory via rats and mice, the most common carriers of the disease to humans.
Researchers collected and assessed 112 mice (Mus musculus) and 28 common rats (Rattus rattus) from throughout the territory, and lab tests showed that 64 of the 140 rodents, or 45 percent, carried the leptospira bacteria.
Although it was previously known to infect some animals, the presence of the disease in people was first confirmed in the Virgin Islands in October 2017, a month after Hurricanes Irma and Maria devasted the territory when it was documented in several residents.
Local Health officials have been on the lookout for it ever since. In 2019 Health conducted a survey of home cisterns, doing lab tests on unfiltered water. Among the findings was that three of 47 cisterns that were tested (or six percent) had leptospira bacteria in the water.
A global phenomenon, leptospirosis is a zoonosis disease, meaning it affects both animals and humans. It is spread by contact with water or soil that has been contaminated with urine from an infected animal, or with direct contact with the infected animal. Outbreaks in an area often follow on the heels of heavy rains and flooding.
Typical symptoms include high fever, headache, chills, muscle aches, vomiting, diarrhea, abdominal pain, rash, jaundice, and red eyes. Symptoms may be mild -or even non-existent – and are often confused with other illnesses, such as the common flu.
A serious case, however, can be life-threatening. An estimated one percent of cases can develop into Weil’s syndrome, which can cause internal bleeding and kidney damage, according to the Cleveland Clinic website.
About one million of the world’s 86 billion people get leptospirosis every year, and about 60,000 people die from it, according to information on the site.
Those numbers pale in contrast to many other diseases. For instance, the Center of Disease Control and Prevention says about 48 million people in the U.S. alone get some sort of food poisoning each year. And the World Health Organization says malaria kills about 558,000 of the world’s population each year, a figure nearly 10 times that of the deaths from leptospirosis.
However, concerns about it are growing.
“Leptospirosis, the most widespread zoonosis in the world, is an emerging public health problem,” according to the National Institutes of Health, which also says “rats serve as the major carriers in most human leptospirosis.” While almost any mammal may be infected, rodents can carry the bacteria without getting sick from it.
The prevalence of the bacteria in VI rats and mice, per the 2022 report, is in line with its presence elsewhere, according to local Health experts.
Territorial Epidemiologist Esther Ellis, and Epidemic Intelligence Service Officer and veterinarian Springer Browne, both of whom worked on the report, responded jointly via email to questions about it from the Source.
“Across the world, approximately half of most rodents can carry and shed leptospirosis at any given time,” they said, adding that a 2019 study conducted in neighboring Puerto Rico found the leptospira bacteria in 59 percent of house mice and 34 percent of tree rats.
It’s hard to say how long the disease may have been circulating in the Virgin Islands, or in any given area.
In 1992, there was a study conducted in the territory on some domestic animals that found that 26 percent of goats and 32 percent of sheep had been exposed to leptospira bacteria. The study didn’t test for “shedding” or transmission, according to the Health experts. It only confirmed that the animals had produced blood antibodies, a response to being exposed to the bacteria.
“The disease was first described in 1886 in Germany,” they said, “and is suspected to be linked to the spread of the Norway rat across Eurasia and Europe… It was first reported in Puerto Rico in 1918, Trinidad in 1931, Barbados in 1939, and Jamaica in 1953.”
There is no vaccine against leptospirosis. And currently, the officials said, there are no plans locally to attempt to eradicate rats and mice.
However, there are some commonsense measures people can take to protect themselves.
“The risk of acquiring leptospirosis can be greatly reduced by not swimming or wading in water that might be contaminated with animal urine, or eliminating contact with potentially infected animals,” according to Ellis and Browne. It’s also important to filter and treat cistern water before it gets to household faucets such as showers or the kitchen sink because the bacteria can enter a person through any orifices including eyes, ears, and mouth.
Additionally, “protective clothing or footwear should be worn by those exposed to contaminated water or soil because of their job or recreational activities,” they said.
Leptospirosis can easily be missed, not only because its symptoms are often mild and can be mistaken for other illnesses, but also because there can be a lag time between exposure and manifestation. It is also possible to have the disease and have no symptoms.
For people who are not asymptomatic, it may be anytime between two days and four weeks after they are exposed to the bacteria before they become sick. But then fever and other symptoms hit abruptly rather than gradually.
Typically, the illness lasts from a few days to three weeks or longer. “Without treatment, recovery may take several months,” Health experts said.
Some patients recover for a time and then get sick again. “If a second phase occurs, it is more severe,” they said. It can lead to kidney or liver failure or meningitis.
Antibiotics, such as doxycycline or penicillin, are used to treat leptospirosis and they should be started early on, according to Health officials.
“Persons with symptoms suggestive of leptospirosis should contact a health care provider,” they advised.
The report, “Assessing rodents as carriers of pathogenic Leptospira species in the US Virgin Islands and their risk to animal and public health” was published by Scientific Reports last year. The lead author, Camila Hammond, is affiliated with the National Veterinary Services Laboratories. There were 23 co-authors, including Browne and Ellis.
