A disease that kills up to 70 percent of infected people has apparently been discovered for the first time in the United States.
According to a study by the Centers for Disease Control and Prevention (CDC), the bacteria that cause bush typhus were found in mites living in half of the North Carolina national parks surveyed.
It can be transmitted to humans through bites, causing symptoms such as rashes on the limbs and dark, scab-like sores on the skin. In severe cases, it can also impair lung and heart function, which can lead to death.
North Carolina State University scientists who led the research warned that further surveillance would be needed if the disease had spread to other states.
The map above shows where samples were collected in North Carolina. Darker colors indicate a higher proportion of mites transmitting the disease
Pictured above is the scab that can be caused by typhus (left) and a larva and adult mite that can carry the disease and transmit it to humans through a bite (right). The mites are depicted on a pinhead
No human cases of the disease have been identified in North Carolina, but insect-borne pathogens are on the rise nationwide.
Last month, the US announced that Florida and Texas had detected their first domestic malaria cases in two decades. And this month it was revealed that the mosquito-borne West Nile virus had reached new cities in Ohio and Connecticut.
There are also concerns about the spread of tick-borne diseases such as babesiosis, which kills one in five infected people, and could spread further north.
dr Kaiying Chen, an entomologist at North Carolina State University who led the study, told DailyMail.com, “This is the first time.” [scrub typhus] has been demonstrated in the free-living chigger [mite] in the USA.’
Native to an area called the Tsutsugamushi Triangle — named for the bacteria that causes the disease — bush typhus stretches from Pakistan to far east Russia and Australia, where there are a million cases each year.
It is estimated that up to 60,000 people could die from the disease each year, with death rates being kept low by the rapid administration of treatments such as the antibiotic doxycycline. This prevents the disease from escalating to later stages where it is more deadly.
But more recently it has been appearing in other areas, including the Middle East, southern Chile and Africa, prompting researchers to look for it in the United States.
Also known as bush typhus, it is caused by infection with the bacterium Orientia tsutsugamushi, which can be transmitted by mites.
A reddish or pink lesion appears at the site of the mite bite about 10 to 12 days after infection.
The patient may also experience headaches, fever, chills, and muscle aches, and there may be a sore, punched-out skin on the skin.
About a week later, a pink rash may also appear on the skin around the abdomen, which can then spread to the arms and legs.
Left untreated, the disease can also lead to abnormalities in the heart, lungs, and blood—which can lead to death.
Treatment includes doses of the antibiotic doxycycline to kill the bacteria causing the infection.
Scientists at the University of Texas say between 30 and 70 percent of patients die if they don’t receive treatment.
For the study, published today in the Morbidity and Mortality Weekly Reports (MMWR), scientists examined mite populations in ten North Carolina national parks.
The mites were collected by placing a tile, typically one meter by one meter, on the ground and examining the area within for arthropods.
Ten mites were collected from nine locations, while only five mites were collected from one location.
All mites were then tested to see if they were carriers of the bacteria that cause bush typhus.
Tests found nine out of ten mites at Lumber River State Park were infected with bush typhus.
Eight in 10 in the Kerr Lake State Recreation Area carried the bacteria that caused the disease, and one in 10 in the Falls Lake State Recreation Area and Morrow Mountain State Park.
One of the five residents at Merchant Millpond State Park was also infected.
dr Chen and her team said in the newspaper, “This result is…significant because it indicates…the circulation of….” [scrub typhus] in chiggers [mites] collected in the continental United States.’
It wasn’t clear how the disease got to the US, but it may be the case Mites that transmit the disease entered the country by air or imported by ship.
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