There has been a considerable increase in the potentially deadly tick-borne disease babesiosis in the United States, according to new research.
Among tick-borne pathogens, babesia is considered to be a serious threat to human beings. It can infect and destroy red blood cells, a condition called babesiosis. Around 0.5 percent of infected individuals are estimated to die from the disease.
Among immunocompromised individuals and the elderly, the mortality rate can go up to one in five.
In Vermont, case numbers jumped from 2 to 34 between 2011 and 2019, the report said. In Maine, this rose from 9 to 138. And in New Hampshire, cases jumped from 13 to 63.
“During 2011–2019, a total of 16,456 cases of babesiosis were reported to CDC by 37 states, including 16,174 (98.2 percent) reported from the 10 states included in this analysis,” the report said.
“New York reported the largest number of cases (4,738 total; average = 526.4 per year), followed by Massachusetts (4,136; 459.6), and Connecticut (2,200; 244.4). The lowest numbers of cases were reported in Vermont (114; 12.7) and New Hampshire (340; 37.8).”
Babesiosis can be a “severe, life-threatening disease,” particularly among people who do not have a spleen, have a weak immune system, have other serious health conditions like kidney or liver disease, or are elderly, the CDC said.
The Infection
According to an April 13 news release from the University of California Riverside, “all cases of human babesiosis reported in the United States have been linked to either Babesia microti, B. duncani, or a B. divergens-like species.”“In older and immunocompromised people, if B. duncani is left unattended, babesiosis could worsen and lead to death. Once the pathogen enters the body and red blood cells start to get destroyed, fever, headache, and nausea can follow.”
“People who get bitten by the ticks often don’t feel the bite, which complicates diagnosis. Skin manifestations of babesiosis are rare … and difficult to separate from Lyme disease.”
In the United States, babesiosis caused by B. duncani is an “emerging infectious disease” that is often undetected since healthy individuals with the disease do not usually show any symptoms.
Despite its highly virulent properties, very little is known about the biology, mechanism of virulence, and evolution of B. duncani. Existing recommended treatments for babesiosis against B. duncani are also “largely ineffective,” the release states. Diagnostics are usually developed for B. microti.
Therapies
Karine Le Roch, a professor of molecular, cell, and systems biology at UC Riverside, who co-led the study, pointed out that the parasite has evolved into new classes of multigene families, allowing it to avoid the immune response of the host.According to Le Roch, the study not only identifies the molecular mechanism that will most likely lead to the parasite’s virulence and pathology but also opens up opportunities for the development of more effective therapies.
“By mining the genome and developing in vitro drug efficacy studies, we identified excellent inhibitors of the development of this parasite—a pipeline of small molecules, such as pyrimethamine, that could be developed as effective therapies for treating and better managing human babesiosis,” Le Roch said.
“Far more scientific and medical attention has been paid to B. microti. The genome structure of B. duncani, a neglected species until now, will provide scientists with important insights into the biology, evolution, and drug susceptibility of the pathogen.”