Via the University of Vermont: With climate change, US could face risk from Chagas disease. Excerpt:
In the spring of 1835, Charles Darwin was bitten in Argentina by a “great wingless black bug,” he wrote in his diary.
“It is most disgusting to feel soft wingless insects, about an inch long, crawling over one's body,” Darwin wrote, “before sucking they are quite thin, but afterwards round & bloated with blood.”
In all likelihood, Darwin’s nighttime visitor was a member of Reduviid family of insects — the so-called kissing bugs because of their habit of biting people around the mouth while they sleep.
From this attack, some infectious disease experts have speculated, the famed naturalist might have contracted Chagas disease, a parasite-borne illness carried by kissing bugs, that today afflicts millions of people in Central and South America. Darwin’s bite may have led, ultimately, to his death from heart problems.
This hypothesis has been contested for decades, but if Darwin had experienced this bug attack in the United States, no one would have made such a speculation, since Chagas disease is almost unheard of in the U.S.
That could change, new research shows.
Lori Stevens, a biologist at the University of Vermont, and her colleagues, found that 38 percent of the kissing bugs they collected in Arizona and California contained human blood.
This upends the previous understanding of insect experts and doctors that the eleven species of kissing bugs that occur in the US don’t regularly feed on people.
“This finding was totally unexpected,” says Dr. Stephen Klotz, head of the infectious diseases department at the University of Arizona medical school and a co-author on the study.
And more than 50 percent of the bugs the research team collected also carried Trypanosoma cruzi, the parasite that causes Chagas disease.
Their study is reported in the March 14 online edition of the journal Emerging Infectious Diseases.
“The basic message is that the bug is out there, and it’s feeding on humans, and carries the parasite,” says Stevens, “so there may be greater potential for humans to have the disease in the United States than previously thought.”
