The Viriginia woman who swatted a fly off her 77-year-old friend’s shoulder just moments before she collapsed and later died said she’s convinced it was a "Kissing Bug" that triggered her fatal reaction.

“No doubt in my mind that’s what it was,” Karen Hudgins told the Danville Register & Bee.

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Hudgins had been walking with her friend Evelyn Wooten in Riverwalk Trail in Danville, Va., on July 2 when tragedy struck.

“We were walking and she said, ‘Karen, get that bug off of me,'” Hudgins told the news outlet.

Just 10 minutes later, Hudgins said Wooten said she couldn’t breathe and that she looked pale before collapsing.

“The last thing she said was ‘911,’” Hudgins said. “She started welling up and turning blue, her lips, arms everything.”

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According to the news outlet, Wooten never regained consciousness and was declared brain dead the next day. Her son said doctors told the family it was an allergic reaction to a bug bite.

Triatomine bugs, which are also called kissing bugs, can be found in cracks and holes in houses, or outside beneath porches, between rocky structures, under cement, in rock, wood, brush piles or bark, in rodent nests or animal burrows, in outdoor dog houses or in chicken coops. According to the Centers for Disease Control and Prevention (CDC), they are typically found in the southern parts of the U.S., as well as Mexico, Central American and South America.

The saliva from triatomine bugs can trigger an allergic reaction in some people, which can include severe redness, itching, swelling, welts, hives or in rare cases anaphylactic shock. The CDC advises people who have experienced anaphylactic shock previously to ask a doctor what medication to use in the event of a bite.

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The agency notes that not all triatomines carry the T. cruzi parasite, which causes Chagas disease. Even the bugs that cause an allergic reaction may not carry the parasite. If left untreated, Chagas infection can be lifelong. Complications of chronic Chagas disease can include heart rhythm abnormalities, dilated heart, or dilated esophagus or colon.

“It was very unexpected,” Mark Wooten, the woman’s son, told the Danville Register & Bee.