- Everyone knows that ticks spread Lyme disease. But hepatitis
C virus?
-
- Scientists at the American Red Cross say they've made
a circumstantial case for a tick passing the infection to a Connecticut
woman who had no other obvious means of contracting the liver-damaging
malady.
-
- "Ticks obviously ingest a fair amount of host blood
and re-inject blood into the next animal or person they bite. They at least
could act like little syringes," says Dr. Ritchard Cable, medical
director for the Red Cross's blood services center in Farmington, Conn.
He and his colleagues describe the case in a research letter in tomorrow's
issue of The New England Journal of Medicine.
-
- Cable admits the connection could be coincidence. He
has seen no other evidence of ticks ferrying hepatitis C from one person
to another, nor to a person from an infected animal -- assuming that animals
can contract the virus. What's more, it's not even clear the microbe can
survive in ticks.
-
- Still, they have no better explanation for how the woman
picked up the disease. She denies being infected on the job or having any
high-risk lifestyle habits, such as multiple sex partners or drug use.
-
- The woman, a health-care worker and regular blood donor,
was participating in a 1999 Red Cross study of a disease called babesiosis
that's transmitted by deer ticks. Blood she gave in July 1999 tested positive
for that disease, but not for hepatitis C.
-
-
- Yet when the woman gave blood five months later, hepatitis
C appeared, a highly unusual event in regular donors. An August blood sample
drawn as part of the study also turned up genetic evidence of the virus
upon re-examination.
-
- When doctors spoke to the woman, Cable says, she revealed
that she'd been ill in September with symptoms that were consistent with
hepatitis C, including fatigue, stomach cramps, loss of appetite and dark
urine. Intriguingly, she seemed to have acquired the infection during roughly
the same window of time that she also picked up babesiosis, he says.
-
- Ticks do transmit at least one virus related to hepatitis
C, causing tick-borne encephalitis, says Tom Schwan, an expert on the creatures
at the National Institutes of Health's Rocky Mountain Laboratories in Hamilton,
Mont. In Africa, ticks on rare occasions shuttle a disease called relapsing
fever from person to person.
-
- Even so, Schwan says catching hepatitis C from a tick
bite would be "an extremely rare event that assumes many things"
-- including that the parasites are suitable hosts for the virus. "I
would be very cautious" about concluding that the Connecticut case
isn't one of mistaken infectivity, he adds.
-
- Hepatitis C, which can lead to fatal liver damage, affects
nearly 4 million Americans. The disease typically causes no symptoms for
years, earning it the nickname the "silent killer."
-
- Most infections occur in drug users sharing tainted needles.
Screening of the blood supply has driven the rate of transfusion transmission,
once a major problem, to less than one case per million units, according
to the U.S. Centers for Disease Control and Prevention.
-
- What To Do
-
- To learn more about hepatitis C, try the U.S. Centers
for Disease Control and Prevention. For more on the nation's blood supply,
try the American Red Cross.
-
- http://story.news.yahoo.com/news? tmpl=story&u=/hsn/20021120/hl_hsn/can_ticks_spread_hepatitis_c_virus_
|
