Dangerous Kisses

Lessons of the Kissing Bug’s Deadly Gift
Lawrence K Altman
April 12, 2005
NY Times

Chagas disease, which exists only in the Americas, has infected approximately 16 million people and causes about 50,000 deaths a year. It is a parasitic infection transmitted through the kissing bug (also known as the reduviid bug or the triatomine bug). The insect lives in cracks and crevices in poor housing where it bites people on the face, often while they are sleeping. It can also be transmitted via food contamination, blood transfusions, organ transplants, and from mother to child at birth.

The initial symptoms of Chagas disease are usually mild or nonexistent, so they are either construed as something else or simply go unnoticed. It usually takes decades for the disease to cause death by slowly damaging heart muscle, the esophagus, and colon, and by that time drugs cannot reverse the damage. The exact mechanism of the disease are still under investigation, although scientists have several hypotheses, including that it might be an autoimmune disease, or that the parasite causes an overly aggressive anti- parasite inflammatory response due to chronic presence of the parasite, as described in a later article.

However, in this particular outbreak described by the article in Brazil, symptoms did present themselves within a few days of the outbreak, which was apparently transmitted orally through contaminated sugar juice. The juice was pulled off the market and people who were anywhere in southern Brazil at the time were advised to get medical checkups if they drank sugar cane juice. The symptoms included fever, headache, muscle aches, vomiting, and a rash. Many people also experienced swollen lymph glands and spleen, abdominal pain, intestinal bleeding, jaundice, and encephalitis.

There are 2 drugs currently available—Benzonidazol, made by Roche, and Nifurtimox, made by Bayer. These drugs seem to be effective for treating Chagas disease in its early stages. Doctors are not sure why symptoms in this outbreak are more immediate and severe. One theory is more parasites entered the body through food than would have found their way to blood from a bite. Another theory is it might be an usually virulent strain of the Chagas parasite.
More research is needed to see how the bugs were deposited in the sugar cane, how long the parasite can survive in feces outside the kissing bug, as well as strategies to prevent oral transmission.

http://www.nytimes.com/2005/04/12/health/12docs.html