Rare Human Case of Insect-Transmitted Parasite Discovered

Newswise — Dr. Patricia Dorn, professor of biology at Loyola University New Orleans has discovered the first human case of insect-transmitted Chagas parasite in Louisiana and sixth ever in the United States.

The discovery, made in collaboration with Dawn Wesson, Ph.D., of Tulane University Health Sciences Center and Loyola undergraduate student Leon Perniciar, was made in July 2006 in a rural area of New Orleans.

The Chegas parasite is carried by Reduviid bugs, commonly called cone-nosed bugs or kissing bugs. Over a dozen species of the insect are found in the United States, mostly in the south between California and Florida and in the east north toward Maryland.

"People in the United States rarely contract the Chagas parasite from kissing bugs," says Dorn. "Previously there had only been five reported cases. Three of these cases occurred in Texas infants, two in 1955 and the other in 1983. The fourth case occurred in a 56-year-old California woman in 1982. The fifth case occurred in rural Tennessee in 1998 in an 18-month-old child. The bug was found in the child's crib, and the infection was detected and treated during the acute stage. Another case of an infant in Texas is currently under investigation."

This new discovery was made after a resident brought insects to the attention of a pest control operator who identified them as kissing bugs. After researching the bug on the Internet, the resident realized the potential for Chagas transmission. Because of Dorn's expertise in this field, she was contacted to administer the test for the parasite and further investigate this situation. Both residents were tested at Loyola and the Centers for Disease Control and one resident tested positive for the exposure to the Chagas parasite. Many insects have been collected in the house and the nearby building and studies carried out by Dr. Dorn and her students over the last several months indicate that more than half of the insects tested carry the Chagas parasite.

The discovery is not considered a widespread public health concern.

"We don't tend to live in houses that provide good habitat for the kissing bugs and that the insects can get into at night, when they feed," she says. The finding in Louisiana was in a very open house with numerous points of entry.

Chegas disease, the leading cause of heart disease in Latin America, rarely shows symptoms following infection; in fact, symptoms usually take 10 to 20 years to develop. Fortunately, only 20 to 30 percent of people who harbor the parasite will develop the disease.

Dorn has spent 14 years studying Chagas disease, mostly in Guatemala. She is continuing her work on the insects that carry the Chagas parasite in Central America and Mexico and working with researchers at the Louisiana State University Veterinary School on Chagas in dogs in Louisiana.

Dr. Dorn's scholarly paper on this finding will soon be published in the journal of Emerging Infectious Diseases which is published by the Centers for Disease Control. She also presented her findings at the annual meeting of American Association of Tropical Medicine and Hygiene in Atlanta in November 2006.

For a brief summary of Chagas disease and its natural transmission in the United States go to the following link on Dr. Dorn's website: http://chn.loyno.edu/biology/bios/dorn-chagasresearch.html