Lessons of the Kissing Bug's Deadly Gift

NY Times ^ | April 12, 2005 | LAWRENCE K. ALTMAN, M.D.

[neverdem]

THE DOCTOR'S WORLD

BUENOS AIRES - When there is an extraordinary new outbreak of a well-known disease, it can provide new insights into how the disease is spread.

A case in point is Chagas' disease, which exists only in the Americas, where it has infected an estimated 16 million people and causes about 50,000 deaths each year.

This parasitic infection usually is transmitted through the bite of the kissing bug (also known as the reduviid bug and the triatomine bug). The insect lives in cracks and holes in poor housing, where it bites people, often on the face, while they sleep. Occasionally, Chagas' is transmitted through blood transfusions, organ transplants and from mother to child at birth.

Recently, Brazilian health officials have reported a widespread outbreak in which Chagas' apparently was transmitted orally through contaminated sugar cane juice. Brazil has banned the sales of the juice, which was used to make a popular drink, guarapa, which is usually consumed fresh. The product is not believed to have been exported.

Although the outbreak is small (25 laboratory-confirmed cases as of April 4), three people have died of the disease, making the outbreak unusually virulent. The ages range from 3 to 73.

The outbreak has led Brazil to ask Argentina and other neighboring countries to warn the hundreds of thousands of people who flocked to the beaches in the state of Santa Catarina and elsewhere in southern Brazil since Feb. 1 in the steamy South American summer to get medical checkups if they drank sugar cane juice and became ill. (One case was reported from Italy.)

In their investigation scientists hope to determine how the contamination of the juice occurred and how much effect food-borne transmission can play in spreading Chagas'. The investigation so far has traced the source to a single site in Navegantes, Brazil, a coastal city.

The disease is named after Carlos Chagas, a Brazilian physician who first described it, in 1909. Chagas' usually spreads when someone is bitten by an insect, engorging itself with blood and passing the parasite in its feces onto the skin.

The parasite then enters the body when an affected person scratches the skin or touches an open cut or the eyes or mouth.

The initial symptoms of Chagas' are usually mild or nonexistent. It generally takes decades for the Chagas parasite to cause death by slowly damaging heart muscle, the esophagus and the colon. By that time, drugs are ineffective in reversing the damage.

But in this outbreak, the symptoms and medical problems have developed within days after ingestion of the parasite, and they have been severe in a large proportion of victims. The most common were fever, headache, muscle aches, vomiting and a rash.

Many also experience swollen lymph glands and spleen; abdominal pain; intestinal bleeding; jaundice from liver damage; and encephalitis, said Dr. Luis G. Castellanos of the Pan American Health Organization, a branch of the World Health Organization, in Brasília. Also, Dr. Castellanos said, a buildup of fluid in the lungs has resulted from an acute infection of the heart.

Brazil has advised doctors who examine patients with symptoms suggestive of Chagas' disease to test their patients' blood for evidence of infection from the parasite, Trypanosoma cruzi.

Patients may benefit from either of two drugs: Benzonidazol, made by Roche, and Nifurtimox, made by Bayer. The drugs can be effective in treating the earliest stages of Chagas' infection, said Dr. Ricardo Gurtler, an expert in the biology and epidemiology of Chagas' disease at the University of Buenos Aires.

Dr. Kennedy L. Schisler, a specialist in allergies and immunology who practices in Iguaçu Falls, Brazil, said, "News of the outbreak has shocked and flabbergasted us," in part because of the severity of the initial symptoms. In recent years, as health workers have stopped or reduced the transmission of Chagas' by the kissing bugs in Santa Catarina and in a number of other areas, doctors have deduced in a few instances that the disease was spread through contaminated food. But documentation was limited.

Doctors have reported a couple celebrating their 50th wedding anniversary died of Chagas' after acquiring the parasite at the party. In other outbreaks, entire families have become infected by eating contaminated food in their homes.

The Santa Catarina outbreak is believed to be the largest known food-borne outbreak of Chagas' and the first that has led to an international warning, said Jennifer Marcone, a spokeswoman for the Centers for Disease Control and Prevention in Atlanta. She also said that the C.D.C. was not participating in the investigation because Brazil has many experts on Chagas' disease.

Why the symptoms appear to be more severe in this outbreak than in earlier ones is under investigation. One theory is that many more parasites entered the body from the contaminated juice than would have found their way into the blood from a bug bite. Another theory is that the victims may have been infected with an unusually virulent strain of the Chagas' parasite.

Epidemiologists theorize that animals like the gamba, carrying the reduviid bugs, could have deposited the parasite in the sugar cane and left before the cane was crushed. Another theory is that the bugs were in the sugar cane when it was crushed.

The investigations are also aimed at determining how long the parasite can survive in feces outside the reduviid bug and in fluids after the bug is crushed. The information is important because it can help health workers devise strategies to prevent oral transmission.

[neverdem]

Photo Researchers Inc.
Chagas' disease is usually transmitted by the bite of a kissing bug, top. It leaves a parasite, above, on the victim's skin. The parasite then finds a way into the body, where it can live for years.

[neverdem]

FReepmail me if you want on or off my health and science ping list.

[No Longer Free State]

The insect lives in cracks and holes in poor housing, where it bites people, often on the face, while they sleep.

Bastard bug must be a conservative because it descriminates against the poor!!!

/sarcasm

[djf]

Sounds like some kind of South American Lyme disease...

[arasina]

The ones you really have to worry about are the French kissing bugs.

[panaxanax]

One more reason to close our southern borders.

[Born Conservative]

Sounds like some kind of South American Lyme disease...

Or the human version of heartworm.

[Jeff Chandler]

Pass the DDT, please.

[Cicero]

It's a very serious illness. One of my daughters spent some time traveling around the back country of Peru, and was warned to be very careful about these bugs.

[b4its2late]

Pass the DDT, please.

Bingo.

[Rabble]

"One more reason to close our southern borders"

These bugs would still get through the border! Don't give em green cards!

[Kozak]

The bug is a relative of the agent in Sleeping Sickness endemic in Africa.

[Kozak]

Go ahead and laugh.

(Reuters) - Federal health experts on Thursday said they would consider recommending that organ donors be screened for Chagas disease after confirming the first cases of the potentially fatal parasitic infection in US transplant recipients.

The Centers for Disease Control and Prevention said three women, ranging in age from 32 to 69, contracted Chagas last year after receiving kidney, liver and pancreas transplants from an unidentified Central American donor.

Two of the women subsequently died, although only one of the deaths was attributable to Chagas. The CDC said it was not sure whether the organ donor who presumably infected the three women had died of the disease. Chagas, normally spread through the feces of a certain type of insect or by infected blood, is relatively rare in the United States but common in Latin America, where it infects between 16 and 18 million people and kills 50,000 each year.

An estimated 25,000 to 100,000 Latin American immigrants in the United States are believed to carry Chagas, which is, in its early stages, often asymptomatic or characterized by fever and other mild symptoms.

"This is a disease that we should be aware of and, unfortunately, it is not a household term. It should be," said Dr. Barbara Herwaldt, an epidemiologist in the CDC's National Center for Infectious Diseases. Herwaldt noted, however, that the discovery of Chagas among US organ recipients should not prompt people to reconsider having organ transplants or be used as an argument to limit immigration from Latin America.

Approximately 22,000 Americans receive organ transplants each year. Most cases of Chagas, when caught early, can be cured with the drugs nifurtimox or benznidazole. If left untreated for too long, the disease becomes chronic in about 10 to 30 percent of infected people, who likely remain infectious their entire lives.

[panaxanax]

I meant those people infected with the disease.....but a bug-proof wall on the border would be a good idea. Like a big bug-zapper? SNAP!!!!!