2007年VOA标准英语-US Doctors Find More Cases of Parasite Infectio

Doctors in the United States are seeing more infections from parasites 2 normally found in developing countries.  These infections could be prevented, contained or cured, but the problem is, many American doctors are not trained to look for signs of parasite 1 infections until sometimes it is too late. VOA's Carol Pearson reports.

The bug that transmits the T. cruzi parasites to humans, which cause Chagas disease



Chagas disease is one example of the parasitic 4 infections doctors in the U.S. are now seeing. It is caused by a microscopic 5 parasite, called T. cruzi. Dr. James Maguire, Director, International health division, University of Maryland shows the bug that causes Chagas disease.

Dr. Maguire specializes in diseases caused by parasites. Chagas disease can cause severe chronic 6 illness or death.

Los Angeles Public Health Director Jonathan Fielding says donated blood tainted 7 by T. cruzi is starting to show up in hospital operating rooms. "There have been two cases locally where somebody has gotten an organ transplant and found out that organ was infected with Chagas disease and they've developed Chagas disease."

Once in the body, the parasites literally 8 feed off organ cells such as those in the heart.  As they multiply, the cells burst.  If the parasites are in the heart, the infected person can experience sudden heart failure.  Dr. Maguire says what the blood banks in Los Angeles are finding is only part of the picture. "That's probably the tip of the iceberg 9.  There may be as much as ten times as many people who are infected, and we don't know about that. "

Most people in the U.S. with Chagas disease are immigrants from Mexico, Central and South America. Dr. Maguire says Chagas disease is difficult to cure and easy to miss during a physical examination. "Most people wouldn't know unless they had a blood test." Reporter: "And the doctor would have to be looking for it." Dr. Maguire nods and adds, "...would have to be looking for it and would have to be knowledgeable 10 about the disease."

Dr. Maguire says about half of the blood banks in the United States screen donors 11 for this parasite.

Another parasitic disease American doctors are now seeing is leishmaniasis, a painful skin condition that Dr. Nancy Crum sees on Marines returning from Iraq. "The only way you can get this parasite is through a bite of an infected sand fly."

"Usually the lesion begins two to eight weeks after the sand fly bites, and it's at the exact same location of the sand fly bite.  And it usually starts as a little tiny papule at the site, but it can expand over several days to several weeks into an ulcer 12."

The leishmania parasite invades a person's white blood cells, the cells that normally fight infection. Leishmaniasis is found in tropical or subtropical regions. The World Health Organization reports some 300 million people are at risk of getting infected.

The sores sometimes go away on their own, but it can also result in scars and disfigurement.  If the parasite invades an organ, it can kill. 

Leishmaniasis is also called kala-azar, a Hindi word for "black-sickness" because it makes the skin darker. The disease is prevalent in Sudan.  Dr. Erwin de Vries says if the disease goes untreated to can resemble other diseases. "The tragic 13 thing about kala-azar is you catch it like malaria 14 from a sand fly and it wastes you as if you have HIV/AIDS.  Within a few months time, you will look like a skeleton and you will be dead.

As terrifying as these diseases are, most of them can be prevented.  Dr. Maguire says Chagas has been wiped out in the southern cone 15 of South America. This has saved several million people from getting the disease.

Parasitologists, like Dr. Maguire, hope increasing awareness 16 in the developed world might lead to increased funding to get rid of these parasitic diseases in developing countries.  But he acknowledges there is still a long way to go.