What is it?
Chagas is a tropical disease spread by a subfamily of blood-sucking insects known as assassin bugs that like to target the lip region (hence the name). The insect, Trypanosoma cruzi, is a parasite related to the African trypanosome that causes sleeping sickness.
The underreported and undertreated condition known as Chagas disease is a health threat similar to the early years of the HIV/AIDS pandemic, according to an editorial by doctors writing for the journal PLoS Neglected Tropical Diseases. More than 8 million people have been infected by Chagas, most of them in Latin and Central America. But due to immigration, the disease also affects more than 300,000 people in the United States.
The editorial, published by the Public Library of Science's Neglected Tropical Diseases, said the spread of the disease is reminiscent of the early years of HIV.
Similar to HIV/AIDS
"There are a number of striking similarities between people living with Chagas disease and people living with HIV/AIDS," the authors wrote, "particularly for those with HIV/AIDS who contracted the disease in the first two decades of the HIV/AIDS epidemic."
Both diseases disproportionately affect people living in poverty, both are chronic conditions requiring prolonged, expensive treatment, and as with patients in the first two decades of the HIV/AIDS epidemic, "most patients with Chagas disease do not have access to health care facilities."
Unlike HIV, Chagas is not a sexually-transmitted disease: it's "caused by parasites transmitted to humans by blood-sucking insects," as the New York Times put it.How is it contracted?
"It likes to bite you on the face," CNN reported. "It's called the kissing bug. When it ingests your blood, it excretes the parasite at the same time. When you wake up and scratch the itch, the parasite moves into the wound and you're infected." The disease can also be transmitted via blood transfusion, organ transplant or from mother to child during pregnancy.
Once infected, Chagas disease (also known as American trypanosomiasis) can go undetected for years, or even decades, during which time it can cause damage to the heart, intestines and esophagus. Cardiomyopathy and arrhythmias caused by the damage can eventually prove fatal. In some cases, a Chagas-enlarged heart or intestines can actually explode.
Symptoms
Chagas disease has two phases: acute and chronic. The acute phase may have no symptoms or very mild symptoms. Symptoms include:- Fever
- General ill feeling (malaise)
- Swelling of one eye
- Swollen red area at site of insect bite
- Constipation
- Digestive problems
- Pain in the abdomen
- Swallowing difficulties
According to the PLoS editorial, about 10 million people are currently living with Chagas disease, making it one of the most common neglected tropical diseases in Latin America and the Caribbean. It kills about 20,000 people worldwide every year. Lead author Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, warns that the disease is spreading globally and there may be between 300,000 and 1 million cases in the U.S.
And while just 20 percent of those infected with Chagas develop a life-threatening form of the disease, Chagas is "hard or impossible to cure," the Times reports:
The disease can be transmitted from mother to child or by blood transfusion. About a quarter of its victims eventually will develop enlarged hearts or intestines, which can fail or burst, causing sudden death.
Treating Chagas
"The problem is once the heart symptoms start, which is the most dreaded complication—the Chagas cardiomyopathy—the medicines no longer work very well," Dr. Peter Hotez, a researcher at Baylor College of Medicine and one of the editorial's authors, told CNN. "Problem No. 2: the medicines are extremely toxic."Treatment involves harsh drugs taken for up to three months and works only if the disease is caught early. The two drugs used to treat this infection are benznidazole and nifurtimox. Both drugs often have side effects. The side effects may be worse in older people.
Side effects may include:
- Headaches and dizziness
- Loss of appetite and weight loss
- Neuropathy
- Problems sleeping
- Skin rashes
Physical examination can confirm the symptoms. Signs may include:
- Cardiomyopathy
- Enlarged liver and spleen
- Enlarged lymph nodes
- Irregular heartbeat (arrhythmia)
- Rapid heartbeat (tachycardia)
- Blood culture
- Chest x-ray
- Echocardiogram
- Electrocardiogram (ECG)
- Enzyme-linked immunoassay (ELISA)
- Peripheral blood smear
Insect control with insecticides and houses that are less likely to have high insect populations will help control the spread of the disease.
Blood banks in Central and South America screen donors for exposure to the parasite. The blood is discarded if the donor tests positive. Most blood banks in the United States began screening for Chagas disease in 2007.
The American Red Cross routinely screens blood donations for Chagas, but screening policies and requirements vary by location and organization. Texas does not require screening, nor are physicians in the state required to report instances of the disease, according to Wired.
The CDC has targeted Chagas disease and four other neglected parasitic diseases for public health action.
Sources:
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002348/
http://www.mnn.com/health/fitness-well-being/stories/chagas-disease-called-the-new-hivaids-of-the-americas
http://news.yahoo.com/blogs/lookout/chagas-tropical-disease-really-aids-145745645.html
Kirchhoff LV. Trypanosoma species (American trypanosomiasis, Chagas' disease): Biology of trypanosomes. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 277.
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