Chagas Disease (American Trypanosomiasis):
Chagas Disease is caused by Trypanosoma cruzi, a protozoan parasite found only in the Americas. It results in about 45,000 deaths annually. The disease is often acquired in childhood. In many countries in Central and South America, American Trypanosomiasis, is the most important cause of heart disease.
The parasite is transmitted by reduviid (triatomine) bugs, kissing bugs, infected by ingesting blood from animals or humans who have circulating trypanosomes (it can also be transmitted via blood transfusion or through the placenta). The protozoa are eliminated in feces of the insect and infection in humans occurs when the parasite (from the feces) penetrates the skin through the bite wound, any other wound, mucous membranes, or the conjunctiva.
As many as 70% of infected persons remain asymptomatic. The acute stage is seen principally in children and lasts 1–2 months. The earliest findings are at the site of inoculation. A common site for this to occur is the eye, and results in the Romaña sign, a swelling of the infected eye that appears as a conjunctivits. If infected through the skin a chagoma, swelling with local lymphadenopathy, may occur. Subsequent symptoms include fever, malaise, headache, enlarged spleen, and generalized lymphadenopathy. Acute myocarditis and meningoencephalitis are rare but can be fatal.
Chagas Disease can also become chronic manifesting as abnormalities in cardiac and smooth muscle. Cardiac disease includes arrhythmias, congestive heart failure, and embolic disease. Smooth muscle abnormalities lead to megaesophagus and megacolon, with trouble swallowing, regurgitation, aspiration, constipation, and abdominal pain. In immunocompromised patients, such as AIDS patients, Chagas Disease can lead to brain abscesses.
In order to diagnose Chagas Disease a blood test for the trypanosomes themselves, culture, or even inoculation of an animal may be used. The treatment of Chagas includes two drugs, nifurtimox and benznidazole. However, these often cause severe side effects and are ineffective against chronic infection. Prevention efforts include improved housing efforts (kissing bugs often live in thatched roofs) and screening before blood transfusion.
www.accessmedicine.com - Current Diagnosis and Treatment
3 years ago