Chagas Disease

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heart muscle with chagas disease

What is Chagas Disease ?

Also called American Trypanosomiasis,[4] is an inflammatory, infectious parasitic disease affecting cardiovascular, gastrointestinal, and nervous system of humans and other mammals. This disease can affect everyone but mostly diagnose among children. It is endemic in South America, Central America, and Europe. It is potentially life threatening disease if not treat can cause a burden to life. [1.2]

chagas eye-romana s sign
Picture : Patient with swelling of eyelid also known as Romana Sign Source: jyi.org

Statistics

This disease is endemic in American countries and accounts from 8-10 million people and 300,000 up to 400,000 people in non-endemic countries around the world. A predicted number of 41,200 new cases diagnosed yearly, and 14,400 infants were born having the disease from an infected mother. [2] There are 30% people that was infected were not treated and advanced to chronic phase of CHagas disease and known for about 20 years to develop signs and symptoms of cardio and gastrointestinal manifestations.[3,7]

History of Chagas Disease

A Brazilian physician named Carlos Chagas described the disease in 1909. He worked in Oswaldo Cruz Institute, he was then asked to work for an outbreak in Brazil. The disease was first discovered in a small town of Lassance, Minas Gerais state in Brazil.[4] He discovered the intestine of a bug called Triatomine bug or “kissing bugs” containing flagellate protozoa and called it Trypanosoma cruzi.

With this discovery, he believes that this was the cause of the outbreak. He took blood samples and finally proves that the parasite is the one causing the disease. Chagas, find out that parasites affect the brain and myocardium which enlighten some manifestations of patients having the disease.[2,6]

carlos-chagas:dicoverer o chagas disease Picture of  Carlos Chagas: the discoverer of Chagas disease

Image Source:jamanetwork.com

Causes of Chagas Disease

Commonly caused by a protozoan parasite called Trypanosoma cruzi and transmitted by a bite of insect vector triatomine bugs. Almost 80% accounts to the bite of these bugs.[7]

Triatomine bugs-many of them found in America, but still some species are seen in Asia, Australia and Africa. These bugs are also called assassin bug, kissing bugs, conenose bugs and comes from the family of Reduviidae. They are known for their blood sucking capabilities and targets humans and other mammals.

Other cause includes:

  • Blood transfusion contaminated by T. cruzi
  • Ingesting food contaminated by T. cruzi [4]
  • Exposure to T. cruzi parasite
  • Organ transplant
  • Born from infected mother with T. cruzi
  • Laboratory exposure[4]

triatomine bug:vector for chagas diseasePicture : Triatomine bugs :the vector for Chagas Disease

Image Source:bvgh.org

Who are at risk of Chagas Disease ?

  • Travelers
  • Campers
  • Hunters
  • Childrens and adults[8]

Chagas Disease Signs and Symptoms

Signs and symptoms of the disease may vary depending on the phase. Chagas disease was classified into Acute Phase and Chronic Phase. Manifestations may be asymptomatic or worst may be life threatening. Acute phase signs and symptoms are present in children if not cured it will advance to chronic phase which can cause relevant damage to heart and intestines.[1]

Acute Phase: last from week to months. Some people don’t show these manifestations because the disease is sometimes asymptomatic unlike in the chronic phase.[4]

  • Romaňa sign-swollen eyelids
  • Fever and chills
  • General body malaise
  • Headache
  • Flu-like symptoms
  • Nausea and vomiting
  • Pain and redness on site of insect bite
  • Dilated heart valves
  • Irregular heart rhythm

Chronic Phase: last from years or more, associated with remission and exacerbation of signs and symptoms. Mostly the complication is in the heart and account for 20-30% people having the disease. Next is gastrointestinal and rare case is on the nervous system. This time anti parasitic medications are not effective and cannot reverse the problem. Cardiac specialist is needed to address this problem.[4]

Cardiac complications

    • Cardiomyopathy(80%)
    • Cardiomegaly
    • Cardiac Arrythmias
    • Congestive Heart Failure
    • Apical Aneurysm[1]

heart muscle with chagas diseasePicture showing damage to heart muscles

Photo Source: en.wikipidea.org

Gastrointestinal complications

  • Hepatomegaly
  • Spleenomegaly
  • Constipation
  • Megaesophagus(25%)
  • Megacolon(30%)

x ray megacolon with chagas diseaseX ray image of megacolon of the patient with Chagas Disease

Source: richardearlam.com

 Nervous system complications

    • Meningocephalitis
    • Encephalitis
    • Nerve Degeneration[2]

Chagas Disease Diagnosis

A diagnostic tool used to diagnose the disease is a blood culture wherein the parasite Trypanosoma cruzi can be microscopically seen using thin and thick blood smears stained with Giemsa.[2] A physical exam is done by a doctor to ask for signs and symptoms of disease and then ask for any exposure to kissing bugs or any risk factors associated with the disease. Some tests are beneficial to know either the disease is in acute or chronic phase so that proper treatment will be given.[1]

Additional Tests:

    • Blood smear
    • Chest X-ray
    • Abdominal X-ray
    • Echocardiogram
    • ECG (Electrocardiography)
    • ELISA (Enzyme Link Immunosorbent Assay)
    • Upper Endoscopy[3]

Chagas Disease Transmission and Life cycle

Triatomine bugs bite and suck blood of humans then defecate near the site of bite where the parasite T. cruzi is passed in blood stream. Trypomastigotes enter cells in mucous membrane of the body such as in the conjunctiva, by binary fusion trypomastigotes will be differentiated to amastigotes, this time it will burst out into cell and then pass to the blood stream of the human body. This phase will continue to invade other cells of the body. [2,9][9]

Picture : life cycle of chagas disease

Image Source: cdc.gov

Chagas Disease Treatment

Addressing the treatment of disease will be symptomatic. A specialist will be consulted to deal with signs of symptoms in cardiovascular and gastrointestinal symptoms. Top most priority is to destroy the cause of the disease which is T. cruzi, antiparasitic medication will be given to patients per doctors order.[7]

Two effective drugs to treat the disease [1,2,5]

Benznidazole- the drug of choice for Chagas Disease, oftenly given in acute phase with 80% success rate

Nifurtimox- another drug known for its therapeutic effect to treat Chagas Disease

Chagas Disease Prevention

  • Using of insecticides and pesticides[1,3]
  • Avoid exposure to triatomine bugs
  • Avert vector invasion
  • Using of mosquito nets or bed nets[1]
  • Personal Hygiene
  • Avoid going to place where triatomine bugs lives
  • Improvement of housing
  • Blood screening for blood transfusions
  • Make sure the organs for transplantation is not infected with the parasite
  • Newborn screening
  • Information Dissemination[1,3,6]

There are still no vaccines that are created nor did prophylaxis treatment for Chagas disease, following this simple prevention can help you get rid the disease.[4] Since the manifestations of having disease is sometimes asymptomatic, the best measure to do is to have a blood screening especially for those endemic areas and countries. If the signs and symptoms are getting worst better seek medical attention for proper management of Chagas disease.[6]

References:

  1. http://www.mayoclinic.com/health/chagas-disease/DS00956/DSECTION
  2. https://en.wikipedia.org/wiki/Chagas_disease
  3. http://health.nytimes.com/health/guides/disease/chagas-disease/overview.html#Exams-and-Tests
  4. http://www.cdc.gov/parasites/chagas/gen_info/detailed.html
  5. http://www.nature.com/nature/outlook/chagas/
  6. http://www.uta.edu/chagas/
  7. http://www.nlm.nih.gov/medlineplus/ency/article/001372.htm
  8. http://www.who.int/ith/diseases/trypanosomiasis/en/
  9. http://www.chagasfound.org/chagas-disease-info.php?ID=1&t=Life%20Cycle

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