Chagas Disease (American Trypanosomiasis or Kissing Bug Disease)

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Chagas Disease in Dogs

Can It Spread to Humans?

There are reports that dogs, especially in the southern U.S. and in particular, Texas, may be infected with these parasites and some reports imply there is a danger for humans to become infected because the vectors now reside in the southern U.S. However, the percentage of dogs found to be infected with the parasites is relatively low (about 8.8%) and it is often associated with dogs that are feral, strays, or abandoned. In Mexico, the infection rate of dogs is higher (about 17%-21%). However, all dogs are at some risk to become infected if they are bitten by the vector.

Chagas disease (kissing bug disease) facts

  • Chagas disease is an infection caused by a protozoan parasite (Trypanosoma cruzi) that can result in acute inflammatory skin changes (chagomas) and may eventually cause infection and inflammation of many other body tissues, especially those of the heart and intestinal tract.
  • Chagas disease was first described in 1909 in Brazil.
  • Chagas disease is caused by a protozoan parasite named Trypanosoma cruzi that is transmitted to humans from the feces of triatomine bugs (kissing bugs).
  • Chagas disease is not considered contagious from person to person.
  • The parasites usually enter the mammalian (human) host through the bug bite, or breaks in the skin or conjunctiva, replicate in mammalian cells, and may eventually reach other organs through the blood.
  • Chagas disease may proceed through three phases in an individual: acute, intermediate or indeterminate, and chronic.
  • Chagas disease symptoms vary widely from no symptoms to severe in the chronic phase.
  • Acute-phase symptoms of Chagas disease may be swelling and/or redness at the skin infection site (termed chagoma), rash, swollen lymph nodes, fever, head and body aches, fatigue, nausea, vomiting and/or diarrhea, liver and/or spleen enlargement, and the Romaña sign.
  • Chronic-phase symptoms and signs of Chagas disease may be irregular heartbeats, EKG changes, palpitations, fainting (syncope), cardiomyopathy, congestive heart failure, shortness of breath (dyspnea), emphysema, stroke, sudden death, chronic abdominal pain, chronic constipation, dilated colon, and difficulty swallowing.
  • Patient history, physical exam, direct microscopic visualization of the parasites, and detection of antibodies against the parasites are methods used to diagnose Chagas disease.
  • Treatment with antiparasitic drugs benznidazole (Rochagan, Ragonil) and nifurtimox (Lampit) kill or inhibit T. cruzi parasites; drugs are available from the CDC.
  • Chronic-phase patients are usually treated using treatments directed at the specific symptoms or organ damage.
  • Physicians such as cardiologists, gastroenterologists, transplant surgeons, and infectious-disease specialists may be members of a patient's treatment team.
  • There is no vaccine against Chagas disease parasites for humans, but many experts suggest that elimination of primitive housing and increasing education about the disease may prevent most cases of Chagas disease; insecticides and insect repellants may also help prevent Chagas disease.
Medically Reviewed by a Doctor on 12/2/2015

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