Chagas disease is an infectious disease caused by the parasite Trypanosoma cruzi. The parasite can be transmitted by insect vectors (by a blood-sucking stink bug called the tern), transplacental transmission, transfusion transmission, transmission by organ transplant, oral transmission, and laboratory accidents. clinical progression after T. cruzi infection includes acute and chronic phases. The acute phase is mostly asymptomatic, but in rare cases, symptoms include fever, lymphadenopathy, hepatosplenomegaly, anemia, anorexia, diarrhea, chagoma, myocarditis, or in newborns infected from mother to child, hepatosplenomegaly, hepatitis, sepsis, meningitis, myocarditis, and anemia. Usually, the infected person is undetectable during the acute phase, which lasts for weeks or months. Unless the infected person receives treatment, the disease progresses to the chronic phase. Infected individuals in the chronic phase are classified as having indeterminate disease type (no organ involvement, but infectious), cardiac disease type (one or more characteristic ECG abnormalities), and gastrointestinal disease type (upper gastrointestinal symptoms or areas of lower gastrointestinal involvement).
Chagas disease is considered endemic in 21 countries in Latin America. This is because the vector insect, the cow tortoise, is found in this region. However, with the migration of people, Chagas disease has become a global problem. Today, it is estimated that more than 6 million people worldwide are affected by Chagas disease, with an annual incidence of 39,000 cases and 12,000 deaths from the disease each year. Japan is one of the non-endemic countries for Chagas disease, but an estimated 3,000 infected people are believed to live there. The Japanese Red Cross reports a prevalence of 0.02% among blood donors at risk of infection, such as those who have lived in Latin America in the past. Another field study showed a T. cruzi infection rate of 1.6% among Latin American residents in Japan, including 5.3% among those from Bolivia.
The diagnosis of T. cruzi infection is based on parasitological, molecular, and serological tests. It is important to note that the type of test used depends on whether the disease is acute or chronic. Generally, in the acute stage, parasite levels are high in the blood, so parasitological and molecular tests are used. In the chronic stage, parasite levels are low and the diagnosis is made by serological tests.
Treatment of Chagas disease includes administration of antiparasitic medications, treatment of the chronic patient’s underlying disease, and care required by the chronic disease.There are two antiparasitic medications for the treatment of T. cruzi infection: benznidazole and nifurtimox. Benznidazole is generally considered the first-line treatment. Not all patients benefit from the administration of antiparasitic drugs. Extreme caution must be exercised in determining the indication for treatment.
Accurate and prompt diagnosis and treatment of Chagas disease requires understanding the patient’s own concepts, fears, and prejudices about Chagas disease and removing socio-cultural barriers. The involvement of social workers, mental health professionals, and peer support groups is ideal. In Japan, many patients are immigrants from overseas and tend to have difficulty accessing medical services due to differences in language, politics, and culture. Information about Chagas disease should be provided in their native language, preferably with as little medical jargon as possible.
For more information, please visit the Chagas Disease Portal for Medical Care.
2024/11/05
Responsibility: Kota Yoshioka (Nagasaki University, School of Tropical Medicine and Global Health)
