Chagas disease, also known as American trypanosomiasis, is an inflammatory, infectious and life-threatening illness caused by the protozoan parasite Trypanosoma cruzi. (T. cruzi) . Carlos Chagas discovered the disease over a century ago.
Chagas disease is found mainly in endemic areas of 21 continental Latin American countries, where it is mostly transmitted when humans come into contact with faeces and/or urine of infected blood-sucking triatomine bugs (vector-borne transmission). Chagas was considered a silent and poorly visible disease.
These bugs live in the wall or roof cracks of poorly constructed homes in rural or suburban areas, becoming active at night, biting exposed areas of skin, then defecating close to the bite. link. These bugs are also known as the kissing bugs.
In the last decades the epidemiological pattern of the disease changed from a rural to a mostly urban disease, mainly due to population mobility and emigration. Increased number of cases have been spotted in Canada and the USA, in many European and some African, Eastern Mediterranean and Western Pacific countries. Chagas is now recognised as a neglected worldwide disease with a high morbimortality rate and substantial social impact, emerging as a significant public health threat. link
People can also become infected by; link
- congenital transmission (from a pregnant woman to her baby)
- Blood transfusions
- Organ transplantation
- Consumption of uncooked food that is contaminated with faeces from infected triatomine bugs
- Accidental laboratory exposure.
Symptoms
Chagas disease presents itself in 2 phases. Either stage can be symptom free or life threatening.
Initial acute phase lasts for about 2 months after infection. During this phase, a high number of parasites circulate in the blood but in most cases, symptoms are absent or mild and unspecific. In less than 50% of people bitten by a triatomine bug, characteristic first visible signs can be a skin lesion or a purplish swelling of the lids of one eye. Romaña’s sign is the infection of the eyelid where bug faeces are accidentally rubbed into the eye, or because the bite wound was on the same side of the face as the swelling. link
Additionally, they can present fever, headache, enlarged lymph glands, pallor, muscle pain, difficulty in breathing, swelling, and abdominal or chest pain.
Chronic phase – the parasites are hidden mainly in the heart and digestive muscles. Up to 30% of patients suffer from cardiac disorders and up to 10% suffer from digestive (typically enlargement of the oesophagus or colon), neurological or mixed alterations. In later years the infection can lead to sudden death due to cardiac arrhythmias or progressive heart failure caused by the destruction of the heart muscle and its nervous system.
Treatment
Treatment focuses on killing the parasite in acute infection and managing signs and symptoms in later stages.
Chagas disease can be treated effectively with benznidazole or nifurtimox if given soon after the infection is at the onset of the acute phase. However, the benefits reduce the longer an infected person has the disease and in older patients.
These drugs should not be administered to pregnant women or people with kidney or liver failure. Nifurtimox is not recommended to people with a either a psychiatric or neurological disorder.
Prevention
- spraying of houses and surrounding areas with residual insecticides
- house improvements and house cleanliness to prevent vector infestation
- personal preventive measures such as bed nets treated with long lasting insecticide
- wearing protective clothing
- good hygiene practices in food preparation, transportation, storage and consumption
- screening of blood donors
- testing of organ, tissue or cell donors and receivers
- access to diagnosis and treatment of people with medical indication or recommendation to do anti-parasitic treatment, especially children and women of child-bearing age before pregnancy
- screening of newborns and other children of infected mothers without previous anti-parasitic treatment to do early diagnosis and provide treatment.
Vaccination
In 2005 the World Health Organization recognised Chagas disease as one neglected tropical disease. There are currently no drugs or vaccines for preventing infection.
Travellers who sleep indoors, in well-constructed facilities are at low risk to exposure. Travellers should observe food and beverage precautions and avoid consuming salads, uncooked vegetables, unpeeled fruits, and unpasteurised fruit juices for it. link
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