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Chagas disease was first described in 1909 in Brazil by physician Carlos Chagas. It is an infectious disease caused by the parasite Trypanosoma cruzi, which is found in the faeces of the triatomine (reduviid) bug

Bug’s kiss Brazil hut
Puffed wink, stuck food, fluid glut
Right bundle branch block
Chagas Disease
Triatomite ‘Kissing’ Bug
@DrCindyCooper

About

• Is endemic in South America. Kills at least 50,000 per annum.
• It is caused by infection with the protozoan Trypanosoma cruzi

Aetiology

• The vector for this infection is the reduvid bug
• The vector gets infected by biting an infected animal or person.
• Once infected, the bugs pass T. cruzi parasites in their faeces
• Lives in the walls of houses in poor areas
• Spread through bites and across mucous membranes
• Can be spread by blood transfusion and vertically

Clinical

• Acute phase: Aches, pains, fever, headache, rash, diarrhoea, vomiting, mild hepatosplenomegaly and lymphadenopathy, oedema, myalgia, painful nodules, meningoencephalitis, myocarditis. A local swelling (a chagoma) where the parasite entered the body. Romana's sign is swelling of the eyelids on the side of the face near the bite wound or where the bug faeces were deposited or accidentally rubbed into the eye.
• Chronic phase: infection may remain silent for decades however some people develop cardiac complications such as dilated cardiomyopathy, heart failure, arrhythmias, cardio embolism, cardiac arrest. may also develop an enlarged oesophagus (mega- oesophagus) or colon (megacolon) and can lead to difficulties with eating or with passing stool.

Investigations

• FBC, U&E, ESR, CXR. ECG.
• Echocardiography to demonstrated cardiomyopathy
• Barium meal/Endoscopy shows Achalasia
• Blood smear: can observe parasite on a thick and thin blood smear. Only useful in acute infection when parasites are circulating in blood.
• Serological testing can be useful for chronic disease with detectable IgG antibodies but is not useful for acute illness

Management

• Benznidazole or nifurtimox may be used on a named patient basis. Seek expert help. Treatment is generally considered to be more effective for those in the acute or early chronic phase or during reactivation if the patient becomes immunosuppressed. It is also used in cases of congenital infection. The treatment schedule is long and is associated with frequent side effects.
• Once the characteristic pathology is established (e.g. dilated cardiomyopathy, mega- oesophagus), be aware that: antiparasitic treatment will not reverse it and symptomatic treatment is the mainstay of management
• Cardiomyopathy: rhythm control, anticoagulation.
• Megacolon: a diet high in fibre and fluids and enemas
• Mega oesophagus: dietary advice and possible balloon dilation
• Treat with triazoles which need 30-60 days of treatment and cause neurotoxicity
• Being a disease affecting only the poor has perhaps stifled success at treatment

Prevention

• Those who sleep indoors, in well-constructed facilities (for example, air-conditioned or screened hotel rooms), are at low risk for exposure to infected triatomine bugs, which infest poor-quality dwellings and are most active at night.
• Preventive measures include spraying infested dwellings, using bed nets treated with long-lasting insecticides, protective clothing, and use insect repellent to exposed skin.
• Travellers should be aware of other possible routes of transmission, including bloodborne and foodborne.
• Control strategies should focus on preventing transmission from a blood transfusion, organ transplantation, and mother-to-baby (congenital transmission).

Screen blood donors: Must not give blood if they

• Were born in South America or Central America (including southern Mexico, but not the Caribbean Islands)
• Mother was born in South America or Central America (including southern Mexico, but not the Caribbean Islands)
• Previous blood transfusion in South America or Central America (including southern Mexico, but not the Caribbean Islands)
• They lived and/or worked in rural subsistence farming communities in these countries for a continuous period of 4 weeks or more

Can donate blood if

• At least 6 months have elapsed since the last exposure and
• A validated test for T.cruzi antibody is negative

Pregnancy

• Offer serological testing for Chagas disease to at risk pregnant women, and refer any positives to a specialist centre.
• Follow up infants of seropositive mothers to detect and treat any cases of vertical transmission

Revisions

• Last updated 16/09/2017