# Trypanosomiasis and Chagas Disease

> Trypanosomiasis and Chagas disease for NEET-PG Medicine: sleeping sickness versus Chagas cardiomyopathy, megaorgans, vectors and drug choices compared.

- Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/trypanosomiasis-and-chagas-disease
- Exam / course: NEET-PG · Subject: Medicine
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Harrison's Principles of Internal Medicine; Ananthanarayan and Paniker's Textbook of Microbiology; Park's Textbook of Preventive and Social Medicine
- How to cite: "Trypanosomiasis and Chagas Disease", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/trypanosomiasis-and-chagas-disease

## Direct answer

Trypanosomiasis is a protozoan infection, and its two clinically important forms are African sleeping sickness, caused by Trypanosoma brucei, and American trypanosomiasis or Chagas disease, caused by Trypanosoma cruzi. Sleeping sickness is transmitted by tsetse flies and attacks the central nervous system, whereas Chagas disease is transmitted by triatomine bugs and is best known for chronic cardiomyopathy and megaorgans.

## What you must remember

- **Organisms:** Trypanosoma brucei causes African sleeping sickness, and Trypanosoma cruzi causes Chagas disease.
- **Vectors:** Tsetse flies of the genus Glossina transmit African trypanosomes, while triatomine bugs transmit T. cruzi.
- **Sleeping sickness stages:** An early haemolymphatic stage with fever and lymphadenopathy is followed by a CNS stage with sleep disturbance and meningoencephalitis.
- **Winterbottom sign:** Posterior cervical lymphadenopathy is typical of Trypanosoma brucei gambiense infection.
- **Acute Chagas signs:** Romaña's sign and a chagoma at the bite site are the classic acute features.
- **Chronic Chagas:** Cardiomyopathy with conduction defects, megaoesophagus and megacolon are the classic late manifestations.
- **Chagas drugs:** Benznidazole and nifurtimox are the drugs used, with the clearest benefit in the acute phase.
- **Indian relevance:** Neither disease is endemic in India, so both are tested as comparative textbook entities.

## Distinguishing the two diseases in a returning traveller

A 34-year-old man returns from a rural area with intermittent fever, enlarged posterior neck glands and daytime somnolence. The travel history and the organ pattern decide which trypanosome is likely.

1. **Take the travel history:** Sub-Saharan Africa suggests sleeping sickness, while Latin America suggests Chagas disease.
2. **Ask about the vector:** A tsetse fly bite points to African trypanosomiasis, whereas triatomine bugs in mud or thatched housing point to Chagas.
3. **Examine the organ pattern:** Winterbottom sign and sleep disturbance point to sleeping sickness, while cardiomyopathy, megaoesophagus and megacolon point to chronic Chagas.
4. **Examine the blood or CSF:** Thick and thin blood smears can show trypanosomes, and CSF examination with a white cell count decides whether the CNS is involved in African disease.
5. **Use serology in chronic Chagas:** Two different serological tests are used for confirmation, since a single test can mislead in chronic infection.
6. **Treat by disease and stage:** In African disease the drug depends on the haemolymphatic or CNS stage, while benznidazole or nifurtimox are the drugs of choice for Chagas.

## Where the exam tries to catch you

Most traps involve the vector, the signature signs and the choice of confirmatory test.

- **Trap:** Assuming Chagas disease is spread by the tsetse fly. — **Correct:** The triatomine bug transmits Trypanosoma cruzi, while the tsetse fly transmits African trypanosomes.
- **Trap:** Linking Romaña's sign to sleeping sickness. — **Correct:** Romaña's sign, a painless unilateral periorbital swelling, is an acute Chagas feature from conjunctival inoculation.
- **Trap:** Describing Chagas as a disease of the central nervous system. — **Correct:** Its classic late features are cardiomyopathy and megaorgans, while CNS involvement characterises African trypanosomiasis.
- **Trap:** Using a single serological test to confirm chronic Chagas. — **Correct:** Two different serological tests are used for confirmation, since a single test can give a misleading result.

## Frequently asked questions

### Which vector transmits African sleeping sickness?

The tsetse fly of the genus Glossina transmits Trypanosoma brucei, the cause of African sleeping sickness. Infection follows the bite of an infected fly in sub-Saharan Africa.

### What is Romaña's sign?

Romaña's sign is painless unilateral periorbital swelling with conjunctivitis, seen in the acute phase of Chagas disease. It results from inoculation of Trypanosoma cruzi through the conjunctiva, when infected triatomine bug faeces are rubbed into the eye.

### Which organ is the commonest serious target in chronic Chagas disease?

The heart is the commonest serious target in chronic Chagas disease, causing dilated cardiomyopathy, apical aneurysm and conduction defects. Megaoesophagus and megacolon are the other classic chronic manifestations.

### Which drugs treat Chagas disease?

Benznidazole and nifurtimox are the drugs used to treat Chagas disease, and they are most clearly beneficial in the acute phase. Their role in chronic disease is less certain and is decided by specialist guidance.

### Which drug is used for the CNS stage of Trypanosoma brucei gambiense infection?

Current WHO guidance favours oral fexinidazole for most gambiense disease, and nifurtimox-eflornithine combination therapy (NECT) for severe CNS-stage disease. Melarsoprol is an older arsenical with a risk of fatal encephalopathy, now largely replaced.