Trypanosomiasis (American) - Chagas Disease:Treatment, symptoms, advice and help
About trypanosomiasis (American)
Trypanosomiasis (American) or Chagas Disease is a tropical parasitic disease caused by the Trypanosoma cruzi, transmitted to humans from the faeces of a reduviid (triatomine) bug.
Trypanosomiasis (American): Incidence, age and sex
It occurs widely in south and Central America. Young children (1 0- 5 years) are most commonly affected.
Symptoms and signs of trypanosomiasis (American): Diagnosis
The acute phase is seen in only 1 – 2% of infected individuals. The entrance of T. cruzi through an abrasion produces a dusky-red firm swelling and enlargement of regional lymph nodes. A conjunctival lesion, although less common, is more characteristic; the unilateral firm reddish swelling of the lids may close the eye. In a few patients an acute generalized infection soon appears, with a rash, fever, lymphadenopathy and enlargement of the spleen and liver.
Investigations: T.cruzi is easily detectable in a blood firm in the acute illness. In chronic disease it may be recovered in up to 50% of cases by xenodiagnosis in which infection-free, laboratory-bred reduviid bugs are allowed to feed on the patient; subsequently, the hind gut or faeces of the bug are examined for parasites.
Causes and prevention of trypanosomiasis (American)
The cause is Trypanosoma cruzi, transmitted to humans from the faeces of a reduviid (triatomine) bug. Bugs live in the wild forests. Infected faeces are rubbed in through the conjunctiva, mucosa of mouth or nose, or abrasions of the skin. Preventive measures include improving housing and destruction of reduviid bugs by spraying of houses with insecticides. Blood donors should be screened.
Trypanosomiasis (American): Complications
Chronic phase occurs after a latent period of several years. 10 – 30% of chronic cases develop low-grade myocarditis and cardiomyopathy characterized by cardiac dilatation, arrhythmias, partial or complete heart block and sudden death. In nearly 10% of the patients, damage to Auerobach’s plexus results in dilation of various parts of the alimentary canal, especially the colon and oesophagus, so – called ‘mega’ disease. Dilatation of the bile ducts and bronchi is also a recognised sequel.
Trypanosomiasis (American): Treatment
The acute phase, congenital disease and indeterminate form of the chronic phase (within 10 years of infection) should be treated with parasiticidal drugs- Nifurtimox or Benznidazole.
This is intended to be a succinct summary of the medical issues likely to
be encountered by expeditions travelling to places remote from comprehensive
medical services Although it seems a daunting prospect to have to rely on the
knowledge and resourcefulness of expedition members, together with any medication
and equipment that they carry, the fact is that every year hundreds of such
expeditions now leave Britain and serious medical emergencies are very uncommon.
Careful planning and preparation are vital and the first requirement is that
one group member is selected to take on the role of medic early in the planning
stages. The selection may be obvious if a member has some form of medical occupation
but otherwise inclination, interest and a steady nerve are prerequisites.
Essential Background Information
Details of the itinerary should include any possible optional destinations.
Information can then be gathered on: climate including maximum ranges likely
to be encountered in terms of temperature, wind and rainfall, maximum altitude
to be reached, local diet staples as part of an overall food plan (important
statistics: one gram of carbohydrate (e.g. cooked rice and boiled potatoes yields
4.5 calories, one gram of fat 9 calories. On trek adults will need at least
4,000 calories daily – some deficit does not matter provided it continues for
no more than a few days and there is then an opportunity to “fill up”).
Diseases Likely to be Encountered
Traveller's diarrhoea is certain to be a problem in expeditions to developing
countries, especially when group members eat food they have not themselves prepared
– expect outbreaks after eating out in towns and villages.
Chest infections with purulent sputum are common in dusty, polluted environments
and at altitude. In addition to the above certainties, essential information
will include the prevalence of malaria, and the likelihood of conditions such
as Japanese encephalitis for which vaccination is required.
Fitness of members
Ideally the medic should personally and privately interview all group members
at least two months before departure and should specifically inquire about any
known health problems. It is vital that members should be encouraged to be open
by a clear statement that common conditions such as mild asthma will not lead
to a member’s being dropped but if any health problems seems significant – for
example if it has led to hospitalisation in the previous two years, then a medical
report should be asked for.
In young travellers (teens and young adults) obtain details of conditions such
as asthma, fatigue syndromes, any tendency to anxiety, depression or eating
disorders and whether female members are considering taking the contraceptive
pill to minimise problems from menstruation (there is no reason why they should
not but they should start at least a month before departure).
In older travellers the main concerns will be evidence of coronary heart disease,
chronic lung disease, overweight and details of all medication taken.
Common health problems on expedition
Problems that arise as a result of an unfamiliar environment and are likely
to be suffered to a variable extent by everybody.
Dry heat is easier to cope with because the body is able to keep its temperature
down by sweating. However this depends on increased fluid intake and without
it body temperature can rise dangerously. Frequent sips of water are the answer
with adequacy of hydration monitored by ensured by telling trekkers to ensure
that their urine has a pale colour. If it darkens they should increase their