Travel Medicine and Tropical Infections

INTRODUCTION

• The main diseases facing the international traveller are traveller’s diarrhoea (relatively mild) and malaria, esp. CRFM

• Infections transmitted by mosquitoes include malaria, yellow fever, Rift Valley fever, Japanese encephalitis, Zika virus and dengue fever; preventing their bites is excellent prevention

• STIs, incl. HIV, of concern in certain areas

  Prevention of disease is a key role for the GP (Table T6).

MALARIA

Prevention

Follow two simple rules:

• Avoid mosquito bites

• Take antimalarial medicines regularly

Consider:

• Smearing an insect repellent on exposed parts of the body

• Using mosquito nets

• Impregnating nets with permethrin (Ambush) or deltamethrin

Drug prophylaxis

Treatment of breakthrough malaria during travel (where medical care unavailable):

• Mefloquine 500 mg (2 tabs) statim; repeat after 6–8 h or artemether/lumefantrine (Riamet) 4 tabs at 0, 8, 24, 36, 48, 60 h

FEVER IN THE RETURNED TRAVELLER

Probability diagnosis: malaria, respiratory tract infection incl. bacterial pneumonia, gastroenteritis, dengue fever, Hepatitis A.

Serious disorders: as above, TB, typhoid, encephalitis, meningococcal meningitis, melioidosis, amoebiasis (liver abscess), all haemorrhagic fevers, schistosomiasis, African trypanosomiasis.

Investigations (if no obvious cause): FBE (?eosinophils), ESR/CRP, thick and thin blood films, blood culture, LFTs, urine M&C, stool M&C, new malaria tests, CXR.

DIARRHOEAL ILLNESSES

Traveller’s diarrhoea

The illness is usually mild and lasts only 2–3 d. Unusual to last longer than 5 d. Mainly caused by an E. coli strain.

Treatment

Mild diarrhoea

• Maintain fluid intake—cordial or diluted soft drink

• Antimotility agents (judicious use: if no blood in stools) loperamide (Imodium) 2 caps statim then 1 after each unformed stool (max. 8 caps/d)

Moderate diarrhoea

• Attend to hydration

• Patient can self-administer antibiotic—e.g. single-dose norfloxacin 800 mg (o) statim; or azithromycin (Nepal, India, Thailand)

• Imodium in ...