Introduction

Typhoid is a bacterial infection of the digestive tract. Worldwide, the disease occurs most commonly in association with poor standards of hygiene in food preparation and handling and where sanitary disposal of sewage is lacking

Generally low risk for travelers, except in parts of north and west Africa, in South Asia and in Peru. Elsewhere, travelers are usually at risk only when exposed to low standards of hygiene with respect to food handling, control of drinking water quality and sewage disposal.

Causative agent: Salmonella typhi, the typhoid bacillus, which infects only humans. Similar paratyphoid and enteric fevers are caused by other species of Salmonella, which infect domestic animals as well as humans.

Transmission: Transmitted by consumption of contaminated food and water. Occasionally direct faecal-oral transmission may occur.

Incubation period: From 3 days to 3 months with a usual range of 1 – 3 weeks.

Sign & Symptoms

Severe cases are characterized by gradual onset of fever, headache, malaise, anorexia and insomnia. Constipation is more common than diarrhea in adults and older children.

In white skinned patients, pink spots (papules) which fade on pressure appear on the skin of the trunk in up to 50% of cases.

In the third week untreated cases develop additional gastrointestinal and other complications which may prove fatal.

2 – 5% of those who contract typhoid fever become chronic carriers as bacteria persist in the biliary tract after symptoms have resolved.

Complication

Hepatosplenomegaly, pneumonia and chronic carriers

Treatment

Symptomatic treatment: Advise rest, drink plenty of fluids and take antipyretic (e.g. Paracetamol) to relieve symptom of fever.

Antibiotics: Chloramphenicol, Amoxycillin or Ciprofloxacin

Prevention & Precautions

1. General advices to prevent infection via faeco-oral route or contaminated food:-
   • Wash hands and soap before eating, handling food and after using toilet.
   • Boil any drinking water of unsure cleanliness or drink bottled water (checking seal is in place) or carbonated water.
   • Foods that require little handling are safer. Peel all fruit. Avoid salads or uncooked vegetables.
   • Ensure that seafood, fish and meat are thoroughly cooked and eaten hot whenever possible.
   • Eat early if one is served a buffet.
   • Avoid ready – to – eat food from roadside vendors.
2. Vaccination

Type of vaccine: Both vaccines are safe and effective.

3. 1. Oral Ty 21a: Live attenuated mutant strain of Salmonella typhi Ty21a, supplied as liquid or enteric coated capsules. Given orally in 3 doses (4 in USA) 2 days apart. Produces protection 7 days after the final dose. 67% protective efficacy- 7 years after the final dose,
   2. injectable Vi CPS: capsular Vi polysaccharide vaccine (Vi CPS), given i.m. in a single dose and produces protection 7 days after injection.

Protective efficacy is 72% after 1.5 years and 50% 3 years after vaccination.

Number of doses:

One of Vi CPS i.m.

3 or 4 of live Ty21a, given orally at 2-day intervals as liquid or enteric coated capsule.

Booster: Every 2 to 3 years for Vi CPS, for Ty21a every 7 years

Contraindications: Stop Proguanil, mefloquine and antibiotics one (1) week before starting Ty21a until one (1) week after.

Adverse reactions: None significant

Before departure: one week (1)

Recommended for: Travellers to high risk areas and travelers staying longer than one (1) month or likely to consume food or beverages away from the usual tourist routes in developing countries

Special precautions: Vi CPS is not under 2 years of age; avoid Proguanil, mefloquine and antibiotics with Ty21a.

References organisation/ support

International Travel & Health, WHO 2006

Control of Communicable Diseases Manual, 18th Edition by David L. Heymann, MD, Editor, 2004

http://travelhealth.co.uk/