Introduction

Cholera is one of the oldest and best understood epidemic diseases. Cholera is a bacterial infection which causes severe diarrhea and can eventually lead to death through severe dehydration. Typical settings for cholera are periurban slums where basic infrastructure is missing. Outbreaks of cholera can also occur on a seasonal basis in endemic areas of Asia and Africa.

Causative agent: Vibrio cholera bacteria serogroups 01 and 0139

Transmission: Infection occurs through ingestion of food or water contaminated directly or indirectly by faeces or vomitus of infected persons.

Incubation Period: Few hours to 5 days. Usually 2-3 days

Risk for travelers: Very low for most travelers, even in countries where cholera epidemics occur. Humanitarian relief workers in disaster areas and refugee camps are at risk.

Sign & Symptoms

Most infections are asymptomatic.

In mild cases, diarrhea occurs without other symptoms.

In severe cases, there is sudden onset of profuse, painless watery diarrhea/stools (rice water stools), nausea and profuse vomiting.

Complication

In untreated cases, rapid dehydration, acidosis, circulatory collapse, hypoglycemia and renal failure. Death may occur within few hours due to dehydration leading to circulatory collapse.

Treatment

Rehydration: Prompt fluid therapy with volumes of electrolyte solution

Mild or moderate fluid loss can be treated with Oral Rehydration salts,

Patient in shock should be given IV rehydration with a balanced multi-electrolyte solution.

Antibiotic: To shorten the duration of the diarrhea and reduce the volume of rehydration solutions required. The antimicrobial agents such as Tetracycline, Trimethoprim and Sulfamethoxazole (TMP-SMX), Furazolidone or Erythromycin.

Prevention & Precautions

Cholera vaccines. Vaccination is not usually advised for travelers.

• Indication
  1. Travellers in high-risk environments (low sanitary conditions) e.g. relief workers in refugee camps.
• Recommendation
  1. There are various new vaccines but they are of poor efficacy and have relatively high rate of side effects. Oral Cholera vaccines appear to provide better immunity and fewer side effects than previously available injectable vaccine. It is effective for 6 months in a single dose but is only effective against the El Tor strain.
  2. Some countries (e.g. Tanzania, Kenya, Egypt and Saudi Arabia during Hajj or Umrah) are known to require, on occasion, proof of cholera immunisation in travellers from cholera-infected countries. It is advisable to contact embassy or consulate at a destination country to confirm this requirement for cholera immunisation.

Type of vaccine: Killed and live attenuated oral

Number of doses: two (2), at least one (1) week apart (killed vaccine); one (1) dose (live vaccine)

Contraindications: Hypersensitivity to previous dose

Adverse reactions: Mild local reaction of short duration, mild systematic reaction

Before to departure: 3 weeks (killed vaccine), 1 week (live vaccine)

Consider for: Travellers with extreme risks (i.e emergency relief)

Special precautions: No antibiotics from 1 week before until 1 week after vaccination (live vaccine)

General advices to prevent infection via faeco-oral route:-

• 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.
• Drink plenty of clear, clean fluids if diarrhoea develops.
• It might be helpful to take diarrhoea medication and Oral Rehydration Salt along. If diarrhoea continues for more than 48 hours, inability to drink or is passing blood – seek immediate medical attention.

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/