Non-UK Infections

Overview

Typhoid fever is a systemic bacterial disease caused by the Gram-negative bacterium, Salmonella typhi. The bacteria are transmitted through the ingestion of food or drink contaminated with urine or faeces of an infected individual. Water sources polluted with Salmonella typhi can produce typhoid fever epidemics where large numbers of people use the same source for drinking water. Typhoid is extremely contagious and spreads throughout the body affecting many organs. If left untreated, serious gastrointestinal and cerebral complications can develop which are fatal in 10-20% of cases.

 

The prevalence of Typhoid fever is common worldwide with the exceptions of the United States, Canada, Western Europe, Australia and Japan. Countries in the developing world such as Asia, Africa and Latin America show the highest risk. The World Health Organisation estimated approximately 21 million cases and 222,000 typhoid-related deaths occurred worldwide in 2014. Typhoid fever is uncommon in the UK with an estimated case number of 500 per year. The majority of cases were transmitted during travel to Bangladesh, India and Pakistan to visit family.

 

Signs and symptoms

Typhoid fever has an incubation period which ranges from 8-14 days. Signs and symptoms then present including:

• Fever of 39-40⁰C

• Headache

• Myalgia

• Gastrointestinal pain

• Nausea

• Anorexia

• Constipation (adults) / diarrhoea (children)

• Rash consisting of small pink spots on the trunk

• Exhaustion

• Confusion

 

Complications are experienced in 10% of cases, usually where inappropriate antibiotics are used, or where treatment wasn’t initiated soon to the onset. Complications include:

• Internal bleeding in the gastrointestinal tract

• Perforation of part of the digestive system or bowel – spreads infection to local tissue to cause peritonitis

• Sepsis

• Bradycardia

• Hepatosplenomegaly

 

Causes

The typhoid bacillus is transmitted through consumption of

contaminated food or water. Direct faecal-oral transmission is also

possible. Food products which have been in contact with the

bacterium include shellfish (from sewage-polluted areas), raw fruit and

vegetables (fertilized by human excrement) and contaminated milk

products. Flies can also cause infection in humans through the transfer

of Salmonella typhi to foods which are then consumed.

 

Once ingested S. typhi multiply in the small intestine and rapidly

penetrate the mucosal epithelium. The bacilli enter the bloodstream by

lymph drainage from mesenteric nodes and then circulate general

circulation. S.typhi undergo a silent primary bacteraemia phase to

then reach high intracellular levels throughout the spleen, liver and bone marrow where they reside during the incubation period. Upon re-entering the bloodstream, S.typhi accumulates in the bowel to cause bleeding and peritonitis.

 

Risk factors / at risk groups

• Areas with poor sanitation

• Limited access to clean drinking water

 

Diagnosis / microbiology testing

Definite diagnosis is achieved through isolation of S.typhi from cultures of blood, stool or bone marrow. Serological tests exist but are neither sensitive or specific enough for clinical use.

 

Treatment

Rehydration therapy may be required in patients showing symptoms of dehydration from prolonged diarrhoea or fever.

In severe cases, surgery may be required where perforation and internal bleeding has occurred.

 

Uncomplicated typhoid managed in the community or as an outpatient:

• Fully susceptible: fluoroquinone 15mg/kg/day for 5-7 days

• Multi-drug resistant: fluoroquinone (ciprofloxacin, ofloxacin or plefloxacin) 15mg/kg/day for 5-7 days

• Nalidixic acid resistant: azithromycin 8-10mg/kg/day for 10 days

 

Severe typhoid managed in hospital setting:

• Fully susceptible: fluoroquinone 15mg/kg/day for 10-14 days

• Multi-drug resistant: fluoroquinone (ciprofloxacin, ofloxacin or plefloxacin) 15mg/kg/day for 10-14 days

• Nalidixic acid resistant: ceftriaxone 60mg/kg/day or cefotaxime 80mg/kg/day for 10-14 days

 

Ceftriaxine is considered first line treatment in the UK for imported cases of typhoid fever. Ciprofloxacin, azithromycin, ampicillin or co-trimoxazole may be considered in cases where susceptibility results are available.

 

Vaccines / preventative measures

Two vaccinations are available for the prophylaxis of Typhoid fever, both of which are recommended to travellers. The World Health Organisation also recommends the administration of vaccines to control endemic disease and to control any outbreaks. Efficacy in the first year ranges from 50-80% decreasing to 31-76% in the second year. Booster vaccinations are recommended if the individual continues to travel to endemic areas.