Epidemiology

Enteric fevers are endemic in the Indian subcontinent, South East Asia, Far East Asia, the middle east, Africa, Central America and South America. S. paratyphoid type B infections also occur commonly in south and eastern parts of Europe.

In the remainder of Europe however, and in other westernised countries sporadic cases or small outbreaks occur almost exclusively as imported infections.

Estimates of the global annual incidence of typhoid fever range between 11 and 21 million cases with approximately 128,000 to 161,000 deaths per year

Typhoid is rare in resource-rich countries where standards of sanitation are high

• cases of typhoid and paratyphoid disease reported in England, Wales and Northern Ireland are usually imported due to foreign travel or contact with somebody who has travelled
  • most frequently reported region of foreign travel for typhoid and paratyphoid was the Indian subcontinent (PHE, 2018)
  • in 2016 and 2017, 93% of confirmed symptomatic cases with travel history recorded were presumed to be acquired abroad
  • between 2008 and 2017, there were an average of 387 laboratory reports of typhoid and paratyphoid each year. Approximately 40-50% of the cases were paratyphoid, of these, most were Paratyphi A

In most affected countries

• children are disproportionately affected by typhoid fever, with peak incidence occurring in individuals aged 5 to less than 15 years of age

Also patients with HIV (and other immunocompromised patients) are particularly vulnerable to Enteric fever.

Summary:

• majority of cases (95%) reported in the UK are related to travel to endemic areas
• in developed countries where standards of sanitation are high, the diseases are sporadic and are mainly associated with foreign travel
• in the UK, approximately 55% of enteric fever cases are due to S. Typhi and 45% to S. Paratyphi (majority paratyphoid A)

Risk of contracting typhoid fever is highest for travellers to areas of high endemicity. In the Indian subcontinent, a region of high incidence of typhoid fever (more than 100 cases per 100,000 people per year, the attack rate for travellers has been estimated at 1 to 10 per 100,000 journeys.

Reference:

1. GP magazine (September 24th 2004): 44.
2. PHE (2019). Recommendations for the Public Health Management of Gastrointestinal Infections.