Enteric fever (typhoid and paratyphoid) England, Wales and Northern Ireland: 2018
Updated 8 June 2023
Applies to England, Northern Ireland and Wales
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Enteric fever (also known as typhoid and paratyphoid) is an illness caused by the bacteria Salmonella enterica subspecies enterica serovar Typhi (typhoid) or serovars Paratyphi A, B or C (paratyphoid). Typhoid fever is a serious disease and can be life-threatening unless treated promptly with antibiotics. The disease may last several weeks and convalescence takes some time. In the literature, paratyphoid is considered to be typically milder than typhoid and of shorter duration [1] [2].
The bacteria that cause typhoid and paratyphoid only occur in humans. Humans acquire infection through eating food or drinking water that has been contaminated with infected faeces or through direct faecal-oral transmission. Transmission occurs following the ingestion of food or water that has been heavily contaminated (10 or more organisms may be required to cause illness) by the bacterium S. Typhi or S. Paratyphi. In the UK, most cases of typhoid and paratyphoid are acquired abroad in countries and regions of the world where hygiene or sanitation is poor.
This report summarises the epidemiology of laboratory-confirmed cases of S. Typhi and S. Paratyphi reported in England, Wales and Northern Ireland (EWNI) in 2018. It includes both reference laboratory and enhanced enteric fever surveillance data.
Data sources
Confirmed symptomatic cases of S. Typhi and S. Paratyphi in England, Wales and Northern Ireland are diagnosed by the UK Health Security Agency (UKHSA), then Public Health England, Salmonella Reference Service (SRS), within the Gastrointestinal Bacteria Reference Unit (GBRU) ¥. Data for laboratory-confirmed cases from 2007 onwards was extracted from the reference laboratory database using ‘date received by the laboratory’. All S. Typhi and S. Paratyphi isolates referred to the SRS undergo identification using whole genome sequencing (WGS) and single nucleotide polymorphism (SNP) typing [3] [4]. Epidemiological information was obtained from enhanced enteric fever surveillance [5]. Cases are occasionally tested multiple times for confirmation and to check the infection has cleared, therefore data has been deduplicated so that only one laboratory report for each case is counted.
Confirmed asymptomatic, probable and possible cases are analysed separately at the end of this report.
All data was analysed using Excel (Version 1808, Microsoft) and Stata (Version 15, StataCorp).
¥ As we only collect data from the UKHSA Salmonella Reference Service, local reports of cases of enteric fever may differ for Wales and Northern Ireland.
General trend
In 2018, 348 laboratory-confirmed symptomatic cases of S. Typhi and S. Paratyphi were reported by the UKHSA SRS in EWNI, an increase of 14% when compared to the 305 cases reported in 2017 (Table 1) and Figure 1). This is the largest annual increase observed since 2003. Cases of S. Typhi and S. Paratyphi decreased by an average of 7% year on year from 2011 to 2017 (range -26% to +4%) before increasing in 2018. In 2018, 58% of cases were caused by S. Typhi and 42% by S. Paratyphi A and B (Table 1). There were no cases of S. Paratyphi C reported in 2018.
Table 1. Laboratory-confirmed symptomatic cases of enteric fever, England, Wales and Northern Ireland by organism: 2009 to 2018
| Year | S.Typhi | S. Paratyphi A | S. Paratyphi B | S. Paratyphi C | Mixed infection | Total | % S. Typhi |
|---|---|---|---|---|---|---|---|
| 2009 | 247 | 185 | 25 | - | - | 457 | 54% |
| 2010 | 285 | 211 | 16 | - | - | 512 | 56% |
| 2011 | 253 | 219 | 7 | - | 1 | 480 | 53% |
| 2012 | 177 | 162 | 12 | 2 | 1 | 354 | 50% |
| 2013 | 185 | 121 | 6 | - | - | 312 | 59% |
| 2014 | 185 | 114 | 10 | 1 | 1 | 311 | 60% |
| 2015 | 169 | 107 | 26 | - | - | 302 | 56% |
| 2016 | 172 | 133 | 8 | - | - | 313 | 55% |
| 2017 | 187 | 103 | 15 | - | - | 305 | 61% |
| 2018 | 203 | 126 | 19 | - | - | 348 | 58% |
Figure 1. Laboratory-confirmed cases of S. Typhi and S. Paratyphi, with % change year to year, England, Wales and Northern Ireland: 2009 to 2018
Age and sex
In 2018, age and sex were known for all 348 confirmed symptomatic cases – 42% were adults aged between 20 and 39 years (Figure 2) and the median age was 27 years (range 0 to 91 years). Those under 15 years accounted for 28% of cases, with 1% (N=5) of the total in children under 2 years (and thus not routinely eligible for vaccination). Overall, there were slightly more female (54%) than male cases.
Figure 2. Laboratory-confirmed cases of enteric fever, England, Wales and Northern Ireland by age and sex: 2018 (N=348)
Geographical distribution
Geographical areas were assigned based on patient postcode – in a small number of cases patient postcode was missing and the sending laboratory postcode was used. The largest proportion of English cases of S. Typhi and S. Paratyphi in 2018 were reported in London (38%) which is broadly consistent with the previous year (35% in 2017) (Table 2). The largest relative increase in cases reported in 2018 compared to 2017 was seen in Yorkshire and Humber with no clear explanation for the increase. Cases in the South East, East Midlands and North East decreased compared to 2017.
Table 2. Laboratory-confirmed cases of S. Typhi and S. Paratyphi, England, Wales and Northern Ireland by geographical distribution: 2017 and 2018
| Geographical area (UKHSA centre) | 2018 | 2017 | % change |
|---|---|---|---|
| London | 127 | 102 | +25% |
| South East | 44 | 45 | -2% |
| West Midlands | 41 | 41 | +0% |
| North West | 35 | 26 | +35% |
| Yorkshire and Humber | 33 | 21 | +57% |
| East of England | 22 | 18 | +22% |
| East Midlands | 17 | 23 | -26% |
| South West | 14 | 11 | +27% |
| North East | 4 | 5 | -20% |
| England total | 337 | 292 | +15% |
| Wales | 9 | 10 | -10% |
| Northern Ireland | 2 | 3 | -33% |
| EWNI total | 348 | 305 | +14% |
Travel history
In 2018, 99% (345/348) of symptomatic laboratory-confirmed cases of S.Typhi and S. Paratyphi had travel history information (that is, whether had travelled or not) recorded (Figure 3). In 2018, 95% (332/345) of confirmed symptomatic cases with travel history information reported onset of illness within the 28-day timeframe guidelines and therefore were presumed acquired abroad, similar to 2017 (93%). Of these, 300/332 (91%) had travelled abroad from EWNI and were UK residents, while the remainder were foreign visitors to EWNI (N=18) or new entrants to EWNI (N=14). For 13 cases no foreign travel was reported (compared to 19 in 2017).
Figure 3. Laboratory-confirmed cases of enteric fever, England, Wales and Northern Ireland by travel history: 2009 to 2018
Figure 4. Reason for travel for laboratory-confirmed cases of enteric fever that travelled abroad from England, Wales and Northern Ireland: 2018 (N=300).
Where reason for travel was documented (N=285), 84% cases travelled abroad from EWNI to visit friends and relatives (VFR) (239/285), (Figure 4). The majority travelled to countries in the Indian subcontinent (Table 3), and acquired the infection while visiting friends or relatives abroad in Bangladesh, India and Pakistan. Since November 2016, Pakistan has had an ongoing outbreak of extensively drug-resistant (XDR) strain of S. Typhi, with resistance seen to most antibiotics used to treat enteric fever, including ampicillin, third generation cepaholsporins( bla CTX- M- 15 extended spectrum beta lactamase producer), fluroquinolones, chloramphenicol and co-trimoxazole [6]. This outbreak could indicate more typhoid circulating in Pakistan and may have contributed to an increasing trend of enteric fever cases seen in the overall UK data (Table 2).
There has been one imported case of XDR S. Typhi from Pakistan reported in 2017 and six further cases from 2018 [7]. There has been one imported case of ESBL S. Paratyphi A from Bangladesh reported in 2017 [8] [9].
Table 3. Countries of travel and ethnicity for laboratory-confirmed cases of enteric fever that travelled abroad from England, Wales and Northern Ireland to visit friends and relatives: 2018 (N=239*)
| Presumed country of origin | Ethnicity: Indian | Ethnicity: Pakistani | Ethnicity: Bangladeshi | Ethnicity: Asian other | Ethnicity: Black African | Ethnicity: White British | Ethnicity: Other/Mixed | Ethnicity: Not stated | Total |
|---|---|---|---|---|---|---|---|---|---|
| India | 97 | - | 2 | 1 | - | 1 | - | 6 | 107 |
| Pakistan | - | 79 | - | 1 | - | - | - | 10 | 90 |
| Bangladesh | 1 | - | 24 | - | - | - | 1 | - | 26 |
| Other Asia | - | 1 | - | 2 | - | 2 | 2 | 2 | 9 |
| Africa | - | - | - | - | 5 | - | - | 1 | 6 |
| Americas | - | - | - | - | - | 1 | - | - | 1 |
| Oceania | - | - | - | - | - | - | 1 | - | 1 |
| Total | 98 | 80 | 26 | 4 | 5 | 4 | 4 | 19 | 240 * |
*Note that some cases travelled to more than one country – all countries are included here so the totals will be higher than the actual number of cases.
Reasons for travel for UK resident cases, other than visiting friends and relatives (N=46) included holidays (36), business/work (paid and voluntary) (6), studying abroad (1) and religious holiday (3). Cases that did not travel to visit friends and relatives travelled to a number of countries including:
- India (33)
- Pakistan (9)
- Bangladesh (3)
- Other countries in Asia (24)
- The Americas (14)
- Africa (1)
For 15 cases reason for travel was not stated and one of these cases reported travel to France. Whilst France is not a typical risk country for typhoid [10], this case has been designated as a travel-associated case in the absence of an obvious source of infection in the UK.
Non travel-associated cases
In 2018, there were 13 confirmed cases of symptomatic enteric fever where the case reported that they did not travel in the 28 days prior to becoming symptomatic – 6 were caused by S. Typhi, 5 by S. Paratyphi B and 2 by S. Paratyphi A .
Of the 13 non-travel-associated cases, 3 cases were identified as part of an epidemiological and microbiological cluster. These were identified as being part of a 5-SNP cluster – 2 of these cases had contact with a chronic carrier (A chronic carrier is defined as a person who continues to excrete S. Typhi or S. Paratyphi for 12 months or more [11] and for the third case no potential source of transmission was identified. Of the remaining 10 cases, with no known epidemiological or microbiological links to other cases, 3 cases had contacts with a family member or friend who travelled to an endemic country. These contacts were symptomatic prior to the cases falling ill, indicating the potential source of transmission. No potential source was identified for the remaining 7 cases.
Confirmed asymptomatic cases
In 2018, there were 2 confirmed cases of asymptomatic enteric fever caused by S. Paratyphi A (n=1), and S. Typhi (n=1). One of these cases, who travelled to Ghana, was linked microbiologically to a confirmed symptomatic case using whole genome sequencing (5-SNP clusters). The other case had no known links to any confirmed cases, but the case reported travel to Bangladesh.
Probable and possible cases
In 2018, there were 9 probable and 5 possible cases of enteric fever as defined in the Public Health Operational Guidelines for Enteric Fever [11]. Of these, all 14 travelled abroad from the UK. Travel history information for the probable and possible cases is detailed in (Table 4).
Caution should be used when interpreting this data as it has not been confirmed by the UKHSA reference laboratory.
Table 4. Regions of and reason for travel for probable and possible cases of enteric fever that travelled abroad from England, Wales and Northern Ireland: 2018 (n=14)
| World region of travel | Visit friends and relatives | Holiday | Total |
|---|---|---|---|
| Pakistan | 3 | - | 3 |
| Ghana | 2 | - | 2 |
| India | 2 | - | 2 |
| Indonesia | - | 2 | 2 |
| Bangladesh | 1 | - | 1 |
| Mexico | - | 1 | 1 |
| Nepal | 1 | - | 1 |
| Nigeria | 1 | - | 1 |
| Philippines | 1 | - | 1 |
| Total | 11 | 3 | 14 |
Information resources
- NaTHNaC typhoid and paratyphoid fact sheet
- NaTHNaC food and water hygiene advice
- UKHSA Typhoid and paratyphoid page on GOV.UK
- Visiting friends and relatives abroad: health advice leaflet (also available in 12 languages, large print, Easy Read, British Sign Language, audio, video animation and braille)
- Gastrointestinal bacteria reference unit: reference and diagnostic services
References
1. Cook GC and Zumla A. ‘Manson’s tropical diseases’ Elsevier Health Sciences 2009.
2. Heymann DL. ‘Control of communicable diseases manual’ American Public Health Association 2008.
3. Chattaway MA, and others. ‘The Transformation of Reference Microbiology Methods and Surveillance for Salmonella With the Use of Whole Genome Sequencing in England and Wales’ Front Public Health 2019, volume 7, page 317 (viewed 20 January 2022).
4. Dallman TJ, and others. ‘A database solution for routine sequencing analysis of bacterial isolates’ bioRxiv 189118 (viewed 20 January 2022).
5. Typhoid and paratyphoid: guidance, data and analysis. Health Protection Collection’ [online] (viewed 20 January 2022).
6. World Health Organisation Disease Outbreak News Item: Typhoid fever - Islamic Republic of Pakistan (viewed 20 January 2022).
7. Godbole GS, and others. ‘First Report of CTX-M-15 Salmonella Typhi From England’. Clinical Infectious Disease 2018, volume 66, issue 12, pages 1,976 to 1,977.
8. Nair S, and others. ‘ESBL-producing strains isolated from imported cases of enteric fever in England and Wales reveal multiple chromosomal integrations of blaCTX-M-15 in XDR Salmonella Typhi’. Journal Antimicrobial Chemotherapy 2021, volume 76, issue 6, pages 1,459 to 1466.
9. Chattaway MA and others. ‘Phylogenomics and antimicrobial resistance of Salmonella Typhi and Paratyphi A, B and C in England, 2016-2019’. Microbial Genomics 2021, volume 7, issue 8, 000633.
10. National Travel Health Network and Centre. Country Information Pages (viewed 20 January 2022).
11. Health Protection Agency and the Chartered Institute of Environmental Health. Public Health Operational Guidelines for Typhoid and Paratyphoid (Enteric Fever) London, Health Protection Agency 2012 (viewed 20 January 2022).