Typhoid and Paratyphoid fever

Typhoid and paratyphoid fever are bacterial enteric fevers caused by specific serovars of Salmonella enterica, with typhoid attributed to serovar Typhi and paratyphoid to serovars Paratyphi A, B, and C ^[1][2][4]. The organism is described in the sources as a gram-negative bacillus and, more specifically, as a human-restricted pathogen in this disease context ^[1][2]. The disease corresponds to enteric fever, coded in the provided metadata as ICD-10 A01 and ICD-11 1B13.

The typical presentation is a gradual fever onset over 3–7 days accompanied by malaise, headache, and myalgia ^[1]. Clinical expression is variable and may range from fever with few other morbidities to marked toxemia and multisystem complications ^[3]. Fever is reported in the majority of patients, and symptoms may be altered by prior antimicrobial use ^[3][1]. Life-threatening complications can occur in the second week of untreated illness, and distinguishing enteric fever from other febrile illnesses is noted to be difficult ^[1].

The disease affects persons residing in, or travelling from, areas where safe water, sanitation, and hygiene infrastructure are lacking ^[1]. The sources also describe enteric fever as an important public-health problem in India ^[3]. One scholarly metadata source estimates about 27 million cases worldwide each year, almost all in the developing world, with about 200,000 deaths, though this is presented as secondary metadata rather than a primary surveillance estimate ^[4]. Source-backed detail on seasonal patterns, local incidence, or current regional distribution beyond these statements is not yet available.

Transmission is primarily by the faecal-oral route ^[1]. The sources further describe spread through contaminated food and water, including contamination associated with infected urine or faeces from acutely infected persons and chronic or convalescent carriers ^[2][4]. Direct contact with an infected person is also mentioned as a transmission pathway in the broader Salmonella literature cited here ^[2].

The sources explicitly identify persons residing in or travelling from areas lacking safe water, sanitation, and hygiene infrastructure as affected populations ^[1]. They also note higher mortality in younger children ^[3]. Beyond these statements, source-backed detail on other high-risk groups is not yet available.

Prevention in the cited sources centers on vaccination and on measures that interrupt fecal contamination of food and water ^[1][2][3]. Specifically named measures include safe water, safe food, personal hygiene, appropriate sanitation, promotion of food hygiene, and detection and control of chronic carriers ^[3][2]. The sources state that three vaccine types are available for typhoid prevention, including newer typhoid Vi-conjugate vaccines ^[1].

In surveillance practice, enteric fever should be interpreted as a febrile systemic infection that may be difficult to distinguish clinically from other causes of fever, especially when prior antimicrobial use has modified the presentation ^[1]. Blood culture is repeatedly described as the diagnostic reference or gold standard, although one source notes low sensitivity of blood culture and that bone marrow culture remains a reference standard as well ^[1][3]. Because resistant strains are noted in the sources, including ciprofloxacin-resistant and ceftriaxone-resistant typhoid in Pakistan and broader emerging antibiotic resistance, resistance context should be considered when reviewing case reports and trends ^[1][3].

1. 1 Kuehn R et al. Enteric (typhoid and paratyphoid) fever. Lancet. 2025 Sep 20. PMID: 40914181. doi: 10.1016/S0140-6736(25)01335-2. PubMed: https://pubmed.ncbi.nlm.nih.gov/40914181/
2. 2 Qamar FN et al. Salmonellosis Including Enteric Fever. Pediatr Clin North Am. 2022 Feb. PMID: 34794677. doi: 10.1016/j.pcl.2021.09.007. PubMed: https://pubmed.ncbi.nlm.nih.gov/34794677/
3. 3 Kumar P et al. Enteric Fever. Indian J Pediatr. 2017 Mar. PMID: 27796818. doi: 10.1007/s12098-016-2246-4. PubMed: https://pubmed.ncbi.nlm.nih.gov/27796818/
4. 4 Typhoid and paratyphoid fevers. Oxford Textbook of Medicine. 2010. doi: 10.1093/med/9780199204854.003.070608_update_002. DOI: https://doi.org/10.1093/med/9780199204854.003.070608_update_002
5. 5 Typhoid and Paratyphoid Fevers. Journal of the Royal Army Medical Corps. 1907. doi: 10.1136/jramc-09-02-02. DOI: https://doi.org/10.1136/jramc-09-02-02
6. 6 Typhoid and paratyphoid fever. The Lancet. 2005. doi: 10.1016/s0140-6736(05)67181-4. DOI: https://doi.org/10.1016/s0140-6736(05)67181-4

ICD-10

A01

ICD-11

1B13

Total cases

167K

Total deaths

41

Peak month

2010-08

Coverage

9 reporting countries · 2000-01-01 → 2026-06-20