Purpose
- This report summarizes illnesses reported to the National Typhoid and Paratyphoid Fever Surveillance System (NTPFS) in 2017.
- Data include demographic and clinical characteristics, international travel, vaccination status, antimicrobial resistance and more.
Surveillance
JurisdictionsA reporting at least one typhoid or paratyphoid fever caseB to the NTPFS during 2017 are shown in Figures 1 and 2.
- 402 typhoid fever cases were reported by 39 jurisdictions (Figure 1).
- 63 paratyphoid fever cases were reported by 21 jurisdictions; 62 were caused by Salmonella serotype Paratyphi A, 1 by Paratyphi C (Figure 2).
Figure 1. Typhoid fever cases reported to NTPFS, by jurisdiction, 2017 (n=402)
Figure 2. Paratyphoid fever cases reported to NTPFS, by jurisdiction, 2017 (n=63)
Demographic and Clinical Characteristics of Patients
Demographic and clinical characteristics of patients with typhoid fever and paratyphoid fever are shown in Tables 1 and 2.
- The median age of patients with typhoid fever was 25 years (range 0 – 87 years).
- The median age of patients with paratyphoid fever was 27 years (range 2 – 76 years).
- There were two deaths among patients with typhoid fever. There was one death among patients with paratyphoid fever.
| Characteristic (number with data available) | Number | Percent |
|---|---|---|
| Age group, years (n = 401)
<1 |
2 |
<1 |
| 1–4 | 48 | 12 |
| 5–14 | 96 | 23 |
| 15–24 | 54 | 13 |
| 25–44 | 133 | 33 |
| 45–64 | 57 | 14 |
| 65+ | 15 | 4 |
| Female (n = 401) | 174 | 43 |
| Food handler (n = 287) | 6 | 2 |
| Outbreak-associated (n = 330) | 23 | 7 |
| International travel1 (n = 398) | 339 | 85 |
| Vaccinated2 (n = 264) | 11 | 4 |
| Specimen source (n = 396) | ||
| Blood | 327 | 83 |
| Stool | 60 | 15 |
| Other | 9 | 2 |
| Hospitalizations3 (n = 399) | 326 | 82 |
| Deaths (n = 373) | 2 | <1 |
1Travel destinations are shown in Table 3a.
2Received typhoid fever vaccination within five years before illness began. Of the 11 cases in vaccinated persons, one received only the Vi capsular polysaccharide vaccine (ViCPS); vaccine type was not reported for the other ten.
3Median length of hospitalization was five days.
| Characteristic (number with data available) | Number | Percent |
|---|---|---|
| Age group, years (n = 63)
<1 |
0 |
0 |
| 1–4 | 3 | 5 |
| 5–14 | 16 | 25 |
| 15–24 | 11 | 17 |
| 25–44 | 21 | 33 |
| 45–64 | 7 | 11 |
| 65+ | 5 | 8 |
| Female (n = 63) | 29 | 46 |
| Food handler (n = 36) | 0 | 0 |
| Outbreak-associated (n = 51) | 3 | 6 |
| International travel1 (n = 58) | 54 | 93 |
| Specimen source (n = 62) | ||
| Blood | 53 | 85 |
| Stool | 5 | 8 |
| Other | 4 | 6 |
| Hospitalizations2 (n = 63) | 50 | 79 |
| Deaths (n = 56) | 1 | 2 |
1Travel destinations are shown in Table 3b.
2Median length of hospitalization was five days.
International Travel
- Among the 398 typhoid fever patients whose travel histories were reported, 339 (85%) reported traveling or living outside the United States in the 30 days before illness began.
- Among the 58 paratyphoid fever patients whose travel histories were reported, 54 (93%) reported traveling or living outside the United States in the 30 days before illness began.
- Among patients reporting international travel, 310 (91%) patients with typhoid fever and 51 (94%) patients with paratyphoid fever reported travel to a single destination (Tables 3a and 3b).
- Visiting friends or relatives was the most common reason for international travel among patients with typhoid fever (45%) and paratyphoid fever (55%).
1Nigeria (6), El Salvador (4), Guatemala (3), Burundi (2), Dominican Republic (2), Indonesia (2), Philippines (2), Afghanistan (1), Ghana (1), Iran (1), Iraq (1), Kenya (1), Mali (1), Marshall Islands (1), Morocco (1), Nepal (1), Samoa (1), Tonga (1), Uganda (1), United Arab Emirates (1)
| Travel Destination | No. (%) |
|---|---|
| India | 29 (57) |
| Pakistan | 12 (24) |
| Bangladesh | 6 (12) |
| Indonesia | 1 (2) |
| Mali | 1 (2) |
| Other1 | 2 (4) |
1Nigeria (1), Senegal (1)
Typhoid Fever Vaccine
Figure 3. Percentage of patients with typhoid fever (n=264) who reported receiving a typhoid fever vaccine in the five years before illness began, by year, 2013–2017
This figure excludes patients whose typhoid vaccination status was unknown or not reported (n=138).
National Notifiable Diseases Surveillance System
The National Notifiable Diseases Surveillance System (NNDSS) collects and compiles reports of nationally notifiable infectious diseases, including typhoid fever.
The figure below presents a comparison of typhoid fever reports submitted to NTPFS and NNDSS in the past five years. Reports submitted to NNDSS can include clinically compatible cases that are epidemiologically linked to a confirmed case but are not laboratory-confirmed.
Comparisons for paratyphoid fever are not provided because, although it was nationally notifiable, it was reported under the case definition for salmonellosis during these years.
Figure 4. Number of typhoid fever cases reported to NNDSS and NTPFS, by year, 2013–2017
Antimicrobial Resistance
The National Antimicrobial Resistance Monitoring System (NARMS) monitors antimicrobial resistance among enteric bacteria, including Salmonella serotypes Typhi and Paratyphi A, Paratyphi B (tartrate negative), and Paratyphi C1.
Decreased susceptibility to ciprofloxacin (DSC, defined as minimum inhibitory concentration ≥0.12 µg/mL) has been associated with fluoroquinolone treatment failure among patients with Typhi infections in published literature. Multidrug-resistant (MDR) is defined as resistance to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole.
Among Salmonella serotype Typhi isolates obtained from patients during 2017:
- 73% had DSC
- 10% were MDR
- 11% were resistant to three or more classes of antibiotics
- No isolates were resistant to ceftriaxone
Among Salmonella serotype Paratyphi A isolates obtained from patients during 2017:
- 86% had DSC
- No isolates were MDR
- No isolates were resistant to three or more classes of antibiotics
- No isolates were resistant to ceftriaxone
Data are available in NARMS Now, an interactive tool containing antibiotic resistance data from bacteria isolated from humans.
Outbreaks
The Foodborne Disease Outbreak Surveillance System (FDOSS) collects reports of foodborne disease outbreaks from local, state, tribal, and territorial public health agencies.
The Waterborne Disease and Outbreak Surveillance System (WBDOSS) collects reports of waterborne disease outbreaks associated with drinking water and recreational water from local, state, tribal, and territorial public health agencies.
One outbreak of typhoid fever (none of paratyphoid fever) was reported in 2017. The outbreak occurred in Ohio and resulted in 17 laboratory-confirmed and 11 probable cases.
- Includes all 50 states and District of Columbia.
- Paratyphoid fever is caused by Salmonella serotypes Paratyphi A, Paratyphi B, and Paratyphi C. Two distinct pathotypes of Paratyphi B are recognized; one is associated with paratyphoid fever and the other is associated with uncomplicated gastroenteritis. The two pathotypes have distinct virulence characteristics and are differentiated based on the ability to ferment tartrate. The paratyphoidal pathotype is unable to ferment tartrate and is designated serotype Paratyphi B; the nonparatyphoidal pathotype ferments tartrate and is designated serotype Paratyphi B var. L(+) tartrate+. Only those isolates laboratory-confirmed as not able to ferment tartrate are included in the annual summary. Many Paratyphi B reports do not include this information; these reports are therefore excluded from this annual summary.One case of paratyphoid fever caused by Salmonella serotype Paratyphi C was reported.