Typhoid Fever Outbreak in Harare, Zimbabwe, 2017–2018

On October 16, 2017, the Harare City Health Department in Zimbabwe identified a suspected case of typhoid fever in a resident of the city’s Mbare suburb. Typhoid, caused by the bacterium Salmonella enterica serovar Typhi, can be fatal. The department’s investigation soon found a cluster of 17 suspected cases — people with fever and at least one of headache, malaise, abdominal discomfort, vomiting, diarrhea, cough or constipation. A case was confirmed when Typhi grew from blood, stool or a rectal swab.

By February 24, 2018, 3,187 suspected and 191 confirmed cases had been identified.

Typhoid cases by date of symptom onset, Harare, October 2017–February 2018. Image from CDC’s page.

Water at the root

Earlier typhoid outbreaks in Harare had been linked to shortages of municipal water, which drove people to contaminated boreholes and shallow wells. In January 2018 CDC worked with the city to standardize how water quality data from wells, boreholes and municipal taps were collected and interpreted. The city and its partners combined that with work on water, sanitation and hygiene: assessing and repairing boreholes, especially those with built-in chlorinators in affected areas; fixing burst sewers; sampling municipal and borehole water; and teaching residents about typhoid.

In the hospital

At the city’s request, a CDC team reviewed the care and outcomes of 583 patients admitted with suspected typhoid to Harare’s designated treatment center from October through December 2017:

• 79 (14%) had complications, most often acute kidney injury (26), anemia (10), peritonitis (9) and electrolyte disturbances (9); one had an intestinal perforation.
• Five died, though because their cases were not culture-confirmed they were not counted as typhoid deaths.
• Cultures were processed for 286 patients, and 74 grew Typhi.
• Fifteen of 46 bacterial isolates (33%) were resistant to ciprofloxacin. Patients with resistant infections had more complications (19% against 9%) and longer illness (a median of 9 days against 7), though the differences were not statistically significant.

CDC laboratory staff helped Zimbabwe’s laboratories design a reporting protocol so that accurate antibiotic-susceptibility results were included in every report. Given the unusual pattern of resistance, public health officials recommended third-generation cephalosporins as the first-line treatment for patients living where ciprofloxacin resistance was common.

The longer fix

Poor water quality, poor sanitation and urban crowding keep driving seasonal waterborne outbreaks in Harare. Local fixes can interrupt transmission, but lasting protection will require improving the city’s whole water treatment and delivery system.

In the meantime, informed by the outbreak data, a typhoid conjugate vaccine campaign funded by Gavi was scheduled for January–February 2019, aiming to reach 350,000 people — the first use of the vaccine, and the first outbreak-response vaccination campaign, in Africa. The goal was to halt transmission and buy time for lasting water and sanitation improvements.

Sources

Based on N’cho HS, Masunda KPE, Mukeredzi I, et al., "Notes from the Field: Typhoid Fever Outbreak — Harare, Zimbabwe, October 2017–February 2018," Morbidity and Mortality Weekly Report, Centers for Disease Control and Prevention; written with the Harare City Health Department and Zimbabwe’s Ministry of Health and Child Care, and rewritten in hubnx’s own words.