Date: Thu 17 Jan 2019
Source: MMWR 2019;68(2):44-45 [edited]
Citation: N'cho HS, Masunda KP, Mukeredzi I, et al. Notes from the field: typhoid fever outbreak -- Harare, Zimbabwe, October 2017-February 2018. MMWR Morb Mortal Wkly Rep 2019;68:44-45. DOI: <http://dx.doi.org/10.15585/mmwr.mm6802a5
On 16 Oct 2017, the Harare City Health Department (HCHD) in Zimbabwe identified a suspected typhoid fever (typhoid) case in a resident of Harare's Mbare suburb. Typhoid is a potentially fatal illness caused by _Salmonella enterica_ serovar Typhi (Typhi). HCHD initiated an investigation and identified a cluster of 17 suspected typhoid cases, defined as the occurrence of fever and at least one of the following symptoms: headache, malaise, abdominal discomfort, vomiting, diarrhoea, cough, or constipation. A confirmed case had Typhi isolated from blood, stool, or rectal swab culture .
As of 24 Feb 2018 (the most recent publicly available data), 3187 suspected and 191 confirmed cases were identified [see figure in source URL above. - Mod.LL], with no reported deaths among confirmed cases. Among suspected cases, 1696 (53%) patients were male, and the median age was 17 years (range, 1 month to 90 years). In addition to clusters in Mbare, clusters were detected in Harare's western suburbs, including Kuwadzana, where high rates of ciprofloxacin-resistant Typhi were identified.
Previous typhoid outbreaks in Harare have been associated with municipal water shortages and increased use of contaminated boreholes and shallow wells [2-5]. In January 2018, the CDC collaborated with HCHD to standardize the collection, analysis, and interpretation of water quality data from wells, boreholes, and municipal taps. HCHD and partners paired this approach with efforts to improve water, sanitation, and hygiene (WASH) through assessing and repairing boreholes (particularly those with in-line chlorinators in affected areas); attending to burst sewers; conducting water sampling of municipal and borehole water; and educating local residents about typhoid. At the request of HCHD, a CDC team also conducted a review of case management and clinical outcomes among suspected typhoid patients admitted to Harare's designated typhoid treatment center from 1 Oct 2017 through 31 Dec 2017. Among 583 patients admitted with a diagnosis of suspected typhoid, complications occurred in 79 (14%), the most common being acute kidney injury (26), anemia (10), peritonitis (9), and electrolyte abnormalities (9). One patient experienced intestinal perforation, and 5 patients with suspected typhoid died; however, because these cases were not culture-confirmed, they were not reported as typhoid-related deaths. Cultures were processed for 286 (49%) inpatients; 74 (26%) yielded Typhi. In addition, 15 (33%) of 46 isolates from hospitalized patients were ciprofloxacin-resistant. Complication rates were higher (19%) and median illness duration was longer (9 days) among patients with ciprofloxacin-resistant isolates than among those with nonresistant isolates (9%; 7 days), but the differences were not statistically significant.
CDC laboratorians collaborated with Zimbabwe laboratory staff members to design a reporting protocol for laboratory results and ensure that accurate results of antimicrobial susceptibility testing were included in all reports. The standardized collection and analysis of clinical and laboratory information during an outbreak in which an unusual regional antibiotic resistance pattern featured prominently prompted public health officials to recommend 3rd-generation cephalosporins as 1st-line treatment for patients residing in areas with high rates of ciprofloxacin resistance .
The combination of poor water quality and sanitation and urban overcrowding continues to be a persistent driver of seasonal outbreaks of waterborne diseases in Harare. Although localized WASH interventions, such as those described here, serve to disrupt local transmission, comprehensive measures will be needed to improve the water treatment and delivery system in Harare. One such measure that was informed by the epidemiologic data is a Gavi-funded vaccination campaign using typhoid conjugate vaccine scheduled for January-February 2019, targeting 350 000 persons; this is the 1st use of typhoid conjugate vaccine and the 1st outbreak response vaccination campaign in Africa. The goal of this effort will be to disrupt transmission, thereby providing time for implementation of sustainable and widespread WASH interventions.
2. Davis WW, Chonzi P, Masunda KPE, et al. Notes from the field: typhoid fever outbreak -- Harare, Zimbabwe, October 2016-March 2017. MMWR Morb Mortal Wkly Rep 2018;67:342-343.
3. CDC. Notes from the field: _Salmonella_ Typhi infections associated with contaminated water -- Zimbabwe, October 2011-May 2012. MMWR Morb Mortal Wkly Rep 2012;61:435.
4. Polonsky JA, Martinez-Pino I, Nackers F, et al. Descriptive epidemiology of typhoid fever during an epidemic in Harare, Zimbabwe, 2012. PLoS One 2014;9.
5. Muti M, Gombe N, Tshimanga M, et al. Typhoid outbreak investigation in Dzivaresekwa, suburb of Harare City, Zimbabwe, 2011. Pan Afr Med J 2014;18:309.
[Vaccine intervention is an important step, as increasing antimicrobial resistance in the typhoid bacillus has made treatment more difficult.
Typhoid fever, so-called enteric fever caused by _Salmonella enterica_ serotype Typhi, has a totally different presentation from that of the more common kinds of salmonellosis. Epidemiologically, usually spread by contaminated food or water, typhoid is not a zoonosis like the more commonly seen types of salmonellosis. Clinically, vomiting and diarrhea are typically absent; indeed, constipation is frequently reported. As it is a systemic illness, blood cultures are at least as likely to be positive as stool in enteric fever, particularly early in the course of the infection, and bone marrow cultures may be the most sensitive.
The symptoms of classical typhoid fever typically include fever, anorexia, lethargy, malaise, dull continuous headache, non-productive cough, vague abdominal pain, and constipation. Despite the (often high) fever, the pulse is often only slightly elevated. During the 2nd week of the illness, there is protracted fever and mental dullness, classically called coma vigil. Diarrhea may develop but usually does not. Many patients develop hepatosplenomegaly (both liver and spleen enlarged). After the 1st week or so, many cases develop a maculopapular rash on the upper abdomen. These lesions ("rose spots") are about 2 cm (0.78 inch) in diameter and blanch on pressure. They persist for 2 to 4 days and may come and go. Mild and atypical infections are common.
The word typhoid (as in typhus-like) reflects the similarity of the louse-borne rickettsial disease epidemic typhus and that of typhoid fever; in fact, in some areas, typhoid fever is still referred to as abdominal typhus. - ProMED Mod.LL]