Are Enteric Fever Cases Rising in South Africa?
Enteric fever, which includes typhoid fever and paratyphoid fever, is a serious illness caused by certain types of Salmonella bacteria. The main culprits are Salmonella Typhi for typhoid and Salmonella Paratyphi A, B, and occasionally C for paratyphoid.
The bacteria that cause enteric fever only target humans. They spread through contaminated food or water, often because of poor hygiene practices. For example, when someone carrying the bacteria doesn’t wash their hands properly after using the bathroom and then handles food or water. The result? A potential outbreak of illness. The bacteria thrive in close-knit environments, like households, or when water sources become compromised.
Once infected, people usually develop symptoms within 7-14 days, though it can range from as little as 3 days to as long as 60 days. The hallmark of this infection is a prolonged fever, but the symptoms are wide-ranging. People may also experience fatigue, abdominal pain, diarrhoea, or constipation.
South Africa is endemic to enteric fever caused by Salmonella Typhi, although the disease prevalence is much lower than in most other countries in sub-Saharan Africa. Sporadic cases occur in most or all provinces annually, with occasional clusters or larger outbreaks. The last large outbreak of enteric fever in South Africa occurred in Delmas, Mpumalanga Province, in 2005, with over 600 clinically diagnosed cases. Paratyphoid fever remains uncommon in South Africa. Typhoid fever has been largely eliminated in higher-income countries through the provision of modern sanitary facilities and safe drinking water.
The World Health Organization estimates that, globally, nine million cases of typhoid fever occur annually, resulting in approximately 110 000 deaths per year. South Asia, Southeast Asia, and sub-Saharan Africa bear the highest burden of enteric fever disease, with marked inter- and intra-country heterogeneity.
This report summarises the findings of the national laboratory surveillance programme that systematically gathers, compiles, and analyses data on significant public health pathogens in South Africa. This involves reporting trends in enteric fever incidence over time, detecting outbreaks, monitoring for antimicrobial resistance, and detailing the molecular epidemiology of isolates.
Materials and Methods
The Centre for Enteric Diseases (CED) of the National Institute for Communicable Diseases (NICD) provides reference microbiology testing, surveillance, epidemiological, and technical support to the South African National Department of Health’s response to enteric diseases. The NICD, a division of the National Health Laboratory Service (NHLS), participates in national laboratory-based surveillance for organisms of public health importance, including Salmonella, through the NICD GERMS-SA surveillance platform. Following identification of Salmonella Typhi at any public or private laboratory, isolates are submitted to the CED for further testing, including phenotypic characterisation, antimicrobial susceptibility testing, and whole genome sequencing (WGS).
Results
From 2005 to 2021, enteric fever cases in South Africa were consistently low, averaging 102 cases annually. Between 2020 and 2023, the majority of cases (87%) were reported by the public sector. Diagnosis was mostly through blood culture (80%) and stool culture (12%). Salmonella Typhi caused 98% of cases, while S. Paratyphi caused 2%. The most affected age group was 15-49 years (50%), followed by those under 15 years (42%) and 50-64 years (6%). Males accounted for 62% of cases. The percentage of cases with isolates received ranged from 87% to 95% across the years 2020-2023.
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