A Systematic Review of the Incidence, Risk Factors and Case Fatality Rates of Invasive Nontyphoidal Salmonella (iNTS) Disease in Africa (1966 to 2014)

PLoS Negl Trop Dis. 2017 Jan 5;11(1):e0005118. doi: 10.1371/journal.pntd.0005118. eCollection 2017 Jan.

Abstract

This study systematically reviews the literature on the occurrence, incidence and case fatality rate (CFR) of invasive nontyphoidal Salmonella (iNTS) disease in Africa from 1966 to 2014. Data on the burden of iNTS disease in Africa are sparse and generally have not been aggregated, making it difficult to describe the epidemiology that is needed to inform the development and implementation of effective prevention and control policies. This study involved a comprehensive search of PubMed and Embase databases. It documents the geographical spread of iNTS disease over time in Africa, and describes its reported incidence, risk factors and CFR. We found that Nontyphoidal Salmonella (NTS) have been reported as a cause of bacteraemia in 33 out of 54 African countries, spanning the five geographical regions of Africa, and especially in sub-Saharan Africa since 1966. Our review indicates that NTS have been responsible for up to 39% of community acquired blood stream infections in sub-Saharan Africa with an average CFR of 19%. Salmonella Typhimurium and Enteritidis are the major serovars implicated and together have been responsible for 91%% of the cases of iNTS disease, (where serotype was determined), reported in Africa. The study confirms that iNTS disease is more prevalent amongst Human Immunodeficiency Virus (HIV)-infected individuals, infants, and young children with malaria, anaemia and malnutrition. In conclusion, iNTS disease is a substantial cause of community-acquired bacteraemia in Africa. Given the high morbidity and mortality of iNTS disease in Africa, it is important to develop effective prevention and control strategies including vaccination.

Publication types

  • Review
  • Systematic Review

MeSH terms

  • Africa South of the Sahara / epidemiology
  • Bacteremia / epidemiology
  • Bacteremia / microbiology
  • Humans
  • Incidence
  • Risk Factors
  • Salmonella Infections / epidemiology*
  • Salmonella Infections / microbiology
  • Salmonella enterica / classification
  • Salmonella enterica / genetics
  • Salmonella enterica / isolation & purification*
  • Salmonella enterica / physiology

Grants and funding

For part of this study, IVU received a fellowship from Novartis Vaccines and Diagnostics to undertake a Master of Vaccinology and the other authors were Novartis employees. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.