Aetiology and pathogen-specific risk factors for diarrhoea among children under the age of 5 years

Abstract

Background Children under five years of age are most affected by diarrhoea, and co-infections may lead to more severe disease. Rotavirus vaccine introduction has altered the aetiology of diarrhoea in some high-income countries but limited data are available for low-middle income countries. The aim of this study was to investigate the aetiology of acute diarrhoea and possible risk factors associated with rotavirus diarrhoea post-rotavirus vaccine introduction in hospitalised children.Methods A secondary analysis was conducted, using data from a diarrhoeal sentinel surveillance program, which enrolled children hospitalised for acute diarrhoea at nine hospitals in South Africa (SA). A TaqMan array card was used to detect multiple enteric pathogens from stools collected during 2015-2016. The prevalence of enteropathogens was described using a polymerase chain reaction cycle threshold (Ct) of ≤35 and specific Ct cut-offs for selected pathogens. Logistic regression was performed to investigate risk factors associated with rotavirus detection in the stool of children who received at least one dose of rotavirus vaccine. Results-The analysis consisted of 793 children <5 years. Using Ct cut-off of ≤35, prominent diarrhoeal pathogens were: Enteroaggregative Escherichia coli (EAEC, 33,2%), adenovirus (28,6%), Shigella/Enteroinvasive E. Coli (EIEC, 24,1%), Cryptosporidium (23,6%), and rotavirus (22,1%). Using specific Ct cut-offs, rotavirus (20,7%), Shigella/EIEC (15,4%), and Cryptosporidium (13,0%) had the highest detection frequencies. The highest detection of rotavirus was among children 6-11 months old (35,3%), while Shigella/EIEC was highest amongst older children (24-59 months old) (50,5%) (Ct ≤35). The most prominent co-detections with rotavirus identified were Helicobacter pylori (4,9%) and Shigella/EIEC (3,7%). Children 6-11 months old (OR=4.27; 95%CI:2.022 – 9.020), admitted in winter (OR=29.57; 95%CI:13.212 – 66.164) or spring, (OR=7.05; CI:3.214 – 15.483), and hospitalised at the Red Cross Children’s Hospital (OR=2.92; 95%CI:1.139 – 7.511) had higher odds of rotavirus detection in stool despite being vaccinated against rotavirus. Participants from Klerksdorp Hospital had lower odds of rotavirus hospitalisation (OR=0.15; 95%CI:0.400 – 0.611).Conclusion Rotavirus was still a prominent cause of diarrhoea in hospitalised children <5 years old in 2015 and 2016. The prevalence of Shigella/EIEC was higher in children 24-59 months old while rotavirus was most frequently detected in younger children (6–11 months old). Development of the new rotavirus vaccines and vaccination schedules and the development of vaccines against bacteria such as Shigella would help decrease the prevalence of diarrhoeal disease in children <5 years of age.