Norovirus in children 5 years and below presenting with diarrhoea in KwaZulu-Natal.

Abstract

Background - NoVs are single stranded RNA viruses belonging to the family Caliciviridae. They cause gastroenteritis in all age groups but mostly in young children and the elderly. They are classified into seven genogroups (GI – GVII) and only GI, GII and GIV infect humans. They cause self-limiting infection that resolves in approximately 10 – 50 hours after exposure. Symptoms include diarrhoea, vomiting, cramps, chills and headaches. Despite a high rate of vaccine coverage in KZN through the ….., mortality among infants remains high. Therefore a study was conducted to describe the role of non-bacterial aetiologies of diarrhoea in children 5 years and under in KZN. This work investigates the contribution of NoV infection to this pathology.

Methods - Stool specimens were collected between June 2014 and August 2014 from children 5 years and below presenting with diarrhoea to a regional hospital. Written informed consent was obtained from their parents or guardian. Demographic information was collected using a structured questionnaire. The specimen were tested for NoV antigen using Enzyme Linked Immunosorbent Assay (ELISA) and Realtime Polymerase Chain Reaction (RT-qPCR) was used to detect viral RNA. The two methods were than compared with each other.

Results - One hundred and eighty-two stool specimens were collected and tested for NoV. The prevalence of NoV when specimens were tested by ELISA and RT-qPCR was 10.4 % and 22.5 % respectively. The sensitivity of the ELISA in comparison to RT-qPCR was 24.4 % (95 % Cl: 12.4 – 40.3 %) and the specificity was 93.6 % (95 % Cl: 88.2 – 97 %). The infection rate was highest in children within the age group of 12 – 24 months and all the NoV detected were of the GII genogroup

Conclusion - NoV is a common cause of diarrhoeal illness in children presenting to the King Edward VIII Hospital. Genogroup GII dominated with 100 % of all positive NoV cases belonging to this group. Taking into consideration the low sensitivity of the ELISA test, the RT-qPCR would be more suitable for routinely testing stool specimens for NoV. An effective NoV vaccine is urgently needed.