Abstract:
Noroviruses are a major cause of viral gastroenteritis. The burden of the norovirus in
low-resource settings is not well-established due to limited data. This study reviews the norovirus
prevalence, epidemiology, and genotype diversity in lower-middle-income countries (LMIC) and
in low-income countries (LIC). PubMed was searched up to 14 January 2019 for norovirus studies
from all LIC and LMIC (World Bank Classification). Studies that tested gastroenteritis cases and/or
asymptomatic controls for norovirus by reverse transcription-polymerase chain reaction (RT-PCR)
were included. Sixty-four studies, the majority on children <5 years of age, were identified, and
14% (95% confidence interval; CI 14–15, 5158/36,288) of the gastroenteritis patients and 8% (95% CI
7–9, 423/5310) of healthy controls tested positive for norovirus. In LMIC, norovirus was detected
in 15% (95% CI 15–16) of cases and 8% (95% CI 8–10) of healthy controls. In LIC, 11% (95% CI
10–12) of symptomatic cases and 9% (95% CI 8–10) of asymptomatic controls were norovirus positive.
Norovirus genogroup II predominated overall. GII.4 was the predominant genotype in all settings,
followed by GII.3 and GII.6. The most prevalent GI strain was GI.3. Norovirus causes a significant
amount of gastroenteritis in low-resource countries, albeit with high levels of asymptomatic infection
in LIC and a high prevalence of coinfections.
