Norovirus and Sapovirus Epidemiology and Strain Characteristics among Navajo and Apache Infants

Area of Science:

• Viral gastroenteritis epidemiology
• Pediatric infectious diseases
• Molecular epidemiology of enteric viruses

Background:

• American Indian infants historically experience a high burden of acute gastroenteritis (AGE).
• Norovirus and sapovirus are significant global causes of AGE, particularly in young children.
• Understanding viral etiology in vulnerable populations is crucial for public health interventions.

Purpose of the Study:

• To investigate the prevalence and molecular epidemiology of norovirus and sapovirus in American Indian infants.
• To compare viral detection rates between infants with AGE and healthy controls.
• To identify common norovirus and sapovirus genotypes circulating in this population.

Main Methods:

• Real-time RT-PCR was used to detect norovirus (GI, GII, GIV) and sapovirus (GI, GII, GIV, GV) in stool samples.
• Samples were collected from 241 infants with AGE (cases) and 343 infants without AGE (controls) aged ≤9 months (2002-2004).
• Positive samples were genotyped via sequencing of conventional RT-PCR products.

Main Results:

• Norovirus was detected in 31.5% of cases and 20.4% of controls (p<0.001).
• GII.3 and GII.4 Farmington Hills were the most common norovirus genotypes in both cases and controls.
• Sapovirus (GI, GII, GIV) was detected at lower rates (3.3% in cases, 2.3% in controls).
• Detected norovirus and sapovirus genotypes matched those circulating in the general US population during the study period.
• A high norovirus detection rate in healthy controls indicated significant asymptomatic transmission.

Conclusions:

• Norovirus is a prevalent cause of AGE in American Indian infants.
• Asymptomatic norovirus transmission is common in young infants within these communities.
• Molecular surveillance of enteric viruses is essential for understanding disease burden and transmission dynamics in vulnerable populations.