Distinct epidemiological patterns of Norwalk-like virus infection

Area of Science:

• Virology
• Epidemiology
• Public Health

Background:

• Norwalk-like viruses (NLV) are a significant cause of gastroenteritis, leading to community cases and institutional outbreaks.
• Understanding the epidemiology of individual NLV antigenic types is crucial for effective control.
• Previous knowledge on the distribution of specific NLV types was limited.

Purpose of the Study:

• To investigate the epidemiology of Norwalk-like viruses (NLV) in the UK.
• To determine the predominant antigenic types of NLV causing gastroenteritis outbreaks.
• To analyze the temporal distribution of different NLV strains.

Main Methods:

• Detection of NLVs using electron microscopy in fecal specimens from 706 gastroenteritis outbreaks.
• Antigenic typing of NLV strains from 671 outbreaks using antigen capture enzyme-linked immunosorbent assays (ELISA).
• Utilized antisera against three distinct NLV types: Norwalk (NV), Mexico (MXV), and Grimsby (GRV).

Main Results:

• NLVs were identified in 68% of non-bacterial gastroenteritis outbreaks studied.
• Grimsby virus (GRV) was the predominant strain, associated with 61% of NLV outbreaks over six winter seasons (1992-1998).
• Mexico virus (MXV) showed a single epidemic peak, while Norwalk virus (NV) was linked to only two outbreaks.

Conclusions:

• A single NLV antigenic type, predominantly Grimsby virus, dominated outbreaks in the UK from 1992 to 1998.
• Findings provide insights into the epidemiological patterns of specific NLV types.
• Further research is needed for the remaining unidentified NLV strains.