Norwalk agent-like particles associated with gastroenteritis in human beings

Area of Science:

• * Virology and Gastroenterology
• * Pathogen Discovery and Characterization

Background:

• * Six viral agents, including the Norwalk agent, are known to cause gastroenteritis.
• * These agents share similar physical properties: 25-27 nm diameter, nonenveloped structure, and high buoyant density.
• * Multiple antigenic types exist, complicating diagnosis and control.

Purpose of the Study:

• * To summarize the characteristics of known Norwalk-like viral agents.
• * To describe their detection, clinical effects, and limitations in research.
• * To anticipate the emergence of new similar agents.

Main Methods:

• * Detection of viral particles in patient stool samples using immune electron microscopy.
• * Characterization of physical properties (size, density) of the agents.
• * Review of volunteer studies on infection effects.

Main Results:

• * Viral particles identified in feces of infected individuals.
• * Infection in volunteers led to reversible jejunal mucosal changes and transient malabsorption.
• * No successful in vitro cultivation or validated animal models currently exist.

Conclusions:

• * Norwalk-like agents are significant causes of viral gastroenteritis with distinct physical properties.
• * Human volunteer studies reveal acute infection impacts intestinal mucosa and nutrient absorption.
• * Further research is needed to understand pathogenesis and develop effective models, with more agents anticipated.