Infectious Hepatitis A (HAV) is caused by which type of microorganism?

Hepatitis A is caused by a virus, specifically the Hepatitis A virus (HAV). Viruses are distinct from bacteria, protozoa, and rickettsia in several key ways. Unlike bacteria, which are single-celled organisms that can survive and reproduce on their own, viruses lack the ability to replicate independently; they require a host cell to reproduce. The presence of HAV in the body leads to inflammation of the liver, which is where the term "hepatitis" originates.

Understanding the characteristics of HAV is crucial for implementing prevention strategies, such as vaccinations and public health messaging about sanitation and hygiene practices to control its spread. The recognition of HAV as a viral pathogen is a foundational aspect of epidemiology and public health that environmental health specialists must grasp in order to manage outbreaks effectively and educate the public about the risks of infection.