Topic overview

Start with the big picture

The lesson organizes viral infections around core virology principles. It contrasts DNA and RNA replication sites, enveloped and non-enveloped virus stability and transmission, and positive- versus negative-sense RNA. It then explains retroviral replication, reassortment in segmented viruses, and antigenic drift and shift. Clinical connections include cytopathic effects used in diagnosis, virus-specific latency reservoirs, and mechanisms by which viruses can contribute to cancer. Host responses and viral evasion are covered alongside diagnostic approaches such as PCR/NAAT and serology. The topic also compares live-attenuated and inactivated or subunit vaccines, and introduces antiviral agents, post-exposure prophylaxis, congenital infections, and biosafety considerations.