Name an example of a viral infection caused by a retrovirus.

HIV (Human Immunodeficiency Virus) is a prime example of a viral infection caused by a retrovirus. Retroviruses are characterized by their ability to transcribe their RNA genome into DNA after entering a host cell. This process is facilitated by an enzyme called reverse transcriptase, which is unique to retroviruses. Once the viral RNA is converted into DNA, it can integrate into the host's genome and be replicated along with the host’s own DNA.

HIV specifically targets the immune system, particularly CD4+ T cells, leading to progressive immunodeficiency. This can make individuals more susceptible to opportunistic infections and certain cancers. Understanding the retroviral mechanism is crucial for developing effective treatments and preventive measures, such as antiretroviral therapy, which helps manage HIV infection.

The other options represent viruses with different classifications and mechanisms. Influenza is caused by an orthomyxovirus, hepatitis viruses belong to various families (like Hepadnaviridae for Hepatitis B), and herpes viruses are from the Herpesviridae family. Each of these has distinct pathogenic processes and characteristics that differentiate them from retroviruses.