Oncoviruses are a type of virus that can lead to cancer in humans and animals. They can alter the genetic material of host cells, causing them to grow uncontrollably. Some well-known oncoviruses include the human papillomavirus (HPV), which is linked to cervical cancer, and the hepatitis B virus (HBV), associated with liver cancer. These viruses can be transmitted through various means, such as sexual contact or sharing contaminated needles. Vaccines are available for some oncoviruses, like the HPV vaccine, which helps prevent certain types of cancer. Early detection and treatment are crucial for managing the risks associated with oncoviruses.