Final answer:
Hepatitis D (HDV) is the type of hepatitis that can cause a superinfection in individuals who are already infected with Hepatitis B (HBV). HDV requires HBV to replicate and can lead to more severe liver disease, which highlights the importance of HBV vaccination.
Step-by-step explanation:
The type of hepatitis that causes a superinfection, or can only infect an individual already infected with another hepatitis virus, is Hepatitis D (HDV). HDV is an enveloped ssRNA(-) virus that is circular (Baltimore Group V) and requires the presence of the Hepatitis B virus (HBV) to propagate. Therefore, it can only cause a superinfection in individuals already infected with HBV. Hepatitis B, a disease of the liver, can persist in the body, sometimes leading to chronic conditions and increasing the risk of liver cancer. HDV exacerbates these risks when it superinfects an individual with preexisting HBV.
Hepatitis D is unique among other hepatitis viruses in that it cannot replicate without the helper functions provided by HBV. This means that a person cannot be infected with HDV without first being infected with HBV. Given the severity of an HDV superinfection, which often leads to a more severe disease course, vaccination against HBV is crucial as it indirectly helps prevent HDV infection as well.
The final answer to the student's question is Hepatitis D (HDV), which is the only hepatitis virus that can cause a superinfection in an individual who is already infected with Hepatitis B (HBV). In a two line explanation: Hepatitis D (HDV) requires the presence of Hepatitis B (HBV) to propagate, thereby causing a superinfection in individuals with HBV.