It has no independent life cycle, but can survive and replicate as long as HBV infection persists in the host body. It can only cause infection when encapsulated by hepatitis B virus surface antigens. The vaccine for hepatitis B protects against hepatitis D virus because of the latters dependence on the presence of hepatitis B virus for it to replicate. Hepatitis E
Hepatitis E is caused by the Hepatitis E virus (HEV), from the family Hepeviridae. It produces symptoms similar to hepatitis A, although it can take a fulminant course in some patients, particularly pregnant women (mortality rate about 20%); chronic infections may occur in immune-compromised patients. It is more prevalent in the Indian subcontinent. The virus is feco-orally transmitted and is usually self-limited. Hepatitis F virus
Hepatitis F virus (HFV) is a hypothetical virus linked to certain cases of hepatitis. Several hepatitis F virus candidates emerged in the 1990s, but none of these reports have been substantiated. GB virus C
The GB virus C is a virus that is probably spread by blood and sexual contact. It was initially identified as Hepatitis G virus. There is very little evidence that this virus causes hepatitis, as it does not appear to replicate primarily in the liver. It is now classified as GB virus C.

2022 hepatitis of unknown origin
In 2022, several hundred cases of acute hepatitis of probable infectious origin were reported worldwide. As of May 2022, the virus causing these cases has not been identified, but an adenovirus is suspected.
Dissociative fugue (), formerly called a fugue state or psychogenic fugue, is a mental and behavioral disorder that is classified variously as a dissociative disorder, a conversion disorder, and a somatic symptom disorder. The disorder is a rare psychiatric phenomenon characterized by reversible amnesia for ones identity, including the memories, personality, and other identifying characteristics of individuality. The state can last for days, months or longer. Dissociative fugue usually involves unplanned travel or wandering and is sometimes accompanied by the establishment of a new identity. It is a facet of dissociative amnesia, according to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). After recovery from a fugue state, previous memories usually return intact, and further treatment is unnecessary. An episode of fugue is not characterized as attributable to a psychiatric disorder if it can be related to the ingestion of psychotropic substances, to physical trauma, to a general medical condition or to dissociative identity disorder, delirium, or dementia. Fugues are precipitated by a series of long-term traumatic episodes. It is most commonly associated with childhood victims of sexual abuse who learn to dissociate memory of the abuse (dissociative amnesia). Signs and symptoms
Symptoms of a dissociative fugue include mild confusion and once the fugue ends, possible depression, grief, shame, and discomfort. People have also experienced a post-fugue anger. Another symptom of the fugue state can consist of loss of ones identity.