Deltaretrovirus

Deltaretrovirus is a genus of viruses in the family Retroviridae. These viruses are known to infect both humans and animals, causing a variety of diseases. The most well-known members of this genus are the Human T-lymphotropic virus (HTLV) types 1 and 2, which are associated with certain types of cancer and neurological disorders.

Structure

Deltaretroviruses are enveloped viruses with a positive-sense, single-stranded RNA genome. The genome is approximately 8.5 kb in length and contains the typical retroviral genes: gag, pol, and env, which encode for structural proteins, enzymes, and envelope proteins, respectively. The virus also contains regulatory genes such as tax and rex, which play crucial roles in viral replication and pathogenesis.

Replication Cycle

The replication cycle of deltaretroviruses follows the general pattern of retroviruses. After entry into the host cell, the viral RNA is reverse transcribed into DNA by the viral enzyme reverse transcriptase. This DNA is then integrated into the host genome by the enzyme integrase. The integrated viral DNA, known as the provirus, can then be transcribed and translated to produce new viral particles.

Pathogenesis

Deltaretroviruses are associated with a range of diseases. HTLV-1 is linked to adult T-cell leukemia/lymphoma (ATLL) and a neurological condition known as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-2 has been less clearly associated with disease but has been linked to certain neurological disorders and hematological abnormalities.

Epidemiology

HTLV-1 is endemic in certain regions, including parts of Japan, the Caribbean, South America, and Africa. The virus is primarily transmitted through blood transfusions, sexual contact, and from mother to child, either in utero, during birth, or through breastfeeding. HTLV-2 is found mainly among intravenous drug users and certain indigenous populations in the Americas.

Diagnosis and Treatment

Diagnosis of HTLV infection is typically made through serological tests that detect antibodies against the virus. Polymerase chain reaction (PCR) can also be used to detect viral DNA. There is currently no cure for HTLV infection, and treatment is primarily supportive. Antiretroviral therapy used for HIV has shown limited effectiveness against HTLV.

Prevention

Preventive measures include screening blood donations for HTLV, promoting safe sex practices, and encouraging alternatives to breastfeeding in infected mothers. Public health efforts in endemic areas focus on education and reducing transmission risks.

Related Pages

• Retrovirus
• Human T-lymphotropic virus
• Adult T-cell leukemia/lymphoma
• HTLV-1-associated myelopathy/tropical spastic paraparesis
• Reverse transcriptase
• Integrase