Control and Treatment

CONTROL/PREVENTION: -

The most common method of transmission for the Hantaan virus is through infected mice, so the best way to prevent an infection is to avoid mice. However there is an effective inactivated cell culture vaccine available. This vaccine has been tested in labs and was sufficiently effective in preventing an infection. This vaccine has been available to people in Korea for the last ten years.

TREATMENT: -

For someone who is infected with the Hantaan virus the most effective treatment is intravenous Ribavirin. This drug is structurally similar to Purine RNA Nucleotides. In the presence of Ribavirin, viral RNA metabolism is disrupted and replication is inhibited. Reversible hemolytic anemia was the most commonly observed side effect but was observed in less than 25 % of patients in a study.

Disease/Pathogenesis

The first human disease known to be due to a Hantavirus infection was hemorrhagic fever with renal syndrome, identified in the early 1950s during the Korean War. Many United Nations troops developed a weird disease marked by fever, headache, hemorrhage, and acute kidney failure. Despite much research, the cause remained unknown for 26 years until a new virus; named “Hantaan virus” was isolated in Korea from field mice in 1976.

Hemorrhagic fever with renal syndrome is prevalent in China and Korea. During the seasonal disease peak times, the host rodent populations max out and the fields become full of dust (containing dry virus-laden excrement). The disease is lethal in approximately 5 to 10 percent of cases.

Hantaan virus, the etiological agent of Korean hemorrhagic fever, is transmitted to humans from persistently infected mice (Apodemus agrarius), which serve as the primary reservoir. Various strains of adult Mus musculus domesticus (C57BL/6, BALB/c, AKR/J, and SJL/J) were prone to Hantaan virus infection when infected intraperitoneally.

First clinical signs were: -

1. Loss of weight

2. Ruffled fur

3. Reduced activity

4. Paralyses

5. Convulsions

Within 2 days of disease commencement, the animals died of acute encephalitis. PCR analysis indicated a systemic infection with viral RNA present in all major organs. To investigate the involvement of the interferon system in Hantaan virus pathogenesis, alpha/beta interferon receptor knockout mice are infected. These animals are more susceptible to Hantaan virus infection. They indicate an important part of interferon-induced antiviral defense mechanisms in Hantaan virus pathogenesis.

Introduction, Characterstics and Classification

Hantaan virus is a single stranded negative sense RNA virus from the family Bunyaviridae. It is from the genus Hantavirus. Its scientific name is Hantaan virus but it is often referred to as Korean hemorrhagic fever because the first known case happened in Korea around 1951. The virus was named Hantaan after a river in Korea. Hantaviruses are the only genera in the Bunyaviridae family that are rodent borne, the rest are arthropod-borne. Hantaviruses are enveloped, spherical in shape, and are approximately 90-120nm in size.

The virus attaches to host receptors though Gn-Gc glycoprotein dimer and is endocytosed into vesicles in the host cell. Replication and maturation of the virus occurs in the cytoplasm. Transcription is initiated by association of the L protein with the three nucleocapsid species. In addition to transcriptase and replicase functions, the viral L protein is also thought to have an endonuclease activity that cleaves cellular messenger RNAs (mRNAs) for the production of capped primers used to initiate transcription of viral mRNAs. As a result, the mRNAs of hantaviruses are believed to be capped and contain nontemplated 5' terminal extensions. The ribonucleocapsids migrate under the plasma membrane and buds, releasing the virion. Nascent virions are transported in secretory vesicles to the plasma membrane and released by exocytosis.