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Virology Dengue - Dengue Virus in Detail
Dengue is a mosquito-transmitted virus, primarily affecting tropical and subtropical regions, and is the leading cause of arthropod-borne viral diseases worldwide. The virus has four main serotypes and is transmitted mainly by the Aedes aegypti mosquito, leading to symptoms like high fever, severe headaches, and joint pain. There is no specific treatment for dengue, and prevention focuses on reducing mosquito populations and avoiding bites.
Virology Dengue - Dengue Virus in Detail
- 1. z K. Gayathri BP231506 1stM.Sc Microbiology Deparment of Microbiology Sacred Heart College (Autonomous), Tirupathur Dengue Virus
- 2. z Introduction Dengue isa mosquito-transmitted virus and the leading cause of arthropod-borne viral disease in the world. It is also known as breakbone fever due to the severity of muscle spasms and joint pain, dandy fever, or seven-day fever because of the usual duration of symptoms. Dengue is found in tropical and subtropical climates, mostly in urban and semi-urban areas. It's a problem in many tropical and subtropical parts of the world, including Africa, Asia, South America, and some parts of northern Queensland In 1943, Ren Kimura and Susumu Hotta first isolated the dengue virus while studying blood samples of patients taken during the 1943 dengue epidemic in Nagasaki, Japan.
- 3. z Dengue Virus Denguevirus (DENV) is a single-stranded, positive-sense RNA virus that belongs to the Flaviviridae family. It's an enveloped virus with 10,700 bases. DENV is a member of the Flavivirus genus, which also includes other arthropod-borne viruses like Zika, West Nile, and yellow fever DENV is transmitted by the bite of Aedes mosquitoes. It's categorized as an arbovirus (arthropod-borne virus) because it's transmitted by mosquitoes.
- 4. z Structure Dengue virus is40-60 nanometers in size, with an isometric nucleocapsid of 25- 30 nanometers. The dengue virus's structure is roughly spherical, with a diameter of approximately 50 nanometers.
- 5. z Types of DengueVirus The four dengue virus serotypes are DENV-1, DENV-2, DENV-3, and DENV-4. They are called serotypes because each has different interactions with the antibodies in human blood serum. In 2013, a fifth variant, DENV-5, was isolated. This serotype follows the sylvatic cycle unlike the other four serotypes which follow the human cycle
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- 7. z Replication The replication cycleof the dengue virus (DENV) includes the following steps: 1. The virus binds to host cell receptors. 2. The virus enters the host cell via receptor-mediated endocytosis. 3. The virus is internalized into a clathrin-coated endosome. 4. The viral genome is transported to the endoplasmic reticulum (ER). 5. The viral genome is replicated and viral proteins are synthesized. 6. The viral proteins are assembled into a nucleocapsid. 7. The virus matures and egresses. 8. The newly synthesized dengue viruses are released and go on to infect other host cells.
- 8. z Pathogenesis Infection of DendriticCells Dengue virus enters dendritic cells in the skin via mosquito bites. Dengue virus (DENV) can directly induce DC-apoptosis through replication inside infected cells
- 9. z Pathogenesis Dissemination via Lymphatics The virus then disseminates via the lymphatics to other tissues. After a mosquito bite, cells in the skin are infected and deliver Dengue virus (DENV) to the draining lymph nodes. The lymph nodes contain resident macrophages and other unknown cells. These cells infect and deliver the virus to the lymphatic and vascular system, which can lead to the infection of bone marrow
- 10. z Transmission 1. Mosquito Bites The dengue virus is spread through the bite of an infected female mosquito, primarily the Aedes aegypti mosquito. Other species within the Aedes genus can also act as vectors, but their contribution is secondary to Aedes aegypti. 2. Blood Transfusion The virus can be transmitted through blood transfusion or organ transplantation.
- 11. z Clinical Symptoms 1. Fever:A high fever of 104°F (40°C) 2. Headache: A severe headache 3. Pain: Pain behind the eyes, muscle, bone, or joint pain, or extreme aching in the legs and joints 4. Rash: A rash that appears two to five days after the onset of fever 5. Other symptoms: Nausea, vomiting, fatigue, swollen glands, leukopenia, and a positive tourniquet test
- 12. z Laboratory Diagnosis 1. Serologicaltests - ELISA 2. Molecular tests - PCR 3. Complete blood count 4. Electrolyte test (including Na+, K+, Cl-) 5. Liver function tests (including AST, ALT, GGT) 6. Albumin test Treatment There is no specific medicine to treat dengue fever.
- 13. z Prevention 1. Eliminate MosquitoBreeding Sites 2. Use Mosquito Repellents 3. Wear Protective Clothing 4. Mosquito Nets 5. Stay Indoors during Peak Mosquito Activity
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