Dengue virus was first discovered in Japan by Susumu Hotta with his coworker Ren Kimura in 1943. Like all other viruses, the Dengue virus is also a Microscopic organism that is alive and can multiply just inside a human being (obligate intracellular organism). Dengue Viruses belong to arthropod-borne Virus (arboviruses) means spread through arthropods. Viruses were first isolated by Albert B. Sabin and Walter Schlesinger after the discovery. They gave the name DEN-1 virus (DENGUE VIRUS 1). The question arises here: Is DEN-1 the only type of dengue virus?
Currently, there are four serotypes of Dengue all over the world such as DEN-1, DEN-2, DEN-3, and, DEN-4. These serotypes act differently because they all are almost similar but different in genetic variation. The most important thing to be noted is these all serotypes cause almost the same dengue fever in all human beings.
Structure of dengue virus:
Viruses have unique structures and almost every virus is the same on the basic level. Dengue virus is an Enveloped Virus belonging to the Genus Flavivirus and has a positive-sense single-stranded RNA genome. This genome has 10 proteins which are divided into structural and non-structural proteins.
3 of the structural proteins are Envelope, Capsid and, Membrane protein whereas 7 of the proteins are named NS1, NS2A, NS2B, NS3, NS4A, NS4B, and, NS5 are the nonstructural proteins. These non-structural proteins help in viral assembly during the replication process.
Transmission of the virus; Replication of virus
A virus needs a host cell to replicate. Dengue virus also just needs a host body to replicate in it. Dengue virus is transmitted through arthropods. It spreads through the bite of female Aedes species mosquitos. (Aegypti or albopictus). This mosquito also spread Zika and Chikungunya virus. The mosquito lays eggs in standing fresh water such as in buckets pots or drums. Etc.
These viruses also lay eggs in flowerpots that are filled withhold water. These mosquitos bite a healthy person and cause them Dengue. The transmission also happens from mother to offspring as the virus can pass through the fetus. It is a rare chance that this virus can spread through blood-to-blood contact.
Dengue virus replicates in human body cells known as fibroblasts. This also attacks Langerhans present under the skin. The virus enters the cell through the presence of receptors called Heparan sulfate proteoglycan receptors by the process of Endocytosis. The virus enters in cell and releases Its Single-stranded RNA and translation of the negative strand takes place.
These Strands serve as a template for positive-sense RNA synthesis. Multiple copies of the Positive strand formed and were covered up by the viral capsid. This process takes place at Endoplasmic Reticulum and Golgi complex in the cytoplasm. These multiple copies are released out through exocytosis.
Clinical Features:
Flavivirus tends to give different types of Clinical features so Dengue fever Symptoms are distributed into 3 subcategories:
- Mild Symptoms:
The first and foremost symptom of the Dengue virus is Fever followed by a rash known as Dengue rash on the body.
- Severe and Warning symptoms:
Sometimes cause meningitis and encephalitis. A person has vomited three times a day, has Abdomen pain, feels tired and miserable, and has Bleeding Gums and nose. (Most of the symptoms of bacterial and viral conditions are the same such as fever, abdomen, vomiting in hepatitis, and dengue with same as in typhoid and malaria).
- Dengue Hemorrhagic Fever:
Most wild symptoms of the Dengue virus persist when a person fails to treat dengue. This fever may affect any of the body’s organs too; they also affect body immunity so they can defend the body from this viral disease. This is a life-threatening illness.
- Dengue fever can sometimes become Classic Dengue Fever (break-borne Fever). It commonly starts with flu-like symptoms, such as a temperature, retro-orbital discomfort, and a headache. Muscle and joint pain are among the most severe symptoms (break-borne). Leukopenia and enlarging lymph nodes are prevalent.
Laboratory diagnosis:
Viruses are difficult to diagnose during their latent face as they are considered in the sleeping phase. As the viremic period starts the patient show symptoms of the particular viral disease so a doctor may advise having a diagnostic test. As I said earlier mostly viral and bacterial symptoms are the same so the doctor clearly observes the symptoms and prescribes accordingly. The following are the most important diagnostic tests are performed for dengue virus diagnoses.
- RT PCR: RT PCR is used to detect the viral load of RNA.it is the most important test to follow up with the patient in the acute stage of Dengue.
- Serology: Detecting the special type of IgM Antibody that is present in the patient having a recent dengue attack. IgG titer is also recommended in most cases.
- Blood CP or Blood CBC is recommended almost daily to check thrombocytopenia and leukopenia as the patient with dengue face a lot of decrease in Platelets.
- Sometimes Patient LFT is also used as a diagnosis. Patients having chronic Dengue fever will have raised AST and ALT.
- Dengue specific Antigen and antibody (ELISA).
Prevention:
There is no dengue fever vaccine or antiviral drug that can prevent Dengue, So prevention must be done by controlling the spread of the virus and also by checking up on Dengue fever symptoms regularly.
- The use of insecticides is mandatory, especially in places where mosquito eggs are present like pots, flower pots, and water buckets.
- Eat plenty of food and vegetable.
- Uses of mosquito repellent are important and wear clothes that cover the whole body.
- Increase liquid intake during the affected period such as juices, lemon, and citrus food
An overview of Dengue Virus:
|
Virus |
Structure |
Serotypes |
Transmission |
Cause |
Symptoms |
Prevention |
|
Dengue virus |
+ SS RNA virus with spherical and icosahedral symmetry |
Four serotypes DEN-1 DEN-2 DEN-3 DEN-4 |
Through the bite of the female Aedes mosquito, through the placenta |
Dengue fever, Dengue hemorrhagic Fever, and Break borne fever. |
Headache, fever, dengue Rash, Vomiting abdomen Pain, bleeding gums and nose. |
No antiviral drugs and no vaccines are available. |
FAQs
What causes Dengue?
Dengue virus is transmitted through arthropods. It spreads through the bite of female Aedes species mosquitos. (Aegypti or albopictus). This mosquito also spread zika and the Chikungunya virus. The mosquito lays eggs in standing fresh water such as in buckets pots or drums. Etc.
What are the first signs and symptoms of Dengue?
The first and foremost symptom of the Dengue virus is Fever followed by a rash known as Dengue rash on the body. Severe symptoms include Abdomen pain, vomiting, feeling tired and miserable, and Bleeding Gums and, nose.
How to prevent dengue fever?
- Use of insecticides is mandatory during the outbreak, especially in places where mosquito eggs are present like pots, flower pots, and water buckets.
- Use mosquito repellent is important and wear clothes that cover the whole body.
- Increase liquid intake during the affected period such as juices, lemon, and citrus food.
Doctors and Researchers Opinion:
There are more than 75 viruses in the genus Flavivirus (53 species), with roughly 30 of them being medically important dengue outbreaks that have affected Earth quite efficiently as numerous rise in cases found in both America and South Asia. According to CDC 40 percent of the population of world are at risk of Dengue fever.
Dengue fever is frequent in Puerto Rico, the US Virgin Islands, and American Samoa, all of which are US territories. Almost all of the dengue fever cases recorded in the 48 contiguous US states were caused by tourists who had been infected abroad. In 2010, NIH tells us about how the Virus infects a healthier cell with complete information which is important research in the history of virology.