Review on the Zika virus.
Introduction.
The species of the Zika Virus belongs to the genus Flavivirus and a virus family Flaviviridae. The Zika Virus is known to be spread by day by the active Aedes mosquito species. The name Zika Virus originated from the Ugandan forest, Ziika forest, where it was first isolated in the early years of 1947. This type of virus has been notably related to the Yello fever, dengue fever, and the West Nile viruses. ( Vizjak, A. (2016).
Zika virus. (ZIKV)
The virus causes Zika fever, which is associated with mild symptoms, and up to date, there is no known treatment. Similar to the other viruses, the ZIKV is enveloped and icosahedral with a non-segmented, single-stranded positive-sense Ribonucleic Acid genome. The positive sense RNA is easily translated to the viral protein
The RNA genome is responsible for the encoding of seven nonstructural protein and other three structural proteins. Amongst the structural proteins, one of it encapsulates the virus. The protein which is now the flavivirus envelop glycoprotein is responsible for spaning the endocytosis since it binds to the endosomal of the organism’s membrane. The replication of the viral genomes is dependent on the production of the double-stranded ssRNA(+) genome, which simultaneously followed by transcription and its replication to form mRNAs and the ssRNA(+) viral genome.
After the hosts are infected, research shows that within the first six hours of infection, the mitochondria and the vacuoles in the cells begin to swell. ( Vizjak, A. (2016). This consequently leads to the death of the cell, paraptosis. The transmembrane protein, IFITM3, protects the cells from attack by a virus. Therefore, the cell with low IFITM3 is at risk of being easily infected.
Where is the Zika virus found and how is it spread.
This species of virus can be found all over the world, especially in tropical areas. The virus is recorded to have first been isolated in Ziika forest which is located in Uganda, Africa. Though it was first located in Africa, its outbreak has severally happened in southern and southeastern parts of Asia, America and the parts of the Pacific islands.
The Zika virus is known to be spread by the bite of the Aedes species mosquitoes, Aedes aegypti, and Aedes albopictus. The mosquito is reported to be found all over the world. When this mosquito bites an infected person, the Zika virus enters the mosquito. If the mosquito bites a healthy person, the virus from the mosquito enters the blood of the healthy person leading to infection.
The virus has also been known to be spread from the pregnant mother to the fetus during pregnancies.
Sexual contact has also been recorded to transmit the virus from an infected person to a healthy person if protective measures such as condoms are not used. ( Timofeev, J. (2016).
In hospitals, apart from the spread by mosquito, blood transfusion of unscreened blood can also lead to the spread of the virus.
What are the virulence factors of the Zika virus?
There are two lineages of the virus, which are the African lineage and the Asian lineage. Therefore, over time, research has shown that mutations acquired during the flavivirus evolution have resulted in differences in their virulence factors or the tropism factors.
African strain of ZIKV has been known to be widely spread by the Aedes aegypti species of mosquito, therefore, increased infection.
The Asian strain has been recorded to replicate a5t deficient levels in tissues of the host, therefore the virus able to survive undetected for a very long time. This strain has been known to cause prolonged infections as compared to the African lineage virus. The African strain is aggressive and known to cause cell death within a very short time.
The African strain has a higher infection rate and likely to cause the fast death of many cells within a short time. The symptoms are exhibited very early after infection, unlike Asian strain, which takes a rather longer period to replicate.
The Asian strain can cross the placental barrier earlier during the gestation period hence leading to microcephaly inhuman. The brain does not develop, which may lead to stillbirth. It is also associated with congenital infection and vast neurological disorders. ( Timofeev, J. (2016).
The African strain has a higher inflammatory rate of the cytokinesis (such as tumor necrosis factor). Therefore the African strain has a higher virulence than the Asian strain.
Which are the symptoms and the incubation period of the
Zika virus infection.
The incubation period between infections to the first signs is three to fourteen days.
Though the majority of people infected with Zika virus do not show signs.
If the symptoms are to be presented, they are generally mild. The symptoms include
Fever
Malaise.
Mild headache.
Conjunctivitis.
Muscles and pain in the joints.
Rash.
The signs and symptoms last for one to seven days.
Diagnosis of the Zika virus infection.
The diagnosis of the virus can be suspected on the basis if a person living in an area prone to Zika virus spread starts to show the mild signs. This is not a conclusive diagnosis; therefore, blood or other blood fluids is taken to the lab for analysis.
How does the virus affect different organs in an organism?
The Zika virus directly attacks the brain cells. The virus consequently attacks the immune system detection system of the brain. The neural progenitors can also be invaded by a ZIKV strain killing some of the neural progenitors but not all. The surviving cells continue to replicate the ZIKV virus for many weeks.
How does the immune system respond to the ZIKV infection?
When the brain attacks the brain cells, it invades the immune system, and therefore, the virus hinders the stimulation of the immune system response.
The current treatment plan of ZIKV and its success.
There is no known treatment for the Zika virus and only prevention techniques. No vaccine or medicine have been found for the ZIKV.
The doctors only treat symptoms such as headache, fever, or malaise.
What population is at the risk of infection.
The virus can infect any person at any age but if also prone to infect the unborn newborns.
The Zika virus is known to affect the fetus and very young children whose brain is not entirely developed. It is known to lead to blindness, seizures, and other congenital disorders. ( Petersen, L. R. (2016).
In adults, the virus is known to cause paralysis (Guillain-Barre)
The environments and sources associated with the Zika virus.
The virus is transmitted by the Aedes species of mosquito, and therefore in areas with stagnant water or long grasses that can harbor the mosquito and contribute to its multiplication, these areas are prone of having the pandemic of the ZIKV infections. The virus was first reported in Uganda but has spread all over the world and recently reported in southern Asia where there was an outbreak. (Zin, A. A. (, 2016).
An environment that can ensure multiplication of the Aedes species mosquito can have an outbreak of the ZIKV infection.
What is the prognosis of the infection caused by ZIKV?
The incubation period until the first sitting of symptoms is roughly between two to twelve days. Different people may exhibit different signs, or in most cases, no symptoms are visible at all. The infections are self-limiting, whereby the signs last for only seven days. The mild signs may be a headache, fever, a rash, joints may also experience some pains and also nonpurulent conjunctivitis. The infection leads to complication since it is linked with neonatal deformities and neurological disorders. ( Petersen, L. R. (2016).
Prevention.
The ZIKV does not have any known medicine or vaccination. Therefore, the public and the health institution should direct their effort in preventing the spread of the virus. The virus is at many times spread by an Aedes species mosquito. Therefore it is paramount to protect oneself from mosquito bites.
Also, the hospitals should screen the blood before transfusing to avoid the spread of the virus.
Sexually active individuals should always practice protective measures during sexual contact.
Conclusion
The Zika virus is a vector virus which is spread during the day by Aedes species. The virus was first reported in Ziika forest but later spread all over the world. There is no known vaccination or medicine for the ZIKV infection. Therefore it is paramount to prevent the spread of the virus by clearing stagnant water and clearing bushy areas to avoid breeding of mosquitos. ( Vizjak, A. (2016). It is also essential to prevent oneself from a bite by sleeping under a treated net or using mosquito repellants.
References.
Mlakar, J., Korva, M., Tul, N., Popović, M., Poljšak-Prijatelj, M., Mraz, J., … & Vizjak, A. (2016). Zika virus associated with microcephaly. New England Journal of Medicine, 374(10), 951-958.
Petersen, L. R., Jamieson, D. J., Powers, A. M., & Honein, M. A. (2016). Zika virus. New England Journal of Medicine, 374(16), 1552-1563.
Musso, D., & Gubler, D. J. (2016). Zika virus. Clinical microbiology reviews, 29(3), 487-524.
Rasmussen, S. A., Jamieson, D. J., Honein, M. A., & Petersen, L. R. (2016). Zika virus and congenital disabilities—reviewing the evidence for causality. New England Journal of Medicine, 374(20), 1981-1987.
Gourinat, A. C., O’Connor, O., Calvez, E., Goarant, C., & Dupont-Rouzeyrol, M. (2015). Detection of Zika virus in urine. Emerging infectious diseases, 21(1), 84.
Zanluca, C., Melo, V. C. A. D., Mosimann, A. L. P., Santos, G. I. V. D., Santos, C. N. D. D., & Luz, K. (2015). First report of autochthonous transmission of Zika virus in Brazil. Memórias do Instituto Oswaldo Cruz, 110(4), 569-572.
Brasil, P., Pereira Jr, J. P., Moreira, M. E., Ribeiro Nogueira, R. M., Damasceno, L., Wakimoto, M., … & Zin, A. A. (2016). Zika virus infection in pregnant women in Rio de Janeiro. New England Journal of Medicine, 375(24), 2321-2334.
Driggers, R. W., Ho, C. Y., Korhonen, E. M., Kuivanen, S., Jääskeläinen, A. J., Smura, T., … & Timofeev, J. (2016). Zika virus infection with prolonged maternal viremia and fetal brain abnormalities. New England Journal of Medicine, 374(22), 2142-2151.