Discuss about the Zika Virus and Zika Virus Infection.
Zika virus came from the flavivirus borne from the mosquito emerged from the spondweni group which was at first identified in the monkeys of Uganda in 1947. Later in 1952, it was identified in the people living in Uganda along with Nigeria and gradually the virus covered the USA, Asia pacific countries, Arica, Tanzania and many other countries across the globe. In July 2015 Brazil identified a relation between Guillain-Barre disorder (GBS) and Zika infection; it damages the nervous system by the weakening of muscles affecting the immune system (Murray, 2016). In October 2015 Brazil also reported a relationship between microcephaly and Zika infection. More than 5600 cases of microcephaly reported in the year 2016 which is greater than 20 folds with respect to average o past five years.
Zika virus along with the Spondweni creates a sub-branch into the genus flavivirus which belongs to the flaviviridae family. It results in spondweni fever in human beings which is characterized by fever with symptoms of nausea, headache, chills, and discomfort. Sponwei virus was first identified in 1955 from mansonia uniformis mosquitoes which emerged from Lake Simbu which is situated in Spondweni region of South Africa (Murray, 2016). This virus as recently observed in sub regions of Saharan Africa and Papua New Guinea. Genes of this virus are made up of complex ssRNA molecules which is having two non-coding regions by analogy. It is a code for a polypeptide which is a combination of the capsid(C), envelope (E), precursor membrane (prM) and non-structural proteins (NS) (Murray, 2016). This coding is responsible for the recent outbreak in 2015. As per the recent reports published by WHO is widely spread in the Caribbean and Latin American countries. Although the virus came into existence 60 years back in Africa the awareness to cause possible threats was revealed in the recent years only. In many countries, the detection of this virus is due to the circulation of the travellers who are travelling from the countries where this virus is much active (Rawlinson, 2016). Recent reports say that in India three cases of this virus have been introduced through reverse transcription polymerase chain reaction (RT-PCR) by routine laboratory surveillance. It has been also reported that many sub-tropical and tropical regions in the world are at risk of this virus in the form of Chikungunya, yellow fever, and DENV (Joob & Wiwanitkit, 2017). Few studies suggest that since the year 2007 to march 2017 total 84 countries across the world is affected by this virus.
ZIKV is an icosahedral, single stranded, enveloped, positive sense RNA virus with the non-segmented genome. It is 40 nm in diameter having dense projection coated lipid envelope, which consists of a membrane and envelope glycoproteins having a dense inner core. Virions which are situated on the surface of cell membrane get entry into the host cell after which the mRNA transcription takes place (Joob & Wiwanitkit, 2017). Whenever the virus from the mosquito is transferred to the healthy human being it causes infection same is the case with the pregnant mother, if the virus gets transferred from mother to fetus then there are chances of an infant born with microcephaly.
Zika infection: a global threat to human population
Before 2015 ZIKV was not much in the notice as compared to another disease like EBOLA, influenza. Vomiting, headache, joint pains, rashes, red eyes all are the symptoms of this infection and is quite easy to detect as there is no specific therapy or vaccine available due to its treatable and mild symptoms. But these two factors have taken this virus in the notice (Wang, Wang & An, 2016). People did not gave much attention to this virus due to its low incidence and mildness of symptoms. There are two factors due to which ZIKV infection has emerged as a global issue for discussion.
In the year 1947, scientists detected this virus from the samples which were taken from a sentinel rhesus monkey in ZIKA forests, Uganda. The first proof of this infection was identified when a scientist fell ill while working on the strains collected from the mosquito; this discovered that this virus can be spread to human beings (Wang, Wang & An, 2016). ZIKA virus is spreading at an extraordinary speed, it has covered almost one fourth of the countries across the globe. Dengue and Chikungunya are also the infections which have emerged from this virus.
French and Brazilian countries have reported several incidences of spine malformation and congenital brain specially microcephaly. Transmission of this virus from mother to her fetus has resulted in microcephaly in infants which has to lead to the underdeveloped brain, leading to developmental retardation and it can also cause death in some cases (Weltman, 2016). There are different types of malformation due to infections, which have resulted in deaths but these cases are never linked with ZIKA virus. On December 8th, 2015 Brazil reported 1762 incidence of microcephaly whereas total 84 cases were reported in 2014. An infant born with microcephaly tested positive for ZIKA virus died on 28th November. This case created panic in people of Brazil; everyone was in fear due to this outbreak (Weltman, 2016). Many health organizations came into action and confirmed that there is an increase in the number of cases of disorders in central nerve system. These organizations advised people especially pregnant ladies to read about the symptoms of this virus and take preventive measures to keep them away from mosquito bites. Travellers were also warned that they should restrict their travelling to affected areas (Sorbera & Stringer, 2017).
Lack of vaccine. No proper research and common symptoms
Another reason is that there is no vaccination available for ZIKA virus as of now. Scientists are doing efforts to produce one, but testing and then producing a medicine takes years and is expensive also. The virus was occurring occasionally and no research was done for this (Spivak, 2016). only few people were researching on ZIKA virus and none of them were aware of the fact that how severe this virus is and it can spread how rapidly. Funding was being allotted to the research done on many other infectious diseases; people were not at all prepared to respond quickly to this virus. In the remote areas where there is a lack of resources and facility people did not pay much attention to ZIKA until WHO has interfered. Another reason was that it has similar symptoms to another infectious disease like Chikungunya, dengue and it is generally circulating in the same regions where the other infections are circulating. As it is almost impossible to prevent one from mosquito bites, WHO recommended pregnant ladies from not going to places where this virus is active and ladies who are planning to become pregnant should consult their doctors before visiting these places (Spivak, 2016). Lack of strong immunity system and research labs in remote areas can also be one of the reasons from spreading this disease.
Mild fever, skin rashes, red eyes, headache, joint pain, and conjunctivitis are the most common symptoms of ZIKA infection and they appear after 3-12 days of biting of mosquito. It can sometimes occur without symptom but often it has been observed that it has mild symptoms that can last up to 7 days. Severe symptoms which can lead to hospitalization are very rare (Sheng et al., 2017). ZIKA virus is transmitted by Ades Ageypti, a day biting mosquito. These mosquitoes are active during morning and late morning and evening. These mosquitoes also transmit the infection of yellow fever, Chikungunya, and dengue (Sheng et al., 2017). Whenever a female Ades Ageypti bites any human, a virus presented in the salivary gland gets injected of the infected mosquito into the wound where the anti-coagulants contained in her saliva facilitate feeding, and without knowing the male mosquito also injects the ZIKA virus into the host. There is another way through which the infection is transmitted from mother to fetus and when the child is born he suffers from the underdeveloped brain (Du, Zhou & Jiang, 2017). Sexual transmission is also one of the ways through which the infection is transferred from the male to female or vice versa. Blood transfusion through organ transplant also results in the transmission of infection (Sheng et al., 2017).
Currently, there are no such medication and vaccines available for this virus, your immune system is the best cure available till now but one can take precautions:
- From mosquito bites- prevention from mosquito bites is the key measure to avoid this virus from spreading. Using mosquito repellents, wearing full sleeves clothes, screened windows will minimize the risk of affecting the virus. It is very much important for children and old people to take precautions because there immune system is weak. People who are travelling must avoid going to places which are affected from ZIKA and pregnant ladies, if any has been infected by this virus then she should be immediately taken to hospital as this infection is transmissible and can affect her fetus (Slavov, Otaguiri, Kashima & Covas, 2016). It is very much critical to prevent breeding of these mosquitoes in houses as they breed and reproduce in stagnant water bodies, so one must ensure to cover all the water filling containers and empty waste water and sprinkle the pesticide timely to prevent breeding of mosquitoes.
- Through sexual transmission- transmission through sexual activities has been confirmed by many labs. In order to prevent one from the risk of sexual intermission and pregnancy complications due to ZIKA virus contamination, one should indulge in safe sex or avoid sexual activities during pregnancy if the partner is affected by ZIK infection (Gruber & Krause, 2017). If anyone has come from the area which is affected by the virus then he should avoid sexual intermission at least for 8 weeks although if there is no symptom found.
ZIKV Recent epidemic status/ Role of agents
In the year 2015 Brazil and panama have reported many cases of microcephaly; Colombia has also joined the league by detecting few cases which are linked with Zika virus. In other countries, there are not enough research and evidence to prove the link of this case with Zika. After the outbreak, Brazil has seen 20 times rise in the cases of the Zika infection where babies are born to an infected mother with microcephaly (Slavov, Otaguiri, Kashima & Covas, 2016). This virus is currently active in 38 countries and gradually increasing in other countries by affecting infants causing fetal malformation and nervous disorders. If this goes beyond control then it will be a serious health catastrophe for the world. Looking after this condition many health organizations have identified that there is an urgent need Point of Care Testing (POCT (Slavov, Otaguiri, Kashima & Covas, 2016)). At present, there are 30 companies who are working on it and have developed an advanced version of diagnostic tests. For vaccines total 23 proposals are being worked on by around 14 vaccine developer companies located in India, France, Australia, and the US. Since these vaccinations are being prepared for the pregnant ladies and the women of child bearing age, it must fulfil high standards of safety (Zea-Vera & Parra, 2016). Potential results of five new tools of mosquito control are also being tested by many experts among whom no one qualified for full scale implementation. Some Brazilian experts were in doubt that Zika alone is responsible for microcephaly or there are other factors which to be held responsible for the birth defects. As on 5th August 2016 total of 185 travellers cases, two pregnant mother cases, and one sexually transmitted case have been detected in Canada (Zea-Vera & Parra, 2016).
Traditionally, there is a TORCH agent which has four characteristics consisting of mild illness in the mother who is infected, transmission of virus to fetus vertically, development of various anomalies in the fetus and in some cases maternal therapy therefore this should be considered as a severe TORCH agent which is threatening public health.
There are many types of research on Zika virus vaccination but none of them made it to he market. The target population is pregnant women and women bearing the age of the child so it should be safe and effective. Only effective DNA vaccines would be preferred rather than vaccines which are made out of weakened Zika virus to ensure safety measures (Zea-Vera & Parra, 2016). The increasing number of cases which are affected by the virus is an alarming situation so there is an urgent need for production of vaccines.
- Clinical trials- few of the best clinical trials used were mice, rhesus macaques and then human. Three different types of investigational vaccines were used, DNA based vaccine, inactivated virus vaccine and adenovirus vector based vaccines. Each of the three trials holds the possibility of designing effective Zika vaccine (Gowder, 2016).
- Efforts with mouse model- research were conducted on mice and reported six different Zika virus antibodies out of which four neutralized the strains of mosquitoes transmitted from Africa, Asia, and America. NIAID supported team x-ray crystal images of these four antibodies and extracted Zika proteins which could be beneficial in producing vaccines (Martins, Dye & Bavari, 2016). DNA vaccine or purified inactive virus vaccine provides complete safety in mice against zikv in single immunization (Gowder, 2016).
- Efforts with rhesus macaques- the above testing of inactivated Zika virus vaccine were also done on 16 rhesus macaques. These animals were two injections continuously for four weeks after which they did not show any symptom of Zika virus another experiment was also done in which researchers administered two doses of an experimental DNA and one dose of adenovirus vector vaccine to three different groups of four monkeys each. These monkeys were then kept in contact with Zika virus for four weeks (White et.al, 2016). Both DNA and adeno virus vaccines provided complete protection from infection. Both of them protected from infection, boost the immune system and had no adverse side effect of vaccines. But due to the huge gestational difference in rhesus macaques and human this experiment needs to be done on a human to provide vaccines (Takasaki, 2016).
- Efforts with human testing- the NIAID and NIH performed this test on 80 healthy candidates between the age of 18 to 35 years. DNA vaccine was considered for the clinical trial in human. The first stage will identify the response of immune system to the vaccine (Takasaki, 2016). Two new technologies including synthetic pieces of DNA and electric pulse to open immune cells were considered so that they take up vaccines better. As a result, these vaccines were found safe and immune system was also responding well. DNA or gene based vaccinations provides strong and durable protection against disease (Takasaki, 2016). Phase 1 of this research is still under process once the results show a positive outcome, the second phase will start. US government has distributed a license to use these vaccines and materials all over the world for research purpose (Du, Zhou & Jiang, 2017).
GLS-5700 the inovio Zika product is called DNA vaccine. In this vaccine, there is a protein inbuilt that encircles the Zika virus. The site where injection has been injected is damaged using a device that passes an electric pulse which guides DNA into the cells into the cells through a process called electroporation (Nilika & Kamboj, 2016). The cells then the instruct immune system to consider Zika virus as foreign invader which needs to be attacked using antibodies to fight against it. Several researchers and scientists are in competition to develop the vaccination for Zika virus but there is a group of scientists who have found 24 FDA approved drugs which have shown some potential to block Zika from infecting human cells. Few of the drugs which are used for treating cancer and depression have also shown some positive signs of curing Zika virus in pregnant women (Nilika & Kamboj, 2016). These researchers initially took 774 drugs out of which 24 were found effective. Now, these drugs are being used for further studies to develop vaccines against Zika virus from spreading.
Zika virus is an infection which has come from mosquito bite generally in the day time. It has very mild symptoms and was first discovered in the year 1948.among all the countries Africa is said to be the most affected country from this virus followed by south and North America. The main reason for this global emergency is its link with congenital birth defects to an infected mother and lack of vaccines available due to very limited researches done (Nilika & Kamboj, 2016). Another reason is the absence of population immunity. As there are no vaccines available for this infection WHO has advised people to stay at home and prevent themselves from these mosquito bites. It is the only option left with people to take corrective measures like use mosquito repellent, use screened glass, wear full sleeves clothes by this way they can prevent themselves from biting of mosquito (S, 2017). Specially pregnant ladies must take cares if they are affected then there is cancer that it can affect their baby also which can cause congenital birth defects in the baby in the form of underdeveloped brain or weak muscles or damaged nervous system. Other prevention can also be taken by cleaning the house properly and don’t let the mosquitoes breed. Tremendous information is available on the research being done on the Zika virus, but says now there is no such vaccine came out which can prevent humans from this virus (S, 2017).
This virus is currently active in 38 countries and gradually increasing in other countries by affecting infants causing fetal malformation and nervous disorders. If this goes beyond control, then it will be a serious health catastrophe for the world (Maslow, 2017). So keeping this in mind various health organizations have issued information on how to prevent themselves from this infection and what are the possible symptoms through which one can identify that they are suffering from this infection (?ahiner, 2016). Mild fever, headache, reddish eyes, rashes on the skin are some of the symptoms, but these symptoms are somewhat same as of Chikungunya, yellow fever, and dengue. Many countries are working on identifying the correct vaccination for this infection, which is safe and secure for pregnant women, but till now no such product has come up in the market (?ahiner, 2016). The target population is pregnant women and women bearing the age of the child so it should be safe and effective. Only effective DNA vaccines would be preferred rather than vaccines which are made out of weakened Zika virus to ensure safety measures.
The increasing number of cases which are affected by the virus is an alarming situation so there is an urgent need for production of vaccines. It is up to humans how they prevent themselves from this infection, numerous information has been provided by the health organizations now depends on us, how do we use this information and prevent ourselves and our family and surrounding (S, 2017). It is an alarming situation in the world and it is high time now that they should seriously act on it and produce vaccines which can prevent this disease.
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