Everything you wanted to know about Zika virus

The World Health Organization (WHO) expects that Zika virus, a mosquito-borne disease, spreading through the Americas, to affect between 3 million and 4 million people. Let’s analyse this in brief!

Where was the first Zika virus outbreak identified?

  • Zika virus is an emerging mosquito-borne virus that was first identified in Uganda in 1947 in rhesus monkeys through a monitoring network of sylvatic yellow fever.
  • It was subsequently identified in humans in 1952 in Uganda and the United Republic of Tanzania.
  • Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Asia and the Pacific.

Trivia : Do you know why is it called Zika Virus?

It was first isolated from Rhesus monkeys in Zika forest near Lake Victoria in Uganda.

Find Out why was Ebola virus named as such?


 

What makes this outbreak different?

  • The current outbreak, the first ever in the western hemisphere, is a big deal for a number of reasons
  • We now know that it’s not adults who have the most to lose but their unborn babies
  • Microcephaly is a condition where a baby is born with an abnormally small head and brain defects
  • Worldwide it affects only 1 in 30,000 to one in 250,000 newborns
  • In Brazil there are usually a few hundred cases annually at most, but since October 2015, there have been 3,500 new microcephaly cases

But, what is microcephaly?

  • Microcephaly is a rare condition where a baby has an abnormally small head.
  • This is due to abnormal brain development of the baby in the womb or during infancy.
  • Babies and children with microcephaly often have challenges with their brain development as they grow older.
  • Microcephaly can be caused by a variety of environmental and genetic factors such as Downs syndrome; exposure to drugs, alcohol or other toxins in the womb; and rubella infection during pregnancy.

How does the Zika virus spread?

  • Zika virus is transmitted to people through the bite of an infected mosquito from the Aedes genus, mainly Aedes aegypti in tropical regions
  • This is the same mosquito that transmits dengue, chikungunya and yellow fever
  • Zika virus disease outbreaks were reported for the first time from the Pacific in 2007 and 2013 (Yap and French Polynesia, respectively), and in 2015 from the Americas (Brazil and Colombia) and Africa (Cape Verde)

How bad is it now?

  • As of January 23, 2016, the Zika virus has spread to 21 countries and territories of the Americas
  • It’s speculated that the virus must have arrived in Brazil along with the throngs that swept in during the 2014 FIFA World Cup
  • Things look so grim that governments of 4 South American countries are now advising women to not get pregnant until the situation is brought under control
  • The WHO has predicted that the virus is likely to spread all over North and South America, except for Chile and Canada where the Aedes aegypti mosquito is not present
  • The reason that the WHO thinks these countries are so susceptible is that their populations have not been exposed to the virus before and hence have no immunity

Is there a cure?

  • No, there isn’t. There exists medication for symptomatic relief but these are quite useless now that we know about the microcephaly link
  • Research on the Zika virus is still quite primitive
  • Given its generic symptoms in adults, it’s very easy to miss or misdiagnose
  • Moreover, the virus doesn’t seem to show effects in common lab animals like mice and rats. Getting monkeys is extremely tough because of restrictions on primate research
  • Vaccine development and antiviral drug discovery efforts are on but this takes time, and with the Zika virus, we’ll be starting from scratch

Does Brazil have a way out?

  • Brazil needs an immediate plan of action for more than one reason
  • Rio de Janeiro is frantically spraying insecticides at the parade grounds where the annual carnival celebrations will commence soon
  • In August, the city is due to host the Olympics

What about India?

  • India is one of the Aedes aegyptis’s many homes but the Zika virus itself has not ever been detected in our country so far
  • However, in a study in the 1950s, healthy individuals from 6 Indian states showed passive immunity to the virus
  • This means that though their blood contained antibodies against the virus, this was not because they were exposed to the virus
  • Usually passive immunity is acquired through vaccines, from mother-to-child transmissions or breast milk
  • In the case of India, where the Zika virus is not known to exist, the antibodies probably arose from exposure to similar viruses
  • Nevertheless, theoretically, Zika can spread anywhere that the mosquito exists
  • That means India, too. Indians are just as susceptible if they travel to high-risk countries

 

Is there something more that you wanted to know which we did not answer yet? Drop in with your questions.

 

Published with inputs from Arun | Image - Outbreaknews

Any doubts?


  1. Profile photo of Karan Sandhu Karan Sandhu

    Zika drug breakthrough-
    Tang, along with Johns Hopkins Professors Guo-Li Ming and Hongjun Song and National Institutes of Health scientist Wei Zheng identified two different groups of compounds that could potentially be used to treat Zika — one that stops the virus from replicating and the other that stops the virus from killing fetal brain cells, also called neuroprogenitor cells.

    One of the identified compounds is the basis for a drug called Nicolsamide, a U.S. Food and Drug Administration approved drug that showed no danger to pregnant women in animal studies. It is commonly used to treat tapeworm.

  2. Profile photo of Rohit Pande Rohit Pande

    Latest update on this – Desi company makes a med for this!

    And interesting reason as to why they started doing this –

    We have been working on Zika vaccine for last more than 15 months. The reason we are working, because we have been working on Chikungunya vaccine. We have made a vaccine, which is under clinical trial. We have got two patterns. So, we thought if Chikungunya comes to India, then what is next. So, naturally the same mosquitoes, which transmit Chikungunya, is likely to bring Zika. That’s how we started working on Zika vaccine.

    http://www.business-standard.com/article/news-ani/bharat-biotech-claims-to-have-developed-world-s-first-zika-vaccine-116020301434_1.html

  3. Profile photo of Pankaj Solanki Pankaj Solanki

    a new topic to study….hussssshhhh

  4. Profile photo of Simran Bains Simran Bains

    Scary this is!! New and strange diseases coming. No vaccine developed. Jesus 🙁

A life of struggle for Zika-affected families

  1. In November 2016, the World Health Organization lifted its emergency designation from the mosquito-borne virus, but Zika has hardly disappeared
  2. For families of Zika babies, the disastrous effects are only deepening
  3. Many babies also have a long list of varied symptoms, leading experts to rename their condition “congenital Zika syndrome
  4. They can have seizures, breathing problems, trouble swallowing, weakness and stiffness in muscles and joints preventing them from even lifting their heads, clubbed feet, vision and hearing problems, and ferocious irritability
  5. While the children are still small enough to be held, fed and carried, ultimately, many may be unable to walk, attend regular schools, or live on their own as adults

 

GM mosquito trials to control dengue, chikungunya launched

  1. What? Outdoor caged trials to demonstrate the efficiency of genetically modified mosquitoes to suppress wild female Aedes aegypti mosquito populations that transmit dengue, chikungunya and Zika were launched in Dawalwadi, Badnapur, in Maharashtra’s Jalna district
  2. The trials use the Release of Insects carrying Dominant Lethal genes (RIDL) technology
  3. The efficiency in lab trials to kill offspring was over 99% and male mosquitoes imported from the U.K were able to mate with locally available wild female mosquitoes and the longevity of imported mosquitoes was the same as the wild ones
  4. Vector Control: The technology uses genetically modified male Aedes aegypti mosquitoes that carry a dominant lethal gene
  5. When male GM mosquitoes mate with wild female mosquitoes the lethal gene is passed on to offspring
  6. The lethal gene in the offspring kills the larvae before they reach adulthood
  7. Since male mosquitoes do not bite humans, the release of GM males will not increase the risk of dengue, chikungunya and Zika

Note4students:

This is very important for prelims. Know about the Vector Control Technology.

Back2basics:

What is Vector Control Technology?

  1. Vector control is any method to limit or eradicate the mammals, birds, insects or other arthropods (here collectively called “vectors”) which transmit disease pathogens
  2. The most frequent type of vector control is mosquito control using a variety of strategies
  3. Several of the “neglected tropical diseases” are spread by such vectors
  4. For diseases where there is no effective cure, such as Zika Virus, West Nile Virus and Dengue fever, vector control remains the only way to protect human populations
  5. As many vector control methods are effective against multiple diseases, they can be integrated together to combat multiple diseases at once
  6. The World Health Organization therefore recommends “Integrated Vector Management” as the process for developing and implementing strategies for vector control
    http://www.thehindu.com/sci-tech/health/GM-mosquito-trials-to-control-dengue-chikungunya-launched/article17093840.ece

Zika alert in India

  1. Alert! The Indian Medical Association (IMA) has issued a Zika alert in the country
  2. Context: Local mosquito transmission of Zika virus infection has been reported in Singapore
  3. Local mosquito transmission: Mosquitoes in the area are infected with the Zika virus and are spreading it to humans
  4. IMA: Asked physicians and the people to be aware and vigilant
  5. Not to ignore dengue or chikungunya-like symptoms with red eyes
  6. Travellers to Singapore protect themselves from mosquito bites
  7. Pregnant woman: Can pass the Zika virus to her foetus and an infection during pregnancy can cause serious birth defects
  8. Everything you wnat to about Zika here

Zika vaccine trial on monkeys shows promise

  1. Tests were performed on rhesus monkeys
  2. Zika virus strains from both Brazil and Puerto Rico were used for developing the vaccines
  3. None of the vaccinated monkeys developed infection when later challenged with Zika virus

Colombia declares its Zika epidemic over

  1. Background: Zika, which was discovered in Uganda in 1947, took the world by surprise when it emerged in the Americas last year with devastating effects
  2. Zika is mainly transmitted by the Aedes aegypti mosquito, but it has also been shown to spread through sexual contact
  3. Colombia has been the second hardest-hit country by the disease after Brazil
  4. But it is also the first country in the Americas to declare the end of the epidemic

Zika vaccine – hurdles and way forward

  1. Candidate Zika vaccine has to be tested on pregnant women
  2. Hence, it has to be found to be very safe in men and non-pregnant women
  3. Hence, WHO has stated in a report that developing a vaccine that uses inactivated viruses will be a priority
  4. Why? Inactivated virus in vaccine cannot multiply and hence considered safe for use in pregnant women

Human trial of Zika vaccine soon

  1. News: Phase 1 clinical trial of vaccine for the Zika virus to start soon
  2. Might take a couple of years to know whether the vaccine could actually work against Zika
  3. Current vaccine developed by US based Inovio and South Korean GeneOne Life Science
  4. Already tested on animals and found to have robust responses

Olympics should move due to Zika concerns, say medical experts

  1. Context: An open letter signed by 150 international doctors, scientists and researchers called for the upcoming Olympic Games in Rio de Janeiro to be moved or postponed
  2. Reason: To press on with the Games in Rio, the second most affected city in Brazil by the Zika crisis, would be irresponsible and unethical
  3. Concern: Global health- the Brazilian strain of Zika virus harms health in ways that science has not observed before

Zika virus kills cells that form key brain tissue: report

  1. News: Researchers in the U.S. have found that virus severely damages a type of neural stem cell that gives rise to the brain’s cerebral cortex
  2. Study: How the virus entering nervous system of foetus?
  3. Report findings: Zika virus infects neuronal cells in dish that are counterparts to those that form the cortex during human brain development
  4. Context: Findings may correlate with disrupted brain development, but direct evidence for a link between Zika virus and microcephaly is more likely to come from clinical studies
  5. Several questions remain: For instance, why are the symptoms in adults so mild? How is the virus entering the nervous system of the developing foetus?

What’s special about Cuba’s health care?

  1. According to WHO: Cuba’s health care system is an example for all countries of the world
  2. Context: Cuban health system is recognized worldwide for its excellence and its efficiency
  3. Significance: Despite extremely limited resources and the dramatic impact caused by the economic sanctions imposed by the US for more than half a century
  4. Cuba has managed to guarantee access to care for all segments of the population and obtain results similar to those of the most developed nations
  5. Relevance: Cuba is the only country that has a health care system closely linked to research and development
  6. How’s the system? Cuba’s health care system is based on preventive medicine and the results achieved are outstanding

Cuba sending 9,000 soldiers to fight Zika virus

  1. Context: Dispatching soldiers to help keep the Zika virus out of Cuba, calling on the entire country to help kill the mosquito that carries the disease
  2. Cuba’s fight: To prevent the arrival of the virus had been hampered by “the inadequate technical quality” of efforts against the mosquito
  3. Insufficient work to clean up areas where the mosquito propagates and poor weather conditions
  4. Relevance: Cuba has yet to report a case of Zika, which is suspected of causing birth defects in Brazil
  5. Efforts: Door to door fumigation of homes and offices by young army recruits and civilian workers who are supposed to maintain a careful record of places they’ve fumigated

WHO issues $56 million plan to combat Zika virus

  1. Context: help includes the fast-tracking of vaccines, diagnostics and research studies into how it spreads
  2. Funds for: $25 million for WHO and used to control the mosquito-borne virus Zika
  3. Way forward: funds to come from member states and in meantime it has tapped a new emergency contingency fund for $2 million to finance its initial operations

WHO: Genetically modified mosquitoes to combat Zika

  1. Context: New and potentially controversial techniques including releasing GM or irradiated mosquitos could be deployed to hamper the spread of Zika virus
  2. Background: Zika is a disease transmitted by the Aedes aegypti mosquito
  3. More than 13 countries in the Americas have reported sporadic infections
  4. WHO’s advice: To boost the use of both old and new approaches to mosquito control as most immediate line of defence
  5. WHO Advisory Group recommended: field trials and risk assessment to evaluate the impact of this new tool on disease transmission
  6. Relevance: Infection in pregnant women linked repeatedly with a condition in babies called microcephaly and an illness in adults called Guillain-Barré syndrome
  7. Trial results: shown that such releases could reduce an insect population by up to 90%

Plan to eliminate malaria by 2030

  1. Context:  The Lancet estimates that India reports at least 50,000 malaria-related deaths annually
  2. What’s in the news? – The Union Health Ministry announced a plan to eliminate malaria from the country by 2030
  3. The policy intervention will have deliverables and time-bound targets
  4. How? – India will be divided into 3 categories as per malaria prevalence — low, moderate and endemic States
  5. The Ministry will depend on civil society organisations to improve surveillance
  6. States with relatively good capacity and health infrastructure may usher malaria elimination sooner

Is climate change helping Zika spread?

  1. Context: Whenever the planet has faced a major climate change event, species have moved around and their pathogens have come into contact with species with no resistance.
  2. What expert says? The increased global movement of people is probably as great an influence as climate change for the spread of infectious diseases
  3. WHO’s context: Changes in climate mean a redrawn landscape for vector and water-borne diseases
  4. How Transmission? The warmer and wetter conditions facilitate the transmission of mosquito-borne diseases
  5. So, it’s plausible that climate conditions have added the spread of Zika

Learn about Genetically Engineered Mosquitoes?

  1. These mosquitoes contain genes which when passed on to its progeny render them unable to mature
  2. Unless they have access to tetracycline, a compound that is not naturally available in the environment
  3. The idea is that once enough of laboratory-bred mosquitoes mate with the disease-carrying females in an open environment, would reduce the region’s mosquito population
  4. The technology is already being tested in Malaysia and Brazil, which has seen the highest number of Zika cases
  5. The international evidence so far shows the strain can reduce the number of mosquitoes in a place by 90% in 3 or 6 months

With Zika, Indian firm scales up trials for ‘GM mosquitoes’

Such tests would progress quickly as the life span of the Aedes aegypti mosquito was 15 days.

  1. Gangabishan Bhikulal Investment and Trading Ltd. (GBIT), a sister company of the Maharashtra Hybrid Company (Mahyco)
  2. It is planning to scale up trials to find out whether genetically engineered mosquitoes can be a useful tool to check the growth of the insect
  3. It should be noted here that GBIT was the company that first brought Bt cotton to India
  4. Now, GBIT has been breeding male mosquitoes
  5. The company is expected to ask the take the government’s permission to start larger trials later this year

Sexually transmitted Zika case confirmed in Texas

World Health Organization declares global emergency.

  1. A person in Texas has been infected with the Zika virus — the first case of the virus being transmitted in the U.S..
  2. During the current outbreak of Zika which has been linked to birth defects in the Americas.
  3. The Zika virus is usually spread through mosquito bites, but investigators have been exploring the possibility of the virus spreading through sexual contact.
  4. That gives the plausibility of spread, but the science is clear to date that Zika virus is primarily transmitted to people through the bite of an infected mosquito.

Health Ministry issue guidelines on Zika Virus for India

Integrated Disease Surveillance Programme (IDSP) through its community and hospital based data gathering mechanism would track clustering of acute febrile illness and seek primary case.

  1. The Health Ministry issued health advisory, appointing National Centre for Disease Control (NCDC), as the nodal agency for investigation of outbreak- should the situation arise.
  2. This comes in the backdrop of the WHO designating the Zika virus and its suspected complications in newborns as a public health emergency of international concern.
  3. WHO has reported 22 countries and territories in Americas from where local transmission of Zika virus has been reported.
  4. Microcephaly in the newborn and other neurological syndromes (Guillain Barre Syndrome) have been found temporally associated with Zika virus infection.
  5. Rapid Response Teams (RRTs) shall be activated at Central and State surveillance units.

WHO declares Zika a global emergency

WHO estimates there could be up to 4 million cases of Zika in the Americas in the next year.

  1. The WHO has announced that the explosive spread of the Zika virus in the Americas is an “extraordinary event” that merits being declared an international emergency.
  2. The agency convened an emergency meeting of independent experts.
  3. To assess the outbreak after noting a suspicious link between Zika’s arrival in Brazil last year and a surge in the number of babies born with abnormally small heads.
  4. The last such public health emergency was declared for the devastating 2014 Ebola outbreak in West Africa, which killed more than 11,000 people.
  5. Such emergency declarations are meant as an international SOS signal.

Centre forms group to monitor spread of Zika virus

  1. Centre has constituted a special, technical group to monitor the spread of Zika in other countries.
  2. It is focusing on especially strengthening the surveillance system.
  3. There should be an increased focus on prevention to control the spread of the Aedes mosquito, which transmits Zika virus.
  4. There have been no reports of outbreaks of Zika in India though there is concern that given the ubiquity of air travel, carriers of the virus may arrive in India.

Zika could infect 4 mn people: WHO

As of now, cases have been reported in 23 countries and territories in the Americas region.

  1. The WHO expects the Zika virus, which is spreading through the Americas, to affect between 3 million and 4 million people, a disease.
  2. The WHO’s director-general said the spread of the mosquito-borne disease had gone from a mild threat to one of alarming proportions.
  3. There is no vaccine or treatment for Zika, which is a close cousin of dengue and chikungunya and causes mild fever, rash and red eyes.
  4. An estimated 80 per cent of people infected have no symptoms, making it difficult for pregnant women to know whether they have been infected.
  5. Zika was linked to a foetal deformation known as microcephaly, in which infants are born with abnormally small heads.

Let’s know about the Zika virus?

  1. The virus was first identified outside of Africa on Easter Island in 2014.
  2. It attacks the nervous system and can lead to potentially fatal paralysis.
  3. The virus is carried by the Aedes aegypti mosquito.
  4. There is no vaccine, and scientists have warned that developing one could take at least five years.
  5. With the sting of a mosquito bite and a fever, many pregnant women may not know that they caught the Zika virus — until it strikes their unborn child.
  6. The U.S. Centers for Disease Control and Prevention has extended the list of territories on its no-go list for pregnant women.

Birth defects spark panic in Latin America

  1. The United States has expanded a travel warning for pregnant women.
  2. In the last few days, the country has seen over thousands of birth defects.
  3. The defects are blamed on the spread of mosquito-borne Zika virus.
  4. Babies across the region, and at least one in the United States, have been born with abnormally smaller heads — a condition doctors call microcephaly, which can cause brain damage.
  5. The scare has struck hardest in Brazil, which hosts the summer Olympic Games in August.


:( We are working on most probable questions. Do check back this section.







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