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 2007and 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.
In November 2016, the World Health Organization lifted its emergency designation from the mosquito-borne virus, but Zika has hardly disappeared
For families of Zika babies, the disastrous effects are only deepening
Many babies also have a long list of varied symptoms, leading experts to rename their condition “congenital Zika syndrome”
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
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
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
The trials use the Release of Insects carrying Dominant Lethal genes (RIDL) technology
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
Vector Control: The technology uses genetically modified male Aedes aegypti mosquitoes that carry a dominant lethal gene
When male GM mosquitoes mate with wild female mosquitoes the lethal gene is passed on to offspring
The lethal gene in the offspring kills the larvae before they reach adulthood
Since male mosquitoes do not bite humans, the release of GM males will not increase the risk of dengue, chikungunya and Zika
This is very important for prelims. Know about the Vector Control Technology.
What is Vector Control Technology?
Vector control is any method to limit or eradicate the mammals, birds, insects or other arthropods (here collectively called “vectors”) which transmit disease pathogens
The most frequent type of vector control is mosquito control using a variety of strategies
Several of the “neglected tropical diseases” are spread by such vectors
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
As many vector control methods are effective against multiple diseases, they can be integrated together to combat multiple diseases at once
The World Health Organization therefore recommends “Integrated Vector Management” as the process for developing and implementing strategies for vector control