Zika virus: the need to improve surveillance and vector control
- The Zika virus is making the news once again. At least 15 cases, including eight pregnant women, of Zika have been discovered so far in Pune, Maharashtra.
Keypoints
- The Pune Municipal Corporation has said it has stepped up surveillance; the Karnataka Health Department has released guidelines on the virus for the public, and both States have urged members of the public to ensure there are no mosquito-breeding sites at their homes.
- The Indian Council of Medical Research (ICMR) has asked States not only to increase testing for Zika but also to test patients with chikungunya and dengue-like symptoms who test negative for these infections for Zika, as per a news report.
- As the monsoon continues over large parts of the country, creating ideal breeding grounds for mosquitoes, and with cases of dengue spiking as well, State administrations and members of the public need to step up mosquito-control measures to prevent transmission of diseases.
What is Zika virus?
- As per the World Health Organization (WHO), Zika virus is a mosquito-borne virus first identified in Uganda in 1947 in a Rhesus macaque monkey, followed by evidence of infection and disease in humans in other African countries in the 1950s.
- Zika virus occurs through the bite of infected Aedes mosquitoes, mainly Aedes Aegypti, which also transmits dengue and chikungunya.
- Sexual transmission, transmission from mother to fetus and transfusions of blood and blood products are other routes of transmission.
How does it manifest
- Most people infected with the Zika virus do not develop symptoms.
- Among those who do, they typically start 3–14 days after infection and are generally mild, including rash, fever, conjunctivitis, muscle and joint pain, and headache, which usually last for 2–7 days.
How is it diagnosed?
- Zika virus may be suspected based on symptoms or the fact that the person is living in or visiting areas where Zika transmission has occurred.
- A diagnosis can only be given after a laboratory test.
- The Central Drugs Standard Control Organisation (CDSCO), India’s apex agency for diagnostic approvals, confirmed that there was no approved diagnostic test for Zika.
- This limitation, the report said, hinders the country’s ability to diagnose Zika. At present, samples are generally sent to a few select labs, including the National Institute of Virology, for confirmation
What are the ill effects?
- Zika virus infection during pregnancy, the WHO says, can cause infants to be born with microcephaly and other congenital malformations and can also cause preterm births and miscarriage.
- Zika virus infection is also associated with Guillain-Barré syndrome, neuropathy, and myelitis in adults and children. Guillain-Barré syndrome is a rare condition that causes a person’s immune system to attack the peripheral nerves.
Is there a vaccine?
- No vaccine is as yet available for the prevention or treatment of Zika virus infection, the WHO says. The development of a Zika vaccine remains an active area of research.
- A few studies have shown promising results. In India for instance, several companies are attempting to make a vaccine. In a study published in 2017, Bharat Biotech’s “killed Zika virus vaccine” which uses an African strain showed 100% efficacy against mortality and disease in animal studies.
- Indian Immunologicals Limited, a wholly-owned subsidiary of the National Dairy Development Board said earlier this year that it was also working on developing a vaccine.