India experienced a Zika Outbreak thrice in the last two years. Vikram Thakur discusses the virus and what is being done to contain it.
In the last three years, India has faced various viral epidemics in diverse geographical corner. For example, in 2016, Himachal Pradesh reported approximately 15000 cases of Hepatitis-E after an outbreak of jaundice. In May-July of 2018, a Nipah virus outbreak rocked South India where 19 confirmed cases with 17 deaths were reported. Virologist Prof.G Arun Kumar and his team identified the virus which assure that the spread of Nipah was confined to Kerala. This was the third Nipah outbreak known to occur in India. In the past, India has experienced two Nipah outbreaks in Eastern India (West Bengal: 2001,2007). The major hurdle was the non-availability of vaccine for treating the viral infections. Even the lions in the Gir sanctuary were not spared by the viruses: Canine Distemper Virus (CDV) has killed 23 Asiatic lions since September, in Gujarat’s Gir sanctuary with at least 21 more lions infected.
Now, we are facing an outbreak of Zika virus in Western India (Rajasthan: Jaipur), where so far, 130 positive cases (including 22 pregnant women) have been reported. The focal point was identified as Jaipur’s Shastrinagar with the first human case reported on 23 September 2018 and virus traces in Aedes aegypti mosquitoes on September 26, 2018.
Responses by the Indian Government
Union Health Minister, Shri. J P Nadda assured the nation, “That everything is under control” and all the possible effective measure had been implemented from the Central Government. A seven member high-level team was constituted in Jaipur to assist state government and a control room was set up at the National Centre for Disease Control (NCDC) to undertake control and containment operations. More than 10,000 families and 168 pregnant women (22 positives for Zika virus) were screened for Zika virus. Control measures like fogging, spraying and treating containers with chemicals was done and 29000 mosquito breeding grounds have been destroyed as a control measure. Mosquito samples were also examined and screened for Zika virus. Bihar has also issued advisory for preventive measures and the family of Zika positive residents of Bihar were monitored to prevent further incidences. Sufficient medicines were stockpiled, viral research and diagnostic laboratories (VRDL) were provided with diagnostic kits. The state government is also ramping up efforts to raise awareness about Zika to restrict the spread of infection.
Cause and Effect
Zika virus was first identified in 1947 in Uganda and remained unknown until a large outbreak in 2007 in Micronesia was reported. It is primarily known to transmit by Aedes aegypti mosquitoes (day biting) in addition to the recently identified sexual route of transmission. Zika virus is mostly known to cause mild illness with symptoms like fever, rash, muscle and joint pain and headache which last for 2-7 days. The severe complications associated with Zika virus infection in pregnant women is brain abnormality in the babies in the womb, this defect is known as microcephaly (small heads). Also, a rare neurological disorder i.e. Guillain-Barre Syndrome (GBS), causing paralysis in adults and children, is attributed to Zika infection. Zika virus has no treatment/cure or vaccine. Patients are advised to take rest and drink fluids. If fever persists, common medicine/antiviral can be the option as the symptomatic treatment.
Drug repurposing is one of the ways to combat a viral infection which has no antiviral drug or vaccine. So far, three potential drugs have been proposed by screening 6000 approved drugs and clinical trials candidates. Niclosamide (originally for tapeworm treatment) inhibits Zika replication whereas PHA-690509 interferes with gene expression. The third drug Emricasan inhibits programmed cell death and may protect brain cells of developing fetuses against viral damage. Based on trials in mice, scientists suggest that Sofosbuvir (antiviral for HCV) can be used off-label for Zika, as it targets viral DNA and blocks the Zika transmission from the mother to the baby. Zika virus accompanied with microcephaly and uncommon Guillain-Barre syndrome (GBS), has also raised the quest for vaccine research. Pharmaceutical giants GlaxoSmithKline (GSK), Sanofi and Inovio pharmaceuticals are working hard for the effective DNA-based vaccine for Zika.
Vikram Thakur is a PhD scholar at the Department of Virology, PGIMER, Chandigarh