New Delhi: The death of a 74-year-old man in Karnataka’s Shivamogga district, suspected to have been caused by the Zika virus, and several samples testing positive for the pathogen over the last few days at the Indian Council of Medical Research-National Institute of Virology (ICMR-NIV), Pune, has set off alarm bells.
During the ongoing outbreak of Zika virus — a pathogen whose vector is the Aedes mosquito (also the vector for chikungunya and dengue) — cases have been reported from at least three districts in Maharashtra: Pune, Kolhapur and Ahmednagar. Other states from which cases have been reported are Karnataka and Kerala.
According to a report by the Times of India (TOI), the situation is grim in Pune, where ICMR-NIV is overwhelmed with the number of samples. Till the morning of 8 July, the number of confirmed cases was nine, which included three pregnant women.
Centre warns states to remain vigilant
The ongoing outbreak of the virus, first reported in India in Gujarat in 2016, prompted the Ministry of Health and Family Welfare to issue an advisory to states, asking them to alert clinicians for close monitoring of the cases.
The Centre also urged states to instruct health facilities in the affected areas and healthcare workers looking after cases in affected areas to screen pregnant women for Zika virus infection, and monitor the growth of the foetus in expecting mothers who have tested positive for Zika virus.
States were also instructed to immediately report any detected case to Integrated Disease Surveillance Programme (IDSP) and National Center for Vector Borne Diseases Control (NCVBDC).
The ministry also asked the states to strengthen entomological (relating to the study of insects and their relationship with humans, environment, and other organisms) surveillance and intensify vector control activities in residential areas, workplaces, schools, construction sites, institutions and health facilities.
“A Zika virus outbreak is always of concern, especially in densely populated cities with mosquitos, an ideal setting for its transmission. The effectively solvable part is vector control, as it is for other vector borne diseases,” Dr Anurag Agarwal, dean, biosciences and health sesearch, Trivedi School of BioSciences, Ashoka University, told ThePrint. Agarwal is a former director of the Council of Scientific and Industrial Research–Institute of Genomics and Integrative Biology (CSIR-IGIB).
Zika virus transmission, symptoms, risk
Infected mosquitoes of the Aedes genus, mainly Aedes aegypti, act as vectors of transmission for the Zika virus, mostly in tropical and subtropical regions. This species usually bites during the day, and can also transmit dengue, chikungunya and urban yellow fever.
This virus can also be transmitted from mother to foetus during pregnancy, as well as through sexual contact, transfusion of blood and blood products, and organ transplantation.
Most people with Zika virus infection do not develop symptoms and those who do, typically show symptoms three to 14 days after infection. Symptoms include rash, fever, conjunctivitis, muscle and joint pain, malaise and headache, according to the World Health Organization (WHO). These mostly last for two to seven days, and are usually mild.
“When (Zika) infection occurs in an endemic setting of dengue, chikungunya and other viral infections, there is a significant overlap in symptoms, and it is likely for infections to be missed, unless they are tested,” biologist and medical researcher Dr Vinod Scaria, told ThePrint.
Complications when Zika virus infection happens during pregnancy
The major risk from Zika is during pregnancy, especially in the third trimester, Scaria said.
This is because Zika virus infection during pregnancy can cause infants to be born with microcephaly (the baby’s head being much smaller than expected) or other congenital malformations, preterm birth, stillbirth, and miscarriage.
The WHO suggests the prevalence of microcephaly in 5 to 15 percent of babies whose mothers are infected with Zika virus during pregnancy.
Infection during pregnancy can also lead to Guillain-Barré syndrome, an autoimmune disorder that results in damage to peripheral nerves, neuropathy (a nerve problem resulting in numbness, tingling, swelling, pain, and weakness in muscles), and myelitis (inflammation of the spinal cord), particularly in adults and older children.
The worrying factor is that no specific treatment is available for Zika virus infection or disease, but only medications for managing the disease can be administered. Symptoms such as rash, fever or joint pain can be managed with plenty of rest, fluids, and antipyretics or analgesics.
If symptoms worsen, patients should seek medical care and advice.
Pregnant women living in areas with Zika transmission or those who develop symptoms of infection, on the other hand, are advised to undergo laboratory testing, and seek counselling and other clinical care.
Lack of testing, surveillance a challenge for India
According to Dr Manoj Murhekar, director of the ICMR-National Institute of Epidemiology, most Zika infections during the current outbreak in the country are from select localities, suggesting a localised outbreak.
“However, continued surveillance will be necessary to monitor how the outbreak evolves,” Dr Murhekar told ThePrint.
Experts also suggested that tests should be widely available and more accessible so that private labs can test beyond the limited capacities of national labs, and a greater number of people can be benefited.
Crucial tools to fight the outbreak include increased surveillance of infections in pregnant women, and obtaining genomes (viral sequences) from outbreaks and scaling them up at a faster pace.
Scaria emphasised that the rapid development of Zika tests would require rapid availability of genomes from the outbreaks in the public domain.
He said that for patients and clinicians to understand the risk and base their decisions on evidence, there is a need for wider testing and screening.
“However, we do not have any diagnostic tests approved by the Central Drugs Standard Control Organisation (CDSCO). This limits the wide use of tests,” he said.
According to the health ministry, as of now, Zika testing facilities are available at NIV, Pune, National Centre for Disease Control (NCDC), Delhi, and a few selected virus research and diagnostic laboratories under the ICMR.
“The delays in release of genomic data are unexplainable. Additionally, genomic surveillance and sequencing similar to what was done during the COVID-19 pandemic could provide very useful insights into transmission patterns and ways to understand the outbreak and suggest means to contain the spread,” Dr Scaria said.
Dr Agarwal, too, said that while designing vaccines and drugs takes time, genomic surveillance will help in understanding the spread, and may provide crucial information for future therapeutics.
ThePrint reached Union Health Secretary Apurva Chandra via telephone and text messages to understand what steps were being taken to intensify Zika surveillance and ensure wider availability of its testing. This report will be updated if and when a reply is received.
(Edited by Radifah Kabir)
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