Zika virus strains linked to fetal microcephaly were not found in Rajasthan, the Union Health Ministry said on November 3.

Microcephaly is a birth defect in which babies are born with extremely small heads. "Advanced molecular studies of zika virus strains, carried out through Next Generation Sequencing suggest that the known mutations linked to fetal microcephaly and high transmissibility of zika virus in Aedes mosquitoes are not present in the current zika virus strain that has affected Rajasthan," a statement by the Ministry said.

It said the Indian Council of Medical Research-National Institute of Virology (ICMR-NIV) had sequenced five zika virus strains collected at different time points of the Jaipur outbreak, which has affected 135 persons. However, the government is maintaining high vigil of the possibility of adverse pregnancy outcomes in women exposed to zika virus as the strain may mutate in future or some other unknown host factors may play a role in microcephaly and other birth defects.

The Ministry said the situation is being reviewed on a daily basis. Around 2,000 samples were tested for zika virus, of which 159 positive cases have been confirmed. "Adequate numbers of testing kits have been provided to the Viral Research and Diagnostic Laboratories," the statement said. 

Rajasthan government has been supplied with Information, Education and Communication (IEC) material to create awareness about zika virus disease and its prevention strategies. All pregnant mothers in the area are being monitored through National Health Mission (NHM). Extensive surveillance and vector control measures are being taken up in the area as per protocol by the state government.

Zika virus disease is an emerging disease currently being reported by 86 countries worldwide. Symptoms of zika virus disease are similar to other viral infections such as dengue, and include fever, skin rashes, conjunctivitis, muscle and joint pain, malaise, and headache.

In India, the first outbreak was reported in Ahmedabad in the beginning of 2017 and the second in July 2017 from Krishnagiri district in Tamil Nadu. It is no longer a Public Health Emergency of International Concern vide World Health Organization's notification issued on November 18, 2016.