Four new cases of Zika virus have been reported in Kerala. After this addition, the number of people infected with this virus in the state has increased to 42. The new cases have been found in Kottayam. Earlier, the cases were found in Thiruvananthapuram. Zika virus can cause microcephaly in babies born to infected women while they were pregnant. Zika virus is a disease spread by the bite of mosquitoes of Aedes aegypti and Aedes albopictus species. These mosquitoes also spread dengue and chikungunya viruses. Aedes mosquitoes usually bite during the day. Once a person is bitten, the virus can be found in some people for a long time in their blood.