Viruses mutate, emerge, re-emerge
IN 2015, World Health Organization (WHO) published a list of top emerging pathogens likely to cause severe outbreaks in the near future. Other than chikungunya, the list of pathogens includes Zika, Crimean-Congo haemoerrhagic fever, filovirus diseases such as Ebola, coronaviruses like MERS Co-V and SARS, Lassa Fever, Nipah and Rift Valley Fever.
In recent years, there is evidence that mutations have become more common. In the case of Ebola, the virus that caused the 2014 outbreak was different from those that caused outbreaks earlier. It had accumulated more than 395 mutations between 2014 and 2016, when the researchers collected the last samples. In 2003, researchers identified eight mutations in dengue virus type 4. Chikungunya, which was largely confined to developing countries in Africa and Asia before 2004, reached developed nations, like France, due to a single amino acid change in the envelope glycoprotein.