Genetic characterization of small ruminant morbillivirus from recently emerging wave of outbreaks in Pakistan

Peste des petits ruminants (PPR) is an endemic and highly infectious disease of several tropical countries, including Pakistan. Despite exhaustive vaccination, outbreaks are on the rise annually across different parts of the country. Clinical outcomes are largely employed to diagnose disease, while comprehensive genomic features of prevailing field strains of SRMV largely remain elusive. Here, we present comparative sequence-based phylogenomics of field strains from three districts representing different agro-livestock production systems during an emerging wave of outbreaks in 2015, together with the first complete genome sequencing of a strain from Pakistan. The analysis revealed clustering of study strain (SRMV/Lahore/UVAS/Pak/2015) to lineage IV, close to isolates characterized previously from India and China. Investigations of inter- and intralineage genetic distances showed a higher genetic distance between SRMV/Lahore/UVAS/Pak/2015 to lineage III viruses than lineages I and II. The characterized Pakistani strain also showed a high percentage of genetic distance from isolates originated from Nigerian and other African small ruminants. Based on these observations, an integrated cross-protection investigation is warranted in the future, not only to define the protective efficacy of currently applied vaccines, but also to continuously elucidate the genomic and evolutionary nature of circulating viruses in the country to achieve disease eradication by 2030.