Travellers coming in from Dubai and the United Kingdom were the main sources of coronavirus importations into India, an analytical study by the Indian Institute of Technology, Mandi, reported PTI.

The study, published in the Journal of Travel Medicine, said that the infection spread to Indian states primarily due to international travels.

The study also found that those infected from Tamil Nadu, Andhra Pradesh and Delhi did not play a significant role in spreading the disease. However, people infected in Rajasthan, Gujarat, Maharashtra, Jammu and Kashmir, Karnataka, Kerala played a major role in local transmission and spread of inter-state cases.

The team of researchers used the travel history of those infected between January and April as the primary data source and a social network was created depicting the spread in the early phase of the pandemic. “The research found that the maximum numbers of connections were established from Dubai (144) and the UK (64),” IIT-Mandi Assistant Professor Sarita Azad told PTI. “We tracked the spread of Covid-19 and its diffusion from the global to national level and identified a few super spreaders who played a central role in the transmission of the disease in India.”

In phase one, the spread of the infection was traced using the travel history of patients and it was found that most of them were local transmissions. Azad also explained that statistical metrics analysed from the data showed that travellers from Dubai and the United Kingdom played a crucial role in spreading the disease.

“Dubai’s eigenvector centrality was the highest that made it the most influential node,” she said. In graph theory, the eigenvector centrality measures the effect of a node in a network. The professor said that different clusters were seen forming across Indian states, based on the modularity class, adding that this demonstrated the formation of a multi-layered social network structure.

Azad also noted that a marked increase in overall cases was reported from states such as Tamil Nadu, Delhi and Andhra Pradesh during the first phase of the nationwide lockdown. “The modularity class of states such as Tamil Nadu, Delhi, and Andhra Pradesh was low,” she said. “Hence, it is likely that infected cases from these states played less of a role in spreading the disease outside their communities.”

India’s coronavirus case count inched closer to the 60-lakh mark after 88,600 new infections were reported on Sunday. The country now has total 59,92,532 cases. The toll rose by 1,124 to 94,503. The mortality rate stood at 1.61%, while the recovery rate is at 82.1%.