Conclusions
Up to 1.5% of pilgrims carried malaria parasites, posing a risk of spreading malaria to surrounding communities that otherwise would have low or no malaria burden. Moving populations pose the risk of local malaria transmission and reintroduction to the areas undergoing elimination. Sentinel point surveillance at the border of states will be helpful for states to share information on malaria and subsequently for the prevention of malaria transmission.
Methods
A cross-sectional study was conducted for screening malaria in walking pilgrims from neighboring states at selected sites and a follow-up study for screening residents in Rajasthan from 2021 to 2023. The study comprises state entry routes, Ramdevra shrine, and pilgrimage route villages situated in western Rajasthan. Epidemiologic and entomologic surveillance was conducted during the "fair" period (August-September) and in pilgrimage route villages in three different seasons of the year to assess malaria in humans and the vector's infectivity.
Results
Of the 5251 individuals tested for malaria, a total of 76 (1.4%) tested positive for malaria, of whom 40.7% were infected with Plasmodium vivax (n = 31), 36.8% with P. falciparum (n = 28), and 22.3% with P. vivax and P. falciparum (n = 17). Anopheles density was highest during the fair season, peaking in August. An. stephensi exhibited a higher human blood index (0.65) than An. culicifacies (0.50). No mosquitoes were found positive for parasites. Conclusions: Up to 1.5% of pilgrims carried malaria parasites, posing a risk of spreading malaria to surrounding communities that otherwise would have low or no malaria burden. Moving populations pose the risk of local malaria transmission and reintroduction to the areas undergoing elimination. Sentinel point surveillance at the border of states will be helpful for states to share information on malaria and subsequently for the prevention of malaria transmission.