BENGALURU: IF malaria affects millions of people every year then how does it affect birds - from where does it spread to bats, different mammals and then finally man?
Recent research studies have shown that malaria infects wild populations of birds and has caused severe decline in their native populations at lower altitudes. This research marks the beginning of unraveling the complex interplay of climate, altitude, deforestation and infectious diseases in wild birds in a biodiversity-rich region of the world that is rapidly undergoing deforestation.
Learning about its evolutionary history, Dr Farah Ishtiaq, wildlife ecologist with the Centre for Ecological Sciences, Indian Institute of Science, has been conducting field and lab-based studies to understand the spread of this infection in birds.
Dr Ishtiaq and her team have been investigating the effect of infectious diseases on the ecology and evolution of birds. They are now conducting more in-depth studies in the Western Himalayan region to unravel the initial findings of patterns of higher prevalence of malarial parasites at low altitudes and in native populations of birds in Asia.
Dr Ishtiaq says, “When we think about malaria, we immediately think of people in tropical areas being bitten by mosquitoes and getting infected with the disease. However, malarial parasites influence bird populations, but we don’t always make that connection.”
“The plains along the Terai region were once infamous for high rates of malaria infection until it was controlled through the use of DDT in 1950s. Species in the plains may have evolved with malaria and other blood parasites, but high-elevation residents may not have been exposed to the parasites during their evolutionary history. So we can hypothesise that the resident high-altitude bird species have low prevalence of the malarial parasite. And the ones in the plains could be reservoirs of the parasites with the altitudinal migrants acting as the bridge for parasites between their wintering and breeding grounds,” she says.