The parasite that destroyed Britain’s greenfinch population, bringing the numbers of the much-loved green-yellow garden birds from around 4.3 million breeding pairs in 2005 to fewer than 1.5 million in 2016, has been discovered in the common Indian myna. The parasite, Trichomonas gallinae, causes Avian trichomonosis, a disease common among the columbid class of birds, viz., pigeons and doves, worldwide. It causes sores in the throats of these birds, and of birds that prey on them, making it difficult for them to feed, and resulting eventually in death.
The authors of the research screened 167 mynas captured from eight locations in Pakistan’s Faisalabad district, and found 20% of the birds to be infected. The birds that tested positive to the parasite were spread across all eight locations. “The parasite is an ancient one, it has been said that it used to even infect dinosaurs,” Dr Kevin Tyler from the University of East Anglia, and a senior author of the study, told The Indian Express. “In the UK in 2005, one strain was able to infect the UK greenfinch which is a pretty little bird found widely there at the time. During the last 12 years since that discovery, the disease, finch trichomonosis, has been spread amongst the greenfinches and other UK finches…,” he said.
A press release issued by the University of East Anglia quoted Dr Tyler as saying “mynas are able to roost almost anywhere in warm climates, which… could also mean they are likely to spread the disease further”. Dr Tyler told The Indian Express that even though the research had been confined to Faisalabad in Pakistan, it was “very likely” that the infection would be found in India.
The birds studied by the researchers in Pakistan did not, however, show symptoms, and were found not to be fatally infected. This is probably because of the particular strain of the parasite they carried.
“In this study, C4, a genotype that is less associated with such virulence characteristics than A1, is prevalent in live, asymptomatic birds, suggesting that myna has the potential to be a vector for this parasite,” says the study. The UK finches were attacked by the A1 strain. Tyler said it did not appear that the parasite, which is similar to another (Trichomonas vaginalis) that causes the common STD trichomoniasis in humans, has caused any human infections so far.