Contrary to popular notion, a new study suggests that the origins of malaria date back to the dinosaur age, with the disease being a possible contributor to the reptiles’ extinction.
Study author George Poinar Jr., of the College of Science at Oregon State University, publishes his findings in the journal American Entomologist.
Malaria is a potentially fatal disease caused by the Plasmodium parasite, which is spread through bites of infected Anopheles mosquitoes.
According to the World Health Organization (WHO), there were approximately 214 million cases of malaria across the globe last year and around 438,000 deaths from the disease.
Poinar notes that researchers have long debated the origins of malaria, with the general consensus being that the disease is around 15,000-8 million years old.
However, in this latest study, Poinar presents fossil evidence that a form of malaria related to the modern-day strain that currently infects humans – as well as birds and animals – existed in mosquitoes more than 20 million years ago.
What is more, the research reveals the presence of an ancestral strain of the malaria parasite in a 100-million-year-old biting midge.
Poinar was the first researcher to discover a 15-20-million-year-old mosquito called the Culex malariager. Preserved in amber, the mosquito was found in the Dominican Republic, once referred to as the “New World.”
Poinar reveals that the mosquito was infected with the malarial parasite Plasmodium dominicana, related to the Plasmodium strain responsible for human infections today.
“Aside from being the first fossil record of Plasmodium malaria, the fossil demonstrated that this genus was established in the New World at least 15 million years ago, thus putting the history of malaria in the New World in a different perspective,” notes Poinar.
Poinar also points to an analysis of an amber-preserved biting midge known as Protoculicoides, which is around 100 million years old.
The ancient midge was found to contain the malarial parasite Paleohaemoproteus burmacis, making it the oldest ancestral strain of malaria ever discovered.
Commenting on the findings, Poinar says:
“Scientists have argued and disagreed for a long time about how malaria evolved and how old it is. I think the fossil evidence shows that modern malaria vectored by mosquitoes is at least 20 million years old, and earlier forms of the disease, carried by biting midges, are at least 100 million years old and probably much older.”
Based on the evidence to date, Poinar suggests that malaria may have begun more than 100 million years ago, when dinosaurs were roaming the earth.
Does this mean the reptiles could have been carriers of the disease? And could malaria have contributed to their extinction around 65 million years ago? It is certainly possible, according to Poinar.
“There were catastrophic events known to have happened around that time, such as asteroid impacts and lava flows,” he says.
“But it’s still clear that dinosaurs declined and slowly became extinct over thousands of years, which suggests other issues must also have been at work. Insects, microbial pathogens and vertebrate diseases were just emerging around that same time, including malaria.”
Explaining how the latest findings are relevant to modern-day malaria, Poina notes that gaining a better understanding of how the disease has evolved over millions of years may provide insight into ways to halt transmission through today’s vector – the Anopheles mosquito.
Last November, Medical News Today reported on a study in which researchers shed light on how the malaria parasite invades the liver, where it replicates before entering the bloodstream.