Prehistoric problems: Midges and malaria helped kill off dinosaurs

29 Mar 20164 Shares

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Crocodile eye, via Wikimedia Commons. It’s not a dinosaur eye, but there are notoriously camera-shy.

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Malaria killed around 440,000 people in 2015. But did you know the same disease, spread by biting insects, killed off some dinosaurs, too?

The biting midge. Midges. Midgies. Midgets. Sand flies. These are all colloquialisms for those incredibly annoying, tiny little flies that bite you during the summer months. They are also colloquialisms for what dinosaurs probably thought were incredibly annoying, tiny little flies.

That’s according to a new piece of research that has dated malaria, largely thought to be a relatively modern disease, all the way back to when dinosaurs ruled the earth.

Looking at a 100m-year-old midge, preserved in amber, George Poinar, a researcher in the College of Science at Oregon State University, found something interesting. There were numerous oocysts of the malarial parasite Paleohaemoproteusburmacis, evidence of the oldest-ever ancestral strain of malaria.

Malaria through the ages

It is through these hosts, he suggests, that malaria ultimately got into the planet’s megafauna and, most likely, dinosaurs too. An active investigator into what killed off the dinosaurs, Poiner has long argued that some sort of disease was the primary suspect.

Accepting “catastrophic events” throughout the age of the dinosaurs – volcanic eruptions, meteor strikes etc – Poinar argued that the true die-off took thousands of years. This suggests other issues must also have been at work. “Insects, microbial pathogens and vertebrate diseases were just emerging around that same time, including malaria,” he said.

And it’s the latter that he’s most interested in, arguing that the spread of malaria-shaped vertebrate survive right up to today.

On the left is a 15- to 20-million-year-old mosquito Culex malariager, which was discovered in the Dominican Republic preserved in amber, and is infected with the malarial parasite Plasmodium dominicana. It's the oldest known fossil showing Plasmodium malaria, related to the type that today infects humans. On the right, however, is a biting midge five-times older, which shows numerous oocysts of the malarial parasite Paleohaemoproteusburmacis, evidence of the oldest ancestral strain of malaria ever discovered. Images via George Poinar Jr/Oregon State University

On the left is a 15- to 20-million-year-old mosquito Culex malariager, which was discovered in the Dominican Republic preserved in amber, and is infected with the malarial parasite Plasmodium dominicana. It’s the oldest known fossil showing Plasmodium malaria, related to the type that today infects humans. On the right, however, is a biting midge five-times older, which shows numerous oocysts of the malarial parasite Paleohaemoproteusburmacis, evidence of the oldest ancestral strain of malaria ever discovered. Images via George Poinar Jr/Oregon State University

Malaria is credited with killing off entire species of birds – notably in Hawaii where, when it was introduced in the early 19th century, no native species had built up immunity – and some even blame the fall of certain civilisations on the disease’s spread.

Finding the true host has always proved difficult, with mosquitos often credited with its spread. As it is sexually-transmitted among insects, finding any species older than that, which hosts the disease, is key.

So, Poinar’s 100m-year-old midge is the latest prime suspect.

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Gordon Hunt is a journalist at Siliconrepublic.com

editorial@siliconrepublic.com