Mosquitoes and other blood-sucking flies spread malaria for more than 100 million years

Credit: OSU

The microorganisms responsible for malaria, leishmaniasis and many other diseases date back to at least the time of the dinosaurs, reveals a study on blood-sucking insects and amber-preserving ticks.

In addition to demonstrating the antiquity of vectors and their long-term badociation with parasitic microorganisms, the results are remarkable for several reasons.

First, leeches such as mosquitoes, fleas, sandflies, ticks and biting midges are not commonly found in amber, and even fewer microorganisms are present.

But a study by entomologist George Poinar of Oregon State University showed that amber from five regions of the world contained blood-sucking arthropods with pathogens and parasites preserved and identifiable.

"The vertebrate blood supply has become an effective way to obtain proteins for the growth and reproduction of certain insects and mites," said Poinar, professor emeritus at the College of Science and international expert on the plant and animal life forms preserved in amber. "It is likely that primitive mosquitoes and other arthropod vectors were present in the Jurbadic and even transmitted pathogens at that time. This would have resulted in widely dispersed diseases, many of which were probably life-threatening for vertebrates when they first appeared. "

Poinar 's leaned on blood – sucking insects and ticks trapped in Dominican, Mexican, Baltic, Canadian and Burmese amber, dating back from 15 million to 100 million years ago.

Among the vectors were mosquitoes, sandflies, biting midges, bat flies, black flies, fleas, bugs and ticks. They carry a multitude of microorganisms that today cause diseases such as filariasis, sleeping sickness, river blindness, typhus, Lyme disease and, perhaps more importantly, malaria. .

Malaria remains a relentless public health problem, with several nations reporting an increase in infections in 2018. In Venezuela alone, Poinar notes, more than 650,000 new cases of malaria have been reported this year.

"Many species of malaria parasitize vertebrates today, and we now know that over the last 100 million years, malaria has been carried by mosquitoes, prickly midge, flies." bats and ticks, "said Poinar. "The obtaining of pathogen fossil records carried by biting arthropods establishes a chronological timeline where and where various diseases have emerged and how they could have affected the survival, extinction, and distribution of these pathogens. vertebrate over time. "

Poinar points out, however, that although his research shows what parasites and pathogens have historically transmitted at particular times and places, "these fossils are not old enough to tell us when and how the badociations between vectors, pathogens and vertebrates originated. "

Poinar believes that the microorganisms first infected blood-sucking arthropods and that the microorganisms were then transported to vertebrates only after the equilibrium was reached.

"This subject has been and will continue to be discussed for years to come," he said.

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