Most scientists agree that both an asteroid impact and the toxic fumes from volcanic eruptions have led to the extinction of dinosaurs millions of years ago.
But who would have thought that a disease that affects us today had also plagued these animals?
That's right. Although a previous paper suggested that malaria originated from gorillas, a new study says malaria dates back to at least 100 million years ago and could have played a role in the slow decline of the dinosaur population.
Malaria is a mosquito-borne disease that killed half a million people and infected 214 million individuals worldwide in 2015, according to the World Health Organization (WHO).
The most common and deadly strain of this disease is from Plasmodium falciparum, a parasite spread through bites of the Anopheles mosquito.
"Scientists have argued and disagreed for a long time about how malaria evolved and how old it is," said George Poinar Jr. from Oregon State University.
The general consensus is around 15,000 to 8 million years ago. But the new study, which is led by Poinar, offers fossil evidence that a form of malaria related to the current strain that infects humans, animals and birds had already existed in mosquitoes at least 20 million years ago.
The research also presented the presence of an ancient strain of malaria in a 100-million-year-old biting midge.
Discovering The Oldest Malaria Strain
Poinar, who is a writer and an entomologist known for extracting DNA from insects fossilized in amber, was the first to find a 15 to 20 million-year-old mosquito called the Culex malariager.
Naturally, this prehistoric mosquito was preserved in amber and was discovered in the Dominican Republic, which is part of what people used to call the "New World."
The Culex malariager was apparently infected with Plasmodium dominicana, which is strongly related to the Plasmodium strain that affects modern humans and other species.
Poinar said the fossil demonstrated that this genus was established in the New World at least 15 million years ago. He also pointed to his discovery of a biting midge named Protoculicoides, which is about 100 million years old and was preserved in an amber.
This ancient insect contained the parasite Paleohaemoproteus burmacis. It is the oldest strain of malaria ever discovered.
Carriers Of The Deadly Disease
A recent study reported by Tech Times revealed that malaria may have been originally carried by modern bird hosts and then eventually spread to mammals such as bats.
Could dinosaurs have been carriers of malaria, too? Could it have contributed to their death and extinction about 65 million years ago?
Poinar believes it is possible.
Catastrophic events such as asteroid impacts and lava flows from eruptions happened at that period, he said, but it's also clear that dinosaurs declined and slowly became extinct over the next thousand years.
Poinar said this indicates that other factors must have been at work. He said microbial pathogens, disease that attacked vertebrates, and insects were just emerging around the same time dinosaurs were dying. One of the diseases was malaria.
Examining the origins of malaria are relevant in gaining a better understanding of the modern-day strain. It helps scientists comprehend how the disease evolved over millions of years. It could even provide insight into ways to stop transmission through the modern vector.
The findings of this study are published in the journal American Entomologist.
Photos : Oregon State University | Flickr