Information hidden in the entrails of Egyptian mummies and in ancient human burial sites could help reduce allergies in children and adults today.
Human remains have tales to tell if you know where to look and Dr Piers Mitchell knew where and what to look for. He wanted to understand when parasites such as worms and fluke first started to infect humans and see what impact parasites might have had on human evolution.
The clues themselves were fossilised egg cases and worms, proof of infection and also of the kinds of parasites our ancient relatives carried. Details of the research were published last week in the International Journal of Paleopathology, and he discussed them today on the closing day of the British Science Festival in Newcastle.
The evidence could be found in mummified bodies from Egypt, South America and the Sudan and in any human burial ground. Egg casings and worms could also be found in "coprolites", fossilised human faeces, he said.
He collated information available from around the world, trying to get a picture of what parasites our ancestors carried but also to study the migratory paths they followed.
He identified what he called 16 "heirloom" parasites. These were the infectious agents that existed as early humans evolved, parasites that in turn would later be carried away by them as they moved to colonise places away from Africa.
The list is very familiar given these parasites are with us today such as roundworm, tapeworm, liver fluke and toxoplasmosis to name a few. Only 10 left however, as evidenced by their disappearance from human remains probably because the six parasites could not survive away from Africa, Dr Mitchell said.
But migrating humans picked up 12 new “souvenir” parasites “in the way you might acquire a souvenir on holidays”, he said. Examples included a number of flukes, chagas and others, with the evidence again found in the burial remains.
The parasite evidence tells us about the health of past populations, whether they were hunter gatherers in Africa, Chinese emperors or Incas in South America, Dr Mitchell said.
This data looks towards the past but there is an important future dimension to it. The data could help research into allergies experienced by modern day humans.
The human immune system fights parasitic infections such as worms, fluke and malaria using a specialised immune protein called IgE. But this same protein goes off-kilter when a person suffers from allergies, driving all the symptoms from blocked sinuses to asthma.
Allergies are on the rise in western society, with children in particular suffering, Dr Mitchell said. Researchers believe this might be because we no longer carry a burden of parasites in our overly clean environment, effectively leaving the IgE with nothing to do but drive allergies.
The response is experiments where a person is intentionally infected with worms to see if this lessens allergic symptoms.
