Locked within lice’s writhing bodies are some of humanity’s deepest mysteries. From the spread of Homo sapiens, to Jewish rebels’ wartime conditions at Masada, the study of these most ancient parasites sheds light on no less than the development of mankind.
But — horrors! — a few weeks ago four of the six children and I found ourselves yet again infested. The kids, turning quantity time into quality time, decided to pick my brain during our twice-daily fine-tooth combing sessions.
“Why did God create lice?” moaned the 8-year-old princess at a particularly nasty tangle. Her 12-year-old sister thoughtfully wondered, “If lice prey on us, who eats them?”
Scratching my head to find answers, I turned to Israel’s preeminent lice expert.
“Why did God create lice?” laughed Prof. Kosta Y. Mumcuoglu, a medical entomologist who works as a senior research scientist in the Hebrew University-Hadassah Medical School’s Department of Parasitology. “They are the same as any other living organism — like an elephant. They exist.”
Lice, he acknowledged during a phone call this week from his native Turkey, do have a bit more of a PR problem than the lofty pachyderm due to their parasitic lifestyle. In this case, they are living off of us.
“It’s very difficult to convince people about the advantages of lice… But if you start studying the louse… you cannot stop marveling about how many wonders there are in every organism,” said Mumcuoglu, who has researched lice for over 35 years.
Lice have accompanied mankind’s many evolutionary forms for 6-7 million years. Today, there are three types that infest humans — head, body, and pubic lice — and each one has its own origin story.
A sprinkling of fun lice facts: By the time you witness your child scratching his head, he’s already been infested for about a month. Each louse bites about five times a day, and a person can host dozens of them. Contrary to popular belief, lice cannot jump or fly.
The study of ancient lice is more than a font of interesting trivia, however. It gives an intimate look at historical conditions and the body of evidence is growing. Prehistoric body lice were discovered on a human skeleton in Brazil from up to 10,000 years ago, as well as head lice from 9,000 years ago in Israel’s Nahal Hemar cave.
Alongside the critters themselves, combs and other treatments to get rid of them were uncovered from as early as circa 1500 BCE. Many of the earliest combs are found in Israel from the Roman period (beginning circa 2100 years ago).
Dr. Orit Shamir, curator of Organic Materials for the Israel Antiquities Authority, explained that when such combs are uncovered during a dig, they are taken, as-is, to the laboratory for microscopic inspection, which is usually performed by Mumcuoglu. In keeping with the practices of archaeologists at excavations, Mumcuoglu does not remove all the evidence of lice from combs, rather leaves some for future scientists to study as well.
According to Shamir, many of the combs discovered in Israel are crafted from the wood of Turkish Boxwood trees (Buxus sempervirens), in addition to native Israeli Acacia. The strength of the Boxwood tree, she said, allowed for fine-tooth combs with densely crowded tines which catch more and smaller lice and eggs. Being an import item, effort and resources were invested in the making and procurement of these mostly two-sided louse combs, which, it can be inferred, illustrates their relative importance in Roman-era life.
Mumcuoglu has examined some 50 ancient combs, ranging from 500 to 2,500 years in age. On about half he found the remains of lice or their eggs, he said. On one 2,000-year-old comb, he said he discovered over 80 eggs; on another from 2,500 years ago, over 10 lice.
“We know that they were using effective tools,” he said. Made of wood, ivory or metal, they would have been much more painful than today’s combs, he added.
The study of these combs, the relative amount of head lice on them, and the quality of any captured hair illustrate more than the hygiene methods of the time. At Masada, said the IAA’s Shamir, discovered first century hair is of an “inferior quality,” which showed the paucity of nutrients in the rebels’ diets.
Shamir contrasted the unkempt Masada hair with first century CE remains of a wealthy Jew found in Jerusalem’s Hinnom Valley. Lice were not found on the individual and the hair “was shiny, freshly washed, and clean,” said Shamir. “Through their hair, we can learn about their diets,” she said.
Body lice also give telling insight into ancient living conditions. During the revolt at Masada, portions of King Herod’s palaces were repurposed for the Jewish rebels fighting the Romans (66–73/4 CE). As the popular telling of the story goes, dramatically, the rebels decided to finish themselves off rather than spend a life in servitude, casting lots to see who would carry out the deadly duty. Their names were found written on pottery sherds, which are now on display in the Masada museum.
Also found in the same storeroom complex occupied by the rebels was a basket that contained fragmentary textiles — and remains of body lice. “Not destroyed by fire, this locus was abandoned at the end of the revolt and was never reoccupied. The louse remains were found in association with a group of textiles that is dated to the time of the revolt,” according to a 2003 article in the Journal of Medical Entomology.
Body lice, found in the textiles, are known to spread diseases. The rebels, living in close quarters in the most difficult of conditions, would have been easy targets for the pests, which scientists label “vectors of bacterial pathogens.” Even as the Romans had Masada under siege, it is likely the rebels were slowly wasting away from disease and pestilence.
The great lice migration
The oldest fossils of lice are reportedly about 10 times larger than today’s minuscule parasites. What we see on contemporary humans are head lice (Pediculus humanus capitis) and body lice (Pediculus humanus humanus), different subspecies of the same organism, as well as pubic lice or crabs, which are from a different genus, Pthirus pubis.
Pubic lice is evolutionary close to gorilla lice, whereas head and body lice are similar to lice found on chimpanzees. Head and body lice are so closely related that they can, if the conditions are ripe, still interbreed and have progeny. According to Mumcuoglu, there are also indications that head lice can morph into body lice.
Through looking at ancient head and body lice’s mitochondrial DNA, scientists have pinpointed different “clades,” or common ancestral groups of organisms, and been able to chart the migration of humans based on the spread of these clades of lice. One surprising result showed that a form of lice that originated in the Middle East and is mostly found in Europe today, was discovered in a South American sample dated to 10,000 years ago. The linkage of the Middle Eastern and South American sample showed that this type of lice wasn’t brought over by the European conquerors, rather arrived much earlier through human, or ancient hominid, migration via Asia.
It appears as well that different lice strains developed on different strains of hominids. The 2016 study, “High Ancient Genetic Diversity of Human Lice, Pediculus humanus, from Israel Reveals New Insights into the Origin of Clade B Lice” shows that lice clades evolved on different lineages of humans. “Their geographic distribution can provide information regarding the evolutionary history of the lice as well as their human hosts.”
In other words, depending on which type of lice is discovered and where, scientists can draw conclusions about early man’s migration patterns.
By the way, apropos my daughter’s question about who preys on lice, it appears that the answer is — we do. Coprolites, or prehistoric fossilized human excrement from North America shows remnants of lice that would have been passed through the individual’s digestive tract.
Mumcuoglu said that humans eating lice is also a contemporary phenomena, observed in tribal groups, for example in Africa. “While taking out the lice, they eat it. It is, after all, a protein” he said. “The apes also do that very nicely — examine and groom each other and eat the lice,” he said.
No school like the old school for treatment
It is important to note that only body, not head, lice appear to spread nasty diseases. And although head lice can be infected — through drinking contaminated blood — they do not appear to spread epidemics.
“Today head lice is a question of emotion, psychology, rather than a physical problem,” said Mumcuoglu. “There is a stigma related to poverty. And while that was perhaps quite the case 100 years ago, today, very very clean individuals still have them,” he said.
Except in rare cases of secondary infection, head lice is not a clinical problem, but rather a psychological one, emphasized Mumcuoglu. “The damage it does to humans is minimal and appears that, after a period, chronically infested people suffer much less from pruritus,” or extreme itching.
The ancient parasite has perfectly adapted itself to humans. “They are 100% dependent and cannot do anything outside of the human body,” he said. To leave it, they have to be “200% sure” that they’ll find a new breeding ground and food source, not a decision to be taken lightly.
But they are also canny little critters: Case in point, the long lag between infestation and itching. “We are always running one to two months behind the louse,” Mumcuoglu said, with evident admiration in his voice for this evolutionary marvel.
In terms of treatment, he recommends only one product, Hedrin Once Spray Gel. More important is daily combing, for 14 days. The technology is basically the type of comb found in Masada from 2,500 years ago.
Nits, the empty egg shells from the lice, can stay on hair for up to eight months, he said, and are often mistaken for signs of an infestation. Not so; they merely indicated that a child once had lice, but does not necessarily still have them. Combing can help with the nits as well as the live creatures. Unlike the policy in many international schools, he cautions against using any kind of treatment product — especially kerosene — unless actually spying a living organism, rather than nits.
Through daily combing, our household’s infestation seems to be eradicated now. But as any parent knows, that doesn’t stop a new visitor from arriving immediately. (Believe me, I know.)
Mumcuoglu said that he is careful during his often daily work with lice and their hosts not to become infested. However, he is not overly zealous about cleaning if infestation does occur: Since lice cannot live more than 15-24 hours without a human host, he doesn’t insist upon laundering bedding and towels, or spraying beds, sofas, and carpets with toxic pesticides.
“I have a huge amount of respect for lice as a living organism. If you leave your emotional, psychological problems aside, you look to the louse and see so many wonderful characteristics,” said the scientist, citing mysterious communication via pheromone secretions, among other marvels.
“We are doing so many things to get rid of them, but I can guarantee they will continue surviving for many many hundreds of years to come,” he said.
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