Where did pubic lice originate. How did humans acquire pubic lice from gorillas. What does this reveal about human evolution and primate interactions. When did humans start losing body hair.

The Unexpected Origin of Human Pubic Lice

Recent research has uncovered a fascinating link between humans and gorillas – the origin of pubic lice. Contrary to previous assumptions, scientists have discovered that humans acquired pubic lice from gorillas approximately 3.3 million years ago. This finding not only sheds light on the evolutionary history of these parasites but also provides valuable insights into human evolution and early hominid lifestyles.

The Gorilla Connection

How did humans come to host gorilla lice? The transfer likely occurred through non-sexual means. Researchers suggest that early humans may have contracted the lice by sleeping in gorilla nests or consuming gorilla meat. This revelation challenges previous notions about the origins of human parasites and highlights the complex interactions between early hominids and other primates.

Unique Lice Patterns in Humans and Primates

Humans stand out among primates due to their unique lice infestation patterns. While chimps only have head lice and gorillas only have pubic lice, humans host both types. This distinctive pattern has intrigued scientists and prompted further investigation into the evolutionary history of these parasites.

The Two Types of Human Lice

• Pediculus: Found on the head and body
• Pthirus: Pubic or crab lice

Why do humans host two types of lice while other primates only have one? This unique situation provides valuable clues about human evolution and the adaptations that set us apart from our primate relatives.

Lice as Windows into Human Evolution

The study of lice offers a unique perspective on human evolutionary history. Given the scarcity of early human fossils and the challenges in obtaining ancient DNA samples, parasites like lice serve as valuable indicators of early hominid lifestyles and evolutionary changes.

The Importance of Parasites in Evolutionary Studies

How do parasites contribute to our understanding of human evolution? These tiny organisms have coexisted with humans and our ancestors for millions of years, adapting alongside us. By studying their genetic makeup and evolutionary patterns, scientists can infer information about human migration, physical changes, and interactions with other species.

The Timing of Human Body Hair Loss

The acquisition of pubic lice from gorillas provides intriguing insights into the timing of human body hair loss. The migration of these lice to the pubic region suggests that humans had already lost much of their body hair by 3.3 million years ago.

Evolutionary Implications

What does the presence of pubic lice tell us about human evolution? The specialization of these lice to the pubic region indicates that other areas of the human body had become unsuitable habitats, likely due to the loss of dense body hair. This aligns with theories about human adaptation to savannah environments and the development of more efficient thermoregulation through sweating.

Lice Transfer and Host-Switching Mechanisms

The transfer of lice from gorillas to humans exemplifies the process of host-switching in parasites. This phenomenon is not unique to humans and gorillas but occurs in various bird and mammal species.

Conditions for Successful Host-Switching

What conditions are necessary for parasites to successfully switch hosts? Direct physical contact or very recent proximity between species is crucial. In the case of gorilla lice transferring to humans, scenarios such as humans sleeping in recently vacated gorilla nests or handling gorilla carcasses during hunting or scavenging activities could have facilitated the transfer.

Implications for Understanding Disease Transmission

The study of lice host-switching provides valuable insights into the broader field of disease transmission between species. Many emerging infectious diseases that affect humans have origins in other animal hosts.

Lessons from Lice

How can the study of lice inform our understanding of disease transmission? By examining the factors that enable parasites like lice to successfully switch hosts, researchers can gain insights into the mechanisms that allow other pathogens to cross species barriers. This knowledge is crucial for predicting and potentially preventing future zoonotic disease outbreaks.

Research Methodologies and Techniques

The study of lice evolution and host-switching involves a combination of advanced scientific techniques and collaborative efforts among researchers.

DNA Analysis and Fossil Data

How do scientists determine the evolutionary history of lice? Researchers extract DNA from lice collected from various primate species and compare it with fossil data from humans and gorillas. This analysis allows them to estimate when different lice lineages shared common ancestors and when host-switching events occurred.

Collaborative Field Work

The research involves collaboration between scientists collecting lice samples from primates in wildlife sanctuaries and laboratory teams analyzing the genetic material. This interdisciplinary approach combines field work, molecular biology, and evolutionary analysis to piece together the complex history of human-parasite interactions.

Broader Implications for Primate Evolution and Ecology

The discovery of gorilla-to-human lice transfer has implications beyond parasitology, offering insights into primate evolution, ecology, and behavior.

Early Human-Gorilla Interactions

What does the lice transfer reveal about early human-gorilla interactions? The successful transfer of lice suggests that early humans and gorillas had significant ecological overlap. This could include shared habitats, resource competition, or potentially even instances of early humans scavenging or hunting gorillas.

Evolutionary Adaptations

The specialization of lice to different body regions in humans and gorillas highlights the divergent evolutionary paths of these closely related primates. It underscores how seemingly minor adaptations, such as changes in body hair distribution, can have cascading effects on the ecology of associated species.

As research in this field continues, scientists hope to uncover more details about the intricate relationships between primates and their parasites, further illuminating the complex tapestry of human evolution and our place in the primate family tree.

Human pubic lice acquired from gorillas gives evolutionary clues – Research News

New research indicating early humans acquired public lice from gorillas about 3.3 million years ago sheds new light on when humans started to lose their body hair as they migrated out of the trees and onto the savannah.

Pthirus Gorrilae louse magnified

Florida Museum photo by David Reed

Humans most likely got the gorilla’s lice from sleeping in their nests or eating the giant apes, said David Reed, assistant curator of mammals at UF’s Florida Museum of Natural History and one of the authors of the research published in the BMC Biology journal.

About 3.3 million years ago, lice found on gorillas began to infest humans, Reed said. That they took up residence in the pubic region may have coincided with humans’ loss of hair on the rest of their bodies and the lack of any other suitable niche, he said. Reed and his co-workers’ research stemmed from their fascination with humans’ unique position among primates in being host to two different kinds of lice: one on the head and body (Pediculus), which has become the bane of many schoolchildren, and pubic or crab lice (Pthirus). In contrast, chimps have only head lice and gorillas pubic lice.

Understanding the history of lice is important because the tiny insects give clues about the lifestyles of early hominids and evolution of modern humans, Reed said. Because the human fossil record is patchy and finding early DNA samples is extremely difficult, parasites such as head lice, pubic lice, tapeworms and pinworms that have existed for millions of years provide valuable clues, he said.

“These lice really give us the potential to learn how humans evolved when so many parts of our evolutionary history are obscure,” he said. Lice also can serve as a model in understanding how parasites move from one species to another, Reed said.

Pthirus Pubis

Photo by Vincent S. Smith

“If you look at emerging infectious diseases that affect humans all over the world, most have their origins on some other host before threatening humans,” he said. “Studying what it takes for a parasite to be successful in switching hosts adds to our knowledge about what makes a good host for the spread of disease. ”

Working with other scientists who collected lice from primates in Ugandan wildlife sanctuaries, the research team extracted DNA from the lice and used fossil data from humans and gorillas to estimate how long ago these two types of lice shared a common ancestor.

In particular, the researchers looked at whether pubic lice developed on their own in humans or whether humans acquired them from gorillas. They believed humans were more likely to have had lice all along because this was a simpler explanation than acquiring lice from gorillas, but they were proved wrong. It is not unusual for lice to switch hosts, with this occurring in both birds and mammals, but they need either direct physical contact or very recent contact to do so, Reed said. In this specific case, the parasite might have been transmitted to humans sleeping in a depression in the ground where a gorilla had slept and nested the night before or even by humans feeding on gorillas, he said.

“Unfortunately, even today among modern humans there’s a bush meat trade where gorillas are killed for their meat,” he said. “If archaic humans were butchering or scavenging those animals 3.3 million years ago, it would be a simple thing to transfer those lice from prey to predator.”

Because humans and gorillas are so closely related and have so many potential interactions of a nonsexual nature, it would have been less likely for the lice to have been transmitted through sexual intercourse, he said.

Reed did the study with postdoctoral researcher Jessica Light at the Florida Museum of Natural History and zoology graduate students Julie Allen and Jeremy Kirchman.

Gorillas Gave Humans ‘The Crabs

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image of gorilla.
(Image credit: morguefile.com)

Humans caught pubic lice, aka “the crabs,” from gorillas roughly three million years ago, scientists now report.

Rather than close encounters of the intimate kind, researchers explained humans most likely got the lice, which most commonly live in pubic hair, from sleeping in gorilla nests or eating the apes.

“It certainly wouldn’t have to be what many people are going to immediately assume it might have been, and that is sexual intercourse occurring between humans and gorillas,” explained researcher David Reed of the Florida Museum of Natural History. “Instead of something sordid, it could easily have stemmed from an activity that was considerably more tame.”

Humans are unique among primates in that we host two different kinds of lice—one on our heads and bodies (Pediculus), the bane of many schoolchildren, and pubic lice (Pthirus). In comparison, chimpanzees have only head lice and gorillas only pubic lice.

• See Also: Human and Chimp Ancestors Might Have Interbred

Parasite history

Understanding the history of lice is important because they and other parasites yield valuable hints about the lifestyles of human ancestors and the evolution of modern humans, Reed said.

“Our own history is written in the DNA of parasites as well as ourselves, and by studying both we can come to a better, more complete understanding of our evolutionary history,” Reed told LiveScience. “These lice really give us the potential to learn how humans evolved when so many parts of our evolutionary history are obscure.”

Investigating lice can also help in understanding how parasites move from one species to another, Reed added.

“If you look at emerging infectious diseases that affect humans all over the world, most have their origins on some other host before threatening humans,” he said. “Studying what it takes for a parasite to be successful in switching hosts adds to our knowledge about what makes a good host for the spread of disease.”

Collecting lice

In collaboration with scientists who collected lice from primates in Ugandan wildlife sanctuaries, Reed and his colleagues extracted DNA from the parasites and used fossil data from humans and gorillas to estimate how long ago these two kinds of lice shared a common ancestor.

“The hardest part was collecting the gorilla lice, and without the help of our colleagues Chris Whittier and Michael Cranfield at the Mountain Gorilla Veterinary Project, we wouldn’t have been able to do this project at all,” Reed said. “They monitor the health of gorillas in Uganda, Rwanda, and the Democratic Republic of Congo.  Through their monitoring program they have been able to collect ectoparasites, including lice.”

The researchers expected humans simply developed pubic lice on their own since this was a simpler explanation than acquiring the parasites from gorillas. However, they were proved wrong.

The evidence suggests gorilla lice began infesting humans about 3.3 million years ago. In contrast, humans and gorillas diverged in evolutionary time about 7 million years ago. The fact the lice took up residence where they did may have coincided with human loss of most hair on the rest of their bodies and the lack of any other suitable niche to live, Reed said.

The researchers detailed their findings in the latest issue of the journal BMC Biology.

Bush meat link

For this species jump to have occurred, the ancestors of humans and gorillas “must have been in the same place at the same time, which was not known before,” Reed added. “The fossil record of gorillas in particular tells us very little about the gorilla lineage at the time this switch took place 3.3 million years ago.”

These findings do not mean the lice were transmitted by monkey business between humans and gorillas.

“Unfortunately, even today among modern humans there’s a bush meat trade where gorillas are killed for their meat,” he said. “If archaic humans were butchering or scavenging those animals 3.3 million years ago, it would be a simple thing to transfer those lice from prey to predator.”

“This paper makes one’s imagination run wild, giving graphic new meaning to that ‘800 pound gorilla,'” biologist Dale Clayton at the University of Utah said in a prepared statement. “However, as the authors point out, the inferred host switch of pubic lice from gorillas to humans did not require sexual contact. Human pubic or ‘crab’ lice get transmitted between people on bath towels all the time. So it is easy to imagine that gorilla lice could have transmitted to humans via shared sleeping quarters, or predation, as the authors suggest. “

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Charles Q. Choi is a contributing writer for Live Science and Space.com. He covers all things human origins and astronomy as well as physics, animals and general science topics. Charles has a Master of Arts degree from the University of Missouri-Columbia, School of Journalism and a Bachelor of Arts degree from the University of South Florida. Charles has visited every continent on Earth, drinking rancid yak butter tea in Lhasa, snorkeling with sea lions in the Galapagos and even climbing an iceberg in Antarctica.

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Pediculosis pubis – health articles

11/10/2022

Pediculosis pubis (phthyriasis) is a parasitic skin disease caused by pubic lice. Pubic lice prefer the genital area (pubis, scrotum, perineum), hair around the anus, armpits, since these areas contain a large number of apocrine glands, which are specifically oriented to the sense of smell of pubic lice. Mustaches, eyebrows, eyelashes and scalp hair in children are less commonly affected.

Causes

Most often, pubic louse is transmitted through sexual contact, contact with the skin of a sick person during sexual intercourse, and it can also happen when using shared clothing, bedding, baths, showers.

If a sexual infection has occurred, lice settle most often on the pubic area, perineum, around the anus. At household – on the hair of the chest, axillary region, eyelashes. In children, cases of phthiriasis are also described on the scalp. But this is all conditional: if the disease is not treated, then reproduction and migration of pubic lice throughout the body is possible. When using a common towel, bed, it is possible that lice will settle on the pubis.

Symptoms

Pediculosis pubis begins with an incubation period, when there are no symptoms yet, but pubic lice have already settled on the human body. The incubation period of pubic pediculosis usually lasts about a month.

After the end of the incubation period, pubic pediculosis is manifested by several symptoms, the most significant of which is skin itching at the site of the introduction of lice into the skin of the patient. Most often it is pubic itching, but other parts of the body can also be involved in the process: the thighs and torso (especially in people with excessive hair), as well as the beard and mustache. The intensity of skin itching can be different: sometimes a person does not even notice it, and sometimes, especially at night, the itching is unbearable. Itching in the area affected by pediculosis usually leads to the fact that the patient combs the skin, and because of this, irritation and redness of the skin occur, eczema appears, and secondary infections enter the body through scratching.

In addition to skin itching, a sign of pubic pediculosis can be considered as blue or shadow spots appearing on the skin with a diameter of up to 1 cm, which quickly disappear. The reason for their appearance can be either small hemorrhages when sucking blood by lice, or the deposition of the secretion of their salivary glands. Such spots most often appear on the abdomen, chest, lateral surface of the trunk and thighs, that is, where the hairline is not thick and the spots are easy to notice.

Sometimes an allergic rash is added to the symptoms of lice pubis. An undoubted sign of pubic pediculosis is the detection of pubic lice themselves or their larvae on the skin or underwear.

Diagnosis

Pediculosis pubis is easy to diagnose. Firstly, the patient’s complaints with pubic lice are very characteristic, and secondly, lice or nits themselves are almost always found on linen or on hair in the lice-affected area of ​​the body.

Therefore, the main method for diagnosing pubic pediculosis is to examine the patient. Adult parasites can be seen with the naked eye, but more often a magnifying glass or loupe is used for this. Ploshchits are easier to spot after they drink blood, which gives them a “rusty” coloration.

Treatment

Pediculosis pubis is treated with special ointments, shampoos or sprays containing drugs that kill insects. As a rule, a single application of the drug is enough. If there are a lot of lice, then the patient is advised to shave off the hair in the affected area of ​​​​the body. Sometimes in such cases, about a week after the first use of the drug, a second treatment is carried out.

Simultaneously with the treatment, it is necessary to change underwear and bed linen, and boil or machine wash the old linen at the maximum temperature and then iron it on both sides. During the treatment of pubic pediculosis, both underwear and bedding are changed daily.

Pubic lice are on the verge of extinction

Pubic lice are on the verge of extinction, according to Bloomberg. Scientists are sure that bloodsuckers have become victims of the widespread fashion for Brazilian hair removal. At last count, more than 80% of male and female college students in the US are trying to get rid of most of their pubic hair. And at the main sexual health hospital in Sydney, Australia, doctors admit that since 2008 not a single woman has come to them with a complaint of pubic pediculosis. And the number of men with such a problem decreased by 20%.

“They used to be very common, but now they are very rare,” Basil Donovan, head of the Department of Sexual Health at the Kirby Institute at the University of New South Wales in Australia, talks about pubic lice. “Sure, it’s better to take care of yourself.” According to him, if it goes on like this, it will be possible to put an end to the flats for good.

Previously, insects, which not only interfere with life, but also make their hosts vulnerable to sexually transmitted diseases, were fought with the help of strong toxic drugs developed during the Second World War. Then the doctors found out that pests can be overcome simply by destroying their natural habitat.

The added bonus of beauty treatments was used by hair removal companies in their ads. According to economists, in the past few years, the depilation market has been growing steadily by 7-8% per year.

For the development of aesthetics and the disappearance of pubic lice, apparently, we should thank the seven sisters from Brazil. Jonis, Josly, Janea, Jois, Jurasi, Jussara and Judezia Padilla are accustomed in their homeland to do bikini waxing on a regular basis – otherwise how will you appear on Brazilian beaches in open swimsuits? In the late 80s, women moved to the United States and opened the J Sisters nail salon in New York, and at 1994 introduced a new service – waxing. Since then, the rapid rise of their career and fashion for the absence of excess vegetation on the body began. Up to 200 clients a day came to the procedure, including stars.

“Women come to us for Brazilian epilation, and men for sunga wax, a procedure that removes up to 90% of hair in intimate places,” said Jonis Padilla. “Hygiene and comfort are the two main reasons why customers come back to us time after time.” “We didn’t think we’d be so successful. And even more so, we did not expect that epilation would help in the fight against lice, ”she added.

At the same time, scientists are seriously concerned about the possible extinction of this insect species. “Pubic hair care has led to severe depletion of pubic lice populations,” says Ian Burgess, a medical entomologist at the Insect Research Company in Cambridge, England. “Because of the depilation, flat people face an ecological disaster.” Echoed by sexual health and HIV prevention consultant Janet Wilson: “The destruction of the habitat of pubic lice is gaining momentum, this species is under threat.”

Other researchers say hair removal is a danger to humans, perhaps as much as lice. According to scientist Cooper Robins from the University of Sydney, hair removal can cause trauma to the skin and destroy the protective barrier, and non-sterile depilation increases the risk of infection.