In recent years we are seeing instances throughout the year. Head Lice - The Facts: According to Hennessy, if you want to get rid of nits and head lice you need to understand the life cycle which works like this:. Does my child have nits? In order to distinguish between the two, comb the hair over a black cloth — dandruff will appear to be mostly see-through and the eggs or nits will be more coloured or dense.
Also if you can easily pull what you find off the hair with your fingers, its likely to be dandruff. They are tear drop shaped and are brownish in colour. The Secret of Success for Treating Lice? First thing is to meticulously and regularly comb through the hair. The added benefit was she had beautiful shiny hair after treatment and no chemicals! I can remember after bath time on a Friday a small amount of conditioner was put into our hair and our hairs were fine-combed for lice. Secondly where an infestation was detected, all the family was treated.
These used correctly and in conjunction with a fine tooth comb should solve the problem. Prevention is better than Cure:. This is an ammonia free colour that is slightly acidic. Headlice HATE acid. It will last in the hair for up to 30 shampoos. The rules unfortunately vary greatly from school to school.
In Germany, for example, children are not allowed to come to school if they have nits. Archaeologists have discovered dozens of grave sites filled with pottery, jewelry, and well-preserved clothing and textiles. Looters had destroyed the bodies but had spared the heads, which were covered in braids of thick black hair. According to radiocarbon dating they probably died around , almost years before Christopher Columbus arrived in the Americas. Early paleontologists had few ways of determining the age of their discoveries.
Head lice - Lifestyle News
The best they could do was date fossils relative to other fossils based on the layer of rock they were found in. In the s that finally changed when chemists Willard Libby and James Arnold developed a process they called radiocarbon dating. Radiocarbon dating is an ingeniously simple idea that makes it possible to determine the age of bones and fossils with an accuracy of a hundred years or so.
Through eating, drinking, breathing, or photosynthesis, all organisms absorb the radioactive isotope carbon, which is created from nitrogen when cosmic radiation strikes the atmosphere. When an organism dies, it stops absorbing carbon, but the radioactive isotopes it has taken in through its life continue to decay at a consistent rate. Archaeologists can determine how long ago something lived by measuring how much carbon is left. The less carbon, the older the object. Archaeologists can use uranium and other radioactive elements to date even older remains but with less accurate results.
She bottled the lice up and eventually gave them to her friend Katharina Dittmar, a German evolutionary biologist who was then working on a postdoc about parasites.
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Dittmar incorporated the find into a paper describing which diseases might have plagued the Chiribaya culture. A few years later Dittmar was working at the University of Buffalo when another evolutionary biologist named David Reed paid her a visit. Dittmar mentioned that she had a vial full of hundreds of ancient, shriveled lice from Peru.
Reed asked if he could try to sequence their DNA, and Dittmar handed over the vial. Reed, now associate director for research and collections at the Florida Museum of Natural History, has no special interest in lice; instead he uses them to study the early history of their hosts. Thanks to a quirk of the parasite-host relationship, tens of thousands of years later Reed wanted to use that knowledge to fill in gaps of human history. How did humans migrate across the planet? What events jump-started the spread of typhus and other parasite-borne diseases?
These are questions Reed hoped to answer with lice. Reed first learned about the unique nature of mammal-parasite relationships during graduate school at Louisiana State University. While analyzing parasites living on pocket gophers in New Mexico and Texas, he realized that each lineage of pocket gopher hosts its own unique lineage of louse. A lineage of gopher or louse has enough genetic differences from its relatives to be distinct but not enough to be categorized as a new species.
Reed knew that lice had been living on pocket gophers for millions of years. He also knew that pocket gophers had evolved and changed during that time and that lice cannot survive long away from their hosts. If lice coevolved with gophers, they must also have coevolved with other species they infest, including humans. But in this case the lice were the pollen and humans were their world.
Who can get head lice?
Not long after completing his PhD, Reed moved to the University of Florida, where he started a database of louse DNA collected from all over the planet. But the Peruvian head lice represented his first chance to study louse DNA from the past. His equipment was designed to extract DNA from fresh lice, and he had no idea of the condition of the 1,year-old specimens.
Reed could easily identify six hairy legs sprouting from flat abdomens about the size of a sesame seed. The desert climate had dried them out so quickly after death that their exoskeletons shrank, acting as protective pouches for their soft innards and DNA. Essentially, their insides had been hermetically sealed by the dry air. Humans are unique in that we host three forms of lice. Head lice have small claws that are perfectly shaped to allow them to climb up and down shafts of our hair, where they lay eggs. Several times a day they have to descend from their perch to feed on the scalp of their host.
European men in the s shaved their heads and wore powdered wigs in part to combat the pests. However, they shaved their heads not to thwart lice, but rather to better fit the wigs, which were periodically boiled and brushed to remove the lice. The second kind of louse that makes a home on humans is the clothing louse also known as the body louse.
These insects are a little larger than head lice and lay their eggs in practically every kind of fabric humans come into contact with. The third type of louse lives primarily in the pubic region and is spread through sexual contact. Resembling bulky crabs with huge claws designed to grip thick hair, their origin is perhaps the most perplexing of all three species: millions of years ago our forebears inherited them from the ancestors of gorillas.
Reed carefully sliced them in half and extracted and analyzed their DNA. Then he compared it to the genetic data he had collected from modern lice all over the world. This is where things get a little bit complicated. There are three types of lice that live on humans: head, clothing, and pubic lice.
These parasites are divided into a handful of major genetic groups, or clades. Perplexingly, these clades do not line up with the head, clothing, and pubic lice categories. Although there are at least five clades, only two of them are widespread enough to be relevant to this story. Clade A lice are common on every continent and consist of both head and clothing lice.
Clade B lice are limited to living on human heads and originated in the Western Hemisphere, but have since spread to Europe and Australia. These categories can be difficult to keep straight. It might be helpful to think of clade A as global lice everybody has them and they live all over the body and clade B as American lice that prefer the head.
At some point in history each clade became separated from the others for long enough to develop its own unique DNA. Think of finches in the Galapagos and how their beaks evolved to harvest the food available on their respective islands. Yet for lice the differences in their genes that define the different clades are not evident at a glance and can only be detected by sophisticated computer programs that find patterns over entire genomes.
Although clades A and B are currently found in the Western Hemisphere, Reed knew they were so genetically distinct that they must have diverged tens of thousands of years ago.
A Brief History of Head Lice
Where did clades A and B come from, and which one arrived in the Americas first? Reed hoped the answer to that question might help resolve disputes over how and when humans migrated to the Western Hemisphere. Using a computer program that calculated the rate of mutations and change between the two species, he concluded that the two main clades of lice, A and B, had diverged 1. Reed was perplexed: how could a species as young as humans our current anatomical form has been around for less than , years have such ancient lice?
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A article in Nature summarizing the understanding of human evolution at the time gave Reed an idea of where the ancient lice could have come from. In particular, a graphic within the article jumped out at him. It showed a proposed split between Homo erectus and the ancestors of H. That meant some major event must have happened at that time, causing two populations of hominins a term that broadly encompasses humans and our close, extinct relatives to be separated for more than a million years and leading their lice to evolve distinct genetic traits.
Reed theorized that the major event could have been when H. That gave Reed another idea. It would account for the isolated populations in the Western Hemisphere because at the time the fossil record showed that H. There is no evidence that H. The two species swapped lice before H.
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For this theory to make sense H. That meant they were living with each other and maybe even mating, a possibility that had not been previously considered. It seems like every few months scientists find new fossil evidence of ancient humans that changes our understanding of the past and makes articles like this one outdated.
Although new discoveries are piling up faster than scientists can parse them, the big question of exactly where humans came from and why we succeeded over other species remains a mystery.