What is the human flea, what does it cause and what do its stings look like?

The human flea is a parasitic insect that is not only annoying. It is a worldwide nuisance to humans and animals alike. What does a flea look like and what are its bites? Can fleas be dangerous?

In total, there are 2,000 species of fleas in the world.

Everyone thinks of a flea as a parasitic insect attached to the skin between the fur of their pet.
That's how most people think of it. But fleas also like to feast on the blood of birds, other mammals and even human blood.

You thought fleas didn't go after people?

Wrong!

Fleas are not picky, and several of them like to feast on human blood.

Their prevalence is higher in areas with a low standard of living and poor hygiene.

Interesting:
A 5,000-year-old ice mummy known as Ötzi was found in the Italian Alps.
Ötzi was not the only artifact discovered, however.
Two human fleas (pulex irritans) were also found on his mummy.

The most common flea hosts:

• Dogs
• cats, feral cats.
• poultry
• various species of birds
• rabbits
• sheep
• cows
• pigs
• foxes
• wolves
• coyotes
• moles
• badgers
• rodents

What is a flea? How do you recognize it and what do its eggs look like?

Parasites include mosquitoes, stinging flies, vipers, ticks, lice, aphids, human flea, dog flea, cat flea, scabies, flatworm, follicular skin worm, trombicula and simulides.

Read also the articles:
Mosquito bites: What do they choose their victims by and how can you protect yourself?
How do head lice manifest in children? What do they look like and how to remove them
Dobedbug bites botheryou + What is the life span of a bedbug and what does it hate?

A flea is also a parasite that uses humans or their blood as a food source in a specific way.

The flea (Lat. Siphonatera, Aphaniptera) is a species of small, globally distributed wingless insect.

The size of this rusty brown to black insect ranges from 1.5 to 3.5 mm.

The head of the flea is hypognathic. This results in oral organs with well-developed jaws located at its base. This location is adapted for stinging and sucking.

On its upper part are truncated antennae partly embedded in the ectoskeleton.

They also have small eyes, but these may be completely absent in some cases.

It is not yet entirely clear whether the eyes of fleas are merely a remnant of the original compound eyes, or whether they are merely a grouping of several simple primitive eyes. However, scientists are leaning more towards the former.

The entire head is covered with backward-facing eyebrows that make it easier for fleas to move through the host's fur or hair.

The shape and body of the flea is evolutionarily adapted to an ectoparasitic lifestyle. That is, it is flattened at the sides.

At the back of the flattened body are the rear jumping legs, which help them jump greater distances.

Interesting:
Not only because of the jumping legs, but also because of a special protein called resilin, fleas can jump up to 18 cm in height and more than 30 cm in distance.

Developmental stages of the flea

The flea is a holometabolous insect with a four-part life cycle. The flea life cycle consists of several developmental stages.

Table of developmental stages of the flea:

Stage I - Eggs are secreted into the environment, often on the host body by the female flea. The female lays approximately 400 to 500 eggs approximately 2 days after feeding on blood. They reach a size of about 0.5 mm. They are pearly white in colour and oval in shape.

Stage II - Larvae hatch from eggs on approximately day 4. They have an oval, slightly elongated worm shape and are 0.6 mm in size. They are white to slightly yellow in colour and feed on organic debris in the environment, usually faeces of the parents.

Stage III - Pupae are the next stage of the flea. They develop from larvae. Pupae are about 2 mm in size, occur in cocoons and are surrounded by environmental debris such as sand, dust particles.

Stage IV - Adults are adult forms of fleas that hatch due to shocks, vibrations and temperature increases. They feed on the blood of the host (warm-blooded animals). They live less than 2 years.

Can fleas also infest humans?

Man is not and never has been the primary host of fleas. However, he is the only primate on which fleas have begun to parasitise secondarily.

They primarily parasitize birds and other mammals that have a permanent nest, burrow, or den. These are mainly rodents, insectivores, or bats.

Therefore, the name human flea or house flea may seem like a misnomer. The term was introduced by the Swedish naturalist and founder of taxonomy Carl Linné in 1758.

Interesting:
Only about 5% of fleas live directly on the animal.
They live and parasitise the animal for about a week and then stay in the vicinity. 95% of fleas live in close proximity to the infested animal (nest, aviary...).

In particular, the human flea has been essentially eradicated.
Humans can be infested by dog or cat fleas, which parasitise these animals. They only jump to humans if they have no other host.
Therefore, human flea infestations are only sporadic.

What causes fleas to parasitize humans?

The domestication of animals has rapidly contributed to secondary parasitism of fleas on humans.

It is the animals that fleas feed on. By domesticating and domesticating them, humans have not only brought help, a food source or a pet, but also a hidden parasite.

We are also seeing an increased incidence of fleas in areas with low levels of public hygiene.

Which fleas most commonly infest humans?

• Human flea (Pulex irritans) - This is one of the fleas that most commonly infest humans. It is 2 to 3.5 mm long. It is commonly found on wild and domestic animals, from which it then jumps to humans.
• Dog flea (Ctenocephalides canis) - This is an alien parasite on dogs, as its name implies. It also measures 2-3.5 mm. It is rarely found on humans, but is possible if the dog is massively flea infested. It has limited survival on other hosts. It can infect humans with tapeworms in the short time it is present.
• Cat flea (Ctenocephalides felis) - Predominantly attacks cats, but can also occur on dogs and humans in the absence of a more suitable host. It is much smaller than the human and dog flea. It grows to a size of 1-2 mm. It is less visible in the dense fur of cats. It dies within a few hours outside its host.
• Hen flea (Ceratophyllus gallinae) - This species of flea primarily attacks poultry, but its original host was probably titmice. It can jump to other birds and mammals, but it is not clear how long it survives on them. Hen fleas are brown in colour and reach a length of approximately 2-2.5 mm.
• Mole flea (Hystrichopsyla talpae) - It is relatively large, growing to a length of 6-7 mm. It is characterised by not even having primitive eyes. It lives mainly in mole burrows, but can also be found in burrows of other small mammals. Due to their range, its transmission to humans is rare.

Interesting fact:
Sometimes a flea infestation in a dog is visible to the naked eye (the direct presence of fleas in the fur), other times it manifests itself by frequent scratching and biting of the animal.
The scratching is caused by itching. This is triggered both by the movement of the fleas, but also by the wounds that the fleas cause when sucking blood.
At the same time, they release saliva containing substances into the wounds that prevent the blood from clotting. This intensifies the itching sensation.
When an animal is heavily infested with fleas, it scratches so hard that it causes scabbing of the healing wounds with subsequent loss of fur.

Flea bites, why do they happen?

Fleas feed on the blood of their host. Their requirements for blood quality are minimal.
They only carry cold blood from a dead animal or human.

Regardless of the requirements, fleas would not be able to survive and reproduce without sucking their blood food.
They are capable of sucking much more blood than they can digest.

Interesting:
Some flea species are able to survive without food for only a few hours (cat flea), others for almost a year (human flea).

They use oral organs with developed jaws at the base of the head to suck blood.
These are adapted for biting and then sucking blood.

What do flea bites look like?

Flea bites are technically called pulicosis.

After a person is bitten by a flea, a lesion appears in the skin at this site in the form of a small red (bloody) spot that forms after the skin is punctured/punctured.

The skin around the bite is also damaged by contact with the flea's excreta - toxic-acting, sometimes germ-carrying germs.
The skin is slightly swollen locally, reddened and characterised by unpleasant itching.

Usually several bites are observed side by side, usually 3 bites. This is also the case with bed bugs. However, bed bug bites are more numerous and occur in a row.

Bites are most common around the waist, armpits, in the knee creases and around the ankles.
They can occur equally on exposed and unexposed parts of the body.

They usually disappear in about 3 days. In case of local infection or allergic reaction, they may persist longer and cause intense itching and soreness.

Can fleas transmit diseases?

Some internet sources state that fleas cause bites but do not transmit any diseases.

However, this statement is incorrect!

If it were true, millions of people would not have lost their lives in plague epidemics. Fleas were the intermediate hosts of the Yersinia pestis bacterium. They transmitted it from rats to humans, where it caused a disease also known as the Black Death (plague).

Interesting:
Human fleas infected with Yersinia pestis have been found in the homes of people affected by plague epidemics in various parts of the world.
The recent plague epidemic in Madagascar was caused by the transmission of the bacterium to humans by fleas, which were present in up to 98% of the homes of those infected.
Drancourt, Houhamdi and Raoult even claim that fleas play a major role in plague epidemics.

How is the transmission of the disease from fleas to humans?

Fleas do not have high requirements for blood delicacies.

Regardless of blood type, Rh factor or presence of germs, they will suck up anything that comes their way.

They don't just eat the blood of a dead host. They seek out a new host to survive.

This means that if a flea sucks the infected blood of a sick animal or human, it also sucks any pathogens circulating in its bloodstream (bacteria, viruses).

The germs in the flea's body don't die. They not only survive, but they continue to reproduce.

When repeatedly sucking on the body of a new host, these pathogens enter its bloodstream through the puncture wound and cause infection.

What diseases do fleas most commonly transmit?

The most common diseases or conditions that a flea bite can cause are undoubtedly allergic reactions. These occur even in cases where the flea has not been infected.

Infected fleas can transmit various viral or bacterial infections.

The transmission of other parasites to the host is no exception.

1. Epizooonoses are a group of skin diseases caused by parasites that are transmitted to humans from the external environment, i.e. fleas. They not only live on human skin but also cause skin manifestations. Most commonly, they cause stinging, redness and itching.
2. Allergic reactions are manifested by a disproportionate skin reaction to a flea bite in a sensitised individual. The allergy occurs to the saliva and excreta of the flea. It is manifested by more extensive redness of the affected area, itching of the skin and scratching. The resulting inflammatory reaction causes the pimple to persist on the person's body longer than usual. Serious anaphylactic reactions following flea bites have not been described.
3. Dermatitis is an inflammatory skin disease that can arise as a result of an allergic reaction (allergic dermatitis) but also on a non-allergic basis (non-allergic dermatitis) as a result of a secondary infection arising in the wound after a bite. It is a large erythematous lesion characterised by intense itching, reddening of the skin with the presence of blisters, even peeling of the skin.
4. Borreliosis is a disease that in most cases is transmitted by an infected tick. However, it can also be transmitted by other blood-sucking insects, including fleas. Transmission occurs when a flea is infected with Borrelia burgdorferi. Borreliosis manifests itself with symptoms ranging from flu-like to severe neuropathy. It is usually associated with the appearance of erythema migrans (migratory patches), which are red and pale towards the centre.
5. Meningitis is an inflammation of the meninges caused by meningococci. Like Lyme disease, it is mainly transmitted by ticks. Transmission by fleas is rare. Meningitis is manifested by high fever, severe headache, neck pain, vomiting and petechiae on the skin.
6. Plague is not a disease of the past, although at the time it caused major epidemics and caused millions of deaths. Plague is still present in the world today. Sporadically, it causes minor epidemics in countries with a lower standard of living. The most recent epidemic occurred a few years ago in Madagascar. In most developed countries, the disease is not currently present. However, it is important to be informed and cautious, especially when travelling to areas at risk. Plague is a bacterial disease caused by the microbe Yersinia pestis, which is most commonly infected in rodents (rats). It is transmitted to humans by fleas.

Read more:
The largest epidemics and pandemics in human history

How to get rid of fleas?

When disposing of fleas and their eggs, it is important to remember that only 5% of fleas are found directly on the human body.
The vast majority are found in their host's environment.

Eradication and disinfestation should therefore target the person but also the environment.

I have fleas! What should I do?

Hygiene, hygiene and more hygiene!
Thorough hygiene of the whole body is extremely important for this parasite.

Shaving the whole body is essential. Fleas are most often found around the hair and hair (hair, eyebrows, eyelashes, armpits...).

Cutting the hair is a radical step that is mostly undertaken by men, and only in the case of a severe flea problem.
For women, this step is unacceptable and in most cases not a necessity.

Nowadays, there are many medicated shampoos that relieve itching. They treat not only the hair but also the scalp.
It is important not only to wash but also to comb the fleas out of the hair with a thick comb while using conditioner, oils or pyrethrins.

Cleaning a flea infested environment

For smaller infestations, fleas can be got rid of by thoroughly cleaning the entire living space, with an emphasis on vacuuming carpets and sofas, or brushing.

Personal clothing should be washed on a higher setting.

Disinfestation

Disinfestation is a set of several measures that are carried out to destroy harmful insects.

These eradication methods usually use chemical means, but also include biological and physical methods.

Disinfestation should be carried out systematically, in a planned manner and after a thorough survey of the infested environment.

It is carried out by aerosol, spraying, coating, dusting and decomposition of baits.