FLEAS: AMAZING JUMPERS THAT CAN CARRY PATHOGENS

Have you ever seen some small dark brown bugs jumping off your pets? Those creatures might have been fleas. Fleas are insects specialized for feeding on blood, with long, strong legs for jumping and claws for holding onto your pet tightly. Fleas use many animals, including humans, as “hotels” and “restaurants”. Even if pets try to scratch and shake to kick out these unwelcome guests, it does not work! They hang on with their claws and keep eating for free. In addition to being nasty, fleas can carry diseases that they can transmit to animals when the fleas feed, or if the animal eats them accidentally. So be careful if these tiny insects decide to visit your pet’s skin! Do you want to learn more? Keep reading, and we will introduce to you some curious facts about the lives of fleas.

these organisms from the mid-Mesozoic Era, more than million years in the past.The evolution of fleas is interesting since fossils from the Jurassic period of the Mesozoic Era show that the ancestors of fleas were nasty-looking creatures and, in some cases, these ancestors looked very di erent from today's fleas [ ].The fact that they may have been on Earth since the time of the dinosaurs makes fleas fascinating insects.

WHAT DO FLEAS LOOK LIKE?
Maybe you have never seen a flea up close-you might only know them as tiny, dark brown spots jumping o your pet.Fleas are small ( .-. mm long), dark brown, oval-shaped insects with thin, flat bodies.They cannot fly because they do not have wings, but they are among the best jumpers in the animal world [ ]. Fleas have six long legs, and the hind pair is extra-long, giving fleas amazing jumping ability.Some species can jump up to times their body length.In practical terms, if .m tall children had the same jumping ability as a flea, they could jump about m into the air-the height of the Ei el Tower!Under a magnifying glass, you can see more details of the flea's body (Figure ).The body is divided into the head, thorax, and abdomen.The head is helmet-shaped, with mouthparts that are specialized for piercing the host's skin, allowing the flea to suck blood.Fleas have two eyes that can detect light and a pair of antennae.Some species have rows of spines on their bodies, called the ctenidium.A flea's CTENIDIUM Sharp and pointy spines arranged as a comb, allowing the flea to hold onto their host while they feed.
body is covered with hard, smooth plates, like armor, and they have bristles on those plates that all point in the same direction to move through the host's fur more easily.On both sides of the flea, there are pores called spiracles that the flea breathes through.Fleas also have a SPIRACLES Tiny holes that many insects use to breathe, including fleas.sensory structure called the pygidium that detects air currents.Some scientists believe that fleas may communicate with each other by producing high-frequency sounds through their spiracles.These sounds might be picked up as vibrations by the pygidium bristles of another flea.Generally, the backs of female fleas are convex (curved outwards), while males' backs are nearly straight.Male fleas have complex genitals, with the phallus (male sexual organ) normally coiled up within the abdomen [ ].When male and female fleas reproduce, the male's sex cells must reach the female's sex cells to produce eggs.Females have a structure called the spermatheca, which is responsible SPERMATHECA Kind of a storehouse where female fleas and other insects produce and keep their eggs.
for storing the sex cells that are deposited by the male flea.

NOT ALL FLEAS ARE THE SAME
At first glance, all fleas look the same in body shape and coloration, but if we look more closely, we can see that some have di erent shapes and structures.Organisms that share common characteristics and can make babies together are considered the same species.Each species SPECIES Groups of living things that look similar to each other, like dogs or birds.
is given a scientific name.Currently, more than , flea species are known worldwide, most of which infest animals, including dogs, cats, rabbits, rats, foxes, pigs, goats, raccoons, and some birds.A few flea species even infest humans [ ].

WHERE ARE FLEAS FOUND?
Most flea species live in tropical regions, where the warmth and humidity help them to develop.By hitching a ride on animals, fleas have been transported to various environments and have adapted to live in many conditions.Did you know that fleas can even live in very, very cold places like Antarctica?Although fleas prefer warm weather, there are some super-tough fleas that can infest seabirds, and they can be found in Antarctic and sub-Antarctic regions.In summary, while fleas are more common in areas with warmer climates, they are established in almost every environment on Earth.So, whether you are on a tropical sunny beach, high in a snowy mountain, deep in a humid rainforest, or a desert, there is a chance you might encounter these pesky little insects!

LIFE CYCLE OF FLEAS
Fleas go through a lifecycle that consists of four stages (Figure ): Egg Female fleas lay up to eggs per day on their host animal.Those eggs do not stick to the host and usually fall down.This means that flea eggs can be found anywhere inside our houses (for example, in carpets, sofas, or bedding) or in outdoor areas (in grass, sand, dirt, and nests).Flea eggs are tiny and hard to see, so it is almost impossible to  find one.When conditions of temperature and humidity are right, eggs hatch within a few days.

Larvae
Once the eggs hatch, they develop into larvae.Larvae look like tiny white worms, and they really do not like sunlight, so they crawl into dark, humid hiding places where they can have their favorite meal: organic matter from the environment.When the eggs do not fall o

ORGANIC MATTER
Any material or residues from a living or non-living organisms.
the host animal, the larvae feed on their parents' poop (yuck!) or skin cells from the host.

Pupae
After about -weeks of feeding, larvae start the metamorphosis into

METAMORPHOSIS
The period when an animal undergoes a transformation of their body; for example, when a caterpillar changes into a butterfly or when a pupae changes into an adult.
the pupal stage.Each larva spins a cocoon made of a silk-like material to protect itself.The cocoon is very sticky and helps camouflage the pupa.Pupae can remain in cocoons for several weeks to months since they do not have to feed and can wait until environmental conditions are perfect to emerge as adults.

Adult
The adult flea emerges from the cocoon once the weather is warm and potential hosts are nearby.At this stage, fleas are fully developed and ready to start looking for hosts to feed on for blood.Both male and female fleas take several blood meals daily.Once they enter their new home, they start the life cycle again by feeding, reproducing, and laying eggs.
Generally, adult fleas can live for or months, but they can only survive a few days or weeks without attaching to a host.The entire life kids.frontiersin.orgcycle of cat fleas, for example, usually is completed in -days.The cycle can be influenced by humidity, temperature, amount of light, and host availability.The knowledge about the lifecycle of fleas is essential for developing e ective flea control and prevention.

ARE FLEAS DANGEROUS?
Fleas can transmit pathogens, like harmful bacteria, to humans and

PATHOGENS
Very tiny germs that can make humans or animals sick.
their pets, and they can also cause itching and redness of the skin, called allergic dermatitis.Cat fleas are responsible for transmitting the bacterium Bartonella henselae to humans, which can cause an illness called cat scratch disease.In this case, the bacteria are released in flea poop when they take a blood meal from an infected cat, which usually is not sick.When the flea-infested cat scratches and grooms itself to get rid of fleas, contaminated flea poop get under its claws and into its mouth.The cat can then transmit the bacteria to humans through bites and scratches [ ].As you can see, fleas can be a health risk, and the close relationships between humans and animals create situations where these diseases are more likely to occur.In addition to bacteria, cats and dogs can be infected by parasites called tapeworms if they eat fleas that are infected with tapeworm larvae [ ]. Infected pets can have diarrhea and they usually rub their butts on the floor to show they are not feeling well.

PROTECTING OURSELVES AND OUR PETS FROM FLEAS
Controlling the presence of fleas is essential to keep humans and their pets healthy and protected from flea-borne diseases.It is not enough to control fleas only on pets-fleas, eggs, and larvae must also be eliminated in the environment.So, it is important to clean indoor and outdoor spaces to remove the fleas at all stages of their life and organic matter that feeds flea larvae.Veterinarians can prescribe anti-flea sprays, soaps or shampoos, oral medications, and collars to prevent flea infestation [ ].

TAKE HOME MESSAGE
Fleas have characteristics and a life cycle that allows them to survive in the environment and on animals.The adult fleas you may see on pets represent % of the fleas in the area where that pet lives.The remaining % of fleas are in the environment as eggs, larvae, and pupae.When these fleas become adults, they look for hosts to feed on.Therefore, to prevent flea infestations, it is important to treat pets and clean the environment where our pets live.When fleas are taking their blood meals, they transmit pathogens to animals and humans.But do not worry!Now you can recognize fleas and know how to prevent them.Be sure to inform your parents if there is any signs of fleas in located in the rear end of fleas that help them feel the environment.

Figure
Figure

Figure
FigureMain body structures of the cat flea, as seen through a laboratory magnifying glass. Figure