Is it possible to spread lice between humans and pets?


The lice They are one of the external parasites that most often affect cats. They usually invade stray cats or home cats with access to the outside, especially if they are still young, elderly or sick.

Although they are not as contagious as fleas and ticks, lice cause the same discomfort in your feline friend, such as itching and hair loss, in addition to transmuting certain diseases. That's why in ExpertAnimal we have prepared for you this article about lice in cats, symptoms and treatment.

How do lice affect cats?

The louse is a helicopter insect of few millimeters that has no wings and is not able to jump, but that lives as a parasiteof some mammals. There are about 3000 different types of flippater (Phthiraptera) and each one is quite selective with the animals that become its hosts, so they usually only attack certain specific species.

The louse that attacks cats is the Felicola subrostratus, it is not transmitted to other animals or to the human being, although yes to other feline species. It mostly affects young cats that have not yet developed good defenses, to elderly felines who have stopped cleaning themselves and to all those who, whether due to poor diet or because of disease, are weak or immunocompromised. Long fur is also decisive when it comes to suffering from these parasites.

They are usually more common in cold times of the year and they are spread among cats that spend a lot of time together, because the louse neither flies, nor jumps, nor hides among the grass in search of a host. All his life is spent in the body of the animal, far from which he dies quickly, in just 1 or 2 days. Cat lice are not spread to humans.

Symptoms of lice in cats

The presence of lice in your cat's fur is quite clear. First, easily They are visible to the naked eye, because of their dark color and because they walk through the hair. Even in long-haired cats, you can see them if you remove the upper layers a little with your fingers, although the most obvious symptoms are eggs, whitish, that adhere very easily. You can try to pass an anti-lice brush to make sure they are there.

Other characteristic symptoms of the presence of lice in the cat are:

  • Hair looks matted and dirty.
  • The cigar or itching is quite intense, so it is likely that the cat scratches frequently or tries to bite the areas that most bother you, even causing self-mutilation.
  • As a result of scratching and biting we can see wounds that can become infected or thickening of the skin.

Treatment of lice in the cat

In the market there are multiple options to eliminate the lice that affect your cat, although none is specially formulated for these parasites, since they are the least common.

In any case, if your cat has a lice infestation, we will start by performing a bath with an antiparasitic shampoo. Then we will use an anti-lice comb to remove the insects that still remain in the dermis, as well as the eggs. Once removed, you must drown the annoying parasites in some alcohol or hot water. Be sure to work the fur completely.

If you have never bathed your cat, you should assume that bathing an adult cat for the first time can be very complicated, if not practically impossible. In these cases it may be useful to offer a antiparasitic tablet that also acts for the elimination of external parasites.

Finally, and if the bath is impossible or offers a pill (and although we do not recommend the use of drugs whenever possible), we can consult with our veterinarian the option to calm our cat with medication. Of course, we will totally reject the use of acepromazine.

Two days after the application of any antiparasitic product we must apply a pipette, necklace or spray to end the parasites that could remain alive in the feline nustro coat and to prevent the appearance of new ones.

If there are other pets at home, a preventive treatment will be necessary to avoid infestation. The lice do not survive outside the animal, but it would be advisable to clean the beds, bedspreads, toys and other objects of your cat. Use hot water for it.

Lice Prevention

It is very important to prevent the appearance of parasites in cats that have outside access or those who they live with other pets They do have access outside, as is the case with cats that share a home with dogs.

Ideally in these cases, apply deworming products periodically, such as pipettes, necklaces or sprays. To know how often to deworm your cat, consult your veterinarian and follow product instructions rigorously.

This article is purely informative, at we have no power to prescribe veterinary treatments or make any kind of diagnosis. We invite you to take your pet to the veterinarian in case he presents any type of condition or discomfort.

If you want to read more articles similar to Lice in cats - Symptoms and treatment, we recommend that you enter our Deworming section.

We tell you why there is no spread of lice between humans and pets

Lice are insects with more than 3,000 varieties, each with a specific name. They act as parasites of the animals in which they live. In other words, they need a specific guest to survive. For this reason, lice that affect pets cannot be spread to humans and vice versa.

So, the pediculus humanus capitis, those annoying tenants who sometimes move to our heads are those of humans. They cannot survive in a dog or a cat. The same goes for lice that pets may have. People do not serve their ends.

So, keep in mind that lice removal products that attack humans should not be used on pets. And the treatment prescribed by the veterinarian to eliminate these insects from your dog or your cat should never be used on you or your children.

Head lice that affect pets are not spread to humans. In the same way, those who dwell in dogs and cats cannot survive in our heads.

Characteristics of the louse that lives in the head of humans

Head lice that live on people's heads do not measure more than 3 millimeters and are ovoid. Depending on the amount of human blood in your body, its color may vary from yellow to brown. Their eggs are called nits and reach between 0.3 and 0.8 millimeters.

Contrary to popular belief, they don't jump or fly, since they don't have wings. But, as they travel at a speed of between 6 and 30 centimeters per minute, they can easily pass between the heads that are in contact. And while they do not pose a threat to health, they are a real nuisance.

The typical itching that usually occurs in the scalp is due to the pecks that give us to feed on our blood. Although they cannot survive more than 48 hours away from a human head, they do survive hair washes and baths in a sink.

What should we do if there is a plague at school?

The first thing to do is inspect the child's head to rule out all doubts. In case you have lice, you should immediately start an appropriate treatment and continue with the process to follow in case of infestation. In addition, we must check that other family members have not been infected as well.

In case there is no contagion but our child is immersed in an environment where there are lice, we must avoid direct head-to-head contact, do not share utensils or hair objects between friends and family, wear collected hair, use a repellent cologne with a childish smell so that the child does not feel uncomfortable and make routine scalp checks.

Cats, dogs and lice

It is unlikely that a healthy pet has lice. Generally, they appear in animals with poor feeding and at early or advanced ages. However, if you suspect that any of your four-legged friends is affected by this type of ectoparasite, do not despair. They are easier to remove than fleas or ticks.

The species of lice that most frequently attack our four-legged friends are:

Trichodectes canis

  • Reach dogs from all continents
  • Its length varies between 1.5 and 2 millimeters
  • It is mostly located on the head, necks, ears and torso of animals

These 3 types of lice can transmit, for example, Dipylidium caninum, a parasitic wormfish parasite of canids and felids.

Check daily and act quickly

Keep in mind that so that both people and animals do not end up invaded by these unwanted insects, the important thing is to stay alert and check the head of our children and the fur of our pets and act quickly if any lice are discovered.

Consult the doctor or veterinarian, as appropriate, for advice on the best way to eliminate them without affecting the health of humans or pets.

Does cutting your hair help fight the infestation?

No. It would only help to shave your head. Lice can feed and live equally in short hair.

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By Zulema Usach - [email protected]

Applying veterinary drugs to combat pediculosis constitutes a potential risk to people's health. Even its short and long term consequences are not even scientifically evaluated. Far from being disseminated at random, the warning came after a researcher at the National University of Cuyo (UNCuyo) found that this resource is used in the population more than is believed.

To verify their suspicions, the veterinarian and teacher of the Pharmacology area of ​​the Faculty of Medical Sciences, Manuel Guevara conducted a survey among more than 46 veterinarians from Mendoza and San Juan, in which he asked if at any time they had received requests from of its customers to buy chemical compounds - aimed at fighting ticks and fleas on animals - which were then applied to children and adults with lice. The answer, in 97% of cases, was yes.

Among the most questioned and most requested drugs, are fipronil (a broad-spectrum insecticide that has been commercialized since 1994 for the control of fleas and ticks in dogs and cats), which comes in pipettes, and propoxur, the drug which contain veterinary sprays. Both are over-the-counter, so their use is not regulated.

The truth is that these insecticides are not approved to be intended for human beings. However, it has happened that due to ignorance many moms have used them to try to eradicate head lice from their children. The indication in the veterinary rooms, detailed the professional, is done informally and without any control.

In addition to the widespread "word of mouth" recommendation, Guevara said there are veterinarians, doctors and health personnel who advise its use. "Even the teachers ask them, who constantly fight with the problem of pediculosis," explained the professional and cited that with the aim of raising awareness in the population, their conclusions were disseminated in two specialized scientific dissemination journals and within the framework of A conference for veterinary professionals, a few days ago.

"Doctors and veterinarians have an obligation to ensure public health and we must be aware of the consequences of improper use of drugs not approved for use in humans," said the UNCuyo specialist.

Guevara insisted that the health risks or damages that these chemicals can generate in humans are not known. "It is necessary to inform parents to prevent them from using inappropriate products. It is not known if someone who did a treatment that is actually intended for animals can within a few years generate a disease, such as cancer," the researcher warned. In animals, in fact, these compounds must be administered with a lot of responsibility, since they are not harmless, enter through the skin and are deposited for at least two months in the body.

To reinforce his warning, the professional cited that what is proven is that fipronil increases the level of thyroid hormones. On the other hand, he added, that in Africa, where propoxur is used to fumigate, it was seen that pregnant women who had that blood toxic had children with inferior neurological development.

One of the reasons why we tend to resort to unconventional methods to combat pediculosis is the resistance that parasites generate to pediculicides. In fact, Guevara explained that each product complies with a constant research and evaluation process, so the doses are updated according to the level of resistance generated by the parasites.

"It is estimated that 1% will be resistant and survive the treatment. That is why, precisely, the drugs are being renewed," said the veterinarian and added that this also happens with the chemicals used in animals. Therefore, he recommended that the ideal comb to combat the infestation is the fine comb because it drags both the lice and the nits (eggs) that invade the scalp and the root of the hair.

Jennifer Ibarra, a veterinarian, explained that the sale of zootherapists is actually regulated. The problem, he said, is that it can happen that a person goes to the veterinarian to buy the product without the veterinarian in charge has the possibility to verify the destination that the client will give him.

In businesses that sell pet products it is possible to get these poisons, without the supervision of a professional. Ibarra aimed at strengthening controls and appealed to the responsibility of professionals, merchants and parents in this regard. He said that the intervention of organizations such as Senasa (National Service of Agrifood Health and Quality) is necessary, so that inspections are carried out.

Lice in dogs

As we mentioned initially, although dogs may have lice cannot transmit them to humans, and the same happens in reverse, since the species that affect each organism are different. Let's see below what are the lice that can affect your dog:

  • Heterodoxus spiniger: Measures approximately 2.5 cm. long and although it does not usually occur in Europe, it is a louse that can transmit other parasites such as Dipylidum caninum or Dipetalonema reconditum.
  • Linognathus setosus: It feeds on the dog's blood, measures approximately 1.5 to 2.5 mm. long It mainly affects the head, neck and chest area.
  • Trichodectes canis: This louse measures 1.5 to 2 mm. long but can also transmit Dipylidum caninum, mainly infests the head, neck, ears and torso.

Of these 3 species, two of them can transmit helminths or intestinal worms and the longer they stay in your dog, the greater the chances that this transmission will take place.

How lice are spread in cats

Is it possible for a cat to have lice? The answer is yes. And to the question: is it possible that the contagion is given from humans to cats or vice versa? The answer is no.

More than 3,000 varieties of lice are known, each with a specific name and specific ways of acting. Lice are small insects that live between skin and hair. These parasites in cats, as well as other species, are characterized by claws that cling to the fur and the most common species in these felines are Felicola subrostratus lice. Being a pest, females shed their eggs, commonly known as nits, in the hair, so the plague can quickly spread through the hair and skin causing itching.

Although humans can also become infected with lice, there are different types of parasites specific to each animal species. Thus, we understand that contagion between people and cats is impossible, although it is possible that your cat has been infected with lice, either by being in contact with another infested feline or with surrounding objects that are also infested.

On the other hand, you should know that, although it does not represent a serious threat to health, it is a very contagious pest, therefore if you have more than one feline, it isolates and treats the affected person to avoid contagion to others. In the case of cats, the appearance of lice usually indicates poor cat health, so it is very difficult for a healthy cat to be infested with lice, unless it is in the middle of a very plagued area.

What causes body lice infestations?

The body louse is larger than other types of lice. They lay their eggs and leave residue on the skin and clothing. Lice can crawl, but they can't fly, jump or jump.

Infestations occur worldwide and They spread through close contact between people or through used sheets, towels and bedding. In general, body lice infestations are limited to people living in unhygienic conditions or overcrowded and have no access to clean clothes.


Lice and pets

(Photo via: cesarsway)

It is very unlikely that a healthy pet has lice. They usually appear in poorly fed animals, especially in puppies and the elderly. Anyway, If you suspect that your pet may have lice, don't panic! Actually, lice they are not excessively difficult to eliminate, much easier than other parasites, such as fleas or ticks.

Let's see what are the main species of lice that affect our four-legged friends:

  • Felicola subrostratus

It affects cats and is present throughout the world. It is a chewing insect with a size between 1.2 and 1.3 mm. As usual, usually proliferates more frequently in elderly and abandoned cats, especially in those with long hair.

  • Heterodoxus spiniger

It affects dogs and It is found on all continents except Europe, although it is originally from Australia, where it went from the dingoes to the settlers' dogs. It is a chewing insect with a size of up to 5 mm.

  • Trichodectes canis

It affects dogs around the world, in which it is usually located on the head, neck, ears and torso. It can measure between 1.5 and 2 mm.

These 3 types of lice can transmit, for example, the so-called Dipylidium caninum, a parasitic wormfish parasite of canids and felids.

Natural, vegetable or homemade remedies to eliminate or prevent lice in dogs and cats

The truth is that there aren't many really effective natural remedies - say blunt - to control the lice of dogs and cats, especially if it is a question of controlling a strong infestation. They can reduce the population somewhat, but they are not always very reliable and the effect will not be very lasting.

On the Internet there are numerous sites that propose various home remedies, but almost none is supported by serious studies. However, trying them costs little and you hardly run any risks. Most are based on pyrethrins, essential oils or extracts of certain plants (citronella, lavender, mamey, tangerine, masambey, neem, oregano, pennyroyal, grapefruit, rosemary, melissa, etc.). Garlic is especially famous against lice, mixed with pet food (if you accept it ...).

Some of these extracts or vegetable essential oils are also part of "biological" or "natural" commercial products in the form of pipettes, shampoos, lotions, sprays, etc. Its effectiveness is usually markedly inferior to that of commercial synthetic chemical antiparasitics, both the curative and the preventive effect (duration of protection). Apart from having an intrinsic efficacy less than that of synthetic chemical antiparasitic agents, many of these products hardly resist water and washing, and sunlight (UV rays) breaks them down much more easily than synthetic antiparasitic agents.

It should be noted that, in many countries, products classified as "natural" (eg plant extracts) are subject to much less stringent regulations to receive the marketing permit than synthetic chemical antiparasitics, both in terms of efficacy against parasites, such as safety for pets. Because they are natural, they are not supposed to be dangerous ... And with respect to effectiveness, the user can decide whether the product is effective or not ... It is clear that the development costs of these products are substantially lower than those of synthetic chemical antiparasitic agents, what makes these products proliferate enormously in some places. It is impossible to deal with them here in detail.

You may be interested in the article on this site about medicinal plants ticks and insecticides (link).

Products for chemical control of lice in dogs and cats

For the chemical control of lice in dogs and cats practically the same products are used as against fleas. It is mostly about

The endectocides injectable (eg ivermectin) (link) are also effective against most lice. But they are not usually authorized for cats, and in dogs you have to be careful, as some breeds do not tolerate ivermectin or other endectocides. For now there is no antiparasitic oral effective against lice.

Because they are quite contagious parasites, to cure infestations you have to treat all the pets that live in the same house.

For the pet owner and for practical purposes, it matters little to know what species of lice the pet has caught, and it is very difficult for him to diagnose the species. It is the task of the veterinarian to establish the diagnosis and select the most appropriate product.

Not all flea or tick products are automatically effective against lice, and vice versa. Read the label carefully of the product.

Shampoos, soaps, baths, sprays, etc. against lice

The general characteristic of these products is that the duration of protection against infestation by fleas and lice is markedly shorter than that of pipettes and collars. Depending on the product, no more than 2-4 days of protection should be expected, sometimes even less. This may be enough if you only want to clean (that is, cure) the pet of a flea or lice that it has already caught. For lice infestations it is often enough.

Many of these products contain synthetic chemical antiparasitic of the classes of pyrethroids (cypermethrin, deltamethrin, permethrin, etc.), carbamates (carbaryl, propoxur, etc.) and organophosphorus (chlorfenvinfos, chlorpyrifos, cumaphos, diazinon, dichlorvos, trichlorfon, etc.) or well active substances of natural origin such as pyrethrins, d-limonene, linalool, and other vegetable essential oils. Like spot-ons and necklaces, they almost always also have an effect against other parasites than lice: fleas, mites, ticks, depending on the composition.

Some are ready for use (shampoos, soaps, lotions), others must be diluted in water before use (liquid concentrates or bath powders).

From a safety point of view, special care must be taken with concentrated products that must be diluted in water before use, especially those containing organophosphates. An incorrect dilution can cause toxic overdose for the pet or underdosing and ineffectiveness against lice.

You may be interested in the article on this site with more information Over the shampoos, soaps, etc. (link)