FLEA PREVENTION: Measures for preventing flea infestations

Indoor cleanness: cradles, nests and other places pets prefer

If pets have fleas, wherever they sleep or rest there will be a substantial accumulation of immature stages together with abundant food for the larvae (mainly flea feces) and at an ideal temperature. For this reason sanitation of these places is essential for flea prevention. They have to be cleaned or changed regularly, and stuffing materials, pieces of cloth, rags, etc. should be renewed or washed at high temperature to eliminate or kill whatever eggs, larvae or cocoons they may contain.

The same applies to any other places where pets like to stay: chairs, couches, cushions, beds (including blankets, mattresses, etc.), pillows, as well as whatever indoor or outdoor spots (yard, garden, balcony, stairs, etc.). These are the places where eggs, larvae and cocoons will accumulate, especially if they are covered with whatever thick textile. These places have to be vacuumed and/or steam cleaned frequently (e.g. weekly). Newest research indicates that vacuuming kills the fleas, thus immediate disposal of the dust bags is not necessary. It may be advisable to prevent pets from staying in places that are difficult to clean.

General hygiene and sanitation are always a good idea, but unremoved kitchen garbage or general trash are not a direct source of fleas, although they can certainly feed and/or breed numberless flies and cockroaches. However, such garbage can be an indirect source of fleas by attracting wild rodents (rats, mice) or birds, which are almost always infected with fleas.

Outdoor cleanness: gardens, yards, balconies, etc.

Oranges, the major source of D-limonene, a natural flea insecticide. Picture taken from Wikipedia Commons

Fleas can also develop outdoors, in private and public grounds, especially in regions with warm and humid climate. A few measures can reduce their suitability for flea development:

  • Regular mowing the lawn. If grass becomes tall it will flourish and produce seeds. These seeds attract wild rodents and birds, which are almost always infected with fleas. And such small animals will attract straying dogs, cats, foxes and other hunters, which can carry even more fleas.
  • Remove whatever organic dirt and waste that could also attract wild animals infected with fleas.
  • Keep domestic or wild animals off your property with walls or adequate fencing. Foxes, raccoons, skunks, hedgehogs, etc. can carry a lot of fleas.

Prefer hard flooring to carpets and rugs

There are structural measures that make the environment more or less appropriate for the development of flea eggs, larvae and cocoons, i.e. that are favorable or not for the establishment of a flea population:

  • Carpets and rugs (of natural or synthetic fibers) as well as dry sandy soils are ideal flea breeding environments. An option to reduce flea breeding can be to deploy carpets and rugs in winter, and to remove them in spring and summer.
  • Hard and plastic flooring (stone, tiles, wooden parquet, etc.) are much less appropriate for flea breading. However, gaps or cracks (e.g. between parquet slates) filled with dirt can support flea development.
  • Textile upholstery (natural or synthetic) are much more supportive of flea development than leather or plastic, which are impenetrable for the larvae: they will remain outside and dry out or starve.

Keep pets away from other animals that can have fleas

During the flea season it is especially important to prevent pets from getting in close contact with other pets that are likely to carry fleas, especially stray pets. 

There are many other animals that may have fleas and can transmit them to pets: squirrels, rats, mice, rabbits, guinea pigs, foxes, all kinds of birds, but also sheep, goats, cattle, horses, etc. If contact or close vicinity is not always avoidable, they should be kept off their habitats or stables.


MECHANICAL CONTROL of fleas

As a general rule, mechanical contorl of fleas can reduce flea numbers but are insufficient to solve a well established flea problem.

  • Flea combs, although cumbersome, can reduce the number of fleas on a pet by up to 75%. Obviously they don't eliminate any of the immature fleas in the environment.
  • Sticky traps and light traps can catch a lot of newly emerged adult fleas that wait for a host in carpets, rugs, upholstery, etc. This is not bad, because these fleas are precisely those more likely to jump onto the pet's owner. However, they will not catch fleas already on the pets, and will not eliminate the flea population.
  • Vacuuming as thorough as possible removes a lot of eggs, larvae, cocoons and adult fleas from carpets and rugs. It is especially recommended to do it shortly after treatment of facilities with insecticides because it stimulates the hatching of preemerged adults. Don't forget to eliminate the dust bag: larvae can continue development and cocoons can release adult fleas inside the bag!
  • Steam cleaning carpets, rugs and unpholstery also kills adult fleas and larvae.
  • Washing all cloth in pets' nests and craddles with detergents will also eliminate many immature fleas they may contain.
  • It has been proven that ultrasonic devices are ineffective for repelling fleas or for reducing flea infestations. They may even annoy pets because dogs and cats do hear certain ultrasounds that humans don't.

NATURAL INSECTICIDES and REPELLENTS

Unfortunately natural insecticides (e.g. essential oils from certain plants) can kill or repel some fleas, but they will not be sufficient to significantly reduce an established flea population.

There are currently no commercial repellents capable of keeping fleas away from pets, humans or animals for more than a few hours, if at all. Most natural or synthetic repellents target mosquitoes and to some extent certain fly species, but are rather weak against fleas.

Several studies have shown that sulfur, beer yeast and B-complex vitamins have no repellent effect on pet fleas.

Click here to learn more about natural insecticides (azadirachtin, d-limonene, geraniol, linalool, pyrethrins, etc.) in this site.


MEDICINAL PLANTS used in home-made traditional remedies against fleas

There are many home-made remedies against fleas, most of them based on traditional recipes using locally available herbs or other natural products. They are the result of centuries of efforts for finding relief against fleas when modern insecticides were not available. 

The bottom line is that no such remedies are as effective as modern synthetic pesticides. They may bring partial relief for a few hours, maybe a few days, but certainly not week or month-long protection. They are often unreliable, and are completely insufficient to control flea populations established in a household.

It is good to know that in most countries such "natural products" (e.g. plant extracts) are submitted to less stringent regulations than veterinary parasiticides. This means that they don't need to proof their efficacy against parasites, or their safety for the pets, users and the environment through such strict and thorough investigations as the products containing synthetic parasiticides. Many regulatory authorities seem to simply assume that being natural they are "safe enough", or at least not harmful, and that users will find out themselves whether they are effective or not... Consequently the cost and the know-how to develop and market such "natural products" is substantially lower than for veterinary medicines containing synthetic parasiticides. This low cost explains their proliferation. It is not possible to deal with such products here in detail. However, nothing speaks against trying them. If they work, fine. If they don't, you will never know whether the recipe is useless or whether you did something wrong. But it doesn't matter: just try another one.

BUT: when dealing with plant remedies, it is good to know that the active components in herbs are also chemicals, i.e. specific molecules that have a biological effect, in this case an insecticidal effect. They have been naturally synthesized inside the plants. But this says nothing about the safety of such chemicals. It is wrong and dangerous to believe that something is safe because it is natural! The most potent poisons known are often of plant or animal origin. And by the way, many such "natural products" that are used in numberless so-called "natural" or "bio" products are also industrially manufactured or synthesized.

In the following a selection of medicinal plants with some reported efficacy against fleas is listed:

  • Artemisia absinthium (Absinthium, Wormwood, Green Ginger, etc.) is an herbaceous plant native to temperate Europe, Asia and Northern Africa. The whole plant contains eucalyptol and thujone (which is rather toxic). A water infusion seems to have an effect against fleas. Anthelmintic efficacy has been reported against gastrointestinal roundworms in sheep. Used in excess can be harmful because some animals don't tolerate it.
  • Chrysanthemum cinerariaefolium (Daisies, Mums, Chrysants, Xants) is a perennial flowering plant native to Asia and Southeast Europe, nowadays cultivated worldwide. They are vastly used as ornamentals and for the production of natural pyrethrins, the most widely used natural insecticides.
  • Cymbopogon nardus and Cymbopogon winterianus (Barbed Wire Grass, Citronella Grass, Lemon Grass, etc.) are perennial grasses native to Asia, nowadays found worldwide in regions with tropical and temperate climate. The oil contains citronellal, geraniol, D-limonene, camphene, etc. The oil or single chemicals are widely used as insect repellents in numerous OTC products (shampoos, sprays, lotions, dusts, etc.) for pets.
  • Melia azedarach (Chinaberry Tree, Bead-tree, etc) is a deciduous tree native to Southeast Asia and North Australia. Leaves have been used as natural insecticide to protect stored food from insects. A spoon of dried grinded seeds mixed with laundry soap in water (about 1 gallon) seems to repel fleas and other insects when sprinkled over lawns, shrubs, etc. Ethanolic extracts of the fruits showed efficacy against tapeworms (Taenia solium) in laboratory studies. The fruits are toxic to humans.
  • Pimenta dioica (Jamaica Pepper, Myrtle Pepper, Newspice, Pimienta, etc.) is a perennial tree native to Central America and the Caribbean now grown in many tropical and subtropical regions. The fruits contain eugenol and caryophyllene, both with insecticidal activity against fleasflies and mites.
  • Ricinus communis (Castor Bean Plant) is a flowering perennial plant native to East and Northeast Africa now found worldwide in tropical regions. Dried and grinded leaves and stems are used as a dust for direct topical application on sheep, goats, poultry and pets against fleasflies and mites. The seeds contain ricin, which is highly toxic for humans and animals.
  • Rosmarinus officinalis (Rosemary) is a perennial herb native to the Mediterranean now cultivated worldwide. The essential oil contains several chemicals with insecticidal properties, e.g. camphor, eucalyptol and pinenes. Grinded leaves are said to repel fleas and ticks.
  • Tanacetum vulgare (Tansy, Bitter-buttons, Parsley Fern) is a flowering plant native to the Northern Hemisphere. The oil contains tannins and thujone. Was used in the past as traditional anthelmintic and against human fleas and lice. However, if ingested a few grams are already toxic for humans and animals. Feed to sheep it showed efficacy against certain gastrointestinal roundworms (Nematodirus spp).

Click here if you want to known more about medicinal plants traditionally used against veterinary parasites.


FLEA VACCINES for dogs and cats?

It has become quite usual among pet owners to talk about "flea vaccines". Most people mean those products that are administered to pets at monthly or longer intervals to keep them free of fleas. These products are not true vaccines but mostly spot-ons (also called pipettes, drops-ons, squeeze-ons, etc.), tablets, pills, chewables or or injections that provide such a protection. More about such products is explained in the article in this site on chemical control.

Such products are not vaccines but classic chemical pesticides. Vaccines contain antigens of specific pathogen organisms (viruses, bacteria, etc.) that activate the immune system of the vaccinated animal or person to produce antibodies against the pathogen organism, i.e., vaccines stimulate the own defenses of the vaccinated organisms against pathogens. A few vaccines contain specific antibodies against specific pathogens, instead of antigens. What current flea products do is simply to kill or to sterilize fleas, but through simple chemical "poisoning", not through natural antibodies, neither produced by the pet's own immune system, nor administered with a vaccine.

Summarizing, there are no such true vaccines against fleas, neither for pets, nor for livestock or humans. A lot of research has been conducted on true flea vaccines, but so far without success. And it is unlikely that a real break-through may happen in the near future.

Click here to learn more about vaccines against veterinary parasites.


BIOLOGICAL CONTROL of fleas?

Biological control of fleas has been poorly investigated. In a few countries a product is available for the biological control of fleas outdoors using entomopathogenic roundworms. It can significantly reduce flea populations in lawns, gardens, etc. However, it is not effective against adult fleas on pets or indoorsagainst immature stages, which usually represent >95% of the flea problem.

Click here to learn more about biological control.


  • Click here to view the article on CHEMICAL CONTROL of fleas in dogs and cats (spot-ons, collars, pills & chewables, injectables, shampoos, soaps, sprays, baths, powders, etc).
  • Click here to learn the basics of flea biology in order to have a better chance to get rid of them. Knowing how fleas make their living (where they live, how they reproduce, how they behave, etc.) will help you to choose the right flea control measures among the many options available. 

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