What are lice?
Lice are tiny, wingless parasitic insects that live on the skin and feed on blood. There are several different types of lice that can affect dogs, humans, and other mammals.
The three main types of lice are:
- Head lice – Pediculus humanus capitis. These lice affect human scalps.
- Body lice – Pediculus humanus corporis. These lice live in human clothing and bedding and feed on the body.
- Pubic lice – Pthirus pubis. These lice live in human pubic hair.
Dogs can become infected with the following types of lice:
- Linognathus setosus – A louse that is specific to dogs.
- Trichodectes canis – A chewing louse that feeds on tissues and debris from the dog’s skin surface.
Lice go through three life stages – egg, nymph, and adult. The female louse lays eggs called nits that hatch into nymphs. The nymphs molt three times before reaching adulthood. The life cycle from egg to adult takes about 2-3 weeks. Lice can only survive 1-2 days off the host.
Lice spread through direct contact with an infected person or animal. They cannot jump or fly, so close head-to-head contact is required for transmission.
Do dogs get lice?
Yes, dogs can get lice. There are three main species of lice that commonly infest dogs:
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Linognathus setosus – A bloodsucking louse that feeds on the dog’s blood. These lice cause skin irritation and can lead to anemia if the infestation is heavy. (Source: https://www.merckvetmanual.com/dog-owners/skin-disorders-of-dogs/lice-of-dogs)
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Trichodectes canis – A biting louse that feeds on skin and secretions. These lice cause intense itching, hair loss, and skin inflammation. They are extremely contagious between dogs. (Source: https://www.akc.org/expert-advice/health/can-dogs-get-lice/)
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Heterodoxus spiniger – A biting louse similar to T. canis. They also cause itching, hair loss, and skin issues in dogs. (Source: https://www.merckvetmanual.com/dog-owners/skin-disorders-of-dogs/lice-of-dogs)
These lice are often found on a dog’s head, neck, tail, and limbs where the hair is thinner. Heavy infestations can spread across the entire body. Lice attach to the base of the hairs to feed. (Source: https://www.akc.org/expert-advice/health/can-dogs-get-lice/)
Do humans get lice?
Yes, humans can get head lice and body lice (CDC). Head lice are tiny wingless insects that live and breed in human hair and feed on blood from the human scalp. They are found most commonly on the scalp, behind the ears, and at the back of the neck. Body lice are similar but are found in clothing and bedding and feed on blood from the body. Humans get head lice most commonly through direct head-to-head contact with an infested person. Less commonly, head lice can be spread through contact with infested items such as clothing, hats, scarves or other personal items (Minnesota Department of Health). Body lice are spread through contaminated clothing or bedding. Overall, lice are spread through close personal contact and are not a sign of poor hygiene or being dirty.
Can humans give dogs lice?
Humans cannot directly transmit head lice to dogs according to this source: https://wagwalking.com/wellness/can-dogs-get-head-lice-from-humans. Human head lice feed specifically on human blood and require the temperature of the human scalp to survive. However, human head lice can briefly survive on dogs and lay eggs according to this source: https://liceclinicsupstateny.com/can-pets-get-lice/. While the eggs usually don’t hatch, there is a small risk of head lice transmission if there is direct head-to-head contact.
Human body lice may be able to live longer on dogs than head lice. Body lice are able to survive away from the human body for longer periods. According to this source, if a human body louse falls onto a dog, it may be able to survive: https://www.licelifterslanc.com/blog/can-we-get-lice-from-or-give-lice-to-our-pets/. However, there is still no evidence that dogs can sustain populations of human lice long-term.
Can dogs give humans lice?
No, dogs can’t transmit their lice directly to humans. According to Can Dogs Get Lice?, dog lice species such as Trichodectes canis are host specific and only feed and reproduce on canine hosts. Humans are not suitable hosts for canine lice species.
Dog lice can’t survive or reproduce on human bodies. As explained by Can Dogs Get Head Lice From Humans?, dog lice require dog blood to complete their life cycle. They are biologically adapted to live on dogs and quickly die if they jump to a human host. There is no evidence that dog lice can establish persistent colonies on humans or cause lice infestations.
In summary, while humans and dogs can have close contact, dog lice cannot be directly transmitted to humans or survive long-term on human bodies. The species barrier prevents dog lice from infecting humans.
Risk factors for lice transmission
There are several risk factors that can increase the chances of lice transmission between humans and dogs:
Close contact between humans and dogs is a major risk factor. Lice spread through direct head-to-head contact, so activities like cuddling, sleeping in the same bed, or playing closely with your dog can provide opportunities for lice to jump hosts (Source: https://www.cdc.gov/parasites/lice/head/index.html).
Dogs with long fur coats are more prone to getting lice infestations. The longer hair provides more places for lice to hide and multiply. Short-haired dogs are at lower risk (Source: https://wagwalking.com/wellness/can-dogs-get-head-lice-from-humans).
Poor hygiene and crowded living conditions can also facilitate the spread of lice between people and pets. Lice thrive in dirty environments, so dogs that are not regularly bathed/groomed or live in overcrowded shelters or homes are more likely to carry lice.
Preventing lice transmission between dogs and humans at home
There are several steps pet owners can take to reduce the risk of lice transmission between dogs and humans sharing a home:
Regular grooming and bathing of dogs can help remove and kill any lice before they can spread. Use a lice killing shampoo on dogs showing signs of infestation. According to the American Kennel Club, bathing dogs at least once a month helps keep their skin and coat healthy and clean.
Keeping dogs out of human beds and bedding reduces possible transfer of lice onto pillows, sheets, etc. Lice can survive for brief periods in bedding and carpets. The CDC recommends washing bedding in hot water regularly if a lice infestation is found.
Treating any lice infections in pets or humans promptly with vet or doctor recommended anti-lice treatments can stop the spread before it becomes an outbreak. Prompt treatment for all family members reduces reinfection.
Maintaining a clean home environment helps limit potential transmission vectors. Vacuuming carpets and furniture regularly, along with washing linens and pet bedding can remove lice before they spread.
Treating lice in dogs
There are several treatment options for getting rid of lice in dogs:
Anti-parasitic medications: Products like fipronil, selamectin, or isoxazolines can be prescribed by your vet to kill lice (Lice in Dogs and Cats – Veterinary Partner – VIN). These are often topical medications applied between the shoulders.
Medicated shampoos: Over-the-counter pyrethrin shampoos can help kill lice on contact during bathing. Make sure to thoroughly lather and leave on for 5-10 minutes before rinsing (Lice).
Nit/egg removal: Carefully combing your dog’s coat with a fine-toothed metal flea comb can help remove nits and eggs. Focus on one section at a time.
Fur trimming: Trimming the fur short may make egg removal easier.
Environmental cleaning: Thoroughly wash all bedding, towels, and fabric items your dog contacts. Vacuum carpets and furniture to remove all traces of lice.
Treatment often needs to be repeated frequently to kill newly hatched lice. Work with your vet to ensure lice are fully eliminated. Be vigilant about combing, cleaning, and re-treating as necessary.
Treating lice in humans
There are a few methods for treating lice infestations in humans, including using anti-lice shampoos, creams and lotions, combing out nits and eggs, and washing clothing and bedding in hot water.
The CDC recommends treating head lice with over-the-counter or prescription medicated shampoos, creams, or lotions that contain pyrethrins or permethrin. These products work by killing live lice [1]. Popular over-the-counter brands contain permethrin or pyrethrins such as Rid, Nix, or A-200. Prescription products such as Natroba (spinosad) and Sklice (ivermectin) are also available. It is important to carefully follow product instructions to fully remove lice.
In addition to medicated shampoos and topical treatments, diligently combing out nits and eggs from the hair using a nit comb helps physically remove lice [2]. Nit combs are special fine-toothed combs designed to remove lice eggs and nits from the hair shaft. This combing should be done in conjunction with topical anti-lice products.
Finally, to prevent reinfestation, all clothing, bed linens and towels should be washed in hot water and dried on the hot cycle after lice treatment. Personal items like brushes, combs and hair ties should also be thoroughly cleaned [1].
Summary
In summary, while lice transmission between dogs and humans is possible, it is quite rare. Lice tend to be species-specific, meaning dog lice usually only infest dogs and human lice usually only infest humans. For lice to jump between species, very close direct contact is required.
There are some preventative steps that can be taken to reduce the chances of lice transmission even further. These include regularly inspecting and grooming your dog, washing bedding frequently, keeping dogs and humans with lice separated, and consulting a vet for appropriate treatment options if lice are found.
The key learnings are that lice transmission across species is uncommon, so there is no need to panic if you find lice on your dog or yourself. But taking sensible precautions can minimize any risk. Overall, while uncomfortable if they occur, lice infestations are treatable in both humans and dogs.