Flea-Borne Diseases in Dogs

Flea-Borne Diseases in Dogs - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

What are Flea-Borne Diseases?

Fleas are flightless insects, which often parasitize animals such as rodents, birds, wild mammals and companion animals. As a result of their ability to infect a vast variety of species fleas have been known to be carriers of multiple pathogens and diseases. These pathogens may be bacterium such as Rickettsia and Bartonella, or other parasites such as tapeworms.

Often, most flea-borne diseases result in common symptoms such as anemia, scratching and alopecia. However, when left untreated, symptoms may increase in severity resulting in muscle wastage, fever, and pneumonia as a result of secondary infection, and chronic anemia that may lead to shock and eventually death.

A flea-borne disease refers to the diseases and pathogens carried by fleas (vectors) that are transmitted to our companion animals.

Symptoms of Flea-Borne Diseases in Dogs

Flea Allergy Dermatitis

  • Alopecia (hair loss)
  • Skin pain
  • Skin cracking
  • Hyperpigmentation of skin
  • Intensive scratching


  • Progressive weight loss
  • Anemia¬†
  • Colic (abdominal pain)
  • Vomiting¬†
  • Parasites visible upon passing stool


  • Fever¬†
  • Nose bleeds
  • Weight loss
  • Anemia¬†
  • Inflammation of the endocardium¬†


  • Flea allergy dermatitis (also known as FAD)
  • Canine tapeworms
  • Bartonella henselae (also known as cat scratch fever)

Causes of Flea-Borne Diseases in Dogs

Flea borne diseases may be caused by various factors such as:

  • Allowing the dog to come into contact with wild animals (rats, mice or birds)
  • Lack of regular flea treatments

Flea Allergy Dermatitis

  • The flea's antigenic salivary protein entering the skin subcutaneously; this is because the saliva of fleas contains chemical compounds such as histamine and amino acids that result in hypersensitivity¬†
  • Breed genetic predisposition includes Terriers, Spaniels and Chow Chows


  • Caused as a result of the dog consuming the larvae of fleas
  • This may either be through self-grooming or through consumption of recently deceased wild animals (particularly hunting or farm dogs)


  • Caused by a gram-negative bacteria known as Bartonella henselae that is carried by fleas and other infected hosts (infected dogs or cats)
  • This will often spread as a result of blood-to-blood contact

Diagnosis of Flea-Borne Diseases in Dogs

Flea Allergy Dermatitis 

Veterinarians may make their diagnosis of dermatitis simply through a visual examination of your pet. This will include examining for fleas, identifying areas in which hair growth has diminished and inflammation around cracked skin. Veterinarians may also conduct an intradermal test that involves using particular strains of flea saliva in order to test the your dog’s hypersensitivity to a specific strain. 


Veterinarians may request that owners collect their pet's stool in order to perform a fecal flotation test and microscopic exam of feces. This reveals the estimated number of eggs and larvae present in the animal’s intestine. A distance exam and history of your canine’s health may be requested as well. Questions asked by the veterinarian may include:

  • History of regular worming and/or flea treatment
  • Evidence of scooting


As Bartonella is a bacteria, veterinarians may perform a complete blood chemistry and urinalysis on the infected dog. This would be important in determining white and red blood cell count. An indication of elevated white blood cells may suggest a bacterial infection. 

Veterinarians may look for clinical signs such bruising or bleeding as a result of decreased platelets production. In situations where blood cultures may fail, then assays will be performed in order to detect the DNA of the bacteria in the blood.

Treatment of Flea-Borne Diseases in Dogs

Flea Allergy Dermatitis 

Flea allergy dermatitis may be treated by the use of regular topical flea treatments on your dog. Veterinarians may treat the infected dog with insect growth regulators that significantly reduce the growth rate and development of the larvae. Should bacterial infection occur as a result of FAD then your dog may be prescribed a course of antibiotics in order to reduce any inflammation that may be present. Owners may also be required to cleanse their household entirely by:

  • Bathing their dog with medicated flea shampoo
  • Vacuuming carpeted areas that may be potential reservoirs for flea larvae or eggs
  • Disposing of pet beds and/or any fabric material the dog may have been In contact with
  • Spraying carpets and baseboards with residual flea products that may terminate flea eggs and larvae


Treatment of tapeworms is done through regular deworming every 3 to 4 months as well as maintaining regular flea and tick management. The method of treatment is through anthelmintics of a varied combination. In most veterinary practices, you may receive tablets that have drugs such as pyrantel and praziquantel. 


As Bartonella is a bacteria your veterinarian may recommend a course of intensive antibiotics depending on the severity of clinical signs. General protocol suggests a dose administered twice daily for approximately four to six weeks. These may include amoxicillin in conjunction with fluoroquinolones.

Antibiotics for the treatment of Bartonella are extensive and will result in the death of essential gastrointestinal bacteria as well. Thus, veterinarians may provide owners with probiotics that will maintain gut bacteria and prevent the decrease in the immune health of the affected dog.

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Recovery of Flea-Borne Diseases in Dogs

Flea-borne diseases may vary from viral and bacterial infections to allergic reactions. When a dog develops flea allergy dermatitis, veterinarians will suggest treating your pet with topical treatments on a regular basis, particularly during summer and fall months.

When there are bacterial infections, a course of antibiotics may be prescribed along with probiotics in order to maintain your dog’s gastrointestinal health. Veterinarians may also suggest making changes in a household infested by fleas. This may require:

  • Owners bathing pets in medicated shampoo
  • Regular deworming and usage of spot on flea solutions
  • Restricting your dog from interacting with wild animals
  • Vacuuming the household on a regular basis
  • Disposing of pet beds that may be hosting flea eggs and larvae
  • Routine check-ups

It is important to remember that eradicating fleas from the household and your pets may take many months, as eggs may lay dormant when the environment is not favorable. Thus, following a veterinarian's instructions and regular visits to your vet will aid in the management and recovery of your pet.

Flea-Borne Diseases Questions and Advice from Veterinary Professionals


chihuahua/ jack Russell mix



Eleven Years


8 found this helpful


8 found this helpful

My pet has the following symptoms:
Paracite Type Bugs Then Oozes Puss Sores Like Holes , Looks Like Blood Under Nails Of Paws And I Think I May Have The Bug Thing But My Other Two Dogs No Signs
With covid 19 hard to go see regular vet just paid a 400 bill on one pet. So I hope u can answer? She has had off and on Ill catch them after they must pop. But recently I thought were fleas now not thinking so other two dogs no signs. But maybe a coincidence but I have similar sores but no puss filled they itch and leave a whole been to doctor they say nothing there but my psoriasis. I was trying to take the bug thing I thought were there she put under the scope said only skin cells I don't know . I'm maybe pulling at straws? Its at nightmare stage due to I wash her w/dawn I see them surface

Sept. 28, 2020

Answered by Dr. Michele K. DVM

8 Recommendations

Thank you for your question. Without seeing these sores and skin lesions, it is very difficult for me to comment, but Sarcoptes is one parasite that can affect people and make everyone itchy. It does tend to be quite contagious, and is generally easy to treat if your dogs are on Nexgard or Bravecto. Other than that, I can't think of any parasites that would cause the signs that you are describing... I hope that you and your veterinarian can get to the bottom of it!

Oct. 5, 2020

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