Parasitic diseases in dogs: what are they?

The dog can at any age suffer from a parasitic disease transmitted by a mosquito, a tick, or a sandfly. The consequences can be very serious for the animal, especially since some of these diseases are fatal. The protection of the dog is therefore essential. Let’s put the spotlight on common parasitic diseases in canines and that could be avoided with prevention.

Canine leishmaniasis

Chronic, this parasitic disease is serious. It is the sandfly, a stinging insect that transmits leishmaniasis when it carries the responsible parasite. Dissemination of the latter in cells is quite rapid. The organs are then affected. Older and / or fragile dogs are more likely to get sick once the parasite hits the immune system.

The symptoms that should alert are:

  • Ulcerative skin lesions,
  • Crusts,
  • Dander,
  • Local hair loss,
  • Nasal bleeding
  • Conjunctivitis,
  • A deterioration of the general condition.

This parasitic disease is deadly medium term.


Following the ingestion of certain gastropods such as snails and slugs, this parasitic disease affects the dog’s lungs and heart because the larvae reach these organs through the pulmonary arteries after passing through the intestinal wall. Note that the fox can also suffer from this disease.

Gastropods are intermediate hosts harboring the nematode Angiostrongylus vasorum. When the dog eats an infected mollusc, it becomes a definitive host. The parasite passes into the adult stage in the dog’s body and this is also where it reproduces.

The main symptoms of angiostongylosis are:

  • Loss of appetite
  • A reduction,
  • Blood clotting disorders,
  • Heart muscle dysfunction,
  • Pulmonary hypertension,
  • Pneumonia responsible for breathing difficulties and a persistent cough …

Consultation is required without delay.

Borreliosis or Lyme disease

Transmitted to the dog by a tick, Lyme disease can go completely unnoticed for a while and eventually leads to very serious health problems. The teacher may not suspect borreliosis in particular because its first manifestations are common to many pathologies. The dog presents for example the following symptoms:

  • A localized redness on the skin, at the site of the tick bite,
  • A state of weakness,
  • Anorexia,
  • Swelling of the lymph nodes
  • An increase in body temperature,
  • Inflammation in the joints,
  • Lameness,
  • Joint pain.

These are ticks infected with bacterium Borrelia burgdorferi family owned spirochetes which therefore transmit borreliosis to dogs.

Piroplasmosis or babesiosis

In France, this parasitic disease is extremely frequent within the dog population. South Brittany, Île de France, Center, East, Southwestern departments are among the most affected areas. It’s a serious illness whose manager is a piroplasm transmitted by the saliva of ticks following: Rhipicephalus sanguineus and Dermacentor reticulatus.

The incubation period is of the order of one to three weeks during which the parasite enters the red blood cells. This is where it reproduces. As a result, the number of red blood cells increases considerably. Symptoms of piroplasmosis are usually:

  • High fever,
  • Unusually dark brown urine,
  • Great fatigue,
  • Vomitings,
  • Diarrhea,
  • Anemia …

The explosion in the number of red blood cells causes damage to the spleen, kidneys, liver and other organs.


The disease is transmitted by a mosquito infested by a nematode, Dirofilaria immitis, whose larvae migrate very quickly to the dog’s heart and then the pulmonary arteries are colonized. The victim presents different symptoms including:

  • Anorexia,
  • Cough
  • Breathing difficulties during an effort,
  • Weight loss,
  • A significant weakening,
  • Jaundice (jaundice),
  • Syncope,
  • Ischemic myopathy,
  • A locomotor deficit,
  • A coma …

An increase in urea and creatinine levels is to be feared due to kidney damage and heart failure. This parasitic disease causes the death of the dog in the short term if the animal is not taken care of as quickly as possible.


Ehrlichiosis is one of the parasitic diseases transmitted to dogs by a tick infected with the bacteria Ehrlichia canis which then contaminates the blood of his victim. It is in the Mediterranean Basin that dogs are particularly exposed to this risk. Difficult to diagnose, ehrlichiosis involves different phases, the acute phase, the latency phase and finally the chronic phase, this one not appearing until a few months to several years after the tick bite. Symptoms of the disease vary over time. The dog may exhibit the following signs:

  • Fever,
  • A state of depression,
  • Vomitings,
  • Joint pain,
  • An increase in the size of the lymph nodes,
  • Rapid weight loss,
  • Blood in the urine,
  • Nosebleeds,
  • Lameness,
  • Minor hemorrhages on the skin or mucous membranes and that we call petechiae …

Care is required because the dog remains a carrier of the bacteria if it is not treated even if, luckily, it overcomes the acute phase of ehrlichiosis. A relapse is then to be feared.

Prevention of parasitic diseases in dogs

The dog protection against parasitic diseases inevitably involves simple preventive measures. It should of course be avoided that it is stung or bitten by vector parasites. Ask the veterinarian for pest control perfectly adapted to the dog according to his age for example. In addition, upon returning from each ride, the master must brush carefully his dog.

At the same time, it is necessary inspect the skin of his animal to ensure that no parasite has settled there during an outing. Ticks should be removed immediately with a tick remover. It is also possible to entrust this task to the veterinarian. At certain times of the year, it is better avoid certain areas because they are very infested by insects that can sting or bite a dog.

Finally, it is recommended to do everything possible to do not attract mosquitoes in order to protect his dog but also humans. They are virulent and vectors of serious diseases. For example, you should not leave water in the saucers placed under the flowerpots, because the stagnant water attracts mosquitoes.