Flukes In Dogs – Symptoms & Treatment

Flukes are a zoonotic, parasitic infection caused by Trematodes flatworms of the genus Trematoda. Trematodes commonly known as flukes or flatworms infect many species worldwide. The term ‘Trematodes’ is derived from the Greek word ‘trematos’, which means ‘pierced with holes’, referring to the attachment and “sucker” nature of the pathogens.

Based on the primary system they affect, Trematodes can be classified into 3 types: pulmonary, Hepatopancreatic flukes, and gastrointestinal (GI). The pathophysiology and epidemiology of the digenetic flukes that infect dogs are complex and varied.

Trematodes that infect dogs have indirect life cycles. To reach the adult stage of development, they require 1 or 2 intermediate hosts and they are reliant on water access. Pre-patent periods are species-centric and it is an average of 2 weeks. The trematodes shedding their eggs in the feces of the infected dog (definitive host) begin the life cycle.

In the definitive host, the eggs are formed by sexual reproduction and can be identified by their operculum (brown shells and a small-cap). They hatch to a fully developed, free-swimming ciliated form in water called the miracidium. The emerging larval form penetrates the primary intermediate host, which is usually a snail of the Pomatiopsis genus. At the site of penetration, it develops into a sac-like structure called sporocyst, and encapsulated larva develops and it is called a redia. After about six to seven weeks in the first intermediate host, a cercaria is formed through asexual reproduction and it is geared up to infect the second intermediate host.

The second intermediate host can be anything, it could be another snail, amphibian, bivalve, a freshwater crab, or freshwater fish ( crayfish). In the second host, cercaria encysts mature into an encysted metacercaria. When the second intermediate hosts are ingested by the final host organisms (dogs and cats), they become infected with the adult trematode.

Flukes symptoms vary depending on the affected location

Lung flukes

• Coughing or difficulty breathing
• Bloody mucus
• Pneumonia
• Pneumothorax (collapsed lung)
• Bronchiectasis (the bronchioles damage)
• Lethargy

Intestinal Flukes

• Abdominal pain
• Acute hemorrhagic diarrhea
• Anorexia
• Loss of weight
• Tiredness
• Excessive thirst
• Excessive urination

Hepatopancreatic Flukes

• Chronic pancreatitis
• Indigestion
• Abdominal pain
• Nausea
• Constipation or diarrhea

Commonly used intestinal parasitic medications are praziquantel, fenbendazole, nitroscanate, and epsiprantel. They have relatively few side effects and are well-tolerated by most dogs.

Access the severity of the condition, look into your dog's bowel movements, and check whether the things escalate or clear up.

Contact your vet right away if your pet has frequent bouts of diarrhea in a short time period.

Lung flukes: Fenbendazole (50 mg/kg q24h PO for 10-14 days), albendazole (20 mg/kg q11 for 10 days) or praziquantel (23 mg/kg q8h PO for 3 days).

Intestinal flukes: tetracycline (22 mg/kg q8h PO for 21 days), doxycycline (5 to 10 mg/kg q12h PO or IV for 21 days) for the bacterial infection or praziquantel (10 to 30 mg/kg, one dose PO or SC).

Hepatopancreatic flukes: praziquantel (10 to 30 mg/kg, one dose PO or SC).

Blood flukes: fenbendazole (24 mg/kg q24h PO for 1 week) or praziquantel (10 mg/kg q8h PO for 2 days).

• When your dog has had one or two episodes of diarrhea, don’t feed your dog for some time and let your dog recover (for 12 - 24 hours).
• Reintroduce a bland diet that requires minimal digestion for a day or two. Feed cooked white rice and little white meat such as chicken or fish.
• Offer each meal in small quantities every 3-4 hours - consider 2 tablespoons for small dogs and 3 or 4 tablespoons for larger dogs.
• When your dog is feeling good, slowly reintroduce its regular food.

• Takes steps to cut down the access of dogs to swamps or near water bodies where there is decayed organic material and foliages, especially when the soil is remains damp all the time and not exposed to sunlight.
• When going for walks, keep your dog away from water bodies and swampy areas in the woods.
• Maintain your lawn or garden. Keep it neat and clean to avoid unwanted complications.
• Herding dog's access to the feeding areas should be restricted, including pastures should be reduced.
• Feed high-quality food and exercise regularly.

There is no confirmed breed predisposition.

1. Causes:

• Transmission of larvae from intermediate hosts to dogs
• Transfer of eggs within contaminated water

2. Types:

Lung flukes: Paragonimus Kellicotti and P Westermani.

Intestinal flukes: Nanophyetus Salmincola, Alaria Marcianae, Alaria Americanae/Canis, Alaria Arisemoides, Cryptocotyle lingua, and Apophallus Venustus.

Hepatopancreatic Flukes: Metorchis Conjunctus, Clonorchis Sinensis, Opisthorchis Tenuicollis, and Eurytrema Procyonis.

Blood flukes: Heterobilharzia Americana.

3. Morbidity:

1. Large breed dogs with outdoor access living in endemic regions are at higher risk.
2. Herding, and hunting dogs with close proximity to fresh water, Aquatic, warm areas, and Subtropical climates.
3. Intestinal flukes are spread from animal to animal and are contagious.

4. Mortality:

Untreated Canine flukes have a high case fatality rate in dogs and lead to long-term complications. If the lungs are involved, the mortality rate will be higher.

5. Diagnosis:

• Blood and urine cultures
• Specific blood tests
• X-rays, ultrasound, or CT scan
• Stool sample for testing.

6. Differential diagnosis:

• Tuberculosis
• Biliary colic
• Biliary cirrhosis
• Liver abscess
• Liver cysts
• Budd-Chiari syndrome
• Primary hepatic carcinoma

7. Prognosis:

The prognosis for flukes is really good. Most dogs undergoing treatment will recover within a few weeks. If left untreated, severe cases of flukes can be fatal for dogs, so head to your vet immediately.

It’s better to set up an appointment with your veterinarian if you notice-

• Labored breathing
• Licking of the perianal and anal areas
• Itching around the anus

1. Lean Protein and Low-fat meats (ratio of omega-6 to omega-3 fats = 5:1)
2. White Rice, Boiled boneless, skinless chicken breast meat
3. Potatoes and Pumpkin (canned or pureed)
4. Probiotics (yogurt, Goat's Milk, fermented vegetables, kefir with live cultures)
5. Mashed boiled potatoes, carrots
6. Bananas, Apples, Seaweed

The prognosis for systemic flukes is varies inversely with delay in detection, severity and evidence of failure of vital organs. For cases with localized infections, the prognosis is generally good.