Internal Parasite Control

Intestinal Worms

Intestinal worms are everywhere! Protecting working dogs from intestinal worms is not only essential for their health, but importantly, this also protects humans and stock (cattle, sheep and goats) from infection. The major intestinal worms encountered by working dogs are:

  • Tapeworms
  • Roundworms
  • Hookworms
  • Whipworms

Tapeworms

Tapeworms are flat, segmented worms that attach to the wall of the small intestine and absorb nutrients. There are many different species of tapeworms, with dogs becoming infected in all cases when they ingest a tapeworm-infected intermediate host. Intermediate hosts become infected following ingestion of tapeworm eggs in the environment that have been excreted in the faeces of an infected dog. In the intermediate host, larval cysts can form in muscles as well as organs, which can reduce meat quality, resulting in economic losses for meat producers.

Signs of a Tapeworm Infection

In the dog, most tapeworm infections are asymptomatic, with dogs acting as a source of contamination in the environment, which can lead to the infection of other animals (e.g. sheep). Tapeworms can rob nutrients from a host, cause anal irritation (as the tapeworm segments are released) and diarrhoea.

 

 Hydatid Tapeworm Lifecycle

For more information on T. ovis (Sheep Measles), click here.

Hydatid Tapeworm Lifecycle

 

Controling hydatid tapeworm
It is important to prevent hunting and scavenging in working dogs – ways to reduce this including removing carcasses and faeces from the farm and restricting the movement of these dogs when not working. Working dogs should not be fed raw offal.

Treatment and Prevention

Most veterinarians recommend the following treatment regime with a knock-down wormer such as Drontal®.

However, to control hydatid tapeworm and sheep measles, dogs need to be treated every 6 weeks. For the zipper tapeworm, which is found predominately along the Queensland coast, 4 to 6 times the dose of praziquantel is required. This can be given in the form of Droncit®. FOR MORE INFORMATION ON DRONTAL, CLICK HERE!

Roundworms

Roundworms live and reproduce in the small intestine, feeding on the intestinal contents. Dogs are infected by ingesting eggs passed in the faeces of an infected dog (or cat) or ingesting an infected carrier host (rodent, bird). Puppies can become infected in the womb or following birth through the milk. Roundworm infection is most common in puppies causing weight loss, a poor quality coat and a pot belly. Other signs of roundworm infection include:

  • Loss of appetite
  • Vomiting
  • Diarrhoea
  • Cough
  • Depression
  • Gastrointestinal blockage
  • Death

Adult worms can produce up to 200 000 eggs per day, which are passed in the faeces and contaminate the environment. Eggs in the environment can remain infective for several years.

Hookworms

Hookworms are blood-sucking worms that use ‘teeth’ to attach to the small intestinal wall, causing damage to the intestines. Dogs are infected by ingesting larvae in the environment, or penetration of larvae in the environment through the skin. Puppies can also be infected via the milk from an infected female dog. The signs of hookworm infection include:

  • Anaemia
  • Diarrhoea, blackish faeces
  • Anorexia
  • Depression
  • Wasting

Death, from blood loss, can occur in young dogs before the eggs can be detected in the faeces. Produce up to 30 000 eggs per day which are passed in the faeces and contaminate the environment

Whipworm

Whipworms are blood-sucking worms that develop in the large intestine. Dogs are infected by ingesting eggs found in the environment. Most infections do not result in any signs, however heavy infections can lead to:

  • Loss of appetite
  • Weight loss
  • Abdominal pain and straining
  • Foul-smelling diarrhoea, bright red with fresh blood
  • Anaemia
  • Whipworms produce up to 2000 eggs per day which are passed in the faeces and contaminate the environment. Eggs can remain infective in the soil and surrounding environment for years.

Control

Choose a wormer that not only kills existing worms but also prevents new infections. Advocate® is effective against immature and mature adult worms, as well as larval stages. Treat all animals regularly and as directed (dose to body weight) and regularly remove faeces from the environment. Drontal® kills all major gastrointestinal worms and is Australia’s #1 vet recommended Allwormer. It is available in a chewable formation or as tablets for treatment every 3 months.

Zoonosis

 A zoonosis is a disease that can be transferred from animals to humans.

  • Hydatid tapeworm: following ingestion of hydatid eggs, larvae are released and migrate through the body, forming large cysts in organs. Symptoms vary depending on the organ affected, but mortality can be >90% in advanced disease
  • Hookworms: larvae penetrate the skin causing cutaneous larval migrans (inflamed and itchy migration tracts in the skin
  • Roundworms: following ingestion of eggs, larvae are released and migrate throughout the body causing organ damage. Symptoms can include abdominal pain, respiratory failure and blindness.

Heart Worms

Heartworm disease is transmitted between dogs by mosquitoes and infection in dogs is potentially life-threatening. Heartworm disease has the highest prevalence in tropical and subtropical coastal areas, however it is found in most parts of Australia wherever mosquitoes are found. Heartworm treatment is difficult and very costly, so protecting working dogs from this nasty parasite is vital.

The Lifecycle

Adult heartworms live in the heart and pulmonary arteries (which carry blood from the heart to the lungs). Adults live up to 7 years and grow up to 30cm in length. Mature adults produce and release microfilaria into the bloodstream from approximately 6 months post-infection. Microfilaria can survive in the systemic circulation for 2 years. Adult mosquitoes feeding on the blood of an infected animal ingest the microfilaria, and further development of the microfilaria then occurs in the mosquito to infective larvae. Infected mosquitoes will then feed on another animal, and transmit the heartworm larvae into the healthy animal. Mature adults develop and migrate to the heart and surrounding vessels.

Signs of Heartworm Infection

Signs can vary from none to severe compromise.

  • Moderate severity:
    • Exercise intolerance
    • Coughing occasionally
    • Possible anaemia
  • Severe:
    • Respiratory rate and heart rate increased at rest
    • Coughing regularly
    • Exercise intolerance/tiredness
    • Poor body condition/weight loss
    • Pale gums due to anaemia
    • Fainting     
    • Nose bleeds    
    • Enlarged abdomen from fluid build-up in heart failure
    • Death


Control and Prevention

Monthly treatment with Advocate® will provide protection against heartworm infection in working dogs. It is safe for use in ivermectin-sensitive breeds of dogs (e.g. collies) and in heartworm-positive dogs. It gives you peace of mind. When used monthly, Advantix® kills and repels mosquitoes that not only cause irritation to your dog, but also transmit this deadly parasite when they feed. However, controlling mosquitoes alone will not prevent heartworm infection, so it is vital that a product that is registered for heartworm is used frequently and as directed.