The immune system consists of the cells and organs that are involved in protecting the body from foreign invaders. There are two parts to this system: the innate immune system and the adaptive immune system. The innate immune system is very non-specific and attacks bacteria and viruses of any type. Immune cells recognise foreign invaders and trigger the release of chemicals that kill and dispose of them. The adaptive immune system is more specific; it’s capable of remembering previous exposure to infectious organisms and its cells quickly produce antibodies to destroy them. This previous exposure may occur through natural infection or through vaccination.
It’s essential that your dog has a healthy immune system that’s capable of responding to threats in order to protect them from ill health. Without this, they are at risk of illness from invaders like bacteria and viruses because their body can’t effectively kill and eliminate them.
Worms and the immune system
Worms are a relatively common cause of disease in dogs. Some worms such as whipworm inhabit the intestines, causing signs of gastroenteritis. You can expect to see vomiting and diarrhoea in infested dogs, sometimes with blood or mucous. Hookworms are also intestinal parasites but they drink blood. The result of a heavy hookworm burden is anaemia, very dark coloured diarrhoea, and a lack of energy. Tapeworms are a relatively benign worm, with the most common symptom of infestation being an itchy bottom.
If your dog is infested with worms, their immune system will recognise them as parasites and will spring into action. Its goal is to eliminate the worms, but these parasites can be tricky and have developed strategies to evade their host’s immune response. If a dog’s immune system isn’t working effectively, the parasites can survive, resulting in ongoing tissue damage and inflammation1.
Scientists have been investigating whether a vaccine can be developed to protect dogs from the effects of worms. One study showed that dogs did indeed develop an effective immune response to tapeworm infestation2. A second study indicated that vaccination of dogs with a molecule from the surface of the hookworm resulted in a reduction in both hookworm egg counts and blood loss in the dog’s intestine3. Such studies suggest that a strong healthy immune system plays a very important part in future worm control and prevention.
How to set up a preventative worm treatment
As a dog owner, the thought of your pet contracting worms of any kind is never a nice thought. Thankfully, there is a lot you can do to protect your much-loved canine friend from the effects of worms.
First and foremost, it’s important that your dog is given an effective worming treatment on a regular basis to kill any parasites they’ve acquired. Your veterinarian can recommend a suitable product and an appropriate treatment schedule. Young pups are more at risk of adverse effects from worms, so they should be treated more frequently than adult dogs.
A good diet is a critical part of keeping your dog’s immune system strong enough to cope with parasites. It has been shown that poor nutrient intake in the diet reduces immunity in both people and animals. This leaves your dog more vulnerable to the effects of disease-causing organisms. Furthermore, infection with such organisms can then affect the absorption of proteins, fats, vitamins and minerals, leading to worsened malnutrition and further affecting the immune response4. To avoid this vicious circle, feed your pet a good quality diet that’s appropriate for their age and activity level. If they receive all the nutrients they need in the right amounts, their body will be primed for defence.
Clean up faeces from your pet’s yard regularly. This will remove a potential source of re-infestation, as many worms can re-infect your dog or be transmitted from dog to dog through contaminated faeces.
Also do what you can to minimise your dog’s stress. In humans, there seems to be some correlation between stress and a poor immune function, and it appears that pets are affected in the same way5. It’s not always easy to identify the subtle signs of stress in dogs, but look for changes in mood and appetite, excessive grooming and unusual toileting habits. Causes of stress include things such as tense interactions between dogs, separation anxiety and boredom.
Protecting your dog from the effects of worms requires a multifaceted approach. Worming medication of course plays an important role, but maintaining a strong immune system is also important. Ensuring good hygiene, proper nutrition and minimal stress for your dog will give their body the best support to protect them from the many infectious organisms they encounter as they go about their day.
1 E N Meeusen (August 1999). Immunology of helminth infections, with special reference to immunopathology. Vet Parasitol. 84(3-4), 259-73. 2 M Moreno; U Benavidez; H Carol; C Rosenkranz; M Welle; C Carmona; A Nieto; J A Chabalgoity (January 2004). Local and systemic immune responses to Echinococcus granulosus in experimentally infected dogs. Vet Parasitol. 119(1), 37-50. 3 Ricardo T Fujiwara1; Bin Zhan; Susana Mendez; Alex Loukas; Lilian L Bueno; Yan Wang; Jordan Plieskatt; Yelena Oksov; Sara Lustigman; Maria Elena Bottazzi; Peter Hotez; Jeffrey M Bethony. (March 2007). Reduction of worm fecundity and canine host blood loss mediates protection against hookworm infection elicited by vaccination with recombinant Ac-16. Clin Vaccine Immunol. 14(3), 281-7. 4 Alan A. Jackson and Philip C. Calder. (June 2004). Severe Undernutrition and Immunity, Handbook of Nutrition and Immunity M Eric Gershwin MD (Editor), Penelope Nestel PhD and Carl L Keen PhD. New York City, New York: Humana Press 5 Gary M. Landsberg, DVM, DACVB, DECAWBM; Ilana Reisner DVM, PhD, DACVB. (2013) Stress and Its Effects on Health and Behavior Western Veterinary Conference proceedings 2013.
Author info: Dr Audrey Harvey is a graduate of the University of Queensland, Australia, and has worked in small animal practices for 25 years. She is particularly interested in obesity management and the role of exercise in resolving behaviour problems in dogs.