Parasites in pets are a common and avoidable problem. The problems they cause can vary from minor irritation to serious illness, and some of them can also be passed to humans.
Intestinal worms: There are several worms in this category including:
Hookworm (Ancylostoma, Uncinaria) Hookworms live in the intestines, but also migrate throughout the body. They live off blood that they suck from the intestinal wall, and so can cause anaemia (particularly in pups), as well as diarrhoea. The infection can pass by larvae being ingested or passing through the skin, or from mother to pup via her colostrum. They can also infect humans, where they migrate through the skin leaving characteristic squiggly trails.
Roundworm (Toxocara) Roundworms live in the small intestine, and cause diarrhoea, abdominal pain, and weight loss. Infection can pass to unborn pups through the placenta, and also through the colostrum, or by ingesting eggs. Young pups can become very sick. Humans can become infected, where the larva migrate through the whole body, and in some cases have been known to lodge in the eye and cause blindness.
Whipworm - (Trichuris) This worm lives in the large intestines, and can cause diarrhoea with blood. Eggs can live in the environment for years and still cause infection.
Tapeworm (Dipylidium, Echinococcus) The Dipylidium tapeworm, known as the flea tapeworm, is spread via fleas the fleas ingest eggs, and then the dog ingests the flea while grooming. It occasionally can cause diarrhoea, and irritation around the anus. Echinococcus, known as the hydatid, can cause enteritis in dogs when present in large numbers. Our main concern however is what happens when humans become infected from their dog the larvae migrate and develop cysts that can become very large, in places like the liver and lungs, and occasionally the brain, spleen or spine. They can cause very serious disease and death, and treatment involves drugs and usually surgery, multiple times in some instances, and there is the risk of severe reactions to the contents of the cyst if it bursts. The eggs can survive for months if environmental conditions are correct.
Other worms: There is one Main worm in this category:
Heartworm -(Dirofilaria immitis) Heartworms live in the heart and blood vessels going to the lungs. The larvae are spread by mosquitoes. When a mosquito bites an infected dog they ingest the larvae, which develops, and is spread when the mosquito feeds again on a new dog. The larvae then develop in the fat or muscle before spreading into the circulation and moving to the heart. Disease results from the worms being in the heart and vessels they cause irritation and block the vessels, which interferes with blood flow. Occasionally one dies and lets go, so it flows through until it comes to a smaller vessel, and blocks off blood flow. It is an easily preventable disease, using daily or monthly tablets or yearly injections, but is difficult to treat.
Ectoparasites
Fleas- Fleas are quite an annoyance to most pets and pet owners, and can cause serious problems for very young animals and flea-allergic animals. Fleas feed on the blood of their host, causing irritation when they bite, and also spread flea tapeworm between dogs and cats. Most fleas are not the adults that live on the animal, but are eggs, larvae and pupae in the environment.
Mites there are several types of mites that can infest dogs and cats, and most cause extreme itchiness and hair loss, and the skin can become infected as a result. Some mites can be spread from animal to animal, and even animal to human, while others cannot.
Ear mites also cause itchiness in the ears, and are particularly seen in young animals. Affected animals shake their head, scratch their ears, and may rub the sides of their head along the ground. They can cause ear infections to develop.
Ticks there are several types of ticks. They feed by attaching to a host and sucking blood. They can cause irritation and spread blood-borne parasites and cause infections where they attach. One type of tick, the paralysis tick, is found along the east coast of Australia. It secretes a substance in its saliva that causes dogs to become paralysed this shows as weakness firstly in the hind legs that progresses up the body, a change in bark, and eventually breathing problems and death.