Heartworms are dangerous and common canine parasites that spend their adulthood in the right side of the dog’s heart and surrounding large vessels. Mosquitoes are the heartworms’ secondary hosts. When a mosquito sucks blood from an infected dog, it also ingests tiny heartworm microfilaria (live young) swimming in the blood. The microfilaria develop into larvae in the mosquito’s body over the period of a few weeks. The larvae migrate into the mosquito’s mouth, and when the mosquito bites another dog they enter the new host. Over a period of a few months, the larvae mature and migrate to the dog’s heart. They mate and produce more microfilaria. The microfilaria must be ingested by a mosquito to continue the heartworm life cycle; however they can survive in the dog’s bloodstream for 2-3yrs while they wait for their chance. Adult heartworms range from 4 to 12 inches long. As many as 250 worms have been discovered in a single dog heart! Adult worms block blood flow in the heart and can interfere with the performance of the heart valves. The obstruction creates strain on the heart and may cause death.
One of the primary symptoms of heartworm is a soft, deep cough that worsens with exercise. The dog may even faint after exertion. Weight loss, quick tiring and coughing up blood are other signs. However, some dogs that have just a few worms may show no outward signs at all. Treatment of heartworm infestation generally requires hospitalization because of potential complications from the death of adult worms and their possible release into the bloodstream. After the adults have been killed, further treatment is necessary to eradicate the microfilaria. Luckily several successful heartworm preventatives are widely available. Two types of pills are prescribed to prevent heartworm, one given daily and the other given once a month. Dogs who receive the medications must be free of the disease when they start the program. Your vet can give your dog a test, called the occult heartworm antigen test, which identifies the presence of adult worms even if no microfilaria are present. This is today’s best, most dependable diagnostic test for heartworm.
Roundworms are whitish worms from 1 to 7 inches long that look like wiggling strands of spaghetti. Roundworm eggs can live for several years in the soil and can infect a host from there or directly from infected stool. A dog ingests the eggs, which hatch in the intestine. Larvae first migrate to the lungs. After further development, they either return to the intestine to become adults or become encysted into the dog’s tissues and go into dormancy. Roundworms usually don’t cause too much trouble in adult dogs, but they can be life-threatening to puppies. Most puppies are born with some worms.
Even de-worming the dam before pregnancy can not prevent infestation because dormant worm cysts in the dam’s tissues, triggered by pregnancy, release larvae carried in the bloodstream to the unborn puppies. Larvae may also be present in the dam’s milk. Some drugs to control the larvae are now available for the dam to take late in pregnancy and in the early days after birth. Consult your vet. Symptoms of round worm infestation include swollen belly, dull coat, diarrhea, weight loss, and worms in the stool or vomit. Puppies should be de-wormed for the first time when they receive their first shots at 6 wks old and then 2-3 more treatments to follow. Your vet will let you know exactly what he is going to do!
Tapeworms are common parasites that attach themselves to the wall of a dog’s small intestine with hooks and suckers. The body of the tapeworm is made up of small segments with eggs inside. The segments loosen and are released from the body in the feces. If you notice small whitish segments that resemble grains of rice in our dog’s stool or around his anus, he probably has a tapeworm. Other signs of infestation are dull coat, diarrhea and weight loss. The tapeworm commonly enters the dog through a flea bite. Therefore, flea control helps prevent tapeworm infestation. Other sources of infection include raw meat and raw fish.
Ticks are arthropods which feed on blood. Adults lay their eggs either on the ground, in crevices, or in your carpet. The eggs hatch into larvae, which feed on a variety of small animals such as mice and birds. After a nymph stage and another feeding period, they become adults. The adult female may sit on tall grass or on branches or fences, waiting for a larger animal to pass by. Once on the host animal, she gorges on the host’s blood, growing to as much as 300 times her initial weight. She then mates and drops off to lay her eggs.
Ticks carry diseases. The deer tick is a carrier of Lyme Disease. Ticks can also transmit Rocky Mountain spotted fever, Bayesian (a blood cell parasite), encephalitis, and cause tick paralysis. These little brown pests can infest your home if left unchecked. Spray your dog with insect repellent before walking in the woods or in grassy or weedy areas (Spray yourself too!). Check your dog and yourself thoroughly for ticks when you return.
One of the best protections against Lyme disease is thorough grooming, because ticks can only spread the disease after the second day of their 3-4 day feeding period. Brush out your dog’s coat and check behind his ears and under his arms after you return home. Check again several hours later and again the next day. Ticks are easier to see and feel when they are engorged. If you do find a tick on your dog, kill the tick first by swabbing him with alcohol, gin or fingernail polish, or flea and tick spray. Wait about ten minutes to be sure it’s really dead, Then firmly grasp the dead tick with a tweezers or tissue and pull steadily until it lets go. If the head stays in the dog, there will probably be some localized redness and swelling. Be careful not to get any of the tick’s bodily fluids on your skin as some tick diseases can be transmitted this way.
There are many products on the market that are effective against ticks. Preventic is a collar that releases a chemical damaging the tick’s nervous system. It paralyzes ticks so they fall off the dog. Defend Exspot(R) is a liquid applied as a single dose to the dog’s back between the shoulder blades. This product protects against both fleas and ticks. Ask your vet, he will know what you need!
Other External Parasites
Fleas – Fleas are very widespread, common parasites found in dogs, cats and even humans. They feed on the host’s blood by biting. The bites cause itching and sometimes allergic reactions. Fleas reproduce at an alarming rate and can quickly infest your house and yard. The only effective way to control these pests is to eradicate them on several fronts. Fleas must be controlled on the dog, in his bedding, and in the environment.
Lice – Lice are much less common than fleas and ticks. They generally infest ill-groomed dogs in poor condition. Lice cause severe itching and sometimes anemia. These irritating pests can often be found in matted areas of the coat and on the head and anal areas. There are two types of lice: biting lice and sucking lice. The biting lice feed on skin cells and the sucking lice feed on blood. Lice are pale colored insects about 1/10 inches in length. They lay small white eggs called nits on the dog’s coat hairs. Though the nits look a bit like dandruff to the naked eye, examination with a magnifying glass shows the nits are rounded and attached to the hairs. Lice can be killed with flea dips. A dip every 10 days for a month should solve this problem.
Ear Mites – Ear mites are very tiny creatures that take up residence in the dog’s ear canal. These small, white moving dots cause itching and a reddish-brown discharge. They spread rapidly among cats and dogs in a household. See your veterinarian if your dog is scratching at his ears or shaking his head, or if you notice the characteristic discharge. (Ear mites are more common in puppies. In adult dogs, head shaking may be more likely due to a yeast or bacterial infection.)You will probably need to treat the entire dog with an insecticide as well as treating his ears, since ear mites sometimes migrate to other parts of the dog’s body.
Mange Mites – Several types of mites can infest our canine friends. Sarcoptic mange is one of the most common mite problems. Intense itching results when the female mange mites burrow into the dog’s skin to lay eggs. Irritation caused by the mites and by the dog’s rubbing, scratching and biting makes the skin red with oozing scabs. In advanced cases, the skin thickens and becomes dark colored. The complete mange mite life cycle takes only 17-21 days and all happens on the same host, so this condition can spread rapidly. Sarcoptic mange is treated with insecticidal dips or with a new treatment where the dog is injected with Ivermectin. Sarcoptic mange is difficult to diagnose because the mites are hard to find on skin scrapings. Demodectic and cheyletiella mites can also cause problems for dogs. Demodectic mites are usually found on puppies and cause loss of hair around the eyes and head. This problem can be very serious. If your dog is suffering from red, scaly looking areas, patches of hair loss, or itching, suspect mites. See your veterinarian immediately some mites can infest humans. Luckily we live in a world where we can control canine parasites. Use preventive measures such as good grooming and insecticide barriers whenever possible to keep problems from getting started in the first place.