Canine and Feline Parasites
Without protection, both dogs and cats of all ages can be harmed by a variety of parasitic infections.
- Intestinal Parasites -
Hookworms, Roundworms, Tapeworms
- Heartworms -
Life cycle, Symptoms, Detection, Prevention, Treatment
Puppies and kittens are often born with hookworms and/or roundworms, and therefore need to be dewormed as babies. Puppies & Kittens should be dewormed at least twice starting at 8 weeks and repeated again at 11 to 12 weeks. After the deworming treatments, dogs and cats should have a fecal test performed to determine if other intestinal parasites are present. Remember, intestinal parasites are worms in the stomach and guts, while heartworms are worms in the blood stream and heart.
Intestinal Parasites - Hookworms, Roundworms, Tapeworms
Hookworms cause blood loss through the intestines and can cause a puppy or kitten to die from anemia (severe blood loss). This worm can be transmitted to humans through the skin. These worms are killed with Pyrantel (Anthelban, Strongid)
Hookworms are nematode parasites of the species Ancylostoma caninum in the small intestine of dogs, and Ancylostoma tubaeforme of cats. Adult hookworms and fourth stage larvae are voracious bloodsuckers causing blood loss, anemia, and enteritis. Active worms leave bite sites in the intestines that continue to seep blood. Of special concern is infection in neonates causing acute disease. Coughing may result from larval migration to the lungs following skin penetration. In dogs, hookworms may be transmitted through a mother’s colostrum. All species of hookworms are also transmitted by ingestion of infective larvae or by skin penetration.
Clinical signs include: pale mucous membranes, dark tarry stools, constipation, loss of condition, poor appetite, dry cough, and sudden death.
Diagnosis is by fecal examination for eggs.
Treatment for hookworm infections is with Pyrantel Pamoate (Strongid-T). Iverheart Plus, or Heartgard Plus given monthly will prevent hookworm infestations. Puppies and kittens should be dewormed twice at 2-4 week intervals followed by a Fecal Parasite Exam. Breeding females should be dewormed to prevent transmission to their young. Acute cases are treated with fluid therapy and deworming, blood transfusions may be necessary.
This worm gives puppies & kittens the very large bloated belly appearance, while being thin in muscle and flesh. This worm also causes blood loss through the intestines, is present often at birth in these babies, and can be transmitted to humans. These worms are often vomited up, or pooped out. They are very fat, long and round, and curl up in a tight spiral after leaving the body. They look like fat spaghetti noodles. Owners that state they are seeing worms must be questioned as to the appearance of the worm. These worms are killed with Pyrantel (Anthelban, Strongid). Short flat looking worms are tapeworms and are killed with Praziquantel (Drontal).
Roundworms is the common name for Ascariasis. Ascariasis of dogs is caused by Toxocara canis; and in cats, Ascariasis is caused by Toxocara cati. Both species are affected by Toxocara leonina. Roundworms are relatively large robust worms up to 12 cm in length so that distension of the small intestine often leads to colic, interference with gut motility, and inability to utilize food. Because of transplacental transmission to fetuses, puppies may be born with a developing worm burden. Kittens can be infected through transcolostral transmission. Older pups and kittens may become infected by ingestion of infective eggs disseminated on premises by dams infected postgestationally.
Clinical signs include: abdominal distension, colicky pain, cachexia, anorexia, scanty feces, coughing due to larval migration, weakness, sudden death.
Diagnosis is by fecal examination for eggs.
Treatment for roundworms is by deworming twice with Strongid or other anthelmintics. Giving Iverheart Plus or Heartgard Plus will prevent infestation. Bitches and queens should be treated to prevent subsequent litter infections. Roundworms may be seen in a pet’s stool. They look like thick strands of spaghetti, with round bodies. They usually coil up tightly when defecated out of the body. They can be from 3"-10" long.
Tapeworms are caused by the pet eating/swallowing fleas carrying the tapeworm eggs. This is the only way to get tapeworms, by eating infected fleas. Tapeworms crawl out of the anus, and are found crawling on fresh stools. They are very itchy, and cause the pet to drag their rears on the ground to scratch. These worms are not dangerous, and cause no other real harm to the pet. They just "gross out" owners, and cause rear end itchiness.
We kill these worms with Praziquantel (Cestex, Droncit). We can give this drug to kill the tapeworms, but if the fleas on the pet are not killed/removed/addressed, the pet will have tapeworms again in about another month.
Tapeworm infections of the small intestines of dogs and cats are caused by Taenia pisiformis, and Dipylidium caninum. Taeniids are transmitted by predation of rabbits or rodents, Dipylidium is flea-vectored with flea maggots picking up tapeworm eggs in dog or cat feces and transmitted by adult fleas when ingested by dogs or cats. There is no apparent harm done to the dog or cat by tapeworms except for perianal pruritus. Owners find the tapeworm segments unsightly, as they crawl from the anus periodically and stick to the pet's hairs.
Clinical signs include: dragging or rubbing the anus on the ground, and visible tapeworm segments on the feces. Causes or risk factors are eating viscera of rabbits or rodents, and fleas in the environment.
Treatment for tapeworms is with Praziquantel (Drontal) 5mg/kg once. Tapeworms are often described as looking like "grains of rice". They are flat, usually ½" or shorter, and can be seen crawling out of the rectum, or moving on freshly defecated stool.
External Parasites - Fleas, Ticks, Mites
Fleas can infest dogs and cats, and in areas of moderate to severe infestation, people can be bitten by fleas. An infestation that is severe and not treated can cause death to a pet due to blood loss (anemia). Also, histamine-like compounds in flea saliva irritate the skin and allergies to fleas develop in both dogs and cats. There is no cure for flea allergy hypersensitivity, only management through flea control.
The latest products in the war on fleas are Advantage & Frontline. These flea treatments will be discussed in the section on product information.
Please note: Advantage & Frontline are two products that are safe for both dogs and cats – as opposed to over-thecounter products such as Spotton and Bio Spot.
Ticks can cause Lyme Disease and other illnesses. It is important to control and prevent ticks from infesting pets, homes & humans. Frontline is the product to recommend for use on dogs & cats with flea or tick problems, or if the pet spends time in environments with fleas and ticks. Frontline must be used if ticks are a problem as Advantage cannot kill ticks.
There are numerous types of tick that can parasitize dogs and cats. Ticks feed only on the blood of their hosts, and are arthropods, closely related to spiders, scorpions and mites. Ticks can spread bacteria, fungi, protozoa, viruses, rickettsiae, filarial nematodes and spirochetes.
Examples of diseases spread by ticks are: Lyme Disease, Rocky Mountain Spotted Fever, Tick Paralysis, Ehrlichiosis, Babesiosis, Borreliosis, and others.
There are numerous types of mites that affect pets, many of which can be transmitted to people.
A. Ear Mites
The ValueVet at PETCO treats ear mites with Acarexx. Acarexx is usually two-time treatment. However, if multiple pets in the household are infected, all will have to be treated in order to eliminate the infection. Kittens are more prone to earmites. All kitten owners should be questioned about the presence of black "coffee ground"-like substance in their kitten’s ears. The veterinary assistant should remind the veterinarian to check all kittens for ear mites. IF present, the ear should be cleaned out with a swab & peroxide, and the Acarexx is applied for ear mite treatment. The pet should be rechecked in 1 month to see if the infection was cleared.
B. Mange Mites
The ValueVet at PETCO does not treat mange, but it should be noted that mites can be a cause of many skin problems. Dogs that arrive at our clinics and are bald, or have sever hair loss may have mange. Employees should be sure to disinfect the table and their hands after handling animals with hair loss.
Mange in animals can be caused by one of two different mites: Sarcoptic or Demodectic.
Sarcoptic mange mites can be spread to other animals and to people, while Demodectic mange mites cannot. Both types of mange cause hair loss and itching.
Heartworm disease can infect both cats and dogs. This disease is spread by mosquito bite. Heartworms are 12 inch worms that live in the heart and impede the heart’s functioning. Dogs can develop heart failure over several years and enevatibly die wihout treatment.
The American Heartworm Society is now recommending year-round prevention, even in seasonal areas. One reason for this is compliance – to make sure the medicine has been given properly by the pet owner. In addition, most monthly heartworm preventives have activity against intestinal parasites. Many of these same intestinal parasites that infect dogs can also infect people, with estimated infections occurring in three to six million people every year. So this added benefit of monthly deworming makes great sense.
A. The Life Cycle
First, adult female heartworms release their young, called microfilariae, into an animal's bloodstream. Then, mosquitoes become infected withmicrofilariae while taking blood meal from the infected animal. During the next 10 to 14 days, the microfilariae mature to the infective larval stage within the mosquito. After that, the mosquito bites another dog, cat or other susceptible animal, and the infective larvae enter through the bite wound. It then takes a little over 6 months for the infective larvae to mature into adult worms. In dogs, the worms may live for up to 7 years. Microfilariaecannot mature into adult heartworms without first passing through a mosquito.
B. Signs and Symptoms
For both dogs and cats, clinical signs of heartworm disease may not be recognized in the early stages, as the number of heartworms in an animal tends to accumulate gradually over a period of months and sometimes years and after repeated mosquito bites.
Recently infected dogs may exhibit no signs of the disease, while heavily infected dogs may eventually show clinical signs, including a mild, persistent cough, reluctance to move or exercise, fatigue after only moderate exercise, reduced appetite and weight loss.
Cats may exhibit clinical signs that are very non-specific, mimicking many other feline diseases. Chronic clinical signs include vomiting, gagging, difficulty or rapid breathing, lethargy and weight loss. Signs associated with the first stage of heartworm disease, when the heartworms enter a blood vessel and are carried to the pulmonary arteries, are often mistaken for feline asthma or allergic bronchitis, when in fact they are actually due to a syndrome newly defined as Heartworm Associated Respiratory Disease (HARD).
Heartworm infection in apparently healthy animals is usually detected with blood tests for a heartworm substance called an "antigen" ormicrofilariae, although neither test is consistently positive until about seven months after infection has occurred.
Heartworm infection may also occasionally be detected through ultrasound and/or x-ray images of the heart and lungs, although these tests are usually used in animals already known to be infected.
Because heartworm disease is preventable, the AHS recommends that pet owners take steps now to talk to their veterinarian about how to best protect their pets from this dangerous disease. Heartworm prevention is safe, easy and inexpensive. While treatment for heartworm disease in dogs is possible, it is a complicated and expensive process, taking weeks for infected animals to recover. There is no effective treatment for heartworm disease in cats, so it is imperative that disease prevention measures be taken for cats.
There are a variety of options for preventing heartworm infection in both dogs and cats, including daily and monthly tablets and chewables, monthly topicals and a six-month injectable product available only for dogs. All of these methods are extremely effective, and when administered properly on a timely schedule, heartworm infection can be completely prevented. These medications interrupt heartworm development before adult worms reach the lungs and cause disease.
It is your responsibility to faithfully maintain the prevention program you have selected in consultation with your veterinarian.
Usually, all but the most advanced cases of heartworm disease can be successfully treated in dogs. Currently, there are no products in the United States approved for the treatment of heartworm infection in cats. Cats have proven to be more resistant hosts to heartworm than dogs, and often appear to be able to rid themselves of infection spontaneously. Unfortunately, many cats tend to react severely to the dead worms as they are being cleared by the body, and this can result in a shock reaction, a life-threatening situation. Veterinarians will often attempt to treat an infected cat with supportive therapy measures to minimize this reaction; however it is always best to prevent the disease.
Adult heartworms in dogs are killed using a drug called an adulticide that is injected into the muscle through a series of treatments. Treatment may be administered on an outpatient basis, but hospitalization is usually recommended. When the dog is sent home, exercise should be limited to leash walking for the duration of the recovery period, which can last from one to two months. This decreases the risk of partial or complete blockage of blood flow through the lungs by dead worms.
Re-infection during treatment is prevented by administration of a heartworm preventive. These preventives may also eliminate microfilariae if they are present. Dogs in heart failure and those with caval syndromerequire special attention.
Information and images provided by: The American Hertworm Society.
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