Spring and Summer Pests and Disease Threats

 

As spring and summer approach, our pets tend to spend more time outside enjoying the warmer weather. Many pests that can endanger our pets become more prevalent with the warmer weather. It is important to start planning for and preventing these threats now.

 

Heartworm (Dirofilaria immitis) is a parasite that lives in the pulmonary arteries, affecting the heart and lungs. It causes signs of heart disease such as cough and exercise intolerance. This parasite has a complex life cycle with stages taking place in the mosquito and the dog. Transmission occurs when a dog is bitten by a mosquito that is carrying heartworm larvae. These larvae eventually mature into heartworms in the dog.

In the past, heartworm disease in cats has not received much attention. However, research over the past several years suggests that heartworm disease is a very serious health threat to cats and more common than previously thought. Cats are not considered a normal host for heartworms so the disease can develop differently in cats. Most cats with heartworm disease have only 1-2 adult worms compared to dogs that can have many worms present. These worms cause severe inflammation and irritation to the lungs. Cats may present with signs of heart disease, asthma, or more commonly vomiting. Due to the significant affects on the lungs and no safe treatment available to remove the worms, heartworm disease in cats is very serious and can be more life-threatening than in dogs.

Treatment of heartworm consists of hospitalization, 2 injections of an arsenical compound, Melarsomine, and close monitoring for possible side effects. This treatment is not recommended for cats. Due to the fact that this disease is fatal if not treated in a timely manner and treatment is dangerous, prevention is crucial.

Heartworm prevention is available as a once monthly chewable tablet (we typically use Interceptor) that kills larvae that may be transmitted when a mosquito bites your dog. Topical products (such as Revolution and Advantage Multi) that are combined with a flea preventive are also available; these are most commonly used for cats. All dogs over 6 months of age need to be tested prior to starting heartworm prevention as use of the medication can cause a life-threatening anaphylactic reaction if your dog is already carrying heartworm. After starting on prevention your dog should be tested on a routine basis to ensure that the prevention is working effectively. While testing of cats prior to starting prevention is not necessary, it is recommended as part of general health screening.

 

Lyme disease is a bacterial infection that is transmitted by ticks, specifically deer ticks. Typically, a tick needs to be attached for 36-48 hours for transmission of the bacteria. Signs of Lyme disease include fever, decreased appetite, depression or pain. A simple blood test can be performed at the hospital to determine if your dog has been exposed. It takes about one week to one month after tick exposure for a positive response. Most animals will continue to test positive for months to years following initial diagnosis.

Treatment for Lyme disease includes antibiotics, usually doxycycline, over a three week period. Most dogs will improve within a few days of starting the medication. Re-infection and relapses can occur, requiring further treatment. Other organs in the body, especially kidneys, can be affected by the disease due to the body’s immune response. This can be severe and potentially life-threatening so it is very important to test and treat any dog that is showing signs of Lyme disease.

Preventing exposure to ticks is the first step in Lyme disease prevention. It is important to use a topical flea and tick preventive every month. Cats are also susceptible to a variety of tick-borne diseases and appropriate flea and tick preventive should be used for them as well. Additionally, there is a vaccine available for Lyme disease. Initially, your dog will need two doses given three weeks apart, followed by a yearly booster.

 

Fleas are commonly known to be a nuisance but can also cause several health problems in addition to itching and irritation. Many cats and dogs show an allergic reaction to flea bites causing them to be intensely itchy. Animals suffering from flea bites develop hair loss, red bumps and open sores due to the intense scratching and licking. This can lead to skin infections requiring antibiotics in addition to medication to stop the itching. Fleas are known to carry many disease causing organisms, especially bacteria that can attack red blood cells leading to anemia. Parasites, such as tapeworms are also carried by fleas.

The most important part of treatment is treating the pet and environment to get rid of the fleas. Topical flea preventions, such as Frontline or Advantage are very effective and safe for killing fleas. Many of the over the counter products tend to absorb systemically into the body with potential for toxicity problems, most notably neurologic signs. Cleaning carpets, bedding and furniture are also important to remove eggs that will hatch and develop into more adult fleas. Sprays and flea bombs are also useful for killing fleas in the environment but must be used with caution as cats and dogs can be sensitive to some of the chemical pesticides.

 

Please contact our office if you have any questions regarding heartworm, flea/tick prevention or any of these disease threats.

Dr. Lisa Tubman