Heartworm Disease: Getting To The Heart Of The Matter

Heartworm Facts:
-Heartworm disease (dirofilariasis) is a serious and potentially fatal disease in dogs caused by a worm called Dirofilaria immitis.

-The female worm is 6 to 14 inches (15 to 36 cm) long and 1/8 inch (5 mm) wide; the male is about half the size of the female.

-Heartworms are found in the heart and large adjacent vessels of infected dogs. One dog may have as many as 300 worms.

Read on to find out how this potentially deadly parasite is spread and what you can do to prevent it from affecting your dog.

How Heartworms Get into the Heart

Adult heartworms live in the heart and pulmonary arteries of infected dogs. They have been found in other areas of the body, but this is unusual. In a dog they can survive up to 5 years and, during this time, a female worm can produce millions of young (microfilaria). These microfilaria live in the bloodstream, mainly in the small blood vessels, where they wait for a mosquito to bite the infected dog so they can complete their life cycle. Microfilaria in this stage are not conidered to be infective as they are unable to fully mature without the intermediate mosquito host.  However, even though they are not considered "infective" they can still cause other problems for the infected dog.

Once a female mosquito bites an infected dog and ingests the microfilaria during a blood meal the microfilaria continue developing for another 10 to 30 days before entering the mouthparts of the mosquito. After entering the mouthparts of a mosquito the microfilaria are now considered "infective." If the microfilaria are transmitted to a dog during this stage they will complete their life cycle and grow into an adult worm.

Geography

Canine heartworm disease occurs all over the world. In the United States, it was once limited to the south and southeast regions. However, the disease is spreading and is now found in most regions of the United States and Canada, particularly where mosquitoes are prevalent.

Contagion

The disease is not spread directly from dog to dog. An intermediate host, the mosquito, is required for transmission. Spread of the disease therefore coincides with the mosquito season. The number of dogs infected and the length of the mosquito season are directly correlated with the incidence of heartworm disease in any given area.

It takes a number of years before a dog can show any outward signs of infection. Consequently, the disease is diagnosed mostly in 4 to 8 year old dogs. The disease is seldom diagnosed in a dog under 1 year of age because the young worms (larvae) take up to 7 months to mature following establishment of infection in a dog.

Effects on the Dog

Adult worms: Adult worms cause disease by clogging the heart and major blood vessels leading from the heart. They interfere with the valve action in the heart and by clogging the main blood vessels, the blood supply to other organs of the body is reduced, particularly in the lungs, liver and kidneys, leading to malfunction of these organs.

Dogs infected with heartworms may not show any signs of the disease for as long as 2 years. Unfortunately, this means by the time signs are seen, the disease is well advanced. The severity of the signs of heartworm disease depend on several factors including the number of adult worms present, the location of the worms, the length of time the worms have been present, and the degree of damage to the heart, lungs, liver, and kidneys from the adult worms and the microfilaria.

The most commons symptoms are: a soft, dry, chronic cough, shortness of breath, weakness, nervousness, listlessness, and loss of stamina. All of these signs are usually most noticeable following exercise, and may cause some dogs to even faint.

Listening to the chest with a stethoscope will often reveal abnormal lung and heart sounds and in advanced cases, congestive heart failure may be apparent or the abdomen and legs may swell from fluid accumulation. There may also be evidence of weight loss, poor condition, and anemia.

In extreme cases severely infected dogs may die suddenly during exercise or excitement.

Microfilaria (Young worms): Microfilaria circulate throughout the body but remain primarily in the small blood vessels. Because they are as wide as the small vessels, they may block blood flow in these vessels causing damage to the cells and tissues beyond. The lungs and liver are two organs commonly damaged in this way.

Diagnosis

In most cases, diagnosis of heartworm disease can be made by a simple blood test that can be run in the veterinary hospital. If a postivie result comes back further diagnostic procedures are essential, in advanced cases particularly, to determine if the dog can tolerate heartworm treatment. Depending on the case, some or all of the following procedures may be recommended before treatment is started.

Serological test for antigens to adult heartworms: This is a test performed on a blood sample and works by detecting antigens (proteins) produced by adult heartworms.

Blood test for microfilariae: A blood sample could also be examined under the microscope for the presence of microfilaria. If microfilariae are seen, the test is positive. The number of microfilaria is then counted to give a general indication of the severity of the infection.

Blood chemistries: Complete blood counts and blood tests for kidney and liver function may give an indirect indication of the presence of heartworm disease if they show abormal values. These tests are also often performed on dogs diagnosed as heartworm-infected to determine the function of the dog's organs prior to treatment.

Radiographs (X-rays): A radiograph of a dog with heartworms will usually show heart enlargement and swelling of the large artery leading to the lungs from the heart. These signs are considered presumptive evidence of heartworm disease. Radiographs may also reveal the condition of the heart, lungs, and vessels. This information allows us to predict an increased possibility of complications related to treatment.

Electrocardiogram: An electrocardiogram (EKG) is a tracing of the electric currents generated by the heart. It is most useful to determine the presence of abnormal heart rhythms.

Echocardiography (Sonogram): An echocardiogram allows us to see into the heart chambers and even visualize the heartworms themselves. Although somewhat expensive, this procedure can diagnose heartworms when other tests fail.

Treatment

There is some risk involved in treating dogs with heartworms, although fatalities are rare. In the past, the drug used to treat heartworms contained arsenic so toxic effects and reactions occurred somewhat frequently. Now a newer drug is available that does not have the toxic side effects of the old one. Today we are able to successfully treat more than 95% of dogs with heartworms.

We see some dogs with advanced heartworm disease. This means that the heartworms have been present long enough to cause substantial damage to the heart, lungs, blood vessels, kidneys, and liver. A few of these cases will be so far advanced that it will be safer to just treat the organ damage rather than risk treatment to kill the worms. Dogs in this condition are not likely to live more than a few weeks or months.

Treatment to kill adult worms: An injectable drug to kill adult heartworms is drug is given for two days. It kills the adult heartworms in the heart and adjacent vessels.

Complete rest is essential after treatment: The adult worms will die in a few days and then start to decompose. As they break up, they are carried to the lungs, where they lodge in the small blood vessels and are eventually reabsorbed by the body. This is a dangerous period, and it is absolutely essential that the dog be kept quiet and not be allowed to exercise for 1 month following treatment. The first week after the injections is very critical because the worms are dying. A cough can be noticeable for 7 to 8 weeks after treatment in many heavily infected dogs.

Prompt treatment is essential if the dog has a significant reaction in the weeks following the initial treatment, although such reactions are not common. If a dog shows loss of appetite, shortness of breath, severe coughing, coughing up blood, fever, and/or depression, you should notify us. Response to antibiotics, cage rest, and supportive care, such as intravenous fluids, is usually good in these cases.

Treatment to kill microfilaria: Approximately 1 month following treatment to kill the adults, the dog is returned to the hospital for administration of a drug to kill microfilaria. Your dog needs to stay in the hospital for the day. Seven to ten days later a test is performed to determine if microfilaria are present. If they have been all killed, the treatment is complete. If there are still some present in the blood, treatment for microfilaria is repeated.

In some cases, the heartworm infection is "occult," meaning that no microfilaria were present. In this case, a follow-up treatment at one month is not needed.

Other treatments: In dogs with severe heartworm disease, it may be necessary to treat them with antibiotics, special diets, diuretics to remove fluid accumulations, and drugs to improve heart function prior to treatment for the heartworms.

Dogs with severe heart disease may need lifetime treatment for the failing heart, even after the heartworms have been killed. This includes the use of diuretics, heart drugs, aspirin, and special low salt, low protein diets.

Response to treatment: Dog owners are usually pleasantly surprised at the change in their dog following treatment for heartworms, especially if the dog had been showing signs of heartworm disease. The dog has a renewed vigor and vitality, improved appetite, and weight gain.

Prevention

When a dog has been successfully treated for heartworms, you cannot sit back and relax because dogs can be reinfected. Therefore, it is essential to begin a heartworm prevention program. Three commonly available products for heartworm prevention are HeartGard*, Interceptor*, and Revolution*. Heartgard* and Interceptor* are chewable tablets that are given only once a month while Revolution* is a topical product that is also applied once monthly. All three products are very safe and very effective and one of these should be started immediately after treatment is completed. Read more...

The Facts of Life

The Facts of Life (Canine Version)

1.) Dogs have about 100 different facial expressions, most of them made with the ears.
2.) The common belief that dogs are color blind is false. Dogs can see color, but the color scheme they see is not the same as ours. They distinguish between blue, yellow, and gray, but probably do not see red or green.
3.) Every known dog except the Chow has a pink tongue- the Chow’s tongue is jet black.
4.) The expression “three dog night” originated with the Eskimos and means a very cold night- so cold that you have to bed down with three dogs to stay warm.
5.) At the end of the Beatles song “A Day In The Life”, an ultrasonic whistle, audible only to dogs, was recorded by Paul McCartney for his Shetland sheepdog.

To read the feline version hit the jump.

The Facts of Life (Feline Version)
1.) Cats can be either right-pawed or left-pawed.
2.) Cats respond most readily to names that end in an “ee” sound. And, they love to hear the sound of their own name and your voice, so talk to them often.
3.) Cats can see up to 120 feet away. Their peripheral vision is about 285 degrees.
4.) Cats are the only domestic animals that walk directly on the claws, not on their pads. This method of walking is called “digitigrade.”
5.) A cat’s sense of taste is keener than that of a dog.

Read more...

The Life And Times Of Your Cat

From kitten to senior citizen our cats live remarkable lives. Listed below are some normal behaviors and common health concerns for each of your cat’s life stage:

Birth to 1 year (Kitten)
Initially, while your kitten is just beginning to learn her way around, she may be playful, but will also most likely be very shy as she adjusts to her knew home. As she progresses through this life stage she will come out of her shell and become more playful, spunky, and adventurous. At approximately six months old, you should spay or neuter if you are not planning to breed your cat.

1 to 8 years (Prime)
Your young cat is in her prime. Remember your annual visits to the veterinarian as health issues such as obesity, dental disease, and heart disease may start to make their first appearance. Also be sure to have her checked for parasites regularly as she is a keen hunter at this stage.

8 to 12 years (Senior)
Your cat is now considered a senior and may begin to slow down, but her behavior shouldn't change much. Previous health issues may start to increase in severity and new ones may start to appear so it is important to continue your regular visits to your veterinarian. Cats in this stage of life have an increased risk of diabetes, kidney disease, high blood pressure, hyperthyroidism and cancer. Obesity can also be a major health issue for cats in this age range.

12+ years (Geriatric)
Your cat is entering old age. You may begin to notice some new health problems arise or an increase in severity of pre-existing ones. During this stage your cat will be at an even greater risk for all of the health issues listed in the previous stages. Your cat will also most likely move slower and may develop arthritis as her joints begin to stiffen. You may also notice a change in her temperament as she becomes more easily irritated at this stage.

Final Thoughts
Your cat is a great companion and loves you very much. That is why it is so important to recognize the milestones in your cat’s life so you can take the best possible care of her.

As with any health-related issue, whenever you have concerns about your cat, consult your veterinarian. He or she is familiar with your cat and her medical history and has the professional skill and knowledge to identify and treat whatever might be the problem. Read more...

The Seven Deadly Foods

It’s dinner time once again and as if by clockwork your dog starts circling the table looking for a free hand out. We may not think much about giving our dogs table scraps, after all what was good for us must surely be good for them, but we often forget just how different we really are from our beloved pet. Below is a list of seven everyday foods that could do your pooch more harm than good. Some are only trouble if given in large quantities while others can be deadly in any amount. Either way these tasty treats could lead to serious problems.

Avocado
Most commonly used as the main ingredient in guacamole, avocado includes a toxin called persin. While relatively harmless to humans (unless you are allergic) persin can cause vomiting and diarrhea in dogs when consumed in a large enough quantity. And not only does the fruit contain the toxin but so do the seeds, leaves, and bark from the tree.

Candy, Gum, Toothpaste, baked goods, and some diet foods
The products in question from the list above are those sweetened with xylitol. Xylitol is a naturally occuring sugar substitute often used in the food industry. If ingested it can potentially cause an increase in insulin, a drop in blood pressure, seizures, and possibly liver failure. Initial symptims may include vomiting, lethargy, and loss of coordination.

Chocolate
It’s common knowledge that chocolate is bad for dogs. But did you know the main culprit behind this deadly treat is called theobromine? A bitter alkaloid of the cacao plant, theobromine can be found in all forms of chocolate including white chocolate. Dark chocolate and unsweetened baking chocolate contain theobromine at it's highest conecntrations so should be avoided at all costs. Potential symptoms include vomiting, diarrhea and excessive thirst. If a case of severe poisoning is observed heart rhythm, tremors, seizures, and even possibly death may occur.

Fat Trimmings and Bones
It has been a long held belief that all a dog wants in life is a warm bed, a spare hand to throw a ball, and a good bone to chew on. However, bones may not be the great treat they appear to be. In general bones are a choking hazard and when chewed may splinter causing an obstruction or laceration of your dog’s digestive system. In addition all the fat we often leave attached to the bone can lead to furtrher health issues such as pancreatitis. So do your dog a favor and next time they look at you with those big brown eyes put that bone in the trash where it belongs and not in their dog bowl.

Grapes and Raisins
A show of hands, how many of you give your dog a grape every once in a while? It’s more common than you might think, after all it’s only a grape so what could possibly be the problem. The problem is grapes and raisins can potentially cause kidney failure in dogs. The reason for this is still unknown but the fact of the matter is you shouldn’t be handing out free grapes to your four legged friend. Early signs of poisoning can include vomiting and hyperactivity. If left unchecked within a day your dog may become lethargic and depressed.

Macadamia Nuts
In general no nut is a good nut when speaking in terms of your dog. However, macadamia nuts are surely one of the worst. As few as six nuts is it all it can take to make your dog ill. Symptoms include muscle tremors, weakness or paralysis of hind quarters, elevated body temperatures, and rapid heart rate. If chocolate is added to the mix the symptoms can be even worse.

Onions
Onions are toxic in all its forms whether it’s powdered, raw, cooked, and dehydrated. The problem with onions is that in a large enough quantity they can destroy red blood cells causing anemia. While a very tiny amount once in a while may be ok a large amount in one sitting or small amounts over a long period can be harmful. Symptoms of onion poisoning include vomiting, diarrhea, lack of appetite, dullness, and breathlessness.

If you suspect your pet has eaten any of the items on our list then be sure to check their mouth thoroughly and make sure nothing was swallowed. If you think your pet may have swallowed something contact your local veterinarian immediately and have the phone number for poison control on hand in case you are directed to give them a call. The phone number for the ASPCA Poison Control Center is 1-888-426-4435.
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Speedlinks: March 3, 2010

Your portal to the most interesting, absurd, and unbelievable animal stories in the news today.

What do "George" the great dane and a small horse have in common?  They are the same size.

Meet "Sockington".  He spends his days clearing up all those nagging questions you have about what your cat is actually thinking.
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