Heartworm Disease Trivia Quiz

Answer: Dirofilaria immitis

The name Dirofilaria comes from the Latin words "dirus", meaning fearful, and flium, meaning thread. The etymology of immitis is not mild, so when you put them together you get a fearful not mild thread! Sounds like a Dr. Who nemesis to me... The Dirofilaria genus consists of parasitic roundworms that are small and threadlike.

While very small in diameter, the adult immitis worms can grow up to a foot (30 cm) in length. The adult worms are able to produce thousands of live young, called microfilariae, each day.

Answer: True

Prevention is important and is much safer than putting your pet through the treatment. A monthly dose of ivermectin helps protect the pet from being infected with heartworms. It is critically important to give the dose within 42 days of each other to kill the larvae when they are vulnerable.

The larvae require at least a two-week temperature of 80 degrees Fahrenheit (27 degrees Celsius) to develop making summer and fall a more common time for host infestation but larvae can survive in a dormant state until the opportunity arises.

Answer: Birds

Heartworms only live between mosquitoes and mammals, so a pet bird would be safe from infection. The most common animal is dogs, but many species of animals can become infected including humans. Dogs are the preferred host of heartworms and, if left untreated, can live in canines for up to seven years. Cats are less ideal hosts as the heartworm can't reach adulthood in felines, but infestations can still be deadly. Human infestations are very rare with the human body not being a good host for the worms.

In humans, the larvae eventually die off and typically are left untreated. The heartworms cannot reach adulthood in humans.

Answer: Mosquito bite

The live young of the heartworm, called microfilariae, migrate towards the skin of the host. A mosquito that bites the host will take in the microfilariae where they will go through the next two stages of development. The mosquito is a critical step in the lifecycle and the only way the heartworms can be introduced into a new host.

The life cycle within the mosquito requires about 20 days at which point the larvae will be injected into the next victim of the mosquito's bite. Once in a new host, larvae at this stage are six months away from being a full-grown adult heartworm.

Answer: Blood test

There are two types of blood tests - one that checks for microfilaria in the blood and another, called the occult test, which checks for adults in the heart. In dogs, the blood tests measure microfilaria, which will not appear until adult heartworms are able to produce them. From the time of the original mosquito bite the life cycle of the worm takes about half a year before microfilariae are born and thus can be measured.

In cats, the blood test relies on finding antibodies to the heartworm larvae and is less reliable. To be fully conclusive, an x-ray must be taken to confirm the larvae's presence.

Answer: A dry cough and breathing difficulties

As the worms grow in the heart, they can migrate to the lungs. Usually, a dry cough is the first sign. As the disease progresses, the dog will have a reluctance to exercise and becomes fatigued easily. Infected dogs may also eat less and lose weight. If the disease progresses long enough, surgery becomes the only option. Even if heartworms are completely removed from the dog's body, there can still be lingering damage caused by the worms.

Answer: Rest

The drug Immiticide contains arsenic that kills the adult worms. Despite containing arsenic, it is relatively safe for the dog with few side effects. It is critical that the pet rests for at least 2 to 3 weeks, so the animal's body can absorb the dead worms. If the pet becomes active, a dead worm could break off and lodge in the lung causing a potentially fatal embolism in the dog's lung.

Answer: False

The microfilaria must go through the mosquito to complete the life cycle. So, thankfully, the recipient dog would be safe from an infected transfusion. In most cases, the microfilaria that might be present in the blood would die off in the new host, though theoretically, a mosquito could take in a transfused microfilaria.

Answer: No

Unfortunately, for felines, there is not a good treatment option for an active infestation. Unlike dogs, heartworms cannot fully mature into adults within a cat and do not live in the circulatory system. Instead, they infest various parts of the body.

As a result, sudden death is possible for the cat if the worm destroys a vital area. So prevention is critical for cats. Even indoor cats can get heartworms as long as mosquitoes can bite them.

Answer: Yes

As good as the preventatives are for heartworms, it is still possible for heartworms to take up residence in our pets. For this reason, it is important to have your pet annually tested at the vet to make sure they are clear of infection. It is critical to give your pet the heartworm medication on time each month to reduce their risk. There are over 1 million cases of heartworms each year in the USA alone. The disease reaches around the globe wherever mosquito carriers are out for blood.