Smorgasbord Pet Health – Mosquito season and the dangers of Heartworm in dogs by Sally Cronin

We don’t have a problem usually with mosquitos in Ireland as they are not keen on the rain either and prefer a warmer and more humid climate. We did have a problem with them in Spain even in the mountains that tended to be cooler. One of the methods we used to keep the numbers down was to allow the swallows to return each year from Africa to their nests, even the ones in the garage which we abandoned to them to prevent the cars being peppered with poop.

They fed on the mosquitos and it was worth the minor inconvenience. They made a wonderful addition to the garden birds and they were highly entertaining too.

Image by Gabriela Piwowarska from Pixabay

Anywhere in the world that has a mosquito problem can potentially be very dangerous for your cat or dog. If you have not already done so please ask the advice of your vet about any risks in your area. For those of us still in the cold part of the year it is a good time to think about this before the summer.

Heartworm is a worldwide problem for both dogs and cats but it is a particular issue in countries that have a mosquito problem as well.

It is a serious and potentially fatal condition caused by parasitic worms living in the right side of the heart and pulmonary arteries in dogs and cats. They can be found in other parts of the body but it is rare. The heartworm belongs to the roundworm family and is known as Dirofilaria immitis. These particular worms are long lived, grow up to 14 inches in length and can survive for five years and whilst living in the heart of the animal, the females can reproduce millions of offspring called microfilaria. These live in the bloodstream, hiding out in the small blood vessels and as they are unable to mature in the dog or cat they have to rely on a mosquito to bite the animal so that they can grow to adulthood.

How is the disease spread?

The female mosquito bites the dog or cat and ingests the microfilaria during the process. The young worm stays in the body of the mosquito for around 14 days before returning to the mouth. The next time the mosquito bites an animal the microfilaria, which is now infective, is passed into the bloodstream of the dog or cat where it matures over a three to six month period making its way to the heart where it begins the cycle again. The heart is the organ that is most affected by the worm in dogs, but in cats it tends to be the lungs.

The condition is not passed between animals, as it always requires the presence of the mosquito to complete the cycle. This means that particular care should be taken with animals in the appropriate mosquito months and when night-time temperatures are above a certain level. Symptoms can be slow to appear and most dogs are diagnosed between 4 years and 8 years old.

How do the heartworms affect the dog?

As with hardening of the arteries in humans the worms will begin to clog the major blood vessels feeding the heart and also the cavities in the heart itself. This causes a problem with the valves within the muscle leading to insufficient blood flow. This of course affects the blood flow to other organs and systems in the body leading to damage and eventual failure.

The problem with the slow diagnosis of the problem is that the amount of damage to the animal is already quite advanced to organs such as the liver, lungs and kidneys. A dog can develop cirrhosis causing jaundice and anaemia and the damage to the kidneys allows poisons to accumulate throughout the animal.

The symptoms are likely to be a soft continuous cough, shortness of breath, weakness, weight loss, nervousness, lack of energy and stamina. A dog might collapse after exercise as blood flow and therefore oxygen is restricted to the brain. In advanced stages the abdomen and the legs might swell with fluid retention as the body struggles to function with damaged kidneys and liver.

The young heartworms that are circulating in the blood stream can also cause problems as they block the smaller blood vessels. Tissue cells that are being supplied by these blood vessels are therefore going to suffer from the effects and become damaged.

How can you avoid infection?

The biggest danger in countries with mosquitoes in this day and age is not in the home where we tend to use repellents but outside at night if the dog is left in the garden for extended periods of time when the temperature is over a certain level.

In the height of summer only take your dog out for a brief walk last thing at night and keep him indoors after dark. For cats it is more difficult to contain them but the same principal should apply.

Whilst I tend to favour alternative and natural products for both humans and pets there are times when you may need to be pragmatic and adopt stronger measures. There are a number of repellent collars on the market for cats and dogs. Look for a high quality, long-life collar that helps protect against fleas, ticks and mosquito bites and it is well worth your dog and cat wearing all year in certain climates where mosquitos are consisently at high levels..

There are tablets that your pet can take on a daily or monthly basis to prevent infection and you would need to see your vet to get the best advice. Again I tend towards the more natural products on the market.

Natural remedies that may help to protect your pet from mosquitos

The key to finding a preventative is to establish what the parasite finds repulsive! For example mosquitos, like most of us find that neat lemon juice is bitter and will avoid. Whilst you can apply lemon juice topically in a number of ways, you can also encourage them to ingest lemon if you start them young enough.

There are a number of ways to prepare a topical treatment and here is one that I have used. At the height of the mosquito season though I did sometimes resort to a stronger measure in the form of a collar but always tried to use for as short a time as possible because of the toxic nature of the chemicals they contain.


• 6 lemons or you can combine lemons and grapefruit
• 1 litre of water
• 1 spray bottle

• Cut the fruit in half;
• Place fruit and water in a pot and bring to the boil, simmer for 20 minutes then allow to stand in the water until cool.
• Strain to remove any solids.
• Pour into a spray bottle.
• Generously spray your dog or cat’s body fur including underneath and up their legs to the underside.Avoid the face and eyes.
• Spray some of the liquid into your palm and apply carefully to the tips of your pet’s ears and around their next and face avoiding the eyes.
• If your dog is outside for longer than an hour at a time repeat during the day especially before letting them out at dusk onwards.

What should you do if you are concerned your pet may be infected with heartworm?

One of the major problems with heartworm is that it can take six months for the disease to develop.

The disease is also hard to diagnose as your pet may not show any outward signs in the early stages apart from a slight and persistent cough. This develops further in the next stages to lethargy and an unwillingness to exercise, followed in the last stages with heart failure.

Dogs in particular are wary of showing pain and vulnerability so if you live in high risk areas you need to keep a keen eye on your dog’s general health.

If you are concerned that your pet might be suffering from heartworm then take them to the vet straightaway. There are a number of tests that they can perform to determine if your animal has the problem ranging from blood tests for the adults and microfilaria, x-rays and electrocardiograms.

There are various treatments, the main one being injections with a drug containing arsenic, which of course does have its drawbacks especially if the dog is already weakened by the infection.

About a month after treatment for adult heartworms the dog must then undergo a treatment for the young microfilaria and this treatment will be repeated until all blood tests are clear.

After treatment the animal will need rest and a great deal of care during its recovery and if there has been extensive damage to major organs there is a likelihood of poor health for the rest of their lives.

Nutritional support for a pet with heartworm

I am not a huge fan of dried food, even the most expensive and acclaimed. Dogs and cats are carnivores and will also eat some vegetables and greens, like us their bodies were never designed to extract nutrients from dry biscuits effectively. I am also not a fan of the animal testing that is conducted by some pet food manufacturers in their efforts to measure their food’s effect on the body.

I have always made my own dog food using Basmati rice, vegetables and cheap cuts of meat, fish and poultry from the butcher. I have also used fruit such as cranberries which are great for a pet’s urinary tract and immune system.

I also have used a drop of lemon juice oil (two tablespoons of olive oil and the rind of two lemons on a low power in the microwave for 5 minutes. Allow to stand then strain into a glass storage bottle) and add to drinking water. It is a good idea to start this when the pet is young as they soon get used to it.

As with humans, healthy fats are essential in supporting the pet on a daily basis and particularly when they are recovering from illness. Particularly important are the Omega Fatty acids.. Omega 3 especially and this is easily combined with pet food in the form of flaxseed or cod liver oil capsules. I also used to give Sam a small amount of extra virgin oil or coconut oil with his meals

©2021 Sally Cronin

I am a qualified nutritional therapist with twenty-three years experience working with clients in Ireland and the UK as well as being a health consultant on radio in Spain. Although I write a lot of fiction, I actually wrote my first two books on health, the first one, Size Matters, a weight loss programme 20 years ago, based on my own weight loss of 154lbs. My first clinic was in Ireland, the Cronin Diet Advisory Centre and my second book, Just Food for Health was written as my client’s workbook. Since then I have written a men’s health manual, and anti-aging programme, articles for magazines and posts here on Smorgasbord.

If you would like to browse my health books and fiction you can find them here: Sally’s books and reviews

Thank you for dropping in today and your feedback and questions are very welcome.. thanks Sally.


26 thoughts on “Smorgasbord Pet Health – Mosquito season and the dangers of Heartworm in dogs by Sally Cronin

  1. I honestly never before had heard about heartworms. Maybe here its “Bavarian Siberia”, and mosquitos would be frozen instantely. Lol But with the climatic change we could get this problems too. Thank you for sharing preventive methods, Sally! xx Michael

    Liked by 1 person

  2. Thanks for the information. While I’d do anything for our dog, each trip to the vet costs an arm and a leg. Nice that there are some natural remedies.

    Liked by 1 person

    • It has become a multi-billion pound business and once the insurance companies get involved even worse.. They complain about the number of dogs that are surrendered to sanctuaries but particularly for elderly owners on a fixed income that benefit so much for owning a pet, the cost is prohibitive. Going the way of human medicine..xx

      Liked by 1 person

  3. Pingback: Smorgasbord Blog Magazine – Weekly Round Up – June 20th – 26th 2021 – Helen Reddy, Short stories, PR for Authors, Pet Health, Book Reviews, Funnies and much more. | Smorgasbord Blog Magazine

I would be delighted to receive your feedback (by commenting, you agree to Wordpress collecting your name, email address and URL) Thanks Sally

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.