When Is A Swollen Belly An Emergency?

Dogs with any of these symptoms need to be taken to a vet immediately:

• Vomiting
• Hard, painful abdomen
• Collapse
• Severe lethargy
• Not eating

Now dive deeper…

The picture above shows what a dog’s normal body shape should be.

Could it just be fat? The answer is usually ‘no’. Overweight dogs are so common that they look normal to most people. Therefore, trust your instincts: if the stomach looks odd, it’s almost certainly not just fat.

For example, the pictured dog isn’t fat anywhere else, and the belly hangs down more than it should. Even though he seems well, he’s in a lot of trouble.

Causes Of An Enlarged Abdomen

There are many reasons why the stomach gets bigger than normal. I’ll classify them by the cause of enlargement and start with the most serious. There are two special cases in puppies near the end.

Gas: Bloat

Bloat or GDV occurs when the stomach suddenly twists and blocks the escape of gases. Gastric expansion follows, and without treatment dogs die a rapid and horrific death.

Affected dogs are usually large breeds with obvious distress and a hard, painful abdomen. If your dog is comfortable and eating or drinking, they don’t have bloat. You can read more about the causes and prevention of bloat here.

Sometimes a dog’s stomach swells up with gas for less serious reasons, like overeating. I saw one this week which happened with no obvious cause. These dogs need xrays to tell them apart from life-threatening cases of bloat, and to monitor the stomach size.

Pain: Peritonitis

Abdominal pain makes dogs hold their belly stiff and tight like a drum. We call this splinting. You should always treat this sign as an emergency.

The most common cause is pancreatitis, which you can read about at the link. However, this is indistinguishable without testing from other causes of inflammation or infection, such as:

• Intestinal obstruction from swallowing the wrong thing
• Ruptured or twisted bowel
• Gall bladder diseases
• Gunshot or stake injuries

Blood: Haemorrhage

Internal bleeding can cause the belly to look bigger, however it’s rarely the most obvious sign. These dogs are also usually weak, pale, lethargic or even collapsed.

There are two common causes of abdominal bleeding:

1. Eating rat poison stops the blood from clotting, and although there’s an antidote, most dog owners haven’t realised their dogs ate it until symptoms begin
2. Haemangiosarcoma is a tumour of the spleen whose first sign is often unexplained blood loss

It’s also very possible to have abdominal haemorrhage after any major surgery or injury. Obviously, whatever the reason, bleeding is always a critical emergency.

Urinary Tract Damage

Damage anywhere in the urinary tract can cause urine to leak into the abdomen. The most common reasons for this are bladder stones blocking the urethra, and car accidents.

Like with bleeding, the amount of fluid is mostly small, and other more obvious signs of illness are present, like lethargy, straining or pain.

Food: Overeating

A classic and sometimes serious cause of bloated stomachs is when a dog biscuit bag is left out while you’re not at home. Most dogs will binge on the kibble until they can’t eat any more, then the kibble starts to swell as it takes on water. These dogs often need the vet to induce vomiting to relieve the distress.

In puppies, abdominal distension after eating is quite normal. As long as they are bright and playful, and it goes down in a few hours, there’s nothing to worry about. However, the next cause also needs consideration…

Parasites: Worms

Intestinal worms are a very common and serious reason for a swollen stomach in a young puppy. Roundworms (pictured) often get large and numerous enough to swell the belly and block the passage of food.

Read all about preventing and treating intestinal worms here.

Fluid: Ascites

Many diseases cause the buildup of a clear fluid that we call a transudate. Most of these slowly worsen without any other major signs of illness. Examples might be:

1. Heart disease
2. Caval syndrome from heartworm
3. Portal vein obstruction from tumours
4. End stage liver disease
5. Certain widespread cancers
6. Protein-losing enteropathy
7. Protein-losing nephropathy

The first four happen because the blood pressure in abdominal vessels gets high enough that fluid leakage occurs. Number 5 is simply because fluid often escapes from tumours with a high surface area.

Numbers 6 and 7 are probably the most common. They happen when blood proteins are being lost through the gut or via kidney disease. This leads to a drop in plasma oncotic pressure, which causes fluid to leak from small vessels. The fluid will also often be present in the chest cavity.

Testing is essential to identify and treat the cause. Often all of the following are needed:

• History & physical exam
• Ballottment of the abdomen (percussing one side of the belly and feeling for a fluid wave on the other)
• Blood and urine tests
• Ultrasound exam
• Intestinal biopsy

The most common cause is inflammatory bowel disease as a consequence of protein-losing enteropathy. You can read about that here. As you can imagine, without treating the cause, drainage of the fluid is usually useless.

Fat: Hormonal Diseases

Even though fat deposition is unlikely, there are two diseases in which it is laid down in a way that can look like a swollen stomach. These are:

• Cushings disease, associated with an enlarged liver, pot belly, hair loss and excessive drinking
• Thyroid disease, associated with lethargy and unexplained weight gain 

You can read about tests and treatment for both diseases at the links.

Masses & Enlarged Organs

Sometimes a tumour in the abdomen can get so large that it causes the belly to noticeably bulge. These are usually slow-growing benign masses, otherwise they would have caused other signs earlier. Swelling can also occur when organs themselves become enlarged. Perhaps the most important are the liver and spleen. 

Diagnosis requires blood testing and an ultrasound exam. Even large masses can often be removed if there is no evidence of spread.

Uterus: Pregnancy & Pyometra

Lastly and very rarely I have seen owners of a female dog not be aware of a mating 5 to 6 weeks earlier. In older un-desexed females, a uterine infection called pyometra or reproductive tract cancer can also swell the abdomen in a similar way. 

These unplanned events should be a lot less common now that desexing has become compulsory in Adelaide.

I’ll end on a positive note. Despite some of the horrendous diseases mentioned here, most causes of abdominal enlargement that I see are the ones that can be treated, often with just a tablet. Therefore, don’t be frightened of getting the vet to take a look. It’s usually all for the better.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.

• A young, social dog with no other signs of illness is at low risk
• An older dog or any with lethargy or loss of appetite is higher risk
• Dogs with an elevated breathing rate should see a vet urgently

Now dive deeper…

Coughs in dogs are common enough that almost all of our dogs will have one at some time in their life. Some will be serious, others less so.

It’s also quite possible you will get the wrong advice. Our understanding of the causes of coughing has changed, especially for older dogs. It’s certainly not as simple as knowing whether it’s a wet or a dry cough. 

However, before we get to the causes, there’s one question we always need to ask ourselves…

Is It Even A Cough?

This might seem a strange thing to say, but trust me, it’s not. Most dogs that cough are also gagging and retching, making for a very confusing picture. Here are just three signs often mistaken for coughs:

• Reverse sneezing is a loud snorting or choking noise made in the back of the throat. If you’ve never seen it, I’ve put up a few videos here.
• Post-nasal drip occurs when thick mucous secretions from the nose or sinuses run over the back of the soft palate to the larynx. The clue is that these dogs are mostly snorting or sneezing. Find the causes of sneezing and nasal discharge here.
• Retching and vomiting often look like coughing in dogs. Perhaps the best way to tell is that vomiting dogs have usually also lost their appetite.

Odds-on your dog will miraculously stop coughing when they reach the vet. Therefore, the best way to put a smile on your vet’s face is to take a video with your smartphone. It won’t necessarily tell us what type of cough it is, but it should at least tell us which body system to investigate first.

So let’s say you’re confident what you see is a cough. Let’s look at why it might be happening.

Causes Of Coughing In Young Dogs

A simple way to get a rough idea of what might be wrong is the age of the dog. While (of course!) anyone can get anything, generally young and old dogs get different diseases. Add to that a good physical exam, possibly an X-ray and we’re usually in a good position to tell you what’s wrong. 

Causes of coughing in a young dog are mostly infections.

Kennel cough

Kennel cough or infectious laryngotracheitis is extremely common in social dogs (you can read a whole article on it here). Key points are:

• It’s acquired anywhere, but especially from dog parks
• It has an incubation period of around seven days
• Vaccination is good, but not perfect

Treatment of kennel cough is mostly via anti-inflammatories. By reducing the discomfort, the cough reflex gets a lot better and the poor doggies can sleep. We also use antibiotics and cough suppressants in selected cases.

Foreign material

Just like people, dogs can inhale solid objects into their airways. While anything can do it, we mostly see one of two scenarios:

1. Grass seeds can get stuck anywhere due to their spiky nature. We generally see them in the nasal passages but sometimes they get inhaled right into the lungs.
2. Food can be inhaled into the lungs, from where it causes aspiration pneumonia. Most of these dogs have something else wrong, like laryngeal paralysis or megaoesophagus but it’s also why we’re so careful about not giving anaesthetics unless the stomach is empty.

Aspiration pneumonia has a characteristic appearance on X-rays. Grass seeds are a lot harder to see and require us to be suspicious to go further. Therefore, it’s a good idea to let your vet know if there are a lot around at home.

Heartworm

Up to the late-1990s, heartworm was our most common cause of unexplained coughing. These dogs got very sick, and many died. With the advent of good heartworm prevention, this has become just a memory, but it’s still common in areas with poor levels of control. You can read more about our experiences with heartworm in Adelaide here. 

Bronchopneumonia

Infection of the lungs is a lot less common in dogs than people. That’s probably because dogs don’t get the human cold or flu, but also because gravity is on their side. It’s a lot easier to cough things up if your lungs are horizontal!

However, we do see occasional unexplained pneumonia. As long as we treat them promptly, these dogs should make a full recovery. 

Why Old Dogs Cough

Most of the reasons for an old dog coughing are the effect of ageing on the body. We’ll start with two common conditions that affect the cartilage.

Tracheal Collapse & Bronchomalacia

If you feel your windpipe it will no doubt be hard and inflexible. That’s just how it should be. Yet for unexplained reasons, the cartilage in many old dogs gets soft. Then, during the breathing cycle, the weakened cartilage is unable to maintain its normal shape.

If this happens in the windpipe, it often results in tracheal collapse. The usually round trachea becomes oval and can even collapse completely so that the sides touch. 

You can imagine how distressing and uncomfortable this is for the dog. Attempts to breathe only increase pressures and make the collapse worsen. Airway irritation stimulates a harsh cough that in turn adds further irritation. 

Excitement and neck pressure tend to make tracheal collapse worse. I really feel for these dogs. 

Bronchomalacia is the same process when it occurs in the smaller airways of the chest. The distinction is important as this cough is often confused with heart failure. 

Treatment for either problem is never easy. Surgery is rarely a realistic option, so we have to rely on juggling a combination of the following:

• Anti-inflammatories
• Weight loss
• Cough suppressants
• Bronchodilators

It’s almost never possible to stop the cough completely, but we can usually at least reduce distress and give comfort.

Cardiac disease

A heart problem can cause a cough in two ways. 

1. Pulmonary oedema causes fluid to accumulate in the lungs until it stimulates a cough reflex. We see this cough more commonly after lying down and especially at night. Often the dogs will also have an elevated respiratory rate (above 30 per minute) and cough up small amounts of white foam. 
2. Heart enlargement causes the airways above the heart to be compressed. This is especially likely if there is also bronchomalacia.

These days, most heart specialists think that ‘cardiac coughs’ are being over diagnosed. It’s vital that we don’t assume that just because a coughing dog has a heart murmur that the two are related. 

A dog with a heart problem, not just a murmur, will usually also have poor fitness and rapid breathing. At a bare minimum, we should at least do an X-ray to be more certain. Treatment is then via:

• Diuretics to reduce pulmonary oedema. 
• Drugs for heart disease to improve performance and reduce heart size. 
• Plus treatments for bronchomalacia (above) and bronchitis (below) if need be. 

Chronic bronchitis

Bronchitis is another disease that can affect the same animals. In fact, it’s not unusual for all three to have a role in an old dog’s cough.

Bronchitis responds best to either antibiotics, prednisolone or both. Despite the changes you might see on an X-ray, it often comes down to a ‘treatment trial’ to see what works.

Are you starting to get the idea that old coughing dogs are challenging?

Laryngeal paralysis

I’ve already mentioned laryngeal paralysis in the context of aspiration pneumonia but it’s really a disease of older dogs. These are usually larger breeds of dogs with characteristic raspy breathing that gets worse with exercise and warm temperatures. The treatment is surgical. 

Rare Causes Of Coughs

The last few I have almost never seen but are included for the sake of completeness. 

• Parasites are a rare cause of coughing in Australian dogs, but reasonably common in other parts of the world.*
• Eosinophilic pneumonitis is the closest thing we see to an allergy response. Strangely, we almost never see coughs from dust or smoke.
• Cancer in the chest can cause coughing but it mostly causes difficulty breathing.
• A dog that eats rat poison might cough from bleeding in the lungs.
• Some fungal infections are very common in certain places.
• Both the distemper and hepatitis viruses can cause coughing.

What To Give A Dog For A Cough

The use of cough suppressants without a diagnosis is never a good idea. In our desire to get rid of a cough it’s easy to forget that most coughs are doing something useful: clearing the lungs of material that shouldn’t be there.

Successful treatment is entirely about understanding the cause. The final thing to say about coughs is that it’s not really possible to tell them apart at home. Hopefully, I’ve given you an idea of what might be wrong, but you always need a vet to get a proper diagnosis. And it really matters to get it right, as I hope you can see.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.

*Four species of worm (Crenosoma, Oslerus, Capillaria, Angiostrongylus) can cause coughing in certain areas. 

1. Ask advice
2. Research it yourself

An amazing number of dog owners using option 2 will buy Sentinel Spectrum. One look at our chart of the flea and heartworm treatments for dogs and you’ll see why. It does ‘everything’.

Is it really as good as it looks? I’ll let you decide. In the process, you’re going to learn a whole lot about choosing the best product for your dog.

But I must warn you: this isn’t going to be fair. There’s a reason behind everything I say, but you’re getting my personal opinions.

What Is Sentinel Spectrum?

Sentinel Spectrum is a once-a-month flavoured tablet that prevents heartworm, fleas and intestinal worms in dogs. It is the most complete single product for these three groups of parasites. That’s why it’s deservedly popular. I like it too.

But…

Once you understand it you might, like me, think there are better solutions. It’s a case of ‘jack of all trades, master of none’. Let’s look at each of the things it does, and a few extra it doesn’t.

Sentinel’s Flea Control

Sentinel contains lufenuron, an insect growth regulator. It kills fleas in the egg by blocking their growth. That’s great for safety. Being the only non-insecticidal product for dogs is certainly an excellent drawcard.

However, not killing fleas isn’t always compatible with an active lifestyle. Your dog will undoubtedly pick up ‘travellers’ on the street, at the park, and even in your yard from stray cats. These fleas will live long, happy lives. So if you’re into flea welfare, Sentinel is the best. Personally, that’s not a group I’ll be joining anytime soon.

My Flea Control Choice

Modern treatments in the isoxazoline class are very safe and extremely fast in removing fleas. Like Sentinel, they’re also tablets so you don’t have any messy drug and solvent on the coat.

There are three. Simparica is my clear winner. I have seen no evidence of it being out-performed anywhere. Just yesterday I saw a dog that lives in the hills who has always had mite problems no matter what was used. Until this year, that is, thanks to Simparica. One very happy dog (and owner).

Bravecto has taken a lot of heat for suspected adverse reactions in dogs, which I think is unfair (even Simparica has had a side effect scare). However, it’s still wise to avoid longer-acting products if you can use shorter-acting products effectively.

Nexgard I have no strong opinion of. Towards the end of the month, it’s a bit slower to kill fleas and ticks than Simparica.

Hang on, did I just mention mites and ticks? That needs an explanation.

Is Sentinel a Mite & Tick Treatment?

No. Companies aren’t great at telling you what their products don’t cover. Here’s a list of the common mites and ticks of Aussie dogs, which is very similar to other countries.

• Ear mites
• Demodex mites
• Sarcoptic (mange) mites
• Paralysis tick (not present in Adelaide)
• Brown dog tick

The paralysis tick deserves a special mention. At one time, half of the patients in some vet hospitals in the eastern states had tick paralysis. It kills without treatment and is very expensive to manage.

Now a series of products capable of preventing tick paralysis properly have changed this picture forever. Today, most veterinary practices on the east coast would see fewer tick paralysis cases in a year that they formerly saw in a week. Those products are, once again, Simparica, Nexgard, Bravecto.

Why anyone living in a tick-prone area wouldn’t use these is a mystery to me. Even in boring old Adelaide, they will prevent all the mites in the list above, plus prevent paralysis ticks when travelling. Ear mites and Demodex are particularly common in puppies.

Sentinel’s Heartworm Control

Sentinel will kill heartworm larvae for one month after they are deposited by mosquitos. That’s the same as most heartworm preventatives on the market. Safe and effective.

However, if you read my history of heartworm in Adelaide you’ll see how we never had good control using monthly treatments alone. It’s not that they don’t work, it’s that we keep forgetting to give them. Me included. I used to remember it at 3 am and then forget it the next day.

My Heartworm Control Choice

That’s why we recommend that most dogs receive the annual ProHeart injection, containing moxidectin. It doesn’t cost much more and works for 12 months after each dose in adults.

Hang on, I hear you say, didn’t you just tell me that shorter-acting is better than long-acting? Yes, that’s still true, and I certainly support the reliable use of any monthly treatment. The three reasons I think this is an exception are:

1. Moxidectin is incredibly safe
2. The dose is low due to heartworm larvae being especially sensitive
3. Existing monthly treatments don’t work for most dog owners

Sentinel’s Intestinal Worm Control

Sentinel kills all the common intestinal worms in Adelaide dogs, including tapeworm. That makes it unique among heartworm treatments in 2018.

My concerns here are minor and easily ignored. I just don’t like worming dogs more than we need to. It’s a theoretical concern and there’s nothing to back up what I say. Except…

Studies in humans have shown the interesting link between allergy and being free of worms (reference below). It seems like the immune system needs something to keep it busy. In other words, it may be better that we pick up the odd worm than never have them at all.

My Worm Control Choice

Existing recommendations to give a worming tablet every 3 months probably achieve a good balance. The life cycle for most worms is around two weeks. Dogs are likely to pick up worms at the park but never get enough to harm them.

When Sentinel Is Great

So now that I’ve picked on poor Sentinel Spectrum, let’s give it the chance to defend itself. It does a good job of heartworm and intestinal worm control if used correctly. It’s perfectly fine for fleas if dogs aren’t too social. Those fleas that are picked up won’t breed in the house.

It has one other distinct advantage that should not be ignored: price. For what it does, it stands out as the cheapest option. In a world where dog health depends on an owners’ financial state, this is also important.

So if you’ve chosen Sentinel, don’t feel that there’s anything wrong with that. I picked it as an example but I could have done the same with most products. But I hope you can see how a tailored approach designed by your vet can be better.

Further Reading

Natural flea remedies | Australian flea & heartworm treatments

Feary J, Britton J, Leonardi-Bee J. Atopy and current intestinal parasite
infection: a systematic review and meta-analysis. Allergy.
2011;66:569-578.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

Compare this with the 1980s and 1990s. It’s hard to find a dog owner from that time who didn’t know a dog that died from heartworm in Adelaide.

Like most vets of my age I’ve been unlucky to diagnose and treat a lot of cases of heartworm. I hope it will never happen again, but I’ve got good reasons to be worried. This story is typical:

• Several years ago, before we settled on the DV foster care program, I was looking for a charitable outlet for Walkerville Vet. I contacted a well-known dog rescue organisation, and offered to help by providing free desexing, vaccines, heartworm prevention and microchips.
• We arranged a meeting and it all went well until the subject of heartworm came up. I was told that they didn’t believe heartworm was a problem, and they didn’t use prevention. In fact, they wouldn’t use or recommend prevention even though I was offering it for free!
• In the end, I had to withdraw my offer; they weren’t going to budge and I wasn’t going to do a half-baked job.

Wow do we have short memories; the folk memory of heartworm is already disappearing, even though the disease hasn’t. This happens every time we get success in preventing a disease. Take these three for example:

• Polio: my father was expected to never walk again
• Diphtheria: my grandmother carried a tracheostomy scar for life
• Distemper: my parents as young vets saw this kill more dogs than anything else (read more about distemper here)

Is Heartworm In Adelaide?

Yes, but it wasn’t always the case. When I was a child visiting my NSW relatives, I remember them giving heartworm prevention even though we didn’t in SA. It seems that sometime in the 1970s South Australian dogs began to get infected.

We suspect it started when people started moving around more for work. In moving to SA they would of course bring the family dog. An infected dog would then act as a reservoir for infecting other dogs.

Another theory is that it spread via the Riverland. Regardless, by the 1970s, Adelaide researchers using greyhounds were finding it in some dogs at post mortem, and by the 1980s vets were seeing disease in pet dogs. By the 1990s it was a big problem.

Prevention and treatment of heartworm have since been a big success. Follow the link to learn more about heartworm and see a creepy sight we regularly saw down our microscope.

Is Heartworm Prevention Necessary?

So if heartworm disease is now rare, why do you still need to use prevention? There are two good reasons:

• Dogs with heartworm are still found throughout Adelaide. If one lives within the range of a mosquito, your dog will become infected if not protected.
• The concept of ‘herd immunity’

What is Herd Immunity?

My best analogy is a bushfire. For a spot fire to spread there needs to be enough dry fuel around to keep the fire moving.

If only some fuel is dry, sparks will sometimes land and catch fire, and sometimes not, and the fire will gradually die out.

For heartworm in one dog to spread, there need to be enough dogs not on prevention within mosquito range to keep the disease spreading. If the mosquitoes bite mostly protected dogs, like sparks landing on damp grass, the disease will peter out.

Herd immunity for heartworm depends on:

• The population density of dogs
• The percent of dogs protected

That’s why the occasional dog not on heartworm prevention (or the occasional unvaccinated dog) stays well; herd immunity is how these at-risk dogs still remain protected.

“Herd immunity is vulnerable to the free rider problem. Individuals who lack immunity, primarily those who choose not to vaccinate, free ride off the herd immunity created by those who are immune. As the number of free riders in a population increases, outbreaks of preventable diseases become more common and more severe. … If large numbers of people in a community free ride, herd immunity in that community is lost.” https://en.wikipedia.org/wiki/Herd_immunity

What happens next all depends on dog owners. I’m pleased to say that our clients almost 100% follow our recommendations. It’s up to us to keep levels of protection high enough to never let heartworm spread again.

What about cats? It’s complicated. Read about the heartworm in cats here.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

The Nobel Prize in Medicine is awarded for advances in human health. This year’s winners waited a long time for recognition; if dogs could vote, it would never have taken so long. The drug that saved generations of their lives went on to fight a major cause of human suffering.

Back in the 70s a group of researchers were looking for new treatments for parasitic diseases of animals. They isolated a bacterium from near a Japanese golf course which had a powerful effect on worms without harming the host animal.

Development and testing produced the drug called ivermectin which quickly became the most effective, broadspectrum antiparasitic drug ever developed. It safely treated a wide range of internal and external parasites in all animals from pets to livestock.

In 1989 Heartgard was registered in South Australia as the first monthly heartworm prevention for dogs. Owing to the extreme sensitivity of heartworm larvae to low doses of the drug, rates of infection rapidly reduced. Prior to this the only prevention was an unreliable daily tablet and heartworm disease was widespread.

However, there were still problems. Treatment rates were too low, and those that were treated often didn’t get the full 12 doses each year. We continued to see a lot of heartworm disease in Adelaide.

Then there was the problem with toxicity. While ivermectin is very safe for most, dogs with a defective MDR1 gene sickened from normal doses. This mutation is very common in collie-type breeds*.

New avermectins were developed with proven safety in collie dogs: selamectin (Revolution) as a spot-on version, and moxidectin (ProHeart) as another monthly tablet.

In 2000, Proheart SR12 Injection was released in Adelaide as the first once-a-year heartworm prevention. That same year, we started turning the tide against heartworm. I don’t believe the timing is a coincidence; we all had trouble remembering to give doses and buy new boxes. Here was the solution.

And now the human link. Sometime after the development of ivermectin for animal diseases, several people realised it could and should be just as effective in human parasitic diseases. In particular, two horrible and widespread African diseases called onchocerciasis (river blindness) and lymphatic filariasis.

It was discovered that just one ivermectin tablet per year was enough to prevent these diseases. A program was developed and Merck & Co (later MSD) agreed to make and distribute the drug to affected countries free of charge. I have no doubt this generosity was only possible thanks to the runaway success of ivermectin in animal health.

Satoshi Ōmura and William C. Campbell have just been awarded the 2015 Nobel for their discovery of the avermectin class of parasite treatments (Youyou Tu was also honoured for her discovery of artemisinin). Dogs and other animals everywhere thank you.

Their story shows not just how advances in animal health can improve human lives, but also the wealth of new drugs that might be still waiting out there beyond the golf course.

* Dog breeds reported to have the MDR1 gene mutation include Australian Shepherd, Border collie, Collie, English shepherd, Longhaired Whippet, Old English Sheepdog, Shetland Sheepdog (Sheltie), Rough Collie, Smooth Collie, German Shepherd, American White Shepherd.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

Each time it happened the scenario was remarkably similar: all of a sudden a cat would be rushed down to us in severe respiratory distress. It was horrible to watch these cats as they struggled for each breath and became more and more frantic. X-rays showed their lungs to be ‘whited out’ with pulmonary oedema, or fluid on the lungs. Almost always, nothing could save them. We would put them on 100% oxygen, administer diuretics, cortisone, bronchodilators, adrenalin but they usually died quickly.

This was all very strange but the strangest thing was that these cats had often seemed perfectly fine only minutes before this happened.

I still can’t say with certainty what was happening but here are three reasons I think it was feline heartworm disease:

• We were in the middle of the worst heartworm epidemic in dogs at the time
• These strange events stopped when we got the disease under control in dogs
• The symptoms of heartworm in cats were later found to be exactly the same (read about the symptoms of heartworm in dogs here).

At the time, the fact that cats got heartworm was well-known, but the symptoms were not well understood. We didn’t even think of heartworm at the time, but of course there was never going to be any way to save these cats even if we did.

What we know now is:

• Heartworm is a disease originating in dogs which can affect cats and ferrets.
• When it does, it is seen at roughly 10% of the rate at which the dogs get it.
• When it infects a non-typical host it causes severe and rapid disease (like Ebola does in humans).
• The symptoms are usually of anaphylaxis which is a severe immune reaction. In cats this usually causes fatal pulmonary oedema.

My personal opinion is that although many more dogs than cats got heartworm at the time (probably over 10%), more cats died than dogs. We’ll never know because they were not able to be tested at the time. Many dogs survived due to attentive owners, and we treated a lot successfully. Heartworm infection in cats may have been rarer, but the consequences were rapid and severe. And I dread that many more cats died when no one was watching.

So to the big question: should you use heartworm prevention for your cat? My answer is yes. Why?

• Two good flea controls include heartworm protection without having to spend a lot more.
• The disease may be uncommon in cats, but the consequences are terrible.
• Prevention is safe and easy to apply. Read more at Parasite control for cats
• The is no approved treatment once a cat acquires heartworm.

You will never hear me telling you it is necessary, or that you are neglectful for not using heartwormers in cats. The way most people decide what to do is quite lovely; they ask me what I use. I always told them my cat got a dose of Revolution every month.

One of the advantages of getting older (yes, there are good things!) is being able to look back to when things were different to today. We’ve come a long way as vets in pushing back the effects of distemper, nutritional disease, feline enteritis, parvovirus, mange, and most recently heartworm.

All of these diseases are not beaten, but with proper vigilance our pets should never experience them again. The danger is now in relaxing our guard or listening to cynics who say these protections are unnecessary.

To those who say vets’ advice is motivated by money, I would ask you to do one thing for me. The next time the AVA Annual Conference is in your town, go down to watch the delegates milling around between lectures. You’ll see young and old faces, mostly female these days, all carrying the same expression of earnest thirst for knowledge. If you eavesdrop a conversation, it will almost always be about a patient they are struggling to treat, of something they have just learnt. A few will be bragging about some rare disease they diagnosed or new technique they’ve mastered. No one is talking money and they’ve all spent a lot of it just to be there.

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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.