Clinical signs will depend on the level of worm burden. Acute symptoms can be sudden death, anorexia, weakness, breathing difficulties, ascites (fluid filled abdomen), anaemia. More chronic signs tend to result from inflammation caused by the migration of the microfilaria including coughing, respiratory distress, anorexia or vomiting. Diagnosis of heartworm can involve microscopic examination of blood, ultrasound of the heart, with blood tests available to detect female worm proteins or antibodies to the worm in the blood stream. Large worm burdens are best treated surgically. Where surgery is not available medical treatment is possible, however some of the drugs used are not licensed in the UK and require a special import license to obtain them from Europe. Treatment of heartworm carries a risk of blood clot formation, which in itself can be life threatening. Prevention of heartworm involves use of mosquito repellents; reducing potential exposure to mosquito’s by using mosquito nets and avoiding walking dogs when mosquitos are most active (dawn and dusk); regular prophylactic wormer effective against microfilaria.
Dirofilaria repens
A similar worm to D.immitis, D.repens is less pathogenic with adult worms living in the skin of cats and dogs. Like heartworm, D.repens is transmitted via the bite of a mosquito. The worm can complete it’s lifecycle at lower temperatures than heartworm and so is widely distributed in Europe. Infected animals can present with conjunctivitis and/or skin nodules. Treatment involves surgical removal of nodules or treatment with moxidectin/imidacloprid spot on, which can also be used for prevention alongside mosquito repellents. D.repens is a zoonosis causing conjunctivitis in infected people.
Infected dogs may present with sneezing due to nasal irritation, sometimes sneezing out the adult parasite, or gagging. Diagnosis can be achieved by visualising the worm using endoscopy or testing for eggs in nasal secretions or faeces. Treatment involves endoscopic guided removal of the worms and/or treatment with an anti-parasitide. L.serrata is a zoonotic disease, humans are infected through eating raw or undercooked offal, or via ingestion of eggs from the environment or nasal discharge of an infected dog. Infection in humans can lead to inflammation of the nose and throat, a blocked nose and pain, larvae can sometimes migrate into the front of the eye.
For further information about these exotic worms and other disease risks in travelling pets the ESCAPP (European Scientific Counsel Companion Animal Parasites) website offers an invaluable resource.
- Increased hunger, blood glucose is unable to enter the cells of the body, which is equivalent to the being in a state of starvation, the body sends hunger signals resulting in an increase appetite.
- Weight loss, despite an increased food intake the body is unable to utilise the energy from the food so it breaks down body fat to produce ketones as a source of energy.
As a general rule if a pet is unwell, particularly if they are inappetant or vomiting then it is recommended to give half the normal dose of insulin and/or contact your veterinary surgery for advice.
Regular feeding is essential, if your pet’s diet is varied their response to the insulin can be very unpredictable and can make it difficult to achieve stable diabetic control. Dogs should be fed twice a day around the time of their insulin injections, whilst cats often do better on ad lib feeding.
Type 2 diabetics – cats, though they do not have an overall lack of insulin, often insulin is still needed to help overcome the resistance. The same applies as with type 1 diabetics often twice daily injections are required. Obesity has a direct link with increased insulin resistance and so an appropriate diet and looking to keep weight under-control is an essential part of managing the disease. A high protein diet is recommended, and can help stabilise cats with diabetes, unless the cat is suffering a concurrent illness, such as chronic kidney disease, where such a diet would be contraindicated. For some cats with mild diabetes such a diet can on occasion be enough to achieve remission without the need for insulin. For some patients reducing body weight will reduce their insulin resistance and they may achieve remission, where further insulin therapy is not required. For this reason, they need to be monitored carefully to ensure we are treating them appropriately. Some cats who achieve remission will subsequently re-develop diabetes and need to restart treatment.
- Weakness, cats with diabetes can develop nerve damage.
- Urinary tract infections (UTIs), dogs and cats with diabetes have increased susceptibility to UTIs. Pets with UTIs generally present with increased urination with straining, the urine may appear cloudy or contain blood and have a strong odour. Diabetic control may destabilise so it is important to get infections treated promptly.
- Pancreatitis, inflammation of the pancreas can be both a cause or consequence of diabetes. Dogs and cats with pancreatitis typically go off food Dogs may have vomiting, abdominal pain is common, some cases will also develop diarrhoea. A previously well controlled diabetic can become temporarily destabilised when suffering concurrent pancreatitis. Pets with pancreatitis should receive prompt treatment.
- Hypoglycaemia -Giving too much insulin can cause the blood glucose level to drop dangerously low, it can lead to a pet having a potentially life-threatening hypoglycaemic episode. Animals with hypoglycaemia can present with lethargy, collapse, tremoring which in severe cases lead to seizures or coma. If you are concerned your dog/cat may be having a hypoglycaemic episode we advise you put something very sugary, such as syrup, honey or jam, on your pet’s gums (if your pet is seizuring do not put your fingers in their mouth as you could get bitten, in this case the syrup should be dropped into the animal's mouth from a safe distance). Once the syrup has been administered you should phone your veterinary surgery immediately.
For cats, provided they take to injections well, stick to a good diet and manage to keep their weight down, most will lead long and relatively normal lives. Sadly, cats who have an underlying disease condition triggering the diabetes are often much harder to stabilise.
If you are concerned your pet may be showing symptoms consistent with diabetes please take them to your vet for a check up, if possible taking a fresh urine sample with you.