Bacterial Diseases in Dogs

bacterial diseases in dogs

They are extremely tiny and absolutely everywhere – bacteria! They lurk outside in nature, in forests, in meadows and in fields. Many of them are completely harmless to our four-legged friends, but some bacteria can lead to serious diseases in our dogs. Here are five known bacterial infections and their treatment options.

Bacteria play an important role in the body of our dogs. In the intestine, they provide a balanced digestive intestinal flora, and they form a similar healthy flora on the skin. Unfortunately, not all bacteria are so harmless and useful. Some can even be extremely dangerous, for our dogs as well as for us humans – for example, leptospirosis a so-called zoonosis, which can be transmitted from animals to humans vice versa. The signs, treatment and prevention of some bacterial diseases are described below.

1. Borreliosis (Lyme disease)

The borreliosis bacteria are transmitted through ticks, which stalk our dogs when out and about in forests, fields or tall grass. Depending on the region, the risk of being bitten by an infected tick varies. In northern latitudes, Lyme disease is one of the most common dog diseases transmitted by ticks. Of course, not every tick bite automatically leads to the onset of the disease, but once the dog is infected, the illness is sadly often too far developed.


Compared with other bacterial diseases, borreliosis can often have an effect on our dogs’ immune systems as late as several weeks after entry. Another issue with this disease is that the symptoms are fairly broad and unspecific, meaning that cannot automatically be attributed to Lyme disease. They include, for example, fever, fatigue and loss of appetite. The round redness that appears in humans does not always appear in dogs, or is not visible due to the coat. Later on in the disease, it is not uncommon for joints to become painfully inflamed, which can be clearly visible after getting up. If your dog is lame, less agile or exhausted, consult your veterinarian.


The sooner you recognise the symptoms as Lyme disease and get them treated, the higher your dog’s chances of recovery. If a test has confirmed borreliosis infection, a special antibiotic will be prescribed, although it is not always successful, particularly in advanced cases. It can result in chronic damage, ranging from severe to fatal, in vital organs such as the kidneys or heart.


Thankfully, there is a lot you can do to help protect your dog against ticks and stop serious illnesses in plenty of time. If you live in high-risk areas, vaccination of your dog against Lyme disease may be recommended. Ask your veterinarian for advice and weigh up the pros and cons of having the vaccine. Special sprays are also available, as well as collars, which can help minimise the risk of a tick bite.

In addition, it is advisable to search your dog after every walk, especially if you have been near forests or meadows. Ticks do not bite immediately, so if you catch them early they should be clearly visible on the surface of the coat and can be easily removed with a cloth. Once a tick has bitten, you will generally find it on the head, neck, ears, between the toes, on the stomach or on the inner thigh. The tick must be completely levered out using a special tick removal tool and should under no circumstances be twisted or squeezed, as this can cause dangerous bacteria to enter into your dog’s bloodstream.

2. Colibacillosis

The cause of colibacillosis is being infected with the so-called coli bacteria, for example Escherichia coli (E-coli) or enterococci. For a long time, people were primarily the ones affected by these germs, but dogs are becoming more and more frequently affected by E-coli. The bacteria can enter through licking of the anus or through contaminated water, and can lead to serious intestinal or urinary tract infections.


Painful urinary tract infections, diarrhoea and vomiting can all be a consequence of this bacteria. Puppies are particularly at risk, as they have not yet built up a sufficient protective barrier against such pathogens. In rare cases, infection with coli-form bacteria can lead to life-threatening meningitis in puppies.


The signs of infection are not always easy to spot. Gastrointestinal complaints are also not always directly associated with colibacillosis. If the diarrhoea lasts longer than expected and there are episodes of fever at the same time, you should immediately take your dog to the vet. Only a veterinarian can give a reliable diagnosis and initiate important treatment measures. In general, this will consist of treatment with antibiotics. A urine or stool examination will take place, so that an accurate resistance test – an “antiobiogram”- can be created, providing information on the number and resistance levels of the germs, helping your vet to select a suitable antibiotic. Depending on the findings, the treatment should last from anywhere between 10 days to 3 weeks.


Unlike humans, dogs cannot protect themselves against these dangerous pathogens by washing their hands. Nevertheless, hygiene plays a key roe, so you should keep food bowls and sleeping areas clean and change your dog’s drinking water regularly, several times a day. However, the best protection against coli-form bacteria is to develop a healthy intestinal flora. If the intestine becomes imbalanced, perhaps due to an unhealthy or intolerable food, or because of stress, then bacteria can more easily penetrate your dog’s system. A healthy, balanced diet free from harmful substances is of the utmost important to your dog. Alongside antibiotics, it is recommended that you feed your dog a special diet that naturally supports healthy gut flora and contributes to the development of a natural protective barrier.

3. Leptospirosis

Leptospirosis, also known as the “Stuttgart Dog Disease”, is caused by long, spiral bacteria called leptospira, which lurk in contaminated puddles, plants or ponds in wait for their “victims”.  They can be caught directly through the urine of wild animals or rodents carrying these dangerous pathogens. The highly contagious disease, which can cause deadly organ damage particularly in young or immuno-impaired dogs, is a zoonosis, meaning that it can pass between humans and animals. In many European countries, protection against leptospirosis is a mandatory vaccination.


Depending on the bacterial subspecies and the age and constitution of the dog, leptospirosis can present itself in different ways. Some dogs do not show any outward signs of being unwell, with the bacteria being fought off unnoticed inside the body, whilst others are severely impaired. Typical symptoms include fatigue, loss of appetite, vomiting, diarrhoea and fever. Muscle cramps, redness and jaundice can also occur, depending on the bacterial strain. If left untreated, it can cause irreparable liver and kidney damage, which can be fatal, particularly in puppies.


As soon as your vet diagnoses leptospirosis, your dog will be started on a special antibiotic. If kidney or liver damage has already occurred, further treatment steps will be taken to help maintain renal and hepatic function. However, permanent renal insufficiency or liver damage may still be a result of this disease.


The best protection against leptospirosis is vaccination. After all, you will find it hard to prevent your dog from licking or drinking from water sources that may be infected. After being vaccinated as a puppy, a booster should be administered annually to help maintain its effectiveness. It is unlike the vaccinations for distemper, hepatitis and parvovirus, which only need refreshing every three years or so.

4. Salmonellosis

First, the good news: dogs with a healthy immune system are generally quite resistant to the Salmonella pathogens. On the other hand, dogs that are sick, weak or young can become seriously ill, just like humans. Salmonellosis is primarily transmitted through poultry, so the consumption of raw meat or contact with poultry faeces may lead to infection in dogs.


The signs may also differ with this pathogen, depending on the amount of bacteria taken in and the constitution of each individual dog. They range from mild diarrhoea to severe vomiting and diarrhoea that contain blood, as well as fever and the formation of abscesses on internal organs. These in turn can lead to jaundice, lung or joint inflammation and nervous system disorders. Other side effects of salmonellosis are sluggishness and apathy.


Once again, the treatment for this would consist of antibiotics. If internal organs such as liver, kidney or spleen have already been attacked, it may be necessary to combine these with other medicines.


Unlike with leptospirosis, there is no vaccine against salmonellosis. Nevertheless, there are a few measures that can help to reduce the risk of infection. If you feed your dog a raw food diet, you should be sure that you trust the origin of the meat, buying directly from a butcher you know. For high-quality raw meat, you can generally trace it all the way back to the source. Raw poultry from unknown sources should be avoided at all costs. You should also try to make sure that your dog does not come into contact with pigeon or duck faeces.

5. Staphylococci

Staphylococci are found on the skin of both humans and dogs. In the latter, however, subspecies of this pathogen can lead to bacterial dermatitis. The bacteria particularly enjoy the mucous membranes or open wounds, and can be transmitted by other animals or humans.

Symptoms: The skin infection caused by these bacteria usually occurs on the torso, between the toes or on the elbows. In puppies, signs of bacterial infection are usually visible on the stomach. Symptoms include itching, red skin, hair loss, ulcers and boils. Inflammation can spread to the heart, bones and joints.

Treatment: Depending on the pathogen and the severity of the infection, it may be enough to simply wash the infected area with an antibiotic shampoo and treat it with an ointment. If the itching is a problem, it can also be a good idea to put your dog in a cone, so that the affected area cannot be reached with its mouth. In some cases, surgical intervention or detoxification in hospital may be necessary, particularly if the bacteria have caused blood poisoning. If you notice a skin infection on your dog, you should always see your vet as soon as possible, to find out what course of treatment you should take.

Prevention: As with all bacteria, hygiene plays a key role here. Be sure to keep any wounds clean and avoid letting your dog’s tongue come into contact with infected wounds. It is also important to take proper care of your dog, following regular grooming regimes and regularly checking for any changes.

Further bacterial dangers for your dog

Of course, the five infections listed here are not the only dog diseases caused by bacteria. Tuberculosis, listeriosis, yersinia, ehrlichiosis, anaplasmosis, streptococci and tetanus are all bacteria diseases that can offer up a threat to our dogs. Although the individual characteristics differ, the same protection against infection applies to them all – good sanitation and a strong immune system help ensure that few pathogens have a chance to take hold.

Help keep your dog healthy

To strengthen your dog’s immune system and help fight bacteria, you should pay attention to the following points:

  • Feed your dog a healthy, balanced diet. Make sure your food is of the highest quality and ensure that your dog is getting all the vital nutrients it needs through its diet.
  • Throw away leftover food immediately and rinse food bowls thoroughly.
  • Change your dog’s water regularly – at least twice a day!
  • If possible, keep your dog away from puddles or other stagnant water.
  • Avoid contact with animal faeces.
  • Take care of your dog properly. As well as regular grooming, you should cleanse and keep an eye on the skin, ears, paws and mouth. While this will not always prevent infection, it can help ensure that you identify and treat external symptoms more quickly.

We wish you and your dog all the best!

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