E. Coli infection in Dogs

4 min read

Colibacillosis in Dogs

Colibacillosis is a disease caused by the bacterium Escherichia coli, commonly known as E. coli, which normally resides in the lower intestines of most warm blooded mammals, including dogs. Normally, the presence of E. coli is benign, and even beneficial, but in some cases it can cause a diseased condition, especially in newborn puppies.

E. coli infection is most commonly seen in puppies in the first weeks of life. In the first day after giving birth, bitches produce a watery milk that is rich in antibodies. This milk, called colostrum, plays a pivotal role in protecting a newborn puppy's undeveloped immune system against various infections, as it coats the intestinal tract, protecting the puppy from most infections. In the absence of these antibodies, puppies are more vulnerable to a number of infections, including E. coli infection.

If the pregnant bitch is infected with E. coli, the bacteria can also invade a puppy’s blood supply while it is still in uterus, during birth, or the puppy can acquire the infection from feeding from its mother's inflamed mammary glands.

Colibacillosis often leads to a condition called septicemia, or blood poisoning, meaning there is an dangerously high presence of bacteria in the blood. Though primarily a disease of young dogs, it can also affect older dogs. E. coli infection, when combined with other infectious agents, also increases the severity of parvovirus infection in dogs. 

Symptoms and Types

Colibacillosis is sudden (acute) in nature and may cause the following symptoms in an affected puppy:

  • Depression
  • Dehydration
  • Lack of appetite
  • Vomiting
  • Rapid heart rate
  • Weakness
  • Lethargy
  • Watery diarrhea
  • Cold skin (due to low body temperature)
  • Bluish colored mucous membranes (i.e., gums, nostrils, lips, ears, anus) due to inadequate oxygen in red blood cells


Colibacillosis is ultimately due to an E. coli infection. However, risk factors for this type of infection include poor health and nutritional status of the pregnant bitch, lack of colostrum (first milk) to the puppy, unclean birthing environment, difficult or prolonged birth, crowded facilities, concurrent infection/disease, inflammation of the mammary glands in the nursing bitch, and placement of intravenous catheter.


Due to the acute onset of this disease, few abnormalities may be noted in blood testing. In order to see if E. coli, or any other infectious agents are present in the dog's blood, your veterinarian will take blood, urine, and if possible, fecal samples for culture.

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