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Helicobacter Infection in Dogs

Under normal conditions, the Helicobacter bacteria are benign inhabitants of the intestinal tract, being found in several species, including domestic animals such as dogs, cats, ferrets and pigs, in wild animals such as cheetah's and monkeys, and in humans. While gastric infection due to Helicobacter pylori is a major health problem in humans – it has been associated with gastritis, gastric tumor, and peptic ulcer in affected people – the significance of the Helicobacter bacterium in dogs and any correlation to gastric dysfunctions is still largely unclear (H. pylori specifically is not found in dogs).

Various species of Helicobacter organism have been isolated from the stomachs of cats and mixed infections can present, which sometimes complicates the diagnosis. The most common forms of Helicobacter found in dogs are Helicobacter felis and Helicobacter heilmannii. Other species of Helicobacter found in dogs are Helicobacter rappini, and Helicobater salomonis. The bacteria inhabit the mucosal lining of the stomach, and the glandular cavities.

There are some reports of isolation of Helicobacter from the livers of dogs with hepatitis but this remains anecdotal. Infection from this bacteria is difficult to eradicate entirely and may last from months to years – even for a lifetime, in some dogs.

Symptoms and Types

Most cases remain without any symptoms at all. In others the following symptoms may be seen:

• Vomiting
• Dehydration
• Poor appetite
• Bowel sounds
• Abdominal pain
• Weight loss
• Diarrhea
• Weakness
• Sudden death

Causes

Gastric Helicobacter felis, Helicobacter heilmannii, Helicobacter rappini, and Helicobater salomonis infection. The method by which this infection is transmitted remains unknown, but because of its higher prevalence in shelter dogs, oral and/or fecal transmission is considered a possibility. This assumption is supported by the presence of Helicobacter-like organisms, called GHLOs, in the vomit, feces and saliva of animals that have been infected. There is also some suspicion that the bacteria may be transmitted by water, as GHLOs have been found in some surface waters.

Poor sanitary conditions and overcrowding appear to facilitate the spread of infection.

Diagnosis

Establishing a definitive diagnosis of Helicobacter infection is difficult in most instances. Your veterinarian will perform a complete physical examination with routine laboratory tests including a complete blood count, biochemistry profile, and urinalysis. Your veterinarian may also take a sample from stomach wall and stain it with May-Grünwald-Giemsa, Gram, or Diff-Quik stains, which can easily demonstrate the presence of this organism by making it visible under microscope.

An endoscopic examination is of great help for direct observation of the stomach walls as well as for taking tissue samples for further processing. This procedure uses a device called an endoscope, a camera situated at the end of a flexible tube, which is threaded into the stomach through the esophagus. A polymerase chain reaction (PCR) test is often used both to confirm the presence of Helicobacter in a given sample and to differentiate between the species of Helicobacters. However, confirmation can also be made by taking a tissue sample using the endoscope and observing the sample through microscope.

Note that the presence of gastric Helicobacters in the body do not necessarily indicate an infection that needs to be treated.