Gastritis: helicobacter in Cats (Felis) | Vetlexicon
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Gastritis: helicobacter

ISSN 2398-2950

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Synonym(s): stomach, gastric


  • Still controversy as to whether helicobacter causes disease in domestic carnivores.
  • May be considered to be part of the normal flora of dogs and cats.
  • Cats may be asymptomatic carriers of Helicobacter pylori, H. felis and Hheilmannii.
  • Cause: spiral bacteria - Helicobacter felis  Helicobacter spp, H. heilmannii and H. pylori are zoonotic.
  • Signs: most animals are asymptomatic, however helicobacters have been associated with chronic vomiting.
  • Diagnosis: brush cytology, histological examination, urease test.
  • Treatment: antibiotics, with or without H2 antagonists or proton pump inhibitors.
  • Prognosis: excellent with appropriate therapy.

Presenting signs

  • Vomiting Vomiting (usually chronic).
  • Anorexia.
  • Weight loss.

Age predisposition

  • Gastritis becomes more severe with age.

Public health considerations

  • Helicobacter felis, H. heilmannii and H. pylori have been implicated as zoonoses.
  • Studies suggest many cats harbor spiral organisms without clinical signs of gastritis.



  • Helicobacter may cause gastritis Stomach: chronic gastritis and lymphofollicular hyperplasia in cats.
  • Organisms may be observed in healthy cats.
  • Clinical presentation might therefore be unrelated to the presence of helicobacters, and instead result from other causes of chronic vomiting Vomiting
  • Further studies are required to confirm clinical importance of Helicobacter spp.


  • Helicobacter felis Helicobacter spp, H. heilmannii and H. pylori appear to be pathogenic in people.
  • These species have been identified in healthy and sick cats (H. pylori only in an isolated cat colony).
  • Organism colonizes mucus and occasionally parietal (gastric acid secreting) cells   →   produce urease to convert urea to ammonia and produce alkaline microenvironment.
  • Marked lymphoid follicular hyperplasia associated with infection.
  • Potential breakdown in gastric mucosa barrier.
  • Gastritis potentially becomes more advanced - atrophic gastritis.
    Spiral bacteria found in up to 90% of domestic carnivores, depending on the methodology used for detection.


  • Months to years.


Presenting problems

  • Vomiting.

Client history

  • Abdominal pain.
  • Anorexia.
  • Weight loss.

Clinical signs

  • Often appear normal on clinical examination. Particularly with asymptomatic carriers.
  • Abdominal discomfort.

Diagnostic investigation


  • Culture is extremely difficult and can only be performed accurately by specialized laboratories. 
  • Identification of organism by PCR PCR (Polymerase chain reaction). PCR may also be used to determine the particular species present.


  • Spiral organisms can be identified on hematoxylin and eosin stained gastric mucosal biopsies, or using modified Giemsa or silver stains.


  • Gastric mucosa brush cytology may demonstrate small spiral organisms. However, in many cases these may be harmless commensals colonizing the superficial gastric mucus.


  • Demonstration of presence of urease producing organism:
    • A small fresh gastric biopsy sample is innoculated in urea broth containing phenol red pH indicator   →   bacterial urease production   →   ammonia production and color change to pink within 12 hours.
    • Urea breath testing.

Confirmation of diagnosis

Discriminatory diagnostic features

  • Clinical signs.
  • Positive brush cytology or histopathology.
  • Demonstration of presence of urease producing bacteria.

Definitive diagnostic features

Gross autopsy findings

  • Patchy focal gastritis.

Histopathology findings

  • Lymphofollicular gastritis with inflammation in subglandular region of gastric mucosa.
  • Diffuse lymphocytic infiltrates with plasma cells and eosinophils.
  • Ulceration - relationship of infection to this is unresolved.
  • Neoplasia - relationship of infection to this is unresolved.

Differential diagnosis


Initial symptomatic treatment

Only consider eradicating Helicobacter in patients with a biopsy diagnosis of gastritis or lymphoma.

Standard treatment

Triple therapy usually recommended

  • Various ‘triple’ or even ‘quadruple’ therapy protocols are described. 
  • Current triple therapy usually involves: 
    • Two antibiotics combined – typically amoxicillin  Amoxicillin (20 mg/kg TID) and metronidazole Metronidazole (10-15 mg/kg BID); AND 
    • Bismuth subsalicylate Bismuth salts (tablet or suspension). 
  • Current quadruple therapy involves the above protocol with famotidine Famotidine additionally prescribed. However, the use of famotidine did not provide additional benefit in one study. 
  • Proton pump inhibitors may provide superior acid suppression to H2 antagonists. Omeprazole Omeprazole has been demonstrated to reduce H. pylori colonization density in people, and might increase the stability and concentration of amoxicillin and other antibiotics within the gastric lumen where organisms are found, as well as allow better distribution to the mucosa. 
  • Modified triple therapy includes combined antibiotic therapy with amoxicillin and clarithromycin Clarithromycin (7.5 mg/kg), together with bismuth. Administration of clarithromycin may provide better clearance of intracellular organisms, and thereby lower recurrence rates. 
  • Other treatment protocols have also been described in cats. 




  • Eradication is >80% with appropriate antibiotics.

Expected response to treatment

  • Resolution of vomiting within a few days of starting therapy.
  • It is of course possible that treatment response does not reflect clearance of organisms, but rather that this therapy is treating an alternative condition such as antibiotic responsive inflammatory bowel disease / chronic enteropathy.
  • If no response to therapy determine if Helicobacter were eradicated and reinvestigate other potential causes of vomiting.

Reasons for treatment failure

  • Incorrect diagnosis - spiral bacteria incidental finding on biopsy.
  • Resistance to antibiotics selected.
  • Non-Helicobacter-related gastric disease.

Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Marks S L, Kook P H, Papich M G, Tolbert M K, Willard M D (2018) ACVIM consensus statement: Support for rational administration of gastrointestinal protectants to dogs and cats. JVIM 32(6), 1823-1840 PubMed Full Article.
  • Simpson J (2005) Helicobacter infection in dogs and cats: to treat or not to treat? In Practice 27 (4), 204-207 VetMedResource.
  • Scanziani E, Simpson K W, Monestiroli S et al (2001) Histological and immunohitochemical identification of different Helicobacter species in the gastric mucosa of cats. J Vet Diag Invest 13 (1), 3-12 PubMed.
  • Strauss-Ayali D, Scanziani E, Deng D et al (2001) Helicobacter spp. infection in cats - evaluation of the humoral immune response and prevalence of gastric Helicobacter spp. Vet Microbiol 79 (3), 253-265 PubMed.
  • Neiger R & Simpson K W (2000) Helicobacter infection in dogs and cats: facts and fiction. JVIM 14 (2), 125-133 PubMed.
  • Neiger R, Seiler G, Schmassmann A (1999) Use of a urea breath test to evaluate short-term treatments for cats naturally infected with Helicobacter heilmannii. Am J Vet Res 60, 880-883 PubMed
  • Neiger R, Dieterich C, Burnens A et al (1998) Detection and prevalence of helicobacter infection in pet cats. J Clin Microbiol 36 (3), 634-637 PubMed.
  • Jenkins C & Bassett J R (1997) Helicobacter infection. Comp Cont Ed Prac Vet 19 (3), 267-279 VetMedResource.
  • Lecoindre P, Chevallier M, Peyrol S et al (1997) Pathogenic role of gastric helicobacter spp in domestic carnivores. Vet Res 28 (3), 207-215 PubMed.
  • Happonen I, Saari S, Castren L et al (1996) Comparison of diagnostic methods for detecting gastric helicobacter-like organisms in dogs and cats. J Comp Path 115 (2), 117-127 PubMed.
  • Tennant B (1996) Scientific information document on Helicobacter pylori. JSAP 37 (12), 609-610 PubMed.
  • Geyer C, Colbatzky F, Lechner J et al (1993) Occurance of spiral-shaped bacteria in gastric biopsies in dogs and cats. Vet Rec 133 (1), 18-19 PubMed.

Other sources of information

  • Fox J S (1995) Helicobacter associated gastric disease in ferrets, dogs and cats. In: Current Veterinary Therapy X. W B Saunders, Philadelphia. pp 720-723.