Evidence of Helicobacter spp. in Saliva and Gastric Mucosa of Domestic Dogs in the Central Region of Rio Grande do Sul, Brazil

Abstract

Helicobacter pylori is a spiral-shaped bacterium, which plays a role in the aetiology of gastric diseases in humans. Non-H. pylori Helicobacter (NHPH) species naturally colonise the stomach of animals and also induce gastric lesions in humans, highlighting their zoonotic importance. We evaluated the gastric bacterial colonisation density and gastric lesions and sought to identify the main phylogenetic groups of the Helicobacter spp. obtained from dogs in the central region of Rio Grande do Sul, Brazil, with this study aiming to investigate the occurrence of Helicobacter spp. in saliva and gastric samples from these dogs. This study included 35 dogs and used analysis such as cytology, histopathology, PCR, rapid urease testing, and phylogenetic analysis. Of the dogs, 94.3% were positive for Helicobacter spp., and these bacteria were present in the stomach of 32 dogs and saliva of eight. Respectively, eight, 15, and nine dogs had mild, moderate, and severe colonisation. Lymphocytic-plasmacytic infiltrate was the main gastric lesion. However, the presence of Helicobacter and the density appeared to be unrelated to the gastric lesions. The samples possessed a high nucleotide identity with remarkably similar sequences among some of the species of NHPH such as H. heilmannii s.s., H. salomonis, H. felis, and H. bizzozeronii. The saliva of domestic dogs, even of those who appear clinically healthy, can cause Helicobacter infection in humans and other animals, with, in these dogs, increased density, occurrence rate, and predominance of NHPH of zoonotic importance being found in the stomach with a lower occurrence of Helicobacter spp. in the saliva.

Helicobacter spp. in the Stomach of Cats: Successful Colonization and Absence of Relevant Histopathological Alterations Reveals High Adaptation to the Host Gastric Niche

“…Additionally, the presence of H. pylori in feline stomachs has been seldom reported [ 16 , 17 , 18 , 19 ], and this finding brought attention to the putative role of cats as reservoirs [ 18 , 19 ]. However, the distribution and incidence of the various Helicobacter species in cats appears to be influenced by local geography and climate [ 20 ].…”

Gastric Helicobacter species associated with dogs, cats and pigs: significance for public and animal health

“…Several research groups did not find any correlation between NHPH infection and (the severity of) gastric lesions in dogs [ 60 , 64 – 68 ]. However, Kubota-Aizawa et al reported that infection of dogs with gastric NHPH, particularly H. heilmannii s.s., may be associated with more severe gastritis compared to dogs negative for NHPH.…”

“…The prevalence of gastric NHPH in dogs and cats is found to be high, irrespective of clinical signs. The prevalence of gastric NHPH in clinically healthy dogs ranges between 67 and 86% and between 61 to 100% in dogs presented for investigation of chronic vomiting [ 9 , 60 , 64 , 67 , 68 , 71 , 73 – 76 ]. In naturally infected dogs, H. bizzozeronii was reported to be the most prevalent gastric NHPH [ 67 , 77 , 78 ].…”

“…Gastric NHPH have already been detected in the saliva and feces of dogs and cats, suggesting that transmission could happen via saliva and feces [ 64 , 65 , 80 ]. On the other hand, Craven et al .…”

“…Prevalence rates of gastric NHPH infections in human patients undergoing a gastroscopy have been reported to vary between 0.2% and 6%, depending on the geographical area and the detection methods used [ 9 , 82 ]. Populations where animals and humans live closely together and sanitary conditions are poor could be prone to an increased NHPH prevalence rate [ 64 ]. PCR-based studies investigating human gastric biopsy samples with histological evidence of presence of NHPH showed that H. suis had the highest prevalence (14 to 37%), followed by H. salomonis (21%), H. felis (15%), H. heilmannii s.s. (8%) and H. bizzozeronii (4%) [ 3 , 75 , 83 ].…”