Abstract
In 1982 a new bacterial pathogen called Campylobacter pylori was discovered in human stomach. In 1990 it was re-named (Helicobacter pylori). Carried by half the global population it was first believed to be exclusive to Human. Its association with peptic ulcer disease revolutionised treatment with antibiotics instead of surgery. Other clinical problems include chronic gastritis, duodenal ulcer and hepatitis. The relationship to gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue lymphoma (MALT) made H. pylori the only bacterial agent to be classified as Class 1 carcinogen.
Detailed investigations were delayed until the genetic technical advances early 21st Century when Helicobacter was genotyped. Poly Chain Reaction amplification and DNA/RNA sequencing allowed diagnosis and research particularly the genomic pathogenesis. Genetics revealed that H.pylori was transmitted to ancient stone-age man from animals. Several genes were identified as virulence factors responsible for chronic inflammation and carcinogenesis. Helicobacter genome is heterogenous and amazingly polymorphic in different species and strains as a result of adaptation to various environmental factors, geographic locations, and hosts. Pathogenecity is therefore variable between ethnic and geographic groups. Several bacterial strains with different pathogenecity may exist in one host.
H. pylori may infect animals. Sheep may act as a reservoir. Other Helicobacter species were identified in farm, small, wild animals, and non-human primates causing chronic vomiting, gastritis, and occasionally lymphocytic gastric tissue proliferation and cancer. Some animal and avian species are contagious to human. Helicobacter infections were subsequently grouped into H.pylori and non-H. pylori. Mixtures of both types is found in both human and animals either as commensals or as pathogens. There are currently about 35 Helicobacter species.
This study highlights the importance of Helicobacter species as a potential zoonotic pathogen and carcinogen with particular attention to Iraq. Recommendations regarding food and social habits are made. Further possible research options are explored.
Key words: Zoonosis, Infection, Carcinogenesis, Helicobacter, Veterinary,
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