Parasitology

Bovine hemoplasmas are bacteria found on the erythrocyte surface or free in the plasma of cattle. The aim of the present study was to evaluate the occurrence of 'Candidatus Mycoplasma haemobos' ('C. M. haemobos') in Holstein and Jersey cattle raised in Londrina and surroundings, northern region of the State of Parana, Southern Brazil. PCR testing directed to 16S rRNA gene fragment was performed to investigate the occurrence and characterize the molecular identity of 'C. M. haemobos'. A total of 264/433 (60.97%) blood samples were positive by PCR. Further alignment of 500-bp amplicons to available sequences at the GenBank database showed high identity (100%) to 'C. M. haemobos'. To the author's knowledge, this is the first molecular confirmation of the hemoplasma 'C. M. haemobos' in cattle from Brazil. Moreover, 'C. M. haemobos' was observed in high occurrence in dairy cattle, and may have significant impact in livestock production.

ABSTRACT Both Helicobacter pylori and “ Candidatus Helicobacter heilmannii” infections are associated with peptic ulcers, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue (MALT) lymphomas. However, good animal models of H. pylori clinical diseases are rare. In this study, we aimed to establish an animal model of “ Candidatus Helicobacter heilmannii” gastric MALT lymphoma. We used a urease-positive gastric mucosal and mucus homogenate from a cynomolgus monkey maintained in C57BL/6 mouse stomachs. The bacterium in the homogenate was identified as “ Candidatus Helicobacter heilmannii” based on a DNA sequence analysis of the 16S rRNA and urease genes. Mucosal and mucus homogenates were used to inoculate C57BL/6 mice, which were then examined for 24 months. We observed a gradual increase in the surface area of protrusive lesions in almost all infected C57BL/6 mouse fundic stomachs 6 months after infection. Light microscopic observations revealed an accumulation of B lymphocytes along with destruction of glandular elements and the presence of lymphoepithelial lesions consistent with low-grade MALT lymphomas. Electron microscopic observation revealed numerous “ Candidatus Helicobacter heilmannii” bacilli in the fundic glandular lumen, the intracellular canaliculi, and the cytoplasm of intact cells, as well as damaged parietal cells. In conclusion, “ Candidatus Helicobacter heilmannii” induced gastric MALT lymphomas in almost 100% of infected C57BL/6 mice after a 6-month period associated with the destruction of parietal cells.