Ehrlichia species in pond-farmed leeches (Hirudinaria sp.) in Hubei Province, China.

Leeches are frequently used in traditional Chinese medicine. However, they are potentially hazardous to human and animal health by transmitting several pathogens. Studies of diseases transmitted by leeches are scarce. The purpose of this study was to analyze the pathogens carried in pond-farmed medicinal leech in China. Leeches were collected from 6 farms in Hubei Province in central China. DNA was extracted from the internal organ of leeches to analyze the origin of blood meal. Leech genera were confirmed through amplification of 18S rRNA and mitochondrial gene cytochrome oxidase I (COI) gene by PCR and host animal species were identified through amplification of mitochondrial cytochrome b gene. Species of Ehrlichia in the leech specimens were screened with PCR using specific primers. PCR amplification and DNA sequencing showed that 620 leeches were Hirudinaria sp. Ehrlichia DNA was detected in 39 specimens from 2 farms. We obtained a total of 65 sequences of the cytB gene from 620 leech internal organ samples including sequences of human (n = 5), rat (n = 1), domestic pig (n = 10), duck (n = 23), goose (n = 12) and buffalo (n = 14). Phylogenetic analysis of the rrs and groEL gene sequences showed that Ehrlichia detected in the study were closely related to Ehrlichia sp. in ticks from Korea and Japan. To the best of our knowledge, this is the first report on Ehrlichia DNA being detected from leeches. Our findings provided new data on Ehrlichia spp. and farmed leech species in China.

Mimicry epitope from Ehrlichia canis for interphotoreceptor retinoid-binding protein 201-216 prevents autoimmune uveoretinitis by acting as altered peptide ligand.

We report here identification of novel mimicry epitopes for interphotoreceptor retinoid-binding protein (IRBP) 201-216, a candidate ocular antigen that causes experimental autoimmune uveoretinitis (EAU) in A/J mice. One mimicry epitope from Ehrlichia canis (EHC), designated EHC 44-59, induced cross-reactive T cells for IRBP 201-216 capable of producing T helper (Th)1 and Th17 cytokines, but failed to induce EAU in A/J mice. In addition, animals first primed with suboptimal doses of IRBP 201-216 and subsequently immunized with EHC 44-59 did not develop EAU; rather, the mimicry epitope prevented the disease induced by IRBP 201-216. However, alteration in the composition of EHC 44-59 by substituting alanine with valine at position 49, similar to the composition of IRBP 201-216, enabled the mimicry epitope to acquire uveitogenicity. The data provide new insights as to how microbes containing mimicry sequences for retinal antigens can prevent ocular inflammation by acting as naturally occurring altered peptide ligands.