Prevalence and Sequence Analyses of Neorickettsia risticii

Abstract

The presence of Neorickettsia (Ehrlichia) risticii DNA was confirmed by PCR amplification and sequence analysis from cercaria in snails collected from stream water in Chungcheong and Jeonra provinces. A total of 3,219 snails were tested for trematode cercariae and N. risticii infection. N. risticii 16S rRNA gene fragment was amplified in cercariae from Semisulcospira libertina and Radix auricularia coreana snails by nested PCR. More than four genus cercariae (Schistosomatidae, Microphallidae, Furcocercus, and Xiphidiocercaria) as well as unidentified cercariae were found from Semisulcospira libertina snails. Three species of cercariae (E. cinetorichis, E. hortense, and Fasciola sp.) were found from Radix auricularia coreana snails. The cercariae were present in 429 (13.3%) snails of 3,216 collected at the Chungcheong and Jeonra provinces. The prevalence of N. risticii in these 429 cercariae was 17.9% (77 of 429 cercariae-infected snails). The amplicons of N. risticii 16S rRNA gene fragment (527 bp) from cercariae DNA had two genotypes (NR-JA1 and NR-JA2) with an identity of 96.4% between their nucleotide sequences. However, when compared to the sequence of N. risticii Shasta strain these sequences showed a 94.3% and 96.4% homology, respectively. The comparison of N. risticii 51 kDa major antigen gene sequences (572 bp) from NR-JA1 and NR-JA2 were 100% identical to the sequence of the isolates from Juga sp., Caddisfly larvae, Shasta, Juga yrekaensis, and trematode of California. This study reports for the first time the detection of N. risticii from cercariae found in Radix auricularia coreana snail. These data also indicate that N. risticii could be widespread in Korea.

Further insights in the Tardigrada microbiome: phylogenetic position and prevalence of infection of four new Alphaproteobacteria putative endosymbionts

“…Finally, the bacteria with the sequences ETS1 and ETS2 are likely facultative symbionts as their closest relatives (Neorickettsia and Ca. Xenolissoclinum) also infect at low prevalence and can be pathogens (Chae et al, 2003;Kwan & Schmidt, 2013).…”

Serological Reactivity toEhrlichia canis, Anaplasma phagocytophilum, Neorickettsia risticii, Borrelia burgdorferiandRickettsia conoriiin Dogs from Northwestern Spain

“…Nr, the etiological agent of Potomac horse fever, has been established to be endemic in North America (Neer and Harrus 2006), so any evidence of this infection in other regions must be taken very cautiously. However, in the last few years, several publications have cited serological and/or molecular evidence of Nr in other countries such as Korea, Uruguay, and Thailand (Suksawat et al 2001;Dutra et al 2001;Chae et al 2003). Consistent with these findings, among the five seropositive dogs from Pontevedra, three showed antibody titers above the cutoff and were seronegative to the rest of the tested antigens, which suggests the possible existence of Nr (or other serologically related agent) in this province, although scarcely present and limited to a small area.…”

Molecular Survey of Anaplasmataceae Agents and Coxiellaceae in Non-Hematophagous Bats and Associated Ectoparasites from Brazil

“…For molecular detection of N. risticii, DNA samples were submitted to a nested PCR based on the 16S rRNA gene, as previously described [86]. Additionally, the positive samples for the 16S rRNA were submitted to PCR assays targeting the nearly full-length 16S rRNA [87], p51kDa, and groEL [43,63,88] genes.…”