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Ticks, as a group, are second only to mosquitoes as vectors of pathogens to humans and are the primary vector for pathogens of livestock, companion animals, and wildlife. The role of ticks in the transmission of viruses has been known for over 100 years and yet new pathogenic viruses are still being detected and known viruses are continually spreading to new geographic locations. Partly as a result of their novelty, tick-virus interactions are at an early stage in understanding. For some viruses, even the principal tick-vector is not known. It is likely that tick-borne viruses will continue to emerge and challenge public and veterinary health long into the twenty-first century. However, studies focusing on tick saliva, a critical component of tick feeding, virus transmission, and a target for control of ticks and tick-borne diseases, point toward solutions to emerging viruses. The aim of this review is to describe some currently emerging tick-borne diseases, their causative viruses, and to discuss research on virus-tick interactions. Through focus on this area, future protein targets for intervention and vaccine development may be identified.

To control the spread of tick-borne diseases, there is an urgent need to develop a reliable technique that can distinguish different species of ticks. DNA barcoding has been proved to be a powerful tool to identify species of arthropods, but this technique has not yet been developed for identifying ticks. Here, we screened and analyzed 1082 sequences of ticks from BOLD system and GenBank, consisting of 647 16S, 325 COI, and 110 18S. These sequences are reported in previous studies and considered to be correctly identified at the species level. Through the analyses of genetic divergences and neighbor-joining (NJ) phylogenetic relationships between the species of ticks, our results show that COI and 16S are reliable in discriminating species of ticks and the 18S could discriminate ticks at the genera level. New universal primers for 16S, 18S, and COI of ticks were designed and a DNA barcoding system for the Ixodida was developed. To assess the performance of this system, 57 specimens of ticks were collected within China. Our results show that DNA barcoding system could correctly identify the species of specimens in adult and subadult stages. This system would assist non-taxonomists to conveniently identify the species of Ixodida based on DNA sequences rather than morphological traits. However, there are still serious deficiencies in the information of 16S and COI of some species of ticks, and additional research is needed to resolve this problem. [ABSTRACT FROM AUTHOR]

Objective: The present study was conducted to prepare and characterize a monoclonal antibody (mAb) against the nucleocapsid (N) protein of Schmallenberg virus (SBV)., Methods: The SBV N gene was cloned into pET-28a-c(+ and pMAL-c5X vectors and then transformed into E.coli BL21. Histidine (His)-tagged (His-SBV-N) and maltose-binding protein (MBP)-tagged (MBP-SBV-N) fusion proteins were respectively induced to express by IPTG and purified by nickel-nitrilotriacetic acid (Ni-NTA) agarose and amylose resin. His-SBV-N was used to immunize BALB/c mice to prepare mAb, and MBP-SBV-N was used as the coating antigen in ELISA to screen mAb-secreting hybridomas and to determine mAb titers. The mAb against SBV N protein was purified from the ascitic fluids using protein G sepharose. Western blotting and indirect immunofluorescence assay were utilized to analyze the reactivity and specificity of the mAb., Results: One mAb specific for SBV N protein (named 1F2) was successfully screened and purified. The titer of 1F2 was 1:32 000. Besides, the isotype of 1F2 was determined to be IgG2α/κ. 1F2 reacted with both recombinant SBV N proteins and SBV isolates. It was also cross-reactive with the N proteins of genetically related Shamonda, Douglas and Akabane viruses, but not with the Rift Valley fever virus N protein., Conclusion: One mAb specific for the SBV N protein was successfully prepared, it provides a useful tool for the serological detection of SBV.

The protozoan parasite Bonamia ostreae is a destructive pathogen of flat oysters and has been reported to be widespread in Europe and North America. The biological characteristics of this unicellular parasite are still not fully understood. In this study, 104 Ostrea edulis imported from the USA to the Guangdong province of China for consumption were examined for Bonamia infection. PCR assay, combined with restriction fragment length polymorphism, sequencing and BLAST analysis, showed that B. ostreae DNA could be detected in 1 of the 104 oyster samples. Light microscopy revealed Bonamia-like organisms in the oyster. PCR assay and fluorescent in situ hybridization showed that B. ostreae organisms were present and retained their integrity after 4 wk in culture. Acridine orange-ethidium bromide staining indicated that the B. ostreae were still alive. In conclusion, B. ostreae was present in oysters imported to China. More importantly, the parasite was able to survive for at least 4 wk of in vitro culture at 4°C, which further implied a long-term transmission risk of B. ostreae. Considering the wide culture beds of Crassostrea ariakensis and C. gigas in China, and that C. ariakensis and C. gigas are susceptible hosts or reservoirs of B. ostreae, our study highlights the potential risk of introducing B. ostreae by importing O. edulis from a Bonamia endemic area.

Perkinsus is a genus of unicellular protozoan parasite responsible for mass mortality of several commercially valuable mollusks. Surveillance and inspection of its epidemiology in the field calls for convenient and rapid detection methods. Here, a loop-mediated isothermal amplification (LAMP) assay was developed to detect the presence of Perkinsus spp. in mollusks. Specific LAMP primers were designed targeting the conserved internal transcribed spacer 2 (ITS-2) region of the rRNA gene of Perkinsus spp. Using ITS-2 recombinant plasmid as a template, we optimized the LAMP reaction system and conditions and then evaluated the analytical sensitivity and specificity of the assay. The LAMP assay was validated using clam samples collected from coastal areas in eastern China and oysters imported to China and compared with the traditional Ray's fluid thioglycollate culture method (RFTM). Our results showed that the LAMP detection method for Perkinsus was successful. The detection limit was 10 copies of plasmid DNA. Compared to the RFTM assay, the LAMP detection method was more sensitive (56 versus 52 positive out of 60 samples). P. olseni and P. marinus from infected hosts were successfully detected by this method. The LAMP method is rapid, sensitive, and specific for Perkinsus spp. detection, and could be used to screen for perkinsosis both on farms and at ports.