Haemaphysalis longicornis calreticulin is not an effective molecular tool for tick bite diagnosis and disruption of tick infestations.

BACKGROUND: Tick calreticulin (CRT) is a calcium-binding protein secreted into the host during blood feeding. It has been used as a biomarker of tick exposure and has potential as an anti-tick vaccine, but there is no information about these uses for Haemaphysalis longicornis CRT (HlCRT). We synthesized recombinant H. longicornis CRT (rHlCRT) and evaluated its potential for tick bite diagnosis and for disrupting tick infestations. METHODS: The responses of mice and rabbits exposed to H. longicornis ticks were measured with ELISA to determine the antibody level against rHlCRT. To evaluate the effects of rHlCRT-induced anti-tick immunity, engorgement weight, tick engorgement index (TEI), feeding duration, ecdysis rate, and egg weight per engorged tick were compared between ticks fed on immunized and normal mice. RESULTS: Mean anti-tick CRT antibody levels in sera collected from mice at 1 and 15 days after primary tick exposure were not significantly different from the mean antibody levels in negative control mice that were not bitten by ticks (all P values > 0.05). No significant anti-HlCRT IgG responses developed in mice after second exposure to tick bites compared with the level of anti-HlCRT antibody response in negative control mice (all P values > 0.25). For rabbits, no significant differences in the antibody levels were observed in animals before challenge infestation and after tick exposures, and in animals after two tick exposures (all P values > 0.10). There were no significant differences in the body weight of ticks fed on immunized and normal mice (all P values > 0.15). No significant differences in TEI were observed between ticks fed on immunized mice and normal control mice (all P values > 0.50). There were no significant differences in feeding duration for female ticks, and feeding duration and ecdysis rate for nymphs in the experimental and control groups (all P values > 0.10 for feeding duration and P value = 0.19 for ecdysis rate). We did not observe a significant difference in egg weight per tick in the rHlCRT-immunized and the control groups (P = 0.88). CONCLUSIONS: HlCRT in H. longicornis tick saliva proteins appears to be nonimmunogenic to mammalian hosts like mice and rabbits. Vaccination with rHlCRT did not generate effective immunity against parthenogenetic and bisexual H. longicornis nymphs or female ticks. These results indicate that HlCRT is not a suitable molecular candidate for H. longicornis tick bite diagnosis and not effective for the disruption of tick infestations.

Detection and phylogenetic analysis of tick-borne bacterial and protozoan pathogens in a forest province of eastern China.

Ticks, as obligate blood-sucking ectoparasites, feed on a broad range of vertebrates and transmit a great diversity of pathogenic microorganisms. Some tick-borne pathogens (TBPs) are endemic in China, whereas epidemiological studies are limited in Jiangxi, a forest province located in eastern China. Here, we have determined the positivity rates of TBPs in humans, rodents, dogs, goats and ticks, and performed the molecular characterization of TBPs in Jiangxi province. We found a high positivity rate of TBPs in the collected samples, demonstrating 23 (12.92%) samples positive for more than one TBPs. Of those, 11 (6.18%) samples were positive for Rickettsia spp., six (3.37%) Ehrlichia spp./Anaplasma spp., one (0.56%) Bartonella spp., two (1.12%) Borrelia spp., and five (2.81%) Babesia spp. The positivity rates of TBPs varied among ticks, animals, and humans as follow: goats (14/37, 37.84%), ticks (8/35, 22.86%), and dogs (1/11, 9.09%). Humans and rodents were negative for TBP presence. Phylogenetic analyses of these TBP sequences revealed the presence of Rickettsia japonica, Ehrlichia minasensis, and an unclassified Babesia spp. in goats, and Anaplasma phagocytophilum, Borrelia valaisiana, and an unclassified Bartonella spp. in ticks. Furthermore, R. japonica infection was exclusively found in goats with the positivity rate of 29.73%. Our study is the first report of R. japonica in goats around the world. These findings suggest high TBP positivity rates among goats, ticks, and dogs, and diverse TBPs in goats and ticks in the studied sites. Therefore, our results underscore the urgent need to assess TBP-tick-vertebrate-environment interactions and the risk of tick borne disease exposure in humans in the future.

Spatiotemporal Dynamics of Scrub Typhus in Jiangxi Province, China, from 2006 to 2018.

Background: Scrub typhus (ST) has become a significant potential threat to public health in Jiangxi. Further investigation is essential for the control and management of the spatiotemporal patterns of the disease. Methods: Time-series analyses, spatial distribution analyses, spatial autocorrelation analysis, and space-time scan statistics were performed to detect spatiotemporal dynamics distribution of the incidence of ST. Results: From 2006 to 2018, a total of 5508 ST cases occurred in Jiangxi, covering 79 counties. The number of ST cases increased continuously from 2006 to 2018, and there was obvious seasonality during the variation process in each year, with a primary peak in autumn (September to October) and a smaller peak in summer (June to August). From 2007 to 2018, the spatial distribution of the ST epidemic was significant heterogeneity, and Nanfeng, Huichang, Xunwu, Anyuan, Longnan, and Xinfeng were hotspots. Seven spatiotemporal clusters were observed using Kulldorff's space-time scan statistic, and the most likely cluster only included one county, Nanfeng county. The high-risk areas of the disease were in the mountainous, hilly region of Wuyi and the southern mountainous region of Jiangxi. Conclusions: Targeted interventions should be executed in high-risk regions for the precise prevention and control of ST.

Heavy metal contamination in surface sediments: A comprehensive, large-scale evaluation for the Bohai Sea, China.

Heavy metal contamination in the Bohai Sea (China) has been the focus of many studies, but most of them only focused on local pollution levels and thus lacked high spatial resolution for the whole sea. In this study, heavy metals (i.e., As, Cr, Cu, Cd, Pb, Zn, and Fe) in surface sediments were analyzed to assess the spatio-temporal pollution conditions of the Bohai Sea, an important coastal environment consisting of Bohai Bay, Laizhou Bay, and Liaodong Bay. The results indicated that the heavy metal concentration in the sediments was in the range of 6.43-32.18 mg/kg for As, 14.90-58.07 mg/kg for Cr, 3.90-27.19 mg/kg for Cu, 0.04-0.27 mg/kg for Cd, 11.09-30.95 mg/kg for Pb, 18.76-65.58 mg/kg for Zn, and 0.78%-2.55% for Fe. The distribution of heavy metals revealed that the concentrations were relatively low in Laizhou Bay, very high in the northwest coastal region of the Bohai Sea, and decreased from near-shore to off-shore areas. Moreover, both the enrichment factor and geo-accumulation index demonstrated that there was no contamination to be found for Cr, Cu, Zn in the region and a slight to moderate pollution of As, Cd, and Pb. Cd and As presented considerable potential ecological risk as a result of their high toxicity. The potential ecological risk index (RI) suggested that a third of the areas (northwest coastal area of the Bohai Sea) has moderate ecological risk. The risk area was generally decreased as offshore distance increased, which suggested that the contamination and risk of heavy metals are influenced by anthropogenic activities.

Preliminary investigation of ixodid ticks in Jiangxi Province of Eastern China.

In recent years, a large effort has been made for tick surveys for public health importance around China, especially after outbreaks of severe fever with thrombocytopenia syndrome (SFTS) occurred in humans in 2009. In this paper, the preliminary species composition and population distribution of ticks in Jiangxi Province of Eastern China is reported. Ticks were collected in three habitats (grassland, shrubs and woodland) and from nine host groups in 12 sampling sites throughout Jiangxi Province between 2011 and 2018. Six tick species including Haemaphysalis longicornis, Rhipicephalus sanguineus sensu lato, Haemaphysalis yeni, Haemaphysalis kitaoka, Ixodes sinensis and Dermacentor auratus were collected from the vegetation. Haemaphysalis longicornis was most abundant tick species, accounting for 90.6% of the total ticks. Haemaphysalis yeni and H. kitaoka were newly recorded tick species in Jiangxi Province. Tick presence was remarkably greater in grassland (89.4%) than in woodland (9.4%) and shrubs (1.2%), and nymphs (68.2%) and larvae (19.1%) were more frequently found than adult females (6.6%) and males (6.0%). On hosts, a total of 1513 ticks, from 13 species and four genera, were collected. These were H. longicornis, Haemaphysalis campanulata, Haemaphysalis flava, Haemaphysalis phasiana, H. yeni, H. kitaoka, Haemaphysalis hystricis, R. sanguineus (s.l.), Rhipicephalus haemaphysaloides, Rhipicephalus microplus, Ixodes granulatus, I. sinensis and Amblyomma testudinarium. Amblyomma testudinarium was a newly recorded tick species in Jiangxi Province. Based on this investigation, H. longicornis was the most frequently collected species (30.5%) and widely distributed tick species of the total collection ticks (in 11 sampling sites). Haemaphysalislongicornis had a broad host range and its presence (hosts with at least one tick) was significantly greater on Lepus sinensis (33.3%) than on Canis familiaris (2.3%) (χ2 = 23.68, p = 0.0013). In addition, the number of H. longicornis collected on L. sinensis (64.0%) was higher than on other host groups. Of all ticks collected on hosts, different developmental stages were obtained, which included 347 larvae (22.9%), 249 nymphs (16.5%), 404 adult males (26.7%) and 513 females (33.9%) and sex distribution was relatively uniform. These data indicate that a broad range of tick species is widely distributed throughout Jiangxi Province in Eastern China.

[Effect of schistosomiasis control in towns reached criteria of infection controlled in Nanchang City].

OBJECTIVE: To evaluate the effect of schistosomiasis control in towns that had reached the criteria of infection controlled in Nanchang City. METHODS: The residents and livestock of 14 towns that had reached the criteria of infection controlled in Nanchang, Xinjian and Jinxian counties of Nanchang City were sampled to investigate the schistosomiasis endemic situation, Oncomelania hupensis snail status, and data of schistosomiasis control work. RESULTS: The positive rate of serum tests of the residents was 2.58%, and no positive stool samples were found. No cattle or sheep were positive in stool tests. Totally 1 635 snails were caught, and 1278 were alive with an average density of living snails of 0.051/0.1 M2, while no schistosome infected snails were found. All the surveyed administrative villages had the completed files of schistosomiasis control. Conclusion All the 14 towns that had reached the criteria of infection controlled of schistosomiasis have already reached the criteria of transmission controlled in Nanchang City.

[Current status of human Schistosoma japonicum infection and reinfection in marshland and lake regions of Xinjian County, Jiangxi Province, China].

OBJECTIVE: To understand the dynamics of human infection and reinfection of Schistosoma japonicum after chemotherapy in marshland and lake endemic regions so as to provide the evidence for developing a cost-effective control strategy. METHODS: From 2007 to 2011, the schistosome infection, intensities and reinfection of population were investigated and the results were analyzed dynamically in Caohui Village, a national schistosomiasis surveillance site in Changyi Township, Xinjian County, Jiangxi Province, China. RESULTS: The schistosome infection rate was 3.55% and the mean intensity was 1.56 in 2007, and the schistosome infection rate was 1.52% and the mean intensity was 1.60 in 2011. The reinfection rates were 2.70%, 9.09% and 2.47% in 2009, 2010, and 2011, respectively. CONCLUSION: The schistosomiasis endemic situation shows a downtrend in the village. However, the reinfection is still serious; therefore, we should strengthen the research of risk factors of reinfection and control them.

[Epidemic situation of acute schistosomiasis in Nanchang City of Jiangxi Province from 2005 to 2012].

OBJECTIVE: To understand the endemic regulation of acute schistosomiasis in Nanchang City of Jiangxi Province from 2005 to 2012 so as to provide the reference for policy-making of schistosomiasis control. METHODS: The data of acute schistosomiasis were collected and analyzed with the descriptive epidemiology method in Nanchang City from 2005 to 2012. RESULTS: A total of 52 acute schistosomiasis cases were reported in Nanchang City from 2005 to 2012. The morbidity of acute schistosomiasis was 0.003 46% in 2005, and it was 0 in 2012. The morbidity of acute schistosomiasis in different years was significant different (chi2 = 61.077, P < 0.01). The duration of incidence was from May to November, but the peak of the incidence was July. The sex ratio between males and females was 4.78:1 (43:9, chi2 = 22.231, P < 0.01). The ages of cases showed double humps, namely the 6-15 years' group and 30-40 years' group. Most of the acute cases were farmers (65.38%), students (25.00%), and fishermen (3.85%). Fishing and swimming were the main infection ways, with the infection rates of 63.46% and 26.92%, respectively. CONCLUSION: The susceptible populations are peasants and young students; therefore, we should strengthen health education for these high-risk groups.

Severe tick infestation in a hare and potential risk for transmitting pathogens to humans.

Severe tick infestation was found in a hare in a suburban area of Nanchang, Jiangxi Province, China. We sampled ticks and identified them based on their morphologic characteristics. Three species, Ixodes sinensis, which is commonly found in China and can experimentally transmit Borrelia burgdorferi, Rhipicephalus haemaphysaloides, and Haemaphysalis longicornis which can transmit Lyme disease were detected with an optical microscope and a stereomicroscope. Risk of spreading ticks from suburban to urban areas exists due to human transportation and travel between the infested and non-infested areas around Nanchang.

[Antigenic localization of specific allergen in the body of Dermatophagoides pteronyssinus by immunohistochemistry].

OBJECTIVE: To study the localization of specific allergen of Dermatophagoides pteronyssinus. METHODS: Through optical microscope, the specific allergens of D. pteronyssinus were observed in paraffin sections using D. pteronyssinus-specific IgE antibodies from the patient sera. RESULTS AND CONCLUSION: The digestive system was found occupying large parts of body cavity of D. pteronyssinus by HE staining, while the specific allergens of D. pteronyssinus were mostly occurred in the midgut tissue, gut contents, cuticle and reproductive system in the immunostained sections. The results also showed that many parts of D. pteronyssinus were recognized by the specific IgE antibodies obtained from allergic individuals to D. pteronyssinus, which provided a theoretic base for further study of isolation and purification of the specific allergen.