Exorchis sp. in the catfish Silurus asotus and Oncomelania hupensis in marshlands of Poyang Lake, China: A potential biological control tool for Schistosoma japonicum.

Oncomelania hupensis is the obligate intermediate host of Schistosoma japonicum, highlighting the medical importance of interrupting this unique and long-standing parasite-host interaction in controlling schistosomiasis transmission. It has been reported that a catfish trematode Exorchis sp. could have the potential to function as an effective anti-schistosomal agent in the snail host. However, the feasibility of this eco-friendly biological control strategy should be comprehensively investigated and evaluated in endemic areas for schistosomiasis. In this study, a field survey was conducted from 2012 to 2016 in the marshlands of Poyang Lake, which is one of the highly endemic regions for schistosomiasis in China. Results showed that more than half of Silurus asotus (65.79%) were infected with Exorchis sp., and the average intensity of infection was 14.21 per fish. And the average infection rate of Exorchis sp. in O. hupensis is 1.11%. These findings indicated that there are abundant biological resources for the implementation of this biology control strategy in the marshlands of Poyang Lake. The data presented here provide solid evidences for the practical application of this biological control strategy, thereby contributing to achieving the goals of the elimination of schistosomiasis.

A brief review on deer keds of the genus Lipoptena (Diptera: Hippoboscidae).

The louse flies of the genus Lipoptena spp. (Diptera: Hippoboscidae) are obligate blood-feeding species and potential vectors of several pathogens. These ectoparasites are known for their potential harm to wild animals. This review summarized the recent research on Lipoptena spp.'s role as potential vectors of pathogens and the impact of climate change on their distribution. The review focused on the biological characteristics, medical and veterinary significance, rapid geographic expansion, and challenges in controlling Lipoptena spp. Finally, we provided some considerations for future research on the Lipoptena spp.

Virulence-related gene wx2 of Toxoplasma gondii regulated host immune response via classic pyroptosis pathway.

BACKGROUND: Toxoplasma gondii is known as the most successful parasite, which can regulate the host immune response through a variety of ways to achieve immune escape. We previously reported that a novel gene wx2 of T. gondii may be a virulence-related molecule. The objective of this study was to explore the mechanism of wx2 regulating host immune response. METHODS: The wx2 knockout strain (RHwx2-/- strain) and complementary strain (RHwx2+/+ strain) were constructed by the CRISPR/Cas9 technique, and the virulence of the wx2 gene was detected and changes in pyroptosis-related molecules were observed. RESULTS: Compared with the wild RH and RHwx2+/+ strain groups, the survival time for mice infected with the RHwx2-/- strain was prolonged to a certain extent. The mRNA levels of pyroptosis-related molecules of caspase-1, NLRP3, and GSDMD and et al. in mouse lymphocytes in vivo and RAW267.4 cells in vitro infected with RHwx2-/- strain increased to different degrees, compared with infected with wild RH strain and RHwx2+/+ strain. As with the mRNA level, the protein level of caspase-1, caspase-1 p20, IL-1ß, NLRP3, GSDMD-FL, GSDMD-N, and phosphorylation level of NF-κB (p65) were also significantly increased. These data suggest that wx2 may regulate the host immune response through the pyroptosis pathway. In infected RAW264.7 cells at 48 h post-infection, the levels of Th1-type cytokines of IFN-γ, Th2-type cytokines such as IL-13, Th17-type cytokine of IL-17 in cells infected with RHwx2-/- were significantly higher than those of RH and RHwx2+/+ strains, suggesting that the wx2 may inhibit the host's immune response. CONCLUSION: wx2 is a virulence related gene of T. gondii, and may be involved in host immune regulation by inhibiting the pyroptosis pathway.

Pattern recognition receptor signaling and innate immune responses to schistosome infection.

Schistosomiasis remains to be a significant public health problem in tropical and subtropical regions. Despite remarkable progress that has been made in the control of the disease over the past decades, its elimination remains a daunting challenge in many countries. This disease is an inflammatory response-driven, and the positive outcome after infection depends on the regulation of immune responses that efficiently clear worms and allow protective immunity to develop. The innate immune responses play a critical role in host defense against schistosome infection and pathogenesis. Initial pro-inflammatory responses are essential for clearing invading parasites by promoting appropriate cell-mediated and humoral immunity. However, elevated and prolonged inflammatory responses against the eggs trapped in the host tissues contribute to disease progression. A better understanding of the molecular mechanisms of innate immune responses is important for developing effective therapies and vaccines. Here, we update the recent advances in the definitive host innate immune response to schistosome infection, especially highlighting the critical roles of pattern recognition receptors and cytokines. The considerations for further research are also provided.

Epitope vaccine design for Toxoplasma gondii based on a genome-wide database of membrane proteins.

BACKGROUND: There is presently no effective and safe vaccine for Toxoplasma gondii for humans. The study described here was designed to search for a novel group of optimal B cell and T cell epitopes from Toxoplasma membrane proteins using genome-wide comprehensive screening. METHODS: The amino acid sequences of membrane proteins of T. gondii were obtained from the UniProt database. The ABCPred and BepiPred servers were employed to predict the linear B cell epitopes. The Immune Epitope Database (IEDB) online service was utilized to forecast T cell epitopes within T. gondii membrane proteins that bind to human leukocyte antigen (HLA) class I (HLA-I) or HLA-II molecules. RESULTS: From the 314 membrane proteins of T. gondii, a total of 14 linear B cell epitopes embedded in 12 membrane proteins were identified. Eight epitopes for major histocompatibility complex (MHC) class I (MHC-I) molecules and 18 epitopes for MHC-II molecules were ultimately selected, for which world population coverage percentiles were 71.94% and 99.76%, respectively. The top rated combinations of linear B cell epitopes and T cell epitopes covering both BALB/c mice and a majority of the human population were identified for the development of a protective vaccine. CONCLUSIONS: The ultimate vaccine construct described here, which comprises B cells, MHC-I and MHC-II epitopes, might protect individuals against T. gondii infection by inducing humoral and cellular immune responses.

A case of severe hookworm infection / 中南大学学报(医学版)

With the improvement of sanitation, the infection rate of hookworm is greatly reduced and the severe infected case is rarely reported. Combined morphological and molecular biological examinations, a severe hookworm infection patient was diagnosed in Department of Laboratorial Examination, Quanzhou First Affiliated Hospital of Fujian Medical University. The morphological methods such as direct fecal smear microscopy, saturated brine flotation and hookworm larvae culture methods were used to identify the eggs and larvae from stool samples of the patient. There were a large number of hookworm eggs in patient's stool samples, and the average count was 60 840 per gram by modified Kato method, which belonged to severe hookworm infection. Meanwhile, to distinguish the hookworm species, the semi-nested RT-PCR assay was employed to detect hookworm internal transcribed spacer series from eggs in patient's stool samples, and the result showed that the hookworm species was confirmed to be Necator americanus.