BackgroundBabesiosis is an emerging health risk in several parts of the world. However, little is known about the prevalence of Babesia in malaria-endemic countries. The area along the China-Myanmar border in Yunnan is a main endemic area of malaria in P.R. China, however, human infection with Babesia microti (B. microti) is not recognized in this region, and its profile of co-infection is not yet clear.MethodsTo understand its profile of co-infections with B. microti, our investigation was undertaken in the malaria-endemic area along the China-Myanmar border in Yunnan between April 2012 and June 2013. Four parasite species, including B. microti, Plasmodium falciparum (P. falciparum), P. vivax, and P. malariae, were identified among 449 suspected febrile persons detected by nested polymerase chain reaction (PCR) assay based on small subunit ribosomal ribonucleic acid (RNA) genes of B. microti and Plasmodium spp.ResultsOf all the collected samples from febrile patients, mono-infection with B. microti, P. vivax, P. falciparum, and P. malariae accounted for 1.8% (8/449), 9.8% (44/449), 2.9% (13/449), and 0.2% (1/449), respectively. The rate of mixed infections of B. microti with P. falciparum or P. vivax are both 0.2% (1/449), and mixed infections of P. falciparum and P. vivax accounted for 1.1% (5/449).ConclusionsThis report supports the hypothesis that babesiosis caused by B. microti is emerging along the China-Myanmar border in the Yunnan province, P.R. China, but it was ignored because of low parasitemia or mixed infection with Plasmodium spp. More sensitive and specific diagnosis methods are needed to find the rapid response mechanism of emergency for babesiosis and malaria co-prevalence areas.

BackgroundCystic echinococcosis is a global parasitic disease caused by infection with Echinococcus granulosus larvae with potentially life-threatening complications in humans. To date, the status of the immune cells believed to be associated with the pathogenicity of E. granulosus infection has not been demonstrated clearly.Methodology/Principal FindingsIn this study, we developed a multiplex flow cytometry assay to investigate the systemic immune status of innate and adaptive immunity at 30, 180, 360 days post-infection (dpi) in mice infected with E. granulousus. At 30 dpi, an increase in the number of CD11b+ and CD11c+ antigen-presenting cells (APCs) was observed. This was accompanied by the slight down-regulated expression of the co-stimulatory molecule MHC-II, indicating the impairment of APCs in early infection through the release of secretory-excretory products. In all infected groups, we observed a significant increase in innate immune cells, including APCs and GR-1+ cells, and a dramatic increase in the myeloid-derived suppressor cells (MDSC) expressing CD11b+/GR-1+. Moreover, the upregulation of the activated markers CD69, CD44, CD40L, and the downregulation of CD62L were observed in the CD4+ and CD8+ T cells following infection. Regulatory T cells expressing CD4+/CD25+/FoxP3 + increased significantly over the course of infection.ConclusionsOur findings demonstrate that the microenvironment in the peripheral immune system after E. granulosus infection changes in subtle but detectably ways, especially during the persistent period of infection. We found that T cells were activated following infection, but observed that the significant increase of immunosuppressive cells such as MDSC and Treg cells could inhibit T cell response to E. granulosus antigens. We suggest these cells may play a neglected but key role in the downregulation of the immune response in long-term parasitic infection. Understanding the basic functions and temporal interactions of these immunosuppressive cells will pave the way for new strategies of parasite vaccine design.

BackgroundCystic echinococcosis, caused by infection with Echinococcus granulosus, is one of the most widespread zoonotic helminth diseases. Modulation of host responses is an important strategy used by helminth parasites to promote infection. To better understand the mechanisms adopted by E. granulosus to escape host immune responses, we investigated the effects of excretory–secretory products (ES) and adult worm antigen (AWA) derived from adult E. granulosus on murine bone marrow-derived dendritic cells (BMDC).ResultsCompared with lipopolysaccharide (LPS), AWA, but not ES, induced BMDC maturation or stimulated BMDC cytokine production and co-stimulatory molecule expression (CD40, CD80 and MHC class II). Furthermore, ES-treated BMDCs pulsed with ovalbumin exhibited reduced co-stimulatory molecule expression in comparison with untreated BMDC, even in the presence of the strong Th1 inducer, CpG. Moreover, we detected the effects of ES-treated DC on T cell activation by an in vitro T cell priming assay. We observed that ES-treated BMDC co-cultured with DO11.10 transgenic CD4+ T cells induced the generation of CD4+CD25+Foxp3+ T cells. In addition, in contrast to AWA-treated BMDCs, which had markedly induced IFN-γ secretion and reduced of IL-4 levels in co-cultured T cells, ES-treated BMDCs did not modify their capacity to stimulate IFN-γ or IL-4 production by T cells.ConclusionsWe conclude that ES of adult E. granulosus inhibited DC function, impaired the development of Th1 cells induced by CpG, and induced CD4+CD25+Foxp3+ regulatory T cells in an IL-10-independent manner.

Babesiosis is a tick-borne, zoonotic disease caused by Babesia spp. Two cases of babesiosis were detected by nested polymerase chain reaction (PCR) in Yunnan province, China, and further confirmed by molecular assay. The blood smears showed intraerythrocytic ring form and tetrads typical of small B. microti. In both cases, the rapid diagnostic test (RDT) ruled out the possibility of co-infections with malaria. Neither case was initially diagnosed because of the low Babesia parasitemia. These two cases of babesiosis in areas along the Myanmar–China border pose the question of the emergence of this under recognized infection in countries or areas where malaria is endemic.

China has set a goal to eliminate all malaria in the country by 2020, but it is unclear if current understanding of malaria vectors and transmission is sufficient to achieve this objective. Anopheles sinensis is the most widespread malaria vector specie in China, which is also responsible for vivax malaria outbreak in central China. We reviewed literature from 1954 to 2016 on An. sinensis with emphasis on biology, bionomics, and molecular biology. A total of 538 references were relevant and included. An. sienesis occurs in 29 Chinese provinces. Temperature can affect most life-history parameters. Most An. sinensis are zoophilic, but sometimes they are facultatively anthropophilic. Sporozoite analysis demonstrated An. sinensis efficacy on Plasmodium vivax transmission. An. sinensis was not stringently refractory to P. falciparum under experimental conditions, however, sporozoite was not found in salivary glands of field collected An. sinensis. The literature on An. sienesis biology and bionomics was abundant, but molecular studies, such as gene functions and mechanisms, were limited. Only 12 molecules (genes, proteins or enzymes) have been studied. In addition, there were considerable untapped omics resources for potential vector control tools. Existing information on An. sienesis could serve as a baseline for advanced research on biology, bionomics and genetics relevant to vector control strategies.