Schistosome japonicum remains one main public concern in China. This is exemplified in the hilly region in Anhui Province, where rodents have served as reservoirs for the parasite and no effective intervention could target such wild animals. The closer relationship between the hilly region and the near marshland induces the worry of spread of the hill parasite to the marshland region. Therefore, the level of snail-parasite compatibility between the hill parasite and snail populations from the Yangtze River valley was investigated. The results of this study demonstrated that both the hill (Shitai, Anhui) and the marshland (Wuxi, Jiangsu) strains of parasite were more infective to the marshland strains of snail (Zongyang and Hexian, Anhui) than to the hill strain of snail (Shitai, Anhui). When snails were individually exposed to one single miracidium, the longest prepatent period for cercarial development was observed in the combination of Shitai schistosome/Shitai snail. A nocturnal cercarial emergence pattern was observed for the hill parasite, either harbored in the hill or the marshland strain of snails. The results suggested a high compatibility between the marshland strains of snail and both the hill and the marshland strains of parasite. This would have practical implications. Moreover, the fact of the lower compatible relationship between the hill parasite and its local intermediate hosts warranted more studies.

BackgroundSchistosomiasis japonica has been resurging in certain areas of China where its transmission was previously well controlled or interrupted. Several factors may be contributing to this, including mobile populations, which if infected, may spread the disease. A wide range of estimates have been published for S. japonicum infections in mobile populations, and a synthesis of these data will elucidate the relative risk presented from these groups.MethodsA literature search for publications up to Oct 31, 2014 on S. japonicum infection in mobile populations in previously endemic but now non-endemic regions was conducted using four bibliographic databases: China National Knowledge Infrastructure, WanFang, VIP Chinese Journal Databases, and PubMed. A meta-analysis was conducted by pooling one arm binary data with MetaAnalyst Beta 3.13. The protocol is available on PROSPERO (No. CRD42013005967).ResultsA total of 41 studies in Chinese met the inclusion criteria, covering seven provinces of China. The time of post-interruption surveillance ranged from the first year to the 31st year. After employing a random-effects model, from 1992 to 2013 the pooled seroprevalence ranged from 0.9% (95% CI: 0.5-1.6%) in 2003 to 2.3% (95% CI: 1.5-3.4) in 1995; from the first year after the disease had been interrupted to the 31st year, the pooled seroprevalence ranged from 0.6% (95% CI: 0.2-2.1%) in the 27th year to 4.0% (95%CI: 1.3-11.3%) in the second year. The pooled seroprevalence in mobile populations each year was significantly lower than among the residents of endemic regions, whilst four papers reported a lower level of infection in the mobile populations than in the local residents out of only 13 papers which included this data.ConclusionsThe re-emergence of S. japonicum in areas which had previously interrupted transmission might be due to other factors, although risk from re-introduction from mobile populations could not be excluded.

Schistosomiasis japonicum is one of the most important human parasitic diseases, and a number of studies have recently elucidated the difference in biological characteristics of S. japonicum among different parasite isolates, for example, between the field and the laboratory isolates. Therefore, the understanding of underlying genetic mechanism is of both theoretical and practical importance. In this study, we used six microsatellite markers to assess genetic diversity, population structure, and the bottleneck effect (a sharp reduction in population size) of two parasite populations, one field and one laboratory. A total of 136 S. japonicum cercariae from the field and 86 from the laboratory, which were genetically unique within single snails, were analyzed. The results showed bigger numbers of alleles and higher allelic richness in the field parasite population than in the laboratory indicating lower genetic diversity in the laboratory parasites. A bottleneck effect was detected in the laboratory population. When the field and laboratory isolates were combined, there was a clear distinction between two parasite populations using the software Structure. These genetic differences may partially explain the previously observed contrasted biological traits.

Background. Although the prevention of mother-to-child transmission of syphilis program in China has achieved national coverage for 7 years, controversy still exists regarding the treatment of syphilis and the serological significance of syphilis. Objective. To explore the occurrence and influencing factors of adverse pregnancy outcomes among pregnant women with syphilis in Changzhou from 2015-2019 and to further analyze the impact of syphilis serologic titers on perinatal outcomes and neonatal serologic outcomes. Methods. Syphilis-infected pregnant women reported in Changzhou City from 2015 to 2019 were selected as the study population (data were obtained from the “China Information System for Prevention of Mother-to-child Transmission of AIDS, Syphilis and Hepatitis B.” Demographic characteristics, laboratory tests, and medication were collected to describe adverse pregnancy outcomes and the distribution of non-pale leptospiral antibody titers during pregnancy. Multivariate logistic regression was used to analyze the factors influencing adverse pregnancy outcomes. We also compared differences in syphilis titers among mothers who received different interventions, differences in serologic outcomes of their children, and correlations between them. Results. For mothers with syphilis infection, we found no treatment during pregnancy (OR =1.70) and an initial titer greater than 1 : 8 (OR =2.28) to be risk factors. For treated pregnant women, increasing age (OR =1.08), lack of standardized treatment (OR =1.87), and initial titer greater than 1 : 8 (OR =1.69) were risk factors, while previous parity was a protective factor (OR =0.62). For untreated pregnant women, marital status (OR =2.40) and initial titers greater than 1 : 8 (OR =3.57) were risk factors. There were statistically significant differences ( P < 0.01 ) in serologic titer changes, time to antibody regression, and time to exclusion of syphilis infection in children of pregnant women with syphilis infection after receiving different interventions during pregnancy, but different time distributions of interventions had no effect on these three indicators. Conclusion. Pregnant women with syphilis should actively cooperate with their doctors in the standardized treatment of pregnancy, and doctors should also pay more attention to pregnant women with syphilis whose initial titers are greater than 1 : 8. High-quality prenatal care is a key component in interrupting mother-to-child transmission of syphilis and preventing various adverse pregnancy outcomes. The adaptation of standardized treatment protocols for pregnant women with syphilis in China is a strong proof of the progress of precision medicine.