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Wuhan City (WH) in China was the first place to report COVID-19 in the world and the outbreak of COVID-19 was controlled in March of 2020 in WH. It is unclear what percentage of people were infected with SARS-CoV-2 and what percentage of population is carriers of SARS-CoV-2 in WH. We retrospectively analyzed the SARS-CoV-2 IgG and IgM antibody positive rates in 63,107 healthy individuals from WH and other places of China using commercial colloidal gold detection kits from March 6 to May 3, 2020. Statistical approaches were utilized to explore the difference and correlation for the seropositive rate of IgG and IgM antibody on the basis of sex, age group, geographic region and detection date. The total IgG and IgM antibody positive rate of SARS-CoV-2 was 1.68% (186/11,086) in WH, 0.59% (226/38,171) in Hubei Province without Wuhan (HB), and 0.38% (53/13,850) in the nation except for Hubei Province (CN), respectively. The IgM positive rate was 0.46% (51/11,086) in WH, 0.13% (51/38,171) in HB, and 0.07% (10/13,850) in CN. The incidence of IgM positive rates in healthy individuals increased from March 6 to May 3, 2020 in WH. Female and older age had a higher probability of becoming infected than males (OR = 1.34; 95% CI: 1.08–1.65) or younger age (OR = 2.25; 95% CI: 1.06–4.78). The seroprevalence of SARS-CoV-2 was relatively low in WH and other places of China, but it is significantly high in WH than other places of China; a large amount of asymptomatic carriers of SARS-CoV-2 existed after elimination of clinical cases of COVID-19 in Wuhan City. Therefore, SARS-CoV-2 may exist in a population without clinical cases for a long period., Author summary Our study has investigated 63,107 healthy individuals from Wuhan City and other places in China to analyze the seroprevalence of SARS-CoV-2, which was correlated with geographic region, age, sex and the detection time. The seroprevalence of SARS-CoV-2 was relatively low in WH (1.68%, 186/11,086) and other places of China (0.38%, 53/13,850), but the seroprevalence is significantly higher in Wuhan City than other cities and other places in China. Moreover, the antibody positive rate was higher in regions closer to Wuhan City. The results of binary logistic regression model showed that the higher seroprevalence was observed among older individuals and females had a higher probability of being infected than males.

Currently, Zika virus (ZIKV) is spreading across the world and no ZIKV infection cases have ever been reported in China. Here, we aimed to determine whether ZIKV infection exists in China. Blood samples of 273 healthy individuals were collected from Nanning City, Guangxi Province, China in March 2019. We found that 9.5% (26/273) and 1.8% (5/273) of healthy persons were positive to ZIKV total antibody (IgG and/or IgM) IgM antibody, respectively. All ZIKV positive plasma samples were negative to Dengue virus and West Nile virus. Among the ZIKV antibody positive plasma samples, 65.4% (17/26) exhibited neutralizing activity to ZIKV. Followed up studies showed that none had clinical symptoms of ZIKV infection and oversea experience. Together, our study indicates that endemic ZIKV infections emerge in China, which not only suggested that ZIKV posed a potential threat to public health in China, but also expand the ZIKV epidemic areas in East and Southeast Asia., Author summary ZIKA, caused by mosquito-borne Zika virus (ZIKV), is typically asymptomatic or with mild fever, and the occurrence of ZIKV infections are reported around the world. However, limited ZIKV epidemiological investigation was performed and no ZIKV infection cases were ever reported in China. Here, we observed that Zika virus also distributes in China. This work not only suggests ZIKV as a potential threat to public health in China but also expands our knowledge of ZIKV epidemic regions in East and Southeast Asia. Therefore, government officials, physicians and public health workers in China need to pay attention to ZIKV infection cases.

Bartonella species are emerging human pathogens. Bats are known to carry diverse Bartonella species, some of which are capable of infecting humans. However, as the second largest mammalian group by a number of species, the role of bats as the reservoirs of Bartonella species is not fully explored, in term of their species diversity and worldwide distribution. China, especially Northern China, harbors a number of endemic insectivorous bat species; however, to our knowledge, there are not yet studies about Bartonella in bats in China. The aim of the study was to investigate the prevalence and genetic diversity of Bartonella species in bats in Northern China. Bartonella species were detected by PCR amplification of gltA gene in 25.2% (27/107) bats in Mengyin County, Shandong Province of China, including 1/3 Rhinolophus ferrumequinum, 2/10 Rhinolophus pusillus, 9/16 Myotis fimbriatus, 1/5 Myotis ricketti, 14/58 Myotis pequinius. Phylogenetic analysis showed that Bartonella species detected in bats in this study clustered into ten groups, and some might be novel Bartonella species. An association between Bartonella species and bat species was demonstrated and co-infection with different Bartonella species in a single bat was also observed. Our findings expanded our knowledge on the genetic diversity of Bartonella in bats, and shed light on the ecology of bat-borne Bartonella species.