The ongoing pandemic of novel coronavirus disease 2019 (COVID-19) is challenging global public health system. Sex-differences in infectious diseases are a common but neglected problem. We used the national surveillance database of COVID-19 in mainland China to compared gender differences in attack rate (AR), proportion of severe and critical cases (PSCC) and case fatality rate (CFR) in relation to age, affected province, and onset-to-diagnosis interval. The overall AR was significantly higher in female population than in males (63.9 versus 60.5 per million persons; P ˂ .001). By contrast, PSCC and CFR were significantly lower among female patients (16.9% and 4.0%) than among males (19.5% and 7.2%), with ORs of 0.87 and 0.57, respectively (both P ˂ .001). The female-to-male differences were age-dependent, which were significant among people aged 50–69 years for AR, and in the patients of 30-years or older for both PSCC and CFR (all P ≤ .001). The AR, PSCC and CFR varied greatly from province to province. However, female-to-male differences in AR, PSCC and CFR were significant in the epicenter, Hubei province, where 82.2% confirmed cases and 97.4% deaths occurred. After adjusting for age, affected province and onset-to-diagnosis interval, the female-to-male difference in AR, PSCC and CFR remained significant in multivariate logistic regression analyses. We elucidate an age-dependent gender dimorphism for COVID-19, in which the females have higher susceptibility but lower severity and fatality. Further epidemiological and biological investigations are required to better understand the sex-specific differences for effective interventions.

Healthcare workers (HCWs) worldwide are putting themselves at high risks of coronavirus disease 2019 (COVID-19) by treating a large number of patients while lacking protective equipment. We aim to provide a scientific basis for preventing and controlling the COVID-19 infection among HCWs. We used data on COVID-19 cases in the city of Wuhan to compare epidemiological characteristics between HCWs and non-HCWs and explored the risk factors for infection and deterioration among HCWs based on hospital settings. The attack rate (AR) of HCWs in the hospital can reach up to 11.9% in Wuhan. The time interval from symptom onset to diagnosis in HCWs and non-HCWs dropped rapidly over time. From mid-January, the median time interval of HCW cases was significantly shorter than in non-HCW cases. Cases of HCWs and non-HCWs both clustered in northwestern urban districts rather than in rural districts. HCWs working in county-level hospitals in high-risk areas were more vulnerable to COVID-19. HCW cases working in general, ophthalmology, and respiratory departments were prone to deteriorate compared with cases working in the infection department. The AR of COVID-19 in HCWs are higher than in non-HCWs. Multiple factors in hospital settings may play important roles in the transmission of COVID-19. Effective measures should be enhanced to prevent HCWs from COVID-19 infection.

The health of the elderly is one of the major challenges in today’s ageing society. However, research on infectious diseases among the elderly is limited. This study aimed to describe the epidemiological characteristics and dynamics of infectious diseases among the elderly population aged ≥60 years in Shandong province, China. Incidence data for infectious diseases were collected from the Shandong Multi-Center Healthcare Big Data Platform from January 2013 to June 2017, which involved 550 432 elderly persons. We compared the incidence of each infectious disease and disease category, stratified by age, gender, and region. Annual percentage change (APC) was estimated using logarithmic linear regression to examine the incidence trends. Poisson regression was conducted to identify the effect of demographic factors on incidence, with incidence rate ratio (IRR) and their 95% confidence intervals (CIs) estimated. A total of 27 595 cases of 102 infectious diseases were reported during the study period, with an overall incidence of 1425.51/100 000 person-years. The most common infectious diseases were respiratory and mucocutaneous diseases among the elderly persons, with annual increases of 17.45% and 20.44%, respectively (both P<0.05). In rural areas, the incidence of respiratory, gastrointestinal, blood- and sex-transmitted, and mucocutaneous infections increased significantly, with APCs of 178.52%, 204.66%, 28.24%, 63.01%, respectively (all P<0.05). Elderly males had a higher risk of infections than that of females, with the highest IRRa of 2.94 (95% confidence interval (CI) = 2.89, 3.00) in respiratory diseases. The elderly aged 85-89 years had a much higher risk of respiratory diseases than those aged 60-64 years (IRRa = 9.85, 95%CI: 9.39, 10.33); however, the risk of blood- and sex-transmitted diseases was highest among the elderly aged 65-69 years (IRRa = 1.24, 95% CI = 1.06, 1.45). Ageing population are facing a substantial challenge on infectious diseases. More attention should be paid to infections with significant growth. Targeted strategies and measures on elderly persons in different regions and subgroups are urgently needed.

Background: Haemaphysalis longicornis is drawing attentions for its geographic invasion, extending population, and emerging disease threat. However, there are still substantial gaps in our knowledge of viral composition in relation to genetic diversity of H. longicornis and ecological factors, which are important for us to understand interactions between virus and vector, as well as between vector and ecological elements. Results: We conducted the meta-transcriptomic sequencing of 136 pools of H. longicornis and identified 508 RNA viruses of 48 viral species, 22 of which have never been reported. Phylogenetic analysis of mitochondrion sequences divided the ticks into two genetic clades, each of which was geographically clustered and significantly associated with ecological factors, including altitude, precipitation, and normalized difference vegetation index. The two clades showed significant difference in virome diversity and shared about one fifth number of viral species that might have evolved to “generalists.” Notably, Bandavirus dabieense, the pathogen of severe fever with thrombocytopenia syndrome was only detected in ticks of clade 1, and half number of clade 2-specific viruses were aquatic-animal-associated. Conclusions: These findings highlight that the virome diversity is shaped by internal genetic evolution and external ecological landscape of H. longicornis and provide the new foundation for promoting the studies on virus-vector-ecology interaction and eventually for evaluating the risk of H. longicornis for transmitting the viruses to humans and animals.

Spotted fever group rickettsiae, mainly maintained and transmitted by ticks, are important etiological agents of (re)emerging zoonotic diseases worldwide. It is of great significance to investigate spotted fever group rickettsiae in ticks in different areas for the prevention and control of rickettsioses. In this study, a total of 305 ticks were collected from wild and domestic animals in Chongqing, Guizhou, Yunnan, and Guangxi provinces of southwestern China during 2017–2019 and examined for the presence of spotted fever group rickettsiae by PCR with primers targeting the partial gltA, ompA, rrs, and htrA genes. Results showed that two spotted fever group rickettsiae species, including the pathogenic Candidatus Rickettsia jingxinensis (Rickettsiales: Rickettsiaceae) and a potential novel species Rickettsia sp. sw (Rickettsiales: Rickettsiaceae), were identified. The Ca. R. jingxinensis sequences were recovered from Rhipicephalus microplus (Ixodida: Ixodidae) and Haemaphysalis longicornis (Ixodida: Ixodidae) ticks and phylogenetically clustered with previous Ca. R. jingxinensis, Ca. R. longicornii (Rickettsiales: Rickettsiaceae), and Rickettsia sp. XY118 (Rickettsiales: Rickettsiaceae) strains. Rickettsia sp. sw was detected in Amblyomma geoemydae (Ixodida: Ixodidae) and Rh. microplus. Interestingly, as far as we know, this was the first report of Rickettsia (Rickettsiales: Rickettsiaceae) in A. geoemydae. Phylogenetic analyses indicated that this potential novel species was closely related to R. aeschlimannii (Rickettsiales: Rickettsiaceae) with gltA and ompA genes and grouped in a cluster composed of R. montanensis (Rickettsiales: Rickettsiaceae), R. raoultii (Rickettsiales: Rickettsiaceae), R. aeschlimannii, R. massiliae (Rickettsiales: Rickettsiaceae), and R. rhipicephali (Rickettsiales: Rickettsiaceae) with htrA, while formed a separate clade with rrs. The pathogenicity of Rickettsia sp. sw should be further confirmed. These results expand the knowledge of the geographical distribution and vector distribution of spotted fever group rickettsiae in China and are useful for assessing the potential public health risk.