Mapping global zoonotic niche and interregional transmission risk of monkeypox: a retrospective observational study.

BACKGROUND: Outbreaks of monkeypox have been ongoing in non-endemic countries since May 2022. A thorough assessment of its global zoonotic niche and potential transmission risk is lacking. METHODS: We established an integrated database on global monkeypox virus (MPXV) occurrence during 1958 - 2022. Phylogenetic analysis was performed to examine the evolution of MPXV and effective reproductive number (Rt) was estimated over time to examine the dynamic of MPXV transmissibility. The potential ecological drivers of zoonotic transmission and inter-regional transmission risks of MPXV were examined. RESULTS: As of 24 July 2022, a total of 49 432 human patients with MPXV infections have been reported in 78 countries. Based on 525 whole genome sequences, two main clades of MPXV were formed, of which Congo Basin clade has a higher transmissibility than West African clade before the 2022-monkeypox, estimated by the overall Rt (0.81 vs. 0.56), and the latter significantly increased in the recent decade. Rt of 2022-monkeypox varied from 1.14 to 4.24 among the 15 continuously epidemic countries outside Africa, with the top three as Peru (4.24, 95% CI: 2.89-6.71), Brazil (3.45, 95% CI: 1.62-7.00) and the United States (2.44, 95% CI: 1.62-3.60). The zoonotic niche of MPXV was associated with the distributions of Graphiurus lorraineus and Graphiurus crassicaudatus, the richness of Rodentia, and four ecoclimatic indicators. Besides endemic areas in Africa, more areas of South America, the Caribbean States, and Southeast and South Asia are ecologically suitable for the occurrence of MPXV once the virus has invaded. Most of Western Europe has a high-imported risk of monkeypox from Western Africa, whereas France and the United Kingdom have a potential imported risk of Congo Basin clade MPXV from Central Africa. Eleven of the top 15 countries with a high risk of MPXV importation from the main countries of 2022-monkeypox outbreaks are located at Europe with the highest risk in Italy, Ireland and Poland. CONCLUSIONS: The suitable ecological niche for MPXV is not limited to Africa, and the transmissibility of MPXV was significantly increased during the 2022-monkeypox outbreaks. The imported risk is higher in Europe, both from endemic areas and currently epidemic countries. Future surveillance and targeted intervention programs are needed in its high-risk areas informed by updated prediction.

Prevalence and Etiological Characteristics of Norovirus Infection in China: A Systematic Review and Meta-Analysis.

Norovirus is a common cause of sporadic cases and outbreaks of gastroenteritis worldwide, although its prevalence and the dominant genotypes responsible for gastroenteritis outbreaks remain obscure. A systematic review was conducted on norovirus infection in China between January 2009 and March 2021. A meta-analysis and beta-binomial regression model were used to explore the epidemiological and clinical characteristics of norovirus infection and the potential factors contributing to the attack rate of the norovirus outbreaks, respectively. A total of 1132 articles with 155,865 confirmed cases were included, with a pooled positive test rate of 11.54% among 991,786 patients with acute diarrhea and a pooled attack rate of 6.73% in 500 norovirus outbreaks. GII.4 was the predominant genotype in both the etiological surveillance and outbreaks, followed by GII.3 in the etiological surveillance, and GII.17 in the outbreaks, with the proportion of recombinant genotypes increasing in recent years. A higher attack rate in the norovirus outbreaks was associated with age group (older adults), settings (nurseries, primary schools, etc.) and region (North China). The nation-wide pooled positive rate in the etiological surveillance of norovirus is lower than elsewhere in the global population, while the dominant genotypes are similar in both the etiological surveillance and the outbreak investigations. This study contributes to the understanding of norovirus infection with different genotypes in China. The prevention and control of norovirus outbreaks during the cold season should be intensified, with special attention paid to and enhanced surveillance performed in nurseries, schools and nursing homes from November to March.

Mapping the global distribution of spotted fever group rickettsiae: a systematic review with modelling analysis.

BACKGROUND: Emerging and re-emerging spotted fever group (SFG) rickettsioses are increasingly recognised worldwide as threats to public health, yet their global distribution and associated risk burden remain poorly understood. METHODS: In this systematic review and modelling analysis, we mapped global distributions of all confirmed species of SFG rickettsiae (SFGR) detected in animals, vectors, and human beings, using data collected from the literature. We assessed ecological drivers for the distributions of 17 major SFGR species using machine learning algorithms, and mapped model-predicted risks. FINDINGS: Between Jan 1, 1906, and March 31, 2021, we found reports of 48 confirmed SFGR species, with 66 133 human infections worldwide, with a large spatial variation across the continents. 198 vector species were detected to carry 47 of these Rickettsia spp. (146 ticks, 24 fleas, 15 mosquitoes, six mites, four lice, two keds, and one bug). Based on model-predicted global distributions of the 17 major SFGR species, we found five spatial clusters aggregated by ecological similarity in terms of environmental and ecoclimatic features. Rickettsia felis is the leading SFGR species to which 4·4 billion (95% CI 3·8-5·3 billion) people are at risk, followed by Rickettsia conorii (3·7 billion) and Rickettsia africae (3·6 billion). INTERPRETATION: The wide spectrum of vectors is contributing substantially to the increasing incidence of SFGR infections among humans. Awareness, diagnosis, and surveillance of SFGR infections should be improved in the high-risk regions, especially in areas where human infections are underreported. FUNDING: National Key Research and Development Program of China.

Mapping the viruses belonging to the order Bunyavirales in China.

BACKGROUND: Viral pathogens belonging to the order Bunyavirales pose a continuous background threat to global health, but the fact remains that they are usually neglected and their distribution is still ambiguously known. We aim to map the geographical distribution of Bunyavirales viruses and assess the environmental suitability and transmission risk of major Bunyavirales viruses in China. METHODS: We assembled data on all Bunyavirales viruses detected in humans, animals and vectors from multiple sources, to update distribution maps of them across China. In addition, we predicted environmental suitability at the 10 km × 10 km pixel level by applying boosted regression tree models for two important Bunyavirales viruses, including Crimean-Congo hemorrhagic fever virus (CCHFV) and Rift Valley fever virus (RVFV). Based on model-projected risks and air travel volume, the imported risk of RVFV was also estimated from its endemic areas to the cities in China. RESULTS: Here we mapped all 89 species of Bunyavirales viruses in China from January 1951 to June 2021. Nineteen viruses were shown to infect humans, including ten species first reported as human infections. A total of 447,848 cases infected with Bunyavirales viruses were reported, and hantaviruses, Dabie bandavirus and Crimean-Congo hemorrhagic fever virus (CCHFV) had the severest disease burden. Model-predicted maps showed that Xinjiang and southwestern Yunnan had the highest environmental suitability for CCHFV occurrence, mainly related to Hyalomma asiaticum presence, while southern China had the highest environmental suitability for Rift Valley fever virus (RVFV) transmission all year round, mainly driven by livestock density, mean precipitation in the previous month. We further identified three cities including Guangzhou, Beijing and Shanghai, with the highest imported risk of RVFV potentially from Egypt, South Africa, Saudi Arabia and Kenya. CONCLUSIONS: A variety of Bunyavirales viruses are widely distributed in China, and the two major neglected Bunyavirales viruses including CCHFV and RVFV, both have the potential for outbreaks in local areas of China. Our study can help to promote the understanding of risk distribution and disease burden of Bunyavirales viruses in China, and the risk maps of CCHFV and RVFV occurrence are crucial to the targeted surveillance and control, especially in seasons and locations at high risk.

Human infections with neglected vector-borne pathogens in China: A systematic review.

Background: Emerging vector-borne pathogens (VBPs) pose a continuous background threat to the global health. Knowledge of the occurrence, distributions and epidemiological characteristics of VBP are lacking in many countries. Outbreaks of novel VBP are of increasing global interest including those arising in China. Methods: A systematic review of published literature was undertaken to characterize the spectrum of VBPs causing human illness in China. We searched five databases for VBP-related articles in English and Chinese published between January 1980 and June 2021, that excluded those listed in the National Notifiable Diseases Surveillance System of China. The study is registered with PROSPERO, CRD42021259540. Findings: A total of 906 articles meeting the selection criteria were included in this study. A total of 44,809 human infections with 82 species of VBPs including 40 viruses, 33 bacteria (20 Rickettsiales bacteria, eight Spirochaetales bacteria, and five other bacteria) and nine parasites, were identified in China. Rickettsiales bacteria were the most common and widely distributed pathogens with 18,042 cases reported in 33 provinces by 347 reviewed articles, followed by Spirochaetales bacteria with 15,745 cases in 32 provinces (299 articles), viruses with 8455 cases in 30 provinces (139 articles), other bacteria with 2053 cases in 19 provinces (65 articles), parasites with 514 cases in 17 provinces (44 articles), and multiple pathogens with 3626 cases in 14 provinces (23 articles). Coxiella burnetii, Bartonella henselae and Rickettsia sibirica were the most frequently reported pathogens. A total of 18 new pathogens were reported in China during this period (these also represented their first identification globally). Based on 419 articles with clinical information, a meta-analysis revealed that flu-like illness was the most common manifestation among infections with VBPs. Interpretation: This review helps improve the understanding of VBPs in China, demonstrating the need to consider a wider surveillance of VBPs in many different settings, thus helping to inform future research and surveillance efforts. Funding: Natural Science Foundation of China.

Epidemiological features of COVID-19 patients with prolonged incubation period and its implications for controlling the epidemics in China.

BACKGROUND: COVID-19 patients with long incubation period were reported in clinical practice and tracing of close contacts, but their epidemiological or clinical features remained vague. METHODS: We analyzed 11,425 COVID-19 cases reported between January-August, 2020 in China. The accelerated failure time model, Logistic and modified Poisson regression models were used to investigate the determinants of prolonged incubation period, as well as their association with clinical severity and transmissibility, respectively. RESULT: Among local cases, 268 (10.2%) had a prolonged incubation period of > 14 days, which was more frequently seen among elderly patients, those residing in South China, with disease onset after Level I response measures administration, or being exposed in public places. Patients with prolonged incubation period had lower risk of severe illness (ORadjusted = 0.386, 95% CI: 0.203-0.677). A reduced transmissibility was observed for the primary patients with prolonged incubation period (50.4, 95% CI: 32.3-78.6%) than those with an incubation period of ≤14 days. CONCLUSIONS: The study provides evidence supporting a prolonged incubation period that exceeded 2 weeks in over 10% for COVID-19. Longer monitoring periods than 14 days for quarantine or persons potentially exposed to SARS-CoV-2 should be justified in extreme cases, especially for those elderly.

Epidemiological parameters of COVID-19 and its implication for infectivity among patients in China, 1 January to 11 February 2020.

BackgroundThe natural history of disease in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remained obscure during the early pandemic.AimOur objective was to estimate epidemiological parameters of coronavirus disease (COVID-19) and assess the relative infectivity of the incubation period.MethodsWe estimated the distributions of four epidemiological parameters of SARS-CoV-2 transmission using a large database of COVID-19 cases and potential transmission pairs of cases, and assessed their heterogeneity by demographics, epidemic phase and geographical region. We further calculated the time of peak infectivity and quantified the proportion of secondary infections during the incubation period.ResultsThe median incubation period was 7.2 (95% confidence interval (CI): 6.9‒7.5) days. The median serial and generation intervals were similar, 4.7 (95% CI: 4.2‒5.3) and 4.6 (95% CI: 4.2‒5.1) days, respectively. Paediatric cases < 18 years had a longer incubation period than adult age groups (p = 0.007). The median incubation period increased from 4.4 days before 25 January to 11.5 days after 31 January (p < 0.001), whereas the median serial (generation) interval contracted from 5.9 (4.8) days before 25 January to 3.4 (3.7) days after. The median time from symptom onset to discharge was also shortened from 18.3 before 22 January to 14.1 days after. Peak infectivity occurred 1 day before symptom onset on average, and the incubation period accounted for 70% of transmission.ConclusionThe high infectivity during the incubation period led to short generation and serial intervals, necessitating aggressive control measures such as early case finding and quarantine of close contacts.