OBJECTIVE: Previous studies on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have focused on factors that influence the achievement of negative conversion of viral RNA. This study aimed to investigate the effects of the genetic mutations in different SARS-CoV-2 strains on the negative conversion time (NCT) among imported cases in Hangzhou, Zhejiang Province, China, in order to provide valuable insights for developing targeted epidemic prevention guidelines.
METHODS: This retrospective study involved 146 imported SARS-CoV-2 cases in Hangzhou from 8 April 2021 to 11 June 2022. We compared the SARS-CoV-2-specific indicators, clinical indexes, and NCT among the wild-type (WT), Delta, and Omicron groups. Spearman correlation analysis was used to identify the correlations of NCT with mutation types/frequencies.
RESULTS: The mean age of the imported cases was 35.3 (SD: 12.3) years, with 71.92 % males and 28.08 % females. The mean cycle threshold (Ct) values of open reading frame 1ab (ORF1ab) and nucleocapsid (N) RNA were 25.17 (SD: 6.44) and 23.4 (SD: 6.76), respectively. The mutations of SARS-CoV-2 strains were mainly located in N, membrane (M), spike (S), ORF1a, ORF1b, ORF3a, ORF6, and ORF9b genes among the WT, Delta, and Omicron groups. NCT was significantly prolonged in the WT and Delta groups compared to the Omicron group. T lymphocyte, white blood cell, eosinophil, and basophil counts were dramatically higher in the WT group than the Delta group. White blood cell, red blood cell, and basophil counts were significantly lower in the Delta group than the Omicron group. Spearman correlation analysis revealed a significant correlation between the NCT of viral RNA and mutation types of viral genes of WT and Omicron strains. Additionally, NCT was markedly negatively correlated with the frequencies of five mutations in Omicron strains (ORF1b:P1223L, ORF1b:R1315C, ORF1b:T2163I, ORF3a:T223I, and ORF6:D61L).
CONCLUSIONS: This study indicates that five mutations in Omicron strains (ORF1b:P1223L/R1315C/T2163I, ORF3a:T223I and ORF6:D61L) shortened NCT in imported SARS-CoV-2 cases.

UNASSIGNED: Chikungunya is emerging and reemerging word-widely in the past decades. It is non-endemic in Zhejiang Province, Southeast China. Aedes albopictus, one of major vectors of chikungunya, is widely-distribution in Zhejiang, and autochthonous transmission is possible after introducing chikungunya virus.
UNASSIGNED: Retrospectively collected the epidemiological, clinical and genetic data of chikungunya and conducted the descriptive analysis and gene sequence analysis.
UNASSIGNED: From 2008 to 2022, 29 chikungunya cases, including 26 overseas imported and 3 local cases, were reported and no cases died of chikungunya. More than half of the imported cases (53.85%) were from Southeast Asia. Seasonal peak of the imported cases was noted between August and September, and 42.31% cases onset in those 2 months. Eight prefecture-level cities and 16 counties reported cases during the study period, with Jinghua (27.59%) and Hangzhou (24.14%) reporting the largest number of cases. The 3 local cases were all reported in Qujiang, Quzhou in 2017. For imported cases, the male-female gender ratio was 2.71:1, 20-30 years old cases (46.15%) and commercial service (42.31%) accounted for the highest proportion. Clinically, fever (100%), fatigue (94.44%), arthralgia (79.17%), headache (71.43%) and erythra (65.22%) were the most common reported symptoms. Eight whole-genome sequences were obtained and belonged to East/Central/South African (ECSA) or Asian genotype.
UNASSIGNED: With the change of immigration policy, the surveillance of chikungunya should be strengthened and the ability of the case discovery and diagnosis should be improved in Zhejiang in the post-COVID-19 era.

In 2013, an epidemic of falciparum malaria involving over 820 persons unexpectedly broke out in Shanglin County, Guangxi Zhuang Autonomous Region, China, after a large number of migrant workers returned from Ghana, where they worked as gold miners. Herein, we selected 146 isolates randomly collected from these patients to investigate the resistance characteristics of the parasite to sulfadoxine-pyrimethamine (SP) by screening mutations in the dhfr and dhps genes. All 146 isolates were successfully genotyped for dhps, and only 137 samples were successfully genotyped for dhfr. In the dhfr gene, point mutations occurred at three codons: 51 (83.2%, 114/137), 59 (94.9%, 130/137), and 108 (96.4%, 132/137). In the dhps gene, mutations occurred at four codons: 436 (36.3%, 53/146 for S436A, 0.7%, 1/146 for S436Y), 437 (95.2%, 139/146), 540 (3.4%, 5/146), and 613 (2.7%, 4/146). All 146 isolates had mutations in at least one codon, either within dhfr or dhps. Quadruple mutation I51R59N108/G437 (41.1%, 60/146) of partial or low resistance level was the most prevalent haplotype combination. Quintuple I51R59N108/G437E540 accounted for 2.1% (3/146). Sextuple I51R59N108/A436G437S613 was also found and accounted for 1.4% (2/146). A chronological assay incorporating two sets of resistance data from the studies of Duah and Amenga-Etego provided an overview of the resistance trend from 2003 to 2018. During this period, the results we obtained generally coincided with the total development tendency of SP resistance. It can be concluded that Plasmodium falciparum samples collected from Chinese migrant workers from Ghana presented prevalent but relatively partial or low resistance to SP. A chronological assay incorporating two sets of data around 2013 indicates that our results possibly reflect the SP resistance level of Ghana in 2013 and that the possibility of increased resistance exists. Therefore, reasonable drug use and management should be strengthened while also maintaining a continuous screening of resistance to SP. These findings also underscore the need to strengthen the prevention of malaria importation from overseas and focus on preventing its reintroduction and transmission in China.

BACKGROUND: The Hubei Province in China reported its last indigenous malaria case in September 2012, but imported malaria cases, particularly those related to Plasmodium vivax and Plasmodium falciparum, threaten Hubei\'s malaria-free status. This study investigated the epidemiological changes in P. vivax and P. falciparum malaria in this province to provide scientific evidence for preventing malaria resurgence.
METHODS: The prevalence, demographic characteristics, seasonal features, and geographical distribution of malaria were assessed using surveillance data and were compared across three stages: control stage (2005-2009) and elimination stages I (2010-2014) and II (2015-2019).
RESULTS: In 2005-2019, 8483 malaria cases were reported, including 5599 indigenous P. vivax cases, 275 imported P. vivax cases, 866 imported P. falciparum cases, and 1743 other cases. Imported P. falciparum cases accounted for 0.07% of all cases reported in 2005, but increased to 78.81% in 2019. Most imported P. vivax and P. falciparum malaria occurred among males, aged 21-60 years, during elimination stages I and II. The number of regions affected by imported P. falciparum and P. vivax increased markedly in Hubei from the control stage to elimination stage II. Overall, 1125 imported P. vivax and P. falciparum cases were detected from 47 other nations. Eight imported cases were detected from other provinces in China. From the control stage to elimination stage II, the number of cases of malaria imported from African countries increased, and that of cases imported from Southeast Asian countries decreased.
CONCLUSIONS: Although Hubei has achieved malaria elimination, it faces challenges in maintaining this status. Hence, imported malaria surveillance need to be strengthened to reduce the risk of malaria re-introduction.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a global threat since 2020. The emergence of the Omicron variant in 2021, which replaced Delta as the dominant variant of concern, has had a significant adverse impact on the global economy and public health. During this period, Zhejiang Province implemented dynamic zeroing and focused on preventing imported cases. This study aimed to gain clear insight into the characteristics of imported COVID-19 cases in Zhejiang Province.
We conducted a systematic molecular epidemiological analysis of 146 imported cases between July 2021 and November 2022 in Zhejiang Province. Virus samples with cycle threshold (Ct) value less than 32 were performed next generation sequencing. Basing the whole genome sequence obtained after quality control and assembly of reads, the whole genome variation map and phylogenetic tree were constructed and further analyzed.
Our study identified critical months and populations for surveillance, profiled the variation of various lineages, determined the evolutionary relationships among various lineages of SARS-CoV-2, and compared the results in Zhejiang with those obtained worldwide during this period.
The continuous molecular epidemiological surveillance of imported cases of COVID-19 in Zhejiang Province during 2021 to 2022 is consistent with the global epidemic trend.

This review aims to map the spread of the virus from Iran to the Middle East and the rest of the world and to help better understand the key trends that occurred during COVID-19 from this epidemic center. We performed a literature review which was undertaken from 16 June to 22 November 2020. We reviewed the available evidence on imported cases from Iran, in the electronic databases PubMed and Google Scholar, as well as gray literature. It is shown that 125 cases were imported from Iran, out of which most of the imported cases were asymptomatic, and PCR testing was the most common method of detection. It was also found that more than half of the imported cases were not quarantined or isolated at home. The review revealed that many countries, especially the Middle East had imported cases from Iran. The big gap between the date of arrival at the airport and the date of diagnosis emphasizes the importance of early detection and quarantine measures, to stop the spread of the virus.

During infectious disease outbreaks, inference of summary statistics characterizing transmission is essential for planning interventions. An important metric is the time-dependent reproduction number (Rt), which represents the expected number of secondary cases generated by each infected individual over the course of their infectious period. The value of Rt varies during an outbreak due to factors such as varying population immunity and changes to interventions, including those that affect individuals\' contact networks. While it is possible to estimate a single population-wide Rt, this may belie differences in transmission between subgroups within the population. Here, we explore the effects of this heterogeneity on Rt estimates. Specifically, we consider two groups of infected hosts: those infected outside the local population (imported cases), and those infected locally (local cases). We use a Bayesian approach to estimate Rt, made available for others to use via an online tool, that accounts for differences in the onwards transmission risk from individuals in these groups. Using COVID-19 data from different regions worldwide, we show that different assumptions about the relative transmission risk between imported and local cases affect Rt estimates significantly, with implications for interventions. This highlights the need to collect data during outbreaks describing heterogeneities in transmission between different infected hosts, and to account for these heterogeneities in methods used to estimate Rt. This article is part of the theme issue \'Technical challenges of modelling real-life epidemics and examples of overcoming these\'.

Coccidioidomycosis is caused by the dimorphic fungi Coccidioides species which is endemic in the Western hemisphere. Reports on the characteristics of travel-related disseminated coccidioidomycosis in immunocompetent patients are rare, especially in non-endemic regions. The multifaceted symptoms of this condition present a diagnostic challenge to clinicians. This study aimed to review immunocompetent patients diagnosed with disseminated coccidioidomycosis in a tertiary hospital in Eastern China and other non-endemic areas, and to emphasize the importance of combining travel history with clinical manifestations and proper diagnostic examinations. This study retrospectively reviewed a case series of disseminated coccidioidomycosis diagnosed in an academic hospital in Eastern China. We conducted a global literature review of disseminated coccidioidomycosis in immunocompetent patients with travel history. We identified six patients in our case series and reviewed 42 cases in the literature. Travel history included Mexico, Arizona, California, and regions of low endemicity. Extrapulmonary sites of infection, which presented with diverse signs and symptoms, involved the skin and soft tissue, musculoskeletal system, lymph nodes, and central nervous system. Misdiagnoses and diagnostic delays were common. Next-generation sequencing substantially promoted precise diagnosis in our series. The overall prognosis for immunocompetent individuals was positive, mainly benefited from long-term azole therapies. The patients that succumbed had either central nervous system involvement or multiorgan dissemination. Progressive pneumonia with varied symptoms and travel history should alert healthcare professionals in non-endemic areas to consider the possibility of Coccidioides species infection. We recommend detailed history-taking and hypothesis-free detection of pathogens for cases with diagnostic delay.

BACKGROUND: To limit the spread of COVID-19 due to imported cases, Burkina Faso has set up quarantine measures for arriving passengers. We aimed to determine the incidence and predictors of imported cases of COVID-19 in Burkina Faso.
METHODS: A prospective cohort study was performed using data from passengers arriving at the airport from April 9 to August 31, 2020. The data was extracted from the District Health Information Software 2 (DHIS2) platform. Cox regression was used to identify predictors of imported cases of COVID-19.
RESULTS: Among 6,332 travelers who arrived in the study period, 173 imported cases (2.7%) were recorded. The incidence rate was 1.9 cases per 1,000 traveler-days (95%CI: 1.6-2.2 per 1,000). Passengers arriving in April (Adjusted hazard ratio [aHR] = 3.56; 95%CI: 1.62-7.81) and May (aHR = 1.92; 95% CI: 1.18-3.12) were more at risk of being tested positive compared to those arriving in August, as well as, passengers presenting with one symptom (aHR = 3.71; 95% CI: 1.63-8.43) and at least two symptoms (aHR = 10.82; 95% CI: 5.24-22,30) compared to asymptomatic travelers.
CONCLUSIONS: The incidence of imported cases was relatively low in Burkina Faso between April and August 2020. The period of travel and the presence of symptoms at arrival predicted the risk of being tested positive to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This is essential in the context of the high circulation of virus variants worldwide and the low local capacity to perform genotyping tests to strengthen the surveillance and screening capacities at the points of entry into the country.

BACKGROUND: In March 2020, the WHO declared the novel coronavirus outbreak a global pandemic. While great success in coronavirus disease 2019 (COVID-19) control has been achieved in China, imported cases have become a major challenge. This study aimed to describe the epidemiological and clinical characteristics of imported COVID-19 cases and to assess the effectiveness of screening strategies in Beijing, China.
METHODS: This retrospective study included all imported cases transferred to Beijing Ditan Hospital from 29 February to 20 March 2020 who were screened by both chest computed tomography (CT) and reverse-transcriptase-polymerase chain reaction (RT-PCR) at the initial presentation. Demographic, clinical and laboratory data, in addition to chest CT imaging, were collected and analysed.
RESULTS: In total, 2545 cases were included, among which 71 (2.8%) were finally diagnosed with laboratory-confirmed COVID-19. The majority 63 (88.7%) were from Europe. The most common initial symptoms were cough and fever, which accounted for 49.3% and 42.3%, respectively. Only four cases (5.6%) had lymphocytopenia, and thirteen cases (18.3%) demonstrated elevated levels of C-reactive protein (CRP). All cases had normal serum levels of procalcitonin (PCT). At initial presentation, among the 71 confirmed cases, 59 (83.1%) had a positive RT-PCR assay, and 35 (49.3%) had a positive chest CT. Twelve (16.9%) had a negative RT-PCR assay but a positive chest CT.
CONCLUSIONS: A combination of RT-PCR and chest CT is an effective strategy for the screening of imported COVID-19 cases. Our findings provide important information and clinical evidence about the infection control of imported COVID-19 cases.