Epidemiology of Imported Infectious Diseases, China, 2005-2016

Clinical and epidemiological features of imported loiasis in Beijing: a report from patients returned from Africa

BACKGROUND

Loiasis is one of the significant filarial diseases for people living in West and Central Africa with wide endemic area but is not seen in China. As economy booms and international traveling increase, China faces more and more imported parasitic diseases that are not endemic locally. Loiasis is one of the parasitic diseases that enter China by travelers infected in Africa. The better understanding of the clinical and laboratory features of loa loa infection will facilitate the diagnosis and treatment of loiasis in China.

METHODS

The study targeted travelers who were infected with L. loa in endemic Africa regions and returned to Beijing between 2014 and 2023. Epidemiological, clinical, and biological data as well as treatment of these patients were collected.

RESULTS

Total 21 cases were identified as L. loa infection based on their typical clinical manifestations and parasite finding. All cases had a history of travel to Africa for more than 6 months, most of them are the construction workers dispatched to West Africa with outdoor activities. Calabar swelling (n = 19; 90.5%) and pruritus (n = 11; 52.4%) were among the most common clinical symptoms followed by muscle pain (n = 7; 33.3%) and skin rash (n = 2; 9.5%). The adult worms were observed in the eyelid or subconjunctiva (n = 2; 9.5%) and subcutaneous tissues (n = 2; 9.5%). Although all patients presented with a high eosinophil count (> 0.52 × 109/L), only two cases displayed microfilariae in fresh venous blood and positive for filarial antigen. A cut section of adult worm was observed through biopsy on a skin nodule surrounded by lymphocytes, plasma cells and eosinophils. All subjects were positive in PCR targeting L. loa ITS-1. The constructed phylogenetic tree based on the amplified ITS-1 sequences identified their genetical relation to the L. Loa from Africa. All patients treated with albendazole and diethylcarbamazine were recovered without relapse.

CONCLUSION

This study provides useful information and guideline for physicians and researchers in non-endemic countries to diagnose and treat loiasis and L. loa infections acquired from endemic regions.

Forecasting and mapping dengue fever epidemics in China: a spatiotemporal analysis

BACKGROUND

Dengue fever (DF) has emerged as a significant public health concern in China. The spatiotemporal patterns and underlying influencing its spread, however, remain elusive. This study aims to identify the factors driving these variations and to assess the city-level risk of DF epidemics in China.

METHODS

We analyzed the frequency, intensity, and distribution of DF cases in China from 2003 to 2022 and evaluated 11 natural and socioeconomic factors as potential drivers. Using the random forest (RF) model, we assessed the contributions of these factors to local DF epidemics and predicted the corresponding city-level risk.

RESULTS

Between 2003 and 2022, there was a notable correlation between local and imported DF epidemics in case numbers (r = 0.41, P < 0.01) and affected cities (r = 0.79, P < 0.01). With the increase in the frequency and intensity of imported epidemics, local epidemics have become more severe. Their occurrence has increased from five to eight months per year, with case numbers spanning from 14 to 6641 per month. The spatial distribution of city-level DF epidemics aligns with the geographical divisions defined by the Huhuanyong Line (Hu Line) and Qin Mountain-Huai River Line (Q-H Line) and matched well with the city-level time windows for either mosquito vector activity (83.59%) or DF transmission (95.74%). The RF models achieved a high performance (AUC = 0.92) when considering the time windows. Importantly, they identified imported cases as the primary influencing factor, contributing significantly (24.82%) to local DF epidemics at the city level in the eastern region of the Hu Line (E-H region). Moreover, imported cases were found to have a linear promoting impact on local epidemics, while five climatic and six socioeconomic factors exhibited nonlinear effects (promoting or inhibiting) with varying inflection values. Additionally, this model demonstrated outstanding accuracy (hitting ratio = 95.56%) in predicting the city-level risks of local epidemics in China.

CONCLUSIONS

China is experiencing an increasing occurrence of sporadic local DF epidemics driven by an unavoidably higher frequency and intensity of imported DF epidemics. This research offers valuable insights for health authorities to strengthen their intervention capabilities against this disease.

Epidemiological Characteristics of Overseas-Imported Infectious Diseases Identified through Airport Health-Screening Measures: A Case Study on Fuzhou, China

BACKGROUND

This study aimed to examine the epidemiological characteristics of imported infections and assess the effectiveness of border health screening in detecting imported diseases.

METHODS

We obtained infection data for 2016 to 2019 from the Fuzhou Changle International Airport Infection Reporting System. The demographic, temporal, and spatial characteristics of travel-related infections were analyzed using r×c contingency tables, the Cochran-Armitage trend test, and seasonal-trend decomposition using LOESS (STL). Detection rates were used as a proxy for the effectiveness of border health-screening measures.

RESULTS

Overall, 559 travel-related infections were identified during the study period, with 94.3% being imported infections. Airport health screening demonstrated an overall effectiveness of 23.7% in identifying travel-associated infections. Imported infections were predominantly identified in males, with 55.8% of cases occurring in individuals aged 20-49. The peak periods of infection importation were from January to February and from May to August. The infectious diseases identified were imported from 25 different countries and regions. All dengue fever cases were imported from Southeast Asia. Most notifiable infections (76.0%) were identified through fever screening at the airport.

CONCLUSION

The increasing number of imported infections poses a growing challenge for public health systems. Multifaceted efforts including surveillance, vaccination, international collaboration, and public awareness are required to mitigate the importation and spread of infectious diseases from overseas sources.

Nine years of imported malaria in a teaching hospital in Belgium: Demographics, clinical characteristics, and outcomes

BACKGROUND

Imported malaria is often misdiagnosed due to the aspecific symptoms and lack of familiarity among clinicians. This study aims to evaluate a decade-long trend of imported malaria cases in a Belgian teaching hospital by analyzing demographics, clinical characteristics, and outcomes.

METHODS

Medical records of 223 patients with confirmed malaria diagnoses between 2010 and 2019 were analyzed.

RESULTS

Most patients were male (63.2%), aged 18-65 years (77.1%), and visiting friends or relatives (40.8%). Central Africa was the most common travel destination (54.3%), and 63.7% did not take prophylaxis. Symptoms were flu-like, with fever (91.9%) being most prevalent. P. falciparum was identified in 88.3% of cases. A high proportion of severe cases (41.7%) and a low mortality rate (0.9%) were recorded. A severe form of the disease is associated with a more extended hospital stay than uncomplicated form (median of 5 vs. 4 days, p < 0.001). Thirty-five-point five percent [33/93] of patients with severe malaria have had a previous malaria infection compared to 50.8% [66/130] of uncomplicated patients (p= 0.013) wich was statistically significant.

CONCLUSION

Malaria disproportionately affects VFRs traveling to Central Africa, and flu-like symptoms should raise suspicion. Prophylaxis is essential to prevent the disease, and early diagnosis is critical for effective management. A severe form of the disease is associated with a more extended hospital stay than uncomplicated form and people with a previous history of malaria have a less severe disease.

The epidemiology of Aedes-borne arboviral diseases in Zhejiang, Southeast China: a 20 years population-based surveillance study

Objective

Aedes-borne arboviral diseases were important public health problems in Zhejiang before the coronavirus disease 2019 (COVID-19) pandemic. This study was conducted to investigate the characteristics and change of the epidemiology of Aedes-borne arboviral diseases in the province.

Methods

Descriptive analyses were conducted to summarize the epidemiology of Aedes-borne arboviral diseases during 2003-2022.

Results

A total of 3,125 cases, including 1,968 indigenous cases, were reported during 2003-2022. Approximately three-quarters of imported cases were infected from Southeast Asia. The number of annual imported cases increased during 2013-2019 (R2 = 0.801, p = 0.004) and peaked in 2019. When compared with 2003-2012, all prefecture-level cities witnessed an increase in the annual mean incidence of imported cases in 2013-2019 (0.11-0.42 per 100,000 population vs. 0-0.05 per 100,000 population) but a drastic decrease during 2020-2022 (0-0.03 per 100,000 population). The change in geographical distribution was similar, with 33/91 counties during 2003-2012, 86/91 during 2013-2019, and 14/91 during 2020-2022. The annual mean incidence of indigenous cases in 2013-2019 was 7.79 times that in 2003-2012 (0.44 vs. 0.06 per 100,000 population). No indigenous cases were reported between 2020-2022. Geographical extension of indigenous cases was also noted before 2020-from two counties during 2003-2012 to 44 during 2013-2019.

Conclusion

Dengue, chikungunya fever, zika disease, and yellow fever are not endemic in Zhejiang but will be important public health problems for the province in the post-COVID-19 era.

Epidemiological Characteristics and Economic Burden of Dengue in Zhejiang Province, China

Dengue imposes a heavy economic burden on families and society. We used surveillance data reported in 2019 to characterize the dengue epidemic in Zhejiang Province, China, which provided guidance for dengue prevention and control. Dengue epidemics mostly occurred in July to October. People aged 30-44 years, males, and commercial service workers were more likely to suffer from dengue. The epidemic areas were mainly in Hangzhou and Wenzhou. Meanwhile, we assessed the economic cost of dengue in the province from both family and organizational perspectives. The direct economic burden of dengue patients was estimated to be USD 405,038.25, and the indirect economic burden was USD 140,364.90, for a total economic burden of USD 543,213.00. The direct economic burden of dengue patients should be reduced by increasing the coverage and reimbursement of health insurance. Additionally, the total annual cost of dengue prevention and control for the government and organizational sectors was estimated to be USD 7075,654.83. Quantifying the dengue burden is critical for developing disease control strategies, allocating public health resources, and setting health policy priorities.

Constructing an emergency preparedness evaluation index system for public use during major emerging infectious disease outbreaks: a Delphi study

BACKGROUND

The major emerging infectious diseases (MEIDs) have occurred frequently and become increasingly serious in the world. Sufficient personal emergency preparedness is critical for the general people in efficiently responding to and recovering from MEIDs. Nevertheless, few specific indicators are available for assessing the individual emergency preparedness of the general public during these periods. Therefore, the aim of this study was to construct an index system for comprehensively evaluating the personal emergency preparedness of the public regarding MEIDs.

METHODS

Based on the global national-level emergency preparedness index framework and a literature review, a preliminary index system was constructed. From June 2022 to September 2022, a panel of 20 experts from nine provinces and municipalities across multiple research areas participated in this Delphi study. They rated the importance of pre-defined indicators using a five-point Likert scale and provided their qualitative comments. According to the feedback of each round of experts, the indicators of the evaluation index system were revised.

RESULTS

After two rounds of expert consultation the evaluation index system reached a consensus, containing five first-level indicators, cooperating with prevention and control work, improving emergency response capacity, securing supplies and equipment, preparing economic resources, maintaining physical and mental health with affiliated 20 s-level indicators and 53 third-level indicators. The expert authority coefficient of consultation was 0.88 and 0.90. The Kendall's coefficient of concordance of expert consultations was 0.294 and 0.322, respectively. The differences were statistically significant (P < 0.05).

CONCLUSION

A valid, reliable and scientific evaluation index system was established. This personal emergency preparedness index system, as a precursor form, will further lay the foundation for the formation of an assessment instrument. At the same time, it could provide a reference for future education and training of emergency preparedness for the general public.

Northern and Central Chile still free of emerging flaviviruses in mosquitoes (Diptera: Culicidae)

Geographic isolation and strict control limits in border areas have kept Chile free from various pathogens, including Flavivirus. However, the scenario is changing mainly due to climate change, the reintroduction of more aggressive mosquitoes, and the great wave of migration of people from endemic countries in recent years. Hence, it is necessary to surveillance mosquitoes to anticipate a possible outbreak in the population and take action to control it. This study aimed to investigate the presence of Flavivirus RNA by molecular tools with consensus primers in mosquitoes collected in the extreme north and central Chile. From 2019 to 2021, a prospective study was carried out in localities of Northern and part of Central Chile. Larvae, pupae, and adults of mosquitoes were collected in rural and urban sites in each locality. The collected samples were pooled by species and geographical location and tested using RT-PCR and RT-qPCR to determine presence of Flavivirus. 3085 specimens were collected, the most abundant specie Culex quinquefasciatus in the North and Aedes (Ochlerotatus) albifasciatus in the Center of Chile. Both genera are associated with Flavivirus transmission. However, PCR and RT-PCR did not detect Flavivirus RNA in the mosquitoes studied. These negative results indicate we are still a free Flavivirus country, which is reaffirmed by the non-existence of endemic human cases. Despite this, routine surveillance of mosquitoes and the pathogens they carry is highly recommended to evaluate each area-specific risk of vector-borne transmission.

How can imported monkeypox break the borders? A rapid systematic review

BACKGROUND

Monkeypox was designated as an emerging illness in 2018 by the World Health Organization Research and Development Blueprint, necessitating expedited research, development, and public health action. In this review, we aim to shed the light on the imported cases of monkeypox in attempt to prevent the further spread of the disease. Methodology An electronic search in the relevant database (Web of Science, PubMed Medline, PubMed Central, Google scholar, and Embase) was conducted to identify eligible articles. In addition to searching the grey literature, manual searching was carried out using the reference chain approach.

RESULTS

A total of 1886 articles were retrieved using the search strategy with 21 studies included in the systematic review. A total of 113 cases of imported monkeypox were confirmed worldwide. Nineteen patients mentioned a travel history from Nigeria, thirty-eight infected cases had travel destinations from Europe, fifty-four cases traveled from European countries such as; Spain, France, and the Netherlands, one case from Portugal, and another one from the United Kingdom (UK). All reported clades of the virus were West African clade. Nine studies showed the source of infection was sexual contact, especially with male partners. Six studies mentioned the cause of infection was contact with an individual with monkeypox symptoms. Two studies considered cases due to acquired nosocomial infection. Ingestion of barbecued bushmeat was the source of infection in three studies and rodent carcasses were the source of infection in the other two studies.

CONCLUSION

The development of functioning surveillance systems and point-of-entry screening is essential for worldwide health security. This necessitates ongoing training of front-line health professionals to ensure that imported monkeypox is properly diagnosed and managed. In addition, implementing effective health communication about monkeypox prevention and control is mandatory to help individuals to make informed decisions to protect their own and their communities' health.

Epidemiological characteristics of imported acute infectious diseases in Guangzhou, China, 2005-2019

BACKGROUND

The global spread of infectious diseases is currently a prominent threat to public health, with the accelerating pace of globalization and frequent international personnel intercourse. The present study examined the epidemiological characteristics of overseas imported cases of acute infectious diseases in Guangzhou, China.

METHODS

We retrospectively investigated the distribution of diseases, demographic characteristics, and temporal and spatial variations of imported cases of acute infectious diseases in Guangzhou based on the surveillance data of notifiable infectious diseases from 2005 to 2019, provided by Guangzhou center for Disease Control and Prevention. The Cochran-Armitage trend test was applied to examine the trend in the number of imported cases over time.

RESULTS

A total of 1,025 overseas imported cases of acute infectious diseases were identified during the study period. The top three diseases were dengue (67.12%), malaria (12.39%), and influenza A (H1N1) pdm09 (4.10%). Imported cases were predominantly males, with a sex ratio of 2.6: 1 and 75.22% of the cases were those aged 20-49 years. Businessmen, workers, students and unemployed persons accounted for a large proportion of the cases (68.49%) and many of the cases came from Southeast Asia (59.02%). The number of imported cases of acute infectious diseases increased during the study period and hit 318 in 2019. A clear seasonal pattern was observed in the number of imported cases with a peak period between June and November. Imported cases were reported in all of the 11 districts in Guangzhou and the central districts were more seriously affected compared with other districts.

CONCLUSIONS

The burden of dengue imported from overseas was substantial and increasing in Guangzhou, China, with the peak period from June to November. Dengue was the most common imported disease. Most imported cases were males aged 20-49 years and businessmen. Further efforts, such as strengthening surveillance of imported cases, paying close attention to the epidemics in hotspots, and improving the ability to detect the imported cases from overseas, are warranted to control infectious diseases especially in the center of the city with a higher population density highly affected by imported cases.

The imported infections among foreign travelers in China: an observational study

BACKGROUND

In the past few decades, globalization has rendered more frequent and intensive population movement between countries, which has changed the original disease spectrum and brought a huge health impact on the global population including China. This study aims to describe the spectrum and epidemiological characteristics of imported infections among foreign travelers travelling to China.

METHODS

The data on imported infections among foreign travelers were obtained from Custom Inbound Screening System (CISS) and the National Notifiable Infectious Disease Reporting System (NNIDRS). All the infections were classified into respiratory, gastrointestinal, vector-borne, blood/sex-transmitted and mucocutaneous diseases, of which case numbers and incidences were calculated and the proportions were compared among subgroups.

RESULTS

In total, 17,189 travelers diagnosed with 58 imported infectious diseases were reported from 2014 to 2018, with an overall incidence of 122.59 per million. Respiratory infection (7,351 cases, mainly influenza) and blood/sex-transmitted diseases (6,114 cases mainly Hepatitis B and HIV infection) were the most frequently diagnosed diseases, followed by vector-borne infections (3,128 cases, mainly dengue fever and malaria). The highest case number was from Asia and Europe, while the highest incidence rate was from Africa (296.00 per million). When specific diagnosis was compared, both the highest absolute case number and incidence were observed for influenza. An obvious seasonal pattern was observed for vector-borne diseases, with the annual epidemic spanning from July to November. The origin-destination matrices disclosed the movement of imported infection followed specific routes.

CONCLUSIONS

Our study provided a profile of infectious diseases among foreign travelers travelling to China and pinpointed the target regions, seasons and populations for prevention and control, to attain an informed control of imported infections in China.

Biochemical characteristics of patients with imported malaria

Objectives

This study aimed to investigate the clinical and biochemical profiles of patients with imported malaria infection between 1 January 2011 and 30 April 2022 and admitted to the Fourth People’s Hospital of Nanning.

Methods

This cohort study enrolled 170 patients with conformed imported malaria infection. The clinical and biochemical profiles of these participants were analyzed with malaria parasite clearance, and signs and symptoms related to malaria disappearance were defined as the primary outcome. A multivariable logistic regression model was used to evaluate the odds ratios (ORs) with 95% confidence intervals (CIs) for cerebral malaria. The Cox model was used to estimate the hazard ratios (HRs) with 95% CIs for parasite clearance.

Results

Adenosine deaminase and parasitemia were found to be independent risk factors for severe malaria in patients with imported malaria (OR = 1.0088, 95% CI: 1.0010–1.0167, p = 0.0272 and OR = 2.0700, 95% CI: 1.2584–3.4050, p = 0.0042, respectively). A 0.5–standard deviation (SD) increase of variation for urea (HR = 0.6714, 95% CI: 0.4911–0.9180), a 0.5-SD increase of variation for creatinine (HR = 0.4566, 95% CI: 0.2762–0.7548), a 0.25-SD increase of variation for albumin (HR = 0.4947, 95% CI: 0.3197–0.7653), a 0.25-SD increase of variation for hydroxybutyrate dehydrogenase (HR = 0.6129, 95% CI: 0.3995–0.9402), and a 1.0-SD increase of variation for ferritin (HR = 0.5887, 95% CI: 0.3799–0.9125) were associated with a higher risk for increased parasite clearance duration than a low-level change.

Conclusions

Aspartate aminotransferase, urea, creatinine, albumin, hydroxybutyrate dehydrogenase, and ferritin are useful biochemical indicators in routine clinical practice to evaluate prognosis for imported malaria.

Survival and Replication of Zika Virus in Diapause Eggs of Aedes Albopictus From Beijing, China

Zika virus (ZIKV) has emerged as a globally important arbovirus. The virus is primarily transmitted to humans through the bite of an infective Aedes albopictus in temperate area. Vertical transmission of ZIKV by Ae. albopictus is determined and has been suggested to be a means by which the virus could persist in nature. Ae. albopictus undergoes a well-characterized photoperiodic diapause. Viruses are harbored by overwintering mosquitoes in diapause that contributes to the resurgence of vertebrate diseases in the following spring, yet little is known about the impact of diapause on the regulation of viral replication and survival. The purpose of this study is to determine that Ae. albopictus in Beijing are highly susceptible to ZIKV (92.3%), and viable virus is passed to their organs of progeny via vertical transmission. Moreover, diapause eggs (diapause incidence 97.8%) had significantly lower minimum infection rates and filial infection rates of the first gonotrophic cycle than those of the second gonotrophic cycle in the short-day photoperiod group. Regarding the development of diapause eggs, the minimum infection rates and ZIKV RNA copy number increased significantly, suggesting that virus RNA replication occurred in the diapause eggs. Meanwhile, eggs from the ZIKV-infected mosquitoes had a significantly lower hatching rate compared with uninfected mosquitoes, implying an intriguing interaction between diapause eggs and virus. The findings here suggest that vertical transmission of ZIKV from diapause eggs to progeny may have a critical epidemiological role in the dissemination and maintenance of ZIKV circulating in the vector.

Investigation of the understanding on tropical infectious diseases and oral health among dental professionals in China

Background

With the increasing exchange of domestic and international personnel, local infections of tropical infectious diseases are continuing in tropics and imported infections are emerging in non-tropics, some of which are accompanied by oral manifestations. Therefore, it is essential for dental professionals to identify the related oral manifestations, who are working for domestic medical service, international medical assistance, peace-keeping medical service or medical support of international joint military exercises. This study aims to investigate the attitude and knowledge of Chinese dental professionals on tropical infectious diseases and oral health, and to explore the difference between different genders, education backgrounds, professional identities, professional titles and tropics working experience.

Methods

Network questionnaire was used to evaluate the knowledge and attitude of 236 Chinese dental professionals towards tropical infectious diseases and oral health.

Results

The scores of the participants on tropical infectious diseases and oral health were quite low. Although working experience in the tropics partially affected the understanding, there was no difference between different genders, education backgrounds, professional identities and professional titles.

Conclusion

The understanding of dental professionals on tropical infectious diseases and oral health was insufficient. It is necessary to improve the clinical education and management specified with tropical infectious diseases and oral health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02250-x.

Epidemiology of Indigenous Dengue Cases in Zhejiang Province, Southeast China

Objective

Autochthonous transmission of the dengue virus (DENV) occurred each year from 2014 to 2018 in Zhejiang province, and became an emerging public health problem. We characterized the autochthonous transmission of the DENV and traced the source of infection for further control and prevention of dengue.

Methods

Descriptive and spatiotemporal cluster analyses were conducted to characterize the epidemiology of autochthonous transmission of the DENV. Molecular epidemiology was used to identify the infection source.

Results

In total, 1,654 indigenous cases and 12 outbreaks, with no deaths, were reported during 2004–2018. Before 2017, all outbreaks occurred in suburban areas. During 2017–2018, five out of eight outbreaks occurred in urban areas. The median duration of outbreaks (28 days) in 2017–2018 was shortened significantly (P = 0.028) in comparison with that in 2004–2016 (71 days). The median onset-visiting time, visiting-confirmation time, and onset-confirmation time was 1, 3, and 4 days, respectively. The DENV serotypes responsible for autochthonous transmission in Zhejiang Province were DENV 1, DENV 2, and DENV 3, with DENV 1 being the most frequently reported. Southeast Asia was the predominant source of indigenous infection.

Conclusions

Zhejiang Province witnessed an increase in the frequency, incidence, and geographic expansion of indigenous Dengue cases in recent years. The more developed coastal and central region of Zhejiang Province was impacted the most.

Profile and dynamics of infectious diseases: a population-based observational study using multi-source big data

Background

The current surveillance system only focuses on notifiable infectious diseases in China. The arrival of the big-data era provides us a chance to elaborate on the full spectrum of infectious diseases.

Methods

In this population-based observational study, we used multiple health-related data extracted from the Shandong Multi-Center Healthcare Big Data Platform from January 2013 to June 2017 to estimate the incidence density and describe the epidemiological characteristics and dynamics of various infectious diseases in a population of 3,987,573 individuals in Shandong province, China.

Results

In total, 106,289 cases of 130 infectious diseases were diagnosed among the population, with an incidence density (ID) of 694.86 per 100,000 person-years. Besides 73,801 cases of 35 notifiable infectious diseases, 32,488 cases of 95 non-notifiable infectious diseases were identified. The overall ID continuously increased from 364.81 per 100,000 person-years in 2013 to 1071.80 per 100,000 person-years in 2017 (χ² test for trend, P < 0.0001). Urban areas had a significantly higher ID than rural areas, with a relative risk of 1.25 (95% CI 1.23–1.27). Adolescents aged 10–19 years had the highest ID of varicella, women aged 20–39 years had significantly higher IDs of syphilis and trichomoniasis, and people aged ≥ 60 years had significantly higher IDs of zoster and viral conjunctivitis (all P < 0.05).

Conclusions

Infectious diseases remain a substantial public health problem, and non-notifiable diseases should not be neglected. Multi-source-based big data are beneficial to better understand the profile and dynamics of infectious diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07313-6.

The impact of COVID-19 continuous containment and mitigation strategy on the epidemic of vector-borne diseases in China

Background

This study explored the effect of a continuous mitigation and containment strategy for coronavirus disease 2019 (COVID-19) on five vector-borne diseases (VBDs) in China from 2020 to 2021.

Methods

Data on VBDs from 2015 to 2021 were obtained from the National Health Commission of the People’s Republic of China, and the actual trend in disease activity in 2020–2021 was compared with that in 2015–2019 using a two-ratio Z-test and two proportional tests. Similarly, the estimated trend in disease activity was compared with the actual trend in disease activity in 2020.

Results

There were 13,456 and 3684 average yearly cases of VBDs in 2015–2019 and 2020, respectively. This represents a decrease in the average yearly incidence of total VBDs of 72.95% in 2020, from 0.9753 per 100,000 population in 2015–2019 to 0.2638 per 100,000 population in 2020 (t = 75.17, P < 0.001). The observed morbidity rates of the overall VBDs were significantly lower than the predicted rates (47.04% reduction; t = 31.72, P < 0.001). The greatest decline was found in dengue, with a 77.13% reduction (observed rate vs predicted rate: 0.0574 vs. 0.2510 per 100,000; t = 41.42, P < 0.001). Similarly, the average yearly mortality rate of total VBDs decreased by 77.60%, from 0.0064 per 100,000 population in 2015–2019 to 0.0014 per 100,000 population in 2020 (t = 6.58, P < 0.001). A decreasing trend was also seen in the monthly incidence of total VBDs in 2021 compared to 2020 by 43.14% (t = 5.48, P < 0.001).

Conclusions

The results of this study verify that the mobility and mortality rates of VBDs significantly decreased from 2015–2019 to 2020–2021, and that they are possibly associated to the continuous COVID-19 mitigation and contamination strategy implemented in China in 2020–2021.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05187-w.

Epidemiological characteristics of imported respiratory infectious diseases in China, 2014‒2018

Background

With the progress of globalization, international mobility increases, greatly facilitating cross-border transmission of respiratory infectious diseases (RIDs). This study aimed to analyze the epidemiological characteristics and factors influencing imported RIDs, with the goal of providing evidence to support adoption of high-tech, intelligent methods to early find imported RIDs and prevent their spread in China.

Methods

We obtained data of imported RIDs cases from 2014 to 2018 from the Inbound Sentinel Network of Customs and the National Notifiable Diseases Reporting System in China. We analyzed spatial, temporal, and population distribution characteristics of the imported RIDs. We developed an index to describe seasonality. Pearson correlation coefficients were used to examine associations between independent variables and imported cases. Data analyses and visualizations were conducted with R software.

Results

From a total of 1 409 265 253 inbound travelers, 31 732 (2.25/100 000) imported RIDs cases were reported. RIDs cases were imported from 142 countries and five continents. The incidence of imported RIDs was nearly 5 times higher in 2018 (2.81/100 000) than in 2014 (0.58/100 000). Among foreigners, incidence rates were higher among males (5.32/100 000), 0–14-year-olds (15.15/100 000), and cases originating in Oceania (11.10/100 000). The vast majority (90.3%) of imported RIDs were influenza, with seasonality consistent with annual seasonality of influenza. The spatial distribution of imported RIDs was different between Chinese citizens and foreigners. Increases in inbound travel volume and the number of influenza cases in source countries were associated with the number of imported RIDs.

Conclusions

Our study documented importation of RIDs into China from 142 countries. Inbound travel poses a significant risks bringing important RIDs to China. It is urgent to strengthen surveillance at customs of inbound travelers and establish an intelligent surveillance and early warning system to prevent importation of RIDs to China for preventing further spread within China.

Graphical Abstract

Epidemiological characteristics and temporal-spatial analysis of overseas imported dengue fever cases in outbreak provinces of China, 2005–2019

Background

Overseas imported dengue fever is an important factor in local outbreaks of this disease in the mainland of China. To better prevent and control such local outbreaks, the epidemiological characteristics and temporal-spatial distribution of overseas imported dengue fever cases in provincial-level administrative divisions (PLADs) where dengue fever is outbreak in the mainland of China were explored.

Methods

Using the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS), we identified overseas imported dengue fever cases in dengue fever outbreak areas in the mainland of China from 2005 to 2019 to draw the epidemic curve and population characteristic distribution of overseas imported cases in each PLAD. Based on spatial autocorrelation analysis of ArcGIS 10.5 and temporal-spatial scanning analysis of SaTScan 9.5, we analyzed the temporal-spatial distribution of overseas imported dengue fever in dengue fever outbreak areas in the mainland of China.

Results

A total of 11,407 imported cases, mainly from Southeast Asia, were recorded from 2005 to 2019 in these 13 PLADs. Of which 62.1% were imported into Yunnan and Guangdong Provinces. Among the imported cases, there were more males than females, mainly from the 21–50 age group. The hot spots were concentrated in parts of Yunnan, Guangdong and Fujian Provinces. We found the cluster of infected areas were expanding northward.

Conclusions

Based on the analysis of overseas imported dengue cases in 13 PLADs of the mainland of China from 2005 to 2019, we obtained the epidemiological characteristics and spatial distribution of imported dengue cases. Border controls need to pay attention to key population sectors, such as 21–50 years old men and education of key populations on dengue prevention. There is a need to improve the awareness of the prevention and control of imported cases in border areas. At the same time, northern regions cannot relax their vigilance.

Graphical Abstract

The epidemiological characteristics of dengue in high-risk areas of China, 2013-2016

Introduction

Dengue has become a more serious human health concern in China, with increased incidence and expanded outbreak regions. The knowledge of the cross-sectional and longitudinal epidemiological characteristics and the evolutionary dynamics of dengue in high-risk areas of China is limited.

Methods

Records of dengue cases from 2013 to 2016 were obtained from the China Notifiable Disease Surveillance System. Full envelope gene sequences of dengue viruses detected from the high-risk areas of China were collected. Maximum Likelihood tree and haplotype network analyses were conducted to explore the phylogenetic relationship of viruses from high-risk areas of China.

Results

A total of 56,520 cases was reported in China from 2013 to 2016. During this time, Yunnan, Guangdong and Fujian provinces were the high-risk areas. Imported cases occurred almost year-round, and were mainly introduced from Southeast Asia. The first indigenous case usually occurred in June to August, and the last one occurred before December in Yunnan and Fujian provinces but in December in Guangdong Province. Seven genotypes of DENV 1–3 were detected in the high-risk areas, with DENV 1-I the main genotype and DENV 2-Cosmopolitan the secondary one. The Maximum Likelihood trees show that almost all the indigenous viruses separated into different clusters. DENV 1-I viruses were found to be clustered in Guangdong Province, but not in Fujian and Yunnan, from 2013 to 2015. The ancestors of the Guangdong viruses in the cluster in 2013 and 2014 were most closely related to strains from Thailand or Singapore, and the Guangdong virus in 2015 was most closely related to the Guangdong virus of 2014. Based on closest phylogenetic relationships, viruses from Myanmar possibly initiated further indigenous cases in Yunnan, those from Indonesia in Fujian, while viruses from Thailand, Malaysia, Singapore and Indonesia were predominant in Guangdong Province.

Conclusions

Dengue is still an imported disease in China, although some genotypes continued to circulate in successive years. Viral phylogenies based on the envelope gene suggested periodic introductions of dengue strains into China, primarily from Southeast Asia, with occasional sustained, multi-year transmission in some regions of China.

Dengue is the most prevalent and rapidly spreading mosquito-borne viral disease globally. Because of the multiple introductions, dengue outbreaks occurred in epidemic seasons in Southern China, supported by suitable weather conditions. Surveillance data from 2013 to 2016 in China showed that Guangdong, Yunnan and Fujian provinces were the high-risk areas, with dengue outbreaks occurring almost every year. However, knowledge has been lacking of the epidemiological characteristics and the evolution pattern of dengue virus in these high-risk areas. This study shows a variety of epidemiological characteristics and sources of imported cases among the high-risk areas in China, with likely origins primarily from countries in Southeast Asia. Seven genotypes of the DENV 1–3 variety co-circulated with DENV1-I, the main genotype, and DENV 2-Cosmopolitan, the secondary. Genetic relationships among viral strains suggest that the indigenous viruses in the high-risk areas arose from imported viruses and sometimes persisted between years into the next epidemic season, especially in Guangdong Province. Population movement has played a vital role in dengue epidemics in China. This information may be useful in dengue control, especially during epidemic seasons and in the development of an early warning system within the region, in collaboration with bordering countries.

Foodborne Parasites Dominate Current Parasitic Infections in Hunan Province, China

Great progress has been made in the prevention and treatment of human parasitic diseases in China over the past six decades, but parasitic diseases are still one of the most serious public health problems in the world. The specific prevalence of parasitic diseases varies in different provinces due to their geographical environment and the dietary habits of people. In this study, a total of 4,428 patients suspected to have parasitic infection by clinicians or themselves from January 1, 2016, to December 31, 2020 were recommended to our laboratory for further testing. In total, 5,246 samples including fecal, blood, and other body fluids were detected by etiological and immunological methods. Approximately 15.20% (673/4,428) of all suspected patients were infected by at least one species of parasite, and the overall positive rate of suspected patients from Hunan Province was 15.10% (594/3,933). A total of 18 species of parasites, namely, nematodes (4 species), trematodes (5 species), cestodes (4 species), protozoa (2 species), and medical arthropods (3 species), and 3 of them were imported parasites outside of Hunan Province. There are 9 species of foodborne parasites, accounting for 89.92% (464/516) of patients infected by one species of parasite. Common parasites in Hunan Province include plerocercoid, Paragonimus westermani, Clonorchis sinensis, cysticercus, Toxoplasma gondii, and Schistosoma japonicum. In this study, we found that the incidence of soilborne nematode infections has decreased significantly. However, foodborne parasites gradually become the main parasitic infections as well as multiple infections are becoming more common. Therefore, we should not only continue the prevention and control of soil-derived nematodes but also focus on the prevention and control of foodborne parasites in the future.

Global dengue importation: a systematic review

Background

Importation of dengue following globalization presents an emerging threat to global health. However, evidence on global geographical sources and the potential of dengue importation globally are lacking. This study aims to systematically review the sources of dengue importation globally and the risk of dengue outbreaks globally.

Methods

This systematic review was conducted in accordance to Cochrane’s PRISMA guidelines. Articles published through 31 December 2019 with laboratory-confirmed dengue imported cases were consolidated from PubMed, EMBASE and Scopus. Sources of dengue importation reported worldwide were analysed by country and geographical regions. Sources of dengue importation into United States of America and Europe specifically were also analysed.

Results

A total of 3762 articles were found. Among which, 210 articles—documenting 14,972 imported dengue cases with reported sources—were eligible. 76.3% of imported cases worldwide were from Asia. 15.7%, 5.6%, 2.0% and 0.1% were imported from the Americas, Africa, Oceania and Europe regions respectively. Imported dengue cases in the U.S. were from Americas (55.3%), Asia (34.7%), Africa (6.7%) and Oceania (3.3%). Imported dengue cases in Europe were from Asia (66.0%), Americas (21.9%), Africa (10.8%) and Oceania (1.1%).

Conclusion

The potential of dengue outbreaks occurring globally, especially among non-endemic regions with dengue-susceptible populations is high. With the expansion of Aedes mosquito population globally due to global warming and globalisation, dengue importation constitutes an emerging global health security threat.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06740-1.

Dengue Virus Type 1 Infection in Traveler Returning from Benin to France, 2019

We investigated a case of dengue virus type 1 infection acquired in Benin. Phylogenetic analysis revealed the strain belongs to genotype V but clusters with Asian, rather than with known African, strains. Our finding suggests the introduction of Asian dengue virus in West Africa.

Travel-related infection in Guangzhou, China,2009-2019

BACKGROUND

We analyzed the epidemiological characteristics of travel-related infectious diseases in reported Guangzhou between 2009 and 2019 to provide a scientific basis for prevention and control strategies.

METHOD

The infectious diseases report information system of China was mined for case reports, combined with clinical diagnosis records, and analyzed.

RESULTS

Between 2009 and 2019, 1478 cases of imported infectious diseases were reported in Guangzhou. Dengue fever accounted for 46.14%of cases and malaria accounted for 45.47% of cases. The patients with imported travel-related infection cases were mainly male (75.88%), Chinese (75.57%), and aged 20-45 years (83.01%). Cases increased from May each year, peaked between August and September, and declined rapidly after October. The main source areas of import were Africa and other countries in Asia.

CONCLUSIONS

Dengue fever and malaria are the main travel-related infection in Guangzhou, and are generally brought in by male Chinese workers. Intervention and health education in this population should be strengthened to prevent and control travel-related infection.

Nurses' core emergency competencies for COVID-19 in China: A cross-sectional study

Aim

To investigate nurses’ core emergency competencies for handling the coronavirus disease‐19 (COVID‐19) and analyse the factors associated with those competencies.

Background

COVID‐19 has become a major global public health event. Nursing staff have played an important role in COVID‐19 prevention and control. Understanding their emergency competencies for handling COVID‐19, and the potential disadvantages will help governments to develop targeted training policies and improve nurses’ capacities in relation to pandemics and emergency preparedness.

Introduction

COVID‐19 is a disastrous infectious disease, but the competencies of nurses in China to handle COVID‐19 have not been well documented.

Methods

We conducted a cross‐sectional survey on nurses from 22 provinces of China in February 2020. The scores of self‐report questionnaires were used to analyse their competencies for core emergency care, and linear regression analysis was used to explore influential factors.

Results

A total of 2570 nurses participated. The study revealed that nurses had a good grasp of COVID‐19 knowledge, but the majority of nurses lacked experience in isolation ward work and emergency training. We found that age, professional title, work department, major work content, total work time, disaster rescue history, emergency training and infectious disease training were associated with core emergency competencies.

Conclusions

Chinese nurses were qualified for handling COVID‐19 but still need to strengthen the accumulation of practical experience.

Implications for nursing

Nurses should actively participate in emergencies to strengthen their operational capacity, whether in training or actual practice.

Implications for nursing/health policy

Managers should improve relevant policies to ensure that nurses have more opportunities to participate in the practical training of health emergencies and explore effective training methods to improve the ability of nurses to respond to these.

How Do Economic Fluctuations Affect the Mortality of Infectious Diseases?

This paper uses the mixed frequency vector autoregression model to explore the impact of economic fluctuations on infectious diseases mortality (IDM) from China perspective. We find that quarterly gross domestic product (GDP) fluctuations have a negative impact on the annual IDM, indicating that the mortality of infectious diseases varies counter-cyclically with the business cycle in China. Specifically, IDM usually increases with deterioration in economic conditions, and vice versa. The empirical results are consistent with the hypothesis I derived from the theoretical analysis, which highlights that economic fluctuations can negatively affect the mortality of infectious diseases. The findings can offer revelations for the government to consider the role of economic conditions in controlling the epidemic of infectious diseases. Policymakers should adopt appropriate and effective strategies to mitigate the potential negative effects of macroeconomic downturns on the mortality of infectious diseases. In the context of the COVID-19 pandemic, these analyses further emphasize the importance of promoting economic growth, increasing public health expenditure, and preventing and controlling foreign infectious diseases.

The Origin and Molecular Epidemiology of Dengue Fever in Hainan Province, China, 2019

There was an outbreak of Dengue fever on September 5, 2019, in Hainan Province, which has not been endemic for 28 years. We aim to describe the clinical and epidemiological features of the 2019 outbreak in Hainan Province and identify the cause. All type 1 Dengue fever cases that occurred in this outbreak of Hainan exhibited mild clinical symptoms. The epidemiological investigations indicate that the outbreak might originate from workers in the Xiuying area, Haikou City, form a concentrated outbreak, and then spread out. Bayesian phylogenies results and epidemiological data were used to infer a likely series of events for the dengue virus's potential spread and trace the possible sources. The strains' sequences were close to a sequence from the nearby Guangdong province, supporting the hypothesis that the dengue virus was imported from Guangdong province and then spread across Hainan province. Furthermore, it is interesting that two other strains didn't group with this cluster, suggesting that additional introduction pathways might exist. The study indicated that the dengue fever epidemic presented two important modes in Hainan. Firstly, epidemics prevalence was caused by imported cases, and then endogenous epidemics broke out in the natural epidemic focus.

Epidemiology of imported infectious diseases, China, 2014-18

BACKGROUND

The frequent movement of population between countries brings an increasing number of travel-related infections. This study aims to define the spectrum and dynamics of imported infections observed from international travel in the Chinese mainland.

METHODS

Sick travellers were screened by inbound sentinel surveillance and post-travel clinic visits from 2014 to 18. The infections were classified as respiratory, gastrointestinal, vector-borne, blood/sexually transmitted and mucocutaneous. The analysed variables included the place of origin of the travellers (Chinese or foreign) and the time when travel-related infection was present (at the time of return, during travel and post-travel visits to the clinic).

RESULTS

In total, 58 677 cases were identified amongst 1 409 265 253 travellers, with an incidence of 41.64/million, comprising during-travel incidence of 27.44/million and a post-travel incidence of 14.20/million. Respiratory infections constituted the highest proportion of illnesses during travel (81.19%, 31 393 of 38 667), which mainly came from Asian countries and tourists; with influenza virus and rhinovirus infections being mainly diagnosed. Vector-borne diseases constituted the highest proportion of post-travel illnesses (98.14%, 19 638 of 20 010), which were mainly diagnosed from African countries and labourers; with malaria and dengue fever being mainly diagnosed. The differential infection spectrum varied in terms of the traveller's demography, travel destination and travel purpose. As such, a higher proportion of foreign travellers had blood/sexually transmitted diseases (89.85%, 2832 of 3152), while Chinese citizens had a higher prevalence of vector-borne diseases (85.98%, 19 247 of 22 387) and gastrointestinal diseases (79.36%, 1115 of 1405). The highest incidence rate was observed amongst travellers arriving from Africa, while the lowest was observed amongst travellers arriving from Europe.

CONCLUSIONS

The findings might help in preparing recommendations for travellers and also aid in primary care or other clinics that prepare travellers before trips abroad. The findings will also help to identify locations and the associated types of infections that might require attention.

Effects of natural and socioeconomic factors on dengue transmission in two cities of China from 2006 to 2017

Dengue fever (DF) is a common and rapidly spreading vector-borne viral disease in tropical and subtropical regions. In recent years, in China, DF still poses an increasing threat to public health in many cities; but the incidence shows significant spatiotemporal differences. The purpose of this study was to identify the key factors affecting the spatial and temporal distribution of DF. We collected natural environmental and socio-economic data for two adjacent cities, Guangzhou (73 variables) and Foshan (71 variables), with the most DF cases in China. We performed random forest modelling to rank the factors according to their level of importance, and used negative binomial regression analysis to compare the risk factors between outbreak years and non-outbreak years. The natural environmental factors contributing to DF incidence for Guangzhou were temperature (relative risk (RR) = 18.80, 95% confidence interval (CI) = 3.11-113.67), humidity (RR = 1.85, 95% CI = 1.17-2.90) and green area (RR = 12.11, 95% CI = 6.14-55.50), and for Foshan was forest coverage (RR = 5.83, 95% CI = 2.72-12.45). Socio-economic impact were shown in Guangzhou with foreign visitor (RR = 1.18, 95% CI = 1.05-1.34) and oversea air passenger transport (RR = 7.34, 95% CI = 2.26-23.86); in Foshan, with oversea tourism (RR = 1.65, 95% CI = 1.34-2.04); and in Guangzhou-Foshan, with the development of intercity metro (RR = 1.26, 95% CI = 1.10-1.44). The difference between the two cities was the greater impact of the foreign visitor, green spaces and climate factor on DF in Guangzhou; the impact of the construction of intercity metro; and the more significant impact of oversea tourism on DF in Foshan. Our results suggest meaningful clues to public health authorities implementing joint interventions on DF prevention and early warning, to increase health education on DF prevention for international visitors and oversea travelers, and cross-city metro passengers; using rapid body temperature detection in public places such as airports, metros and parks can help detect cases early.

Epidemiological Characteristics of Notifiable Infectious Diseases among Foreign Cases in China, 2004-2017

OBJECTIVE

We aimed to assess the features of notifiable infectious diseases found commonly in foreign nationals in China between 2004 and 2017 to improve public health policy and responses for infectious diseases.

METHODS

We performed a descriptive study of notifiable infectious diseases among foreigners reported from 2004 to 2017 in China using data from the Chinese National Notifiable Infectious Disease Reporting System (NNIDRIS). Demographic, temporal-spatial distribution were described and analyzed.

RESULTS

A total of 67,939 cases of 33 different infectious diseases were reported among foreigners. These diseases were seen in 31 provinces of China and originated from 146 countries of the world. The infectious diseases with the highest incidence number were human immunodeficiency virus (HIV) of 18,713 cases, hepatitis B (6,461 cases), hand, foot, and mouth disease (6,327 cases). Yunnan province had the highest number of notifiable infectious diseases in foreigners. There were different trends of the major infectious diseases among foreign cases seen in China and varied among provinces.

CONCLUSIONS

This is the first description of the epidemiological characteristic of notifiable infectious diseases among foreigners in China from 2004 to 2017. These data can be used to better inform policymakers about national health priorities for future research and control strategies.

Imported dengue serotype 1 outbreak in a non-endemic region, China, 2017: A molecular and seroepidemiological study

OBJECTIVES

Beginning in June 2017, numerous dengue virus (DENV) infections occurred in the Jining City of Shandong Province, formerly a dengue-free region in East China. We sought to describe the clinical and epidemiological features of this outbreak.

METHODS

We reviewed the clinical records and epidemiological data regarding a case series of patients diagnosed with DENV in Jining City, from June 30 to September 14, 2017. Diagnosis was confirmed by molecular method, culture, or rapid diagnostic tests. Sequencing of the DENV envelope gene or the whole viral genome was performed for 11 patients. Additionally, neutralizing antibodies against DENV was measured among patients and residents from their same villages.

RESULTS

Data from 150 patients were evaluated in this outbreak. None were diagnosed with dengue hemorrhagic fever or dengue shock syndrome. The patients' ages ranged between 2-88 years (median 51 years, [IQR=37.5-64.3]), and 100 (66.7%) were female. Epidemiological analyses implicated a man who had visited Saudi Arabia as the likely source of the outbreak. Phylogenetic studies identified DENV serotype 1. Most of the patients demonstrated increases of neutralizing antibody titers one year after infection compared with titers three months after infection. The residents living in dengue-affected villages had a significant higher seroprevalence of 21.2% (95%CI 16.9-25.5) than residents (3.2%, 95%CI-0.36-6.7) living in a non-dengue-affected village.

CONCLUSIONS

This report documents the first dengue outbreak in Shandong Province, China, in more than 60 years. It underscores the need for medical providers to record patients' travel histories and to consider dengue in their differential diagnoses.

The effects of border control and quarantine measures on the spread of COVID-19

The rapid expansion of coronavirus disease 2019 (COVID-19) has been observed in many parts of the world. Many newly reported cases of COVID-19 during early outbreak phases have been associated with travel history from an epidemic region (identified as imported cases). For those cases without travel history, the risk of wider spreads through community contact is even higher. However, most population models assume a homogeneous infected population without considering that the imported and secondary cases contracted by the imported cases can pose different risks to community spread. We have developed an "easy-to-use" mathematical framework extending from a meta-population model embedding city-to-city connections to stratify the dynamics of transmission waves caused by imported, secondary, and others from an outbreak source region when control measures are considered. Using the cumulative number of the secondary cases, we are able to determine the probability of community spread. Using the top 10 visiting cities from Wuhan in China as an example, we first demonstrated that the arrival time and the dynamics of the outbreaks at these cities can be successfully predicted under the reproduction number R₀ = 2.92 and incubation period τ = 5.2 days. Next, we showed that although control measures can gain extra 32.5 and 44.0 days in arrival time through an intensive border control measure and a shorter time to quarantine under a low R₀ (1.4), if the R₀ is higher (2.92), only 10 extra days can be gained for each of the same measures. This suggests the importance of lowering the incidence at source regions together with infectious disease control measures in susceptible regions. The study allows us to assess the effects of border control and quarantine measures on the emergence and global spread of COVID-19 in a fully connected world using the dynamics of the secondary cases.

Increase in cases of dengue in China, 2004-2016: A retrospective observational study

BACKGROUND

Dengue fever (DF) is a vector-bore infectious disease that can infect humans, and has been recognized as a global public health threat, with significant morbidity and mortality rates.

METHOD

To describe the epidemiological profile of DF in China during 2004-2016, the morbidity data of DF by age-group, season (different months) and geographic location (different provinces) were obtained from the public health science data center of China for subsequent epidemiological analysis.

RESULTS

The results showed that the incidence of DF shows striking annual variations, and two large outbreaks occurred in 2006-2007 and during 2012-2015. The results of the average morbidity rates (cases/100,000 population) for human DF indicated that among all dengue fever cases, Guangdong in southern area of China had the highest rates (3.8160 cases/100,000 population), followed by Yunnan (0.6614 cases/100,000 population), Fujian (0.3463 cases/100,000 population) and Guangxi (0.1474 cases/100,000 population). Epidemic peaks occurred in late June and early November, and the incidence rate among middle-aged people (30-45 years old) was relatively high, followed by rates among 15-29 and 45-59 age groups.

CONCLUSION

In this study, we demonstrated the epidemiological profile of DF circulating in China and revealed the geographic distribution, dynamic transmission, seasonal asymmetries and age distribution, which will provide guidelines on the prevention and control of DF in China. The present investigation is useful in the risk assessment of DF transmission, to predict DF outbreaks and the prevention and control strategies should be used along with surveillance to reduce the spread of DF in China.

Toward the Elimination of Malaria in China: A Retrospective Analysis of Malaria-Endemic Characteristics and Prevention Effects in Yantai, Shandong Province, 1951 to 2017

Objectives: To study the epidemiological characteristics of malaria and the effects of comprehensive malaria control implementation in Yantai, as well as to provide a scientific basis for future malaria elimination. Materials and Methods: A retrospective analysis was conducted to explore the epidemiological changes and prevention effects in Yantai from 1951 to 2017. The malaria data before 2004 were collected from paper-based annual reports, and data after 2004 came from the Infectious Diseases Information Reporting Management System. Results: A total of 81,286 malaria cases were identified in Yantai from 1957 to 2017, with two peaks occurring in 1966 (120.93/100,000) and 1970-1972 (366.12/100,000). From 1951 to 2003, the case classification was mainly Plasmodium vivax (99.80%); the first case attributed to Plasmodium falciparum occurred in 2004, and P. falciparum became the main cause of malaria after 2011. All cases reported since 2010 have been imported cases, and the last indigenous case was caused by P. vivax in 2008. A total of 129 imported cases were reported from 2010 to 2017, most of which originated in Africa (93.80%), mainly in men aged 30-49 years (68.28%). From 1951 to 1973, 73,868 cases of malaria were diagnosed with clinical symptoms, and from 1974 to 2017, 818,943 cases in fever patients were diagnosed with blood tests. Conclusions: To achieve the goal of eliminating malaria by 2020, Yantai should continue to strengthen the management of migrant population, including improving malaria surveillance for returnees and immigrants from overseas endemic areas, and continue to increase the training of medical personnel to improve their diagnostic ability.

Management of imported malaria cases and healthcare institutions in central China, 2012-2017: application of decision tree analysis

Background

Imported malaria has been an important challenge for China. Fatality rates from malaria increased in China, particularly in Henan Province, primarily due to malpractice and misdiagnoses in healthcare institutions, and the level of imported malaria. This study aims to investigate the relationship between the state of diagnosis and subsequent complications among imported malaria cases at healthcare institutions, based on malaria surveillance data in Henan Province from 2012 to 2017.

Methods

A retrospective descriptive analysis was performed using data from the Centre for Disease Control and Prevention, Zhengzhou City, the capital of Henan Province. A decision tree method was exploited to provide valuable insight into the correlation between imported malaria cases and healthcare institutions.

Results

From 2012 to 2017, there were 371 imported malaria cases, mostly in males aged between 20 and 50 years, including 319 Plasmodium falciparum cases. First visits of 32.3%, 19.9% and 15.9% malaria cases for treatment were to provincial, municipal and county healthcare institutions, respectively. The time interval between onset and initial diagnosis of 284 cases (76.5%) and the time interval between initial diagnosis and final diagnosis of 197 cases (53.1%) was no more than 72 h. An apparent trend was found that there were notably fewer patients misdiagnosed at first visit to healthcare institutions of a higher administrative level; 12.5% of cases were misdiagnosed in provincial healthcare institutions compared to 98.2% in private clinics, leading to fewer complications at healthcare institutions of higher administrative level due to correct initial diagnosis. In the tree model, the rank of healthcare facilities for initial diagnosis, and number of days between onset and initial diagnosis, made a major contribution to the classification of initial diagnosis, which subsequently became the most significant factor influencing complications developed in the second tree model. The classification accuracy were 82.2 and 74.1%, respectively for the tree models of initial diagnosis and complications developed.

Conclusion

Inadequate seeking medical care by imported malaria patients, and insufficient capacity to diagnose malaria by healthcare institutions of lower administrative level were identified as major factors influencing complications of imported malaria cases in Henan Province. The lack of connection between uncommon imported malaria cases and superior medical resources was found to be the crucial challenge. A web-based system combined with WeChat to target imported malaria cases was proposed to cope with the challenge.