Dynamics analysis of strangles with asymptomatic infected horses and long-term subclinical carriers.

Strangles is one of the most prevalent horse diseases globally. The infected horses may be asymptomatic and can still carry the infectious pathogen after it recovers, which are named asymptomatic infected horses and long-term subclinical carriers, respectively. Based on these horses, this paper establishes a dynamical model to screen, measure, and model the spread of strangles. The basic reproduction number $ \mathcal{R}_0 $ is computed through a next generation matrix method. By constructing Lyapunov functions, we concluded that the disease-free equilibrium is globally asymptotically stable if $ \mathcal{R}_0 < 1 $, and the endemic equilibrium exits uniquely and is globally asymptotically stable if $ \mathcal{R}_0 > 1 $. For example, while studying a strangles outbreak of a horse farm in England in 2012, we computed an $ \mathcal{R}_0 = 0.8416 $ of this outbreak by data fitting. We further conducted a parameter sensitivity analysis of $ \mathcal{R}_0 $ and the final size by numerical simulations. The results show that the asymptomatic horses mainly influence the final size of this outbreak and that long-term carriers are connected to an increased recurrence of strangles. Moreover, in terms of the three control measures implemented to control strangles(i.e., vaccination, implementing screening regularly and isolating symptomatic horses), the result shows that screening is the most effective measurement, followed by vaccination and isolation, which can provide effective guidance for horse management.

Incidence and trends of 17 notifiable bacterial infectious diseases in China, 2004-2019.

BACKGROUND: Certain bacterial infectious diseases are categorized as notifiable infectious diseases in China. Understanding the time-varying epidemiology of bacterial infections diseases can provide scientific evidence to inform prevention and control measures. METHODS: Yearly incidence data for all 17 major notifiable bacterial infectious diseases (BIDs) at the province level were obtained from the National Notifiable Infectious Disease Reporting Information System in China between 2004 and 2019. Of them 16 BIDs are divided into four categories, respiratory transmitted diseases (RTDs, 6 diseases), direct contact/fecal-oral transmitted diseases (DCFTDs, 3 diseases), blood-borne/sexually transmitted diseases (BSTDs, 2 diseases), and zoonotic and vector-borne diseases (ZVDs, 5 diseases), and neonatal tetanus is excluded in the analysis. We characterized the demographic, temporal, and geographical features of the BIDs and examined their changing trends using a joinpoint regression analysis. RESULTS: During 2004‒2019, 28 779 thousand cases of BIDs were reported, with an annualized incidence rate of 134.00 per 100 000. RTDs were the most commonly reported BIDs, accounting for 57.02% of the cases (16 410 639/28 779 000). Average annual percent changes (AAPC) in incidence were - 1.98% for RTDs, - 11.66% for DCFTDs, 4.74% for BSTDs, and 4.46% for ZVDs. Females had a higher incidence of syphilis than males, and other BIDs were more commonly reported in males. Among 0-5-year-olds, the diseases with the largest increases in incidence were pertussis (15.17% AAPC) and scarlet fever (12.05%). Children and students had the highest incidence rates of scarlet fever, pertussis, meningococcal meningitis, and bacillary dysentery. Northwest China had the highest incidence of RTDs, while South and East China had the highest incidences of BSTDs. Laboratory confirmation of BIDs increased from 43.80 to 64.04% during the study period. CONCLUSIONS: RTDs and DCFTDs decreased from 2004 to 2019 in China, while BSTDs and ZVDs increased during the same period. Great attention should be paid to BSTDs and ZVDs, active surveillance should be strengthened, and timely control measures should be adopted to reduce the incidence.

Etiological and epidemiological features of acute meningitis or encephalitis in China: a nationwide active surveillance study.

BACKGROUND: Acute meningitis or encephalitis (AME) results from a neurological infection causing high case fatality and severe sequelae. AME lacked comprehensive surveillance in China. METHODS: Nation-wide surveillance of all-age patients with AME syndromes was conducted in 144 sentinel hospitals of 29 provinces in China. Eleven AME-causative viral and bacterial pathogens were tested with multiple diagnostic methods. FINDINGS: Between 2009 and 2018, 20,454 AME patients were recruited for tests. Based on 9,079 patients with all-four-virus tested, 28.43% (95% CI: 27.50%‒29.36%) of them had at least one virus-positive detection. Enterovirus was the most frequently determined virus in children <18 years, herpes simplex virus and Japanese encephalitis virus were the most frequently determined in 18-59 and ≥60 years age groups, respectively. Based on 6,802 patients with all-seven-bacteria tested, 4.43% (95% CI: 3.94%‒4.91%) had at least one bacteria-positive detection, Streptococcus pneumoniae and Neisseria meningitidis were the leading bacterium in children aged <5 years and 5-17 years, respectively. Staphylococcus aureus was the most frequently detected in adults aged 18-59 and ≥60 years. The pathogen spectrum also differed statistically significantly between northern and southern China. Joinpoint analysis revealed age-specific positive rates, with enterovirus, herpes simplex virus and mumps virus peaking at 3-6 years old, while Japanese encephalitis virus peaked in the ≥60 years old. As age increased, the positive rate for Streptococcus pneumoniae and Escherichia coli statistically significantly decreased, while for Staphylococcus aureus and Streptococcus suis it increased. INTERPRETATION: The current findings allow enhanced identification of the predominant AME-related pathogen candidates for diagnosis in clinical practice and more targeted application of prevention and control measures in China, and a possible reassessment of vaccination strategy. FUNDING: China Mega-Project on Infectious Disease Prevention and the National Natural Science Funds.

Serological Prevalence Survey Among the High-Risk Populations of Brucellosis-Endemic Areas - China, 2019-2020.

What is already known about this topic? Timely screening of high-risk population is important to improve the early detection of brucellosis among the endemic areas during the high incidence seasons, which is also required by the National Brucellosis Prevention and Control Plan (2016-2020) (NBPCP). What is added by this report? Seroepidemiological characteristics of brucellosis in high-risk populations were obtained and special occupational populations were found. The seroprevalence of brucellosis has been decreasing compared with that reported in the recent years due to the ongoing implementation of control measures in endemic areas. What are the implications for public health practice? Special occupational populations could be promptly detected using routine screening, which makes it possible to initiate standardized treatment for infected patients as early as possible. It also reminds us to pay attention to special occupational populations to improve their knowledge of brucellosis and reduce the risk of infection.

Brucellosis Knowledge and Personal Protective Equipment Usage Among High-Risk Populations in Brucellosis-Endemic Areas - China, 2019-2020.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: According to the National Brucellosis Prevention and Control Plan (2016-2020) (NBPCP), the awareness rate of high-risk populations in brucellosis-endemic areas should reach 90% by 2020. But the updated results have not been reported. WHAT IS ADDED BY THIS REPORT?: This report determined the awareness rate of brucellosis (17.74%), utilization of personal protective equipment (PPE) (20.13%), and their relationship with seroprevalence, which provides evidence for the effectiveness of the implementation of NBPCP. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: The results suggest that health education should be conducted for high-risk populations to improve their brucellosis and protection knowledge.

Characteristics of diarrheagenic Escherichia coli among patients with acute diarrhea in China, 2009‒2018.

Objectives To investigate the epidemiological features of diarrheagenic Escherichia coli (DEC) in patients with acute diarrhea in China. Methods An active sentinel surveillance was performed in all-age patients with acute diarrhea in China, 2009‒2018. DEC was isolated and identified by serological assay and PCR from stool samples. Results DEC was determined in 6.68% (6,119/91,651) of the patients, with higher positive rates among females than among males (6.97% vs. 6.46%) and among 18‒59 years patients (7.88%) than among other age groups. Five pathotypes were identified, the most prevalent was enteroaggregative E. coli (EAEC), followed by enteropathogenic E. coli (EPEC), and enterotoxigenic E. coli (ETEC). Pediatric patients <5 years had higher positive rate of EAEC (2.07%), followed by EPEC (1.81%), and enterohemorrhagic E. coli (EHEC) (0.31%), while the 18‒59 years patients had higher infection of ETEC (2.36%). ETEC and EPEC were more frequently identified in urban than rural areas, with age and gender adjusted positive rate of 1.68% vs. 1.14% respectively, and 1.77% vs. 1.55%, while EIEC and EHEC were more frequently identified in rural areas. Conclusions These findings highlight the epidemiology features of DEC and underscores the need for conducting DEC surveillance.

Etiological and epidemiological features of acute respiratory infections in China.

Nationwide prospective surveillance of all-age patients with acute respiratory infections was conducted in China between 2009‒2019. Here we report the etiological and epidemiological features of the 231,107 eligible patients enrolled in this analysis. Children <5 years old and school-age children have the highest viral positivity rate (46.9%) and bacterial positivity rate (30.9%). Influenza virus, respiratory syncytial virus and human rhinovirus are the three leading viral pathogens with proportions of 28.5%, 16.8% and 16.7%, and Streptococcus pneumoniae, Mycoplasma pneumoniae and Klebsiella pneumoniae are the three leading bacterial pathogens (29.9%, 18.6% and 15.8%). Negative interactions between viruses and positive interactions between viral and bacterial pathogens are common. A Join-Point analysis reveals the age-specific positivity rate and how this varied for individual pathogens. These data indicate that differential priorities for diagnosis, prevention and control should be highlighted in terms of acute respiratory tract infection patients' demography, geographic locations and season of illness in China.

Etiological, epidemiological, and clinical features of acute diarrhea in China.

National-based prospective surveillance of all-age patients with acute diarrhea was conducted in China between 2009‒2018. Here we report the etiological, epidemiological, and clinical features of the 152,792 eligible patients enrolled in this analysis. Rotavirus A and norovirus are the two leading viral pathogens detected in the patients, followed by adenovirus and astrovirus. Diarrheagenic Escherichia coli and nontyphoidal Salmonella are the two leading bacterial pathogens, followed by Shigella and Vibrio parahaemolyticus. Patients aged <5 years had higher overall positive rate of viral pathogens, while bacterial pathogens were more common in patients aged 18‒45 years. A joinpoint analysis revealed the age-specific positivity rate and how this varied for individual pathogens. Our findings fill crucial gaps of how the distributions of enteropathogens change across China in patients with diarrhea. This allows enhanced identification of the predominant diarrheal pathogen candidates for diagnosis in clinical practice and more targeted application of prevention and control measures.

Morbidity Analysis of the Notifiable Infectious Diseases in China, 2018.

What is already known about this topic? Annual morbidity analysis reports that summarized trends and changing epidemiology for notifiable diseases were published in 2013 and 2015 (1,2). What is added by this report? In 2018, the morbidity of national notifiable diseases was 559.41 per 100,000 population, an increase of 12.88% compared with the average rate between 2015-2017. The five notifiable diseases with the highest reported morbidity were hand, foot, and mouth disease (HFMD), infectious diarrhea, hepatitis B, tuberculosis, and influenza. The five regions with the highest reported morbidity of infectious diseases were Zhejiang Province, Guangxi Autonomous Region, Guangdong Province, Beijing Municipality, and Xinjiang Autonomous Region. What are the implications for public health practice? Evidence on notifiable disease morbidity trends and changing epidemiology should help disease control and prevention agencies and medical institutions direct their response and prevention efforts. In addition, this report demonstrates the continued need for surveillance systems and high-quality data to identify focal points for disease control.