Role of Aedes aegypti and Aedes albopictus during the 2011 dengue fever epidemics in Hanoi, Vietnam

Objective: To record the human cases of dengue fever(DF) and investigate the Aedes mosquito species circulating during the Hanoi 2011 DF epidemics. Methods: 24 different outbreak points were recorded in 8 districts between August and December 2011. Results: 140 patients were hospitalized following dengue diagnostic with a predominance of males(59.3%) and the 15-34 age class. Only DENV-1(11.27%) and DENV-2(88.73%) serotypes were detected in human samples. Mosquito sampling performed in and around patients households revealed the predominance of Aedes aegypti(95.15%) versus Aedes albopictus(4.85%). There is a positive correlation between the population density of Aedes aegypti and the number of human cases and duration of outbreaks. Conclusions: This was not observed for Aedes albopictus. 3 pools of Aedes aegypti were positive with dengue virus, two with DENV-1 and one with DENV-2.

HLA-G 3’UTR 14 bp Insertion Is Associated with a Decreased Risk of Developing Human African Trypanosomiasis in the Côte d’Ivoire Population

Human African trypanosomiasis (HAT), or sleeping sickness, caused by Trypanosoma brucei gambiense, is associated with diverse clinical outcomes. Host’s genetic factors involved in immunity are potential factors that can regulate infection. Genetic polymorphisms within HLA-G could influence the level of HLA-G expression and therefore play a critical role in infection outcomes. The goal of our study was to investigate the association of 14 bp Indel HLA-G polymorphism with the susceptibility/resistance to HAT. DNA samples were collected from 119 cases, 221 controls and 43 seropositive individuals living in Ivorian HAT foci. The 14 bp Indel polymorphism was determined by PCR. Homozygous individuals for 14 bp insertion had a lower risk of progressing to active HAT (p = 0.012, OR = 0.27, 95% CI: 0.09 - 0.8). Moreover, the frequency of 14 bp insertion homozygous genotype was higher in the seropositive group (11%) than in the HAT cases group (3%) (p = 0.043, OR = 0.27, 95% CI: 0.07 - 0.99), which suggested a protective effect of 14 bp insertion homozygous genotype. Genetic polymorphisms in HLA-G may be associated with a variable risk to develop HAT. The 14 bp insertion appears to favour the occurrence of long-lasting T. b. gambiense latent infections.

Tuberculosis Prevalence Trends from a Predictive Modelling Study-10 High-Burden Countries,1980-2035

What is already known about this topic?Given the challenges presented by drug-resistant strains of tuberculosis(TB)and the rising mobility of the population,achieving the objective of eradicating TB appears uncertain.What is added by this report?The examination of TB incidence trends in 10 highburden countries(HBCs)indicated a steady rise in cases,with India and China jointly accounting for nearly 70%of the burden.Projections for the future show diverse trajectories in these countries,with potential difficulties in reaching the TB elimination target,especially in Nigeria,Congo,and South Africa.What are the implications for public health practice?The number of TB cases is on the rise.It is crucial to learn from successful strategies to improve TB prevention and control worldwide through collaborative efforts.

Investigation on the Management for Patients with Echinococcosis Treated with Albendazole-Three PLADs,China,2019

Summary What is already known about this topic?In China,patients with echinococcosis receive complimentary healthcare services,such as medical treatment,diagnostic examinations,and follow-up care.Despite this,no studies have been conducted to assess the quality of patient management to date.What is added by this report?This study reviewed the medical records of 899 patients who underwent albendazole treatment across 10 endemic counties.Out of 634 evaluable patient files,the proportion of patients with a ratio of actual followup and reexamination times to theoretical follow-up and reexamination times≥0.8 were both low(21.92%and 23.19%,respectively).What are the implications for public health practices?This study identified weaknesses and specific issues in patient management and proposed feasible recommendations to enhance patient file documentation,follow-up,and reexamination.

Feasibility of Booster Vaccination in High-Risk Populations for Controlling Coronavirus Variants—China,2021

Introduction:Vaccination booster shots are completely necessary for controlling breakthrough infections of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)in China.The study aims to estimate effectiveness of booster vaccines for high-risk populations(HRPs).Methods:A vaccinated Susceptible-Exposed-Symptomatic-Asymptomatic-Recovered/Removed(SEIAR)model was developed to simulate scenarios of effective reproduction number(Reff)from 4 to 6.Total number of infectious and asymptomatic cases were used to evaluated vaccination effectiveness.Results:Our model showed that we could not prevent outbreaks when covering 80%of HRPs with booster unless Reff=4.0 or the booster vaccine had efficacy against infectivity and susceptibility of more than 90%.The results were consistent when the outcome index was confirmed cases or asymptomatic cases.Conclusions:An ideal coronavirus disease 2019(COVID-19)booster vaccination strategy for HRPs would be expected to reach the initial goal to control the transmission of the Delta variant in China.Accordingly,the recommendation for the COVID-19 booster vaccine should be implemented in HRPs who are already vaccinated and could prevent transmission to other groups.

Transmissibility of tuberculosis among students and non-students:an occupational-specific mathematical modelling

Background: Recently, despite the steady decline in the tuberculosis (TB) epidemic globally, school TB outbreaks have been frequently reported in China. This study aimed to quantify the transmissibility ofMycobacterium tuberculosis (MTB) among students and non-students using a mathematical model to determine characteristics of TB transmission.Methods: We constructed a dataset of reported TB cases from four regions (Jilin Province, Xiamen City, Chuxiong Prefecture, and Wuhan City) in China from 2005 to 2019. We classified the population and the reported cases under student and non-student groups, and developed two mathematical models [nonseasonal model (Model A) and seasonal model (Model B)] based on the natural history and transmission features of TB. The effective reproduction number (R(eff)) of TB between groups were calculated using the collected data.Results: During the study period, data on 456,423 TB cases were collected from four regions: students accounted for 6.1% of cases. The goodness-of-fit analysis showed that Model A had a better fitting effect (P < 0.001). The average R_(eff) of TB estimated from Model A was 1.68 [interquartile range (IQR): 1.20–1.96] in Chuxiong Prefecture, 1.67 (IQR: 1.40–1.93) in Xiamen City, 1.75 (IQR: 1.37–2.02) in Jilin Province, and 1.79 (IQR: 1.56–2.02) in Wuhan City. The average R_(eff) of TB in the non-student population was 23.30 times (1.65/0.07) higher than that in the student population.Conclusions: The transmissibility of MTB remains high in the non-student population of the areas studied, which is still dominant in the spread of TB. TB transmissibility from the non-student-to-student-population had a strong influence on students. Specific interventions, such as TB screening, should be applied rigorously to control and to prevent TB transmission among students.

The maximum likelihood identification method applied to insect morphometric data

To distinguish species or populations using morphometric data is generally processed through multivariate analyses, in particular the discriminant analysis. We explored another approach based on the maximum likelihood method. Simple statistics based on the assumption of normal distribution at a single variable allows to compute the chance of observing a particular data （or sample） in a given reference group. When data are described by more than one variable, the maximum likelihood （MLi） approach allows to combine these chances to find the best fit for the data. Such approach assumes independence between variables. The assumptions of normal distribution of variables and independence between them are frequently not met in morphometrics, but improvements may be obtained after some mathematical transformations. Provided there is strict anatomical correspondence of variables between unknown and reference data, the MLi classification produces consistent classification. We explored this approach using various input data, and compared validated classification scores with the ones obtained after the Mahalanobis distance-based classification. The simplicity of the method, its fast computation, performance and versatility, make it an interesting complement to other classification techniques.

The optimal vaccination strategy to control COVID-19:a modeling study in Wuhan City,China

Background: Reaching optimal vaccination rates is an essential public health strategy to control the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to simulate the optimal vaccination strategy to control the disease by developing an age-specific model based on the current transmission patterns of COVID-19 in Wuhan City, China.Methods: We collected two indicators of COVID-19, including illness onset data and age of confirmed case in Wuhan City, from December 2, 2019, to March 16, 2020. The reported cases were divided into four age groups: group 1, ≤ 14 years old;group 2, 15 to 44 years old;group 3, 44 to 64 years old;and group 4, ≥ 65 years old. An age-specific susceptible-exposed-symptomatic-asymptomatic-recovered/removed model was developed to estimate the transmissibility and simulate the optimal vaccination strategy. The effective reproduction number (R_(eff)) was used to estimate the transmission interaction in different age groups.Results: A total of 47 722 new cases were reported in Wuhan City from December 2, 2019, to March 16, 2020. Before the travel ban of Wuhan City, the highest transmissibility was observed among age group 2 (R_(eff) = 4.28), followed by group 2 to 3 (R_(eff) = 2.61), and group 2 to 4 (R_(eff) = 1.69). China should vaccinate at least 85% of the total population to interrupt transmission. The priority for controlling transmission should be to vaccinate 5% to 8% of individuals in age group 2 per day (ultimately vaccinated 90% of age group 2), followed by 10% of age group 3 per day (ultimately vaccinated 90% age group 3). However, the optimal vaccination strategy for reducing the disease severity identified individuals ≥ 65 years old as a priority group, followed by those 45-64 years old.Conclusions: Approximately 85% of the total population (nearly 1.2 billion people) should be vaccinated to build an immune barrier in China to safely consider removing border restrictions. Based on these results, we concluded that 90% of adults aged 15-64 years should first be vaccinated to prevent transmission in China.

Multiple 2D approaches to human sexual dimorphism of the distal end of femur

Various studies on the difference of distal femoral condyles between genders have been reported recently in order to provide anatomic information for knee prosthesis design and surgical planning in total knee arthroplasty. They also had the objective to be used as a sex recognition character, as may be needed in forensic medicine. Except for a recent 3D approach on the distal femur, most of the studies used dimensional information or aspect ratio but not shape. Our 2D study aimed to determine the size and shape variation of femoral condyles in Thais, considering age, sex and sides. One hundred and twenty-four cadaveric femurs （male 84 legs and female 40 legs） were dissected. The specimens were photographed by digital camera and images were analyzed using three geometric techniques： （i） the landmark-based method （5 landmarks）, （ii） with or without addition of 23 sliding semilandmark and （iii） the outline-based methods. From the resulting geometric coordinates, size and shape were extracted for comparisons between genders and sides. Between sides, directional asymmetry could be detected only for shape variation, and only when introducing curves in the analyses （either through the semilandmarks technique or through the outline-based one）. Non-directional asymmetry, probably fluctuating asymmetry, was detected for size, as well as for shape, in both genders. Sex discrimination was performed for each geometric technique using two classification methods： the Mahalanobis distance classification and the Maximum likelihood classification. The latter provided much more satisfactory gender validated reclassification （87%） than shape （72%）.

Computing R_(0) of dynamic models by a definition-based method

Objectives:Computing the basic reproduction number(R0)in deterministic dynamical models is a hot topic and is frequently demanded by researchers in public health.The nextgeneration methods(NGM)are widely used for such computation,however,the results of NGM are usually not to be the true R0 but only a threshold quantity with little interpretation.In this paper,a definition-based method(DBM)is proposed to solve such a problem.Methods:Start with the definition of R0,consider different states that one infected individual may develop into,and take expectations.A comparison with NGM has proceeded.Numerical verification is performed using parameters fitted by data of COVID-19 in Hunan Province.Results:DBM and NGM give identical expressions for single-host models with single-group and interactive Rij of single-host models with multi-groups,while difference arises for models partitioned into subgroups.Numerical verification showed the consistencies and differences between DBM and NGM,which supports the conclusion that R0 derived by DBM with true epidemiological interpretations are better.Conclusions:DBM is more suitable for single-host models,especially for models partitioned into subgroups.However,for multi-host dynamic models where the true R0 is failed to define,we may turn to the NGM for the threshold R0.

Shigellosis seasonality and transmission characteristics in different areas of China: A modelling study

Objective:In China,the burden of shigellosis is unevenly distributed,notably across various ages and geographical areas.Shigellosis temporal trends appear to be seasonal.We should clarify seasonal warnings and regional transmission patterns.Method:This study adopted a Logistic model to assess the seasonality and a dynamics model to compare the transmission in different areas.The next-generation matrix was used to calculate the effective reproduction number(Reff)to quantify the transmissibility.Results:In China,the rate of shigellosis fell from 35.12 cases per 100,000 people in 2005 to 7.85 cases per 100,000 people in 2017,peaking in June and August.After simulation by the Logistic model,the‘peak time’is mainly concentrated from mid-June to mid-July.China's‘early warning time’is primarily focused on from April to May.We predict the‘peak time’of shigellosis is the 6.30th month and the‘early warning time’is 3.87th month in 2021.According to the dynamics model results,the water/food transfer pathway has been mostly blocked off.The transmissibility of different regions varies greatly,such as the mean Reff of Longde County(3.76)is higher than Xiamen City(3.15),higher than Chuxiong City(2.52),and higher than Yichang City(1.70).Conclusion:The‘early warning time’for shigellosis in China is from April to May every year,and it may continue to advance in the future,such as the early warning time in 2021 is in mid-March.Furthermore,we should focus on preventing and controlling the personto-person route of shigellosis and stratified deploy prevention and control measures according to the regional transmission.

Update of transmission modelling and projections of gambiense human African trypanosomiasis in the Mandoul focus, Chad

Background:In recent years,a programme of vector control,screening and treatment of gambiense human African trypanosomiasis(gHAT)infections led to a rapid decline in cases in the Mandoul focus of Chad.To represent the biology of transmission between humans and tsetse,we previously developed a mechanistic transmission model,fitted to data between 2000 and 2013 which suggested that transmission was interrupted by 2015.The present study outlines refinements to the model to:(1)Assess whether elimination of transmission has already been achieved despite low-level case reporting;(2)quantify the role of intensified interventions in transmission reduction;and(3)predict the trajectory of gHAT in Mandoul for the next decade under different strategies.Method:Our previous gHAT transmission model for Mandoul was updated using human case data(2000-2019)and a series of model refinements.These include how diagnostic specificity is incorporated into the model and improvements to the fitting method(increased variance in observed case reporting and how underreporting and improvements to passive screening are captured).A side-by-side comparison of fitting to case data was performed between the models.Results:We estimated that passive detection rates have increased due to improvements in diagnostic availability in fixed health facilities since 2015,by 2.1-fold for stage 1 detection,and 1.5-fold for stage 2.We find that whilst the diagnostic algorithm for active screening is estimated to be highly specific(95%credible interval(CI):99.9-100%,Specificity=99.9%),the high screening and low infection levels mean that some recently reported cases with no parasitological confirmation might be false positives.We also find that the focus-wide tsetse reduction estimated through model fitting(95%CI:96.1-99.6%,Reduction=99.1%)is comparable to the reduction previously measured by the decline in tsetse catches from monitoring traps.In line with previous results,the model suggests that transmission was interrupted in 2015 due to intensified interventions.Conclusions:We recommend that additional confirmatory testing is performed in Mandoul to ensure the endgame can be carefully monitored.More specific measurement of cases,would better inform when it is safe to stop active screening and vector control,provided there is a strong passive surveillance system in place.