Update on Canine and Human Rabies in a Rabies Endemic Situation in the Republic of Guinea

Each year, rabies kills nearly 60,000 people worldwide. Asia and Africa are the most affected. It is a public health problem because of the number of stray dogs in these nations. In Guinea, rabies is endemic and cases are often under-reported. The objective of this study was to determine the prevalence of rabies among human and animal exposures in Guinea. This was a retrospective analytical study from 2019 to 2021 conducted in the country’s human and veterinary health divisions and, primarily focused on rabies épidémiologique surveillance. The selection was based on human contact with an animal causing behavioural disorders, as well as animals put under observation following aggression on humans. The data were analysed using Epi Info version 21 software. Qualitative variables were expressed as proportions with 95% CIs, quantitative variables as mean ± standard deviation. The chi2 test and the Fischer exact test were used to compare proportions. A total of 85 veterinary facilities were visited and 100 animals registered, of which 93% were reported cases of exposure to canine rabies. One thousand five hundred and thirty-one (1531) people exposed to rabies were recorded between 2019 and 2021. During the period, the prevalence of human rabies was 0.533% [0.042 - 0.064] at 95% CI and that of canine rabies was 0.55% [0.039 - 0.061] at 95% CI. The biting animal was the dog in 97.2% of cases. Subjects over 45 years of age (57.7%) were the most affected. The prevalence of canine rabies was 0.5% compared with 0.533% for human rabies between 2019 and 2021. This low prevalence does not reflect the true extent of the phenomenon in Guinea, as few people consult health structures in the event of dog bites. Regular surveillance of the human and dog population is necessary for better rabies control in Guinea.

Molecular epidemiology, characterization of virulence factors and antibiotic resistance profile of Streptococcus agalactiae isolated from dairy farms in China and Pakistan

Streptococcus agalactiae is one of the most common pathogens that cause bovine mastitis worldwide. Identifying pathogen prevalence and virulence factors is critical for developing prevention and control approaches. Herein, 1 161 milk samples from various dairy farms in China(n=558) and Pakistan(n=603) were collected between 2019–2021 and were subjected to S. agalactiae isolation. Prevalence, serotyping, virulence genes, and antibiotic-resistant genes of S. agalactiae were evaluated by PCR assay. All isolates were characterized for haemolysis, biofilm production, cytotoxicity, adhesion, and invasion on bovine mammary epithelial cells. The prevalence of S. agalactiae-induced mastitis in cattle was found to be considerably higher in Pakistan than in China. Jiangsu and Sindh provinces had the highest area-wise prevalence in China and Pakistan, respectively. Serotypes Ia and II were prevalent in both countries, whereas serotype III was found only in Pakistan. Moreover, all isolates tested positive for PI-2b gene but negative for PI-1 and PI-2a genes. All isolates harboured cfb, cylE, hylB, and fbsB virulent genes, whereas many of them lacked bibA, rib and bca. However, the absence of bac and scp genes in Chinese isolates and cspA in Pakistani isolates was noted, while spb1 and lmb were not detected in isolates of both countries. Pakistani isolates, particularly serotype Iapositive, had a considerably higher ability to produce biofilm, haemolysis, cytotoxicity, adhesion, and invasion than Chinese isolates. Most of the isolates were phenotypically resistant to tetracycline, erythromycin, and clindamycin and genotypic resistance was confirmed by the presence of ermA, ermB, tetM and tetO genes. Our study highlights the antimicrobial resistance profile and virulence-related factors contributing to the epidemiological spread of mastitis-causing S. agalactiae in China and Pakistan. The findings may facilitate future studies designed to develop improved treatment and control strategies against this pathogen.

萃取与界面化学——Ⅰ.萃取过程中的微观界面现象

萃取是一种节能的分离技术,广泛地用于湿法冶金和有机物提取和纯化等生产过程.它的发展已有悠久的历史,自19世纪Nernst总结了简单分子的液-液两相分配平衡定律以来,萃取研究的发展十分迅速,不再局限于简单分子在液-液两相中的物理分配(如Br_2在CCl_4和水中的分配),还涉及到萃取剂与被萃取物质之间多种多样的化学作用.例如在中性络合萃取中,被萃物质分子可被萃取剂分子所溶剂化;而在酸性络合与螯合萃取反应中,被萃离子与萃取剂分子之间发生强的络合配位作用.自五六十年代以来,已对这些萃取络合反应进行了大量研究.主要是采用热力学的研究方法,测定分配系数和计算萃取络合反应的稳定常数等.在萃取工程方面,还侧重于传质、传热过程的动力学研究.

Antiviral activity of five Asian medicinal pant crude extracts against highly pathogenic H5N1 avian influenza virus

Objective: To study the antiviral properties of the five Asian medicinal plants against in vitro infection by the highly pathogenic avian influenza virus(H5N1).Methods: Crude extracts of Andrographis paniculata, Curcuma longa(C. longa),Gynostemma pentaphyllum, Kaempferia parviflora(K. parviflora), and Psidium guajava obtained by both water and ethanol extractions were investigated for their cytotoxicity in the Madin–Darby canine kidney cells. Thereafter, they were investigated in vitro for antiviral activity and cytokine response upon H5N1 virus infection.Results: The results revealed that both water and ethanol extracts of all the five studied plants showed significant antiviral activity against H5N1 virus. Among these plants,C. longa and K. parviflora showed strong anti-H5N1 activity. Thus, they were selected for further studies on their cytokine response upon virus infection. It was found that ethanol and water crude extracts of C. longa and K. parviflora induced significant upregulation of TNF-a and IFN-b m RNA expressions, suggesting their roles in the inhibition of H5N1 virus replication.Conclusions: To the best of the authors' knowledge, this study is among the earliest reports to illustrate the antiviral property of these Asian medicinal plants against the highly pathogenic avian H5N1 influenza virus. The results of this study shed light on alternative therapeutic sources for treatment of H5N1 influenza virus infection in the future.

两亲分子在溶液表面吸附层中的构象和熵模型

以吸附热力学结果为依据,建立两亲分子在溶液表面上的统计热力学的吸附熵模型,并阐明吸附层中分子的构象.首先,从吸附自由能计算两亲分子中烃基露出表面的程度;然后应用分子内转动-振动光谱数据所得的熵求出两亲分子在吸附过程中的熵变,并与偏克分子吸附熵的实验值进行比较,以鉴定结论之合理性.对于所研究的油/水界面体系,应用吸附-定向排列效应所得结果与实验定量地相符;但是对于空气/水表面,分子的构象变化使模型复杂化,因为两亲分子的碳氢链部分地暴露出水面后,获得了一定的转动和振动自由度,而且分子还存在垂直振动.

Assessing the microbiota of recycled bedding sand on a Wisconsin dairy farm

Background:Sand is often considered the preferred bedding material for dairy cows as it is thought to have lower bacterial counts than organic bedding materials and cows bedded on sand experience fewer cases of lameness and disease.Sand can also be efficiently recycled and reused,making it cost-effective.However,some studies have suggested that the residual organic material present in recycled sand can serve as a reservoir for commensal and pathogenic bacteria,although no studies have yet characterized the total bacterial community composition.Here we sought to characterize the bacterial community composition of a Wisconsin dairy farm bedding sand recycling system and its dynamics across several stages of the recycling process during both summer and winter using 16S rRNA gene amplicon sequencing.Results:Bacterial community compositions of the sand recycling system differed by both seasons and stage.Summer samples had higher richness and distinct community compositions,relative to winter samples.In both summer and winter samples,the diversity of recycled sand decreased with time drying in the recycling room.Compositionally,summer sand 14 d post-recycling was enriched in operational taxonomic units(OTUs)belonging to the genera Acinetobacter and Pseudomonas,relative to freshly washed sand and sand from cow pens.In contrast,no OTUs were found to be enriched in winter sand.The sand recycling system contained an overall core microbiota of 141 OTUs representing 68.45%±10.33%SD of the total bacterial relative abundance at each sampled stage.The 4 most abundant genera in this core microbiota included Acinetobacter,Psychrobacter,Corynebacterium,and Pseudomonas.Acinetobacter was present in greater abundance in summer samples,whereas Psychrobacter and Corynebacterium had higher relative abundances in winter samples.Pseudomonas had consistent relative abundances across both seasons.Conclusions:These findings highlight the potential of recycled bedding sand as a bacterial reservoir that warrants further study.

Seroprevalence of <i>Mycoplasma bovis</i>Infection in Dairy Cows in Ho Chi Minh, Vietnam

A cross-sectional study was carried out to investigate the seroprevalence of M. bovis. A total of 606 serum samples were randomly collected from dairy cows in Ho Chi Minh City, Vietnam. Commercial ELISA kit was used for detection of antibody to M. bovis. The results indicated that overall seroprevalence was 80.2% (486/606). There were no significant differences between regions or age categories (P > 0.05). Degree of infection to M. bovis commonly distributed at positive degree 1 (68.5%) and 2 (24.1%). Seroprevalence at highest positive degree 4 were found in District 9, District 12 and Thu Duc (6.7%, 6.3% and 1.6%, respectively). This study is the first report of seroprevalence of M. bovis in Vietnam. The results suggested that M. bovis was spreading among dairy cow populations although degree of positivity was low. It should be considered as a high risk pathogen to dairy cows in Vietnam.

Antimicrobial susceptibility testing in veterinary medicine:performance,interpretation of results,best practices and pitfalls

The performance of antimicrobial susceptibility testing(AST)of bacteria and the interpretation of AST results for bacteria isolated from animals are complex tasks which must be performed using standard published methodology and overseen by experts in clinical microbiology and in consultation with clinical pharmacologists.Otherwise,AST has significant potential for errors and mistakes.In this review,we provide guidance on how to correctly perform AST of bacteria isolated from animals and interpret the AST results.Particular emphasis is placed on the various approved or published methodologies for the different bacteria as well as the application of interpretive criteria,including clinical breakpoints and epidemiological cut-off values(ECVs/ECOFFs).Application of approved interpretive criteria and definitions of susceptible,susceptible dose-dependent,nonsusceptible,intermediate,and resistant for clinical breakpoints as well as wild-type and non-wildtype for ECVs,are explained and the difficulties resulting from the lack of approved clinical breakpoints for other bacteria,indications,and animal species is discussed.The requirement of quality controls in any AST approach is also emphasized.In addition,important parameters,often used in monitoring and surveillance studies,such as MIC50,MIC90,and testing range,are explained and criteria for the classification of bacteria as multidrug-resistant,extensively drug-resistant or pandrug-resistant are provided.Common mistakes are presented and the means to avoid them are described.To provide the most accurate AST,one must strictly adhere to approved standards or validated methodologies,like those of the Clinical and Laboratory Standards Institute or other internationally accepted AST documents and the detailed information provided therein.

A microfluidic biosensor for the diagnosis ofchronic wasting disease

Cervids are affected by a neurologic disease that is always fatal to individuals and has population effects. This disease iscalled chronic wasting disease (CWD) and is caused by a misfolded prion protein. The disease is transmitted viacontact with contaminated body fluids and tissue or exposure to the environment, such as drinking water or food.Current CWD diagnosis depends on ELISA screening of cervid lymph nodes and subsequent immunohistochemistry(IHC) confirmation of ELISA-positive results. The disease has proven to be difficult to control in part because ofsensitivity and specificity issues with the current test regimen. We have investigated an accurate, rapid, and low-costmicrofluidic microelectromechanical system (MEMS) biosensing device for the detection of CWD pathologic prions inretropharyngeal lymph nodes (RLNs), which is the current standard type of CWD diagnostic sample. The deviceconsists of three novel regions for concentrating, trapping, and detecting the prion. The detection region includes anarray of electrodes coated with a monoclonal antibody against pathologic prions. The experimental conditions wereoptimized using an engineered prion control antigen. Testing could be completed in less than 1 hour with highsensitivity and selectivity. The biosensor detected the engineered prion antigen at a 1:24 dilution, while ELISA detectedthe same antigen at a 1:8 dilution. The relative limit of detection (rLOD) of the biosensor was a 1:1000 dilution of aknown strong positive RLN sample, whereas ELISA showed a rLOD of 1:100 dilution. Thus, the biosensor was 10 timesmore sensitive than ELISA, which is the currently approved CWD diagnostic test. The biosensor’s specificity andselectivity were confirmed using known negative RPLN samples, a negative control antibody (monoclonal antibodyagainst bovine coronavirus BCV), and two negative control antigens (bluetongue virus and Epizootic hemorrhagicdisease virus). The biosensor’s ability to detect pathogenic prions was verified by testing proteinase-digested positiveRLN samples.

Genomic variation,origin tracing,and vaccine development of SARS-CoV-2:A systematic review

COVID-19 has spread globally to over 200 countries with more than 40 million confirmed cases and one million deaths as of November 1,2020.The SARS-CoV-2 virus,leading to COVID-19,shows extremely high rates of infectivity and replication,and can result in pneumonia,acute respiratory distress,or even mortality.SARS-CoV-2 has been found to continue to rapidly evolve,with several genomic variants emerging in different regions throughout the world.In addition,despite intensive study of the spike protein,its origin,and molecular mechanisms in mediating host invasion are still only partially resolved.Finally,the repertoire of drugs for COVID-19 treatment is still limited,with several candidates still under clinical trial and no effective therapeutic yet reported.Although vaccines based on either DNA/mRNA or protein have been deployed,their efficacy against emerging variants requires ongoing study,with multivalent vaccines supplanting the first-generation vaccines due to their low efficacy against new strains.Here,we provide a systematic review of studies on the epidemiology,immunological pathogenesis,molecular mechanisms,and structural biology,as well as approaches for drug or vaccine development for SARSCoV-2.