Scarlet Fever Research Articles

Epidemiological Characteristics and Trends of Scarlet Fever in Zhejiang Province of China: Population-Based Surveillance during 2004-2022.

Over the past two decades, scarlet fever has resurged in some countries or areas. Nationwide nonpharmaceutical interventions changed the patterns of other infectious diseases, but its effects on the spread of scarlet fever were rarely studied. This study aimed to evaluate the changes in scarlet fever incidence in Zhejiang Province, China, before and during the COVID-19 pandemic periods and to provide references for scarlet fever prevention and control. Scarlet fever surveillance data in Zhejiang, China (2004-2022), were analyzed in three stages. Two-sample z test, ANOVA, and Tukey's test were used to compare and analyze the characteristics of disease spread at different stages. The ARIMA model was used to predict the overall trend. The data were obtained from the National Infectious Disease Reporting Information System. A total of 28,652 cases of scarlet fever were reported across Zhejiang Province during the study period, with the lowest average monthly incidences in 2020 (0.111/100,000). The predominant areas affected were the northern and central regions of Zhejiang, and all regions of Zhejiang experienced a decrease in incidence in 2020. The steepest decline in incidence in 2020 was found in children aged 0-4 years (67.3% decrease from 23.8/100,000 to 7.8/100,000). The seasonal pattern changed, with peak occurrences in April to June and November to January during 2004-2019 and 2021 and a peak in January in 2020. The median duration from diagnosis to confirmation was highest before COVID-19 (4 days); however, it decreased to 1 day in 2020-2022, matching the other two medians. In 2020, Zhejiang experienced an unprecedented decrease in scarlet fever, with the lowest incidence in nearly 18 years, but it rebounded in 2021 and 2022. The seasonal epidemiologic characteristics of scarlet fever also changed with the COVID-19 outbreaks. This suggested that nationwide nonpharmaceutical interventions greatly depressed the spread of scarlet fever. With the relaxation of non-pharmaceutical intervention restrictions, scarlet fever may reappear. Government policymakers should prioritize the control of future scarlet fever outbreaks for public health.

Деструктивные пневмонии у детей глазами телеконсультанта

Aim. To study problems that pediatricians face in the management of necrotizing pneumonia, and to show ways to its optimization. Materials and methods. Necrotizing pneumonia is a serious disease that causes difficulties in the choice of antibiotics, indications for pleural interventions and termination of the therapy. Although mostly pneumococcal, pneumonias with purulent cavities and methapneumonic pleurisy (immunopathologic in its origin) are clinically resistance to antimicrobials, and it is taken by pediatricians as indications for changing antibiotics and pleural taps. Hence the importance of studying the prevalent tactics. We conducted analysis of 52 tele-requests for children with pulmonary consolidation and air-filled cavities. Its share among all “general pediatric” requests increased from 5% in 2021–2022 to 18% in 2023–2024. Of 52 patients 43 had also pleural effusions, 11 — pneumothorax. Pneumonia followed measles in 6 children, pertussis in 3, scarlet fever — in 1. All diagnostic and curative actions were compared to Clinical guidelines. Results. In all instances conditions for hospital care (including intensive) were generally adequate, diagnostic activities were often redundant (nonrelevant analyses, multiple computer tomography instead of X-ray). Only 16 patients were started on cephtriiaxone and amoxicillin/ clavulanate recommended by Clinical guides, the rest received reserve antibiotics. All patients received the 2nd course (combinations of the reserve antibiotics), 20 of them also the 3rd course. Steroids were given only to 3 patients. Of 43 children with pleurisy taps or drainage had 33, only 9 of them according to indications. Conclusion. Pediatricians are not fully conversant with Clinical guides and it causes excessive administration of 2–3 courses of reserve antibiotics, unnecessary pleural interventions, infrequent use of steroid therapy that shortens the length of hospital stay. Keywords: necrotizing pneumonia, management optimization.

Characterization of group A streptococci causing invasive diseases in Sri Lanka.

Group A β haemolytic streptococcus (GAS) or Streptococcus pyogenes is a human pathogen that causes an array of infections, including pharyngitis, cellulitis, impetigo, scarlet fever, toxic shock syndrome, and necrotizing fasciitis. The present study characterizes 51 GAS isolates from invasive infections in Sri Lanka, focusing on resistance profiles, genetic determinants of resistance, and virulence markers. Isolates were tested for sensitivity to penicillin, erythromycin, clindamycin, and tetracycline. The presence of erm(A), erm(B), and mef(A) was detected in erythromycin-resistant isolates, while tet(M) was detected in the tetracycline-resistant isolates. PCR was used to identify SpeA, SpeB, SpeC, SpeF, SpeG, smez, and ssa as virulence markers. Selected GAS isolates were emm-typed using the updated CDC protocol. All 51 isolates were susceptible to penicillin. The number of isolates non-susceptible to erythromycin was 16. The commonest resistance determinant identified was erm(B) (11/16). Tetracycline non-susceptibility was found in 36 (70.6 %) isolates and 26 of them contained the tet(M) gene. Thirteen (25.5 %) isolates were resistant to both tetracycline and erythromycin, while 12 (23.5 %) isolates were sensitive to both antibiotics. The commonest virulence markers detected among the isolates were SpeB (44, 86.3 %), SpeG (36, 70.6 %), and SpeF (35, 68.6 %), while SpeJ (15, 29.4 %), SpeA (10, 19.6 %), and ssa (5,9.8 %) were less common. The emm types were diverse. In conclusion, the GAS isolates studied showed resistance to erythromycin and tetracycline, while retaining universal susceptibility to penicillin. Additionally, these isolates exhibited diverse genetic backgrounds, displaying varying patterns of virulence genes and emm types.

Polyendemics: From theory to practice

After COVID-19, there was a resurgence of viral and bacterial diseases globally. Data from January 2023 indicates a shift in infectious disease patterns, with influenza, RSV, SARS-CoV-2, and other viruses prevalent, leading to a termed “polyendemia.” Increased cases of invasive group A beta-hemolytic streptococcal disease (SBEA) and scarlet fever, particularly in children, have been reported in various countries. Several factors contribute to the rise in respiratory infections, including the concept of “immunity debt,” interactions between respiratory viruses, and potential immune dysregulation induced by SARS-CoV-2. Recent reports also highlight increased pneumonia cases in Chinese children, attributed to various respiratory viruses. The implications for clinical practice emphasize prevention, advocating safety measures, and promoting vaccination, especially for influenza and COVID-19. A new monoclonal antibody, nirsevimab, offers passive immunization against RSV. Rapid diagnostic tests for the early identification of viruses or bacteria are recommended. The pediatrician underscores the importance of precise diagnosis for epidemiological understanding and future vaccination encouragement.

Pathological profile of S.P. Botkin infectious hospital during the siege of Leningrad (1941-1944)

The results of autopsies performed in the pathological department of the Infectious Diseases Hospital named after. S.P. Botkin during the siege of Leningrad (from September 8, 1941 to January 27, 1944). The structure of diseases of the deceased varied during different periods of the siege of Leningrad. In the first period (September-December 1941), diphtheria, dysentery, measles, typhoid fever, and scarlet fever prevailed among the diseases. The most common causes of death in the second period (April-December 1942) were typhus, dysentery, tuberculosis, lobar pneumonia, and typhoid fever. Nosological structure in the third period of the blockade (January 1943 - January 1944): tuberculosis, dysentery, cachexia, lobar pneumonia, infectious jaundice. The discrepancy between clinical and morphological diagnoses is most often noted for the following nosology: pulmonary tuberculosis, typhoid fever, pneumonia, stomach and hepatopancreatobiliary cancer, measles, influenza. The first period of the blockade was distinguished by a high specific proportion of examination of children's bodies - 51.2% of all autopsies; in subsequent periods, the specific share of autopsies of deceased adults (20-59 years) increased to 76.2%. The difference in the nosological structure and age groups of those who died during different periods of the siege of Leningrad was determined by the epidemiological situation in the city, social and living conditions and medical and organizational factors. Conducted in the pathological-anatomical department of the hospital named after. S.P. Botkin during the siege of Leningrad, pathological studies made it possible to timely establish the causes of deaths and identify the peculiarities of the course of infectious diseases against the background of cachexia. Regularly held clinical and anatomical conferences contributed to the reduction of defects in the diagnosis and treatment of infectious diseases.

Investigating and Summarizing Information Resources Related to the Clinical Presentation and Diagnosis of Cutaneous Manifestations of Infectious Diseases in Patients With Skin of Color.

Patients with skin of color (SOC) present diseases differently in many circumstances, yet there is a lack of information regarding the presentation and diagnosis of cutaneous manifestations in such patients experiencing infectious diseases. Therefore, we conducted a scoping review to investigate and summarize information pertaining to the clinical presentation and diagnosis of cutaneous manifestations of infectious diseases in patients with SOC focusing on the following viral, bacterial, toxin-mediated, and infestation diseases and fungal infections: human immunodeficiency virus, shingles, impetigo, scarlet fever, Lyme disease, toxic shock syndrome, scabies, rickettsioses, and cutaneous fungal infections. This scoping review identified literature gaps regarding cutaneous manifestations of infectious diseases in patients with SOC such as a lack of visual examples and more precise descriptions of common infectious diseases. The lack of better-quality literature and educational resources describing cutaneous manifestations of infectious diseases in patients with SOC may contribute to care barriers; therefore, more research and collaboration are needed in the specialties of both infectious diseases and dermatology.

Group A streptococcal infection in the United Kingdom: an emerging threat

Within group A Streptococcus (GAS), only Streptococcus pyogenes exhibits clinical significance. GAS is typed serologically based on unique surface proteins and critical virulence factors, such as a hyaluronic acid capsule that shields GAS from phagocytosis. The burden of GAS was estimated in the last five years as 14,000 to 25,000 cases of the invasive group A streptococcal disease in the USA with an estimated death from 1,500 to 2,300 cases per year. Early in the summer of 2022 in England, there was more scarlet fever than was anticipated. Early in the current season, the number of notifications rose to unusual heights. The analysis of invasive GAS (iGAS) isolate typing data shows that this season has seen a wide variety of encoding mature M protein (emm) gene sequence types found. Therefore, public health authorities should think about initiatives to increase clinicians’ and the general public’s awareness of GAS infections and to promote their quick diagnosis, molecular testing and antibiotic susceptibility testing, and standard treatment.

Population of invasive group A streptococci isolates from a German tertiary care center is dominated by the hypertoxigenic virulent M1UK genotype.

Hypertoxigenic Streptococcus pyogenes emm1 lineage M1UK has recently been associated with upsurges of invasive infections and scarlet fever in several countries, but whole-genome sequencing surveillance data of lineages circulating in Germany is lacking. In this study, we investigated recent iGAS isolates from our laboratory at a German tertiary care center for the presence of the M1UK lineage. Whole-genome sequencing was employed to characterize a collection of 47 consecutive non-copy isolates recovered from blood cultures (21) and tissue samples (26) in our laboratory between October 2022 and April 2023. M protein gene (emm) typing distinguished 14 different emm types, with emm1 (17) being the dominant type. Single-nucleotide polymorphism (SNP) analysis confirmed the presence of all 27 SNPs characteristic for the M1UK lineage in 14 of 17 emm1 isolates. This study has shown for the first time that M1UK is present in Germany and might constitute a driving force in the observed surge of GAS infections. This observation mirrors developments in the UK and other countries and underscores the importance of WGS surveillance to understand the epidemiology of GAS.

A Review of the Effectiveness of Homoeoprophylaxis: SARS-CoV-2 Compared to Pre-COVID-19 Infectious Diseases

AbstractFrom Hahnemann's use in 1799 of Belladonna 30 to prevent scarlet fever, to the prevention of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2023, appropriate potencies of similarly 'similar' remedies have been used to prevent targeted infectious diseases. This is known to many as homeoprophylaxis (HP) or 'similar prevention.' Data from recent surveys suggest that the effectiveness of HP remedies against SARS-CoV-2 is lower compared to other infectious diseases. This review examines relevant evidence and suggests possible explanations for the emerging difference and ways to improve HP effectiveness. Evidence of HP's effectiveness against a range of infectious diseases from 1974 to 2014 is compared with evidence of HP's effectiveness against SARS-CoV-2 collected from 2020 to 2022. A summary of the evidence, describing the use of over 247,000,000 doses of HP medicines against various infectious diseases, suggests an average effectiveness of around 88%. Another summary of the evidence, describing the use of HP by several authors in 2020, 2021, and 2022 against SARS-CoV-2, shows a range of effectiveness around 70%. The reasons for apparent differences in HP effectiveness between 'traditional' infectious diseases and SARS-CoV-2 are discussed. It is suggested that these differences could have been expected, particularly due to the quality of most nosodes against SARS-CoV-2. The value of HP in comparison to coronavirus disease 2019 vaccines is also discussed, and conclusions are drawn. Appropriate HP against SARS-CoV-2 offers an option that appears to be at least as effective as vaccination, without any risk of toxic damage, but there is room for improvement.

Un… due… tre… SBEGA!

Two clinical cases of invasive Group A Streptococcus infection (iGAS) are reported, with very different and rapid evolution. The two clinical cases described reflect the increasing trend in the pediatric population between 2022 and 2023 of the incidence of scarlet fever and invasive Streptococcus infection in different European countries, the spread of which was facilitated by the lack of exposure during the pandemic period to viral and bacterial infections.

Identifying LiaFSR Residues Contributing to ExPortal Integrity and Response to Antimicrobials in Group A Streptococcus

Abstract Background Group A Streptococcus (GAS), or Streptococcus pyogenes, is responsible for a myriad of diseases (pharyngitis, scarlet fever, impetigo, toxic shock syndrome) of which several are prevalent in the pediatric population. The LiaFSR two-component regulatory system (TCS) and the ExPortal functional membrane microdomain (FMM) of GAS have been shown to coordinate the response to cell membrane stress when the bacterium is exposed to antimicrobials or antimicrobial peptides (AMPs). The ExPortal coordinates translocation and processing of secreted GAS proteins and contributes to sensing membrane. In an unstressed state, LiaF acts as an inhibitor of LiaS activity, both residing within the ExPortal. In a stressed state, such as exposure to antimicrobial agents, LiaF and S dissociate, allowing LiaS to phosphorylate LiaR, resulting in subsequent activation and expression of downstream target genes. Genomic analysis indicates a strict conservation of specific protein domains and certain amino acid residues in LiaF, S, and R, which suggests their critical involvement in the LiaFSR mechanism of action. We hypothesize that conserved amino acid residues in LiaFSR, such as the LiaF C-terminal domain (CTD) and a 3xK residue motif, are essential to ExPortal formation and maintenance and may contribute to differences in antimicrobial susceptibility and virulence. Methods Two different mutant strains were analyzed and compared to (wild-type) WT: one lacking the LiaF CTD (LiaF_∆CTD) and one mutagenized in the 3xK motif (LiaF_K91-93A). Five different assays were used to examine phenotypes associated with LiaFSR activity: SpeB protease activity through bacterial growth on milk plates, ExPortal integrity via fluorescence microscopy, diamide-induced oxidative stress tolerance, antimicrobial/antimicrobial peptide (AM/AMP) susceptibility, and a direct bactericidal assay in human blood (Lancefield). For the AM/AMP susceptibility, we tested 6 different antimicrobial agents with varying mechanisms of action: bacitracin, polymyxin B, LL-37, nisin, daptomycin, and HNP-1. Results Milk plate analysis revealed a significant decrease in SpeB production in the LiaF-∆CTD vs. WT, but no difference in LiaF-K91-93A relative to WT. During fluorescence microscopy, no significant differences were detected between foci of fluorescence of either mutant strain relative to WT. When exposed to diamide-induced oxidative stress, both mutants exhibited increased tolerance relative to WT. AM/AMP susceptibility assays did not reveal any significant differences for any antimicrobial agent between either mutant strain vs. WT. Finally, the Lancefield assay revealed a significant decrease in survival in human blood between both mutant strains and WT. Mutant strains also had significantly decreased survival relative to a strain lacking LiaF (∆LiaF). Conclusions The results of the AM/AMP susceptibility assay suggest that, unlike the LiaFSR system in Enterococcus, LiaF function does not contribute to LiaFSR-dependent susceptibility. Significant differences in survival in blood indicate that the LiaF residues studied are physiologically relevant in GAS infection. However, their exact mechanism underlying this contribution is being investigated. Future research will examine downstream gene regulation to elucidate the LiaFSR-associated mechanism of decreased survival in human blood, with the aim of defining determinants of GAS bacteremia.

Epidemiological characteristics of seven notifiable respiratory infectious diseases in the mainland of China: an analysis of national surveillance data from 2017 to 2021

BackgroundRespiratory infectious diseases (RIDs) remain a pressing public health concern, posing a significant threat to the well-being and lives of individuals. This study delves into the incidence of seven primary RIDs during the period 2017–2021, aiming to gain deeper insights into their epidemiological characteristics for the purpose of enhancing control and prevention strategies.MethodsData pertaining to seven notifiable RIDs, namely, seasonal influenza, pulmonary tuberculosis (PTB), mumps, scarlet fever, pertussis, rubella and measles, in the mainland of China between 2017 and 2021 were obtained from the National Notifiable Disease Reporting System (NNDRS). Joinpoint regression software was utilized to analyze temporal trends, while SaTScan software with a Poisson probability model was used to assess seasonal and spatial patterns.ResultsA total of 11,963,886 cases of the seven RIDs were reported during 2017–2021, and yielding a five-year average incidence rate of 170.73 per 100,000 individuals. Among these RIDs, seasonal influenza exhibited the highest average incidence rate (94.14 per 100,000), followed by PTB (55.52 per 100,000), mumps (15.16 per 100,000), scarlet fever (4.02 per 100,000), pertussis (1.10 per 100,000), rubella (0.59 per 100,000), and measles (0.21 per 100,000). Males experienced higher incidence rates across all seven RIDs. PTB incidence was notably elevated among farmers and individuals aged over 65, whereas the other RIDs primarily affected children and students under 15 years of age. The incidences of PTB and measles exhibited a declining trend from 2017 to 2021 (APC = −7.53%, P = 0.009; APC = −40.87%, P = 0.02), while the other five RIDs peaked in 2019. Concerning seasonal and spatial distribution, the seven RIDs displayed distinct characteristics, with variations observed for the same RIDs across different regions. The proportion of laboratory-confirmed cases fluctuated among the seven RIDs from 2017 to 2021, with measles and rubella exhibiting higher proportions and mumps and scarlet fever showing lower proportions.ConclusionsThe incidence of PTB and measles demonstrated a decrease in the mainland of China between 2017 and 2021, while the remaining five RIDs reached a peak in 2019. Overall, RIDs continue to pose a significant public health challenge. Urgent action is required to bolster capacity-building efforts and enhance control and prevention strategies for RIDs, taking into account regional disparities and epidemiological nuances. With the rapid advancement of high-tech solutions, the development and effective implementation of a digital/intelligent RIDs control and prevention system are imperative to facilitate precise surveillance, early warnings, and swift responses.Graphical

Difficulties in diagnosing cat scratch disease in children

Cat scratch disease (CSD), a zoonotic infection caused mainly by the bacterium Bartonella henselae (B.henselae), is widespread throughout the world. The main carriers of B.henselae are domestic cats that get infected by fleas. In humans, the disease occurs after a contact with a cat, typically through a bite or scratch from an infected animal. Difficulties in diagnosing the disease are associated with the variety of its clinical manifestations. Three clinical cases of CSD in children are presented, in two of them skin manifestations preceded common clinical symptoms such as fever and lymphadenopathy. In these patients, false diagnoses of scarlet fever and pityriasis rosea made it difficult to diagnose CSD in a timely manner. As a result, etiotropic treatment was started on days 16 and 21 of the illness, respectively. In the third case, a patient experienced abscess formation in one of the affected lymph nodes after prolonged fever for a month and regional lymphadenopathy, which necessitated surgical intervention. In all three cases, the family physicians did not ade­quately consider the epidemiological history, specifically failing to recognize the persistent, long-term contact of the children with cats. Patients received antibacterial therapy with clarithromycin, which led to clear positive dynamics and recovery. These clinical cases emphasize the importance of considering B.henselae infection in all cases of lymphadenopathy accompanied by skin rashes to ensure early diagnosis and appropriate treatment, thereby preventing complications, particularly when children have contact with cats.

Regional differences in historical diphtheria and scarlet fever notification rates in The Netherlands, 1905-1925: a spatial-temporal analysis.

We describe how rates of two frequently occurring notifiable diseases-diphtheria and scarlet fever-varied between regions of The Netherlands in the early twentieth century, and identify potential factors underlying this variation. Digitized weekly mandatory notification data for 1905-1925, municipality level, were aggregated into 27 'spatial units' defined by unique combinations of province and population density category (high: more than 4500; mid : 1250-4500; low: less than 1250 inhabitants km-2). Generalized additive regression models were fitted to estimate the associations between notification rates and population density, infant mortality rate and household income, while adjusting for temporal trends per spatial unit. Annual per capita notification rates for both diphtheria and scarlet fever tended to rise from the beginning of the period 1905-1925 until peaking around 1918/1919. Adjusted diphtheria notification rates were higher for high- and mid- compared with low-density municipalities (by 71.6 cases per 100 000, 95% confidence interval (CI) : 52.7-90.5; 39.0/100 k, 95% CI : 24.7-53.3, respectively). Scarlet fever showed similar associations with population density (35.7 cases per 100 000, 95% CI : 9.4-62.0; 21.4/100 k, 95% CI: 1.5-41.3). There was considerable spatial variation in notification rates for both diseases in early twentieth century Netherlands, which could partly be explained by factors capturing variation in living conditions and socio-economic circumstances. These findings aid understanding of contemporary respiratory infection transmission.

Stevens-Johnson syndrome: a case report of possible cephalosporin-induced cutaneous adverse reaction.

A severe medical condition known as Stevens-Johnson syndrome (SJS) is marked by a cutaneous and mucosal reaction from the use of specific medications. The prodromal illness is followed by severe mucocutaneous symptoms in this immune-mediated disease. We describe the clinical history of a 55-year-old Caucasian woman who was exposed to cephalosporins. In resource-constrained countries and hospitals where cutaneous biopsy is not readily available, it is not easy to diagnose Steven Johnson Syndrome. This is particularly true in countries where the incidence of infectious diseases such as scarlet fever and measles is high and the early symptoms of SJS can be mistaken for these conditions. We used the Naronjo scale to confirm the probable association of the drug with the syndrome. Physicians while writing prescriptions for their patients need to warn them of potential side effects and they should keep in mind conditions like Stevens-Johnson syndrome. This case report highlights the need for improved knowledge and understanding of SJS among healthcare practitioners in resource-limited communities where the prevalence of infectious diseases is high.

Early Warning and Prediction of Scarlet Fever in China Using the Baidu Search Index and Autoregressive Integrated Moving Average With Explanatory Variable (ARIMAX) Model: Time Series Analysis.

Internet-derived data and the autoregressive integrated moving average (ARIMA) and ARIMA with explanatory variable (ARIMAX) models are extensively used for infectious disease surveillance. However, the effectiveness of the Baidu search index (BSI) in predicting the incidence of scarlet fever remains uncertain. Our objective was to investigate whether a low-cost BSI monitoring system could potentially function as a valuable complement to traditional scarlet fever surveillance in China. ARIMA and ARIMAX models were developed to predict the incidence of scarlet fever in China using data from the National Health Commission of the People's Republic of China between January 2011 and August 2022. The procedures included establishing a keyword database, keyword selection and filtering through Spearman rank correlation and cross-correlation analyses, construction of the scarlet fever comprehensive search index (CSI), modeling with the training sets, predicting with the testing sets, and comparing the prediction performances. The average monthly incidence of scarlet fever was 4462.17 (SD 3011.75) cases, and annual incidence exhibited an upward trend until 2019. The keyword database contained 52 keywords, but only 6 highly relevant ones were selected for modeling. A high Spearman rank correlation was observed between the scarlet fever reported cases and the scarlet fever CSI (rs=0.881). We developed the ARIMA(4,0,0)(0,1,2)(12) model, and the ARIMA(4,0,0)(0,1,2)(12) + CSI (Lag=0) and ARIMAX(1,0,2)(2,0,0)(12) models were combined with the BSI. The 3 models had a good fit and passed the residuals Ljung-Box test. The ARIMA(4,0,0)(0,1,2)(12), ARIMA(4,0,0)(0,1,2)(12) + CSI (Lag=0), and ARIMAX(1,0,2)(2,0,0)(12) models demonstrated favorable predictive capabilities, with mean absolute errors of 1692.16 (95% CI 584.88-2799.44), 1067.89 (95% CI 402.02-1733.76), and 639.75 (95% CI 188.12-1091.38), respectively; root mean squared errors of 2036.92 (95% CI 929.64-3144.20), 1224.92 (95% CI 559.04-1890.79), and 830.80 (95% CI 379.17-1282.43), respectively; and mean absolute percentage errors of 4.33% (95% CI 0.54%-8.13%), 3.36% (95% CI -0.24% to 6.96%), and 2.16% (95% CI -0.69% to 5.00%), respectively. The ARIMAX models outperformed the ARIMA models and had better prediction performances with smaller values. This study demonstrated that the BSI can be used for the early warning and prediction of scarlet fever, serving as a valuable supplement to traditional surveillance systems.

B-048 Performance Evaluation of the New Anti-Streptolysin-O Assay on Mindray BS-2800M System

Abstract Background Elevated serum concentrations of Anti- Streptolysin-O(ASO) can be used to provide serologic evidence of past or present infection by β-Hemolytic Streptococci. Increasing serum concentrations of ASO antibodies are produced in response to ASO exotoxins secreted by the bacteria. Measurement of ASO antibody levels in serum can be used as an aid in the diagnosis of diseases such as glomerulonephritis, rheumatic fever, bacterial endocarditis, tonsillitis, and scarlet fever, etc. The New ASO assay has been evaluated on Mindray BS-2800M that is an automated, high throughput, and low cross-contamination system. The evaluation of this assay included precision, linearity, dilution accuracy, interference, high dose hook, and method comparison studies. Methods The new ASO reagent contains R1 buffer and R2 with latex particles conjugated with in-house made ASO antigen. The R1 is incubated with human serum sample containing ASO antibodies for 5 min at 37°C and then R2 is added. After another 5 min of incubation, immune-aggregation complex is formed. The increased turbidity is measured at 570 nm. By constructing a six-level calibration curve (water is used as reagent blank) from the absorbances of calibrators, the ASO antibody concentration of the sample is determined. Results The precision study was run according to EP05A3 with two commercial controls (approximately 80 and 300 IU/mL) and two serum sample pools (approximately 150 and 400 IU/mL) on the Mindray BS-2800M system. The repeatability and within-lab CVs ranged from 0.8% to 2.0% and 2.0% to 6.0%, respectively. The analytical linearity of the assay was determined as from 20 IU/mL to 1000 IU/mL with the limit of blank of 2 IU/mL and limit of detection of 10 IU/mL. The dilution accuracy was evaluated by diluting high ASO level samples at upper region of assay range using saline with 5-fold and run neat and diluted samples. The deviation in recoveries between diluted sample after calculation and the neat sample was found to be less than ±10%. The new ASO assay showed <±10% interference with bilirubin (conjugated or free) up to 40 mg/dL,hemolysate hemoglobin up to 1000 mg/dL,Intralipid up to 1000 mg/dL,and Triglycerides up to1000 mg/dL. The assay on the Mindray BS-2800M system(y) correlated well with the ASO assay(x) on the Beckman AU5800 system:y = 1.01 x + 1.55(r = 0.9514,n = 95,range:50–971 IU/mL). No prozone was observed with the assay on the Mindray BS-2800M system up to the highest ASO antibody concentration of 5000 IU/mL. Conclusion We conclude that the New ASO assay with in-house developed ASO antigen raw material, when used on the Mindray BS-2800M system, can measure serum ASO antibody concentrations precisely and accurately over a broad range. It is suitable for use in routine clinical laboratories.

Streptococcus pyogenes: Pathogenesis and the Current Status of Vaccines.

Streptococcus pyogenes (group A Streptococcus; GAS), a Gram-positive coccal bacterium, poses a significant global disease burden, especially in low- and middle-income countries. Its manifestations can range from pharyngitis and skin infection to severe and aggressive diseases, such as necrotizing fasciitis and streptococcal toxic shock syndrome. At present, although GAS is still sensitive to penicillin, there are cases of treatment failure for GAS pharyngitis, and antibiotic therapy does not universally prevent subsequent disease. In addition to strengthening global molecular epidemiological surveillance and monitoring of antibiotic resistance, developing a safe and effective licensed vaccine against GAS would be the most effective way to broadly address GAS-related diseases. Over the past decades, the development of GAS vaccines has been stalled, mainly because of the wide genetic heterogeneity of GAS and the diverse autoimmune responses to GAS. With outbreaks of scarlet fever in various countries in recent years, accelerating the development of a safe and effective vaccine remains a high priority. When developing a GAS vaccine, many factors need to be considered, including the selection of antigen epitopes, avoidance of self-response, and vaccine coverage. Given the challenges in GAS vaccine development, this review describes the important virulence factors that induce disease by GAS infection and how this has influenced the progression of vaccine development efforts, focusing on several candidate vaccines that are further along in development.

Managing the deteriorating child with suspected group A Streptococcus infection.

Group A Streptococcus bacteria can cause various pyogenic infections such as tonsillitis, pharyngitis, scarlet fever, impetigo, erysipelas, cellulitis and pneumonia. Most group A Streptococcus infections in children are mild and respond positively to treatment with antibiotics. However, some children develop severe infection accompanied by complications such as sepsis and will require urgent treatment, which may include non-invasive or invasive ventilation and the administration of fluids and vasoactive agents. In some instances, for example if there are no beds available in the paediatric intensive care unit, these interventions may be undertaken in a ward setting. This article gives an overview of group A Streptococcus infection, including two rare but severe complications, streptococcal toxic shock syndrome and necrotising fasciitis. It uses a fictionalised case study to examine the management of the deteriorating child with suspected group A Streptococcus infection, including respiratory support, haemodynamic support and symptom management.

Epidemiological characteristics of common respiratory infectious diseases in children before and during the COVID-19 epidemic.

Since the outbreak of coronavirus disease 2019 (COVID-19), public's awareness of infection prevention and control has increased overall, and various prevention and control measures have been adopted. These measures may also have a certain impact on the occurrence of other infectious diseases. Therefore, we collected information on children with several respiratory infectious diseases in Jinan Children's Hospital in China from 2016 to 2022 and analyzed their changes. We collected data on age, sex and number of cases of pertussis, measles, scarlet fever, pulmonary tuberculosis, mumps and influenza, which were diagnosed by clinical and laboratory criteria, from 1 January 2016 to 31 December 2022 in Jinan Children's Hospital in Jinan, Shandong Province, China. Data on the number of people affected by these diseases in China from the Chinese Center for Disease Control and Prevention were compared. Then, we processed the data by using WPS Excel 2019 and SPSS. A total of 12,225 cases were included in this study in Jinan Children's Hospital, which consisted of 3,688 cases of pertussis (2,200 cases before COVID-19 and 1,488 during COVID-19), 680 cases of measles (650 cases before COVID-19 and 30 during COVID-19), 4,688 cases of scarlet fever (4,001 cases before COVID-19 and 687 during COVID-19), 114 cases of tuberculosis (86 cases before COVID-19 and 28 during COVID-19), 449 cases of mumps (340 cases before COVID-19 and 109 during COVID-19) and 2,606 cases of influenza (1,051 cases before COVID-19 and 1,555 during COVID-19). The numbers of children in the hospital with pertussis, measles, scarlet fever, mumps and influenza decreased substantially during COVID-19 in 2020-2022 compared with numbers in 2016-2019, while numbers of patients in China with all six respiratory infectious diseases, including pulmonary tuberculosis, declined during the pandemic. A rebound of pertussis, scarlet fever and influenza was observed in 2021 and 2022. The study found that viral pathogens such as those causing measles, mumps and influenza all decreased during the pandemic, after which influenza rebounded. Infection diseases caused by bacteria such as scarlet fever and pertussis also decreased during COVID-19, and then a rebound occurred. However, tuberculosis stayed relatively constant.