Objective To investigate the epidemiological characteristics and control measures of dengue fever in Zhongshan City in 2024, so as to provide insights into optimization of dengue fever control strategies in the city. Methods Data pertaining to dengue fever cases in Zhongshan City in 2024 were collected from the Infectious Disease Reporting System of China Disease Prevention and Control Information System, and the epidemiological characteristics of the cases were analyzed using a descriptive statistical method. The density of Aedes albopictus mosquito was monitored across all 23 townships (subdistricts) using Breteau index (BI) and mosquito ovitrap index (MOI) at midmonth each month from March to December 2024. In addition, the climatic characteristics, case reporting patterns, and corresponding control measures were analyzed during different phases of dengue fever epidemics in Zhongshan in 2024. Furthermore, real-time quantitative reverse transcription PCR (RT-qPCR) assay was employed to serotype the dengue virus among local dengue fever cases with unknown sources of infections. The dengue virus envelope (E) gene was sequenced using Sanger sequencing among dengue fever cases without apparent epidemiological links. A phylogenetic tree was constructed using the neighbor-joining method to infer major transmission chains during the dengue fever epi demics. Results A total of 952 dengue fever cases were reported in Zhongshan City in 2024, including 879 local cases, 57 domestically imported cases from other regions, and 16 overseas imported cases, representing the largest outbreak in nearly two decades. The first local dengue fever case was reported on July 5, and the last one was detected on December 19, with all townships and subdistricts affected. Mosquito monitoring data indicated that both MOI and BI rose rapidly from March to May, and then remained at high levels with fluctuations, and began to decline in October. The dengue fever epidemic was categorized into five distinct phases in Zhongshan, including non-epidemic, pre-epidemic, early-epidemic, peak, and receding stages. During the pre-epidemic and early-epidemic phases, key measures included enhancing sensitivity of case detection, implementing isolation and treatment of hospitalized cases, and carrying out standardized vector control measures in affected communities. In the peak phase, the strategy shifted towards targeted mosquito control in key communities and clinical rescue and treatment emphasized on “preventing severe cases and deaths”. Among 481 local cases with unknown sources of infections, RT-qPCR assay revealed that 68.8% (331/481) were infected with dengue virus type I and 31.2% (150/481) with type II among local dengue fever cases in Zhongshan City in 2024. Phylogenetic analysis revealed two major transmission chains: one originating from imported cases within Guangdong Province around Zhongshan City, and another from cases imported from Malaysia. Late detection of local dengue fever cases contributed to widespread community outbreaks. Conclusions The 2024 dengue fever epidemic in Zhongshan City was of considerable scale, which was primarily driven by imported cases from overseas and surrounding regions, leading to local community outbreaks. The epidemic began in early July, increased rapidly during August and September, peaked in October, and subsequently declined, with a trend consistent with the average pattern observed in previous high-incidence years. By implementing differentiated control measures tailored to each phase of the epidemic, the local transmission of dengue fever was successfully contained in Zhongshan City in 2024.

Objective To understand the molecular epidemiology of penicillin resistance Streptococcus pneumonia (PNSP) isolated from children in Guangzhou area to provide the experimental basis for clinical prevention and control of Streptococcus pneumonia infectious diseases.Methods Specific primers were designed according to Genebank,penicillin binding protein(PBP) genes PBP1A,PBP1B,PBP2A,PBP2B,PBP2X,PBP3 were amplified by PCR.The sequencing analysis was performed.The PCR products were digested by Hinf I,and the restriction fragment length polymorphism (RFLP) was analyzed.Results DNA of PNSP was successfully extracted,the PCR results showed that in 50 strains of PNSP,the positive rates of bacterial strains containing PBP1A,PBP1B,PBP2A,PBP2B,PBP2X and PBP3 were 48.9%,64.4%,71.1%,31.1%,40.0% and 31.1% respectively.The sequencing showed that their homologies with known sequences in GenBank were 99%,98%,100%,97%,95% and 100% respectively.Using RFLP in Hinf I showed that PBP1A,PBP1B,PBP2A and PBP3 only had one kind of genotype,PBP2B and PBP2X had two kinds of genotypes,the positive rates were 71.4%,28.6%,66.7% and 33.3% respectively.Conclusion The gene distribution of PNSP strains among children in Guangzhou is dominated by PBP2A,PBP1B and PBP1A,there are two subtypes in PBP2B,PBP2X when digested by Hinf I,in which the predominant subtype >65%.

Objective: To investigate reduction and fixation of complex acetabular fractures using three-dimensional (3D) printing technique and personalized acetabular wing-plate via lateral-rectus approach. Methods: From March to July 2016, 8 patients with complex acetabular fractures were surgically managed through 3D printing personalized acetabular wing-plate via lateral-rectus approach at Department of Orthopedics, the Third Affiliated Hospital of Southern Medical University. There were 4 male patients and 4 female patients, with an average age of 57 years (ranging from 31 to 76 years). According to Letournel-Judet classification, there were 2 anterior+ posterior hemitransverse fractures and 6 both-column fractures, without posterior wall fracture or contralateral pelvic fracture. The CT data files of acetabular fracture were imported into the computer and 3D printing technique was used to print the fractures models after reduction by digital orthopedic technique. The acetabular wing-plate was designed and printed with titanium. All fractures were treated via the lateral-rectus approach in a horizontal position after general anesthesia. The anterior column and the quadrilateral surface fractures were fixed by 3D printing personalized acetabular wing-plate, and the posterior column fractures were reduction and fixed by antegrade lag screws under direct vision. Results: All the 8 cases underwent the operation successfully. Postoperative X-ray and CT examination showed excellent or good reduction of anterior and posterior column, without any operation complications. Only 1 case with 75 years old was found screw loosening in the pubic bone with osteoporosis after 1 month′s follow-up, who didn′t accept any treatment because the patient didn′t feel discomfort. According to the Matta radiological evaluation, the reduction of the acetabular fracture was rated as excellent in 3 cases, good in 4 cases and fair in 1 case. All patients were followed up for 3 to 6 months and all patients had achieved bone union. According to the modified Merle D′Aubigné and Postel scoring system, 5 cases were excellent, 2 cases were good, 1 case was fair. Conclusions Surgical management of complex acetabular fracture via lateral-rectus approach combine with 3D printing personalized acetabular wing-plate can effectively improve reduction quality and fixation effect. It will be truly accurate, personalized and minimally invasive.