Kali Tileukhanov

Background: Syphilis, caused by Treponema pallidum , remains a major sexually transmitted infection and a public-health concern because of sustained incidence, the risk of severe complications, and vertical transmission. For Kazakhstan and Central Asia, few recent studies have described national syphilis surveillance data in a way that links temporal trends to regional variation and to maternal and congenital indicators. This study describes the registered crude incidence of syphilis in Kazakhstan for 2022–2025 and its regional, maternal, congenital, clinical, and demographic distribution. Methods: We conducted a retrospective, nationwide, descriptive ecological surveillance study of official national statistical collections issued by the Ministry of Health of the Republic of Kazakhstan. Registered crude national incidence was assessed for 2022–2025. Because the 2022 administrative reform created Abai, Ulytau, and Zhetysu regions and altered the boundaries of their parent regions, directly comparable regional analyses used all 20 administrative units for 2023–2025. Analyses included descriptive statistics, the Friedman test for repeated measures, descriptive 2025 regional-to-national incidence rate ratios (IRRs), and change in regional incidence between 2023 and 2025. Maternal, congenital, clinical-form, age, and sex indicators were summarised descriptively from annual administrative Form 12-STI aggregates; maternal and congenital indicators were additionally expressed per 100,000 live births. Results: Registered crude national syphilis incidence declined from 10.5 per 100,000 population (2,055 cases) in 2022 to 8.2 per 100,000 (1,678 cases) in 2025, an overall reduction of 21.9%. Annual reductions were 12.4% in 2023, 7.6% in 2024, and 3.5% in 2025. Regional incidence remained heterogeneous in 2025 (2.7–17.7 per 100,000), but the Friedman test did not detect evidence of an overall difference in regional incidence across 2023–2025 (chi-square = 1.85, p = 0.397). In 2025, descriptive IRRs ranged from 2.16 in Karaganda to 0.33 in Kyzylorda. From 2023 to 2025, the largest reported increase was in East Kazakhstan (+ 113.5%) and the largest decrease in Kyzylorda (-79.4%). Reported syphilis cases among pregnant women decreased by 39.8%, and congenital syphilis cases decreased by 72.7% from the 2023 peak. Expressed per 100,000 live births, the congenital syphilis case rate fell from 2.84 in 2023 to 0.90 in 2025. Conclusions: The registered crude incidence of syphilis declined during 2022–2025, but substantial regional heterogeneity and persistent congenital cases remained. Because the outcome is registered surveillance incidence, the decline may partly reflect testing and reporting practices rather than transmission alone. The findings support geographically targeted surveillance and prevention, together with continued strengthening of antenatal screening.

Salmonella enterica bacteriophages are increasingly studied for bacterial biocontrol and applied microbiology. However, reliable downstream characterization depends strongly on how the phage material is purified and concentrated. This study compared five preparation strategies for a Salmonella bacteriophage: sucrose density gradient centrifugation, cesium chloride gradient centrifugation, ultrafiltration followed by lyophilization, ultrafiltration followed by ammonium sulfate precipitation, and ultrafiltration followed by trichloroacetic acid precipitation. The preparations were assessed for infectious phage recovery, total protein concentration, SDS-PAGE protein profiles, an exploratory molecular weight-based comparison with a reference phage dataset, and targeted real-time PCR screening for selected virulence-associated determinants. Ultrafiltration followed by ammonium sulfate precipitation gave the highest infectious phage recovery among the infectivity-preserving workflows and produced a consistent eight-band SDS-PAGE profile. Trichloroacetic acid precipitation produced a similar banding pattern but was considered mainly a protein precipitation method because of its denaturing effect. Cesium chloride gradient centrifugation gave the most complex SDS-PAGE profile, while ultrafiltration followed by lyophilization gave the least resolved one. Several bands fell within the molecular-mass ranges reported for proteins of related Salmonella phages, but matching by molecular mass alone cannot identify the proteins, which would require LC-MS/MS. Targeted real-time PCR did not detect sopE , sspH1 , sseI , or sopE2 . Under the conditions tested, ultrafiltration followed by ammonium sulfate precipitation gave the highest infectious recovery and a consistent SDS-PAGE pattern; these results describe how the workflows behaved here rather than showing that one method is generally superior. Key points: • Five workflows were compared for Salmonella phage purification. • Ammonium sulfate precipitation gave the highest infectious recovery. • Selected virulence-associated genes were not detected by qPCR.

Non-typhoidal Salmonella enterica continues to be a significant pathogen of global relevance. However, there is limited available comparative experimental data on the virulence of S. enterica strains that are isolated from poultry and circulating in Central Asia. This study aimed to investigate the virulence of four poultry-derived S. enterica isolates recovered in Kazakhstan using a standardized murine model of systemic infection. Outbred mice were inoculated intraperitoneally with graded bacterial doses ranging from 103 to 106 CFU and the pathogenicity was assessed by determining the median infectious dose (ID50) and median lethal dose (LD50) according to the Reed-Muench method. Systemic infection was confirmed by bacteriological re-isolation and real-time PCR. Mortality occurred primarily within 18-72 h post-inoculation and followed a clear dose-dependent pattern. Two S. enterica serovar Infantis strains showed relatively low LD50 (3.16 × 105 CFU) compared to the other isolates (1.78 × 106 CFU). This indicates relatively high virulence potential of the two S. Infantis strains compared to the others. Similar results were seen in the case of the ID50, where the same strains showed relatively high infectivity potential compared to the others. It is noteworthy that the systemic infection was seen with doses that were not lethal to the host, indicating some dissociation between virulence and infectivity potential‎‎‎.

Background: Epizootic lymphangitis (EEL), caused by Histoplasma capsulatum var. farciminosum (HCF), is a neglected equine fungal disease lacking effective vaccines. The newly developed inactivated ‘8ZH’ vaccine requires safety validation in the target species. Objectives: To evaluate the biochemical, haematological and clinical safety of the inactivated HCF ‘8ZH’ vaccine in foals. Methods: A controlled, single‐blinded study was conducted on 30 clinically healthy foals (4–6 months), randomized into vaccinated (n = 15) and control (n = 15) groups. Vaccinated animals received a 5 mL intramuscular dose (10 mg antigen, MONTANIDE GEL 01 PR adjuvant) on Day 0 and a booster on Day 21. Clinical observations (temperature, appetite, behaviour, injection site) were recorded daily. Blood was collected at baseline and on Days 7, 14, 21, 35 and 42 for biochemical, haematological and acute‐phase protein analysis. Data were analysed using repeated measures ANOVA. Results: No severe or adverse reactions were observed. Mild, transient injection‐site swelling (< 4 cm) occurred in three vaccinated foals and resolved spontaneously. All animals maintained normal temperature and appetite. AST showed a transient increase on Day 14 ( p = 0.04); WBC also rose ( p = 0.03), indicating a typical immune response. Other parameters, including ALT, GGT, creatinine, total bilirubin and acute‐phase proteins (SAA, fibrinogen, haptoglobin), remained within physiological limits. No statistically significant long‐term deviations or toxic effects were noted. Conclusions: The inactivated HCF ‘8ZH’ vaccine demonstrated a favourable safety profile in foals. These results support its continued development for use in EEL prevention programs.