Outbreak, Surveillance, Investigation & Response (OSIR) Journal

The Epidemiologist’s Compass: Counting, Comparing, Communication, Collaboration, Context, Control, and Confidence

Alden Henderson — Wed, 24 Jun 2026 00:00:00 +0700

The Grammar of Science: B&I Before AI—Bias and Inference Still Matter

Jaranit Kaewkungwal — Wed, 24 Jun 2026 00:00:00 +0700

Health-seeking Behaviors of Caregivers following Non-fatal Injuries in Rural Children at a Sub-district of Bangladesh, 2018

Nawroz Afreen, Mehejabin Nurunnahar, Meerjady Sabrina Flora — Fri, 26 Jun 2026 00:00:00 +0700

Objectives: Understanding health-seeking behaviors of caregivers following non-fatal child injuries is necessary for child-injury prevention programs to develop effective interventions. This cross-sectional study aims to provide evidence on health-seeking practices in Bangladesh.

Methods: Data were previously collected in a survey study conducted between May and June 2018 among children aged less than 18 years from a selected sub-district of Bangladesh. Cluster sampling identified mothers or caregivers to be interviewed using a pretested semi-structured questionnaire. Health-seeking responses, including first aid and subsequent treatments, were obtained only for injured children, categorized as ‘minor’ and ‘major’.

Results: Of 918 children, the prevalence of major (n=22) and minor (n=68) injuries was 2.4% and 7.4%, respectively. All but one child received first aid or other forms of treatment. Among those who had major injuries, 77% received first aid, mostly from relatives (47%) or a doctor/trained health care worker (HCW) (41%); further treatment was pursued for 64%, and 18% were hospitalized. Among those with minor injuries, 90% received first aid, primarily from a relative (54%) or an unqualified HCW (25.5%); 60% sought further treatment, and 3% were hospitalized. Unqualified HCWs continued treatment for 50% of those with major and 71% of those with minor injuries. Caregivers applied diverse substances such as oil, water, toothpaste, ointment, or leaves as first aid, regardless of injury type and pattern.

Public Health Recommendations: This study identified nearly similar first aid practices as seen earlier, with treatment adherence more towards non-qualified HCWs. Inclusion of first aid knowledge and health-seeking behaviors in prevention programs, and qualitative studies for understanding of treatment adherence behavior are recommended.

Investigation of a 2021 Diarrheal Outbreak in a Coastal Sub-district of Bangladesh and Its Seasonal Pattern

Tue, 30 Jun 2026 00:00:00 +0700

Objectives: Diarrhea is a major health problem in Barisal, a coastal division of southern Bangladesh. In April 2021 a diarrheal outbreak was notified from Barisal health authorities. An investigation team was deployed to describe demographic characteristics and seasonal patterns, identify risk factors of diarrhea in the district, and implement control measures.

Methods: We analyzed seasonality using district health information system for the period 2018–2021 and conducted a matched case-control study in Bakerganj, the most affected sub-district. Cases were residents reporting ≥3 loose watery stools within 24 hours during 18 Apr 2021–1 May 2021. Controls were randomly selected from neighbors of a case without any diarrheal illness. Descriptive statistics were used to summarize demographic characteristics and seasonal trends, and multivariable conditional logistic regression was used to assess associations between potential risk factors and diarrheal illness.

Results: A total of 1,027 diarrheal cases were identified during the outbreak in Bakerganj. Cases increased annually in March (pre-monsoon season) and declined from June (monsoon season). We enrolled 66 cases and 132 matched controls. Drinking untreated surface water (adjusted odds ratio [AOR] 11.6, 95% confidence interval [CI] 2.4–56.3), preparing overnight fermented rice (AOR 2.5, 95% CI 1.1–5.3), and performing ablution (AOR 2.4, 95% CI 1.0–5.9) were significant risk factors. Using surface water treated by aluminum potassium sulfate was protective (AOR 0.3, 95% CI 0.1–0.7). Among stool samples, 27% (20/75) tested positive for Vibrio cholerae by rapid diagnostic test and 29% (11/38) by culture; 5 of 8 surface water samples tested were positive.

Public Health Recommendations: This outbreak occurred before the monsoon and was linked to untreated surface water for drinking and household activities. Public health authorities should implement preventive measures to ensure safe drinking water and distribute sufficient amounts of aluminum potassium sulfate to treat surface water before the annual surge.

Bio-behavioral Survey of HIV, Syphilis, HBV, and HCV Prevalence, Drug Use, Sexual Behavior, Knowledge, and Stigma among People who Inject Drugs in Thailand: A Respondent-driven Sampling, November 2022 to March 2023

Tue, 30 Jun 2026 00:00:00 +0700

Objectives: People who inject drugs (PWIDs) are a vulnerable population facing multiple public health challenges. We aimed to estimate the prevalence of sexually transmitted infections (STIs) and bloodborne diseases, and assess drug behavior, sexual behavior, knowledge of STIs, and stigma among PWIDs.

Methods: A cross-sectional survey using respondent-driven sampling was conducted in three regions of Thailand from November 2022 to March 2023. We collected data on HIV, syphilis, hepatitis B virus (HBV), and hepatitis C virus (HCV) testing, drug use and injection practices, sexual behavior, knowledge of STIs, and stigma.

Results: Among 1,015 PWIDs, the prevalence of HIV, syphilis, HBV, and HCV was 8.2%, 3.3%, 6.4%, and 34.8%, respectively. Heroin was the most commonly injected drug, and the age of heroin initiation was 14 years or below. Over 70% reported using a new needle at each use; however, in Chiang Mai Province the rate was 46.0%. Treatment was sought and received by 69.2% of respondents. While 77.3% reported being sexually active, only 32.6% consistently used condoms, and 48.4% reported using drugs before having sex. Screening for HIV and other STIs were 59.9% and 37.3%, respectively. HIV knowledge was low at 44.0%, and less than 10% were aware of pre- and post-exposure prophylaxis. Stigmatization within the family was reported by 33.2% and 14.8% avoided accessing healthcare.

Public Health Recommendations: Our findings indicate that STIs remain a significant issue in Thailand. PWIDs demonstrated suboptimal rates of using clean needles, seeking treatment, and knowledge about prevention practices. Recommendations include strengthening harm reduction, expanding screening, improving prevention education, and enhancing healthcare access.

Phylogenetic and Spatial Dynamics of Rabies Virus in Thailand, 1998–2014: A Retrospective Analysis Using MicrobeTrace

Bopit Puyati, Nipan Rongkhakulpipa — Tue, 30 Jun 2026 00:00:00 +0700

Objectives: Rabies remains an important zoonotic disease in Thailand despite long-standing vaccination programs. Understanding long-term viral circulation patterns is essential to support surveillance and control.

Methods: We conducted a retrospective molecular epidemiological analysis of rabies virus (RABV) in Thailand using 307 nucleotide sequences collected between 1998–2002 and 2011–2014. Sequences were aligned using Multiple Alignment using Fast Fourier Transform (MAFFT). Phylogenetic analysis was performed using neighbor-joining method in Unipro UGENE software, and the resulting trees were visualized using iTOL. Molecular networks were constructed in MicrobeTrace using a genetic distance threshold of 0.015. Spatial and temporal patterns were mapped using QGIS.

Results: Phylogenetic and molecular network analyses consistently classified RABV into four genetic clusters. Clusters 1–3 belonged to the Southeast Asia clade, while Cluster 4 was related to the China clade. Cluster 1 showed widespread geographic distribution, persistent circulation, and high network connectivity, indicating endemic maintenance. Cluster 2 was detected throughout the study period across multiple regions but exhibited network degree values below the median, suggesting more fragmented transmission. Cluster 3 was detected only during the early study period (1998–2002), indicating limited circulation. Cluster 4 emerged during the later period (2011–2014) and was geographically confined to northern and upper northeastern border provinces.

Public Health Recommendations: This study highlights the value of integrating phylogenetic, molecular network, and spatial analyses to better characterize rabies transmission dynamics. The findings support strengthening targeted surveillance in high connectivity and border areas, sustaining mass dog vaccination, and enhancing cross border collaboration within a One Health framework.

Urinary Iodine Status and Associated Factors among Children Aged 3–5 Years and the Elderly in Thailand, 2023–2025

Tue, 30 Jun 2026 00:00:00 +0700

Objectives: To assess the iodine status and identify associated dietary factors among children aged 3–5 years and adults aged ≥60 years in Thailand within the context of current national fortification policies.

Methods: A national cross-sectional survey from 2023 to 2025 was conducted using multi-stage cluster sampling across 77 provinces. Spot urinary iodine concentrations (UIC) were measured in 11,028 children and 11,183 older adults. Dietary behaviors were assessed via questionnaires and analyzed using multivariable linear regression to identify independent predictors of UIC while adjusting for socioeconomic and demographic confounders.

Results: The national median UIC level for children aged 3–5 years was 222.0 ug/L (interquartile range (IQR) 204.4–238.9) and for older adults was 111.4 ug/L (IQR 96.2–136.0). Among children, processed food consumption was associated with higher UIC (adjusted regression coefficients (adjusted β) 17.55, 95% confidence interval (CI) 0.68 to 34.43). In older adults, a positive trend was observed between the consumption of iodine-fortified condiments and iodine status (adjusted β 10.66, 95% CI −0.24 to 21.56). Lower UIC was independently associated with advanced age (≥81 years: adjusted β −18.76, 95% CI −33.12 to −4.39), and history of kidney disease (adjusted β −27.30, 95% CI −50.76 to −3.83) and diabetes mellitus (adjusted β −10.72, 95% CI −19.94 to −1.50).

Public Health Recommendations: Adequate population-level iodine status for both groups (according to UNICEF/ICCIDD and WHO criteria), underscores the importance of universal salt iodization programs and iodine fortification policies for condiments in Thailand. Addressing regional and clinical vulnerabilities requires strict enforcement of fortification standards to ensure the consistent delivery of sufficient iodine to the population. Policies promoting dietary patterns aligned with national guidelines should also be strengthened to safeguard population-wide iodine security.

Misalignment between Influenza Vaccination Timing and Epidemic Dynamics in Thailand: A Policy Analysis, 2011–2025

Tue, 30 Jun 2026 00:00:00 +0700

Objectives: To assess the alignment between influenza vaccination timing and epidemic dynamics in Thailand and examine the implications of epidemiological variability, program design, and implementation processes for national influenza vaccination policy.

Methods: We conducted a mixed-methods policy analysis integrating a longitudinal analysis of national influenza surveillance data from 2011–2025, assessment of vaccination program performance, and a rapid systematic review of global evidence. Epidemic onset and seasonal patterns were characterized using weekly case data. Alignment between vaccination timing and epidemic onset was quantified using a lag-time metric, defined as the interval between vaccination initiation and epidemic onset.

Results: Influenza activity demonstrated increasing seasonal variability, transitioning from a single annual peak to more complex patterns with multiple waves and shifting epidemic onset. Across the 15-year study period, dual-wave or multi-wave patterns were identified in multiple years. The national vaccination program achieved consistently high delivery efficiency (>90% of allocated doses administered), although coverage remained uneven across population groups. with a median lag time of +11 weeks. In several years, including 2014, 2019, and 2025, vaccination was initiated after epidemic onset, indicating misalignment between vaccine delivery and transmission dynamics.

Public Health Recommendations: Fixed annual vaccination schedules may not provide optimal protection in settings with variable epidemic timing. Strengthening the integration of real-time surveillance data into vaccination planning is essential. Adaptive strategies, including flexible vaccination timing and region-specific approaches, should be considered to improve alignment with epidemic risk. Simple metrics such as lag-time can support routine monitoring and guide policy adjustment. These actions are critical to enhance the effectiveness of influenza control programs in Thailand and similar countries in tropical settings.