Outbreak, Surveillance, Investigation & Response (OSIR) Journal

Factors Associated with Influenza-like Illness among Inmates in an All-male Prison, Songkhla Province, Thailand, 2023

2023-12-04T13:52:24+07:00

On 9 Feb 2023, the Office of Disease Prevention and Control Region 12Songkhlawas informed of an influenza-like illness (ILI) cluster in an all-male prison in Songkhla Province. We investigated to identify the causative agent, possible sources and risk factors, and provide control measures. We conducted an active case finding by interviewing inmates and officers. Prison facilities and hygiene behaviors of inmates and officers were inspected. A retrospective cohort study was performed. Basic and effective reproductive numbers were estimated. The overall attack rate was 12.6% (474/3,648). Most cases were inmates from Wing C (80.4%). There were no severe cases or deaths. Of ten specimens tested, all were positive for influenza B/Victoria lineage, V1a.3a.2. Fifty-four percent of inmates had received influenza vaccine within the last 12 months. A mismatch between the viral strain in the vaccine and the one causing this outbreak likely contributed to the outbreak as the vaccine provided to the inmates was manufactured during the previous year's influenza season. Vaccine effectiveness was 36.2% against ILI. Having high-risk conditions (adjusted odds ratios (AOR) 2.83, 95% confidence interval (CI) 1.27–6.32) and sharing drinking glasses (AOR 2.02, 95% CI 1.21–3.36) were significant risk factors. The basic reproductive number for ILI in this outbreak was 1.36. The effective reproductive number ranged from 0.18–3.69. For effective management of ILI outbreaks in prisons, a continuous program of influenza vaccination following updated World Health Organization recommendations and a comprehensive surveillance system with rigorous respiratory illness management practices are suggested.

Association between Air Pollution Relating to Agricultural Residue Burning and Morbidity of Acute Cardiopulmonary Diseases in Upper Northern Thailand

2023-12-01T10:44:19+07:00

In Northern Thailand, increasing seasonal agricultural residue burning has led to public concern about health risks. This study aimed to examine the associations between air pollutants related to agricultural residue burning and morbidity from acute cardiopulmonary diseases in upper Northern Thailand in 2018. An ecological study was conducted. Emergency room visits and hospitalizations for chronic obstructive pulmonary disease (COPD), stroke, myocardial infarction (MI), and asthma were extracted from the National Electronic Health Record database. We interpolated air pollution data to estimate weekly pollutant concentrations, including PM₁₀, PM_2.5, carbon monoxide, nitrogen dioxide, sulfur dioxide and ozone from 1 Jan to 31 Dec 2018. Associations between air pollution and health outcomes were analyzed using a mixed effect model incorporating different lag structures. Overall pollutant concentrations exceeded WHO air quality standard levels throughout March and April, which is the end of forest burning prohibition campaign. Morbidity from COPD, stroke, MI and asthma slightly increased over March–April. For every increase in PM_2.5 level of 10 μg/m³, the relative risk of COPD, stroke, MI and asthma 1 week later was 1.10 (95% CI 1.09–1.12), 1.06 (1.05–1.08), 1.06 (1.04–1.08) and 1.06 (1.01–1.12), respectively. The effects of agricultural residue burning should be highlighted and policies should be developed to deter this practice.

Acute Gastroenteritis Outbreak in a Rural Area in Perak, Malaysia, 2022

2023-09-22T14:36:48+07:00

An outbreak of acute gastroenteritis was identified in a rural village in Perak, Malaysia, on 22 Jun 2022, following the detection of 20 cases. The Larut, Matang, and Selama District Health Office implemented public health measures to control the outbreak. We detected 25 cases during 22–24 Jun 2022, among private boarding school students and residents. Half (52%) of the cases were aged between 11 and 15 years, 68% were male, and 44% were students. Common symptoms included vomiting (88%), abdominal pain (76%), and diarrhoea (72%). No food was suspected based on food diaries, as there was no common food eaten by all cases. The epidemic curve showed a point-source pattern. Mapping of cases demonstrated that all cases used water for drinking, cooking, and other domestic usages that were supplied by the same gravity feed system. Several empty containers of carbofuran-containing insecticide and nematicide, used for agriculture, were found near the gravity feed system route at an altitude higher than its inlet. No known pathogen was isolated from the rectal swabs of cases. This acute gastroenteritis outbreak was suspected to have occurred from drinking water contaminated with chemicals such as carbofuran. After excluding other possible causes, health education to the villagers, particularly on the appropriate use of insecticides nearby the source of water supply with good cooperation from the local communities had helped successfully controlling the outbreak.

Implementation of Strategies to Prevent Mother-to-child Transmission of Hepatitis B Virus Infection, Thailand, 2016–2017

2024-02-12T08:36:54+07:00

Mother-to-child transmission (MTCT) of hepatitis B virus can cause chronic liver disease. Thailand aimed to eliminate MTCT of hepatitis B virus by 2025. Strategies include hepatitis B surface antigen (HBsAg) screening for pregnant women, antiviral therapy for infected mother, hepatitis B birth dose vaccination (HepB-BD), HBV immunoglobulin (HBIG) administration and post-vaccination serologic testing (PVST) for infants born to HBsAg-positive mother. The objectives of this study were to assess the management of HBsAg-positive mothers and their infants. We reviewed medical records of HBsAg-positive pregnant women and their infants born during 1 Jan 2016–31 Dec 2017 at 14 hospitals in seven provinces to assess the percentage of women who were tested and treated for HBV and the percentage of infants born to them who received HepB-BD, HBIG and underwent PVST. All 69,303 pregnant women were screened for HBsAg and 1,179 (1.7%) were HBsAg positive. Of 1,179 HBsAg-positive women, 219 (18.6%) were tested for hepatitis B e-antigen (HBeAg) and 85 (38.8%) were HBeAg positive; 29 (2.5%) were tested for HBV DNA and 14 (48.3%) had viral load ≥200,000 IU/mL. Of 90 women eligible for antiviral therapy, 16 (17.8%) received treatment. Among 1,144 infants with available records, HepB-BD and HBIG coverage was 99.3% and 45.8%. Of 966 children with follow-up records, 12.2% underwent PVST and all were HBsAg negative. In conclusion, while the coverage of maternal HBsAg screening and infant HepB-BD was high, few women received follow-up testing and treatment. HBIG administration for infants was low and PVST rate still needed improvement.

An Investigation of the First Non-sexual Household-transmitted Mpox Cluster with Rapid Situation Analysis of Mpox Epidemic in Thailand

2024-03-08T08:43:04+07:00

On 22 May 2023, the mpox cluster was reported in a household in Nonthaburi Province, Thailand. We investigated to confirm the outbreak and diagnoses, describe its possible linkage and source, and identify potential fomite transmission. We interviewed all cases, traced their contacts, and swabbed household surfaces for mpox. We conducted a rapid situation analysis of mpox cases in Thailand until July 2023. Three cases were confirmed within the same household involving five individuals. The first case was a sexually active male and the second case was his intimate partner. The third case was the mother of the second case. The first two cases reported no sexual activity after symptoms appeared. They both attended a shaving ceremony and engaged in activities without wearing face masks. The third case had direct contact with her son's droplets and rash and then developed symptoms, without rash and fever. No additional case was detected among participants of the ceremony. One of two other household members tested negative after developing symptom while the other was asymptomatic. Despite house cleaning with 70%-ethanol, before investigation, 18 of 27 environmental swabs tested positive, with cycle threshold values ≥30. Since situation analysis revealed no previously reported non-sexual household mpox transmission, this investigation confirmed its existence. Risk communication should address the plausibility of non-sexual transmission. Mpox symptom may occur without rash and fever, emphasizing the importance of testing suspected individuals and revising mpox investigation guidelines accordingly. Surface cleaning with 70%-ethanol may reduce fomite transmissibility.

Investigation of Risk Factors for Lumpy Skin Disease and Prevention Practices in Dak Lak, Vietnam, 2021–2022

2024-01-04T14:36:37+07:00

Lumpy skin disease is a transboundary animal disease primarily affecting cattle, and causing fever, anorexia, skin nodules, mastitis, swelling of peripheral lymph nodes, nasal discharge, watery eyes, and sometimes mortality. The disease was first detected in Vietnam in October 2020 and has spread to 55 out of 63 provinces with around 210,000 cattle and buffaloes infected. Dak Lak was one of the provinces seriously affected by the disease. A retrospective case-control study in three districts of the province was conducted to assess awareness of the disease among local livestock holders and to determine potential risk factors for disease transmission. A total of 276 holdings known to keep cattle or buffalo, including 138 cases (holdings that had at least one animal with clinical signs of the disease) and 138 controls (holdings with no clinically apparent infected animal), were investigated. The study revealed gaps in knowledge and practices among livestock holders on disease control with median scores of 8/20 for knowledge and 5/9 for practices. Vaccination against lumpy skin disease was the only risk factor significantly associated with disease transmission (adjusted odds ratio 0.39, 95% confidence interval 0.21–0.72). We recommend raising the awareness of livestock owners about the risk factors of lumpy skin disease and the importance of vaccination for better prevention and control of outbreaks.

The Grammar of Science: Chance and Magnitude

2024-03-15T13:15:03+07:00