Zheng Jie Marc Ho1, Gunalan Vithia2, Ching Ging Ng3, Sebastian Maurer-Stroh4, Clive M Tan5, Jimmy Loh3, Tzer Pin Raymond Lin6, Jian Ming Vernon Lee7. 1. HQ Medical Corps, Singapore Armed Forces, 701 Transit Road #04-01, Singapore 778910; Ministry of Health, Singapore. Electronic address: marchozj@gmail.com. 2. Bioinformatics Institute, A*STAR Singapore, Singapore. 3. DSO National Laboratories, Singapore. 4. Bioinformatics Institute, A*STAR Singapore, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore; National Public Health Laboratory, College of Medicine, Singapore. 5. HQ Medical Corps, Singapore Armed Forces, 701 Transit Road #04-01, Singapore 778910. 6. National Public Health Laboratory, College of Medicine, Singapore. 7. HQ Medical Corps, Singapore Armed Forces, 701 Transit Road #04-01, Singapore 778910; Ministry of Health, Singapore.
Abstract
BACKGROUND: Simultaneous acute gastroenteritis (AGE) outbreaks occurred at two military camps. This study details the epidemiological findings, explores possible origins, and discusses preventive measures. METHODS: Investigations included attack rate surveys, symptom surveys, hygiene inspections, and the testing of water, food, and stool samples. DNA/RNA was extracted from stool samples and amplified via real-time reverse transcription PCR (RT-PCR). Partial and full-length capsid nucleotide sequences were obtained, phylogenetic relationships inferred, and homology modelling of antigenic sites performed. RESULTS: The military outbreaks involved 775 persons and were preceded by two AGE outbreaks at restaurants in the local community. The outbreak was longer and larger in the bigger camp (21 days, attack rate 15.0%) than the smaller camp (6 days, attack rate 8.3%). Of 198 stool samples, norovirus GI.2 was detected in 32.5% (larger camp) and 28.6% (smaller camp). These were essentially identical to preceding community outbreaks. Antigenic site homology modelling also showed differences between identified and more common AGE outbreak strains (norovirus GII.4). CONCLUSION: Differences observed highlight difficulties in controlling person-to-person outbreaks among large groups in close proximity (e.g., military trainees). Distinct differences in antigenic sites may have contributed to increased immunological susceptibility of the soldiers to infection.
BACKGROUND: Simultaneous acute gastroenteritis (AGE) outbreaks occurred at two military camps. This study details the epidemiological findings, explores possible origins, and discusses preventive measures. METHODS: Investigations included attack rate surveys, symptom surveys, hygiene inspections, and the testing of water, food, and stool samples. DNA/RNA was extracted from stool samples and amplified via real-time reverse transcription PCR (RT-PCR). Partial and full-length capsid nucleotide sequences were obtained, phylogenetic relationships inferred, and homology modelling of antigenic sites performed. RESULTS: The military outbreaks involved 775 persons and were preceded by two AGE outbreaks at restaurants in the local community. The outbreak was longer and larger in the bigger camp (21 days, attack rate 15.0%) than the smaller camp (6 days, attack rate 8.3%). Of 198 stool samples, norovirus GI.2 was detected in 32.5% (larger camp) and 28.6% (smaller camp). These were essentially identical to preceding community outbreaks. Antigenic site homology modelling also showed differences between identified and more common AGE outbreak strains (norovirus GII.4). CONCLUSION: Differences observed highlight difficulties in controlling person-to-person outbreaks among large groups in close proximity (e.g., military trainees). Distinct differences in antigenic sites may have contributed to increased immunological susceptibility of the soldiers to infection.
Authors: P Raj; J Tay; L W Ang; W S Tien; M Thu; P Lee; Q Y Pang; Y L Tang; K Y Lee; S Maurer-Stroh; V Gunalan; J Cutter; K T Goh Journal: Epidemiol Infect Date: 2016-10-28 Impact factor: 4.434
Authors: Freddy Jun Xian Neo; Jimmy Jin Phang Loh; Peijun Ting; Wei Xin Yeo; Christine Qiu Han Gao; Vernon Jian Ming Lee; Boon Huan Tan; Ching Ging Ng Journal: BMC Infect Dis Date: 2017-11-14 Impact factor: 3.090