ObjectiveTo investigate and analyze an outbreak of rotavirus infectious diarrhea in a prison in Chongqing Municipality, to provide a basis for adult rotavirus surveillance and prevention, and to explore the public health problems in special settings. MethodsA retrospective survey was conducted to collect and analyze data on individual cases with diarrheal disease on-site. The clinical characteristics, as well as the temporal, spatial and geographical distribution patterns of the epidemic were described. Multi-pathogen detection tests were conducted both on diarrhea cases and environmental samples, with viral genotyping performed on positive samples. A case-control analysis was performed to identify the causes of the outbreak, and an SEIR model was adopted to predict the outbreak trend and evaluate the effectiveness of interventions. ResultsA total of 65 cases were found among the inmates, with an attack rate of 2.03%. The predominant clinical manifestations included diarrhea (89.23%), watery stool (73.85%), and dehydration (18.46%). The epidemic curve indicated a “human-to-human” transmission pattern, with an average incubation period of 5‒6 days. The attack rates among chefs in the main canteen (80.00%, 8/10) and caterers (28.33%, 17/60) were significantly higher than those of other inmates （P<0.05）. Multi-pathogen polymerase chain reaction (PCR) testing detected positive for group A rotavirus, with the viral genotyping identified as G9P [8] strain. Factors such as unprotected "bare-handed" food distribution among cases with diarrhea (OR=9.512, 95%CI: 4.261‒21.234) and close contact with diarrhea cases (OR=3.656, 95%CI: 1.719‒7.778) were the possible cause of the outbreak. The SEIR model (r₀=5, α=0.3, β₁=0.08, β₂=0.04) was constructed using prison inmates as susceptible population, aiming at fitting the initial transmission trend of the outbreak, and the epidemic rate declined rapidly after intervention measures were implemented (r_t≈0). ConclusionThis rare rotavirus infection diarrhea outbreak among adults in confined settings suggests that the construction of public health prevention and control systems in prison may be overlooked. Cross infection during meal processing and distribution in the canteens of such settings is likely to be the cause of the outbreak. Given the potential neglect of public heath system construction in special settings, it is imperative to enhance the surveillance and monitoring of rotavirus and other intestinal multi-pathogens among adults, as well as the construction of public health prevention and control systems in these special settings.

Objective To investigate the distribution of urinary iodine level and its relationship with thyroid function in Tibetan adults in Lhasa. Methods Tibetan residents living in Lhasa and its surrounding countryside were recruited by the method of multistage randomized cluster sampling. Their salt iodine, drinking water iodine, urinary iodine, and thyroid function levels were detected. According to the urinary iodine level, these subjects were divided into the iodine deficiency group ( urinary iodine<100μg/L) , the iodine enough group ( urine iodine 100-199μg/L) , the iodine adequate group ( urine iodine 200-299 μg/L ) and the iodine excessive group ( urine iodine≥300μg/L) . The differences in thyroid function among various groups were compared. Results A total of 2235 subjects were included in the study. The overall level of urinary iodine was in skewed distribution, with a median ( upper and lower quartiles) of 154 (99, 229) μg/L. The proportion of subjects with insufficient iodine intake was 25.7％, while those of the enough, adequate, and excessive groups were 41. 5％, 21. 3％, and 11. 5％, respectively. There was no significant difference in urine iodine level between males and females [152(95,219)μg/L vs 155(100,232)μg/L P>0.05]. The urinary iodine levels in residents of urban were higher than those in rural residents [157(101,232)μg/L vs 140(92,200)μg/L, P<0.05]. The urinary iodine levels in the young, middle-aged, and elderly groups were 175 ( 116,256) , 136 ( 91, 200) , and 116 ( 68, 164)μg/L respectively, showing a gradual decrease in urine iodine level with aging (P<0.05). The average salt iodine content of Tibetan adults in Lhasa was 23.16 mg/kg, and that in drinking water was 4.33μg/L. There were no significant differences in TSH levels among various iodine intake groups ( P>0.05) . The levels of thyroid peroxidase antibody ( TPOAb) and thyroglobulin antibody ( TGAb) were gradually decreased with the increase of urinary iodine level (P<0.05). Conclusion More than 50％ of Tibetans are at the status of low iodine and high iodine intakes in Lhasa. Although the salt iodine content meets national standards, the drinking water iodine content is lower than that standard.