ABSTRACT
Objective: To identify the prevalence and factors of rapidly increasing childhood obesity in Haikou, China. Methods: A total of 11 497 students from 227 classes in primary and secondary schools of Haikou were surveyed by questionnaires from October 2013 to December 2014 using the Stratified Random Cluster Sampling method. Height and weight of the students were measured. A total of 8 458 children aged 7-15 years old were selected for the prevalence analyzing of overweight/obesity and 7 836 for logistic stepwise regression analysis. Results: The rate of overweight and obesity were 10.5% and 7.4%, respectively. Out of the 33 investigated factors, 17 were associated with childhood obesity (P1) and 8 beneficial factors (OR<1). Birth weight (macrosomia), parent's obesity are the top three risk factors and children's breakfast hobby (soybean milk) and food taste (sweet), favorite diet style of the family (stewing) are beneficial factors. Conclusions: The overweight/obesity rate is already at a high level and early interventions are needed. The necessary tasks are to strengthen education on parents and children with prevention knowledge, appropriately reduce the learning burden, and control the average time of watching TV to less than 3 h a day.
ABSTRACT
Objective To investigate the Blomia tropicalis breeding status in the ground dust rice collected in Haikou City. Methods Totally 17 samples of ground dust rice were collected from 10 sampling sites in Haikou City. Then 10 g of dust rice was taken from each individual sample for isolation of the mites that were made of slide specimen, and the mites were identified and classified under a microscope. Results B. tropicalis mites were found in all the 17 samples with the detection rate of 100%. A total of 1 176 heads of B. tropicalis were isolated, with an average breeding density of 6.91 heads/g. Conclusion B. tropicalis breeding status is severe in Haikou City. The effective measures should be taken to prevent and control the harm associated with B. tropicalis contamination.
ABSTRACT
Objective To investigate the resistance to deltamethrin and permethrin in Aedes albopictus in Haikou City, and to detect the knockdown resistance (kdr) mutants of A. albopictus, elucidating the association of resistant phenotype with kdr mutation. Methods The A. albopictus samples were collected from Xinfu Island, Longtang Town, Shishan Town, Baishamen Park, and the flower market in Haikou City. Their susceptibility to deltamethrin and permethrin was tested by larval bioassay. The resistance level was determined by the R/S ratio. The kdr gene was amplified and analyzed, and the relationship between the resistant phenotype and kdr mutation was determined by Chi-square test. Results The A. albopictus samples from the flower market and Baishamen Park showed resistance to deltamethrin and permethrin, of which the flower market population had an R/S ratio of up to 436.36, indicating a high level of resistance. The A. albopictus samples from Longtang Town and Shishan Town were sensitive to permethrin, but had low (R/S ratio, 9.09) and moderate (18.18) degrees of resistance to deltamethrin, respectively. The Xinfu Island population was sensitive to both deltamethrin and permethrin. The codon 1 534 kdr was detected point mutations among 317 A. albopictus samples, with two mutant alleles, TGC/C and TCC/S. The five genotypes were wild-type TTC/TTC (frequency, 62.15%), wild/mutant heterozygous TTC/TGC (0.63%) and TTC/TCC (16.09%), homozygous mutant TCC/TCC (20.82%), and mutant heterozygous TGC/TCC (0.32%). Chi-square test revealed significant differences in the frequency of kdr mutant genotype between A. albopictu sensitive to the insecticides (31.97%) and those resistant to the insecticides (42.94%), P <0.05. Conclusion Some A. albopictus populations in Haikou City have developed resistance to both deltamethrin and permethrin. The resistant phenotype and kdr mutant genotype are closely associated. This study has also discovered for the first time the novel TCC/S point mutation of kdr.