BackgroundHuman landing catch (HLC) is the most efficient method for Aedes monitoring, but it is not ethical due to its high risk of human exposure to pathogens. We designed trials to assess the performance of an alternative human-baited double net trap (HDN) for field Aedes albopictus monitoring compared with the standard HLC.MethodsOutdoor HDN and HLC catches were conducted simultaneously at 15 field sites on two sunny days in mid-July and August. The tests were performed 3 h apart: an early morning period (7:30–8:30 h), a pre-sunset period (16:30–17:30 h) and a post-sunset period (18:30–19:30 h). A total of 90 comparisons were made between the two methods. Field comparisons were designed to minimize half-hour bias and human-bait attraction bias.ResultsTwo mosquito species were collected by HDN and HLC, with the predominated species being Ae. albopictus (HDN: n = 1325, 97.35% of total; HLC: n = 531, 92.51% of total). A small proportion were adults of the Culex pipiens complex (HDN: n = 36, 2.65% of total; HLC: n = 43, 7.49% of total). Although the mean Ae. albopictus catch per hour of HLC was significantly higher than HDN (14.72 vs 5.90 per h, t(178) = 3.151, P = 0.003), there were significant positive spatial and temporal correlations between HLC and HDN for Ae. albopictus sampling among different sites and hours (r(90) = 0.785, P < 0.001; r(90) = 0.785, P < 0.001). Both methods proved that Ae. albopictus was most active during the hours before sunset and least active after sunset. No significant variation was observed in Ae. albopictus catch size of HDN between groups of more attractive and less attractive humans (3.38 vs 2.51 per 30 min, t(88) = 1.283, P = 0.201).ConclusionsWith moderate sampling efficiency, significantly positive spatial correlation with HLC, and less human-bait attraction bias, HDN appears to be a safer alternative to HLC for Ae. albopictus monitoring in Shanghai. With mosquito activity peaking in the pre-sunset hours, Ae. albopictus catches of HDN should be performed in the hours before dark. The trap design could be improved to make it more portable and easier for field operation.

BackgroundH7N9 continues to cause human infections and remains a pandemic concern. Understanding the economic impacts of this novel disease is important for making decisions on health resource allocation, including infectious disease prevention and control investment. However, there are limited data on such impacts.MethodsHospitalized laboratory-confirmed H7N9 patients or their families in Jiangsu Province of China were interviewed. Patients’ direct medical costs of hospitalization were derived from their hospital bills. A generalized linear model was employed to estimate the mean direct medical costs of patients with different characteristics.ResultsThe mean direct cost of hospitalization for H7N9 was estimated to be ¥ 71 060 (95 % CI, 48 180–104 820), i.e., US$ 10 996 (95 % CI, 7 455–16 220), and was ¥12 060 (US$ 1 861), ¥136 120 (US$ 21 001) and ¥218 610 (US$ 33 728) for those who had mild or severe symptoms or who died, respectively. The principal components of the total fees differed among patients with different disease severity, although medication fees were always the largest contributors. Disease severity, proportion of reimbursement and family member monthly average income were identified as the key factors that contributed to a patient’s direct medical cost of hospitalization.ConclusionsThe direct medical costs of hospitalized patients with H7N9 are significant, and far surpass the annual per capita income of Jiangsu Province, China. The influencing factors identified should be taken into account when developing related health insurance policies and making health resource allocation.Trial registrationNot applicable. This is a survey study with no health care intervention implemented on human participants.Electronic supplementary materialThe online version of this article (doi:10.1186/s40249-016-0170-5) contains supplementary material, which is available to authorized users.

We investigated an outbreak of COVID-19 infection, which was traced back to a bathing pool at an entertainment venue, to explore the epidemiology of the outbreak, understand the transmissibility of the virus and analyse the influencing factors. Contact investigation and management were conducted to identify potential cases. Epidemiological investigation was carried out to determine the epidemiological and demographic characteristics of the outbreak. We estimated the secondary attack rate (SAR), incubation time and time-dependent reproductive number (R t ) and explored the predisposing factors for cluster infection. The incubation time was 5.4 days and the serial interval (SI) was 4.4 days, with the rate of negative-valued SIs at 24.5%. The SAR at the bathing pool (3.3%) was relatively low due to its high temperature and humidity. The SAR was higher in the colleagues' cluster (20.5%) than in the family cluster (11.8%). Super-spreaders had a longer isolation delay time (p = .004). The R t of the cluster decreased from the highest value of 3.88 on January 27, 2020 to 1.22 on February 6. Our findings suggest that the predisposing factors of the outbreak included close contact with an infected person, airtight and crowded spaces, temperature and humidity in the space and untimely isolation of patients and quarantine of contacts at the early stage of transmission. Measures to reduce the risk of infection at these gatherings and subsequent tracking of close contacts were effective.

BackgroundThe Mosq-ovitrap (MOT) is currently used for routine surveillance of container-breeding Aedes in China. However, the effectiveness of monitoring Aedes albopictus using the MOT and other mosquito monitoring methods, such as the Ovitrap (OT) and the CO2-light trap (CLT), have not been extensively compared. Moreover, little is known about the spatial-temporal correlations of eggs with adult Ae. albopictus abundance among these three types of traps.MethodsComparative field evaluation of MOT, OT and CLT for Ae. albopictus monitoring was conducted simultaneously at two city parks and three residential neighborhoods in downtown Shanghai for 8 months from April 21 to December 21, 2017.ResultsSignificantly more Ae. albopictus eggs were collected from both MOTs and OTs when traps remained in the field for 10 d or 7 d compared with 3 d (MOT: 50.16, 34.15 vs. 12.38 per trap, P < 0.001; OT: 3.98, 2.92 vs. 0.63 per trap, P < 0.001). Egg collections of MOTs were significantly greater than OTs for all three exposure durations (Percent positive: X2 = 72.251, 52.420 and 51.429, P value all < 0.001; egg collections: t = 8.068, 8.517 and 10.021, P value all <0.001). Significant temporal correlations were observed between yields of MOT and CLT in all sampling locations and 3 different MOT exposure durations (correlation coefficient r ranged from 0.439 to 0.850, P values all < 0.05). However, great variation was found in the spatial distributions of Ae. albopictus density between MOT and CLT. MOT considerably underestimated Ae. albopictus abundances in areas with high Ae. albopictus density (>25.56 per day ⋅ trap by CLT).ConclusionThe MOT was more efficient than the OT in percent positive scores and egg collections of Ae. albopictus. The minimum length of time that MOTs are deployed in the field should not be less than 7 d, as Ae. albopictus collections during this period were much greater than for 3 d of monitoring. MOT considerably underestimated Ae. albopictus abundance in areas with high Aedes albopictus density compared to CLT. In areas with moderate Aedes albopictus densities, MOT results were significantly correlated with CLT catches.

In the context of global warming, extreme drought climate events show a trend of frequent occurrence. Studying the relationship between climate change and drought disasters by using the performance characteristics of climate change has become a new strategic focus of global change science. In this paper, we collected meteorological data from 14 meteorological stations from 1956 to 2015 in Heilongjiang Province and used a standard precipitation index (SPI) of meteorological drought to analyze temporal and spatial characteristics of droughts in the province. Multiple methods such as Linear regression analysis, Mann-Kendall trend test and Kriging interpolation were applied and analyzed to reveal temporal and spatial distribution patterns of drought frequency and drought intensity in different parts of the province. The results show that: (1) the precipitation in Heilongjiang Province has shown a downward trend in the past 60 years and the correlation between the monthly average precipitation and the monthly mean temperature is also apparent. (2) Since 1990s, the intensity of higher drought has escalated in the whole province and has gradually strengthened from south to north. (3) The frequency distribution of drought is the lowest in the central and southern regions, and the highest in the west. (4) The uneven precipitation, sandstorm and uneven distribution of evaporation caused by the monsoon in Heilongjiang Province are the main meteorological factors for the formation of drought in the province.