Search

Background: A total of 79 cases of dengue fever were reported in Jining County in 2017, which is currently the northernmost focal point of local cases of dengue fever diagnosed in China. This study aimed to evaluate the density of mosquito vectors before and after the outbreak of dengue fever and provide novel reference data for the prevention and control of the disease. Methods: The light traps were set to collect mosquitoes in 2017 and 2018 to assess adult mosquito density and species composition. We used the human-baited double net trap to determine the biting rate. In addition, the Breteau index (BI) was calculated to evaluate the density of Aedes albopictus in Jining, Shandong Province. The annual average densities of Ae. albopictus in 2017 and 2018 were 0.046 and 0.066 f/t/h, respectively. Results: The average biting rate was 0.69 f/m/h in 2018. There was no significant difference found in Ae. albopictus density and biting rate in the various months. The average BI of Jining was 38.67 and 11.17, respectively. There was a statistically significant difference observed in the BI between 2017 and 2018 (Kruskal-Wallis test, χ 2  = 16.926, df  = 1, p  < 0.001). Conclusion: BI can serve as an important indicator to determine the spread of dengue fever. The findings indicted that the growing density of adult Aedes mosquitoes should be focused on, with biting rates being a potential indicator of future outbreaks. Overall, the various control measures that were implemented were effective and should be introduced in other high-risk areas.

China used to be one of the most heavily endemic countries for lymphatic filariasis (LF) in the world. Bancroftian filariasis, which is caused by the filarioid nematode Wuchereria bancrofti , is the only filariasis in Shandong Province. A total of 864 endemic counties (cities) in 16 provinces/autonomous regions/municipalities with a total population of 330 million people were at risk of infection. Shandong Province was a highly LF-endemic area in the 1950s, the epidemiological investigation of LF conducted in 1957 indicated that the disease was endemic in 74 counties and the highest microfilaria rate was up to 26%. There were ∼5 million people in the province infected with LF; among which almost 2.5 million people had lymphedema, elephantiasis, or hydrocele. Through vigorous prevention and scientific research, Shandong Province was the first to propose to treat LF with fortified diethylcarbamazine salt, more than 25 million people in the province had taken the salt, and more than 3 million people took intermittent medication. After more than 50 years of unremitting efforts, Shandong Province basically eliminated LF in 1983 and became the first province in China that successfully eradicated LF in 2004, which has played an important role in accelerating the elimination of filariasis in the country in 2007 and has made tremendous contributions to social and economic development of China. Since 1980, Shandong Province has carried out extensive international cooperation as the WHO Collaborating Center for Lymphatic Filariasis. This article is intended to share the experience in eliminating LF to other parts of the world and improve public health capacity in regions such as Africa and Oceania where the disease is still endemic for interest.

Objectives: To study the epidemiological characteristics of malaria and the effects of comprehensive malaria control implementation in Yantai, as well as to provide a scientific basis for future malaria elimination. Materials and Methods: A retrospective analysis was conducted to explore the epidemiological changes and prevention effects in Yantai from 1951 to 2017. The malaria data before 2004 were collected from paper-based annual reports, and data after 2004 came from the Infectious Diseases Information Reporting Management System. Results: A total of 81,286 malaria cases were identified in Yantai from 1957 to 2017, with two peaks occurring in 1966 (120.93/100,000) and 1970-1972 (366.12/100,000). From 1951 to 2003, the case classification was mainly Plasmodium vivax (99.80%); the first case attributed to Plasmodium falciparum occurred in 2004, and P. falciparum became the main cause of malaria after 2011. All cases reported since 2010 have been imported cases, and the last indigenous case was caused by P. vivax in 2008. A total of 129 imported cases were reported from 2010 to 2017, most of which originated in Africa (93.80%), mainly in men aged 30-49 years (68.28%). From 1951 to 1973, 73,868 cases of malaria were diagnosed with clinical symptoms, and from 1974 to 2017, 818,943 cases in fever patients were diagnosed with blood tests. Conclusions: To achieve the goal of eliminating malaria by 2020, Yantai should continue to strengthen the management of migrant population, including improving malaria surveillance for returnees and immigrants from overseas endemic areas, and continue to increase the training of medical personnel to improve their diagnostic ability.

Neurocysticercosis (NCC) has a wide spectrum of neurologic and psychiatric manifestations, including epileptic seizures, high intracranial pressure, cognitive dysfunction, and meningoencephalitis. This study presents the clinical diagnosis of 2539 NCC patients in Shandong Province, Eastern China, from 1997 to 2015. The diagnosis was based primarily on clinical features, neuroimaging, immunology, and electroencephalogramy studies. In all age groups, seizures were found to be the most common manifestation, followed by headaches, memory loss, and limb numbness, and disability. After antiparasitic treatment, computed tomography and magnetic resonance imaging showed that most of the lesions had been completely absorbed in 2106 (82.95%) patients, most of the lesions had been absorbed and a small proportion was converted into calcifications in 433 (17.05%) cases. Indirect hemagglutination (IHA), enzyme-linked immunosorbent assay (ELISA), and circulating antigen (CAg) serum tests initially gave 76.45%, 86.37%, and 80.66% positive results, respectively. After antiparasitic therapy, the positive rates of the IHA, ELISA, and CAg tests were 74.77%, 84.70%, and 3.75%, respectively, showing no significant difference in antibody levels ( p  > 0.05), but a significant difference in CAg levels ( p  < 0.01). The clinical antiparasitic treatment of NCC with three to four courses of a combination of albendazole and praziquantel achieved satisfactory therapeutic efficacy.

Japanese encephalitis (JE), which is caused by the Japanese encephalitis virus (JEV), is a zoonotic, vector-borne neurotropic disease that remains a major cause of viral encephalitis in Asia. JEV is spread to humans through mosquitoes, and its primary transmission vector is Culex tritaeniorhynchus . Mosquitoes were sampled from three collection sites: Hanzhuang town in Weishan County, Taibai Lake in Jining city, and Dongping Lake in Shandong Province, China. Pyrethroid insecticide resistance bioassays were conducted using adult mosquitoes. Cx. tritaeniorhynchus and C. pipiens pallens populations in Hanzhuang town and Dongping Lake showed resistance to pyrethroid insecticides, and populations in Taibai Lake showed incipient resistance. Coquillettidia ochracea populations in Hanzhuang town presented resistance as well, while in Taibai Lake, resistance was incipient. A total of 16,711 mosquitoes were collected, identified, and divided into 346 pools for JEV testing. Cx. tritaeniorhynchus had the advantage of being a local mosquito species. Overall, 31 (22.96) of the 135 pools of Cx. Tritaeniorhynchus were positive for JEV. The overall maximum likelihood estimates of Cx. tritaeniorhynchus , C. pipiens pallens , and Cq. ochracea indicated pooled infection rates of 5.29/1000 mosquitoes (95% confidence interval [CI] = 3.67-7.42), 1.60/1000 mosquitoes (95% CI = 0.82-2.85), and 6.39/1000 mosquitoes (95% CI = 0.39-32.23), respectively. There were no significant differences in the pooled infection rates between the districts. The resistance to pyrethroids has increased the difficulty in controlling the mosquito vectors, especially JEV-positive mosquitoes. Given the changes in the JEV transmission vectors, the spatial and temporal diversity and the dynamic variety of mosquito species, insecticide resistance and global warming have the potential to facilitate the transmission of JE to humans.

Background & Objectives: Under certain ecological circumstances, pathogens are able to rapidly adapt to new vectors. The great capacity of Plasmodium spp. to adapt to new anopheline mosquito vectors on different continents and the continuous ecological changes attributed to humans might promote their adaptation to culicine vectors, which are known to infect humans. Based on our current knowledge, it is difficult to predict whether such adaptations will occur. This study was aimed to determine the infection susceptibility of Anopheles sinensis, Culex tritaeniorhynchus and Cx. pipiens pallens to Plasmodium vivax in Shandong Province of China., Methods: The susceptibility of the three predominant species of mosquitoes -An. sinensis, Cx. tritaeniorhynchus and Cx. pipiens pallens in Shandong Province was compared with a direct membrane feeding assay with 15 batches of Shandong strain mono-infected gametocyte-containing blood collected from Plasmodium vivax-infected patients. Infectivity was measured by dissecting the midguts and salivary glands of the mosquitoes. The presence of oocysts and sporozoites was determined by microscopy at 6 and 22 days post-blood feeding., Results: From the 15 batches of mosquitoes that were fed infected blood, oocysts and sporozoites were detected only in 7th, 13th and 15th batches of infection for An. sinensis, and no oocysts or sporozoites were detected in Cx. tritaeniorhynchus or Cx. pipiens pallens. The positive rate of An. sinensis infection was 21.2, 13 and 36.3% in the three batches of mosquitoes, with an average infection rate of 23.5%., Interpretation & Conclusion: The susceptibility of An. sinensis to P. vivax was very high in Shandong Province. Cx. tritaeniorhynchus and Cx. pipiens pallens failed to exhibit susceptibility to P. vivax.

Background: The aim of the current study was to develop a marking technique as an internal marker to mark post blood meal mosquitoes by using stable phosphate isotope (32)P and determine the optimal concentration of it., Methods: An isotonic physiological saline solution, containing different concentration of radioactive isotope (32)P-labeled disodium phosphate (Na2H(32)PO4) was injected into rabbits via the jugular vein in the laboratory. Emerged Cx. pipiens were marked after feeding on rabbit. At the same time, the labeled conditions of emerged Cx. pipiens were also measured by placing feces of No. 6 rabbit into containers with mosquito larvae and pupae inside., Results: According to the label condition of Cx. pipiens after taking blood and the effect of different dosage Na2H(32)PO4 on rabbit health, the optimal concentration of radioactive isotope was determined, that is, 0.1211 mCi/kg. By placing feces of No. 6 rabbit into containers with mosquito larvae and pupae inside, the emerged mosquitoes were also labeled. Therefore, feeding mosquitoes on the animal injected with radioactive Na2H(32)PO4 was more practical for detecting and tracing mosquitoes., Conclusion: The method was less time-consuming, more sensitive and safer. This marking method will facilitate post-bloodmeal studies of mosquitoes and other blood-sucking insects.

The radioactive isotope (32)P-labeled disodium phosphate (Na₂H(32)PO₄) was injected via the jugular vein into a cow kept in a shed in Maozhuang Village, Cao Township of Shanxian County, China. Over the following 5 d, mosquitoes feeding on the cow were captured at distances up to 400 m to determine dispersal distance. The duration of radioactivity in the cow and marked mosquitoes was 10 d. The results showed that after blood feeding, Anopheles sinensis and Culex tritaeniorhynchus temporarily rested in the cattle shed and then flew outdoors. In contrast, Culex pipiens pallens remained in the cattle shed after feeding. These findings confirmed that local An. sinensis and Cx. tritaeniorhynchus were partially endophilic and tended to rest out of doors, whereas Cx. pipiens pallens was endophilic. For marked An. sinensis and Cx. tritaeniorhynchus, there was a significant tendency for dispersal to be in a northeast and east direction, probably because of the presence of heavy shading by an agricultural field, a small river for mosquito oviposition sites, and locations downwind from the blood source. The furthest flight distances for An. sinensis and Cx. tritaeniorhynchus were 210 and 240 m; therefore, control of these mosquitoes should include resting places indoors and outdoors within a radius of 250 m from confirmed cases., (© The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.)

In order to provide more efficient transduction of plasmid siRNA into target cells, develop more susceptible transduction into cancer cell types, and more easily explore application in animal experiments, we examined development of an adenoviral vector-mediated siRNA expression system and inhibition of survivin gene expression to induce the growth and apoptosis of hepatocarcinoma cells. A system of adenoviral vector-mediated siRNA expression was constructed for the survivin gene. Survivin gene expression in HepG2 cells infected with recombinant adenovirus was detected by Western blot and RT-PCR, and apoptotic cells were investigated by FAC. Western blot analysis showed that the infection of adenovirus-mediated siRNA against survivin efficiently inhibited the expression of survivin in hepatocarcinoma cells with an inhibitory rate of 66.32%. Semi-quantitative RT-PCR showed that survivin gene mRNA transcription was reduced by nearly 72.34% with a peak at 72 h. The number of apoptotic cells increased. In conclusion, results demonstrated that this adenovirus-mediated siRNA system could serve as a useful tool for both basic research on the analysis of gene function and cancer therapy applications.