ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Dengue found in tropical and sub-tropical climates worldwide is a mosquito-borne viral infection. The infection causes flu-like illness, and occasionally develops into a potentially lethal complication called severe dengue. Severe dengue is a leading cause of serious illness and death among children today, severe dengue affects most Asian and Latin American countries and has become a leading cause of hospitalization and death among children in these regions. Its prevention and control solely depends on effective vector control measures. In China, the characteristics of dengue is rapid spread, high prevalence as well as the massive susceptibility. Due to the ubiquitous distribution of vector Aedes mosquitoes, economic boost, frequent migration of people and movement of freights global warming and the prevalent dengue infection in neighboring countries, this infection has gone to its peak in Guangdong province in 2014. Local governments and agencies had gained lots of experiences and ideas in dealing with the disease outbreak. In this paper, with the domestic and foreign experiences in mosquito management we have culled and gathered, combined with our opinions formulated in the dispose of dengue outbreak, we present a review on the character of dengue epidemic, the technology applied on Aedes control, the insecticides used, the insecticides resistance, the integrated methods used in mosquito control in China and other countries. Thus, the review will provide a useful reference on dengue outbreak management and Aedes mosquito control in China.
Diseases transmitted by mosquitoes result in severe morbidity and mortality every year, and there is an urgent need to develop an effective tool to prevent the most important diseases including dengue and others. Due to rapidly developing resistance in insects and its negative impact on environment, chemical insecticide becomes increasingly difficult to be relied on for disease control. Thus a significant effort is made to develop a sustainable vector control strategy, such as Wolbachia-based vector control. Theoretically Wolbachia-based population replacement would lead to interruption of disease transmission due to the ability of Wolbachia to induce cytoplasmic incompatibility and pathogen interference. Compared with the other control tools, this Wolbachia approach is cost-effective, sustainable and environmental friendly. With field trial currently ongoing in a number of countries, Wolbachia-based vector control is now becoming one of the most promising novel tools for control of mosquito-borne diseases.
Objective To detect the infection with Bartonella henselae in Haemaphysalis longicornis. Methods Haemaphysalis longicornis captured in Lingshou county, Shijiazhuang, Hebei province, China, were divided into groups. The H. longicornis in each group was disinfected, sterilized, and grinded. Half of the grinded mixture was directly used for DNA extraction and polymerase chain reaction (PCR) analysis;the other half was inoculated onto tryptic soy agar supplemented with 5% defibrinated sheep blood followed by culturing in a 5% CO2 incubator at 37 ℃, and the suspected colonies were selected for PCR analysis. The PCR products that produced positive bands were sequenced, and the nucleotide sequences obtained were aligned with known sequences in GenBank. Results A positive band was observed in one sample from direct DNA extraction, the sequence of which was found to belong to B. henselae by alignment analysis. Positive bands were observed in two DNA samples isolated from bacterial cultures, but no results were produced from sequencing. Conclusion Haemaphysalis longicornis collected in Lingshou county, Shijiazhuang, are infected with B. henselae. This is the first detection of B. henselae infection in H. longicornis.
Objective To investigate the status of infection with Bartonella in domestic and feral cats in Beijing, China. Methods EDTA-anticoagulated blood and serum samples were collected from cats, and the relevant epidemiological information was recorded. The anticoagulated blood was diluted 1:4 in sterilized tryptic soy broth and a 100 μl aliquot was inoculated onto the brain-heart infusion agar supplemented with 5% defibrinated sheep blood followed by culturing in a 5% CO2 incubator at 37 ℃ for 45 days. Bartonella-like isolates from the culture were examined by PCR analysis using the primers for gltA, ftsZ, and ribC. The PCR products were sequenced, and homologous comparison and phylogenetic analysis were performed to identify the species of Bartonella. Indirect immunofluorescence assay was carried out to measure the titer of anti-Bartonella henselae IIFT (IgG) in the serum samples. Data obtained from the experiments and the epidemiological information collected in the field were analyzed by the SPSS 13.0 software. Results The positive rate for Bartonella culture isolates was 13.8% in the cats tested in Beijing, and all the 22 strains obtained were B. henselae. The seropositivity rate for anti-B. henselae IgG was 39.4%. The feral cats, flea-infested cats, and kittens had significantly higher positive rates for Bartonella isolates (30.4%, 36.6%, and 27.9%, respectively). The seropositivity rate for anti-B. henselae IgG in flea-infested cats (61.0%) was also significantly higher than that in uninfested cats (31.9%). Conclusion Bartonella infection is common in both domestic and feral cats in Beijing, and the species is identified to be human pathogen B. henselae. Bartonella infection in humans could be avoided by flea control and preventing flea infestation in domestic cats, and strengthening the control of feral cats.
Objective To confirm the laboratory diagnosis of dengue fever and trace the molecular origin of the pathogen in Zhejiang province, China, 2013. Methods The serum samples from the dengue fever patients were used to detect the dengue IgM antibodies and viral nucleic acids, and to isolate the virus. The envelope (E) gene of the isolated strains was amplified by RT-PCR. The amplicons were sequenced and subjected to homologous and phylogenetic analyses. Results All 18 dengue fever patients had been to endemic areas of dengue fever overseas. Fifteen (83.3%) out of 18 serum samples from the patients were positive for anti-dengue IgM, and 8 (44.4%) were positive for dengue viral nuclei acids. Six strains of Dengue virus type 1 (DV-1) and 1 strain of DV-4 were isolated. The nucleotide sequence homology of the E gene and the amino acid sequence homology were 90.9%-99.7% and 96.8%-100%, respectively, among the 6 DV-1 strains, and 91.4%-98.5% and 96.6%-99.0%, respectively, between the 6 DV-1 strains and the DV-1 stains isolated in 2004 in Zhejiang province. The phylogenetic analysis of E gene showed that the gene subtypes of DV-1 strains were genotypeⅠ (GⅠ), GⅣ and GⅤ, and the subtype of DV-4 strain was GⅠ. All the 7 strains of dengue virus isolated in 2013 had a far phylogenetic relationship with the strains isolated from 2004 to 2009 in Zhejiang province. Conclusion All the dengue fever cases in Zhejiang province in 2013 are imported from countries including Philippines, Angola, Sri Lanka, and Brazil. The DV-1 strains are derived from the subtypes in Asia, South Pacific and America/Africa. The DV-4 strain is derived from the subtype in Southeast Asia, and it is the first detection in Zhejiang province.
Objective To determine the species composition and distribution of mosquitoes and the pathogens carried in Shanghai, China, and to provide a scientific basis for establishment of local preventive measures for mosquitoes and mosquito-borne diseases. Methods Related literature of the last 20 years (1993-2013) was collected, from which relevant information was extracted, and the mosquito species and distribution and the pathogens carried by them in different investigation sites in Shanghai were analyzed. Results Anopheles sinensis, Aedes albopictus, Culex tritaeniorhynchus, Cx. pipiens pallens, and Armigeres subalbatus were the most common mosquito species in Shanghai. The diversity of species in airports and ports was significantly higher than that in other areas. Japanese encephalitis virus genotypes Ⅰ and Ⅲ were both prevalent among the mosquitoes in Shanghai. Conclusion Airports and ports are the main entrance points of mosquito invasion. There is a potential risk of dengue virus and West Nile virus when considering a large number of appropriate vectors in Shanghai. The investigation and monitoring of mosquitoes and their pathogens should be strengthened in Shanghai.
Objective To study the features of gene composition and distribution of three common plasmids among different Yersinia pestis strains. Methods The global structure of three plasmids, pMT1, pCD1, and pPCP1, in the nine Y. pestis strains with completed whole genome sequencing was comparatively analyzed by homologous alignment of coding sequences and automatic analysis using the Mauve software. Results The pMT1 of Y. pestis showed rearrangement of large gene fragments, and it was divided into four major gene blocks. The plasmid structures of pMT1 in Orientalis Biovar strain CO92, Medievalis Biovar strain KIM, and Microtus Biovar strain 91001 were different from each other. The plasmid structures of pMT1 in all the other six Antiqua Biovar strains were almost identical, yet different from those of CO92, KIM, and 91001. Plasmid pCD1 was divided into three major gene blocks;however, the global structure of the plasmid was the same among all strains except a different insertion position of IS100. The order and orientation of all coding sequences in plasmid pPCP1 were consistent in all strains. Conclusion Plasmids pCD1 and pPCP1 have conservative gene structure among different Y. pestis strains. A certain degree of variation in the plasmid structure of pMT1 has occurred during the long-term evolution of Y. pestis.
Objective To analyze the epidemic situation of hemorrhagic fever with renal syndrome (HFRS) and the population distribution and virus-carrying status of the hosts in Zhejiang province, China, in 2013, and to provide scientific evidences for establishing further prevention and control measures. Methods The descriptive epidemiological method was used to analyze the three-dimensional (time, region, and population) distribution of HFRS. Rodents were captured by night trapping in five HFRS monitoring points in Zhejiang province. Lung and serum samples were collected followed by detection of hantavirus antigen and antibody using an immunofluorescence assay, and the rodent population distribution and virus-carrying status in Zhejiang province were analyzed. Results A total of 527 HFRS cases were reported in 2013 in Zhejiang province. The incidence rate was 0.9622/100 000, resulting in a 3.89% increase compared with 2012, and no death was reported. The cases were mostly seen in five cities (Ningbo, Taizhou, Shaoxing, Quzhou and Lishui), and all the prefectural level cities had cases reported except Zhoushan. There were two peaks of incidence, one in spring (May-June) and the other in winter (around December). The high-risk age group of HFRS was between 20 and 65 years, accounting for 93.17% of the overall incidence rate (491/527). A total of 13 785 effective traps were set in the five monitoring points, and 546 rodents were captured, so the average density of rodents was 3.96%. A total of 678 rodent serum samples were collected and 80 were positive (positive rate: 11.80%). A total of 669 lung samples were collected and 44 were positive (positive rate: 6.58%). There were significant differences in the positive rate of HFRS antibody and the virus-carrying rate between the five HFRS monitoring points (χ2=30.962, P<0.05 and χ2=9.83, P<0.05, respectively). Conclusion The incidence of HFRS in Zhejiang province in 2013 is on a rising trend compared with that in 2012, and the density of host animals and virus-carrying rate are both higher. Preventive measures should be taken into consideration to control the epidemic situation.
Objective To investigate the status of rodent, livestock, and poultry carrying Yersinia enterocolitica in plague foci maintained by Citellus dauricus in Ar Horqin Banner, Chifeng, Inner Mongolia, China, and to provide scientific evidence for prevention and control of the disease and study of the plague focus. Methods Villages in the C. dauricus plague foci were chosen as the sampling centers, and the farmland and grassland in outward concentric circles were sequentially included in the sampling area. Feces, tongue roots, throat swabs, and intestinal contents of rodent, livestock, and poultry were separately collected, and different Y. enterocolitica strains were isolated, cultured, identified, and serotyped. PCR analysis was conducted to detect the toxicity genes of Y. enterocolitica. Statistical analysis was performed by chi-square test. Results A total of 3837 samples were collected from 2009 to 2012. Seventeen Y. enterocolitica strains were isolated and the overall detection rate was 0.44%. Of the 16 strains detected in 2011, 13 were from pig feces and 3 from rodent intestines. The pathogenic strain of serotype O:3 and biological type Ⅲ carrying toxicity genes ail, ystA, and rfbC was isolated from pig feces. Conclusion Pigs and rodents in Shaogen, Ar Horqin Banner, carry Y. enterocolitica. Pigs are the major carrier of pathogenic Y. enterocolitica. Further investigation of the distribution pattern of Y. enterocolitica between human and animal hosts in the area is necessary.
Objective To study and analyze the distribution and composition of floor fleas in households in west of Yunnan province, China, and to evaluate the risk of flea-borne diseases. Methods Ten counties (cities) in west of Yunnan, four villages from each of the county, and twenty households from each of the village were randomly selected, which made a total of 800 households as sampling sites. Ten water-containing plates were placed in each household for three consecutive nights. Fleas were collected every morning and species were identified under a microscope. The capture rate, flea index, species composition, and sex ratio were calculated. Results Of the 800 households, 346 (43.25% ) had floor fleas captured. A total of 24 000 plates were placed per night and 2406 fleas were captured. The capture rate was 10.03% and the flea index was 0.100. There were 5 species, 5 genera, and 3 families identified, and Pulex irritans accounted for 72.73% of all fleas captured. The female-to-male ratio was 1:0.65. Conclusion Among the floor fleas in households in west of Yunnan province, P. irritans is the predominant species. The conducive conditions and risk of flea-borne diseases still exist. To prevent the epidemic of flea-borne diseases, flea surveillance should be strengthened and flea control measures should be promptly taken.
Objective To study the changes in ecological habits of important malaria vectors in the epidemic-prone regions of malaria in Yunnan province, China. Methods Light traps were used to collect mosquitoes in households and cowsheds all night, and human landing collection was used to study the pattern of mosquito activities at night in Jinghong city, Yuanjiang county, Suijiang county, and Longling county. The host source of mosquito blood meal was identified by multiplex PCR analysis. Results A total of 44 635 mosquitoes from 18 species were collected, of which Anopheles sinensis, An. minimus, An. lesteri, An. kunmingensis, and other species accounted for 59.30% (26 468), 5.44% (2428), 0.22% (100), 3.63% (1620), and 31.41% (14 019), respectively. The peaks of night activity for different Anopheles mosquito species were as follows: between 23:00 and 00:00 for An. minimus in Jinghong, between 20:00 and 21:00 for An. sinensis in Jinghong and Yuanjiang, between 02:00 and 03:00 for An. sinensis in Suijiang, and before 22:00 for An. kunmingensis. The expected lifespans of An. sinensis, An. minimus, and An. kunmingensis were relatively long, between 0.90 and 1.00. The human blood indices for An. sinensis, An. minimus, and An. kunmingensis were 0.30, 0.50, and 0.30, respectively. Conclusion The ecological habits of An. minimus, An. sinensis, and An. kunmingensis have changed, and whether these changes lead to alterations in the endemic characteristics of malaria in those regions awaits further investigation.
Objective To study the predatory capacity of Culex fuscanus on Aedes albopictus and the relevant influencing factors. Methods Culex fuscanus and Ae. albopictus larvae were collected in the field. Densities of Cx. fuscanus and Ae. albopictus larvae were recorded and the relationship between densities and the predatory capacity of Cx. fuscanus was studied. The surviving status of Ae. albopictus at different temperature and in water inhabited by Cx. fuscanus was investigated. Results When the density of prey fell in a certain range [under 25 Ae. albopictus larvae/(Cx. fuscanus larva·d)], the daily predation by Cx. fuscanus larvae was positively correlated with the density of Ae. albopictus (R=0.942, P<0.01), and the highest number of caught Ae. albopictus larvae was 55.86, as calculated by the Holling's disc equation. When the density of prey remained consistent, the daily predation by Cx. fuscanus larvae was negatively correlated with the density of its own (R=-0.943, P<0.01). Cx. fuscanus larvae could change the quality of water to reduce the survival rate of Ae. albopictus larvae (χ2=8.661, P=0.002). Significant difference in high temperature tolerance was observed between Ae. albopictus and Ae. albopictus larvae (t=7.365, P<0.01). Conclusion The biological control capability of Cx. fuscanus on Ae. albopictus is affected by many factors including temperature and densities of Ae. albopictus and Cx. fuscanus. Further studies are needed to evaluate the actual field efficacy of biological control. Predation of Ae. albopictus by Cx. fuscanus can be used as an attempt of biological control.
Objective To identify nocturnal rodent species in the Bashang area of Hebei province, China, using DNA barcoding. Methods Liver tissue samples of nocturnal rodents were collected from the study area. The whole mice were also preserved and dissected. Genomic DNA was extracted for PCR amplification of the mitochondrial cytochrome c oxidase subunitⅠ (COⅠ) gene with consensus primers, followed by sequencing. Blast comparisons were performed between the obtained sequencing data and the DNA bar codes of other rodent species in the GenBank. A molecular evolutionary tree was built. Results All the 36 samples produced specific COⅠ gene bands by PCR amplification. The result of molecular evolutionary tree was slightly different from that of morphological identification. Skull identification revealed that the molecular evolutionary tree was correct, and the result of morphological identification was corrected. High-homology genes were not found in the GenBank for two nocturnal rodents. Since their skulls were seriously damaged, we temporally could not determine the species of these two individuals. Conclusion DNA barcoding can be used to effectively identify rodent species.
Objective To determine the toxicity of mixtures of chlorfenapyr and sulfluramid at different ratios against Chinese termites (Coptotermes formosanus) and to seek more effective mixtures of termiticides. Methods Termites continuously contacted filter paper which was treated with chlorfenapyr and sulfluramid and their mixtures at different ratios. The mortality of termites and median lethal concentration (LC50) were determined, and the co-toxicity coefficient (CTC) was calculated using the Sun Yunpei's method. Results The LC50 of chlorfenapyr and sulfluramid against termites after 96 h were 1.211 and 16.143 mg/L respectively. The CTCs of sulfluramid/chlorfenapyr mixtures at ratios of 5:1, 20:1, and 40:1 were 175.059, 154.158, and 155.829 respectively, showing a synergistic effect;the CTCs were 132.810, 116.758, 100.753, 119.261, and 82.584 when the two termiticides were mixed at ratios of 10:1, 30:1, 1:1, 1:5, and 1:20, respectively, showing an additive effect. Conclusion The different mixtures of chlorfenapyr and sulfluramid have synergistic and additive effects against C. formosanus.
Objective To investigate the repellent activities of essential oil from chestnut flower and its four active components as well as distillate against Aedes albopictus. Methods Component analysis of essential oil from chestnut flower was performed by gas chromatography-mass spectroscopy. The repellent activities of essential oil and its four active components as well as distillate against Ae. albopictus were determined using the effective protection time and repellent rate. Results Essential oil from chestnut flower mainly contained 11 compounds belonging to aldehydes, ketones, alcohols, and esters. The effective repellent times of essential oil and its individual active components (menthol, geraniol, linalool, and terpineol) were 3.00, 4.25, 6.00, 3.75, and 5.00 h, respectively. The effective repellent times of chestnut flower distillate and commercial toilet water were 0.08 and 2.25 h, respectively. These data were indicative of the strong repellent activity of essential oil from chestnut flower. The repellent activity of distillate was improved through an orthogonal experiment, with individual active components of essential oil as enhancers and 100 ml of distillate as a basic reagent. With the optimized formula, the protection time of distillate was extended to 2.50 h. Conclusion Essential oil from chestnut flower has strong repellent activity, which can be used as an active mosquito-repellent component to develop ethanol-free toilet water.
Objective To investigate the resistance of Culex pipiens quinquefasciatus to chemical insecticides commonly used in heavy disaster areas of the 5·12 Wenchuan Earthquake, Sichuan province, China, and to provide a reference for more scientific and rational selection and use of public health insecticides. Methods Mosquito larvae were collected from heavy disaster areas of the 5·12 Wenchuan Earthquake in Sichuan (experiment group) and non-heavy-disaster area in the urban district of Chengdu (control group). Additionally, standard susceptible strain was obtained from the insectaria of Sichuan Center for Disease Control and Prevention (control group). The dipping method was used to test the resistance of mosquito larvae to insecticides. Data were statistically analyzed using SPSS 17.0 to determine the median lethal concentration (LC50) and resistance grades. Results Compared with the control larvae, the experimental larvae showed significantly high resistance to beta-cypermethrin, with resistance ratios (RRs) of 2925.00 in Beichuan county, 1250.00 in Dujiangyan city, 2375.00 in Qingchuan county, and 1075.00 in Wenchuan county. To deltamethrin, the larvae in Beichuan and Dujiangyan showed high resistance (RR 90.59 vs. 71.77), while those in Qingchuan and Wenchuan showed moderate resistance (RR 14.12 vs. 21.18). All of the experimental larvae showed low resistance to dichlorvos (RRs 9.85, 5.29, 5.90, and 7.05). To Bassa, the experimental larvae showed reduced susceptibility in Beichuan, Dujiangyan, Wenchuan, and Qingchuan (RRs 3.90, 3.12, 3.83 and 1.57). Conclusion Culex pipiens quinquefasciatus larvae developed significantly high resistance to beta-cypermethrin and deltamethrin in heavy disaster areas of the 5·12 Wenchuan Earthquake. According to the usage of insecticides after earthquake, the high insecticide resistance of Cx. pipiens quinquefasciatus was relevant to massive uses of pyrethroid and organophosphorus insecticides for control of harmful insects.
Objective To study the species distribution and taxonomy of Culicoides (Fastus) in China. Methods Midges were captured using bed nets, light traps, and insect nets. Results A total of 12 species of Culicoides (Fastus) were recorded in China, including Culicoides (Fastus) mingshanensis sp. nov. The distribution of the 12 known species in China and the measurements of their major differential characteristics were described to compile an index list. Conclusion This study provides a reference for investigating the species distribution and taxonomy of Culicoides (Fastus) in China. C. mingshanensis sp. nov. has similar wing spots as C. festivipennis Kieffer, 1914, but the latter is distinctly different in the sensilla coeloconica of antenna situated on segments 3-15 and the third segment of palpus with sensory pit. The type specimen of the new species is deposited at the Shenyang Military Command Centre for Disease Control and Prevention (Shenyang 110034, China).
Objective To examine the effect of JWX-V thermal fogging insecticide against mosquitoes, flies, and cockroaches. Methods The insecticide was diluted to prepare 1% oil formulation and applied by aerosol spraying at doses of 1, 2, 3, and 4 ml/m3 in the laboratory simulation field. After 30, 60, 90, and 120 min of treatment, the knockdown and mortality of the three kinds of insects were examined. For field test, 3 ml/m3 oil formulation was applied by aerosol spraying for 60 min, and the mortality of the insects was then measured. Results In the laboratory test, the effect of the insecticide against the insects was proportional to the dose of drug and the duration of action. Under the action of 3 ml/m3 insecticide applied by aerosol spraying for 60 min, the 60 min knockdown rates of the three kinds of insects were all >95% and their 24 h mortality rates were 100%. In the field test with 3 ml/m3 insecticide applied by aerosol spraying for 60 min, the average 60 min mortality rates of mosquitoes and flies were 100% and 96.07% respectively, and the average 24 h mortality rate of cockroaches was 95.06%. Conclusion JWX-V thermal fogging insecticide has a good fumigant effect lethal to mosquitoes, flies, and cockroaches.
Objective To investigate the species, geographic distribution, and seasonalality of ticks in Henan province, China. Methods The specimens of free ticks and ectoparasitic ticks were collected with white cloth from grassland and picked from animals'body surfaces, respectively, throughout Henan province from 2011 to 2012. Results Eight species of ticks belonging to 6 genera and 2 families were found in the province. These ticks were Haemaphysalis longicornis, H. phasiana, H. flava, Rhipicephalus microplus, Dermacentor sinicus, Ixodes sinensis, Hyalomma detritum, and Argas reflexus. H. longicornis was distributed throughout the whole province and was the dominant species of ticks in Henan. It was found first in March or April, achieved the highest density in July or August, and became dormant after October. After winter, it reappeared in March or April of the next year. Conclusion There are relatively abundant species of ticks in Henan and they are widely distributed in the province. The activity peak of H. longicornis is in summer and autumn.
Objective To investigate the trends of Culex tritaeniorhynchus population dynamics in Liaoning province and to confirm that whether they carry Japanese encephalitis(JE)or not, which can support a scientific basis for establishing the strategy of prevention and control of Japanese encephalitis virus. Methods Culex tritaeniorhynchus, captureusing mosquito-lured lamp in 14 cities of Liaoning province during 2006-2013, were used to investigate the population composition and distribution and seasonality. Results Populations of Cx. tritaeniorhynchus in Liaoning province are mainly distributed in three cities, Dandong, Dalian and Panjin city, Dandong which has the highest distribution, the ratio of Culex is 78.43%, and the highest density is up to 780.20 Culex/(equipment·h) in 2007. In addition, Cx. tritaeniorhynchus were captured in Dalian, Panjin, Yingkou, Huludao and Jinzhou cities in different months. The highest density of Culex is appeared in September.Conclusion Culex mainly distributed in paddy growing areas of coastal cities in Liaoning province, including Dandong, Dalian, Panjin and Huludao;the most serious areas is Dandong city with the highest density and highest viral infection. In Lioaoning provience, there was a coincidence of early populations, high density and high JE infection. This phenomenon proves there is a relationship of Culex population trends and morbidity of JE, therefore, investigating the incidence of JE and the trends of Culex could not be ignored.
Objective To investigate the species and ecological differences of mite breeding in wheat bran stored in different ways. Methods Twenty-five wheat bran samples stored in different ways (bulk, package, and bucket) were collected from northern Anhui province, China. Mites breeding in the samples were isolated, identified, and counted. The following ecological indices were analyzed: breeding density, richness index, diversity index, and evenness index. Differences in the rate of mite breeding between the three storage methods were examined using 2 test. Results Eight species of mites were identified from 75 wheat bran samples, mainly including Caloglyphus berlesei (40.7% ) and Tyrophagus putrescentiae (33.3%). The breeding densities of mites in bulk, package, and bucket storage were 0.50, 0.25, and 0.30 mite/g, respectively. The corresponding values of richness index were 1.59, 1.18, and 0.94, respectively;the values of diversity index were 1.536, 1.222, and 1.167, respectively;the values of evenness index were 0.739, 0.759, and 0.725, respectively. The rates of mite breeding in bulk, package, and bucket storage were 48.0%, 24.0%, and 16.0%, respectively, with significant differences between the three storage methods ( χ2=6.047, P<0.05). Conclusion Mite breeding exists in wheat bran storage in northern Anhui province, where the rate of mite breeding is affected by the way of storage.
Objective To investigate pathological changes in the major solid viscera of guinea pigs infected with the plague bacillus Yersinia pestis. Methods Adult guinea pigs were infected with a virulent Y. pestis strain (25 cfu/ml) through the groin subcutaneously. After infection, tissue specimens were immediately taken from dead animals, and the surviving ones were executed 14 d later. Specimens of solid viscera, including the liver, spleen, lung, kidney, and heart, were used for isolation of Y. pestis, and section specimens were prepared to observe associated pathological changes. Results Yersinia pestis was isolated from the liver, spleen, lung, kidney, and heart of the experimental animals after infection. Tissue autopsy revealed significant pathological changes in all solid viscera, and microscopic examination showed obvious pathological changes in the major organs other than the heart. There were acute inflammatory changes such as inflammatory cell increase, hyperemia, hemorrhage, and partial necrosis. Conclusion Virulent Y. pestis can cause acute inflammation in guinea pigs and result in significant pathological changes in solid viscera of the animals, including the liver, spleen, lung, kidney, and heart.
Objective To analyze the epidemic situation of human brucellosis in Xinjiang Uygur Autonomous Region (Xinjiang), China, in 2013, and to provide a scientific reference for timely and effective implementation of relevant prevention and control measures. Methods According to the Implementation Plan for Monitoring of Human Brucellosis in Xinjiang, the epidemic situation was monitored in 4 project counties (cities and districts) and high-risk populations were screened out in 12 counties (cities and districts). A descriptive analysis was performed on the cumulative incidence of brucellosis reported in 2013 in Xinjiang. Results The 2013 epidemiological survey of brucellosis in Xinjiang involved 15 809 individuals in 16 project counties (cities and districts). Serological detection was performed on 10 553 samples, of which 1258 samples produced positive results (serum test positive rate 11.92%). There were 1185 patients with brucellosis (prevalence rate 7.50%), including 1136 new cases (incidence rate 5.16/100 000). Conclusion The serum test positive rate, prevalence rate, and incidence rate of brucellosis in Xinjiang were higher in 2013 than in 2012. In 2013, the cumulative incidence of brucellosis reported in Xinjiang was 3930 cases, which increased by 74.59% compared with that in 2012 (2251 cases). In view of the severe epidemic situation, Xinjiang needs to strengthen the monitoring of brucellosis epidemic situation and pay close attention to the epidemic dynamics.
Objective To analyze the epidemiological characteristics of hemorrhagic fever with renal syndrome (HFRS) and to assess its periodic prevention and control effects in Baoji, Shaanxi province, from 2005 to 2013, and to provide reference data for further developing prevention strategies. Methods An epidemiological analysis was performed on HFRS patients throughout the city from January 1, 2005 to December 31, 2013. The cumulative vaccination rate for HFRS was calculated. Results There were 2233 cases of HFRS reported in Baoji during 2005-2013, including 15 deaths. The average annual reported incidence of HFRS was 4.22/100 000, and 2012 was identified as a high-incidence year. Among the HFRS patients, the male-to-female ratio was 3.02:1, and most were 40-59-year-old peasants. Peak season lasted from October to January in the next year, and a small prevalence peak occurred in the summer harvest season. The age composition of HFRS onset shifted towards an older age, with an increasing proportion of those older than 60 years. The density of rodents at the monitoring points fluctuated between 0.24% and 15.17%. The cumulative vaccination rate with bivalent HFRS vaccine in the whole city was 82.49%. Conclusion Baoji has achieved significant effects in prevention and control of HFRS. However, the increasing proportion of HFRS patients towards an older age prompts a new challenge for prevention and control of this disease in the city.
Mosquito density is of great importance for preventing mosquito-borne diseases. Meteorological factors that influence the density of mosquitoes include temperature, rainfall, and humidity. This article reviews the progress in the impacts of climate change on mosquito populations, the relationship between meteorological factors and mosquito density, and the establishment of mosquito density predictive models using meteorological factors. Most current studies consider the association between single meteorological factors and mosquito density over the same period. But also some studies discuss the relationship between the time series of meteorological factors and mosquito density data. Moreover, there are some studies that consider the effects of meteorological factors and other factors affecting the density of mosquitoes. The present paper briefly describes the current problems and future directions in this research field.
German cockroach, Blattella germanica, a globally distributed sanitary pest, has become a big threat to human health. The commonly used pesticides against B. germanica are chemicals pesticides. However, the fact that B. germanica has developed resistance to such chemical pesticides turns our eyes to biopesticides. Entomogenous fungi are just an important type of such biopesticides. The anti-B. germanica activity of entomogenous fungi has already been studied. However, due to the existence of antibacterial peptides and endosymbionts, B. germanica shows great immunity to entomogenous fungi. In this paper, we review research advances in the species, propagation, infection, and pathogenic mechanism of entomogenous fungi for controlling B. germanica and discuss its future direction, with the purpose of providing a scientific basis for sustainable management of B. germanica.
Malaria remains one of the infectious diseases endangering human health. With the development of vaccines and adjuvants, the study and application of malaria vaccines faces enormous opportunities. This review summarizes advances in the study of malaria vaccines and discusses the current status of candidate malaria vaccines in terms of the problems faced, safety, antigen immunogenicity, and so on, to provide a reference for the study on optimization of malaria vaccines.
