Epidemiological Investigation and Genome Analysis of Duck Circovirus in Southern China

Duck circovirus （DuCV）, a potential immunosuppressive virus, was investigated in Southern China from March 2006 to December 2009 by using a polymerase chain reaction （PCR） based method. In this study, a total of 138 sick or dead duck samples from 18 different farms were examined with an average DuCV infection rate of-35%. It was found that ducks between the ages of 40~60 days were more susceptible to DuCV. There was no evidence showing that the DuCV virus was capable of vertical transmission. Farms with positive PCR results exhibited no regularly apparent clinical abnormalities such as feathering disorders, growth retardation or lower-than-average weight. The complete genomes of 91 strains from Fujian Province and 1 from Zhejiang Province were sequenced and analyzed. The 10 DuCV genomes, comlbared with others genomes downloaded from GenBank, ranged in size from 1988 to 1996 base pairs, with sequence identities ranging from 83.2% to 99.8%. Phylogenetic analysis based on genome sequences demonstrated that DuCVs can be divided into two distinct genetic genotypes, Group I （the Euro-USA lineage） and Group II（the Taiwan lineage）, with approximately 10.0% genetic difference between the two types. Molecular epidemiological data suggest there is no obvious difference among DuCV strains isolated from different geographic locations or different species, including Duck, Muscovy duck, Mule duck, Cheery duck, Mulard duck and Pekin duck.

Occupational Carbon Monoxide Poisoning Associated with Diesel Motor Operation in an Air-raid Shelter in June 2015, Jinan City, China-An Epidemiological Investigation

Carbon monoxide （CO） is an odorless, colorless gas produced by incomplete combustion of carbonbased compounds. Exposure to CO can cause various adverse health effects ranging from headache and fatigue to coma and death. Thousands of illnesses and deaths have been documented through CO poisoning surveillance systems and accident investigations each year.

Combination Use of PFGE and Drug-resistant Analysis in the Epidemiological Investigation of Listeria Monocytogenes

Listeria monocytogenes is the pathogen of listeriosis and it causes severe infections like septicemia, encephalitis, and meningitis, especially in immunocompromised individuals, newborns, and pregnant women. Its wide distribution in the environment and ability to survive or even grow under adverse conditions has made L. monocytogenes an important public health concern and in food industry.

Epidemiological investigation of Helicobacter pylori infection in elderly people in Beijing

BACKGROUND The Helicobacter pylori(H.pylori)infection rate in China is approximately 50%.H.pylori is a pathogenic factor of peptic ulcer and chronic gastritis.In addition,H.pylori infection may also be associated with a variety of cardiovascular diseases in elderly people,such as arteriosclerosis,coronary heart disease,and cerebral infarction,having deleterious effect on their health.With the aging of the population,the disease characteristics of the elderly population have been increasingly valued by the whole society.We conducted an epidemiological survey of H.pylori infection among elderly people in Beijing to provide a basis for health management of H.pylori infection.AIM To understand the epidemiological characteristics of H.pylori infection in elderly people in Beijing.METHODS A total of 1090 elderly people aged more than 60 years from different parts of Beijing(urban and rural areas)were selected using the random cluster sampling method.Structured questionnaires were completed during home visits and the 13C-urea breath test was conducted for H.pylori detection.RESULTS The prevalence of H.pylori infection was 46.5%(507/1090).The infection rate in men was 51.8%,which was significantly higher than that in women(42.5%;P<0.05).The H.pylori infection rate in illiterate people was significantly higher than that in literate persons(53.5%vs 44.8%,P<0.05).The total infection rate of H.pylori gradually increased with age and the difference was statistically significant(P<0.01).The H.pylori infection rate in smokers was significantly higher than that in non-smokers and those who had quit smoking(P<0.05).CONCLUSION The prevalence of H.pylori infection among elderly people is 46.5%and the infection rate gradually increases with age.Sex,education level,age,and smoking were determined to be H.pylori infection risk factors.The relationship of H.pylori infection with region,occupation,drinking,and diet structure needs to be further studied.

Studies on rickettsia-like organism (RLO) disease of tropical marine pearl oyster-Epidemiological investigation of RLO disease in juvenile populations of maricultured Pinctada maxima

The death which occurred in juvenile population was a severe problem in the course ofPinctada maxima artificial culture. With the methods of field investigation, histological study and statistic analyses, the epidemiological study was carried out on the disease and death in juvenile populations of Pinctada maxima in the Xinying Pearl Oyster Mariculture Farm of Lingao County (for the A, B and C batches of cultured juveniles hanged in the sea) and the Xincun Pearl Oyster Mariculture Farm of Lingshui County (for the D batch of cultured juvenile hanged in the pond), Hainan Province from November 1993 to April 1995.The results show that the deaths which occurred in juvenile populations of Pinctada maxima presented an outbreak pattern. The peak of mortality rates, in general, occurred in 4-to 6-month old pearl oyster juveniles, and the mortality rates gradully declined with the extention of pearl oyster age after cul-turing 8 months. The correlation between the mortality rates of juvenile populations and mean body lengths of juvenile populations show that the mortality rate become higher under 4 cm of mean body lengths of juvenile population and become obvious declined over 5 cm of mean body lengths. The peak of mortality rate occurred in 1-3 cm of mean body lengths. The results of histological observation showed that rickettsia-like organism inclusions were common, histological widespread infective agent among every batches (A, B, C and D) of cultured juvenile populations. The mean severity indices (SI) of rickettsia-like organism (RLO) infection were positively correlated with mortality rates of juvenile populations. After or within every peaks of RLO infection were all accompanied with the peaks of mortality rates of host populations and the mortality rates declined with decreased RLO infection. So the evidences of histological observation and epidemiology in this study indicated that rickettsia-like organism (RLO) may be as an important pathogenic organism of disease and death of cultured Pinctada maxima. In addition, a few ciliates were discovered only in part of batch A of cultured juvenile population. The mortality rates in juvenile populations were not correlated with the weekly mean temperature and salinity of sea water.

Studies on rickettsia-like organism (RLO)disease of tropical marine pearl oyster——Epidemiological investigation of RLO disease in larvae populations of maricultured Pinctada maxima

The epidemiological investigations on the disease and death in mature eggs, embryonic de- velopmental periods and larvae populations [including oocytes, fertilized ovum, early embryonic phase larvae (6 h), D-shaped phase larvae (24 h), early umbo phase larvae, umbo phase larvae, post um- bo phase larvae and eyespot phase larvae] in the Luhuitou Pearl Oyster Mariculture Farm of Sanya City, Hainan Province in April 1995 showed that there were two peaks of mortality rates which occurred in early umbo phase or umbo phase and post umbo phase (Figs 3-5 and Table 1) respectively from pre- embryonic developmental periods to larvae phases. It indicated that the onset and death of Pinctada maxima larvae populations followed a pattem of outbreak. Between the prevalence, intensity of RLO infection and the mortality rates of larvae populations were of obvious positively correlations. Generally, every peak of RLO infection is always follwed by a peak of mortality rate of larvae hosts, and the mor- tality rates of larvae hosts declined with the decreased RLO infection (see Figs 3-5 ). Under the trans- mission electron microscopy (TEM), no rickettsia-like organisms were discovered in oocytes, fertilized ovum and early embryonic phase larvae (6 h). The RLO inclusions occurred first in the D-shaped phase larvae (24 h) under histological examination. Absences of RLO in transmission electron exami- nation of oocytes of RLO-infected adult females, ferilized ovum and early embryonic phase larvae (6 h) indicated that RLO may not be transmitted transovarially. But RLO for host infection may be trans- mitted by contact transmission since RLO inclusions were first identified regularly in D-shaped phase larvae (24 h), while these D-shaped phase larvae were still unable to take food during hatching 24 hours. In addition, the result of epidemiological investigation showed that no odservable death occurred in D-shaped larvae populations, but early obvious death occurred in larvae populations in the seventh day after fertilization, in a rate of about 21. 8%. It indicated that there was a incubation peried from RLO infection for host (D-shaped phase larvae) to host onset and death occurred clinically.

Epidemiological Investigation of Porcine Contagious Pleuropneumonia in Some Areas of Anhui Province

By indirect hemagglutination test, the prevalence of porcine contagious pleuropneumonia was investigated in part of pig farms in Anhui Province. The results showed that the total positive rate of this area was 16.6%, and it was higher in sows.

Investigation of the epidemiology,pathogenicity and immunogenicity of Bordetella bronchiseptica isolated from cats and dogs in China from 2021 to 2023

Bordetella bronchiseptica(Bb)is recognized as a leading cause of respiratory diseases in dogs and cats.However,epidemiological data on Bb in dogs and cats in China are still limited,and there is no commercially available vaccine.Live vaccines containing Bb that are widely used abroad are generally efective but can establish latency and potentially reactivate to cause illness in some immunodefcient vaccinated recipients,raising safety concerns.In this study,34 canine-derived and two feline-derived Bb strains were isolated from 1809 canine and 113 feline nasopharyngeal swab samples collected from eight provinces in China from 2021 to 2023.The PCR results showed that the percentage of positive Bb was 22.94%(441/1922),and more than 90%of the Bb isolates had four virulence factor-encoding genes(VFGs),namely,fhaB,prn,betA and dnt.All the isolated strains displayed a multidrug-resistant phenotype.The virulence of 10 Bb strains isolated from dogs with respiratory symptoms was tested in mice,and we found that eight isolates were highly virulent.Furthermore,the eight Bb isolates with high virulence were inactivated and intramuscularly injected into mice,and three Bb strains(WH1218,WH1203 and WH1224)with the best protective efcacy were selected.Dogs immunized with these three strains exhibited strong protection against challenge with the Bb feld strain WH1218.Ultimately,the WH1218 strain with the greatest protection in dogs was selected as the vaccine candidate.Dogs and cats that received a vaccine containing 109 CFU of the inactivated WH1218 strain showed complete protection against challenge with the Bb feld strain WH1218.This study revealed that Bb is an important pathogen that causes respiratory diseases in domestic dogs and cats in China,and all the isolates exhibited multidrug resistance.The present work contributes to the current understanding of the prevalence,antimicrobial resistance,and virulence genes of Bb in domestic dogs and cats.Additionally,our results suggest that the WH1218 strain is a promising candidate safe and efcacious inactivated Bb vaccine.

Outcome of Epidemiological Investigation of COVID-19 Outbreak in a South West State of Nigeria, March to August 2020

Background: On 3rd April 2020, an outbreak of Coronavirus disease-2019 (COVID-19) was confirmed in Ondo State, Southwest Nigeria. Field investigations were conducted by the State Ministry of Health (MoH) to identify and confirm additional cases. This paper provides the outcome of the epidemiological investigation of the outbreak to further guide outbreak response activities. Methods: Field epidemiology methods coordinated by the State Public Health Emergency Operations Center (PHEOC) were used in the outbreak investigation. Suspected cases were reported through the routine Integrated Disease Surveillance and Response (IDSR) network in the State. Also, active case search/finding to communities and health facilities using the operational case definitions was conducted. Furthermore, the state COVID-19 emergency call center was established with toll-free phone number provided to members of the public to call-in to report suspected persons with symptoms consistent with the COVID-19 operational case definition (signal). All cases reported were investigated with nasopharyngeal sample collected and confirmatory testing for COVID-19 done by real-time polymerase chain reaction (RT-PCR) in a national reference laboratory. Information of each case investigated was documented using the COVID-19 case investigation form and COVID-19 line-list which captured socio-demographic characteristics, history of exposure to COVID-19, presenting symptoms, travel history and sample collection details. Data were extracted from the case investigation form and line list and analyzed using SPSS version 20, with a p-value set at < 0.05. Results: A total of 4353 suspected cases were reported and investigated, of which 1316 cases were confirmed between March 19, 2020 and August 9, 2020. The mean age of the confirmed cases was 37.8 ± 14.8 years. The highest proportion of COVID-19 cases and deaths occurred in the age group 20 - 39 years (50.6%) and ≥60 years (13.5%), respectively. More males (52.4%) were affected than females (45.8%). There were 404 (30.7%) healthcare workers infection. About a quarter (325;24.7%) of the cases was symptomatic and presented with key symptoms such as cough (98/325;30.2%) and fever (74/325;22.8%) during the investigation. A case fatality rate (CFR) of 2.2% was recorded in 7 of the 17 Local Government Areas (LGAs) where confirmed cases were reported in the State. Most of the confirmed cases, 1169 (88.8%) reside in urban LGAs of the State. The epidemic curve shows a propagated pattern of transmission with the outbreak reaching its peak on July 2, 2020. Significantly, higher proportion of death was recorded in the age group ≥ 60 years (14;13.5%) and among males (26;3.6%) (p < 0.001). Conclusions: Our investigation found high transmission of COVID-19 infection among urban residents (LGAs) and health care workers with high mortality among males in older age group in the State. Hence, we recommend intensified risk communication and use of community structures to ensure compliance with public health COVID-19 preventive protocols including enforcing infection prevention and control compliance, particularly among high-risk groups.

Epidemiological Investigation and Analysis of Chlamydia in Yak and Tibetan Sheep in Qinghai Province

Epidemiological investigation of chlamydia in yak and Tibetan sheep were conducted in Haiyan and Guinan counties, and samples were collected for laboratory detection, to understand the incidence range and damage degree of chlamydia in yak and Tibetan sheep in Qinghai Province. The result will provide technical support for preparation of scientific prevention and control measures against Chlamydia in Qinghai Province.

A Theoretical Investigation of the SARS-CoV-2Model via Fractional Order Epidemiological Model

We propose a theoretical study investigating the spread of the novel coronavirus(COVID-19)reported inWuhan City of China in 2019.We develop a mathematical model based on the novel corona virus’s characteristics and then use fractional calculus to fractionalize it.Various fractional order epidemicmodels have been formulated and analyzed using a number of iterative and numerical approacheswhile the complications arise due to singular kernel.We use the well-known Caputo-Fabrizio operator for the purposes of fictionalization because this operator is based on the non-singular kernel.Moreover,to analyze the existence and uniqueness,we will use the well-known fixed point theory.We also prove that the considered model has positive and bounded solutions.We also draw some numerical simulations to verify the theoretical work via graphical representations.We believe that the proposed epidemic model will be helpful for health officials to take some positive steps to control contagious diseases.

Epidemiological investigation of military training injuries for sea trainingand parachuting training

Objective: To study epidemiological characteristics of the military training injuries (MTI) during parachuting training of the air force and sea training of the navy. Methods:The subjects of this study were 1382, including 971 navy soldiers (300 recruits and 671 soldiers) and 411 for force recruits. Navy: Each of injured soldiers was investigated by the trained battalion surgeon; Air force: When the parachuting training finished , two doctors in specific field screened and investigated them one by one. Results: The incidence of injury in for force recruits was 16.3% and in navy recruits was 18. 7%. The incidence of navy soldiers was 5.5%, which was significantly lower than that of navy recruits. There was a peak of incidence in the 2nd training month of navy recruits. The peak of incidence of navy soldiers was in 1st training month. The incidence of air force maintained at a high level except 2nd training month. The incidences of lower legs and ankles were higher than those of other sites in navy with percentage of 42.9% and 17.9% respectively. The incidences of ankles and lumbar region were higher than those of other sites in air force with percentage of 26.9% and 23.9% respectively. Incidence of acute traumatic injuries was highest during special course. Conclusion: The result showed the incidence of injury in sea and parachuting training varied. Different preventive measures should be adopted during special training.

Analysis of Epidemiological Investigations and Responses to Human Rabies Deaths in Côte d’Ivoire, 2021

Rabies is an infectious disease that almost always leads to death as soon as the first signs appear, and is still endemic in several regions, including Côte d’Ivoire. Epidemiological investigations are carried out and response measures implemented in the event of any death from human rabies. However, the quality of these investigations does not always allow the adoption of response measures. The aim of this work was to evaluate the reports of epidemiological investigations and response actions carried out during the occurrence of human rabies deaths from 2016 to 2018. This was a cross-sectional study that took place from April to September 2021 at the National Institute of Public Hygiene and focused on human rabies deaths notified from 206 to 2018. Of sixty-one (61) human rabies deaths recorded, sixty (60) were investigated, among which fifty-nine (59) deaths had been subject to response. Most deaths occurred in rural areas (75%), and the main vector was the dog (98%). Several shortcomings were noted: response actions were not carried out promptly;joint interventions bringing together human and animal health professionals were rare, there was little communication about rabies to communities (36%), and very little vaccination of the vector, the source of the disease (12%);an almost total absence of capacity-building for local players (7%);the health districts of Abobo-Ouest, Bondoukou, Divo and Fresco, which had regularly recorded human rabies deaths, had not benefited from dog vaccination, which is supposed to break the circulation of the virus. The persistence of rabies deaths in the health districts could probably be linked to these shortcomings. Faced with these realities, it is essential to strengthen the epidemiological investigation capacities of the players involved, in order to improve the quality of investigations and ensure an effective response.

Epidemiological and clinical features,treatment status,and economic burden of traumatic spinal cord injury in China:a hospital-based retrospective study

Traumatic spinal cord injury is potentially catastrophic and can lead to permanent disability or even death.China has the largest population of patients with traumatic spinal cord injury.Previous studies of traumatic spinal cord injury in China have mostly been regional in scope;national-level studies have been rare.To the best of our knowledge,no national-level study of treatment status and economic burden has been performed.This retrospective study aimed to examine the epidemiological and clinical features,treatment status,and economic burden of traumatic spinal cord injury in China at the national level.We included 13,465 traumatic spinal cord injury patients who were injured between January 2013 and December 2018 and treated in 30 hospitals in 11 provinces/municipalities representing all geographical divisions of China.Patient epidemiological and clinical features,treatment status,and total and daily costs were recorded.Trends in the percentage of traumatic spinal cord injuries among all hospitalized patients and among patients hospitalized in the orthopedic department and cost of care were assessed by annual percentage change using the Joinpoint Regression Program.The percentage of traumatic spinal cord injuries among all hospitalized patients and among patients hospitalized in the orthopedic department did not significantly change overall(annual percentage change,-0.5%and 2.1%,respectively).A total of 10,053(74.7%)patients underwent surgery.Only 2.8%of patients who underwent surgery did so within 24 hours of injury.A total of 2005(14.9%)patients were treated with high-dose(≥500 mg)methylprednisolone sodium succinate/methylprednisolone(MPSS/MP);615(4.6%)received it within 8 hours.The total cost for acute traumatic spinal cord injury decreased over the study period(-4.7%),while daily cost did not significantly change(1.0%increase).Our findings indicate that public health initiatives should aim at improving hospitals’ability to complete early surgery within 24 hours,which is associated with improved sensorimotor recovery,increasing the awareness rate of clinical guidelines related to high-dose MPSS/MP to reduce the use of the treatment with insufficient evidence.

Epidemiological Investigation on the Etiology of Glasser＇s Disease in China

Haemophilus parasuis（HPS） is one of the most important bacterial infectious diseases harming China＇s pig industry for the last few years.To understand the prevalence status of glasser＇s disease in China, the disease samples submitted by Shandong, Henan, Heilongjiang, Jiangxi, Liaon-ing, Guangdong, Shaanxi and Sichuan provinces were isolated and identified. The synovial fluid, lung, brain tissue, heart blood and nasal cavity ofsick pigs in 194 pig farms collected from 2006 to 2009 were detected, and 47 strains of HPS were eventually isolated, with the separation rate of24.2%. Serotypes of the isolates were identified through KRG （Kieletein-Rapp-Gabriedson） agar diffusion method. There were 13 strains of serotype4 （27.7%）, 10 strains of serotype 5 （21.3%）, 8 strains of serotype 12 （17%） and7 strains of serotype 13 （14.9%）, indicating the major serotypes ofHPS in China were serotype 4, serotype 5, serotype 12 and serotype 13.

Epidemiological Investigation of Avian Leukemia in Some Indigenous Chicken Breeds of China

[ Objective] The paper was to understand the natural infection status of avian leukemia in some indigenous chicken breeds of China. [ Method ] Using ELISA assay and virus isolation method, epidemiological investigation of ALV-AB and ALV-J avian leukemia of 10 indigenous chicken breeds were conducted. ALV dynamics were monitored in F2 generation of four chicken lines. ALV pollution of attenuated live vaccines used in raising process was also inspected through sampling method. [ Result] The positive rate of ALV-P27 antigen was 0 -62.1% ; the positive rate of ALV-AB antibody was 0 -25.0% ; the positive rate of ALV-J antibody was 0 - 59.0% ; the positive rate of virus isolation was 0 - 22.0%. The positive rate of ALV-P＇27 antigen in 1 -day-old chick mecunium of four lines was 6.0% - 67.0%. The positive rate of virus isolation in 6-week-old chickens was 2.0% - 34.3%. Two kinds of vaccines from two hatches pro- duced by a manufacturer were polluted by ALV. [ Conclusion] Most indigenous chickens were infected by ALV. There were great differences among different breeds of indigenous chicken, which might be related to ALV genetic resistance of different indigenous chickens. The ALV positive rates of F： chicks were slightly enhanced in some lines, which might be related to vaccine pollution.

Analysis of Epidemiological Investigations and Responses to Human Rabies Deaths in Côte d’Ivoire, 2021

Rabies is an infectious disease that almost always leads to death as soon as the first signs appear, and is still endemic in several regions, including Côte d’Ivoire. Epidemiological investigations are carried out and response measures implemented in the event of any death from human rabies. However, the quality of these investigations does not always allow the adoption of response measures. The aim of this work was to evaluate the reports of epidemiological investigations and response actions carried out during the occurrence of human rabies deaths from 2016 to 2018. This was a cross-sectional study that took place from April to September 2021 at the National Institute of Public Hygiene and focused on human rabies deaths notified from 206 to 2018. Of sixty-one (61) human rabies deaths recorded, sixty (60) were investigated, among which fifty-nine (59) deaths had been subject to response. Most deaths occurred in rural areas (75%), and the main vector was the dog (98%). Several shortcomings were noted: response actions were not carried out promptly;joint interventions bringing together human and animal health professionals were rare, there was little communication about rabies to communities (36%), and very little vaccination of the vector, the source of the disease (12%);an almost total absence of capacity-building for local players (7%);the health districts of Abobo-Ouest, Bondoukou, Divo and Fresco, which had regularly recorded human rabies deaths, had not benefited from dog vaccination, which is supposed to break the circulation of the virus. The persistence of rabies deaths in the health districts could probably be linked to these shortcomings. Faced with these realities, it is essential to strengthen the epidemiological investigation capacities of the players involved, in order to improve the quality of investigations and ensure an effective response.

Epidemiological Investigation of Brucellosis Spondylitis and Optimal Selection of Clinical Drug Compatibility, Treatment Course and Treatment Plan

Background: Brucellosis is a zoonotic endemic disease, the main source of infection is infected cattle, sheep, pigs and their products. In recent years, the global incidence of brucellosis spondylitis has increased year by year, and it has spread from pastoral areas to semi-agricultural and semi-pastoral areas, agricultural areas and cities. It has changed from a mainly occupational disease to a mainly food-borne disease, and it is also a zoonotic specific spinal infectious disease that WHO and governments around the world pay great attention to. Due to the low cure rate and high recurrence rate of traditional drug therapy regimen. Therefore, to carry out epidemiological investigation and Related research on clinical drug therapy of brucellosis spondylitis has practical significance for improving diagnosis rate, cure rate and reducing recurrence rate. Objective: To analyze the epidemiological characteristics of Brucellosis spondylitis and explore the choice of drugs and the best drug treatment plan, so as to provide scientific basis for improving the prevention and control of the disease and treatment effect. Methods: Clinical epidemiodogical materials were collected from 113 patients with brucellar spondylitis. All these patients were divided into 5 different groups according to 5 kinds of drugs adopted respectively, and then the patients were given different course of treatment. Results: In the 113 patients, brucellar spondylitis morbility of female patients were higher than that of male ones, and the morbility of Bashang were higher than that of Baxia. These patients were infected mainly through browsing and breeding beasts. Lumbars were the major focus of infection. It was very comnlon that two adjacent lumbars were involved in concurrently. L4 was the most common infection location and its demolishment was most serious. The curative effect of group treated with doxycycline was better than that of group treated without doxycycline. If the course of treatment Was increased, the curative effect Was not increased obviously. Conclusions: There are characteristic features in clinical epidemiology of brucell spondylitis. Doxycycline + Rifampicin + Sulfamethoxazole was used as the preferred antibiotic. Using antibiotics adequately and jointly by two courses of treatment for a long time is the most reasonable way to treat the disease and prevent the disease from recurrence.

Experimental investigation on coal pore-fracture variation and fractal characteristics synergistically affected by solvents for improving clean gas extraction

Chemical solvents instead of pure water being as hydraulic fracturing fluid could effectively increase permeability and improve clean methane extraction efficiency.However,pore-fracture variation features of lean coal synergistically affected by solvents have not been fully understood.Ultrasonic testing,nuclear magnetic resonance analysis,liquid phase mass spectrometry was adopted to comprehensively analyze pore-fracture change characteristics of lean coal treated by combined solvent(NMP and CS_(2)).Meanwhile,quantitative characterization of above changing properties was conducted using geometric fractal theory.Relationship model between permeability,fractal dimension and porosity were established.Results indicate that the end face fractures of coal are well developed after CS2and combined solvent treatments,of which,end face box-counting fractal dimensions range from 1.1227 to 1.4767.Maximum decreases in ultrasonic longitudinal wave velocity of coal affected by NMP,CS_(2)and combined solvent are 2.700%,20.521%,22.454%,respectively.Solvent treatments could lead to increasing amount of both mesopores and macropores.Decrease ratio of fractal dimension Dsis 0.259%–2.159%,while permeability increases ratio of NMR ranges from 0.1904 to 6.4486.Meanwhile,combined solvent could dissolve coal polar and non-polar small molecules and expand flow space.Results could provide reference for solvent selection and parameter optimization of permeability-enhancement technology.

Epidemiological survey of cystic echinococcosis in southwest China:From the Qinghai-Tibet plateau to the area of Yunnan

BACKGROUND Echinococcosis is prevalent in 9 provinces in Western and Northern China.An epidemiological survey of echinococcosis in 2012 and 2016 showed cases of echinococcosis in Yunnan Province.AIM To understand the spatial distribution and epidemiological characteristics of echinococcosis in Yunnan for the prevention and control of echinococcosis and to reduce the risk of infection in Yunnan Province.METHODS Based on the China Information System for Disease Control and Prevention(CISDCP),echinococcosis cases reported from 36 hospitals and 34 Centers for Disease Control were investigated and epidemiologically analyzed from 2021 to 2022.The exclusion criteria included suspected cases,same case only counted once and cases not from Yunnan.A total of 705 cases were investigated,of which 397 cases were suitable for statistical analysis.In these 397 cases,epidemiological investigation was tracked in 187 cases.All data were inputted using double entry in the Excel database,with error correction by double-entry comparison.The data on echinococcosis cases in Yunnan Province were analyzed by ArcGIS 10.1 software to generate a density map of echinococcosis distribution.All statistical analyses were conducted using SPSS 17.0,including the chi-square test,linear regression test and logistic univariate and multivariate regression analyses.RESULTS A total of 397 cases were found in 89 counties in Yunnan Province.The number of cases in the top three prefectures were Dali(38.1%),Diqing(10.1%),and Kunming(8.3%),and the top five counties were Jianchuan(9.1%),Shangri La(8.3%),Eryuan(7.6%),Heqing(6.9%),and Dali Districts(5.0%).There were significant differences between the different areas.The case reporting rate by CISDCP(33.8%)was low;the first case was reported by CISDCP in 2002,and the highest number of cases was 50(2017).Confirmed and clinical cases accounted for 62.5%and 37.5%,respectively.However,90.9%of the cases of hydatid disease were reported by the hospital system,and only 9.1%of the cases of hydatid disease were found in the community through active screening.The difference between the two methods of case detection was statistically significant.Most of the cases of echinococcosis were found in farmers/herdsmen(75.1%)and students(9.1%).In addition,Han(43.6%)and Bai(26.2%)had a higher incidence of infection than other nationalities,and the liver(87.7%)and lung(6.8%)were the most common sites of cyst formation.Among the analyzed cases,187 were epidemiologically analyzed and the clinical symptoms were not obvious in the early stage in 47.1%of cases.The results of logistic regression analysis showed that the age group,education level,presence of dogs in the family(either previously or currently),and handwashing(occasionally or not)were factors related to echinococcosis infection.55.6%of cases were in endemic areas,and 44.4%of cases were in non-endemic areas.Among 83 cases in non-endemic areas,only 4 cases had been to endemic areas and had a history of living,working,travelling,or hunting in echinococcosis epidemic areas.CONCLUSION Cases of echinococcosis were reported throughout the entire Yunnan province,with the majority distributed in Western Yunnan,suggesting that echinococcosis control should be strengthened in this area.We suggest that an epidemiological investigation should be carried out in the future,based on the clues from newly discovered cases in hospitals or from the CISDCP.The newly discovered cases in the hospital provided clues to comprehensively determine the location of cases and where epidemic spot investigation should be conducted.