Seroepidemiological investigation of lyme disease and human granulocytic anaplasmosis among people living in forest areas of eight provinces in China.

OBJECTIVE: Lyme disease and Human granulocytic anaplasmosis are tick-borne diseases caused by Borrelia burgdorferi and Anaplasma phagocytophilum respectively. We have investigated infection and co-infection of the two diseases in the population of forest areas of eight provinces in China by measuring seroprevalence of antibodies against B. burgdorferi and A. phagocytophilum. METHODS: Forest areas in 8 provinces were chosen for investigation using whole sampling and questionnaire survey methods. 3 669 serum samples from people in the forest areas were tested for the presence of antibodies by indirect immunofluorescent assay (IFA). RESULTS: Seroprevalence against B. burgdorferi was 3% to 15% and against A. phagocytophilum was 2% to 18% in the study sites in the 8 provinces in China. We also found co-infection of B. burgdorferi and A. phagocytophilum in 7 of the 8 provinces (the exception being the Miyun area in Beijing). The seroprevalence for both B. burgdorferi and A. phagocytophilum was significantly higher among people exposed to ticks than among people who were not exposed to ticks. CONCLUSION: We conclude that both pathogens are endemic in the forest areas in the eight provinces, but the prevalence of B. burgdorferi and A. phagocytophilum differs between the provinces.

[Analysis of pathogen spectrum of Encephalitis/Meningitis in northwestern area of China].

OBJECTIVE: To learn the characteristics of pathogen spectrum of Encephalitis /Meningitis in northwestern area of China. METHODS: Between January 1st 2009 and March 31st 2011, a total of 569 patients with clinical symptoms of Encephalitis/Meningitis were selected from the hospitals in Gansu, Qinghai,Inner Mongolia and Xinjiang province. 1514 samples of specimen were collected from the 515 patients, to detect the IgM of Japanese encephalitis virus (JEV), enterovirus (EV, including Coxsackie virus, ECHO virus and enterovirus 71), Mumps virus, Herpes simplex virus (HSV) in blood and cerebrospinal fluid. Meanwhile, Neisseria meningitis (Nm), Haemophilus influenzae Type B (Hib), Staphylococcus, Streptococcus pneumonia, Streptococcus Suis, E. Coli and Cryptococci were also identified. The detection results were analyzed by different region, time and age range. RESULTS: Pathogenic bacteria were identified in the specimen from 16 patients, with the rate at 3.65%, of which the dominant ones were Streptococcus pneumonia (7 patients, 43.75%). Virus were identified in the specimen from 132 patients, with the rate at 27.05%, of which the dominant types were EV and HSV, accounting for 33.33% (44 cases) and 31.82% (42 cases) respectively. The detection rate of virus showed a significant seasonal trend, with the peak appearing between June and November each year. The peak of EV detection was between July and September, with 24 cases detected out; the peak of HSV was between June and August (11 cases detected out); mumps virus was mainly found between July and December (25 cases). There was no significant time-distribution found in the detection of bacteria. The EV and HSV were mainly distributed in Gansu and Qinghai province (70 cases) ;most of mumps virus were found in Gansu province (24 cases);and JEV were only found in Gansu province (20 cases). The viral pathogen spectrum was identified in all ages, and the EV and mumps virus were mainly found in children aged 0-14 years old (42 and 17 cases respectively) ; JEV were identified in people over 15 years old, with 13 detected out of the 20 patients. CONCLUSION: The main pathogen of acute encephalitis and meningitis in northwestern area of China was virus, and the main pathogens of encephalitis and meningitis in children under 15 years were Herpes simplex virus and Mumps virus.

[Analysis on epidemiology and the main clinical symptoms of viral encephalitis in Gansu, 2009-2011].

OBJECTIVE: To understand the epidemiological characteristics and the main clinical symptoms of viral encephalitis in Gansu. METHODS: A total of 322 viral encephalitis patients were recruited from province sentinel hospitals in Gansu province from 2009 to 2011, and their basic information were collected as well as their serum samples and cerebrospinal fluid samples. 296 out of the 322 cases were qualified for our study. Based on the patients' epidemiological characteristics and clinical features, we determined the detection of the virus types (at least one kind of virus detection was carried out for each case). ELISA was applied to test the IgM antibody of Japanese encephalitis (JE) virus (JEV), enterovirus (EV: including Coxsackie virus, echovirus, enterovirus 71), mumps virus and herpes simplex virus (HSV) in cerebrospinal fluid and serum specimen. The difference of positive detected rate between types of virus, among patients from different regions, time, or at different ages, as well as the different clinical symptoms between JE patients and other viral encephalitis patients, were analyzed and compared. RESULTS: The positive detected rate of virus in the 296 patients was 27.03% (80/296); the positive rate of JEV, EV, mumps virus, HSV detected was separately 7.53% (22/292), 8.75% (23/263), 13.84% (22/159) and 15.09% (40/265), and the difference was statistically significant (χ(2) = 10.849, P < 0.05). 90.91% (20/22) of the JEV positive cases were distributed in Tianshui, Longnan and Pingliang, and 95.45% (21/22) patients were infected from July to September. All the 23 EV detected positive patients were infected from April to December, while the ages of patients ranged from 1 to 44 years old. Mumps virus, HSV testing positive cases had onset every month. Logistic regression analysis showed that the patients who had the symptoms as disturbance of consciousness (OR = 15.487, 95%CI: 2.266 - 105.852), somnolence (OR = 11.659, 95%CI: 1.783 - 76.242), convulsions (OR = 11.062, 95%CI: 1.687 - 72.530) were more likely to infect JEV. CONCLUSION: HSV was the principal pathogen of viral encephalitis in Gansu. An obvious central tendency in the regional and time distribution was found in JEV infection; and the clinical symptoms of JE patients were more severe.

[Epidemiological features and pathogenic characteristics of hand, foot and mouth disease in Gansu Province, China during 2008-2012].

This study aims to analyze the epidemiological features and pathogenic characteristics of hand, foot and mouth disease (HFMD) in Gansu Province, China and to provide a basis for the development of effective prevention and control measures. The descriptive epidemiological analysis was used to analyse the data of HFMD cases in Gansu. The specimens collected from hospitals were subjected to RT-PCR or real-time PCR to detect human enterovirus (HEV) nucleic acid, and HEV strains were isolated using human rhabdomyosarcoma cells and human laryngeal carcinoma cells. The complete VP1-encoding region of several identified enterovirus A71 (EV71) and coxsackievirus A16 (CVA16) was subjected to full-length amplification by RT-PCR and then to sequencing and analysis. A total of 52 550 HFMD cases were reported in Gansu from 2008 to 2012, including 205 severe cases and 27 deaths. The incidence rates in the whole province from 2008 to 2012 were 22.42/10(5), 49.29/10(5), 47.20/10(5), 27.27/10(5), and 55.84/10(5), respectively. There were cases in all the 14 cities or prefectures in Gansu, and Lanzhou had the largest number of cases (16 001 cases), accounting for 30.45% of all cases in the province. HFMD cases were mostly reported during May to July, accounting for 51.69% of all cases throughout the year. The male-to-female ratio was 1.69:1. Of all the cases, 87.59% were under the age of five. Of the 5 416 cases for laboratory tests, 3 322 (61.34%) were positive for HEV nucleic acid, including EV71 (46.96%), CVA16 (41.57%), and other HEVs (11.47%). Among the 186 severe cases, 114 (61.29%) were positive for HEV nucleic acid, and 82.46% of the positive cases for EV71. All the 25 dead cases were infected with EV71. A total of 402 strains were isolated from 3 111 specimens collected from hospitals (2 123 throat swab specimens, 705 stool specimens, and 705 herpes specimens), including EV71 (70.15%), CVA16 (27.11), other coxsackievirus A (3.98%), coxsackievirus B (2.49%), echovirus (1.74%), and adenovirus (1.99%). The genotyping of VP1- encoding region showed that all the 194 EV71 strains isolated during 2008-2012 belonged to the C4a evolutionary branch of C4 subtype; among the 45 CVA16 strains, 12 belonged to the Bla evolutionary branch of B1 subtype and 33 to the B1b evolutionary branch, and B1b became the predominant subtype in 2012. In conclusion, in Gansu Province, HFMD occurs mostly in children under the age of five; EV71 and CVA16 are the main pathogens of this disease, and the two are predominant alternately from 2008 to 2012; the severe and dead cases of HFMD are closely related to infection with EV71; the types of pathogens varied across different regions in the same year during 2008-2012.

[Genetic characterization of human parainfluenza virus 3 circulating in Gansu and Shaanxi Provinces from 2009 to 2011].

To investigate the genetic characterization of Human parainfluenza virus-3 (HPIV-3) circulating in Gansu and Shaanxi Provinces of China, 719 throat swabs were collected from pediatric patients with acute respiratory infections from 2009-2011. Multiplex RT-PCR was used to screen common respiratory viral pathogens. For HPIV-3-positive specimens, nested RT-PCR was used to amplify the HN gene of HPIV-3. The nucleotides of Hemagglutinin-neuraminidase(HN)gene of 13 HPIV-3 positive strains identified in Gansu and Shaanxi Provinces were successfully sequenced and compared with those downloaded from GenBank. The phylogenetic analysis based on the nucleotides sequence of HN gene showed that 13 HPIV-3 strains belonged to sub-cluster C3 with little sequence variation (overall nucleotide divergence of 0.2%-2.3% and amino acid divergence at 0-1.1%). Compared with the complete gene of HPIV-3 strains from U.S.A., Canada, and Australia, the biggest divergence of the nucleotide and amino acid lovels was 6.0% and 3.4%, respectively. The nucleotide divergence between shaanxi09-2 and shaanxi10-H0091 was 0.9%, while the nucleotide divergence between shaanxi10-H005 and gansull-62110372 was 0.5%, between shaanxi09-2 and BJ/291/09 was 0.6%. However, there was no amino acid divergence among them. It is likely that HPIV-3 virus had been transmitting in Gansu and Shaanxi Provinces for several years. Human parainfluenza virus-3 (HPIV-3) circulated in Gansu and Shaanxi Provinces from 2009 to 2011 belonged to sub-cluster C3.

[Characterization of human rhinovirus in children with acute respiratory infections in Gansu Province during 2011].

To study the epidemic characteristics of human rhinovirus (HRV) in children with acute respiratory infections in Gansu Province. 286 throat swabs were collected from children with acute respiratory in fections in Gansu Province during 2011. Multiplex reverse transcription-PCR (multiplex RT-PCR) assay was used to screen those specimens for detection of common respiratory tract pathogens. For HRV-positive samples, nested reverse transcription polymerase chain reaction (nested RT-PCR) was performed to amplify VP1 and VP4/VP2 gene fragments of HRV. The VP4/VP2 and VP1 regions of HRV-positive samples were sequenced and performed genotype analysis. Of 286 specimens fested, 27 were positive for HRV by multiplex RT-PCR and nested RT-PCR, of which 16 children were made (16/185), 8.64%) and 11 female (11/101,10.89%). The positive rate was 9.44% (27/286). The mean age of HRV-positive children was 3 years in this study, children less than one year old had the highest proportion 44.4% (12/ 27, 44.4%). The highest HRV positive rate fell on May, 2011 (6/27, 22.2%). Common cold accounted for the highest proportion, 12.24% (12/98) followed by pneumonia, 8.50% (13/153). The remaining 2 cases were bronchitis. Sequence analysis showed HRV A was the predominant genotype in Gansu Province in 2011, accounting for 84.62% (22/26) of positive cases, followed by HRV C (11.54%, 3/26) and only one HRV B was detected (3.85%, 1/26). HRV could be detected throughout the year in Gansu Province and primarily infected children under one year old. The group A was the epidemic genotype of HRV and move than one genotype existed in Gansu Province during 2011.

[Analysis of influenza type A(H1N1) antibody levels in different population in Gansu province].

OBJECTIVE: To investigate influenza type A(H1N1) antibody levels in 3 different population which included common people, people recovered from be infected with influenza A(H1N1) and people vaccinated influenza type A(H1N1) vaccine in Gansu province in 2009. METHODS: Hemagglutination Inhibition (HI) test, HI test is positive when HI-titer > or = 1:40. RESULTS: The influenza type A(H1N1) antibody-positive rate of urban population were 3.64% (11/302) and 10.45% (44/421) in Gansu province in August and later November respectively. The antibody-positive rate of people vaccinated after 30 days was 46.13% (131/284), GMT was 1:21.31. 10-15 days after infected by influenza type A(H1N1), HI antibody-positive rate was 87.04%, it rose to 96.40% after 15 days vaccination, and GMT was 1:139.4. CONCLUSION: In Gansu, Influenza A H1N1 outbroke firstly among students. Currently, all age groups were reported being infected with the influenza type A H1N1 virus. Only 6.65% of residents were given vaccination, antibody level of influenza type A H1N1 in people was low. Influenza type A(H1N1) virus will continue to spread in Gansu. Strengthening vaccination and improving treatment to serious cases were recommended strategies for influenza type A H1N1 control and prevention.

[Hepatitis viruses infection situation in human population of the Gansu province].

OBJECTIVE: To investigate the seroprevalence of hepatitis viruses in human population of Ganso province. METHODS: ELISA was used for detecting anti-HAY IgG, HBsAg/HBsAb, anti-HCV IgG and anti-HEV IgG of the serum samples. All sample were collected in four areas of KL, LT, HN and ZhL of Gansu province in 2008. RESULTS: 1977 samples were detected, The positive rates of anti-HAY, HBsAg/HBsAh, anti-HCV, and anti-HEY are 84.57% (1672/1977), 4.81% (95/1977) and 28.73% (568/1977), 0.46% (9/1977),and 13.10% (259/1977), respectively. The positive rate at different age group, for anti-HAY was 43.21% of c 9 years old, 80.23% of 10-19 years old, 93.02% of 20-29 years old, 95.55% of 30-39 years old, 95.60%-97.52% of 40-60 years old. For HBsAg/HBsAb were 2.09% or 29.27%, 3.02% or 21.81%, 6.20% or 36.43%, 5.93% or 31.16%, 6.43% or 3l.43%, 7.32% or 24.88%, 3.33% or 28.89% at the same age group, respectively, for anti-HCV, was 0.59% of 30-39 years old, 1.79% of 40-49 years old, 0.98% of 50-59 years old. For HEY-IgG was 3.48% of < or =9 years old, 6.05% of 10-19 years old, 8.53% of 20-29 years old, 19.29%-21.67% of 30- > or =60 years old. CONCLUSIONS: The inoculation againt HAY and HBY is enhanced in the youngster population. HBsAg carrier and UCY infection is decreasing. The HEY infection in the Hid people is lower than the Han nationality.

[Molecular characterization of Japanese encephalitis virus isolated from Gansu province in 2008].

OBJECTIVE: To sequence PrM and E gene of the Japanese encephalitis virus isolated from Gansu province in 2008 and analysis the genotype of new JEV isolates and the molecular characterization of E gene. METHODS: Computer software was used to analyze nucleic acid sequence and deduced amino acid sequence, and draw phylogenetic trees, including ClustalX2.09, MegAlign and Mega4. RESULTS: The six JEV strains were clustered in genotype I. 87.5%-87.9% identity in nucleotide sequence and 96.8%-97.2% identity in amino acid sequence were found in E gene when compared with the vaccine strain SA14-14-2. Eleven common amino acid differences were observed in E protein between new isolates and the vaccine strain. CONCLUSION: Genotype I JEVs were isolated from mosquitoes collected in Gansu province. The amino acid difference occurred in sites that were not the key ones affecting the antigenic of JEV.

[Analysis of influenza surveillance from 2000 to 2007 in Gansu province].

OBJECTIVE: To study the epidemical characteristics of influenza in Gansu province from 2000 to 2007, and to discuss the changes of the predominant strains of influenza virus. This study provide scientific basis for defending influenza effectively. METHODS: Influenza surveillance, collecting the pharyngeal swab specimens from influenza patients of national surveillance hospital and unsure influenza epidemic situations, inoculated on MDCK cell culture to obtain the influenza virus strains. RESULTS: 2001.10-2007.12, collecting the 6383 specimens, 943 influenza virus strains were isolated, positive rate was 14.77%, 218 strains were A1 (H1N1 ), 352 strains were A3 (H3N2), 312 strains were B subtype of Victoria and 61 strains were B subtype of Yamagata. There were totally 61 outbreak of influenza-like cases were observed in Gansu Province during the last 5 years, 44 cases were isolated influenza virus, of 38 cases were caused by B subtype of Victoria virus strains, 3 cases were caused by H3N2, 2 cases were caused by B subtype of Yamagata virus strains, 1 cases were caused by H1N1. CONCLUSION: Influenza is active in human population. Influenza type A virus is predominant in winter and type B virus resulted in the outbreak in school and kidsgarden from March to June in the last 3 years.

[Sero-epidemiological characteristics of antibody to SARS-associated coronavirus in Gansu Province].

OBJECTIVE: To study the levels of SARS-associated coronavirus IgG antibody of SARS patients, people who closely contacted SARS patients and normal subjects in Gansu province. METHODS: The levels of SARS-associated coronavirus IgG antibody were measured by ELISA. The material included acute and (or) recovery period sera of 9 SARS patients, sera from 1,109 doctors and nurses closely contacted with SARS patients, laboratory workers, personnel for disease control and prevention, persons who contacted SARS patients, and sera from 978 normal subjects. RESULTS: SARS coronavirus IgG antibody was detected positive in 6 of the 9 patients, it was still positive in the sera twelve months after recovery; 1 of the closely contacted persons and 3 normal subjects were found positive. CONCLUSION: The positive rate of SARS coronavirus IgG antibody of patients was consistent with the clinical diagnosis. The low positive rate of the persons who closely contacted SARS patients and normal subjects suggests that SARS probably had no subclinical infection.