Huang F.,National Institute of Parasitic Diseases |
Huang F.,Collaborating Center for Malaria |
Huang F.,Laboratory of Parasite and Vector Biology |
Zhou S.,National Institute of Parasitic Diseases |
And 9 more authors.
Background: Malaria has been endemic in Linzhi Prefecture in the Tibet Autonomous Region (TAR) over the past 20 years, especially in Motou County with a highest incidence in the country in recent years. Meteorological factors, such as rainfall, temperature and relative humidity in Motou County were unique compared to other areas in Tibet as well as other parts of China, thus the objective of this work was to analyse the temporal correlation between malaria incidence and meteorological factors in Motou County, in order to seek the particular interventions for malaria control. Methods. The meteorological and malaria data during 1986-2009 in Motuo County were studied to analyse the statistical relationship between meteorological data time series and malaria incidence data series. Temporal correlation between malaria incidence and meteorological factors were analyzed using several statistical methods. Spearman correlation analysis was conducted to examine the association between monthly malaria incidence and meteorological variables. Cross-correlation analysis of monthly malaria incidence series and monthly meteorological data time series revealed the time lag(s) of meteorological factors preceding malaria at which the series showed strongest correlation. Multiplicative seasonal auto-regressive integrated moving average (SARIMA) models were used in the cross-correlation analysis with pre-whitening which remove seasonality and auto-correlation of meteorological data series. Differenced data analysis which called inter-annual analysis was carried out to find underlying relationship between malaria data series and meteorological data series. Results: It has been revealed that meteorological variables, such as temperature, relative humidity and rainfall were the important environmental factors in the transmission of malaria. Spearman correlation analysis demonstrated relative humidity was greatest relative to malaria incidence and the correlation coefficient was 0.543(P < 0.01). Strong positive correlations were found for malaria incidence time series lagging one to three months behind rainfall (r > 0.4) and lagging zero to two months behind temperature and relative humidity (r > 0.5) by the cross-correlation. Correlations were weaker with pre-whitening than without. The cross-correlograms between malaria incidence and various meteorological variables were entirely different. It was fluctuated randomly for temperature but with trend for the other two factors, which showed positive correlated to malaria when lag was from 0 to 5 months and negative from 6 to 12 months. Besides, the inter-annual analysis showed strong correlation between differenced annual malaria incidence and differenced meteorological variables (annual average maximum temperature, annual average relative humidity and annual average rainfall). The correlations coefficients were -0.668 (P < 0.01), 0.451(P < 0.05) and 0.432(P < 0.05), respectively. Conclusion: Meteorological variables play important environmental roles in malaria transmission in Motou County. Relative humidity was the greatest influence factors, which affected the mosquito survival directly. The relationship between malaria incidence and rainfall was complex and it was not directly and linearly. The lags of temperature and relative humidity were similar and smaller than that of rainfall. Since the lags of meteorological variables affecting malaria transmission were short, it was difficult to do accurate long-term malaria incidence prediction using meteorological variables. © 2011 Huang et al; licensee BioMed Central Ltd. Source
Zhou S.S.,National Institute of Parasitic Diseases |
Zhou S.S.,Collaborating Center for Malaria |
Zhou S.S.,Laboratory of Parasite and Vector Biology |
Huang F.,National Institute of Parasitic Diseases |
And 10 more authors.
Background. Malaria still represents a significant public health problem in China, and the cases dramatically increased in the areas along the Huang-Huai River of central China after 2001. Considering spatial aggregation of malaria cases and specific vectors, the geographical, meteorological and vectorial factors were analysed to determine the key factors related to malaria re-emergence in these particular areas. Methods. The geographic information of 357 malaria cases and 603 water bodies in 113 villages were collected to analyse the relationship between the residence of malaria cases and water body. Spearman rank correlation, multiple regression, curve fitting and trend analysis were used to explain the relationship between the meteorological factors and malaria incidence. Entomological investigation was conducted in two sites to get the vectorial capacity and the basic reproductive rate to determine whether the effect of vector lead to malaria re-emergence. Results. The distances from household of cases to the nearest water-body was positive-skew distributed, the median was 60.9 m and 74% malaria cases were inhabited in the extent of 60 m near the water body, and the risk rate of people live there attacked by malaria was higher than others(OR = 1.6, 95%CI (1.042, 2.463), P < 0.05). The annual average temperature and rainfall may have close relationship with annual incidence. The average monthly temperature and rainfall were the key factors, and the correlation coefficients are 0.501 and 0.304(P < 0.01), respectively. Moreover, 75.3% changes of monthly malaria incidence contributed to the average monthly temperature (Tmean), the average temperature of last two months(Tmean01) and the average rainfall of current month (R mean) and the regression equation was Y = -2.085 + 0.839I1 + 0.998Tmean0 - 0.86Tmean01 + 0.16Rmean0. All the collected mosquitoes were Anopheles sinensis. The vectorial capacity and the basic reproductive rate of An. sinensis in two sites were 0.6969, 0.4983 and 2.1604, 1.5447, respectively. Conclusion. The spatial distribution between malaria cases and water-body, the changing of meteorological factors, and increasing vectorial capacity and basic reproductive rate of An. sinensis leaded to malaria re-emergence in these areas. © 2010 Zhou et al; licensee BioMed Central Ltd. Source
Shen Y.,U.S. Center for Disease Control and Prevention |
Shen Y.,Laboratory of Parasite and Vector Biology |
Shen Y.,Collaborating Center for Malaria |
Yin J.,U.S. Center for Disease Control and Prevention |
And 15 more authors.
Biomedical and Environmental Sciences
Objective Cryptosporidium spp. are prevalent globally and sheep are an important zoonotic reservoir. Little data regarding the rates of Cryptosporidium infections in ovines in China are available. This study assessed the prevalence of Cryptosporidium spp. in pre-weaned ovines from Aba Tibetan and Qiang Autonomous Prefecture in the Sichuan province of China. Methods A total of 213 fecal samples were collected from pre-weaned ovines and were examined microscopically (following modified acid fast staining). In addition, 18S rRNA genetic sequences were amplified from fecal samples by nested PCR and phylogenetically analyzed. Results The prevalence of Cryptosporidium in the collected samples was at 14.6% (31/213) and four isolates identified by PCR belonged to the Cryptosporidium cervine genotype (Cryptosporidium ubiquitum) demonstrating that this species was the primary sheep species found in sheep in China. Conclusion The present study suggested that the high incidence of Cryptosporidium in sheep poses a significant public health threat and that surveillance practices must be established to prevent zoonotic disease of humans. © 2011 The Editorial Board of Biomedical and Environmental Sciences. Source
Wang Y.,National Institute of Parasitic Diseases |
Wang Y.,Laboratory of Parasite and Vector Biology |
Wang Y.,Collaborating Center for Malaria |
Shen Y.-J.,National Institute of Parasitic Diseases |
And 19 more authors.
Chinese Journal of Schistosomiasis Control
Objective: To clone and express EgCyP gene of Echinococcus granulosus and analyze EgCyP using bioinformatics. Methods: Total RNAS of adult E. granulosus was extracted and reversedly transcripted to cDNA. EgCyP gene was amplified from cDNA and inserted into vector pET28a. Recombinant plasmid pET28a-EgCyP was transformed into E. coli BL21 (DE3) for expression under the induction of IPTG. The expressed product was identified by SDS-PAGE and Western blotting. EgCyP was analyzed by the bioinformatics software. Results: The EgCyP gene was successfully amplified from cDNA of adult E. granulosus and a fusion protein was expressed in E .coli BL21 (DE3). The molecular weight of the expressed protein was about 22 kDa. The Western blotting indicated that the antigenicity of the protein was specific. The bioinformatics analysis revealed that there were 7 antigen epitopes in EgCyP. Conclusion: EgCyP of E. granulosus is cloned and expressed in E. coli BL21 (DE3) successfully, which might be the foundation for the further study of its immunogenicity. Source