Malaria Situation in the People's Republic of China in 2005 / 中国寄生虫学与寄生虫病杂志

Totally,42 319 malaria cases and 57 787 suspected cases with 48 deaths were reported by the Annual Case Repor-ting System in 1186 counties of 21 Provinces/Municipality/Autonomous Region(P/M/A) in 2005,and the annual incidence was 0.59/10 000,an increase of 55.3% than that of the last year.Through the Case Reporting Information System,an internet reporting process started in 2004,40 371 malaria cases were reported from 1 075 counties of 31 P/M/A.The number of malaria cases and the rank of P/M/A were basically in concordance by the two systems.Among the 1186 counties with reported malaria cases,27 counties had an incidence of more than 10/10 000 distributed in Yunnan(15 counties),Hainan(7 counties) and Anhui(5 counties).There were 80 counties in which the malaria incidence was between 1/10 000 and 10/10 000.The number of Plasmodium falciparum malaria cases was 4 146,accounting for 9.8% of the total cases,of which 63.5%(2 632) were imported cases in 178 counties/cities of 18 P/M/A.Indigenous falciparum malaria was found in 47 counties/cities of Yunnan and Hainan Provinces,of which 31 counties/cities were in Yunnan,increased by 29,16 counties/cities were in Hainan,same with that of 2004.Yunnan and Hainan Provinces are still relatively high transmission areas.Yunnan ranked No.2 in the country in terms of the number of cases while Hainan ranked No.1 by malaria incidence in 2005.19 588 malaria cases were reported from the two provinces in 2005,accounting for 46.3% of the total reported cases in the country.There were 15 072 cases with 38 deaths reported from Yunnan,the incidence was 4.95/10 000,an increase of 60.2% than that in the last year.Among the reported cases,3 497 were falciparum malaria with 69.0% imported from the bordering nations.The number of reported cases in Hainan was 4 516,with an incidence of 5.46/10 000,53.1% decrease than the last year.In central China,the resurgence of malaria was considerable in provinces along the Huai River,especially in Anhui Province.The number of malaria cases in Anhui came to the highest in the country in 2005,with 15 681 malaria cases and 7 662 suspected cases reported,accounting for 37.5% of the total cases in the country,and an incidence of 2.45/10 000,increased by 77.5% than that in 2004.The number of reported cases in Henan Province was 2 349,increased by 55.2% in incidence.Hubei Province reported 1 564 malaria cases with an incidence of 0.27/10 000,decreased by 42.6%.651 cases were reported from Jiangsu Province,almost the same as that in 2004.Focal outbreaks occurred in 277 villages of 20 counties in Anhui,Hubei and Jiangsu,where Anopheles sinensis is the principal transmission vector.Malaria cases reported from the above 4 provinces accounted for 47.8% of the national figure,increased approximately by 10% than the last year.Cases reported from P/M/A in the South and East China occupied about 4.9% of the total,similar to that in 2004.Several hundreds were reported from each of Guizhou,Sichuan,Guangxi,Guangdong,Zhejiang,Shanghai and Hunan.Less than 100 cases were reported from each of Fujian,Chongqing,Shandong,Shanghai,Jiangxi,Liaoning,Shaanxi,Shanxi and Gansu Provinces in 2005.High attention should be paid to Guizhou and Tibet.Focal outbreaks occurred in Guizhou for consecutive 4 years,and malaria cases in 2005 double increased than the last year.77.8% of the reported cases were indigenous patients,which implied that local transmission resulting from imported malaria cases has become a major problem in Guizhou.93 malaria cases were reported from Linzhi District of the Tibetan Autonomous Region in 2005,76 cases more than that in 2004.In summary,malaria is still an important problem of public health in China,especially in the southern and central parts.Yunnan and Hainan still faced a severe situation of malaria endemics with the spread of Plasmodium falciparum,especially imported malaria in the 25 border counties in Yunnan.In the central part of the country,especially Anhui Province,the malaria prevalence was highly unstable with frequent focal outbreaks in areas along the Huai River,which revealed new challenges to the malaria control program in China.In addition,more attention needs to be paid to the malaria control in Guizhou and Tibet.

In vitro Potentiation of Chloroquine Activity in Plasmodium falciparum by Ketotifen and Cyproheptadine / 中国寄生虫学与寄生虫病杂志

Objective To study the potentiation of chloroquine activity and mechanism by ketotifen and cyproheptadine in in vitro cultured Plasmodium falciparum Fcc SM1/yN strain. Methods In vitro cultured Fcc SM1/yN strain was added to pre-prepared drug plates at 50 ?l/well after synchronization to make final concentration of 0.312 5-2 560 nmol/L for chloroqine and of 9.80-5 000 nmol/L for ketotifen or cyproheptadine. After 34 hours' culture in 37 ℃, the number of schizonts with 3 or more nuclei was calculated among 200 parasites under microscope. Calculated half inhibitive concentration ( IC50 ) of chloroquine and every drug combination to parasite as well as chloroquine activity enhancement index ( AEI) of ketotifen (or cyproheptadin) . Time dependency of potentiation was studied. All data were analyzed statistically with SPSS 13.0. After 20 hours' action of one optimal combination dose of chloroquine/ketotifen or chloroquine/cyproheptadine, RNA of the Fcc SM1/yN strain was extracted and real-time PCR was used to determine the expression level of pfcrt and pfmdr1 genes. Results The best potentiation effect was observed with ketotifen or cyproheptadine of 625 nmol/L, with IC50 of 74.53 nmol/L for chloroquine/ketotifen and 89.7 nmol/L for chloroquine/cyproheptadine respectively, and activity enhancement index (AEI) of 0.42 for chloroquine/ketotifen and 0.30 for chloroquine/cyproheptadine respectively. Combination of 625 nmol/Lketotifen or cyproheptadine with 5 nmol/L chloroquine showed the highest potentiation potency. 6-7 hours during which ketotifen or cyproheptadine was added after chloroquine showed the highest effect, with IC50 of 67.70 nmol/L for chloroquine/ketotifen and 81.53 nmol/L for chloroquine/cyproheptadine respectively, and the AEI was 0.47 for chloroquine/ketotifen and 0.37 for chloroquine/cyproheptadine respectively. After action of chloroquine/ketotifen or chloroquine/ cyproheptadine at one optimal combination dose, expression level of pfcrt gene increased by 91% and that of pfmdr1 gene decreased by 14% respectively. Conclusion Appropriate combination of chloroquine/ketotiphen or chloroquine/ cyproheptadine potentiates chloroquine against in vitro cultured P. falciparum. 6-7 hour period is an optimal time when ketotifen or cyproheptadine was added after chloroquine. Potentiating activity of ketotifen and cyproheptadine may be related to the expression level of pfcr t and pfmdr1 genes.

Protective Immunity Induced by Recombinant Schistosoma japonicum Thioredoxin in Mice / 中国寄生虫学与寄生虫病杂志

Objective To investigate the protective immunity of the recombinant thioredoxin of Schistosoma japonicum(reSjcTrx)in mice. Methods Thirty 6-week old female C57BL/6 mice were randomly divided into 3 groups with 10 each: reSjcTrx with Montanide ISA720 adjuvant, adjuvant control, and infection control. Mice were vaccinated subcutaneously at week 0, 2, 4 with reSjcTrx emulsified in Montanide ISA720 adjuvant. The mice in adjuvant group was injected three times with Montanide ISA720 and saline only. Mice in infection control group were given no injection. Three weeks after final injection, each mouse was challenged with 30?1 cercariae of S. japonicum (Chinese strain). At the week six after challenge, all mice were sacrificed and perfused. The number of recovered worms and eggs from liver tissue of mice were counted. Sera were collected from mice before immunization, before challenge and before killing. The anti-SjcTrx antibodies in sera were detected with ELISA. Results ELISA showed a high level of specific IgG antibodies in mice immunized with the reSjcTrx. The worm reduction rate and egg reduction rate of reSjcTrx immunization group were 22.8% and 29.5% respectively, significantly higher than those of the control groups (P﹤0.05). SDS-PAGE and Western blotting revealed that the molecular weight of expressed protein was around Mr 14 000 and could be recognized by sera from rabbit infected with S.japonicum and from mice immunized with reSjcTrx. Conclusion The reSjcTrx induces certain protective immunity against schistosomiasis japonica in mice.

Molecular Variation Based on mtDNA-COII Gene of Members of the Anopheles minimus Group / 中国寄生虫学与寄生虫病杂志

Objective To investigate intra and inter species molecular variations and phylogeny of the five members of the Minimus Group of Anopheles subgenus Cellia in China: An. aconitus, An.varuna, An.jeyporiensis, An.minimus A and An.minimus C, and to report the DNA sequence divergence among these species at a mitochondrial locus (cytochrome oxidase II). Methods Single mosquito′s legs were digested to extract DNA. COII gene was amplified, sequenced and analysed; and the phylogenetic tree of members of An.minimus group was reconstructed by maximum likelihood method (DNAML). Results and Conclusion The data confirmed the presence of two cryptic species, A and C, within An.minimus complex in the research localities; and two species differed by 2.3% in the COII sequences owing to 16 nucleotide substitutions. There was less variation between the two species than other members of the Minimus Group.

Study on a Grey Model for Evaluation of Anopheles minimus Density / 中国寄生虫学与寄生虫病杂志

wet season temperature_max. The An. minimus density evaluation model was derived as follows: y=0

Preparation of Monoclonal Antibodies Specific to Lactate Dehydrogenase of Plasmodiun falciparum / 中国寄生虫学与寄生虫病杂志

Objective To prepare monoclonal antibodies specific to lactate dehydrogenase of Plasmodiun falciparum. Methods The Plasmodium falciparum lactate dehydrogenase (pLDH) gene was amplified from whole blood of malaria patients by PCR and cloned into expression vector pGEX-3X. Recombinant pLDH protein was expressed and purified, and used for immunizing mice to prepare monoclonal antibodies (McAbs). The McAbs were characterized by Western blotting analysis. Results The Plasmodium falciparum lactate dehydrogenase gene was amplified and cloned into expression vector pGEX-3X. The recombinant pLDH plasmid was expressed in E.coli) BL-21 cells. 15 cell lines of McAbs with high titer against pLDH were obtained using the recombinant pLDH as immunogen. Western blotting analysis showed that these McAbs recognized a Mr 33 000 of native Plasmodiun falciparum protein without cross-reaction with constituents of red blood cell of febrile patients from endemic area of malaria. Conclusion Fifteen hybridoma cell lines secreting high titer of McAb specific to Plasmodium falciparum LDH were established based on the recombinant pLDH.

Preparation of DNA from Cryptosporidium parvum Oocysts for PCR Detection / 中国寄生虫学与寄生虫病杂志

Objective To establish three methods of DNA extraction from Cryptosporidium parvum oocysts and test by PCR. Methods After three freeze-thaw cycles, three kinds of templates were extracted from the oocysts by Chelex-100, phenol/chloroform or genomic DNA purification system kit, and used for PCR detection. According to the sequence of a C.parvum gene (L16996), a pair of primers was designed and synthesized, and used for PCR. The sensitivity of the template by Chelex-100 method was also tested by PCR. Results One 446 bp PCR product was observed by agarose gel electrophoresis for all three kinds of templates. The PCR sensitivity by Chelex-100 extracted DNA reached for detection of a specimen containing only 1/2 oocyst. Conclusion The three kinds of extraction can all be served as templates for PCR detection of C.parvum oocysts, while Chelex-100 method is simpler, quicker and more reliable for DNA extraction of the parasite.

The Role of Anopheles anthropophagus in Malaria Transmission in in Xinyang City of Henan Province / 中国寄生虫学与寄生虫病杂志

Objective To study the role of Anopheles anthropophagus in malaria transmission and transmission threshold so as to provide basis for vector surveillance and malaria control strategy. Methods Parasitological and entomological methods were used in the investigation at 5 villages of Xinyang City, Henan Province. Results From July to August, 1999, 74 febrile cases (10^9% of the total population) were examined. Among them 50 were infected, the incidence in the population of surveyed spots was 7^4%. Active detection was made in another randomly selected two villages and found that the parasite rate in the inhabitants was 2^0%, and the positive rate of IFA was 8^4%. Only vivax malaria was detected. An.anthropophagus and An.sinensis were collected, with An.anthropophagus as the predominant one in human dwellings. The estimated man\|biting rate and the human blood index were 4^9388 and 0^7858 respectively. The vectorial capacity of An. anthropophagus was 5^5296. The critical man\|biting rate of An.anthropophagus was 0^2407 as calculated by the formula (ma=-rlnP/abP\+n) according to Macdonald′s model.The local man\|biting rate was 20 times higher than that of the critical man\|biting rate. Conclusion The results demonstrated that An.anthropophagus is the principal vector in malaria transmission in the area. The findings imply that the critical man\|biting rate is of practicable importance in vector surveillance.

Research Progress on Chloroquine Resistance in Plasmodium falciparum and Resistance Reversal Agent / 中国寄生虫学与寄生虫病杂志

Emergence and broad spread of chloroquine resistance urge human beings to change drug policy in malaria control and to find more effective new drugs. Nevertheless, chloroquine is still used in the treatment of falciparum malaria in some poor endemic regions due to economic and development reasons. It should be of great significance to un-derstand the mechanism of chloroquine resistance and find the way to reverse it in order to bring chloroquine with high efficacy and low cost back to the first line of the combat to malaria. Advent and development of resistance reversal agents provide a new clue for this purpose. When used together with chloroquine, it can partly restore the efficacy of chloroquine in resistant Plasmodium falciparum. The article summarizes the research progress on chloroquine resistance in P. falciparum and resistance reversers.

Study on the Feasibility for ARIMA Model Application to Predict Malaria Incidence in an Unstable Malaria Area / 中国寄生虫学与寄生虫病杂志

Objective To explore the application of seasonal time series ARIMA model in prediction of malaria incidence in an unstable malaria area. Methods SPSS13.0 software was used to construct the ARIMA model based on the monthly malaria incidence of Huaiyuan and Tongbai counties in Huaihe River Valley, from Jan. 1998 to Dec. 2005, with consideration of residual un-correlation and concision. Akaike′s information criterion (AIC) and Bayesian information criterion (BIC) were used to confirm the fitness of model. The constructed model was then applied to predict the monthly malaria incidence in 2006 and the incidence from ARIMA model was compared with the actual incidence, so as to evaluate the model′s validity. Malaria incidence of 2007 was predicted by ARIMA model based on malaria incidence from 1998 to 2006. Results Statistics assisted estimation of the significance of the fitted autoregressive and seasonal moving average coefficients (AR1=0.512, SMA1=0.609, P

Isolation and Identification of an Isolate of Cow-origin Cryptosporidium sp / 中国寄生虫学与寄生虫病杂志

Objective To isolate and identify Cryptosporidium oocysts from feces of naturally infected cow. Methods Fecal samples were collected from Cryptosporidium infected cows confirmed by modified acid-fast staining method. Oocysts were isolated and purified with Sheather sucrose density gradient centrifugation technique. Genomic DNA was isolated with Chelex-100. Both primers were designed to amplify Cryptosporidium small subunit ribosome RNA gene (SSU rRNA) and Cryptosporidium oocyst wall protein gene (COWP), respectively. The PCR products were cloned into pGEM-T and pGEM-T Easy vector and sequenced subsequently. Homology and phylogeny were analyzed with BLASTn and MEGA software. Results The results suggested that the size of oocysts was (7.4?0.32)?m by(5.4?0.21)?m and the ratio of length and width was 1.37?0.07 (n=20). BLASTn revealed that the identity of SSU rRNA and COWP gene of Cryptosporidium isolated from cow to the counterparts of C.andersoni was 100% and 99% respectively. Phylogenetic reconstruction placed the isolated Cryptosporidium within the C.andersoni clade based on the sequence of SSU rRNA and COWP gene. Conclusion What isolated from naturally infected cow feces has been identified as C. andersoni.