Table of Content

28 February 1999, Volume 17 Issue 1

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论著

A PILOT STUDY ON MALARIA CONTROL BY USING A NEW STRATEGY OF COMBINING STRENGTHENING INFECTION SOURCE TREATMENT AND HEALTH EDUCATION IN MOUNTAINOUS AREAS OF HAINAN PROVINCE *

CHENWenjiang;WUKaichen;LINMinghe;TANGLinhua;GUZhengcheng;WANGShanqing;LANChangxiong;LANXiuhan;LIHaiping;HUANGMingsan;CHENXiong;SHENGHuifeng;

1999, 17(1):  1-4. 

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　AIM: To explore a new malaria control strategy that fits current epiodemiological condition and coincides with modern medicine model and the principle of cost benefit.METHODS: The new strategy highlights the risk villages and risk population as the focal point and integrates health education with behavioral intervention. The main anti malaria measures consists of carrying out health education in risk villages, giving mass drug administrations in risk population staying overnight in the mountain, following up malaria cases for implementing radical cure,but without using traditional residual spraying or impregnating bednets with insecticides. RESULTS: After having adopted the new strategy and taken the control measures, the peoples knowledge about malaria increased to a higher level and the indices of malaria reduced to a lower level. The rate of bednet using in the population was increased from 26 8% to 72 6%.The annual parasite incidence (API) of malaria was declined from 3 5% in 1994 to 1 1% in 1996 and 0 8% in 1997, and the API of falciparum malaria was declined from 1 0% to 0 3% and 0 3% respectively in the townships at the same time. The parasite rate(PR) of malaria was declined from 7 2% in May, 1995 to 2 1% in November ,1996 and 1 2% in October,1997 and the PR of falciparum malaria was declined from 1 2% in May, 1995 to 0 1% in October,1997. The proportion of villages without malaria cases was increased from 18 6% in 1994 to 54 2% in 1997,and the number of risk villages with a malaria incidence above 5% was reduced from 14 to 2 at the same time. The ratio of cost/benefit was 1∶2 4 in 1995～1996 and 1∶4 4 in 1997, showing a better economic benefit.CONCLUSION: The expectant result has been obtained, thereby providing new experience for the malaria control in the mountainous areas of Hainan Province.


DETERMINATION OF CIRCULATING ANTIGEN IN URINE OF RABBITS INFECTED WITH SCHISTOSOMA JAPONICUM

XUEChunliang;LOUWenxian;WUChenyun;ZHANGEnying;XIEYanhui

1999, 17(1):  2-8. 

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　AIM:To develop an immunoassay for the detection of circulating schistosome antigen (CSA) in host urine.METHODS: CSA extracted from the urine of the rabbits infected with Schistosoma japonicum was used for preparing and selecting specific monoclonal antibody. A one step dot ELISA using this specific McAb and a 2nd antibody was used for detection of circulating schistosome antigen in the urine of infected rabbits. RESULTS: No CSA was detected in urine from all of 22 rabbits before infection. The positive rate of CSA in infected rabbits was correlated with the intensity of infection and the time of infection. No CSA was detected in the urine rabbits of 3 weeks after infection with 25 cercariae while the positive rate of CSA in the urine from rabbits infected with 200 cercariae was 40% and 100% after 3 and 6 weeks, respectively . A combination of CSA detection in both urine and serum may increase the detectability. CONCLUSION:The specific McAb prepared by urine CSA of Schistosoma japonicum infected rabbits can be used as a probe for detecting CSA in the urine of infected rabbits.


IN VIVO ANTI FECUNDITY EFFECT OF RECOMBINANT Sjc26 GST AGAINST SCHISTOSOMA JAPONICUM IN IMMUNIZED MICE *

JIANGJianmin;TULeming;ZHANGSue;XUMinyuan;LIUShuxian

1999, 17(1):  3-11. 

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　AIM: To observe the anti fecundity effect of recombinant Sjc26 GST against Schistosoma japonicum and its mechanism.METHODS:Male ICR mice were immunized with rSjc26 GST.Five days after final injection, mice of the immunization and control groups were challenged with 40±1 S.japonicum cercariae . All mice were sacrificed at 6 weeks after challenge.RESULTS: The worm reduction rate was 30 0%,and the egg reduction rates in the liver and in the spleen were 57 1% and 79 9%, respectively. Inhibition of the vitelline gland and testis was also observed by transmission electron microscopy. The number of vitelline globes, vitelline droplets and lipid droplets in the cytoplasm of vitelline cell and the number of lipid droplets in the supporting cells and the number of spermatids in the testis were apparently reduced.CONCLUSION:The damage of the main reproductive organs of Schistosoma japonicum was one of the factors responsible for rSjc26 GST bound anti fecundity action.


RECOMBINATION AND CLONING OF MSP1 19 AND PfCMR OF PLASMODIUM FALCIPARUM

LIXuerong;YUXinbing;LUOShuhong

1999, 17(1):  4-15. 

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　AIM∶ To construct a recombinant plasmid DNA encoding multiantigens of Plasmodium falciparum and to provide the requirements for DNA immunization. METHODS:Two oligonucleotide primers were designed to amplify MSP1 19 , the purified PCR products were digested by SalⅠ+XbaⅠ, and the recombinant plasmid pWR450 1/PfCMR was digested by EcoRⅠ+SalⅠ to recover PfCMR gene . PfCMR and MSP1 19 gene fragments were linked and recombined with mammalian expression vector pcDNA3. RESULTS:The MSP1 19 gene fragment with about 363 base pairs were specifically amplified by using PCR technique. The positive recombinant pcDNA3 PfCMR MSP1 19 (named pcDNA3 Pf8) was screened and identified by agarose gel electrophoresis,endonulease digestion and PCR technique, the whole length of Pf8 is 618 bp . CONCLUSION:By specifically amplifying MSP1 19 gene at the C terminal of MSP1,a recombinant plasmid pcDNA3 Pf8 encoding multiantigens of Plasmodium falciparum was successfully constructed.


DIFFERENCES IN HAEMOZOIN PRODUCTION AND PATHOGENICITY BETWEEN CHLOROQUINE SENSITIVE AND CHLOROQUINE RESISTANT STRAINS OF PLASMODIUM BERGHEI

YANJizhou;SONGGuanhong;GONGZhijing;LUYueliang

1999, 17(1):  5-20. 

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　AIM: To better understand the differences in haemozoin formation and pathogenicity between chloroquine sensitive(N) and chloroquine resistant(RC) strains of Plasmodium berghei. METHODS: IRC mice were grouped as follows: group XbaⅠ (Normal control, NC), group Ⅱ (control treated with chloroquine alone, CC), group Ⅲ (mice infected with N strain), group Ⅳ (mice infected with RC strain,RC) and group Ⅴ (mice infected with RC strain and treated with chloroquine, RCC). Morphologic features of the parasites, parasitaemia, histological and ultrastructural changes of livers among the groups were compared. RESULTS: Severe damages of the hepatic cells of the N group including increased lysosomes and swollen and fused mitochondria were detected. On the contrary, the prominent features in liver section of the RC group were inflammatory cell (notably mononuclear) infiltration and Kupffer cell activation. Numerous trophozoites and schizonts were sequestrated in hepatic sinusoids and less degeneration of parenchymal cells was found except for some swollen and vacuolated mitochondria. Internal food vacuoles containing haemozoin were found in the parasites of the N group, whereas external food vacuoles without haemozoin granules were arranged in foamy appearance within the parasitized cell of the RC group. CONCLUSION: P.berghei RC strain may modify the mode of ingestion and degradation of hemoglobin in the parasites, resulting in impeding haemozoin formation. The difference in virulence between the N and RC strain of P.berghei is probably attributed to the significant differences in the induction of immune response of the host.


TESTOSTERONE INHIBITS APOPTOSIS OF LEISHMANIA DONOVANI INFECTED MACROPHAGES*

QIAOZhongdong;GUOZhiyong;YINGuorong;YINLei;ZHAOJiahui;FrankWunderlich

1999, 17(1):  6-24. 

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　AIM: investigate the effect of the male sex hormone, testosterone (Te),on apoptosis of bone marrow derived macrophages (BMMs) from female C57BL/6j mice METHODS: Propidium iodide (PI) staining and transmission electron microscopy (TEM) techniques were used to investigate apoptosis specific morphological changes. BMMs derived from Te treated mice and Oil treated mice were challenged with Leishmania donovani (L.d. ), Oligo nucleosomal DNA were extracted 24 h post infection to detect apoptosis. RESULTS: The removal of M CSF from the medium could induce BMM apoptofsis. And the DNA fragmentation assay also indicated that: ① there was no difference in the amount of apoptotic cells between Te and Oil group; ② Te+L.d. group had significantly less dead cells than Oil+L.d. group demonstrating that Te could prevent apoptosis of macrophage infected with L.d. to a greater extent. CONCLUSION: Te inhibits apoptosis of the macrophages infected with L.d ., however, this inhibition did not occur in the macrophages uninfected with L.d. Te induced macrophage apoptosis inhibition may play an important role in Te induced immunosuppression.


OBSERVATION ON THE CL INICAL SYM PTOM S ANDSPOROCYST EXCRETION IN HUMAN VOLUNTEERSEXPERIM ENTALLY INFECTED W ITH SARCOCYSTIS HOM IN IS

CHENXinwen;ZUOYangxian;ZUOWeiwei

1999, 17(1):  7-27. 

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　A IM: To investigate the excretion of sporocysts and clinicalm anifestations in humans experimentally infected of Sarcocystis hominis. METHODS: Three vo lunteers were infected by eating raw beef containing cysts of S.hominis. One ingested about 1567 cysts in skeletalmuscles of a naturally infected cattle; two volunteers each ingested about 14740 cysts from an experimentally infected water buffalomeat. Fecalex-amination by zinc sulfate flotation m ethod was conducted daily sinced4 post infection (pi). RESULTS: ree
spo rocyst s and oocysts were found in their faeces from d11～40, d12～ 23, d10～30 pi , and peaked at d18, d14, d14.All of them presented clinical symp toms such as abdominal pain, distension, watery diarrhea and eosinoph ilia 1 w k～4 wkpi and were spontaneou slycured with in 29 days piwithout taking any medicine.CONCLUSION: All the experime tally infected persons had gast rointest inal symptoms and passed sporo-cysts and oocysts in faeces 10～ 12 days after infection and persisted for 11～29 days.

DIAGNOSIS OF TRICHINOSIS BY INDIRECT FLUORESCENT ANTIBODY TEST WITH TRICHINELLA LARVA SECTION *

CUIJing;WANGZhongquan;WUFeng;JINXuexiang;ZHANGPengyuan;YANGRuiqin;LIUJun

1999, 17(1):  8-31. 

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　AIM: To evaluate the value of indirect fluorescent antibody test (IFAT) in diagnosing trichinosis. METHODS: IFAT using frozen section of the purified Trichinella larvae as antigen was employed to detect anti Trichinella antibodies in sera from mice infected with Trichinella spiralis and the patients with trichinosis. Sera from patients with trichinosis were collected at different time intervals after onset of the disease and after treatment with albendazole. Sera from patients with other parasitic diseases and healthy individuals were used as control. RESULTS: The anti Trichinella antibodies were detected in 15 infected mice as early as 2 weeks after infection,and in 86 5% of 467 patients with trichinosis. Sera from patients with filariasis, echinococcosis and healthy controls were all negative. 8 of 48 (16 7%) cases with paragonimiasis showed positive cross reaction. The antibody positive rate of patients with trichinosis was 70 2% one week after onset of disease and increased to 91 0%,95 8% and 100% at two, three and four weeks after onset, respectively. The frozen section of the larvae can be stored at -20℃ for 5 years without loss of antigenicity. The IFAT positive rate was increased from 87 5% before treatment to 100% one week after treatment, and the serum antibody titers were elevated as well. The antibody negative conversion rate of the patients was 24% at one month after teratment and increased to 75% at four months after treatment. CONCLUSION: IFAT using frozen section of the purified Trichinella larvae as antigen is highly sensitive and specific for the diagnosis of trichinosis and evaluation of the therapeutic effect.


CHANGES IN CHLOROQUINE RESISTANCE OF PLASMODIUM FALCIPARUM IN HAINAN PROVINCE 

LIUDequan;CAIXianzheng;RENDaoxing;LIURuijun;LINShigan;ZENGLinhai;TANGXian

1999, 17(1):  9-34. 

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　AIM:To observe the variation in resistance of Plasmodium falciparum after the cessation of chloroquine medication. METHODS:WHO standard in vitro microtest and in vivo test were used. RESULTS: In vitro test showed that the rate of chloroquine resistant P.falciparum dropped from 97.9% in 1981 to 26.7% in 1997 ( P<0.001). The mean concentration of chloroquine for complete inhibition of schizont formation declined from 10.46±7.14 pmol/ul blood in 1981 to 1.63±1.47 pmol/μl blood in 1997( P<0.001). In vivo test showed that the rate of chloroquine resistant P.falciparum decreased from 84.2% in 1981 to 18.4% in 1997 (P<0.001) . The proportion of RⅢ cases to the total resistant cases dropped from 53.1% in 1981 to 14.3% in 1997. CONCLUSION:A tendency of progressive decline of resistance of the parasite was revealed after the cessation of chloroquine medication.


EXPERIMENTAL THERAPY OF PAGUMOGONIMUS SKRJABINI INFECTION IN RATS WITH TRICLABENDAZOLE

GAOJingsong;LIUYuehan;WANGXiaogen;YUdengao;SUQun;LIU

1999, 17(1):  10-38. 

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　AIM: To observe the therapeutic effect of triclabendazole in rats infected with Pagumogonimus skrjabini . METHODS:Metacercariae of P. skrjabini were isolated from crabs( Sinopotamon )collected from two endemic areas(Weiyuan County of Sichuan Province and Wansheng District of Chongqing Municipality).Wistar rats were each infected intraperitoneally with metacercariae .One month and two months after infection,the infected rats were treated with triclabendazole at the total dosage of 300 mg/kg over 2 days , 450 mg/kg over 3 days and 600 mg/kg over 3 days, respectively. RESULTS:The worm reduction rates were 50%, 80% and 87% respectively one month after completion of treatment. Dead worms (about 1 mm size) recovered from the muscles,liver,abdominal cavity ,chest cavity and lungs were signicantly diminished in size and weight in comparison with those of the control group . Many large (about 1 cm )black colored distended worm cysts usually with two adult worms and many eggs were found in the lungs of the control rats. Most worm cysts in the treated groups of rats were found to be atrophied, changing into hemorrhagic necrotic patches.CONCLUSION:Triclabendazole is highly active against P. skrjabini in rats.


MOLECULAR CLONING OF A cDNA ENCODING AN ANTIGENIC POLYPEPTIDE CONTAINING REPEAT UNITS OF SPIROMETRA ERINACEIEUROPAEI PLEROCERCOID*

LIUDianwu;LIUDianjun;LENGShuangying;LIUShuxian

1999, 17(1):  11-42. 

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　AIM:To study the gene structure encoding some antigenic polypeptides of plerocercoid of Spirometra erinaceieuropaei (SEP). METHODS:A cDNA library constructed from SEP was immunoscreened using mouse anti SEP polyclonal antibody.The gene structure was analyzed by computer after the insert of positive clone was subcloned and the nucleotide sequences of the insert were determined.The length of mRNA hybridized with cDNA was detected by Northern blotting. RESULTS:A cDNA clone of 1 084 bp encoding an antigenic polypeptide was isolated. The clone contained one open reading frame composed of 828 bp encoding 276 amino acids.The open reading frame contained tandem repeating unit of 123 bp which appeared 5 times in this clone.The 41 amino acids deduced from 123 bp repeating unit consisted of 53 7% of hydrophobic amino acid residues.In Northern blot assay of poly (A) +RNA,a strong band of about 1 1 kb and a weak band of about 1 7 kb were found in the plerocercoids but no band was found in the adult worms. CONCLUSION:The repeating element derived from the plerocercoids may be associated with the migration of the plerocercoids in the host tissue.The polypeptides with repeating element may act as evasive antigens of the parasite to escape from the destruction of host immune reactions.


实验研究

ASSAY OF SENSITIVITY OF PLASMODIUM FALCIPARUM TO CHLOROQUINE,AMODIAQUINE,PIPERAQUINE, MEFLOQUINE AND QUININE IN YUNNAN PROVINCE *

YANGHenglin;LIUDequan;HUANGKaiguo;YANGYaming;YANGPinfang;LIAOMingzheng;ZHANGChunyong

1999, 17(1):  12-45. 

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　AIM:To determine the sensitivity of P.falciparum to chloroquine,amodiaquine,piperaquine,mefloquine and quinine in Yunnan Province of China in 1992～1995.METHODS:Rieckmanns in vitro microtechnigue was used. The sensitivity of P.falciparum was tested to the above mentioned antimalarials.RESULTS: The resistance rates of isolates of P.falciparum from the south, southeast and the west part of Yunnan to chloroquine and amodiaquine were 96 7%(29/30),78 9%(30/38),95 7%(22/23) and 100%(30/30),85 3%(29/34),8/9, respectively,with their corresponding ID 50 of 125 nmol/L,136 nmol/L and 176 nmol/L, and 52 nmol/L,64 nmol/L and 72 nmol/L,respectively.All the isolates were sensitive to quinine and their ID 50 were 480 nmol/L ,352 nmol/L,608 nmol/L ,respectively. The resistance rates of P.falciparum from the south part and southeast part of Yunnan to piperaquine were 96 4%(27/29),72 9 (27/37),respectively,their ID 50 were 320 nmol/L and 228nmol/L;all the cases were sensitive to mefloqine,their ID 50 were 68 nmol/L and 88 nmol/L. CONCLUSION: P.falciparum generally produces resistance to chloroquine, amodiaquine and piperaquine in Yunnan Province; the degree of resistance to chloroquine of P.falciparum from the west part of Yunnan were higher than the P.falciparum from the southeast part of Yunnan;all the isolates were sensitive to mefloquine and quinine in this region.