Table of Content

30 November 1986, Volume 4 Issue 4

Previous Issue    Next Issue

INTEGRATED APPROACH IN MALARIA CONTROL INCLUDING ENVIRONMENTAL MANAGEMENT TO REDUCE MAN-MOSQUITO CONTACT AND REDUCTION OF INFECTION SOURCE IN HUANGHUAI PLAIN

1986, 4(4):  246-250. 

Asbtract ( )   PDF (343KB) ( )  

Related Articles | Metrics

The study was carried out from 1980 to 1985 in Daisan township with a population of 26 000 in Huang-huai Plain, an endemic area of vivax malaria transmitted by An. sinensis. Since the development of irrigation system and water conservancy and the expansion of rice fields in the fifties have brought forth an increase in human-mosquito contact and the vectorial capacity in the Plain, the number of malaria cases increased significantly and the single measure of mass drug administration (MDA) could not bring about the desired effect of malaria control. Considering conjointly the bionomical behaviour of An. sinensis, the sole vector for malaria transmission, the human behaviour of villagers and local conditions, an integrated approach was under trial and assessed parasitologically, serologically, and entomologically. The approach included motivating the villagers to sleep indoors and to use bed-nets, improving ventilation in houses by installing back windows and reducing human infection source by MDA and case treatment.The annual parasite incidence (API) of malaria decreased from 181‰ in 1980 to 0.45‰ in 1985. Although MDA was stopped in 1983-1985, malaria incidence continued to decrease. It has been shown that the reduction of human-mosquito contact could bring about the decrease of the man-biting rate, the human blood index and the vectorial capacity of An. sinensis and the transmission rate of malaria. It is a successful field trial of the integrated approach for malaria control in the area concerned.

OPSONIZATION AND CYTOTOXICITY OF MONOCLONAL ANTIBODIES AGAINST PLASMODIUM FALCIPARUM

1986, 4(4):  251-255. 

Asbtract ( )   PDF (876KB) ( )  

Related Articles | Metrics

The abilities of McAbs to enhance the phagocytosis of Plasmodium falciparum by peritoneal macrophages and the killing of parasites by peritoneal cells free of adherant cells were evaluated by in vitro assay. Four of six McAbs, which recognized parasite antigens expressed only on segmentors and free merozoites of P. falciparum by immuno-fluorescence, augmented the phagocytosis of the parasites 2-4 times that of SP2/0 ascitic fluid. Enhanced McAbs-media ted phagocytosis as a result of opsonization of the parasite was demonstrated by preincubating macrophages with McAbs prior to the phagocytic assay. Four of seven McAbs examined showed cytotoxic activity on P. Jalciparum. Peritoneal cells free of adherent cells were capable of killing the parasites in the presence of McAb. The results indicate that there may be "mono-function", "bifunction" and "multi-function" types of McAbs against P. Jalciparum. The putative protective antigen of malaria parasite purified by "multifunctional McAb" affinity chromatotraphy may have potential interest as a vaccine against the parasite or as an immunodiagnostic material.

COMPARISON OF EFFECTIVENESS BETWEEN TWO KINDS OF MEDIA FOR IN VITRO MICROTEST OF SENSITIVITY OF PLASMOD1VM FALCIPARVM TO CHLOROQUINE AND MEFLOQUINE

1986, 4(4):  256-259. 

Asbtract ( )   PDF (284KB) ( )  

Related Articles | Metrics

This paper deals with a comparison between two kinds of media, WHO supplied standard medium and home-made lyophilized medium, carried out for two years in Ledong County, Hainan Island, China. All isolates were separately determined on chloroquine plates and mefloquine plates with both media by the standard technique.On chloroquine plates, of 23 isolates, 17 were interpretable (successful rate 73.9%) in 1982, 18 of 22 isolates (successful rate 81.8%) in 1983. In control wells the maturation rate from ring form to schizont was 10-97% (average 43.1%) in 1982, and 14-100% (average 51.6%) in 1983, the number of nuclei per schizont was 3-10 (average 5.0) in 1982, and 3-6 (average 4.7) in 1983 with wHO supplied medium, while the successful rate was 100%, the maturation rate was 13-100% (average 60.8), the number of nuclei per schizont was 4-12 (average 7.9) in 1982 and 100%, 14-100% (57.2%) and 4-8 (5.6) respectively in 1983 with lyophilized medium.On mefloquine plates, 15 of 23 isolates were interpretable (65.2%). In control wells 16-97.5% of schizonts matured (42.7%), the number of nuclei per schizont was 2-8 (4.7) in 1982 and 81.8%, 16-95%(50.9%) and 3-6(4.6) respectively in 1983 with WHO supplied medium, while the successful rate was 87% with lyophilized medium, the maturation rate was 18-100%(56.7%), the number of nuclei was 2-13 (7.3) in 1982 and 100%, 13-100%(57.1%) and 4-8 (5.6) respectively in 1983.This study indicated that the effect of lyophilized medium on supporting Plasmo dium falciparum growth was better than that of WHO standard medium. The lyophilized medium has the advantages of easy carrying and time-saving and is more applicable under field conditions.

EFFECTS OF QINGHAOSU ON THE SURFACE STRUCTURE OF ERYTHROCYTES INFECTED WITH PLASMODIUM BERGHEI AND THE ERYTHROCYTE-FREE PARASITES

1986, 4(4):  260-262. 

Asbtract ( )   PDF (961KB) ( )  

Related Articles | Metrics

With scanning electron microscope, the surface structure of erythrocytes of the normal mice, of the mice infected with P. berghei and the erythrocyte-free parasites was observed. The results revealed three types of alterations on the surface of about 25% of the erythrocytes infected with P. berghei: 1. Obvious deepening of the ery-throcytic concavities; 2. small and deep invagination of the erythrocyte surface membrane; 3. crater-like pits on the erythrocyte surface. All of the altered portions mentioned above are named as "metabolic window". The erythrocyte-free P. berghei has a relatively smooth surface. The free malarial parasites are spherical with an average diameter of 3.2μm.Qinghaosu at the oral dose of 1.2g/kg had no appreciable effect on the surface of normal erythrocytes nor on that of the erythrocytes infected with P. berghei. Furthermore, no marked changes on the free malarial parasites were found 4 hours after the medication of qinghaosu. However, the erythrocyte-free parasites became significantly smaller and irregular in shape in the late period under qinghaosu action.

ULTRASTRUCTflRAL STUDY ON THE EFFECT OF PYRONARIDINE ON ERYTHROCYTIC STAGES OF CHLOROQUINE-RESISTANT STRAIN OF PLASMODIUM BERGHEI

1986, 4(4):  263-266. 

Asbtract ( )   PDF (1114KB) ( )  

Related Articles | Metrics

15 min-24h after the administration of pyronaridine (6 mk/kg, ED50) to the mice infected with chloroquine-resistant strain of Plasmodium berghei, the morphological changes of the erythrocytic stages were observed under electron microscope. The action of the drug appeared to be primarily on the pellicular complexes in the tro-phozoites which showed swelling, and became whorled multilamellate. The modification developed progressively. Subsequently, mitochondria became swollen, endoplasmic reticulum disappeared, ribosomes blurred and nucleus became more electron-dense. Finally, small, disrupted, dead parasites were detected. In contrast, no significant ultrastructural changes could be found in most of the erythrocytic stages of the parasites after the chloroquine administration (400mg/kg) to the infected mice.

EMBRYOTOXICITY OF AMIDANTEL IN MICE

1986, 4(4):  267-268. 

Asbtract ( )   PDF (141KB) ( )  

Related Articles | Metrics

Amidantel, a new broad spectrum anthelmintic, was studied for its teratogenicity in mice. The mice were given orally the drug in a dose of 60, 30, 15mg/kg/d X 10 ((?)1/10, 1/20, 1/40 LD50) during d6 to d15 period after gestation. A known teratogen, dexon, at the dosage of 20mg/kg/d X 10 was usod as positive control. Pregnant mice were sacrificed on d18 and fetuses were subjected to tetratological investigation. The results showed that amidamel did not manifest significant embryotoxicity in our experiments.

IN VITRO ACTIVITY OF CHLOROQUINE, TWO ENANTIOMERS OF CHLOROQUINE, DESETHYLCHLOROQUINE AND PYRONARIDINE AGAINST PLASMODIUM FALCIPARUM

1986, 4(4):  269-271. 

Asbtract ( )   PDF (209KB) ( )  

Related Articles | Metrics

A 48 hour in vitro test was conducted to compare the susceptibility of chloro quine-sensitive strain and chloroquine-resistant strain of Plamodium falciparum to chloroquine, two enantiomers of chloroquine, desethyl-chloroquine and the new antimalarial drug pyronaridine. All the 5 compounds similarly inhibited the chloroquine sensitive-strain. However, pyronaridine was much more active than chloroquine and its enantiomers against the chloroquine-resistant strain, whereas desethylchloroquine was less active.

A COMPARATIVE STUDY OF COP AND IHA IN THE EPIDEMIOLOGICAL EVALUATION OF SCHISTOSOMIASIS JAPONICA IN ERADICATED ENDEMIC AREA

1986, 4(4):  272-276. 

Asbtract ( )   PDF (355KB) ( )  

Related Articles | Metrics

In 18 villages with schistosomiasis basically eradicated for 5 to 15 years and with proportions of cured patients ranged from 2.3% to 63.9%, a comparative study was performed between COP and IHA to see if they could be of use in the evaluation of disease control. A total number of 4 361 residents were examined and the results showed that in these villages with the disease controlled for more than 10 years the reaction rate and the mean oircumoval precipitin rate of the cohorts with past history were all similar to those without previous history of schistosomiasis, and those of the patients cured for more than 10 years were as low as those of the villagers without any history of the disease. However, the GMRT as well as the reaction rates of IHA in both cohorts in these villages differed significantly, and so did the 2 patient groups cured for more or less than 10 years.A relationship of multiple regression was presented among the mean circumoval precipitin rate of COP, the number of years for a successful basic eradication of thedisease (X1) and the rate of population with past history of schistosomiasis (x2) inthe given areas. The equation of the regression is Y=- 0.0198X1+ 0.0030x2+0.2744.This equation can be used to express the range of eradication of the disease after COP survey in an unknown area.

APPLICATION OF DOT-ELISA IN DIAGNOSIS OF SCHISTOSOMIASIS

1986, 4(4):  277-279. 

Asbtract ( )   PDF (207KB) ( )  

Related Articles | Metrics

Dot-ELISA was, for the first time, used in the diagnosis of schistosomiasia japonica. Among 63 confirmed schistosomiasis cases 88.9-96.8% showed positive reactions while none of the sera of 65 normal controls reacted. Cross reaction occurred in some degree with sera from paragonimiasis and clonorchiasis cases. It is considered that Dot-ELISA could be used as a supplement in the diagnosis of schistosomiasis.

APPLICATION OF ELJSA TO DIAGNOSIS AND SEROEPIDEMIOLOGICAL SURVEY OF FILARIASIS

1986, 4(4):  280-283. 

Asbtract ( )   PDF (289KB) ( )  

Related Articles | Metrics

Through antibody determination by ELISA of 68 sera from patients infected with B. malayi and 85 with W. bancrofti, it was found that 3 soluble antigens, adult worm and microfilariae of B. malayi and D. immitis adult antigen, possessed similar sensitivity. Adult worm antigen is considered to be the most promising in practical application, because it is relatively easy to obtain from artificially infected jirds and to prepare. The sensitivity of ELISA with adult worm antigen was 92.6% for malayan cases and 83.3% for bancroftian cases, its specificity being 98.8%.59 and 85 previous microfilaremia cases, who had becn treated with DEC or furapyrimidone 5 and 10 years ago were examined by ELISA, 30.5% and 16.5% of them remained positive, respectively. A seroepidemiological survey on filariasis by ELISA were carried out in 818 inhabitants living in 4 endemic villages, one of malayan and 3 of bancroftian types. The detection rate by ELISA was parallel to the microfilaraemia detection rate, the lowest being in children aged under 10 years.It is suggested that ELISA may be used as a means for auxiliary diagnosis and seroepidemiological survey of filariasis.

EFFECTS OF PRAZIQUANTEL AND ARTEMETHER ON TEGUMENTAL SURFACE ANTIGENS OF DIFFERENT DEVELOPMENTAL STAGES OF SCHISTOSOMA JAPONICUM

1986, 4(4):  284-287. 

Asbtract ( )   PDF (1101KB) ( )  

Related Articles | Metrics

The tegumental surface antigens of different developmental stages of Schistosoma japonicum obtained from infected mice treated with a single oral dose of praziquantel 400mg/kg or artemether 600mg/kg were measured by indirected fluorescence assay. It was demonstrated that: (1) 4 hours after administration of praziquantel, the percentages of exposure of worm surface antigen were 90% in 2 hours' schistosomules (d0) and 25-42% in d21 to d42 schistosomules, but there was no effect on d3 to d14 old schistosomules; 16 hours later over 50% of adult worms isolated from the liver tissue showed the exposure of worm surface antigen. It is considered that the susceptibility of different developmental stages of Schistosoma japonicum to praziquantel is correlated With the exposure of worm surface antigen. (2) 1 to 3 days after administration of artemether, marked disturbance of parenchymal tissue and intestinal tubes were found in d7 schistosomules, but there was no effect on the exposure of worm surface antigen. However, 33-42% of female worms in d28 group showed worm surface antigen. It is believed that the mode of action of artemether on young and adult schistosomes is different.