Table of Content

31 May 1984, Volume 2 Issue 2

Previous Issue    Next Issue

PROGRESS IN THE CONTROL OF AND RESEARCH IN FILARIASIS IN SHANDONG PROVINCE DURING THE PAST TEN YEARS

1984, 2(2):  66-72. 

Asbtract ( )   PDF (557KB) ( )  

Related Articles | Metrics

Bancroftian filariasis used to be highly prevalent in Shandong Province, involving 74 counties or cities. According to the estimation made in 1950s, there were about 2.5 millions of microfilariaemia cases and an equal number of patients with different clinical manifestations of filariasis. Mass survey and treatment of microfilaremia cases were carried out during the years from 1958 to 1960 in the most heavily endemic areas in the southern part of the province, resulting in a reduction of about 50% of the microfilarial rate. A province-wide control programme commenced in 1970 and about 59 million blood examinations were made. Altogether 1,813,596 microfilaremia cases were detected and treated with 2-3 regular courses of hetrazan (DEC). In 27 highly infected counties, the average microfilarial rate reduced from 1.3% to 0.09% after 2-7 mass blood surveys and selective treatment. Mass treatment with one regular course of DEC was given to all the people over 5 years of age in some communes and villages of 14 moderately infected counties where the microfilarial rate was still above 1% after 2-5 mass surveys and treatment. The average microfilarial rate was thus brought down to 0.17% as compared with 5.8% before control measures were taken. In 33 highly infected counties, DEC-medicated salt was given to a total population of about 23 million people for 4-6 months following 2-3 successive mass blood surveys and treatment. As a result, the average microfilarial rate has dropped from 12.4% in 1970 to 0.15% in 1980. Through these measures, the overall microfilarial rate in the province was reduced from 4.6% to 0.1% in 1983. In 74.8% of the 4,735 villages examined, no more microfilaremia cases could be found and the microfilarial rate in the remaining villages was less than 1%. The natural infection rate of Culex pipiens pollens, the main mosquito vector, has been reduced to almost zero, while in 1950s it was as high as 37.5-51.9%. Meanwhile, no new infection occurs in children born after the anti-filariasis campaign.It has been found that for blood survey and evaluation of control measures, the routine two-film method with 120 mm3 of blood taken from the earlobe is as reliable as the membrane filtration technique with 1 ml of venous blood but is much more simple and practicable. Patients with elephantiasis are effectively treated with intramuscular injections of aqueous extracts of mulberry leaves or audiofrequency electrotherapy in combination with bandage. Renal pelvic lavage with 1 % silver nitrate has been used for the treatment of chyluria with an immediate cure rate of 82.2% and 70% of cases remain symptomless 3 years after the treatment.For surveillance after the control of filariasis, the remaining microfilaremia cases could be traced by blood examination of the people in the houses or villages where naturally infected mosquitoes are discovered. This method may be used for identifying the residual source of infection instead of mass blood surveys.

EPIDEMIOLOGICAL SURVEY OF FILARIASIS IN FUJIAN PROVINCE

1984, 2(2):  73-77. 

Asbtract ( )   PDF (377KB) ( )  

Related Articles | Metrics

In Fujian, there are two species of human filariae, Wuchereria bancrofti and Brugia malayi, transmitted by Culex fatigans and Anopheles lesteri anthropophagus respectively and the microfilariae of both worms show well marked nocturnal periodicity. Remarkably different geographic distribution between the two worms is due to the different breeding behaviour of their vectors. The infection rate of B. malayi is often higher than that of W. bancrofti, and the infection rate of both parasites is higher in male. However, the microfilaria rate of B. malayi is not parallel with age, because the worm is liable to induce immunity. A good result could be obtained by raising the standard of living and control of breeding of the vector. Prevalence of the disease can be monitored by mosquito .survey. Though the source of infection of human filariasis in animal is not found, a lot of filaria species in animals especially in birds are present. It is necessary to further investigate so as to differentiate the species parasitizing animals from man.

ON THE CONTROL OF MALAYAN FILARIASIS IN MIAOXI COMMUNE, ZHEJIANG PROVINCE

1984, 2(2):  78-82. 

Asbtract ( )   PDF (374KB) ( )  

Related Articles | Metrics

Field control of malayan filariasis was carried out from 1964 to 1979 in Miaoxi Commune, Zhejiang Province. In the first stage from 1964 to 1967, the measures used were chemotherapy with DEC and residual spraying with DDT in human dwellings and animal sheds. Follow-up examination in 1968 showed thai the microfilaremia fate dropped from 20.21% to 0.7%, infective larvae were not found in mosquito vectors and the morbidity of filarial lymphangitis decreased gradually after control. When checked up 6 years later in 1974, it was found that the microfilaremia rate was 1.26%, 38.1% of the microfilarial positive cases were new immigrants, and some of the originally positive cases turned to be negative without treatment. These data indicated that the transmission of filariasis has been effectively controlled during this period. In the second stage (1974-1979), selective treatment with DEC was conducted. Thereafter the microfilarial rate was reduced from 1.26% to less than 0.2%. Since then, several blood surveys of the population in the commune showed that the microfilaremia rate was maintained at the low level throughout and no new infection among infants was found.

CHARACTERIZATION OF PLASMODIUM YOELII ANTIGENS BY MONOCLONAL ANTIBODIES. I. COMMON ANTIGENS BETWEEN ERYTHROCYTIC STAGES OF PLASMODIUM YOELII AND HUMAN MALARIA PARASITES

1984, 2(2):  83-87. 

Asbtract ( )   PDF (380KB) ( )  

Related Articles | Metrics

13 cell lines of hybrids secreting monoclonal antibodies (McAb) against erythrocytic stages of P. yoelii were established by fusing Sp 2/0 myeloma cells with spleen cells of BALB/c mice immunized with crude preparation of merozoil.es of the same malaria para- sue. me 13 McAbs ootamea can be classified according to IFA results into 4 groups: 1. against various developmental forms of P. yoelii in erythrocytes; 2. against late tro-phozoites and schizonts; 3. against schizonls and jnerozoites- and 4. against merozoites only. Five of the 13 McAbs showed cross immunofluorescence with human malaria parasites, in which 4 crossed with P, falciparum only.and 1 crossed with both P. falcipa-rum and P. vivax. It indicates that there are common antigens not only between rodent and human malaria parasites, but also between P. falciparum and P. vivax. The distri-; bution and quantity of the common antigens between different species of malaria parasite are not always the same. These differences should be carefully considered when hetero-genous malaria parasites are used for immunodiagnosis or for vaccination experiments. Immunofluorescence could not be observed on the surface of infected RBC when fresh infected RBC were used as target cells in indirect IFA test with McAbs.

STUDIES ON THE SEROLOGICAL DIAGNOSIS OF TOXOPLASMOSIS I. PURIFICATION OF TOXOPLASMA GONDII TACHYZOITES

1984, 2(2):  88-90. 

Asbtract ( )   PDF (216KB) ( )  

Related Articles | Metrics

A modification of the procedure described by Tsunematsu (1960) and Petrov (1974) for purification of Toxoplasma parasites ,was reported. Both pig and human strains of T. gondii maintained in mice by peritoneal inoculation were used. For parasite purification, peritoneal fluids were collected, digested with trypsin and filtered through a glass filter (G3) to remove host cells. Suspended parasites were freeze-dried for longterm preservation. Parasites and host cells were counted before and after digestion in some batches of infected mice, and Evan's blue staining was adopted for the examination of parasite vitality. Parasite yield, purity, viability as well as recovery rate were determined and compared in different lots.Application of this modified procedure resulted in an average parasite yield of (7.9±1.3) ×106 and (7.5±1.7) × 106 per mouse in pig and human strains respectively with no statistical difference (t = 0.55; p0.05). A high purity of 0.993±0.004 after treatment versus 0.668±0.18 before treatment was obtained, the noted difference being highly significant(t= 8.125; p0.01). The mean recovery rate as calculated from 4 lots has been 87.5% (t = 1.33; p0.05).

ON THE PATHOGENICITY OF ANGIOSTRONGYLUS CANTONENSIS IN LABORATORY ANIMALS

1984, 2(2):  91-94. 

Asbtract ( )   PDF (1487KB) ( )  

Related Articles | Metrics

Rats, mice and hamsters were infected by larvae of A. cantonensis, 52.1% of the fats died 24-35 days postinfection. The main cause of death was the damages in the cerebral blood vessels due to the migration of young adults from the brain to the lungs, which gave rise to severe hemorrhage. Besides, the worms themselves also directly dama-ged the brain tissues.From the 31st day postinfection, the reactions caused by the deposited eggs and the damages in the capillaries of alveoli caused by the moving larvae from the 36th day on led to the infiltration of inflammatory cells and the proliferations of fibrous tissue around.With the course of infection, pathologic changes extended gradually causing failure in respiratory function. That was the main cause of death in the later stage. Death might occur more rapidly if concurrent infections were present.Among rat, mouse and hamster, rat might be the ideal animal model for experimental infection with this worm.The distribution of worms in the CNS of the rats autopsied 24-35 days postinfection was: 52.5% in cerebrum, 19.3% in cerebellum, 11.7% in diencephalon and brain stem, 6.3% in spinal cord, 5.3% in cranial cavity, 4.3% in fissura cerebrocerebellaria and 0.6% in ventricle.

NOTES ON THE TWO FORMS OF ANOPHELES (CELLIA) MINIMUS THEOBALD, 1901 IN HAINAN ISLAND

1984, 2(2):  95-98. 

Asbtract ( )   PDF (294KB) ( )  

Related Articles | Metrics

The present paper reports on two forms of Anopheles (Cellia) minimus collected from-various parts of Hainan Island during 1964 and 1981-1982. Based upon a detailed study of the morphological characteristics of adult, larval and pupal stages, as well as of behaviors of susceptibility to DDT, the author is of the opinion that there are at the present two forms of Anopheles (Cellia) minimus, namely, A and B. The main characteristics of these two forms are given below.An. (C.) minimus form APalpi with apical one-third in dark ring, rarelyflavescent ring, or not three times hind bands. Firtt branch (vein m1+2) of 4th longitudinal veinwith 1-2 pale scales or rarely entirely dark. Single cone, anterior view of cirbarial armaturewith filament and bifurcated at the apex.Mental plate with 7 rarely 9 teeth in the larval stages.An. (C.) minimus form BPalpi with apical one-third in flavescent ring,rarely dark ring, or not three times hind bands. First branch (vein m1+2) of 4th longitudinal veinentirely dark. Single cone, anterior view of cirbarial armature,filament, narrow, without the fimbriated ends.or lateral spicules, and not bifurcated at the apex. Mental plate with 9 or 11 teeth in the larval stages. Based on behavior studies in the 50s, it was proved-that Are. (C.) minvmus was one of the chief malaria vectors in the mountain regions of Hainan Island and frequented human dwellings more than cattle sheds during the day, and this species preferred human blood. After repeated residual house sprayings with DDT in 1956, the density decreased sharply. The author designates this form as An. (C.) minimus form A.In recent years, observations made during the period May-July 1981 and March-April 1982 in Zhangsha and Huangnigou regions of Hainan Island showed that An. (C.) minimus could be excited by and escaped DDT spraying and fed chiefly on cattle, resting no more inside houses in the south-western part of Hainan Island. The author designates this form as An. (C.) minimus form B, which is a peri-wild species there.

SCANNING, TRANSMISSION AND FREEZE-ETCHING ELECTRON MICROSCOPY OF GIARDIA LAMBLIA CYSTS

1984, 2(2):  99-102. 

Asbtract ( )   PDF (2198KB) ( )  

Related Articles | Metrics

The cysts by SEM were ovoid shaped, approximately 9-10×6-7μm. The surface of cyst wall was rough instead of smooth. The cyst wall viewed with the freeze-etching technique was composed of many laminar layers of membrane. They were parallel to each other and numbered 10 or more.The thickness of cyst wall by TEM was 0.16-0.29μm. A space was seen between the parasite and the cyst wall, in which flagellar structures were cross sectioned. There were many vacuoles underlying the dorsal cell membrane of the parasite. But neither mitochondria nor endoplasmic reticulum and Golgi apparatus could be found except two different sizes of granules. Section through the regions of the nucleus shows two nuclei. The basal bodies were located near the midline line between the anterior poles of the nuclei, emerging anterior, posterior-lateral and caudal flagella. Parallel rows of micro-tubules with perpendicular ribbon-like structures were randomly distributed in the cyto-plasm.

OXYGEN ELECTRODE TECHNIQUE AND ITS APPLICATION IN METABOLIC STUDIES OF SCHISTOSOMA JAPONICUM

1984, 2(2):  103-106. 

Asbtract ( )   PDF (1107KB) ( )  

Related Articles | Metrics

This paper dealt with the application of oxygen electrode technique in the studies on metabolism of Schistoma japonicum. The rate of respiration, as well as the consumption of glucose of schistosomes, was satisfactorily determined by this method.Since the oxygen electrode technique is more convenient and more sensilive than the manometric method, it would be applicable to investigations on the aerobic metabolism of other parasites.

IN VITRO CULTURE OF INFECTIVE LARVAE OF PERIODIC BRUGIA MALAYI

1984, 2(2):  107-110. 

Asbtract ( )   PDF (1299KB) ( )  

Related Articles | Metrics

Essential -media tested were Earle, Earle +0.5% lactalbumin hydrolysate (Oxoid) and RPMI-1640. Baby jird testis and kidney tissue cell lines were used for culture. The most: favourable condition for the maintenance of the larvae in vitro was in a range of pH 6.4-7.5 and at temperatures of 36.5-37.5℃. The baby jird testis cell in growth medium RPMI-1640 was the best cell line tested with increases of 32.6% of the length and 36.8% of the width of the larvae taking place in 38 days cultivation. We observed successful moulting in both MT and MK cell lines. Brugia malayi began to moult on the tenth day. The survival of the larvae maintained on MK cell and MT cell were prolonged to 23 and 38 days respectively.

RADIOISOTOPIC LABELLING OF THIRD-STAGE LARVAE OF BRVGIA MALAYI IN ANOPHELES SINENSIS

1984, 2(2):  111-113. 

Asbtract ( )   PDF (227KB) ( )  

Related Articles | Metrics

The incorporation ire vivo of 35S-methionine, 3H-uridine and 32P-NaH2PO4 by the third-stage infective larvae in A, sinensis was investigated respectively by means of membranous feeding. The quantity of the three radioisotopes in these larvae were not equal. For example when 35S-methionine and 32P-NaH2PO4 were given to mosquitoes in almost equal quantity, the radioactivity was higher for the former than the latter in both the mosquitoes and larvae. The present study has provided an in vivo method for studying the biology of B. malayi larvae under the natural condition.

EFFECT OF MEBENDAZOLE ON EXPERIMENTAL ECHINOCOCCUS GRANULOSUS CYSTS IN MICE AS DEMONSTRATED BY ELECTRON MICROSCOPY

1984, 2(2):  114-116. 

Asbtract ( )   PDF (1395KB) ( )  

Related Articles | Metrics

The ultrastructural changes of the germinal membrane and the outer surface of experimental Echinococcus granulosus cysts treated with mebendazole for 300 days were observed. Cysts from mebendazole-treated mice were shown by transmission electron microscopy to have marked increase in vacuolization of the distal cytoplasm, dissolution of the minute spines, disturbance of organelles in their arrangement, disrupted aggregates of microtubules, increase in the size and number of lysosomes, decrease in the number of normal appearing Golgi bodies, increased density of the mitochondria, degranulation of the rough endo-plasmic reticulum. Crater-shaped pits, reduced or disappeared microtriches in the surface of the cysts were observed under scanning electron microscope. It seems clear that mebendazole has a profound effect on experimental Echinococcus granulosus cysts in mice. The changes in the structure and the function caused by mebendazole were discussed.

COMPARATIVE OBSERVATIOMS ON THE MORPHOLOGY OF DIFFERENT LARVAL STAGES OF SET ARIA DIGIT AT A AND BRUGIA MALAYI DEVELOPED IN ANOPHELES SINENSIS

1984, 2(2):  117-119. 

Asbtract ( )   PDF (1224KB) ( )  

Related Articles | Metrics

Sausage stage: The larva of B. malayi has two caudal nuclei, a small, nail-shaped tail and a small, conical head which distinguish it from that of S. digitate.Pre-infective stage: In contrast to S. digitata, B. malayi is small in size and has a shorter esophagus. Moreover, the posterior end of B. malayi is narrow and like a leaf of willow while that of S. digitata is blunt.Infective stage: B. malayi is characterized by three big tuberant papillae at the pos-terior end while the three papillae of S. digitata are small and rod-shaped. Anal ratio is greater in B. malayi (around 4) than in S. digitata (less than 3). Esophagus/total length ratio of the former is 1/3 while that of the latter 3/4.

OBSERVATIONS ON THE EFFICACY OF DIETHYLCARBAMAZINEMEDICATED SALT FOR CONTROLLING FILARIASIS

1984, 2(2):  120-122. 

Asbtract ( )   PDF (237KB) ( )  

Related Articles | Metrics

The effect of diethylcarbamazine (DEC)-medicated salt as a single measure on the) control of bancroftian filariasis in Zhecheng County, Henan Province in 1978 was reported. 9,422 subjects were selected from 8 production brigades from all parts of the county, having had blood examination before and after medication. The total dosage for each person was 9g of diethylcarbamazine. At the end of treatment the positive rate of mi-crofilaremia reduced from 6.25% to 0.2%. One year after, 7,485 subjects from 6 brigades were examined, the positive rate was 0.39%. 3 years later,?7 914 subjects from 8 brigades were examined, and the positive rate was 0.69%. The figures had come up to the parameter of filariasis control stipulated by the state (the positive rate of microfilaremia below 1% in all the production brigades). By the end of the medication, of 313 subjects with microfilaremia examined before, 97.1% of patients were cured, the density of mi-crofilariae was reduced from 11.96/60mm3 to 1.33/60mm3.