Table of Content

31 May 1986, Volume 4 Issue 2

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THE EXTENT OF RESISTANCE OF CHLOROQUINE RESISTANT FALC1PAHUM MALARIA AND THE GEOGRAPHIC DISTRIBUTION IN CHINA

1986, 4(2):  81-85. 

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This survey was conducted in cooperation with local institutions in 7 provinces and 1 autonomous region during 1979-1984.The in vitro microtechnique was conducted according to the instruction for use of the microtest kit supplied by WHO. WHO extended test in vivo was also used. The patients were kept in hospital for at least 8 days and followed up for 4 weeks.Of 90 cases from 4 counties in Hainan Island tested in vivo, 74 were resistant (82.2%). Of 155 cases from Yunnan, 115 were resistant(74.2%). Of 37 cases tested in Lingyun and Tiandong Counties of southwestern Guangxi, 32.4% were resistant. Of 31 cases tested in Wangmo, Libo and Shandu Counties of Southern Guizhou, 6.5% were resistant. All the 20 cases tested in Laian and Shucheng Counties of central Anhui were resistant. Of 52 cases tested from Henan, 5.8% were resistant. Of 2 cases tested in Chongan County of northern Fujian, one was resistant. No resistance was found in 8 cases tested in western Jiangsu.By using in vitro test, of 120 cases tested in Hainan Island, 94.2% showed resistance. Of 88 cases tested in Yunnan, 85.2% were resistant. Of 27 cases in Guangxi, 77.8% showed resistance. In Guizhou 36.4% of 33 cases were resistant. In Anhui all the 22 cases tested were resistant. Of 9 cases in Henan, 33.3% were resistant. Of 12 cases in Jiangsu, 41.7% were resistant. The drug resulted in 99.9% schizont inhibition (EC 99.9) at the level of 29.5×10-6M/L in Hainan Island, 85.7×10-6M/L in Yunnan, 13.8×10-6M/L in Guangxi, 3.1×10-6M/L in Guizhou, 2.2×10-6M/L in Henan, 18.6×10-6M/L in Anhui, 3.5×10-6M/L in Jiangsu.This study demonstrated that chloroquine resistance was present in Hainan Island and southern Yunnan and the extent of resistance was rather high. In southwestern Guangxi and central Anhui chloroquine resistance has also been detected but its degree is lower. In Henan, southern Guizhou and Jiangsu chloroquine resistance is incipient.

THE EFFECT OF HUMAN GLYCOPHORIN A AND SACCHARIDES ON INVASION OF HUMAN ERYTHROCYTE BY PLASMODIUM FALCIPARUM

1986, 4(2):  86-89. 

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The in vitro effect of different sugars and glcoproteins on the invasion of FCC-1/HN strain of P. falciparum merozoite into human erythrocyte is presented.1. Pure human glycophorin A inhibited invasion by 91% at 50μg/ml, and by 100% at 100μg/ml. Hen ovomucoid had 40% inhibitory effect at 100μg/ml.2. Human erythrocytes treated with sialidase or trypsin are less susceptible to merozoite invasion.3. D-glucosamine HC1, sialic and N-acetyl-D-glucosamine all had definitely inhibitory effect on merozoite invasion, however, no synergic effect was detected.4. Concanvalin A had no effect on merozoite invasion at 100μg/ml, while wheat germ agglutinin had a clearly inhibitory effect at the same concentration.

ENLARGED FIELD TRIALS OF BROMOACETAMIDE AGAINST ONCOMELANIA SNAILS

1986, 4(2):  90-92. 

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Foor snail-ridden fish ponds and their adjacent snail-ridden weedlands and irrigation ditches in Anhui and Jiangxi Provinces were selected for enlarged field trials of bromo acetamide. Results showed that the molluscicidal effects of bromoacetamide was satisfactory. When it was applied at the dosage of 1g/m2 along the pond banks and then shovelling down the turfs on the banks for immersion, or sprayed at 1g/m2 in the weedlands, or sprayed at 1g/m2 and then shovelling down the turfs in irrigation ditches, good molluscicidal effect was achieved. 100% of snail eggs were killed by spraying at 1g/m2. It did not kill fishes in the ponds, and did not affect the growth of rice seedlings when 10 ppm solution was used for irrigation in paddy fields.

APPLICATION OF SELF-MADE ALKALINE PHOSPHATASE FOR ELISA IN SCHISTOSOMIASIS JAPONICA

1986, 4(2):  93-95. 

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Self-made alkaline phosphatase (AKP) was prepared from pig intestine and then coupled with goat antihuman-IgG by one step glutaraldhyde method, the maximum titer of the conjugate being 1:6 400.Using Schistosoma japonicum soluble egg antigen as coating antigen, the positive rate of AKP conjugate was 100% in 54 proven patients with schistosomiasis japonica. The positive rates for sera from normal adults, pupils, patients of schistosomiasis, para gonimiasis, clonorchiasis, fascialopsiasis and filariasis were 2.1% (6/280), 0% (0/212), 96.5% (222/230), 2.80(1/35), 5.1%(5/98), 00(0/5) and 6.3%(5/79), respectively. The results showed that the AKP conjugate used in ELISA for schistosomiasis presented higher sensitivity and relative specificity.

A FIELD INVESTIGATION ON THE PROBABIUTY OF THE DISPERSION OF SCHISTOSOMA JAPONICUM EGGS TO ONCOMELANIA-INFESTED WATER BODIES IN 4 VILLIAGES OF WUXIAN COUNTY

1986, 4(2):  96-100. 

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A quantitative study on the probability of the dispersion of schistosome eggs into Oncomelania-infested water bodies was carried out during 1980-1982 in a plain region of schistosomiasis endemic area by field survey and simulated experiments. The results showed that the daily estimated number of eggs contaminating the snail-infested water bodies was approximately 12 671.58 in summer and 9 711.08 in other seasons, accounting for approximately 0.996 and 0.6996 of the total daily fecal egg output respectively in the 4 villiages investigated.Quantitative comparison of different ways of egg contamination showed that the washing of commodes is of greatest importance. Direct defecation of tattle into water bodies and fertilization of the fields nearby the streams are of secondary importance while the cleaning of nightsoil buckets and dippers and promiscuous feces are of minor significance. However, in summer, the overflow of the night soil jars nearby the water body plays an important role just next to the washing of commodes.

EXPERIMENTAL STUDIES ON THE BIOLOGICAL CHARACTERISTICS OF PLASMODIUMVIVAX IN SOUTH YUNNAN

1986, 4(2):  101-105. 

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From July 1983 to September 1984, experimental observations on healthy volunteers were carried out in the tropical and sub-tropical regions of Yunnan Province to determine the biological characteristics of Plasmodium vivax including prepatent period, incubation period, relapse potential and sensitivity to primaquine.39 persons devided into 5 groups were exposed to 1 to 10 mosquitoes infected with Plasmodium vivax obtained from different parts of south Yunnan Province. Among them 37 showed a prepatent period of 8-13 days, the average being 10.0±1.3 days, an incubation period of 12.2±1.9 days with a range of 10 to 17 days; 2 showed a long incubation period of 268 and 284 days, respectively.The relapse rate after treatment with chloroquine 1. 5g (base) alone or chloroquine combined with 14 days of primaquine was 95.2% and 0, respectively. In 75% of the participants the first relapse occurred after 228.8±45.6 days, followed by one or more subsequent relapses with much shorter intervening period of latency, most often ranging from 6 to 9 weeks. In 10% the first latent period was short, being 72±20 days, followed by a long second latent period (136±12 days). These relapse patterns are similar to that classified as the "temperate zone" type. In the second group which had been subdivided into two subgroups of 3 patients each the features of either Type I or II were observed. Namely, the pattern in the first subgroup had the characteristics of the Chesson-like type with no long period of latency between primary attack and subsequent relapses, and in the second subgroup the pattern presented the characteristics of temperate zone, which had a long period of first latency.On the basis of their life patterns, it could be concluded that: (1) The long incuba tion period is not confined to temperate zone strain; (2) The vivax malaria observed in the study areas briefly fell into the "temperate zone" category.

ON THE FACTORS INFLUENCING THE CRYOPRESERVATION OF BRVGIA MALAYI MICROFILARIAE

1986, 4(2):  106-108. 

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This paper describes the cryopreservation of microfilariae of Brugia malayi for 48 tours by means of the cryogenic technique of Ham's two-step cooling schedule. The experiments suggested that the viability of the microfilariae, as illustrated by motility (%), normal appearance (%), and mean activity index (maximum = 4) was lower in the frozen groups than in the unfrozen controls, whether or not newborn calf serum had been added. The viability of the microfilariae treated by cryogenic technique with newborn calf serum was higher than that without. We observed that the viability of microfilariae was greatly decreased with the increase of DMSO concentration within 5-30%. The results showed that the optimal cryopreservation solution was pH 7.0-7.2 Tyrode's solution containing 5% DMSO as cryoprotectant and 20% newborn calf serum as well as 200 units/ml of penicillin and streptomycin each and maximum viability occurred after cooling at the rate of 1℃ per minute to -17℃, followed by rapid plunge into liquid nitrogen.

EFFECT OF EOSINOPHILS ON THE GROWTH AND DEVELOPMENT OF PAGUMOGONIMUS SKRJABINI IN RATS

1986, 4(2):  109-112. 

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(5.97±0.54)×107 eosinophils per rat were obtained from the peritoneal fluid of P. skrjabini-infected rats forty eight hours after the injection of adult worm extract. Anti-eosinophil serum (AES) was prepared from rabbits immunized by injecting 2×107 rat-eosinophils intravenously four times a month and then bled.Rats were divided into four groups. Animals in the experimental group were administered 1ml AES/100g i. p. every other day for four times. The other three groups of animals were given cortison (Cor), normal rabbit serum (NRS) and normal saline (NS), respectively. Each rat was given 30 cysts of P. skrjabini orally 1 week later. Peripheral blood eosinophils were found to be markedly depressed in AES treated rats. In contrast, eosinophils in NRS-or NS-treated groups increased significantly. The average number and size of worms obtained from the four groups are not significantly different. However, the reproductive systems of the worms in AES-treated rats were well developed, while those in NRS-and NS-treated rats developed poorly, the difference being statistically significant (P0.001).The results suggested that eosinophils might be of importance in inhibiting the maturation of Pagumogonimus skrjabini.

THE OCCURRENCE OF MERMITHID NEMATODE ROMANOMERMIS JINGDEENSIS IN PUPAE AND ADULTS OF ANOPHELES SINENSIS

1986, 4(2):  113-115. 

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Pupal and adult stages of A. sinensis could be infected with R. jingdeensis when 4th-Instar larvae were exposed to preparasites, and the ratio of nematodes in late 4th-instar carried into adult mosquitoes was much higher than that of nematodes in early 4th-instar. This was the first time that the mermithid parasite was found within the pupal and adult stages of anopheline mosquitoes. Another experiment showed that the nematodes arrested ovarian development in most females, only one female was found with completed ovarian development, so the possibility could not be excluded that the infected adults might serve as a vehicle to spread nematodes to other breeding sites. Infectedmosquitoes appeared to have mating activity because sperms were found in the sperma-theca of an infected adult female. The pupae were insusceptible to prepasraites when they were directly exposed to the nematode.

CULTIVATION OF TOXOPLASMA GONDII IN VITRO

1986, 4(2):  116-117. 

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In this paper the authors describe an in vitro cultivation method for recovery of Toxoplasma gondii tropohozoites in which pig kidney cells were used. The result showed that when 2×106 trophozoites were inoculated in 199-Hanks' culture medium, the number of trophozoites multiplied was 20-50 times greater in six to seven days.It is suggested that this proved to be an economical method for collecting Toxoplama trophozoites as antigen materials.

ELECTRON MICROSCOPIC OBSERVATION ON CYSTICERCUS CELLULOSAE TREATED WITH PYQUITON IN VITRO

1986, 4(2):  118-119. 

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The changes of Cysticercus cellulosae treated in vitro with pyquiton were studied under the transmission and scanning electron microscopes. They were also compared with normal controls. The detachment and adhesion of microtriches on the neck of their scolex were demonstrated under scanning electron microscope and numerous vesicular structures were seen on the surface of their neck. The vacuolization of their tegument, swelling of muscles and finally, destruction of their tissues were seen under the transmission electron microscope. It is indicated that pyquiton has a direct destructive effect on the parasite.

OBSERVATION ON THE EFFECT OF MANDELIC AMIDE ON TRICHOMONAS VAGINALIS BY TRANSMISSION ELECTRON MICROSCOPY

1986, 4(2):  120-122. 

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This article reports on the following structural changes of Trichomonas vaginalis under the action of mandelic amide in vitro observed by TEM: 1. cytoplasmic membrane was destroyed; 2. nuclear membrane of the cell disappeared; 3. granular endoplasmic reticulum and free ribosome in the cytoplasme all disappeared; 4. chromatic granules highly electron-dense, and their membrane disappeared. The results suggested that these structural changes might be attributable to the effect of mandelic amide.

EXPERIMENTAL STUDIES ON THE INFESTATION OF PIGS WITH PARAGONIMVS WESTERMANI

1986, 4(2):  123-125. 

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Eight pigs were experimentally infested with metacercariae, excysted adolescariae and adult worms of P. westermani respectively with dogs as controls. Autopsy was performed at certain intervals varying from 16 to 107 days postinfection. The results were as fol lows: (1) Excysted adolescariae removed from the muscle of infected pigs were only slightly bigger than the metacercariae; (2) P. westermani adult worms separately inoculated into the subcutaneous tissue and the peritoneal cavity of the infected pigs died or atrophied; (3) Some of the adult worms inoculated into the pleural cavities of the pigs were found in the lungs, forming cysts 45 days later. From the above results, the authors suggested that the pig from Wenzhou might be considered as the paratenic host rather than the final host of P. westermani.

FURTHER STUDIES ON THE RELAPSE OF PLASMODIUM CYNOMOLGI IN RHESUS MONKEYS

1986, 4(2):  126-128. 

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10 rhesus monkeys which had been exposed each to the bite of 98-169 Anopheles dims with heavy gland infection of P. cynomolgi were observed for the incidence and frequency of relapses within 6 months after infection.The prepatent periods were 7 or 8 days. Whenever parasitemia was overt, a dose of 20mg/kg of chloroquine base was given orally per day for 3 days. 7 out of 10 monkeys suffered 1-4 relapses. The incidence was similar to that (62.5%) obtained by inoculating isolated sporozoites (0.28-6.5 million) of the same species into rhesus monkeys as reported in our previous paper.