Table of Content

31 May 1987, Volume 5 Issue 2

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LONGITUDINAL SURVEILLANCE IN AREAS WITH BANCROFTIAN FILARIASIS VIRTUALLY ERADICATED IN GUIZHOU

1987, 5(2):  81-84. 

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A longitudinal surveillance was carried out in Shijing Township, Zhengan County and Longpan Village, Dejiang County, where bancroftian filariasis had been virtually eradicated and control measures no longer adopted.The results indicated that the microfilaria rate (MR) in Shijing Township was further reduced from 0.15% in 1980 to 0.07, 0.04 and 0.05% in 1981, 1983 and 1985, the average Mf density in positive persons was 6.5, 11.5 and 3.5/120mm3 respectively. Since 1981, no new infections were found. The positive rate of IFAT was reduced from 8.9% in 1980 to 3.1 and 1.2% respectively after 3 and 5 years. From 1982-1985, annual dissection of Culex pipiens fatigans failed to find filaria larval infection. These results suggest that filariasis transmission in this area has been interrupted (Table 1).Concurrently another follow-up observation on the filariasis control was conducted in Longpan Village where microfilarial rate has dropped from 0.8% in 1975 to 0.48% in 1985, but due to the presence of a case with high microfilaremia density (72/120 mm3), the natural infection rate of vector mosquitoes collected from this household was as high as 20.6%, bearing with infective larvae. Blood examination discovered one new patient. The positive rate of IF AT was 23.5%. These findings showed that the tran-smission of filariasis in this area is continuing.The authors deemed that when MR was reduced to below 0.5% in an area, control measures might be omitted while surveillance should be strengthened.

MALARIAL CONTROL MEASURES AND THEIR EFFECTIVENESSIN BASIC ERADICATION OF MALARIA IN LARGE AREA IN GUIZHOU

1987, 5(2):  85-88. 

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This paper reports on the malaria control measures and their effectiveness in Kaili county and other 11 counties, i. e. Majiang, Huangping, Zhengyuan, Shibing, Tianzhu, Jing-ping, Duyun, Wengan, Fuquan, Longli and Guiding situated in the middle and southeast of Guizhou, with an area of 21 570 km2 and a population of 2.97 million.Prior to antimalarial campaign (1955), the reported malaria cases amounted to 149 605 and the morbidity was 958 per ten thousand. Malaria control programme has been carried out in large scale since 1958 and the morbidity dropped to 5 per ten thousand in 1965. From 1981 onwards, malaria management and surveillance in the final stage of malaria eradication have been undertaken in all the counties and the malaria situation has been greatly changed.At present, leading groups of malaria management and surveillance at county, district and village levels are well organized and the antimalarial infrastructure is well developed. The system of malaria case detection, presumptive treatment, radical treatment, follow-up of malaria case/foci has been set up. From 1981 to 1984, the malarial morbidity was between 0.2-0.03 per ten thousand, the annual blood examination rate was between 7.4-10.2%.

ESTIMATION OF SOME ENTOMOLOGICAL PARAMETERS IN RELATION TO THE

1987, 5(2):  89-92. 

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In order to analyse the transmission dynamics of bancroftian filariasis, an investigation of some entomological parameters was carried out in Queshan County, Henan Province. The results were as follows:1.From July to September during 1982-1984 the average of man-biting rate of Culex pipiens pallens in residents sleeping outdoors and in those using mosquito nets were 108 and 45/per person per night, respectively (Table 1).2.A total of 1851 Culex pipiens pallens were dissected, the parous rate was 0.386.3.The duration for the mosquito from blood-taking to oviposition was 4.5 days on average and the first gonotrophic cycle was around 5.5 days.4.The daily survival rate of the mosquito calculated was 84.1%.5.Eleven days were needed for the development from microfilaria to infective larva in mosquito.6.The proportion of infective mosquito calculated by the daily survival rate and the days needed for development of mature filaria larvae in mosquito was 0.149 which, was very close to 0.153 obtained in the field observation.7.The human blood index of Culex pipiens pallens was 0.81.

STUDIES ON INDIRECT FLUORESCENT ANTIBODY TEST FOR DIAGNOSIS AND EPIDEMIOLOGICAL INVESTIGATION OF FILARIASIS

1987, 5(2):  93-95. 

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Indirect fluorescent antibody test (IFAT) using frozen sections of Brugia malayi adult worms as antigen was employed in the diagnosis and epidemiological investigation of human filariasis. Sera were collected from 704 cases with bancroftian or malayan microfilaremia. the positive rate was 92.8-99.1%. Of 150 healthy people from non-endemic areas, only one showed a positive reaction (false positive rate 0.7%) (Table 1). This technique proved to be highly sensitive and specific for the diagnosis of filariasis and the antigen is easy to prepare. It might be used in sero-epidemiological investigation for the assessment of filariasis control.

STUDIES ON IMMUNO-DIAGNOSIS FOR CYSTICERCOSIS CELLVLOSAE. 1. ELECTROPHORETIC ANALYSIS OF PROTEIN AND ANTIGENIC PREPARATION OF CYSTICERCVS CELLVLOSAE

1987, 5(2):  96-100. 

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The present paper reports on the electrophoretic patterns of antigens prepared from the cyst fluid and the scolex-cyst wall complex of C. cellulosae. The band model in PAGE and SDS-PAGE and the method for detecting the immunological antigens against rabbits, hyperimmune sera were investigated. It was found that the antigenic composition of C. cellulosae was highly complex. In scolex-cyst wall complex, we found 13 bands in PAGE and 22 bands in SDS-PAGE stained by Coomassie brilliant blue R-250, and 11 IE components against corresponding rabbit's hyperimmune sera. The cyst fluid showed 10 bands in PAGE and 16 bands in SDS-PAGE stained by Coomassie brilliant blue R-2SO, one band stained by PAS and another by Sudan black B. 14 IE antigenic components in cyst fluid were demonstrated. The cyst fluid is rich in protein, glycopro-tein and lipoprotein, and contains at least one major serologically antigenic component. Both the cyst fluid and scolex-cyst wall complexes contained heat-resistant antigens, and .shared 3 common components.

ESTABLISHMENT OF FCC102/JS STRAIN OF PLASMODIUM FALCIPARUM

1987, 5(2):  101-103. 

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A new strain of Plasmodium falciparum was isolated from Jiangsu, China and coded FCC102/JS in continuous cultivation for a period of 52 days by Trager-Jensen's Candle Jar method with gametocytes found over the whole period (Table 1). This strain differed distinctly in growth rates from FCC1/HN and FCC4/HN isolated from Hainan Island. The mean multiplication rate in 96 hrs of FCC102/JS was 3.83 ±1.13,while that of FCC1/BN and FCC4/HN was 10.03 ±0.88 and 9.85 ±0.38,respectively. The results of 48 hrs in vitro microtechnique showed that FCC102/JS was sensitive to chloroquine with a mean IC50 of 42.03(28.51-61.95) nM (Table 2). It was suggested that there may be some biological differences between FCC102/JS strain and FCC1/HN as well as between FCC102/JS and FCC4/HN strain.

GEOGRAPHICAL DISTRIBUTION OF ANOPHELES LESTERI ANTHROPOPHAGUS AND ITS ROLE IN MALARIA TRANSMISSION IN GUANGXI

1987, 5(2):  104-106. 

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This article reports on the role of Anopheles lesteri anthropophagus in malaria transmission and its distribution in Guangxi Autonomous Region from 1983 to 1986. A. lesteri anthropophagus was found in 251 pilot sites of 19 counties in a survey on 524 pilot sites of 21 counties. It was the predominant species in Secun Village of Huang-Jiang county and Ziqiu village of Loucheng county (55.1% and 51.5% of the total anopheline population).The positive sporozoite rate of A; lesteri anthropophagus was 0.3%(5/1585) and 0.3% (1/400) in Huangjiang county and Loucheng county. Its positive sporozoite rate and positive oocyst rate were 1.9%(1/54) and 0.4%(1/257) in Baibao brigade of Shan-gsi county respectively.The human blood indices (HBI) of A. lesteri anthropophagus, A. sinensis and A. minimus were 0.291-0.633, 0.0597-0.119 and 0.155, respectively (Table).The results show that A. lesteri anthpropohagus is the chief vector of malaria in the north of Guangxi, and plays an important role in the transmission of malaria there.

OBSERVATIONS ON THE CIDAL EFFECT OF THREE KINDS OF SYNTHETIC PYRETHROID CHALKS ON BEDBUGS

1987, 5(2):  107-109. 

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Insecticide-chalks impregnated with either one of the three kinds of synthetic pyre-throids (deltamethrin, permethrin and cypermethrin) have been used to kill bedbugs (Cimex lectularius) in our laboratory.The results showed that three kinds of insecticidechalks are all effective, cypermethrin being the best one. After contacting with the paper spread with insecticide-chalk for one minute, bedbugs were all killed in 24 hours (Table 1). In simulation experiments,after having crossed over a 0.6cm-barrier on paper traced with 18mg/g cypermethrin-chalk, 97.5% of bedbugs were killed in 24 hours, 100% in six days, whereas 100% of bedbugs were killed in 24 hours over a 1.2-1.8ern-barrier on traced paper (Table 2). The effectiveness of cypermethrin-chalk can last for more than 140 days, suggesting that it is highly effective against bedbugs. Besides, cypermethrin-chalk has no unpleasant ordour and is convenient for use.

EFFECTS OF CYCLOLEUCINE ON THE GROWTH AND METABOLISM OF MALARIA PARASITES

1987, 5(2):  110-113. 

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When cycloleucine(80mg/kg) was given to mice infected with Plasmoaium cergnei for five days, it completely suppressed the growth of parasites. The growth of P. falci-parum in vitro in cycloleucine (1.5×10-2M) treated group was considerably arrested at the trophozoite stage, after 72 hours incubation. Abnormal parasites constituted about 90% of the total parasite population.After incubating for 30 hours 1.5×10-2M cycloleucine inhibited the total incorporation of 3H-hypoxanthine by 52-58%, whereas it exhibited a stronger inhibition by 79% in the incorpoation of this compound into nucleic acids.Cycloleucine also inhibited the total incorporation of 14C-methionine by 30% and the synthesis of spermidine by 50%, of which the aminopropyl group was derived from 14C-methionine.The observed effects of cycloleucine on malaria parasites led us to suggest that cyloleucine not only blocked the incorporation of hypoxanthine and methionine but also influenced the metabolism of S-adenosyl-methionine.

INDIRECT FLUORESCENT ANTIBODY TEST WITH TWO DIFFERENT ANTIGENS IN A REPEATED CROSS-SECTIONAL SURVEY OF MALARIA

1987, 5(2):  118-120. 

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A 2-year repeated cross-sectional survey was carried out using Plasmodium falciparum and P. cynomolgi antigens in IFA technique in three different malaria endemic areas of Anhui Province where different antimalaria measures were adopted during 1983-1984 (Table 1). For comparison, a longitudinal survey was done simultaneously. The identical results of the two surveys suggest that both could be used to estimate the degree of endemicity and variation of falciparum and vivax malaria and to assess the effects of antimalaria measures.

HISTOLOGICAL OBSERVATIOIS ON CUTANEOUS LEISHMANIASIS PRODUCED BY TWO SPECIES OF LEISHMANIA

1987, 5(2):  121-123. 

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Four BALB/c mice and two CFW mice were inoculated subcutaneously with proma-stigotes of Leishmania gerbilli 3.0 ×106/mouse and Leishmania mexicana amazonensis 3.2 × 106/mouse, respectively.1.5 and 5 months after inoculation, the mice were killed for histopathological examination. Leishmania gerbilli in BALB/c mice was confined mainly to the center of phagocytes. On the contrary, Leishmania mexicana amazonensis in CFW mice was chiefly distributed on the edge of phagocytes.Nearly all the cutaneous tissue of the inoculated mice showed congestion, edema and inflammatory cell infiltration, but the average number of neutrophils and fibroblasts in the foci of BALB/c mice was greater than that in the CFW mice, while the average number of lymphocytes in the foci of CFW mice was greater than that in the BALB/c mice (Table 1 and Plates 1-4).

SCANNING ELECTRON MICROSCOPIC OBSERVATION ON THE DAUGHTER REDIA OF PARAGONIMUS WESTERMANI

1987, 5(2):  124-126. 

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This paper is the first report on the ultrastructure of daughter redia of Paragonimus westermani in China. The specimens were obtained from naturally infected Semisulco-spira libertina collected from Daye, Hubei Province.The daughter redia of P. westermani is elongated or in the shape of slightly bent cylinder. The outer surface of tegument is folded in the form of annular ridges and troughs. The body surface is frequently contoured to show the outline of developing cercariae inside. At the anterior end, the daughter redia looks conical. The mouth is at the tip of the anterior end and surrounded by a thinner ring of tegument forming a distinct lip. A short distance behind the mouth there was a "birth pore" which is sur-rounded by microvillous projections, vesicles and pits.On the surface of the daughter redia, many microvillous projections are observed and numerous tiny vesicles are attached to the tegument, thus greatly increasing the absor-ption surface area of the tegument and serving in the transport of nutrients through the microvillous projections from the outer surface into the tegument.

EFFECTS OF SCHISTOSOME-DERIVED METABOLIC PRODUCTS ON THE PROLIFERATIVE RESPONSE IN MICE INFECTED WITH SCHISTOSOMA JAPONICUM

1987, 5(2):  127-129. 

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The effects in vitro of schistosomula- and adult worm-derived metabolic products on the proliferative response of splenic lymphocytes to soluble egg antigen (SEA) in mice infected with S. japonicum was studied. The results showed that the proliferative response of splenic lymphocytes to SEA in infected mice was enhanced when schistosomula-derived metabolic products were added to the in vitro culture of splenic lymphocytes and SEA (Fig. 1). However, adult worm-derived metabolic products had inhibitory effects on the proliferative response in the above mentioned culture (Fig. 2). It was suggested that there were certain regulative effects of schistosome-derived metabolic products on the proliferative response in mice infected with S. japonicum in vitro, and these regulative effects varied with the factors released by different developmental stages of schistosomes.

IN VITRO INHIBITORY EFFECT OF INTERFERON ON SIMULATED GRANULOMA FORMATION BY EGGS OF SCHISTOSOMA MANSONI

1987, 5(2):  130-132. 

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The effect of gamma interferon on the simulated granuloma formation induced by the eggs of Schistosoma mansoni was observed using a model of SEA-polyacrylamide beads and mouse spleen cells in vitro. The results showed that interferon at the concentration of 0.1~10U/ml could not affect significantly the granulomatous response of the spleen cells of unimmunized mice (Table 1); but at the concentration of 10-100U/ml it could inhibit significantly the response of the spleen cells of immunized mice (Table 2). The mechanism of the inhibition is probably due to the suppression of T helpers in the present study.

CONVERSION OF SCHISTOSOMA JAPONICUM CERCARIAE TO SCHISTOSOMULA UNDER THE ACTION OF PRAZIQUANTEL

1987, 5(2):  133-135. 

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When Schistosoma japonicum cercariae were exposed to praziquantel 1 or 10 fig/ml in dechlorinated tap water, the tail of cercariae was separated from the body within 1 minute or more. The cercarial bodies became swollen and dead within 2-4h. If the cercariae were exposed to praziquantel for O.Sh and then transferred to serum-HBS, the tail-less cercariae promptly resumed their normal movement. They were characterized by water sensitivity, depletion of penetration gland contents, complement insensitivity, negative "Cercarien-Hiillen Reaktion" and loss of normal cercarial shape (Table 1, Plates 1-6). These tailless cercariae induced by praziquantel satisfied the criteria of postpenetration schistosomula.

HOST TRANSFER OF PARAGONIMUS WESTERMANI AMONG MICE AND ITS DEVELOPMENTAL CHANGES

1987, 5(2):  136-138. 

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This paper deals with the development of Paragonimus westermani (Kerbert, 1878) in mice inoculated with metacercariae or stunted adolescariae. In metacercaria-inoculated mice, all worms were stunted all the time, but when the stunted worms were orally transferred Into mice, some (8.4%) grew so fast that their rudimentory reproductive organs appeared and their length was over 3 times that of stunted worms 3 weeks post inoculation; while 91.6% of the recovered adolescariae were still stunted and morphologically similar to excysted metacercaiae. When the stunted worms were repeatedly transferred through mice by oral route 8.2-10.1% of the recovered worms developed quickly, while the remainder was still stunted (Table 1).After 3 transfers in mice, the stunted worms were still able to infect dogs orally and reach maturity (Table 2).On the basis of the study, it is postulated that cannibalism and preying among wild rats would enable P. westermani to be transferred among rodent paratenic hosts.

DETERMINATION OF PORTAL BLOOD FLOW WITH ELECTRO-MAGNETIC FLOWMETER IN SCHISTOSOME-INFECTED RABBITS

1987, 5(2):  139-140. 

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The present paper reports on the determination of portal blood flow in schistosome-infected rabbits and normal rabbits by the use of electro-magnetic flowmeter. It is found that the values of portal blood flow in 10 schistosome-infected rabbits and 8 normal rabbits were 34.4 ±7.3ml/min and 66.9 ±5.5ml/min respectively,the difference being statistically signifi-cant. This method of determination is direct and accurate.

CLINICAL OBSERVATION ON TREATMENT OF 300 CASES OF CYSTICERCOSIS WITH ALBENDAZOLE

1987, 5(2):  141-143. 

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Three hundred cases of cysticercosis cellulosae (175 cerebral, 125 subcutaneous-muscular) were treated orally with albendazole, 15-20 mg/kg/day for a 10-day course. Every patient received 3 treatment courses with an interval of two or three weeks.After 6-12 months, the therapeutic effect of albendazole was estimated in subcutaneous-muscular cases by the number of subcutaneous nodules, the activity and the morphological change of larvae in cerebral cases by the neuropsychic symptoms, CSF changes, CT findings and the degrees of recovery in physical and mental ability.The result showed that in the cases of subcutaneous-muscular cysticercosis the cure rate was 64.0%;the rate of significant effect, 25.6%; and that of clinical improvement, 10.4%; while in the cases of cerebral cysticercosis the rates were 40.6, 44.0 and 15.4%, respectively.