Acta Leidensia最新文献_第5页

Large scale ivermectin distribution and its epidemiological consequences. 伊维菌素的大规模分布及其流行病学后果。

Acta Leidensia Pub Date : 1990-01-01

J Remme, G De Sole, K Y Dadzie, E S Alley, R H Baker, J D Habbema, A P Plaisier, G J van Oortmarssen, E M Samba

{"title":"Large scale ivermectin distribution and its epidemiological consequences.","authors":"J Remme, G De Sole, K Y Dadzie, E S Alley, R H Baker, J D Habbema, A P Plaisier, G J van Oortmarssen, E M Samba","doi":"","DOIUrl":"","url":null,"abstract":"Community trials were started to address questions concerning the safety of ivermectin during large scale treatment, its potential for transmission control, its effect in preventing ocular onchocercal disease, its acceptability and the organization of large scale treatment. A summary is presented of the major, latest results on the short-term epidemiological impact of large scale ivermectin treatment, as observed in eight community trials undertaken in the Onchocerciasis Control Programme in West Africa (OCP). Ivermectin treatment resulted in a 96%-99% reduction in the mean load of microfilariae (mf) in the skin in treated patients. The subsequent mf-repopulation of the skin was faster than in the clinical trials and after 12 months the mean loads had returned to more than 40% of the pre-treatment load. Ocular mf loads were also greatly reduced and a post-treatment regression of early lesions of the anterior segment of the eye was observed. The transmission of Onchocerca volvulus was reduced by some 60% during the first year after treatment in one trial but no additional reduction was observed after the second treatment round. These results, and other recent research findings, have been used to quantify an epidemiological model for the transmission and control of onchocerciasis. Preliminary results of computer simulations of the predicted long-term epidemiological impact of large scale ivermectin treatment indicate that ivermectin treatment may play a very important role in disease control but that it is unlikely to become a practical tool for transmission control in endemic foci. Ivermectin treatment appears to be the most appropriate method for control of recrudescence of infection in an area where the parasite reservoir has been virtually eliminated by vector control, such as in the core area of the OCP.","PeriodicalId":7108,"journal":{"name":"Acta Leidensia","volume":"59 1-2","pages":"177-91"},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13351365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

New natural filarial parasites of nonhuman primates in Kenya: a potential use as laboratory model/s for onchocerciasis. 肯尼亚非人灵长类动物的新型天然丝状寄生虫:作为盘尾丝虫病实验室模型的潜在用途。

Acta Leidensia Pub Date : 1990-01-01

C N Wamae, F O Odongo

引用次数: 0

Resistance to reinfection of Simulium with onchocerca, and potential mechanisms for control. 盘尾丝虫病对盘尾丝虫病再感染的抗性及其可能的控制机制。

Acta Leidensia Pub Date : 1990-01-01

P J Ham, A J Baxter, P M Thomas, L Phillips, H Townson

引用次数: 0

Immunodiagnosis of onchocerciasis: circulating antigens and antibodies to recombinant peptides. 盘尾丝虫病的免疫诊断:循环抗原和重组肽抗体。

Acta Leidensia Pub Date : 1990-01-01

R M Maizels, J E Bradley, R Helm, M Karam

引用次数: 0

OCP intercountry collaboration. OCP国家间合作。

Acta Leidensia Pub Date : 1990-01-01

E M Samba

引用次数: 0

In vitro assessment of the activity of anthelmintic compounds on adults of Onchocerca volvulus. 驱虫化合物对盘尾盘尾虫成虫的体外活性评价。

Acta Leidensia Pub Date : 1990-01-01

G Strote, S Wieland, K Darge, J C Comley

{"title":"In vitro assessment of the activity of anthelmintic compounds on adults of Onchocerca volvulus.","authors":"G Strote, S Wieland, K Darge, J C Comley","doi":"","DOIUrl":"","url":null,"abstract":"The viability of adult Onchocerca volvulus and the effect of 12 known anthelmintic compounds on the parasites have been evaluated in an in vitro culture system. Three different parameters, a colorimetric assay, using NADH-dependent reduction of a tetrazolium salt to dark blue formazan by living adult worms, motility indices of male worms and lactate excretion of female worms were used to determine worm viability. The experiments showed that over a short term period of six days the viability of the worms did not decline significantly. The use of males isolated by dissection of whole nodules for the evaluation of drug effects in vitro is preferable to collagenase isolated worms. Mel W, milbemycin a and d, ivermectin, levamisole, CGP 6140 and, to a lesser extent, suramin immobilized male worms or significantly reduced the motility indices at a concentration of 10 microM. The tetrazolium reduction by male worms was not affected by levamisole, whereas the other active compounds demonstrated significant inhibitory effects. Diethylcarbamazine, mebendazole, flubendazole, metrifonate and CGP 20376 had no significant effect on male viability. Comparable activity was seen with the intact female worms isolated by collagenase digestion. Mel W, the milbemycins and ivermectin significantly inhibited tetrazolium reduction, whereas suramin and the other compounds had only slight or no inhibitory effects on female O. volvulus. Although one still has to aim at an improvement of the culture conditions, the in vitro test system using adult O. volvulus provides a basis for further research on potential antifilarial compounds.","PeriodicalId":7108,"journal":{"name":"Acta Leidensia","volume":"59 1-2","pages":"285-96"},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13525954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

In vitro antifilarial activity of some medicinal plants. 一些药用植物的体外抗丝活性。

Acta Leidensia Pub Date : 1990-01-01

J C Comley, V P Titanji, J F Ayafor, V K Singh

引用次数: 0

Prospective evaluation of onchocerciasis control strategies. 盘尾丝虫病防治策略的前瞻性评价。

Acta Leidensia Pub Date : 1990-01-01

J D Habbema, A P Plaisier, G J van Oortmarssen, J Remme

{"title":"Prospective evaluation of onchocerciasis control strategies.","authors":"J D Habbema, A P Plaisier, G J van Oortmarssen, J Remme","doi":"","DOIUrl":"","url":null,"abstract":"After more than 13 years of aerial larviciding, the Onchocerciasis Control Programme in West-Africa (OCP) is considering the future of its control activities. In the original OCP-area the prevalence of infection has been brought down to very low levels and cessation of larviciding is being contemplated. The introduction of ivermectin has broadened the spectrum of available control measures. Countries outside the OCP are also planning chemotherapy-based onchocerciasis control. The prediction of the epidemiological impact of the different control options is difficult in view of the many factors which affect the dynamics of a chronic infectious disease like onchocerciasis. We developed the computer simulation model ONCHOSIM, which takes these many factors and their interrelationships into account. The program has a broad spectrum of uses of which some examples are given. It is explained how the model is used to simulate endemic situations and epidemiological trends during vector control. These trends can be explained in terms of longevity of the parasite and other model parameters. Secondly, predictions are made about the risk of recrudescence after stopping larviciding. Finally, the possible role of ivermectin to control recrudescence after interruption of vector control and to reduce disease symptoms in an endemic situation is explored. The latter application is also important outside the OCP-area. This shows the usefulness of ONCHOSIM as a means for transferring the OCP-knowledge about onchocerciasis control to other countries. From our experience with ONCHOSIM, it is concluded that model based prospective evaluation of control measures is useful in synthesizing existing knowledge, in steering applied research, in interpreting the results of experimental studies, and last but not least, in aiding the policy-making process.","PeriodicalId":7108,"journal":{"name":"Acta Leidensia","volume":"59 1-2","pages":"387-98"},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13525963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Observations on the reproductive biology of Onchocerca volvulus. 盘尾丝虫生殖生物学的观察。

Acta Leidensia Pub Date : 1990-01-01

H Schulz-Key

{"title":"Observations on the reproductive biology of Onchocerca volvulus.","authors":"H Schulz-Key","doi":"","DOIUrl":"","url":null,"abstract":"This study compiles observations on the reproductive capacity of O. volvulus. Adult parasites enzymatically isolated from excised onchocercomata of untreated and chemotherapeutically treated patients, and from inhabitants living in areas with long vector control, were investigated to assess their fecundity. Changes of microfilaria development in utero and microfilaria release were assessed or estimated after treatment of patients with micro-filaricidal drugs that interfered with the development of intra-uterine stages. Intra-uterine production of microfilariae: After treatment of patients with ivermectin a daily development of 2500 to 4000 uterine microfilariae per female worm was observed. Actual output of microfilariae: Microfilariae left actively the female worms. The daily microfilaria release in vivo was 700 to 900 microfilariae, assessed after treatment of patients with mebendazole. In vitro most worms isolated from untreated patients shed between 500 to 1500 microfilariae per day.-The microfilarial load of 56 adult patients calculated from microfilarial skin counts was 12 million on the average. Taken for granted a mean life span of a microfilaria of 1.0 to 1.5 years, 22 to 47 female worms per patient would suffice to maintain this microfilarial load on a constant level. Excision of all palpable nodules showed a geometric mean of 15.9 female worms in these patients. It is suggested that factors intrinsic in the host and the adult worms partially operate together to regulate and maintain a stable microfilarial density.","PeriodicalId":7108,"journal":{"name":"Acta Leidensia","volume":"59 1-2","pages":"27-44"},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13526063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Vectors of onchocerciasis in the Thyolo Highlands and other onchocerciasis foci in Malawi. Thyolo高地盘尾丝虫病媒介和马拉维其他盘尾丝虫病疫源地。

Acta Leidensia Pub Date : 1990-01-01

M J Roberts

引用次数: 0