| onchocerciasis prevalence in previously known foci in western uganda: results from a preliminary survey in kabarole district. | a prevalence survey of onchoceriasis was done in kabarole district, uganda, in 1990. the objective was to determine the prevalence of onchocerciasis among communities living in previously known foci. a total number of 1186 persons was included in the study. the infection rate among the communities studied ranged from 0% to 67%. the most frequent clinical signs and symptoms of onchocerciasis were: pruritus (80%), rough skin (46%), skin rash (30%), leopard skin (6%) and sclerosing keratitis (7%). ... | 1992 | 1519030 |
| freshwater crabs and simulium neavei in east africa. iii. morphological variation in potamonautes loveni (decapoda: potamidae). | potamonautes loveni (colosi) is the valid name for the species also described as p. granviki, p. harvardi and p. loveni longimerus, and incorrectly identified as p. berardi berardi. potamonautes jeanelli and p. idjwiensis may be allied to p. loveni, but are geographically separated and show sufficient morphological distinction not to be considered conspecific. potamonautes loveni occurs in the upper reaches of rivers on the highlands of western kenya and eastern uganda. its replacement by other ... | 1991 | 1888214 |
| review of vector control prior to the ocp. | it is a little over 60 years since blacklock, in an elegant study, demonstrated that in sierra leone human onchocerciasis was transmitted by a simulium fly. amazingly within 6 years of blacklock's discovery an attempt was made, mainly using environmental management, to control simulium in the chiapas focus of mexico, though this was not successful. later buckley was successful in eradicating simulium neavei from the small riana focus in kenya by clearing riverine forest. however, it was not unti ... | 1990 | 2198760 |
| onchocerciasis prevalence in tanzania. | prevalence of human onchocerciasis in tanzania is described. the prevalence is high in bwakira (63.6 per cent), mahenge (58.6 per cent) and ruvuma (31.9 per cent); and low in amani (22.4 per cent) foci when compared to that reported in 1970. the increase and decrease on the prevalence indicate that the disease transmission has been increasing and decreasing in the respective foci. it is speculated that bush clearing and deforestation in general, has positive effects on the transmission of onchoc ... | 1990 | 2225028 |
| population decline of simulium woodi and reduced onchocerciasis transmission at amani, tanzania, in relation to deforestation. | to investigate an apparent decline of the onchocerciasis vector simulium woodi, in the simulium neavei group, weekly 12-hour biting catches on man were carried out for 13 months near amani and compared with those obtained 22 years earlier. the results showed a marked fall in biting s. neavei s.l. females and supported earlier findings on the aquatic stages. the mean biting-catch in 1985/6 was only 13% of that in 1963/4 and comprised 91% s. woodi and 9% the more common, but largely zoophilic, sim ... | 1990 | 2378204 |
| a simple laboratory method for testing the susceptibility of larvae of the simulium neavei complex to insecticides. | certain species of the simulium neavei complex are important vectors of human onchocerciasis in africa. because of the association of the larvae of this complex with freshwater crabs, their insecticide susceptibility cannot be readily tested by any of the available methods. they are firmly attached to the crabs and can be removed only with difficulty and sometimes injury. the method described in this paper was developed, therefore, to obviate removal of the larvae from the crabs.larvae of s. nya ... | 1966 | 5298037 |
| a method of rearing simulium damnosum theobald (diptera; simuliidae) under artificial conditions. | the simuliidae have proved particularly difficult to maintain under artificial conditions, and have resisted all attempts at laboratory colonization. although a number of species have been successfully reared from egg to adult under laboratory conditions in certain northern countries, the problem of rearing african blackflies has been subjected to less intensive investigation. the development of suitable techniques for rearing and maintaining the vectors of human onchocerciasis in the laboratory ... | 1967 | 5301386 |
| onchocerciasis in kenya 9, 11 and 18 years after elimination of the vector. | elimination of the onchocerciasis vector simulium neavei through larvicidal operations in focal areas of kenya in 1946, 1953, and 1955 achieved complete interruption of transmission. since no treatment was administered to the infected population, the areas provided an opportunity for studying the natural course of the infection in man in the absence of reinfection, with particular emphasis on its average duration and the effect of duration of exposure to the infection. in a follow-up survey cond ... | 1967 | 5303323 |
| studies on the immature stages of the simulium neavei roubaud complex and their associated crabs in the eastern usambara mountains in tanzania. i. investigations in rivers and large streams. | | 1969 | 5392895 |
| studies on the immature stages of the simulium neavei roubaud complex and their associated crabs in the eastern usambara mountains in tanzania. ii. investigations in small heavily shaded streams. | | 1969 | 5392896 |
| the taxonomy of the east african river-crabs and their association with the simulium neavei complex. | | 1968 | 5689079 |
| a mid-arm interchange as a potential reproductive isolating mechanism in the medically important simulium neavei group (diptera: simuliidae). | the simulium neavei group is medically important as a vector of human onchocerciasis and is unique among blackflies because of the attachment to freshwater crabs during parts of the larval and pupal life cycle stages. detailed larval salivary gland polytene chromosome maps are presented for two taxa designated s. neavei amani form a and s. neavei amani form b, which are probably synonymous with the previously described morphospecies, s. nyasalandicum and s. woodi, respectively. simulium neavei a ... | 1994 | 7828843 |
| parasitological and clinical characterization of simulium neavei-transmitted onchocerciasis in western uganda. | in the forests of western uganda onchocerciasis is transmitted by simulium neavei s.s. since little is known about the infection transmitted by this vector, a survey was made in 1991 with special regard to adult persons of 15 years and older in the 13 villages of the parish kigoyera 40 km northeast of fort portal. 3268 (52%) of the 6271 registered inhabitants were examined clinically and parasitologically. the highest microfilaria (mf) densities were found on the buttocks, lower ones on the shou ... | 1993 | 8134773 |
| biochemical analysis, gene structure and localization of the 24 kda glutathione s-transferase from onchocerca volvulus. | survival of onchocerca volvulus, a pathogenic human filarial parasite, is likely to depend upon the detoxification activities of the glutathione s-transferases (gsts). the 24 kda o. volvulus gst, ovgst2, was expressed in a bacterial system and the recombinant protein was purified to homogeneity by affinity chromatography. specific activities of the recombinant ovgst2 (rovgst2) with a variety of substrates, and in the presence of inhibitors, were determined. with the universal substrate 1-chloro- ... | 1996 | 8885220 |
| strain differentiation of onchocerca volvulus from uganda using dna probes. | polymerase chain reaction (pcr) combined with non-radioactive dna hybridization was applied for the detection and characterization of a 150 bp tandem repeat of onchocerca volvulus. dna of worms from western uganda was amplified and then probed with a digoxygenin-labelled oligonucleotide, specific for the forest form of o. volvulus and compared to samples from various african countries. hybridization was only observed with pcr products from the forest in liberia, south-eastern ghana, benin and so ... | 1996 | 8935951 |
| reduced prevalence of onchocerciasis in uganda following either deforestation or vector control with ddt. | to determine the prevalence of onchocerciasis in western uganda following deforestation and vector control, three foci were re-examined 20 years after previous surveys. in the ruteete focus simulium neavei had apparently disappeared and the prevalence of onchocerciasis declined in adults from about 70% in 1971 to a standardised prevalence of 12% in 1992. an increase of population density together with extended deforestation was assumed as cause of this strong reduction. in bugoye, a s. damnosum ... | 1997 | 9337013 |
| pcr and dna hybridization indicate the absence of animal filariae from vectors of onchocerca volvulus in uganda. | in order to identify onchocerca volvulus larvae from vectors, dna of filaria larvae from dissected blackflies was isolated, and a 150-bp long tandemly repeated dna sequence (0-150), which occurs in many onchocerca species, was amplified using polymerase chain reaction (pcr). subsequently, the pcr product was blotted onto a nylon membrane and hybridized with dna probes specific for o. volvulus or onchocerca ochengi. filaria larvae from 395 infected simulium neavei were examined and 259 samples pr ... | 1997 | 9406774 |
| onchocerciasis control in uganda. | in 1990 a community-based programme of onchocerciasis control, involving the use of ivermectin, was introduced in uganda. the problems confronting it are discussed and suggestions are made for making it sustainable. | 1998 | 9652221 |
| rapid epidemiological mapping of onchocerciasis in areas of uganda where simulium neavei sl is the vector. | to test whether rapid epidemiological mapping of onchocerciasis (remo) was suitable for mapping of onchocerciasis in foci where s. neavei sl is the primary vector. | 1999 | 10520349 |
| dispersal range of simulium neavei in an onchocerciasis focus of western uganda. | the dispersal range of the vector simulium neavei roubaud (diptera: simuliidae) was investigated in an onchocerciasis focus in kabarole district, western uganda, adjacent to the itwara forest reserve, where the species breeds in phoretic association with the river crab potamonautes aloysiisabaudiae (nobili) (decapoda: potamonautidae). biting rates were highest at the edge of the forest, but blood-seeking flies were collected up to a distance of about 4 km from the forest. entomological data did ... | 2000 | 10759318 |
| validity of nodule palpation in a simulium neavei-transmitted onchocerciasis area in uganda. | the objective of this study was to evaluate the prevalence of palpable nodules as a rapid indicator for onchocerciasis endemicity in at-risk communities where simulium neavei s.s. is the transmitting vector. we used data collected from 13 villages in uganda to determine the validity of this rapid assessment method. the prevalence of palpable nodules was closely associated with the microfilarial prevalence (r2 = 0.603, p = 0.002), with the community filarial load (r2 = 0.620, p = 0.001) and with ... | 2002 | 12363057 |
| onchodermal skin disease in a hyperendemic onchocerciasis focus in western uganda. | to assess the degree of skin disease in simulium neavei s.s.-transmitted onchocerciasis, 72 patients infected with onchocerca volvulus in the kabarole district of uganda were studied. they were clinically and parasitologically evaluated. onchocercal skin lesions were determined using a modified murdoch skin assessment, and skin scores were calculated. the chronic skin score (4.0) was associated with age, and the acute skin score (8.5) was significantly higher in males. the burden of onchocercal ... | 2002 | 12479547 |
| the identification of infective filarial larvae in simuliidae. | although it is recognized that the presence of animal filariae can lead to confusion in the interpretation of infection rates in mosquito vectors of filariasis, the filariae found in man-biting simuliids are usually assumed to be onchocerca volvulus. the authors of this paper emphasize that it is unwise to calculate transmission indices from infection rates in man-biting simuliids unless there is confidence in the identification of the filarial larvae. in this respect they cite their observation ... | 1962 | 13938041 |
| freshwater crabs and simulium neavei in east africa. ii.further observations made during a second visit to east africa in february-april 1962 (the dry season). | | 1964 | 14183101 |
| the diet of freshwater crabs associated with simulium neavei in east africa. 3. the diet of potomonautes niloticus and of an unindentified crab species from mount elgon, uganda. | | 1965 | 14301693 |
| adverse reactions to ivermectin treatment in simulium neavei-transmitted onchocerciasis. | to assess adverse effects of ivermectin treatment in a simulium neavei-transmitted focus of onchocerciasis, a study was conducted with 1,246 patients infected with onchocerca volvulus in eight villages in western uganda. study participants were treated the first time with a single dose of 150 microg/kg of ivermectin. adverse reactions to ivermectin were determined through questioning and clinical examination during house-to-house visits to the participants within 48 hours after ivermectin treatm ... | 2003 | 14740878 |
| simulium neavei-transmitted onchocerciasis: hiv infection increases severity of onchocercal skin disease in a small sample of patients. | onchocercal skin disease was measured in 72 onchocerciasis patients from western uganda, where simulium neavei is the main transmitting vector of onchocerca volvulus. the onchocerciasis patients who were hiv-positive had a higher onchocercal skin score compared with those who were hiv-negative (33.7 vs. 19.4, p < 0.001). | 2003 | 15228250 |
| preliminary studies on the biting activity and transmission of onchocerca volvulus by simulium neavei (diptera: simuliidae) in kashoya-kitomi focus, western uganda. | to determine the biting activity and onchocerciasis transmission in kashoya-kitomi focus, western uganda. | 2004 | 15508338 |
| transmission of onchocerca volvulus and prospects for the elimination of its vector, the blackfly simulium neavei in the mpamba-nkusi focus in western uganda. | the transmission of onchocerca volvulus leuckart (spirudida: onchocercidae) and the prospects of simulium neavei roubaud (diptera: simuliidae) vector elimination through ground larviciding were investigated in the mpamba-nkusi focus, western uganda. transmission levels and the initiated vector elimination activities were assessed to supplement the ongoing ivermectin mass distribution programme. searches for breeding sites, adult fly catches, dissection of flies, river treatment with temephos (ab ... | 2006 | 16608493 |
| [african programme for onchocerciasis control (apoc): entomological aspects of onchocerca volvulus transmission by simulium neavei in the basin of sankuru (eastern kasai, democratic republic of congo)]. | as part of a study to evaluate the long-term impact of community-directed treatment with ivermectin (cdti), baseline entomological data on the transmission of onchocerciasis in the forest zone of the eastern kasai province were collected from july 1998 to january 1999. species of the simulium neavei complex were the only vectors found in the site during the study. nuisance activity was low with a mean biting rate of only 32.5 bites/man/day. the mean parturity rate was 29.4%, the mean rate of inf ... | 2007 | 17506270 |
| progress towards the elimination of onchocerciasis as a public-health problem in uganda: opportunities, challenges and the way forward. | the national onchocerciasis-control programme in uganda successfully eliminated simulium neavei s.s. from the itwara focus in 1997, by monthly ground spraying with larvicidal temophos (abate). since then, no vectors have been caught in the main itwara focus or two secondary foci in the same area. after 4 years of intervention, s. neavei s.s. has also been nearly eliminated from the mpamba-nkusi focus, and the elimination of this vector from two more foci (west nile and wambabya-rwamarongo) appea ... | 2007 | 17524247 |
| the elimination of the vector simulium neavei from the itwara onchocerciasis focus in uganda by ground larviciding. | the itwara focus of onchocerciasis covers an area of approximately 600 km(2) in western uganda about 20 km north of fort portal. the vector is simulium neavei, whose larvae and pupae live in a phoretic association on freshwater crabs. the phoretic host in the itwara focus is the crab potamonautes aloysiisabaudiae. before any onchocerciasis control, atps were estimated to reach between 4500 and 6500 infective larvae per person per year. s. neavei was found to be a very efficient vector with 40% o ... | 2009 | 19446785 |
| interruption of the transmission of onchocerca volvulus in the kashoya-kitomi focus, western uganda by long-term ivermectin treatment and elimination of the vector simulium neavei by larviciding. | uganda is the only country in sub-saharan africa whose onchocerciasis elimination programme extensively uses vector control and biannual treatment with ivermectin. the purpose of this study was to assess the impact of combined strategies on interrupting onchocerciasis transmission in the kashoya-kitomi focus. mass drug administration annually (13 years) followed by biannual treatments (6 years) and ground larviciding (36 cycles in 3 years) with temephos (abate(®), ec500) against simulium neavei ... | 2017 | 28034767 |
| transmission of onchocerca volvulus by simulium neavei in mount elgon focus of eastern uganda has been interrupted. | the study determined that simulium neavei-transmitted onchocerciasis in mount elgon onchocerciasis focus had been interrupted. annual mass treatment with ivermectin changed to two times per year along with vector elimination in 2007. then, baseline microfilaria (mf) prevalence data of 1994 in five sentinel communities were compared with follow-up data in 2005 and 2011. blood spots from 3,051 children obtained in 2009 were analyzed for onchocerca volvulus immunoglobulin g4 antibodies. fresh water ... | 2014 | 24686740 |
| the imaramagambo onchocerciasis focus in southwestern uganda: interruption of transmission after disappearance of the vector simulium neavei and its associated freshwater crabs. | it was not until early 1990s that, when the imaramagambo focus of southwest uganda was mapped, mass treatment with a single annual dose of ivermectin for onchocerciaisis control commenced. however, comprehensive investigations on its transmission were launched after a nationwide policy for onchocerciasis elimination in 2007. entomological surveys throughout the focus from 2007 to 2015 have yielded few or no freshwater crabs (potamonautes aloysiisabaudiae), which serve as the obligate phoretic ho ... | 2016 | 27215297 |
| the disappearance of onchocerciasis from the itwara focus, western uganda after elimination of the vector simulium neavei and 19 years of annual ivermectin treatments. | the itwara onchocerciasis focus is located around the itwara forest reserve in western uganda. in 1991, annual treatments with ivermectin started in the focus. they were supplemented in 1995 by the control of the vector simulium neavei, which was subsequently eliminated from the focus. the impact of the two interventions on the disease was assessed in 2010 by nodule palpations, examinations of skin snips by microscopy and pcr, and ov16 recombinant elisa. there was no evidence of any microfilaria ... | 2013 | 23458325 |
| the impact of ivermectin treatment alone and when in parallel with simulium neavei elimination on onchocerciasis in uganda. | the study was conducted in august 2002 in kigoyera parish in kyenjojo district, where ivermectin treatment had been the strategy to control onchocerciasis since 1991 and was later supplemented with simulium neavei control in 1995 and subsequent elimination; and in july 2003 in kicece parish in kamwenge district, where ivermectin treatment alone had been the strategy used to control onchocerciasis since 1991. our objective was to examine and compare the impact of ivermectin treatment alone and wh ... | 2004 | 15303993 |
| studies on the immature stages of the simulium neavei roubaud complex and their associated crabs in the eastern usambara mountains in tanzania. iv. observations on the crabs and their attached larvae under exceptionally dry conditions. | when exceptionally low rainfall resulted in the drying out of some 'permanent' streams containing the immature stages of simulium neavei complex species, the fate of the larvae and their associated crabs was investigated. both crabs and larvae survived under rocks, stones and boulders where some moisture persisted. such situations would be out of reach to insecticides applied to running water in the normal way. | 1978 | 666389 |
| studies on the immature stages of the simulium neavei roubaud complex and their associated crabs in the eastern usambara mountains in tanzania. iii. investigations on development and survival and their relevance to control. | | 1978 | 666388 |
| freshwater crabs and simulium neavei in east africa. i. preliminary observations made on the slopes of mount elgon in december 1961, and january, 1961. | | 1961 | 13717172 |
| the diet of freshwater crabs associated with simulium neavei in east africa. i. crabs from west and east uganda collected by the cambridge east african expedition, 1959. | | 1961 | 13785525 |
| the eradication of simulium neavei from kenya. | s. neavei, the vector of onchocerciasis, has been virtually eradicated from kenya by larviciding measures in which ddt was used. only a very small area remains infested and this is in the course of being treated by the uganda medical authorities as it is part of a much larger focus occurring in that country. an account is given of the various surveys which have been carried out during the last ten years in nyanza province, involving 15 000 square miles (about 40 000 km(2)), and survey techniques ... | 1958 | 13585062 |
| the problem of the simulium neavei complex. | | 1957 | 13472418 |
| [habitat of simulium neavei and simulium renauxi in preimaginal stages]. | | 1951 | 14819792 |
| phoretic association between afronurus and simulium species, and the discovery of the early stages of simulium neavei on freshwater crabs. | | 1950 | 14775661 |
| the eradication of simulium neavei, roubaud, from an onchocerciasis area in kenya colony. | | 1947 | 20287805 |