| [toxicity of bacillus thuringiensis var. israelensis for simulium larvae, vectors of onchocerciasis]. | on field trials in infested streams, the primary powder r 153-78 made of b. thuringiensis var. israelensis with a potency of 3,000 i.t.u. aedes aegypti/milligramme is very toxic for blackfly larvae, especially for simulium damnosum s.l. larvae. the lethal concentration 100, in 24 h. is 0.2 x 10(-6) for a 10 min. treatment. this high toxicity, specific for diptera larvae such as mosquitoes and blackflies, is related to the special characteristic of the bacterial crystal protein which has a clear ... | 1979 | 118818 |
| age-related differences in parasitosis may indicate acquired immunity against microfilariae in cattle naturally infected with onchocerca ochengi. | onchocerca ochengi is a common parasite of cattle in savanna areas of west africa and its adult stages inhabit intradermal nodules. we have exploited the accessibility of the macrofilariae to examine quantitative and qualitative differences in both the macro- and microfilariae (mff) in relation to age in naturally infected cattle. autochthonous cattle at a site on the adamawa plateau, north cameroon, situated near a perennial simulium damnosum s.l. breeding site, were examined in three age group ... | 1992 | 1594291 |
| the development of onchocerca ochengi (nematoda: filariodea) to the infective stage in simulium damnosum s.l. with a note on the histochemical staining of the parasite. | onchocerca ochengi, an intradermal filarial parasite of cattle in africa, was shown to develop normally to the infective stage in a member of the simulium damnosum complex, almost certainly s. sanctipauli. the development of the parasite in the thoracic musculature and head of the fly was completed in 6 days at an ambient temperature of 25-30 degrees c. the larvae were very similar in rates of development, morphology and distribution to those of the human parasite o. volvulus in the same vector. ... | 1979 | 90413 |
| present progress towards the laboratory colonization of african simuliidae (diptera). | the laboratory colonization of african simuliids would facilitate critical work on many aspects of their biology and onchocerciasis vectors could be studied away from natural breeding-sites. in addition to a review of the literature of past achievements in this field, the authors' own studies are described: these centred on the simulium damnosum and s. neavei complexes because they include vectors of human onchocerciasis. other species studied included vectors of onchocerca gutturosa and avian h ... | 1975 | 1162730 |
| the differential dispersal of nulliparous and parous simulium damnosum. | dissections of simulium damnosum in the sudansavanna zone of cameroon indicated that nulliparous flies dispersed mainly inland away from their riverine breeding sites. parous flies also dispersed inland to the same distances as nulliparous flies, but mainly they stayed close to, or moved along, the banks of the breeding rivers. this tendency was most marked in the older parous flied. as a result of this differenital dispersal, the numbers of s. damnosum carrying infective larvae of onchocerca vo ... | 1975 | 1145728 |
| detection of the predators of simulium damnosum by the precipitin test. | saline cell free extracts of larvae of the simulium damnosum complex were used to immunize rabbits for the production of damnosum-antisera. injections into the lymph nodes produced a more specific antiserum than was obtained by intramuscular injection followed by absorption. this antiserum was used to identify by the precipitin test natural predators of s. damnosum collected from the bandama river in the ivory coast. various trichopteran larvae and odonatan nymphs and adults were found to be the ... | 1975 | 1124962 |
| studies on the attraction of simulium damnosum s.l. (diptera: simuliidae) to its hosts. i. the relative importance of sight, exhaled breath, and smell. | four traps used in capturing hunting female s. damnosum s.l. are discribed: the slat trap, the enclosure trap, the fan trap, and the sticky trap. in forest a man hidden inside a trap, but removing his exhaled breath through a long hose, attracted 4 times as many flies as did an unbaited trap. when the man exhaled normally into the trap the number of flies taken rose again by a further factor of 4. carbon dioxide gas, emitted from inside the trap attracted some two-thirds as many flies as a man e ... | 1976 | 1006802 |
| studies on the flight range and dispersal of simulium damnosum (diptera: simuliidae) in the rain-forest of cameroon. | five marking/recapture experiments were carried out on simulium damnosum in the rain-forest of the united republic of cameroon, in order to determine the regression in biting density at increasing distances from the marking point. flies were captured unfed, marked with fluorescent dust, and then released on the bank of a large river. recaptures were made over the six-seven days after marking, at seven stations situated from 200 m to 79 km along a large river, from the marking site. marked flies, ... | 1976 | 971003 |
| the intervals between the blood-meals of man-biting simulium damnosum (diptera: simuliidae). | six marking-recapture experiments were carried out with simulium damnosum in the cameroon republic, five in the rain-forest and one in the sudan-savanna zone. adult flies were marked by applying a small spot of oil paint to the mesonotum while they were engorging with blood on the legs of volunteers infected with onchocerca volvulus microfilariae. catches of wild flies were carried out for 12-13 days after the first day of marking, and all marked flies recaptured were examined. some of the flies ... | 1976 | 971002 |
| studies on the attraction of simulium damnosum s.l. (diptera: simuliidae) to its hosts. iii. experiments with animal-baited traps. | in the forest zone of the united republic of cameroon, a live chicken proved far more attractive to hunting s. damnosum s.l. than did a live sheep; but in the sudan-savanna zone, a sheep was more attractive than a chicken. it is suggested that the populations of flies in the two areas represented different species of the s. damnosum s.l. complex with different host-finding mechanisms, that in the forest (? s. squamosum) hunting mainly by smell, and that in the sudan savanna (? s. damnosum s.s.) ... | 1977 | 888186 |
| studies on the attraction of simulium damnosum s.l. (diptera: simuliidae) to its hosts. ii. the nature of substances on the human skin responsible for atrractant olfactory stimuli. | in the cameroon rain-forest, electric fan traps, baited with trousers which had been worn by men for several days, captured more females of s. damnosum s.l. than did traps baited with worn shirts of similar material. a number of human body fluids were used as bait, but only sweat appeared to contain the olfactory attractant(s). the fluid portion of filtered arm sweat attracted more flies than did the residue. the attractant substances from human skin would not dissolve directly in organic solven ... | 1977 | 871039 |
| [observations on the life cycle of o. ochengi in simulium damnosum s.l. in togo (author's transl)]. | in the focus of human onchocerciasis in togo (mono river), the authors collected 250 simulium damnosum s.l. engorged on a cow parasitized by o. dukei, o. ochengi, o. gutturosa and o. armillata. on 39 simulium damnosum dissected 24 h after the blood meal, 5 had ingested o. gutturosa, 1 o. armillata, 18 o. dukei and 6 o. ochengi; only for o. ochengi, the microfilariae have reached the hemocoel (3. s. damnosum on 6). from 48 h to 5 days, 6 on 132 s. damnosum contained developing larvae (2 simulium ... | 1978 | 754627 |
| the onchocerciasis focus at kinsuka/kinshasa (republic of zaire) in 1985. i. entomological aspect. | the entomological aspect of the onchocerciasis focus at kinsuka/kinshasa has not been studied since vector control was carried out in 1948. as in 1940, larvae of simulium damnosum s.l. are located in the arm of the zaire river flowing between mimosa island and the zairian bank. they are, however, scarce. cytotaxonomic studies showed that the s. squamosum group was the only member of the s. damnosum complex present in the region of kinshasa. physico-chemical analysis of the water at breeding site ... | 1990 | 2260901 |
| light trap studies on simulium damnosum s.l. in northern ghana. | the results of light trapping s. damnosum s.l. in northern ghana during both the wet and dry season are given. it is considered that some flight activity takes place throughtout the night at both seasons. flies in different physiological states behave differently and gravid females and newly emerged flies appear to be strongly phototactic. there is little evidence to suggest that light trapping is likely to be useful for the capture of blood engorged flies and for the routine monitoring of s. da ... | 1978 | 741509 |
| differential length of onchocerca volvulus infective larvae from the cameroon rain forest and savanna. | infective larvae from the savanna strain of onchocerca volvulus are significantly longer (662.6 +/- 66.8 microns; n = 99) than those from the forest strain (624.2 +/- 62.0 microns; n = 236). the length of the infective larvae is not influenced by the size, species or age post infectionem (pi) of the simulium damnosum s. l. vectors nor by their localization in the fly's head, thorax or abdomen, the worm load per fly or the thoracic volume per larva. however, the lengths of infective larvae within ... | 1990 | 2339243 |
| studies on the reinvasion of the onchocerciasis control programme in the volta river basin by simulium damnosum s.i. with emphasis on the south-western areas. | the aerial larvicidng operation of the onchocerciasis control programme of the world health organization which began in february 1975 resulted in a sharp reduction in simulium damnosum numbers. however, at the onset of the rainy season the fly population increased in certain areas. detailed surveys both on the ground and by helicopter did not reveal any significant failures of treatments that could account for the fly densities observed, and it was concluded that the flies must originate from so ... | 1979 | 575581 |
| the laboratory maintenance and rearing of simulium damnosum complex species as a research tool for the onchocerciasis control programme in the vola river basin. | the laboratory maintenance and rearing of stimulium damnosum complex species and the cytotaxonomic determination of reared larvae, has been useful to ocp in the following fields of investigation: 1. species identification of reinvading females. 2. distribution of biting populations of s. damnosum complex species. 3. identification of eggs and small larvae found within the ocp area. 4. host preferences of species within the complex. 5. vector potential of s. damnosum complex species for onchocerc ... | 1979 | 575451 |
| [circadian rhythm of metamorphosis and time of development of preimaginal instars of simulium damnosum s.i. (diptera, simuliidae) in the ivory coast]. | | 1979 | 232406 |
| [sampling methods for preimaginal populations of simulium damnosum theobald, 1903 (diptera, simuliidae) in west africa. ii. observations on choice of colours, evolution of the population and horizontal distribution by use of plastic strips (author's transl)]. | | 1977 | 203062 |
| [studies on the simulium damnosum complex in west africa - v. morphological identification of the females in ivory coast (author's transl)]. | the morphological identification of adult females of the simulium damnosum complex is essential for studies on the ecology and vector potential of the species concerned. detailed morphological studies of adult females obtained at breeding sites, where larvae had been identified cytotaxonomically, allowed the establishment of an identification key. this key, based on morphological characters of the antennae and maxillae, is dealing with the six species of the complex known to occur in the ivory c ... | 1977 | 196367 |
| a temporary focus of savanna species of the simulium damnosum complex in the forest zone of liberia. | savanna species of the simulium damnosum complex, the major vectors of the blinding savanna type of onchocerciasis, were considered to be rare in liberia, until the dry season of 1988. in 1988 they became a serious nuisance, biting people at the bong iron ore mine within the rain forest zone. s. damnosum s.str. and s. sirbanum were found breeding, in association with s. adersi a non man-biting savanna species, in a stream emerging from the mine's tailings pond. the local forest species were extr ... | 1991 | 1801141 |
| development of onchocerca volvulus microfilariae injected into simulium species from cameroon. | microfilariae (mff) of the savanna and forest strains of onchocerca volvulus (leuckart) were injected intrathoracically into adult females of simulium damnosum theobald sensu stricto, s.sirbanum vajime & dunbar, s.squamosum enderlein and s.mengense vajime & dunbar. nine days post infection (pi) 27-29% of the savanna mff and 31-38% of the forest strain had developed to third-stage larvae (l3), irrespective of the fly species, size or injection dose (5, 10 or 15 mff). savanna flies supported the d ... | 1991 | 1768922 |
| the development of onchocerca dukei and o. ochengi microfilariae to infective-stage larvae in simulium damnosum s.l. and in members of the s. medusaeforme group, following intra-thoracic injection. | neonate simulium females from an endemic area of human and bovine onchocerciasis in north-cameroon were injected in one set of experiments with microfilariae (mff) of onchocerca dukei and in another with mff of o. ochengi. onchocerca dukei was found to develop to infective third-stage larvae in simulium flies: 148 third-stage larvae (28.1% of injected mff) were recovered in s. hargreavesi, seven (10.4% of injected mff) in s. vorax, and 12 (1.3%) in s. damnosum s.l. onchocerca ochengi mff develop ... | 1991 | 1746982 |
| evaluation of larvicides for the control of simulium damnosum s.l. (diptera: simuliidae) in west africa. | the onchocerciasis control program of the world health organization is carrying out an extensive screening program in a search for new larvicides to be used for control of simulium damnosum s.l. emphasis has been given to finding a pyrethroid and a carbamate to supplement the organophosphates currently in use. these chemicals with differing modes of action, together with bacillus thuringiensis h-14, are being used in an attempt to cope with the development and spread of resistance to the organop ... | 1987 | 3504910 |
| temporary small-scale colonization of the beffa form of the simulium damnosum theobald complex (diptera: simuliidae) in africa. | two populations of the beffa form of simulium damnosum s.l. were colonized on a small scale for the first time in africa. the colonies survived for three and five generations, respectively. information gained led to improvements in adult handling techniques which proved adequate for colony maintenance despite the small numbers reared. nevertheless, large scale rearings are required to avoid inbreeding and to produce sufficient numbers for experimental purposes. | 1986 | 3507465 |
| [effect of a sublethal dose of an insect growth regulator on the physiology of onchocercosis vectors]. | in most of the large scale vector control programs, the larviciding operations are not fully successful, resulting in a surviving vector population due to the use of sublethal doses. this problem leads the authors to study the effect of such doses upon the future of the residual population in order to know if it represents an epidemiologically dangerous population. one insect growth regulator was selected to study this phenomenon using onchocerca volvulus as the parasite and simulium damnosum s. ... | 1992 | 1567265 |
| a new focus of onchoceriasis in the sudan. | a new focus of onchocerciasis is reported from upper atbara river area in the sudan. this river is a known seasonal breeding place of simulium damnosum. the area was sparsely populated in the past but now, following agricultural development, is inhibited mainly by immigrants from northern nigeria and chad. clinically the common features are skin changes of the legs, thighs buttocks, arms and trunk. other features are corneal opacities and small often deeply placed subcutaneous nodules. choroido- ... | 1975 | 1216316 |
| some observations on onchocerciasis including sowda in the yemen arab republic. | a pilot study on onchocerciasis and sowda was carried out in the south-western region of the yemen arab republic. of 61 persons examined in eight villages 35 (= 57%) were found positive for microfilariae by the skin-snip method, 13 had typical manifestations of sowda, 17 had other onchocercal-suggestive skin lesions and five had subcutaneous nodules. a single larva of simulium damnosum s.i. was collected in wadi barakani. numerous larvae and pupae of s. ruficorne and s. hargreavesi were taken in ... | 1979 | 442197 |
| onchocerciasis, malaria and trypanosomiasis in three resettlement schemes in western ethiopia. | epidemiological studies were carried out among 180 randomly chosen settler and 180 non-settler households in the three resettlement schemes of kishe, gera and didessa located in river valleys and highland areas of illubabor administrative region in western ethiopia. up to 49% of the indigenous populations (in kishe) and 0.9% of the settlers had onchocerciasis, with a mean density of 13.6 filariae per slide/skin snip for indigenous people and 9.4 for settlers. onchocerciasis prevalence rates were ... | 1991 | 1844511 |
| mermithid (nematoda: mermithidae) parasitism of simulium damnosum s.l. (diptera: simuliidae) in sierra leone and the need for vector control. | females of simulium damnosum theobald s.l. were systematically collected at four sites in the gorawa chiefdom of sierra leone, west africa, over a period of 15 mo from july 1986 to september 1987. the prevalence of mermithids infecting parous females varied from 0 to 7.9%, whereas the prevalence of mermithids in nulliparous females varied from 0 to 42.8%. the peak incidences of mermithid infection in nulliparous females occurred during the rainy season (15.2% in october 1986, 42.8% in august 198 ... | 1991 | 1875370 |
| hyperendemic onchocerciasis in the taraba river valley of gongola state (old adamawa province), nigeria. | a survey of the prevalence of onchocerciasis was carried out in the taraba river valley, nigeria where simulium damnosum s. l. is known to breed but about which no epidemiological data exists. skin biopsies taken from 2,876 persons in 14 communities were examined for the microfilariae of onchocerca volvulus. 100% infection rate was recorded in one of the communities, five other communities had prevalence rates between 81.0% and 94.7%. three communities had infection rates between 44.8% and 69.1% ... | 1991 | 1883152 |
| the transmission of onchocerciasis at a forest village in sierra leone. i. simulium damnosum s.l. biting densities and infection with onchocerca volvulus at five representative sites. | previous studies in the forest area of sierra leone have shown that transmission of onchocerca volvulus takes place many kilometers away from large breeding rivers and sometimes in open farmland. to determine where and when people in a forest village were most likely to be infected, catches of simulium damnosum s.l. were carried out every week for 12 months, at five sites in and near a village where onchocerciasis was mesoendemic. the number of flies caught per man a day at open farm sites was s ... | 1990 | 2076037 |
| the transmission of onchocerciasis at a forest village in sierra leone. ii. man-fly contact, human activity and exposure to transmission. | in the first of these papers we reported on the biting-densities of simulium damnosum s.l., vector of onchocerciasis, at sites in and near to a village in the forest area of sierra leone that was well separated from any large simulium breeding river. it was found that biting-densities and transmission levels were higher in open farmland than at riverside sites. in this paper we examine the relative time spent by the villagers at the same five sites in and near to the village of baoma lungibu, an ... | 1990 | 2076038 |
| 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 |
| [epidemiological status of onchocerciasis in the congo]. | analysis of 25 surveys carried out in the congo between 1978 and 1987 (covering nine of the ten administrative regions), during which 6,215 subjects were examined, showed that onchocerciasis is endemic in the southern part of the country. two main foci meeting at the southern exit of brazzaville (pool region) were identified. one focus in the djoué basin. the other is the zone along the congo river stretching from below brazzaville south west to the zaire border. two secondary foci were noted, o ... | 1990 | 2241306 |
| fecundities of different members of the simulium damnosum species complex in togo. | | 1986 | 3798548 |
| [study of the transmission of onchocerciasis in the surroundings of a refugee camp located in the savanna zone of cameroon]. | chadian refugees, most of whom are free from onchocerciasis, settled recently in a camp in a savanna area of the northern cameroon where the prevalence is about 80% and the blindness rate is 4% of the adult population. in view of the risks of onchocerciasis facing the immigrants, the authors carried out an entomological survey in this region aimed at determining the modes of transmission and assessing the possibilities for the control of this disease. after a three-month survey in the study area ... | 1990 | 2241307 |
| acid phosphatase activity in the larval stages of onchocerca volvulus developing in the vector simulium damnosum. | the staining patterns of acid phosphatase activity of the various larval stages of onchocerca volvulus from experimentally infected simulium damnosum s.l. have been described. the enzyme activity was localized in the anal vesicle/pore area of the first-stage larva, in the anal vesicle and intestine of the secong-stage larva and all over the body in the third-stage larva. early third-stage larvae could be differentiated from late third-stage infective larvae by the presence of pronounced enzyme a ... | 1978 | 726048 |
| maintenance of effective control of simulium damnosum in the face of insecticide resistance. | the control of onchocerciasis through reduction of its vector simulium damnosum depends on highly effective insecticide treatments directed against the larvae. as these treatments must be applied weekly over wide areas for many years, ideal conditions for the development of resistance have been created. resistance to organophosphate compounds has occurred. to maintain effective vector control, an intense operational research effort has been necessary. close and constant monitoring of susceptibil ... | 1990 | 2378230 |
| parasitologic survey of onchocerca volvulus infection in the nimiyama chiefdom, kono district, sierra leone. | infection due to onchocerca volvulus was investigated in the nimiyama chiefdom, kono district, sierra leone, where simulium damnosum s.l. is known to breed but no data on the prevalence and intensity of o. volvulus infection exists. of the 735 individuals sampled by the skin snip method in five villages, 471 (64%) were infected. the infection rate for males was significantly (p less than 0.05) higher than that of the females. two hundred and ninety-one (70.0%) of the 416 males skin snipped and 1 ... | 1989 | 2595798 |
| on the ecology and distribution of the species of the simulium damnosum complex in different bioclimatic zones of liberia and guinea. | a chromosomal identification of simulium damnosum material collected in liberia and guinea revealed five species of this complex. s. yahense vajime and dunbar: widely distributed in the rain forest zone (liberia, southern guinea) and in the fouta djallon mountains. breeding places typically in small watercourses, shaded streams and narrow rivers. s. sanctipauli vajime and dunbar: restricted to the rain forest zone. breeding confined to large rivers. s. soubrense vajime and dunbar: breeding estab ... | 1975 | 1189032 |
| mating, blood feeding, and oviposition of simulium damnosum theobald in the laboratory. | the development of suitable techniques for colonizing the vectors of human onchocerciasis in the laboratory would facilitate critical studies on many aspects of their biology. progress towards this end, however, has until now been prevented by the fact that no african simuliid had been induced to mate in captivity. the main vector of human onchocerciasis in africa is simulium damnosum, which exists in a number of different forms, some but not all of which bite man. during the present investigati ... | 1972 | 4540682 |
| morphometric differentiation of onchocerca volvulus and o. ochengi infective larvae. | by microinjection of cryopreserved microfilariae (mf) into nulliparous flies, a comparison of the lengths of the infective larvae (l3) of onchocerca volvulus and o. ochengi from the head of simulium damnosum s.l. (presumed s. sirbanum) has been made. the suitability of s. sirbanum as a host was similar for both onchocerca spp. the mean length +/- standard deviation of o. ochengi infective larvae measured in aqueous medium after storage of infected flies in liquid nitrogen was 762 +/- 63 microns ... | 1992 | 1566310 |
| cytological approaches to simuliid biosystematics in relation to the epidemiology and control of human onchocerciasis. | this paper presents an overview of advances in cytological research on the biosystematics of vector simuliid complexes in the areas of identification, age grading, and the evolution of resistance in relation to the epidemiology and control of human onchocerciasis. systematic theory is discussed and relevant examples are given to show its application in predicting and resolving current problems in species identification for new world and old world vector complexes. these complexes include simuliu ... | 1989 | 2680764 |
| studies on onchocerciasis in forest-savannah mosaic areas of nigeria. i. investigations in gbaragu, oji river. | reports on onchocerciasis in nigeria have been scanty, despite the size of the country and of the problem. a survey of the prevalence and transmission of the disease in the south-eastern communities of nigeria was commenced, with a year-long study of the vector and the clinical manifestations of the disease in a forest-savannah mosaic area on the oji river. microfilaraemia was found in 76% of the population, and nodules in 62%; there were no significant differences between male and female preval ... | 1991 | 1811439 |
| anthropophily, zoophily and roles in onchocerciasis transmission of the djodji form of simulium sanctipauli and s. squamosum in a forest zone of togo. | adult female simulium damnosum s.l. were caught at human and cattle bait at djodji in togo. two members of the simulium damnosum complex, the djodji form of s. sanctipauli (74.9% of the total catch) and s. squamosum (25.1%), were identified and both were mainly anthropophilic. although each species was also recorded feeding on cattle or turkey baits, most flies which were caught at animal baits did not take blood from them. flies caught unfed at the cattle bait tended to be larger and have highe ... | 1988 | 3175468 |
| epidemiological studies of onchocerciasis in savanna villages of sierra leone. | the overall prevalence of onchocerciasis was 78% and 73% in three villages of the woodland savanna of koinadugu and four villages of the savanna-forest mosaic of kambia respectively. the total number of persons examined was 611. in koinadugu the prevalence of microfilariae of onchocerca volvulus in skin snips from the iliac crest and canthus was 51.3% and 22.5% respectively while corresponding figures for kambia were 52.2% and 19.3%. the pattern of clinical manifestations were similar in both di ... | 1988 | 3194672 |
| [epidemiology of filariasis (onchocerciasis and bancroftosis) in the tala-mokolo region (mandara mountains of north cameroon)]. | the effect of the bancroftian filariasis on the health of the inhabitants are minimal in the study area, where the prevalence of the disease (nocturnal microfilaremia) is 0.4% only. but skin snips harboring onchocerca microfilariae are seen in 12.1% of the sample studied. onchocerciasis skin lesions, low visual acuity and blindness are often seen in the villages where the prevalence is high, among inhabitants more than 40 years of age. simulium damnosum is seldom seen in the area, except in the ... | 1986 | 3549025 |
| onchocerca-simulium complexes. v. the intake and subsequent fate of microfilariae of a guatemalan strain of onchocerca volvulus in forest and sudan-savanna forms of west african simulium damnosum. | | 1967 | 4966473 |
| artificial feeding of west african simulium damnosum theobald s.l. (diptera: simuliidae) on man, domestic mammals and birds. | a population of known species composition (mainly simulium damnosum s.s. with some s. sirbanum), was fed on chicken, guinea-fowl, rabbit, goat, sheep, and man, using simple techniques under similar conditions. significant differences in feeding rates were found between the different host species, on different parts of the body, at times also between different individuals of the same species, and between techniques employed. on less favoured hosts wild-caught flies usually gave better results tha ... | 1986 | 3563319 |
| onchocerciasis in sierra leone. i. studies on the prevalence and transmission at gbaiima village. | a longitudinal survey--parasitological, clinical, immunological and entomological--of onchocerciasis is being conducted in gbaiima village in sierra leone. the estimated annual transmission potential (atp) is 5863. more than 80% of the annual transmission occurs between october and december. four species of the simulium damnosum complex are known to breed in a nearby river. the relative role of these species as vectors has yet to be determined. the total population (598 persons) aged one year an ... | 1986 | 3603620 |
| studies on factors influencing the transmission of onchocerciasis. vii. a comparison of the onchocerca volvulus transmission potentials of simulium damnosum populations in four cameroon rain-forest villages and the pattern of onchocerciasis associated therewith. | | 1972 | 5038247 |
| observations on trichopteran predators of aquatic stages of simulium damnosum and other simulium species in ghana. | | 1972 | 5054491 |
| in vitro effects of ivermectin on onchocerca volvulus microfilariae assessed by observation and by inoculation into simulium damnosum sensu lato. | | 1990 | 2278078 |
| 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 |
| studies on the dynamics of transmission of onchocerciasis in a sudan-savanna area of north cameroon i. prevailing simulium vectors, their biting rates and age-composition at different distances from their breeding sites. | along the main water courses in the sparsely populated areas of the sous-préfecture of tcholliré, the vectors of onchocerciasis were mainly simulium damnosum s. str. and s. sirbanum, together with a small proportion of s. squamosum. over a period of one to three years, vector biting rates were measured at 23 fly-catching sites in the vicinities of nine villages with different endemicities of onchocerciasis. annual biting rates (abr) on man were estimated as 26,100-83,800 fly-bites per man per ye ... | 1987 | 3662664 |
| studies on the dynamics of transmission of onchocerciasis in a sudan-savanna area of north cameroon iii. infection rates of the simulium vectors and onchocerca volvulus transmission potentials. | populations of simulium damnosum s.str. and s. sirbanum were examined for infections with filarial parasites during three years in the areas of tcholliré and touboro, at sites at different distances from simulium breeding rivers, and in relation to villages with different endemicities of onchocerciasis. a total of 60,353 flies from 23 fly-catching sites were dissected. the overall infection rate was low, 11.8% of 35,357 parous flies dissected. 1681 flies (4.8% of the total parous) contained 3557 ... | 1987 | 3662666 |
| studies on the dynamics of transmission of onchocerciasis in a sudan-savanna area of north cameroon v. what is a tolerable level of annual transmission potential? | the prevalence and intensity of infection with onchocerca volvulus were assessed in population surveys in nine villages, situated at different distances from simulium damnosum s.l. breeding sites. the prevalence varied from 48 to 89%, the arithmetic mean densities of microfilariae per skin snip were between 16 and 109, and severe ocular lesions were found in from 1 to 22% of patients. annual transmission potentials (atp) were measured for up to three years in the near vicinity of nine villages a ... | 1987 | 3662668 |
| evidence of reduced susceptibility to ddt in controlling simulium damnosum (diptera: simuliidae) on the river niger. | | 1970 | 5312527 |
| [morphology of the larval stages of onchocerca volvulus in simulium damnosum and redescription of the microfilaria]. | | 1969 | 5392666 |
| occurrence of the savanna species of the simulium damnosum complex in liberia. | | 1987 | 3686648 |
| development of a method for the cytological identification of man-biting sibling species within the simulium damnosum complex. | a method is described for the preparation of adult malpighian tubule polytene chromosomes from members of the simulium damnosum complex. this method was used to show that the banding pattern is conserved between adult and larval tissues, and consequently it has been possible to demonstrate that within the s. sanctipauli subcomplex both s. soubrense 'b' and s. sanctipauli bite humans. the degree tubule development is correlated with the gonotrophic cycle and appears to be dependent on food source ... | 1986 | 3704475 |
| acquired resistance to onchocerca lienalis infections in simulium ornatum meigen and simulium lineatum meigen following passive transfer of haemolymph from previously infected simuliids (diptera, simuliidae). | this study describes experiments which demonstrate the presence of a parasite-induced or derived factor in the haemocoel of onchocerca lienalis-infected simuliids. haemolymph, when transferred from previously infected donor flies to previously untreated recipient flies, using fine glass needles, confers protection against a subsequent challenge to the recipients. in three trials using simulium ornatum sl. or s. lineatum, significant levels of protection in 'immunized' compared to 'challenge cont ... | 1986 | 3714299 |
| localized onchocerciasis vector control in the bahr el ghazal region of south-western sudan. i. precontrol. | over a two year period, onchocerciasis vector biting and transmission rates were recorded from 11 sites within a 40 km radius of wau, in the bahr el ghazal region of south-western sudan. these data provide the baseline on which the efficacy of localized vector control in the third year of the study, has been assessed (baker and abdelnur 1986). during 1018 collection days, 59,660 simulium damnosum s.l. vectors were attracted to man, 41,548 of which were dissected. 2.8% of the dissected flies were ... | 1986 | 3749738 |
| artificial feeding of west african simulium damnosum theobald s.l. (diptera: simuliidae) through membranes and their subsequent fecundity. | simulium damnosum s.l. females were offered blood through artificial membranes using a feeding apparatus in which the blood is kept warm and stirred. feeding rates and egg production were compared using a synthetic silicone or a latex membrane and ten different kinds of blood with and without added adenosine-tri-phosphate (atp). feeding rates were usually higher with silicone than with latex membranes. wild flies captured just before starting to feed on man, usually fed better than females that ... | 1986 | 3749739 |
| mermithid parasitism of simulium damnosum s.l. and the transmission of human onchocerciasis. | dissection data from a simulium damnosum s.l. population in northern ghana, heavily parasitized by the mermithid isomermis lairdi, are presented. a simple calculation gives reason to suppose that this parasitism may significantly reduce the transmission of onchocerciasis at certain seasons. | 1985 | 3832494 |
| quantitative studies on the transmission of onchocerca volvulus by simulium damnosum s.l. in the tukuyu valley, south west tanzania. | a survey of the simulium breeding and the transmission of onchocerca volvulus was carried out in and around the tukuyu valley, s.w. tanzania, s. damnosum s.l. was found breeding in the midstretches of the main rivers in the valley and their bigger tributaries, and also in the boundary river to malawi and the most northerly of the three rivers draining the livingstone mts. to lake nyasa (l. malawi). a total of 19,500 s. damnosum s.l. females was caught and 13,200 dissected. the annual biting rate ... | 1985 | 4089477 |
| the distribution of the simulium damnosum complex in sierra leone and its relation to onchocerciasis. | because of the paucity of literature concerning onchocerciasis and its vectors in sierra leone, new information of the geographical distribution of the simulium damnosum complex is presented in the context of a comprehensive review of what is known generally about s. damnosum s.l. in sierra leone, and how the data relate to the transmission of onchocerciasis. neither biting adults nor breeding sites have been found on the coastal plain and freetown peninsula, and these area seem to be free from ... | 1985 | 4096566 |
| microsporidan infection of simulium damnosum in west africa. | | 1974 | 4373561 |
| on the biology of simulium damnosum theoblad, 1903, the main vector of onchocerciasis in the mahenge mountains, ulanga, tanzania. | | 1969 | 4397649 |
| on the possibility of bovine onchocerca species infecting simulium damnosum s.l. in the forest zone of sierra leone. ii. biting densities and filarial infections in simulium spp. and culicoides spp. | previous studies of bovine onchocerca spp. in cattle in sierra leone indicated that only o. gutturosa was transmitted in the forest zone at high intensity. to determine its vector(s) and the extent to which onchocerca-like infections in simulium damnosum were likely to be of bovine origin, three lines of investigation were pursued. firstly, a study was made of the biting flies attacking an ox bait animal over a 14-month period at njala university campus, near bo. secondly, attempts were made to ... | 1989 | 2619375 |
| identification of larval and adult simulium yahense and simulium sanctipauli based on species-specific enzyme markers and their distribution at different breeding habitats in central liberia. | human-biting adults and late instar larvae of the simulium damnosum complex from four ecologically different simuliid breeding habitats in the firestone rubber plantation at harbel, liberia, were identified morphologically and the monthly species composition of each site was recorded. samples of the predominant species found at each site were assayed electrophoretically for species-specific variants of phosphoglucomutase (pgm) and trehalase (tre). enzyme identifications of flies and larvae were ... | 1986 | 2947482 |
| management of insecticide resistance in control of the simulium damnosum complex by the onchocerciasis control programme, west africa: potential use of negative correlation between organophosphate resistance and pyrethroid susceptibility. | 1. resistance of some populations of the simulium damnosum complex to temephos (100-fold at the lc50 level), with degrees of cross-resistance to chlorphoxim (14-fold) and other organophosphate insecticides, follows intensive larvicidal control of s. damnosum s.l. in west african river systems since 1975 by the who onchocerciasis control programme. 2. larvae of at least three sibling species of the s. damnosum complex have become organophosphate-resistant: these are the forest species s. sanctipa ... | 1987 | 2979527 |
| onchocerciasis transmission levels and simulium damnosum complex biting activity at riverside and rice field sites in sierra leone. | biting densities of the simulium damnosum theobald complex of blackflies and their levels of parasitism by onchocerca volvulus (leuckart) were compared at two ecologically contrasted sites in the southern province of sierre leone, west africa: by the tabe riverside close to gbaiima village where onchocerciasis is hyperendemic (63.1% positive skin-snips) and in open rice fields 2 km from the mesoendemic (54.9%) village of senehun. using a combination of morphometric and enzyme electrophoresis tec ... | 1988 | 2980195 |
| electrophoretic patterns in anopheles gambiae and simulium damnosum. | | 1973 | 4799124 |
| the intake and transmissibility of onchocerca volvulus microfilariae by simulium damnosum fed on patients treated with diethylcarbamazine, suramin or mel w. | the best hope for the control of transmission of onchocerca volvulus over much of africa lies in combining larvicidal measures directed against the simulium vectors with chemotherapeutic measures designed to reduce the reservoir of transmissible microfilariae in man.there are few drugs effective against o. volvulus. diethylcarbamazine kills the microfilariae but has virtually no effect on the adult worms. suramin kills adult worms and many, but not all, of the microfilariae. mel w kills adult wo ... | 1968 | 4881069 |
| the simulium control scheme at abuja, northern nigeria, and its effect on the prevalence of onchocerciasis in the area. | this account of the conduct of the similium control scheme at abuja, northern nigeria, over the period 1956-66 shows that, by larvicide treatment of some 160 km of rivers with ddt in the early wet season, the simulium damnosum density has been reduced by about 90% of its precontrol level each year over an area of more than 3000 km(2).a skin-snip survey, in which 6748 persons were examined (of whom 5700 lived within the controlled area and 1048 in a comparison area) during 1966, indicates that th ... | 1968 | 4972620 |
| observations on chicken-biting blackflies in cameroon with a discussion of parous rates of simulium damnosum. | | 1972 | 5021565 |
| [study on the type of spillway of a dam unfavorable to the taking root of simulium damnosum (diptera, simuliidae)]. | | 1968 | 5303667 |
| prospects for the control of onchocerciasis in africa with special reference to the volta river basin. | onchocerciasis is found in association with all the main river systems of northern tropical africa, and there are endemic foci south of the equator. heavy and prolonged infection may cause blindness and intense pruritus. the vectors, simulium damnosum and s. neavei, are also intolerable pests when they swarm. the disease and its vector together cause serious economic loss and are a main cause of the depopulation of river valleys in the savanna lands.the basin of the river volta, in which the wor ... | 1969 | 5307598 |
| aerial application of larvicides for control of simulium damnosum in ghana: a preliminary trial. | | 1970 | 5311068 |
| [researches on larvae of ascaridida nematodes found in simulium damnosum]. | | 1969 | 5392755 |
| dry season survival of simulium damnosum theobald 1903 (diptera: simuliidae) in northern ghana, west africa. | | 1971 | 5145117 |
| on the possibility of bovine onchocerca species infecting simulium damnosum s.l. in the forest zone of sierra leone. i. parasitological aspects. | as part of a study to assess to what extent onchocerca-like infections in s. damnosum s.l. in the forest zone of sierra leone were likely to be of bovine origin, onchocerca infections were studied by post mortem examination of cattle killed at bo abattoir and by examination of skin biopsies from cattle born and reared at njala, in the forest zone, and musaia, in the savanna zone. post mortem studies of 45 cattle which had originated from northern sierra leone and guinea revealed a prevalence of ... | 1989 | 2619374 |
| [morphological studies of unknown filarial larvae from simulium damnosum, the vector of onchocerciasis, and from s. kenyae in liberia with reference to their possible final hosts]. | | 1972 | 4634262 |
| a mosquito-virulent bacillus sphaericus in adult simulium damnosum from northern nigeria. | from newly emerged adult simulium damnosum from kaduna river, northern nigeria, a mosquito-virulent strain of bacillus sphaericus was isolated. in another four cases non-virulent b. sphaericus were present. the isolate exerted a lc50 of 50 spores/ml for culex pipiens l4-larvae and was less virulent for anopheles stephensi (400 sp/ml) and aedes aegypti (800 sp/ml). | 1984 | 6720123 |
| the timing of the first blood meal in simulium damnosum theobald. | | 1970 | 5485704 |
| a note on variation within simulium damnosum in the forest zone of west cameroon. | | 1970 | 5485705 |
| [control of simulium damnosum (diptera, simuliidae) in portuguese guinea]. | | 1967 | 5583409 |
| the control of simulium damnosum theobald (diptera, simuliidae) in the region of the volta dam. | | 1967 | 5625703 |
| [natural infection of simulium damnosum with onchocerca volvulus in the savannahs of guinea]. | | 1968 | 5720330 |
| [study of populations of simulium damnosum theobald, 1903 (diptera: simuliidae) in zones of temporary deposits. 3. possible correlation between certain meterologic phenomena and the reappearance of the females at the beginning of the rainy season]. | | 1967 | 5631027 |
| studies on factors influencing the transmission of onchocerciasis. vi. the infective biting potential of simulium damnosum in different bioclimatic zones and its influence on the transmission potential. | | 1968 | 5703697 |
| dam-spillway breeding of simulium damnosum theobald in northern ghana. | | 1965 | 5862608 |
| studies on factors influencing the transmission of onchocerciasis. 8. the escape of infective onchocerca volvulus larvae from feeding 'forest' simulium damnosum. | | 1973 | 4723217 |
| [on the distribution of simulium damnosum in liberia (author's transl)]. | | 1973 | 4743773 |
| quantitative studies on the transmission of onchocerca volvulus by simulium damnosum in the bong range, liberia. | | 1973 | 4744222 |
| unknown filarial larvae and zoophily in simulium damnosum in liberia. | | 1969 | 5824289 |
| infective filaria larvae, other than onchocerca volvulus, in simulium damnosum. | | 1967 | 6063495 |
| identification of two west african black flies (diptera: simuliidae) of the simulium damnosum species complex by analysis of cuticular paraffins. | simulium damnosum is known to be a sibling species complex with at least 24 cytotaxonomically distinct forms in africa. of these, six occur in the area of west africa covered by the world health organization onchocerciasis control programme. they are all vectors of onchocerca volvulus, and several are capable of migrating great distances. we report here a comparatively simple chemical method of species identification using individual adult females of pooled samples that have been collected and s ... | 1981 | 6118031 |