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parasites of domestic and wild animals in south africa. xxxi. adult ixodid ticks on sheep in the cape province and in the orange free state.four to 10 dorper sheep on each of 12 farms in the cape province and 3 farms in the orange free state were examined for adult ixodid ticks at approximately 2- to 4-weekly intervals over periods varying from 4 to 18 months, commencing during january, february or april 1989. the farms in the cape province were located in the north-west, south-west and south of the province. those in the orange free state were situated in the north-east and in the south. the sheep in the cape province harboured 10 ...19921297957
parasites of domestic and wild animals in south africa. xxv. ixodid ticks on sheep in the north-eastern orange free state and in the eastern cape province.the tick burdens of 115 merino sheep, slaughtered over a period of 15 consecutive months on a farm in the north-eastern orange free state, were determined. a total of 7 ixodid and 1 argasid tick species were recovered and the seasonal abundances of boophilus decoloratus, hyalomma marginatum rufipes, margaropus winthemi and rhipicephalus evertsi evertsi were determined. one hundred and forty-nine merino sheep were slaughtered over periods varying from 10 to 25 months on 3 farms in eastern provinc ...19911923373
the virtual absence of culicoides imicola (diptera: ceratopogonidae) in a light-trap survey of the colder, high-lying area of the eastern orange free state, south africa, and implications for the transmission of arboviruses.altogether 52 078 culicoides biting midges of 35 species were collected during february 1990 and 1993 in 40 light-trap collections made on 17 cattle and/or sheep farms in the bethlehem and fouriesburg districts of the colder, high-lying eastern orange free state. culicoides (avaritia) bolitinos was by far the most abundant species, representing 50.9% of all specimens collected. culicoides (a.) imicola, considered to be the most common stock-associated species in the summer rainfall areas of sout ...19947501364
the role of hyalomma ticks in foot infestations and temporary lameness of sheep in a semi-arid region of south africa.an outbreak of lameness amongst merino lambs, associated with the presence of hyalomma ticks, was investigated on a farm in the south-western free state, south africa. the purpose was to follow the progress of the condition and to determine the extent of involvement of the two hyalomma species which occur in the region. the flock of experimental sheep (n = 460) ranged free in natural veld under extensive farming conditions. during september and october 1993, adult ewes and lambs in this flock we ...19958628574
the distribution of pasteurella haemolytica serotypes among cattle, sheep, and goats in south africa and their association with diseases.over an 8-year period (september 1986 to march 1994), a total of 497 organ specimens from sheep and goats and 96 from cattle, were received for their isolation of pasteurella haemolytica. they were collected in seven geographical areas in south africa (as it existed before the april 1994 elections). these areas include the eastern cape, transvaal (new name: gauteng), nambia, orange free state (new name: free state), natal (new name: kwazulu-natal), western cape and the northern cape. this invest ...19958668319
ticks and tick-borne diseases of livestock belonging to resource-poor farmers in the eastern free state of south africa.the paper provides a summary of three studies conducted in the eastern free state of south africa between 1998 and 2000. in a questionnaire-based study approximately 21% of interviewed resource-poor farmers (n = 150) indicated that they experienced problems with ticks and tick-borne diseases. about 56% of farmers indicated that tick-related problems were most severe in summer, while 32% indicated that the most problems were encountered in winter. about 12% indicated that the tick problems were e ...200214570134
a survey of tick control methods used by resource-poor farmers in the qwa-qwa area of the eastern free state province, south africa.a survey conducted in five villages in a resource-poor farming community in qwa-qwa, using the rapid rural appraisal technique and a questionnaire survey, showed that a significant proportion of the farmers (84%) use traditional or alternative methods to control ectoparasites, while 16% use commercial acaricides (chi2 = 7.1; p < or = 0.05). alternative control methods included the use of used engine oil, household disinfectant and paraffin. killing of ticks was the main reason for control (40%), ...200516300193
parasitic helminths of veterinary importance in cattle, sheep and goats on communal farms in the northeastern free state, south africa.the purpose of the study was to record and determine intensities, seasonal incidence and distribution of helminth parasites of veterinary importance that occur in cattle, sheep and goats in the northeastern free state. the study was conducted at harrismith and kestell and in qwa-qwa from march 2000 to may 2001. cattle of various breeds (including bonsmara, simmentaler and friesian), merino sheep and angora goats were sampled. faecal samples were analysed using the mcmaster and visser sieve techn ...200312967050
neurotoxicity in calves induced by the plant, nierembergia hippomanica miers var. violacea millán in south africa.the plant nierembergia hippomanica var. violacea has been incriminated in field outbreaks of neurotoxicity in calves in the free state province. hepatotoxicity and electrocardiogram (ecg) deviations were induced in a sheep dosed with 5 g/kg dried plant material on four consecutive days. a calf dosed with 2.5 g/kg dried plant material, on two consecutive days, did not show overt clinical changes. voluntary ingestion of approximately 30 g/kg fresh flowering plants by a second calf resulted in nerv ...199910631710
a survey of the mosquito and culicoides faunas at two localities in the karoo region of south africa with some observations of bionomics.the mosquito and culicoides faunas were surveyed at bethulie and luckhoff in the arid karoo region, south orange free state, to determine which species occurred, their relative prevalence and the effects of rainfall. the feeding preferences of these insects were also investigated by means of baited catches. twenty-three mosquito species and 16 culicoides species were collected. the commonest mosquito species, with their feeding preferences, if known, were as follows: culex (culex) univittatus th ...19807454229
blood selenium levels of sheep in some districts of the northern orange free state: the bultfontein area.blood selenium levels of apparantly healthy, adult sheep from the bultfontein area, as determined by neutron activation, varied between 0,165 and 0,500 micrograms/ml. due to the absence of anaemia, a symptom which could be taken as one of the earliest signs of chronic selenosis, these values suggest the intake of high but non-toxic amounts of selenium.19846492062
worm control under flock conditions in the grassveld areas of the eastern cape and eastern organge free state. 19724680375
the seasonal abundance of adult ixodid ticks on merino sheep in the south-western orange free state.with the exception of october, when no collections were made, adult ticks were collected at weekly intervals from february 1986 to january 1987 from 20 randomly selected sheep out of a flock of 60. ixodes rubicundus was the most abundant tick and was present from april to september with a peak during may. hyalomma marginatum rufipes was the next most numerous tick. it was recovered throughout the year with peak burdens being recorded from november to april. small numbers of a rhipicephalus sp. ( ...19883210216
seasonal incidence of karoo paralysis in relation to the infestation density of female ixodes rubicundus.the epidemiology of karoo paralysis, induced by the tick ixodes rubicundus, was investigated in a paralysis-enzootic area of the southwestern orange free state, republic of south africa. sheep became paralysed during the last week of april and the first week of may during the 1985 and 1986 seasons, respectively. paralysis cases were recorded up until july, but most paralysis cases occurred during the first week of may with a second but smaller peak occurring during june. tick numbers on paralyse ...19892815541
studies on an outbreak of wesselsbron virus in the free state province, south africa.in early march 1996, wesselsbron (wsl) virus caused mortality among lambs on a farm near bultfontein in the northern free state province, south africa. mosquito collections were therefore undertaken from 27 march to 1 april to collect floodwater aedes mosquitoes for attempts at virus isolation. in all, 4,732 floodwater aedes were tested; 5 wsl, 1 middelburg (mid), and 5 unidentified viruses were isolated from 3,052 aedes (neomelaniconion) mcintoshi/luridus (minimum infection rate [mir] for wsl = ...19989599322
spatial and temporal variations in the commencement of seasonal activity in the karoo paralysis tick, ixodes rubicundis.successful prophylaxis of paralysis, induced in small stock by feeding female ixodes rubicundus, is dependent on the accurate determination of the commencement of seasonal activity by the tick. the commencement of this activity was recorded for 11 consecutive years on a farm in the south-western free state, south africa, and for shorter periods on other farms, some of these in regions with markedly colder climates. the colder the mean minimum atmospheric temperatures during the 2 months precedin ...19969173361
seasonal dynamics of the karoo paralysis tick (ixodes rubicundus): a comparative study on merino and dorper sheep.karoo paralysis in south africa is induced in livestock by feeding female ixodes rubicundus ticks when infestation densities on hosts exceed certain critical levels. it has been shown previously that angora goats are at a higher risk of being paralysed than merino sheep, and such differences have been related to differences in feeding behaviour and spatial distribution of the two small-stock breeds. we hypothesized that differences in infestation densities with karoo paralysis ticks would also o ...19969173358
the diagnosis of wesselsbron disease in a new-born lamb by immunohistochemical staining of viral antigen.wesselsbron disease (wsl) was diagnosed in a 2-d-old lamb on a farm in the north-eastern free state province where a few abortions and neonatal deaths occurred in sheep in april 1994. the liver of the lamb was slightly swollen and orange-brown and, microscopically, it revealed single or small groups of necrotic hepatocytes that were randomly scattered throughout the lobules. other histopathologic hepatic lesions included the presence of acidophilic bodies, intranuclear inclusion bodies in a few ...19958600439
suspected facial eczema in sheep in the central orange free state.facial eczema is known to occur in the humansdorp district of the cape province. during june 1982-january 1984, 5 outbreaks of hepatogenous photosensitivity occurred in sheep in central districts of the orange free state. in one of these outbreaks a diagnosis of suspected facial eczema was made histologically.19846543453
epididymitis of rams in the central and southern districts of the orange free state.scrotal palpation, microscopical examination of semen smears and the application of bacteriological techniques, revealed the incidence of actinobacillus seminis and brucella ovis infection of rams in the central and southern districts of the orange free state to be 2,9% and 4,3%, respectively. more dorper than merino rams were affected. although clinically detectable epididymitis was found in 5,9% of rams examined, infection with a. seminis and b. ovis, as measured by the presence of neutrophils ...19846533305
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