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Parasites of South African wildlife. XIX. The prevalence of helminths in some common antelopes, warthogs and a bushpig in the Limpopo province, South Africa
2011
Ilana C. van Wyk | Joop Boomker
Little work has been conducted on the helminth parasites of artiodactylids in the northern and western parts of the Limpopo province, which is considerably drier than the rest of the province. The aim of this study was to determine the kinds and numbers of helminth that occur in different wildlife hosts in the area as well as whether any zoonotic helminths were present. Ten impalas (Aepyceros melampus), eight kudus (Tragelaphus strepsiceros), four blue wildebeest (Connochaetes taurinus), two black wildebeest (Connochaetes gnou), three gemsbok (Oryx gazella), one nyala (Tragelaphus angasii), one bushbuck (Tragelaphus scriptus), one waterbuck (Kobus ellipsiprymnus), six warthogs (Phacochoerus aethiopicus) and a single bushpig (Potamochoerus porcus) were sampled from various localities in the semi-arid northern and western areas of the Limpopo province. New host–parasite associations included Trichostrongylus deflexus from blue wildebeest, Agriostomum gorgonis from black wildebeest, Stilesia globipunctata from the waterbuck and Fasciola hepatica in a kudu. The mean helminth burden, including extra-gastrointestinal helminths, was 592 in impalas, 407 in kudus and blue wildebeest, 588 in black wildebeest, 184 in gemsbok, and 2150 in the waterbuck. Excluding Probstmayria vivipara, the mean helminth burden in warthogs was 2228 and the total nematode burden in the bushpig was 80. The total burdens and species richness of the helminths in this study were consistently low when compared with similar studies on the same species in areas with higher rainfall. This has practical implications when animals are translocated to areas with higher rainfall and higher prevalence of helminths.
Показать больше [+] Меньше [-]The dynamics of questing ticks collected for 164 consecutive months off the vegetation of two landscape zones in the Kruger National Park (1988–2002). Part II. <i>Rhipicephalus appendiculatus</i> and <i>Rhipicephalus zambeziensis</i>
2011
Arthur M. Spickett | Gordon J. Gallivan | Ivan G. Horak
The study aimed to assess the long-term population dynamics of questing Rhipicephalus appendiculatus and Rhipicephalus zambeziensis in two landscape zones of the Kruger National Park (KNP). Ticks were collected by dragging the vegetation monthly in three habitats (grassland, woodland and gully) at two sites in the KNP (Nhlowa Road and Skukuza) from August 1988 to March 2002. Larvae were the most commonly collected stage of both species. More R. appendiculatus were collected at Nhlowa Road than at Skukuza, with larvae being most abundant from May to August, while nymphs were most abundant from August to December. Larvae were most commonly collected in the gullies from 1991 to 1994, but in the grassland and woodland habitats from 1998 onwards. Nymphs were most commonly collected in the grassland and woodland. More R. zambeziensis were collected at Skukuza than at Nhlowa Road, with larvae being most abundant from May to September, while nymphs were most abundant from August to November. Larvae and nymphs were most commonly collected in the woodland and gullies and least commonly in the grassland (p < 0.01). The lowest numbers of R. appendiculatus were collected in the mid-1990s after the 1991/1992 drought. Rhipicephalus zambeziensis numbers declined after 1991 and even further after 1998, dropping to their lowest levels during 2002. The changes in numbers of these two species reflected changes in rainfall and the populations of several of their large herbivore hosts, as well as differences in the relative humidity between the two sites over time.
Показать больше [+] Меньше [-]Efficacy of fosfomycin in controlling streptococcosis in Nile tilapia (Oreochromis niloticus)
2011
M.M.A. Hussein | W. H. Hassan
A study was conducted to investigate the efficacy of fosfomycin in controlling streptococcosis in Nile tilapia (Oreochromis niloticus). The minimum inhibitory concentrations (MICs) of fosfomycin against multiple S. iniae isolates showed a sensitivity range of 12.5- 25 'g/mL. The fosfomycin dose levels tested were 40, 60, and 80 mg of active ingredient per kilogram fish per day. Administration of medicated feed started one day after infection by immersion exposure to S. iniae and continued for eight days. Survival rates of fosfomycin treated groups were 90, 100 and 96.6% with an average survival of 95. 53 %. On contrary, survival rates of infected non treated groups were 3.3%. All survivors and negative control groups showed no clinical signs, no gross pathology together with negative S. iniae re-isolation.
Показать больше [+] Меньше [-]Ixodid ticks, fleas and lice infesting dogs and cats in Hawassa, southern Ethiopia
2011
Bersissa E. Kumsa | Shewit Mekonnen
This study investigated the prevalence, risk factors and species composition of ticks, fleas and lice infesting dogs and cats in and around Hawassa in southern Ethiopia. In total, 200 dogs and 100 cats were examined from November 2008 to April 2009. Of the dogs and cats examined, 99.5% and 91.5%, respectively, were infested with one or more species of ticks, fleas or lice. The overall prevalence was higher in dogs than in cats. A total of six different species of ectoparasites were collected and identified from dogs, but only three species from cats. Ctenocephalides felis was the predominant species amongst the animals, with a prevalence of 82.9% on dogs and 67% on cats. Other prevalent species on dogs included Ctenocephalides canis (73.8%), Heterodoxus spiniger (4%), nymphs of Amblyomma spp. (3.5%), Pulex irritans (2.5%) and Haemaphysalis leachi (0.5%). C. canis (18%) and P. irritans (6%) were also found on cats. More female than male fleas and lice were observed. The study revealed that the prevalence of fleas, ticks and lice on dogs was not significantly different between male and female animals or between young and adult dogs. However, the prevalence of these ectoparasites was significantly higher in female than in male and in adult than in young cats. The study showed that the prevalence of ectoparasites on both dogs and cats was significantly higher on animals with flea allergy dermatitis (FAD) than those without FAD, and on animals with lesions on their skin compared with those without lesions.
Показать больше [+] Меньше [-]Studies on pathogenicity of Aeromonas species to native breed (Fayoumi) chickens
2011
Zeinab M. S. Amin Girh | K. M. El-Bayoumi | Eman. R. Hassan | K. M. Mahgoob
The pathogenic effect of representative local isolates of Aeromonas organisms was studied on 1٠0 native breed chickens. At 2 weeks of age, one hundred chicks were grouped into four equal groups (1-4); 25 birds each; after collection of fecal from all groups, examined and proved to be free from Aeromonas species. All groups were subcutaneously (s.c) inoculated with 0.5 ml containing 9×105 cfu /bird. Group 1 of chickens was infected by A. hydrophila; while group 2 was infected with A. caviae. The third group was infected with A. sobria; while, chicks of Group 4 were kept as non infected control. Results were showed mild clinical signs in some birds in the form of alternative diarrhea. Post mortem lesions showed general congestion of all carcasses. In severely emaciated cases the lesions were confined to the intestine, which filled with watery fluid and distended with gas. Results of Aeromonas reisolation revealed that all collected weekly fecal swabs were positive. While, percentage of A. hydrophila and A. caviae was 100% out of all tested organs, while isolation of A. sobria was 100%, 100% and 80% from liver, intestine and heart; respectively. Histopathological examination of infected chicken organs showing focal coaggulative necrosis in liver with mononuclear cells infiltration that varied in severity between groups as less severe in A. hydrophila (Gr.1) than A. caviae (Gr. 2), while A. sobria (Gr. 3) was markedly affected showing severe degenerated and dissociated hepatocytes. Intestinal changes were severe in group 3 than 2 while group 1 showing the mildest comparatively the changes was consist of necrosed mucosa, gland with leucocytic infiltration in lamina propria. Under the condition of our study we can conclude that the used Aeromonas isolates from field diseased chickens were of mild pathogenicity to s.c. inoculated 12 days old Fayoumi chicks with long course affection.
Показать больше [+] Меньше [-]The dynamics of questing ticks collected for 164 consecutive months off the vegetation of two landscape zones in the Kruger National Park (1988–2002). Part III. The less commonly collected species
2011
Gordon J. Gallivan | Andrea Spickett | Heloise Heyne | Arthur M. Spickett | Ivan G. Horak
Despite many studies regarding tick ecology, limited information on long-term changes in tick populations exist. This study assessed the long-term population dynamics of the less frequently collected questing ixodid ticks in the Kruger National Park (KNP). From 1988 to 2002, monthly dragging of the vegetation was performed in three habitats (grassland, woodland and gully) at two sites in the KNP (Nhlowa Road, Landscape Zone 17, and Skukuza, Landscape Zone 4). Amblyomma marmoreum and Rhipicephalus evertsi evertsi were collected as larvae most commonly. Most A. marmoreum larvae were collected at Skukuza and numbers peaked from March to July. More R. evertsi evertsi larvae were collected at Nhlowa Road and numbers peaked in summer and in winter, while at Skukuza there was a single peak in spring. Haemaphysalis elliptica, Rhipicephalus simus and Rhipicephalus turanicus were collected as adults most commonly. More Ha. elliptica and R. turanicus were collected at Nhlowa Road than at Skukuza, while R. simus numbers from the two sites were approximately equal. Ha. elliptica were collected most often between February and June, and R. simus and R. turanicus during February and March. All three species were collected more frequently in gullies than in grassland or woodland. Their numbers increased in 1994/1995 following an eruption of rodents, the preferred hosts of the immature stages. The different host-seeking strategies of ticks largely determine the development stage at which they are likely to be collected during vegetation dragging and reflect a complex interaction between ticks, their hosts and the environment.
Показать больше [+] Меньше [-]An investigation into the possibility of bluetongue virus transmission by transfer of infected ovine embryos
2011
Venter, Estelle H(University of Pretoria Department of Veterinary Tropical Diseases) | Gerdes, Truuske(University of Pretoria Department of Theriogenology) | Wright, Isabel(University of Pretoria Virology Section) | Terblanche, Johan(University of Pretoria Department of Theriogenology)
Bluetongue (BT), a disease that affects mainly sheep, causes economic losses owing to not only its deleterious effects on animals but also its associated impact on the restriction of movement of livestock and livestock germplasm. The causative agent, bluetongue virus (BTV), can occur in the semen of rams and bulls at the time of peak viraemia and be transferred to a developing foetus. The risk of the transmission of BTV by bovine embryos is negligible if the embryos are washed according to the International Embryo Transfer Society (IETS) protocol. Two experiments were undertaken to determine whether this holds for ovine embryos that had been exposed to BTV. Firstly, the oestrus cycles of 12 ewes were synchronised and the 59 embryos that were obtained were exposed invitro to BTV-2 and BTV-4 at a dilution of 1 x 10(2.88) and 1 x 10(3.5) respectively. In the second experiment, embryos were recovered from sheep at the peak of viraemia. A total of 96 embryos were collected from BTV-infected sheep 21 days after infection. In both experiments half the embryos were washed and treated with trypsin according to the IETS protocol while the remaining embryos were neither washed nor treated. All were tested for the presence of BTV using cell culture techniques. The virus was detected after three passages in BHK-21 cells only in one wash bath in the first experiment and two unwashed embryos exposed to BTV-4 at a titre of 1 x 10(3.5). No embryos or uterine flush fluids obtained from viraemic donors used in the second experiment were positive for BTV after the standard washing procedure had been followed. The washing procedure of the IETS protocol can thus clear sheep embryos infected with BTV either in vitro or in vivo
Показать больше [+] Меньше [-]The dynamics of questing ticks collected for 164 consecutive months off the vegetation of two landscape zones in the Kruger National Park (1988-2002). Part II. Rhipicephalus appendiculatus and Rhipicephalus zambeziensis
2011
Spickett, Arthur M(Onderstepoort Veterinary Institute Parasites, Vectors & Vector-borne Diseases Programme) | Gallivan, Gordon J(Ottawa Parasites, Vectors & Vector-borne Diseases Programme) | Horak, Ivan G(Ottawa University of Pretoria Department of Veterinary Tropical Diseases)
The study aimed to assess the long-term population dynamics of questing Rhipicephalus appendiculatus and Rhipicephalus zambeziensis in two landscape zones of the Kruger National Park (KNP). Ticks were collected by dragging the vegetation monthly in three habitats (grassland, woodland and gully) at two sites in the KNP (Nhlowa Road and Skukuza) from August 1988 to March 2002. Larvae were the most commonly collected stage of both species. More R. appendiculatus were collected at Nhlowa Road than at Skukuza, with larvae being most abundant from May to August, while nymphs were most abundant from August to December. Larvae were most commonly collected in the gullies from 1991 to 1994, but in the grassland and woodland habitats from 1998 onwards. Nymphs were most commonly collected in the grassland and woodland. More R. zambeziensis were collected at Skukuza than at Nhlowa Road, with larvae being most abundant from May to September, while nymphs were most abundant from August to November. Larvae and nymphs were most commonly collected in the woodland and gullies and least commonly in the grassland (p < 0.01). The lowest numbers of R. appendiculatus were collected in the mid-1990s after the 1991/1992 drought. Rhipicephalus zambeziensis numbers declined after 1991 and even further after 1998, dropping to their lowest levels during 2002. The changes in numbers of these two species reflected changes in rainfall and the populations of several of their large herbivore hosts, as well as differences in the relative humidity between the two sites over time
Показать больше [+] Меньше [-]Ticks of four-toed elephant shrews and Southern African hedgehogs
2011
Horak, Ivan G(University of Pretoria Department of Veterinary Tropical Diseases) | Welman, Shaun(Nelson Mandela Metropolitan University Nelson Mandela Metropolitan University) | Hallam, Stacey L(Nelson Mandela Metropolitan University Nelson Mandela Metropolitan University) | Lutermann, Heike(University of Pretoria Department of Zoology and Entomology) | Mzilikazi, Nomakwezi(Nelson Mandela Metropolitan University Nelson Mandela Metropolitan University)
Several studies on ticks infesting small mammals, including elephant shrews, have been conducted in South Africa; however, these studies have included only a single four-toed elephant shrew and no hedgehogs. This study thus aimed to identify and quantify the ixodid ticks infesting four-toed elephant shrews and Southern African hedgehogs. Four-toed elephant shrews (Petrodromus tetradactylus) were trapped in dense shrub undergrowth in a nature reserve in north-eastern KwaZulu-Natal. They were separately housed, first in cages and later in glass terraria fitted with wire-mesh bases to allow detached ticks to fall through for collection. Southern African hedgehogs (Atelerix frontalis) were hand caught on a farm in the eastern region of the Northern Cape Province and all visible ticks were collected by means of tweezers while the animals were anaesthetised. The ticks from each animal were preserved separately in 70% ethanol for later identification and counting. The immature stages of five ixodid tick species were collected from the elephant shrews, of which Rhipicephalus muehlensi was the most common. It has not been recorded previously on any species of elephant shrew. Three ixodid tick species were collected from the hedgehogs. Large numbers of adult Haemaphysalis colesbergensis, which has not been encountered previously on hedgehogs, were collected from these animals. Four-toed elephant shrews are good hosts of the larvae and nymphs of R. muehlensi, and Southern African hedgehogs are good hosts of adult H. colesbergensis
Показать больше [+] Меньше [-]Molecular characterisation of Mycobacterium bovis isolated from African buffaloes (Syncerus caffer) in Hluhluwe-iMfolozi Park in KwaZulu-Natal, South Africa
2011
Hlokwe, Tiny M(ARC-Onderstepoort Veterinary Institute ARC-Onderstepoort Veterinary Institute) | Jenkins, Akinbowale O(University of Pretoria Department of Veterinary Tropical Diseases) | Streicher, Elizabeth M(Stellenbosch University Stellenbosch University) | Venter, Estelle H(University of Pretoria Department of Veterinary Tropical Diseases) | Cooper, Dave(St Lucia Ezemvelo KZN Wildlife) | Godfroid, Jacques(Norwegian School of Veterinary Science Department of Food Safety and Infection Biology) | Michel, Anita L(University of Pretoria Department of Veterinary Tropical Diseases)
Bovine tuberculosis (BTB), a chronic disease of mammals caused by Mycobacterium bovis, is a threat to South African wildlife. It has been reported that African buffaloes (Syncerus caffer) are reservoir hosts of BTB in South African wildlife populations. This study reports on the molecular identification and typing of 31 M. bovis isolates collected between 1993 and 2008, mainly from buffaloes but also from two lions and a bush pig, in the Hluhluwe-iMfolozi Park (HiP) in KwaZulu-Natal. To study the dynamics of BTB in the buffalo populations, 28 M. bovis isolates from the HiP and epidemiologically related parks were characterised using regions of difference deletion analysis for species identification and spoligotyping, variable number of tandem repeats (VNTR), polymorphic G-C-rich sequences and IS6110 restriction fragment length polymorphism (RFLP) genotyping methods. At least three distinct M. bovis genotypes were found amongst HiP samples. The combination of VNTR typing (using a 16-loci panel) and IS6110 RFLP revealed the presence of three additional genetic profiles in individual buffaloes, demonstrating that the highest level of discrimination was achieved by these typing methods. One of the observed spoligotypes (SB0130) was dominant and represented 75% of isolates from buffaloes. A novel M. bovis spoligotype (SB1474), which is reported for the first time in this study, was observed in 14.3% of isolates from buffaloes. Based on the observed genetic relationships, the findings suggest independent introductions from at least three unrelated sources. These findings improve the knowledge regarding the diversity of circulating M. bovis strains in the HiP
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