70 research outputs found

    Spread in South Africa of the Oriental latrine fly Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae), an introduced species closely resembling Chrysomya bezziana Villeneuve

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    Chrysomya megacephala, also known as the Oriental latrine fly, is indigenous to south-east Asia. During the 1970's it successfully invaded Africa and South America, and more recently during the 1980's also established itself in the United States of America. Although the first specimens from South Arica were collected from the south-western Cape Province in 1978, no published data appears to exist on its subsequent spread or status in southern Africa. During May 1991 a specimen of C. megacephala was incidentally captured near Beaufort West, Cape Province, South Africa, which prompted re-examination of blow-flies captured in the Kruger National Park during 1984. In this way it was found that C. megacephala was already well established in the south-eastern Transvaal by mid-1984. Adult C. megacephala can easily be confused with C. bezziana and medical/veterinary entomologists and veterinarians should take note of the existence of this species and the fact that it is probably widespread throughout southern Africa at this state.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

    Large contractors in Africa : conundrums with malaria chemoprophylaxis

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    BACKGROUND : Despite high levels of naturally-acquired immunity (NAI) within local communities in malaria high transmission settings in Africa, such people often experience clinical disease during peak transmission months due to high parasite challenge. Major recruiters of unskilled labour in high-transmission malaria settings in Africa generally withhold chemoprophylactic medication from this large component of their labour force, which if administered during peak “malaria season” could reduce incidence of clinical malaria without unduly affecting NAI. COMMENTARY : Naturally acquired immunity confers protection against severe clinical disease and death, but does not prevent mild clinical disease and, therefore, still results in worker absence and worker debilitation. Evidence exists that NAI persists despite periodic parasite clearance and therefore provides opportunity for drug prophylaxis during peak transmission months, which contributes to broader malaria elimination objectives, community well-being, and reduced absence from work. Such chemoprophylaxis could be by way of standard daily or weekly supervised administration of prophylactics during peak transmission months, or occasional intermittent preventive treatment (IPT), all aimed at reducing parasite burden and clinical disease. However, challenges exist regarding compliance with drug regimens over extended periods and high parasite resistance to recommended IPT drugs over much of Africa. Despite withholding chemoprophylactics, most large companies nevertheless pursue social responsibility programmes for malaria reduction by way of vigorous indoor residual spraying and bed net provision. CONCLUSIONS : The lack of clear understanding regarding functioning of NAI and its role in malaria elimination campaigns, concerns about drug resistance and appropriate drug choice, lack of studies in the use of IPT in people other than pregnant women and small children, plus lack of guidance regarding drug options for IPT in the face of widespread resistance to sulfadoxine–pyrimethamine, means that large contractors in malaria endemic settings will likely continue to withhold malaria prophylactic drugs from locally-recruited workers, with adverse consequences on workforce well-being. Nevertheless, if the point of chemoprophylaxis is to reduce clinical malaria by way of reducing parasite challenge without significantly impacting NAI, then a comparable result can be achieved by implementation of effective vector reduction programmes which minimize parasite transmission but maintain NAI.http://www.malariajournal.comam2017UP Centre for Sustainable Malaria Control (UP CSMC

    African horsesickness epidemiology : five species of Culicoides (Diptera: Ceratopogonidae) collected live behind the ears and at the dung of the African elephant in the Kruger National Park, South Africa

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    During the culling of elephants (Loxodonta africana) at five sites in the Kruger National Park, South Africa, a total of 682 Culicoides of five species of the subgenus Avaritia were found live either behind the ears of elephants or attracted to the freshly disembowelled intestinal dung of elephants. The species are Culicoides tororoensis Khamala & Kettle, 1971; C. kanagai Khamala & Kettle, 1971; C. loxodontis Meiswinkel, 1992, and two undescribed species, i.e. Culicoides sp. #50 and Culicoides sp. #54 pale form (p.f.). Of 511 female midges found behind ears, 39,9% were nulliparous, 57,3% empty parous, 2,5% freshly bloodfed and 0,2% gravid. The age composition of this subpopulation indicates that the Culicoides were behind the ears to suck blood and, furthermore, would do so in broad daylight. The age composition of 171 Culicoides of three species attracted to dung was entirely different: 1,8% nulliparous, 14,6% empty parous, and 83,0% gravid, indicating that the great majority of midges captured at dung were about to oviposit or had just oviposited. Immediately after culling, light-traps were operated at two of the sites. Of 4 023 Culicoides of 21 species captured, 93% were of the same five species found on the ears and at the dung of elephants. Using these and other unpublished data pertaining to the rearing of these five Avaritia species from elephant dung over the past seven years, we broadly sketch the life cycle of these Culicoides, the first for any Afrotropical species of the genus. We also discuss the implications the close association between elephant and midge has for the dispersal and geographic distribution of the latter, and how it may influence the involvement of midges in the transmission of diseases such as African horsesickness. Owing to difficulties in identifying species of the subgenus Avaritia in the Afrotropical Region, the taxonomy of each of the five above-mentioned species is briefly appraised. Of the remaining 16 species (7%) captured in light-traps 15 (6%) belong to that sector of the genus Culicoides whose immature stages develop in groundwater habitats and include C. imicola, which comprised only 2% of the light-trap collections. The large disparity in the adult abundance patterns of the "dung" and "groundwater" species in the middle of dry bushveld, is probably the result of differences in host and larval habitat preferences, and is briefly discussed. Finally, the few reports extant on the wild-host preferences of Afrotropical Culicoides are reviewed. Five tables and five figures accompany the text.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

    Feeding habits and flight-range of blow-flies (Chrysomyia spp.) in relation to anthrax transmission in the Kruger National Park, South Afnca

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    Carrion-frequenting blow-flies (Chrysomyia albiceps and C. marginalis) were allowed 4 days of feeding on ³²P-orthophosphate-labelled blood or an Impala carcass (Aepyceros melampus) in the northern Kruger National Park, South Africa. The dispersal and density of fly faecal and discard droplets were then established using a Geiger-Counter, indicating that most droplets occurred between a height of 1 and 3 m on nearby leaves and twigs. This coincides with the preferred feeding height of kudu (Tragelaphus strepsiceros). During a previous anthrax epizootic kudu comprised 73,15 % of a total medium to large mammal mortality figure of 1054. Further analysis of mortality shows browsers to have been most severely affected, and it is suggested that this is correlated with feeding habits of these animals. Trapping also yielded radioactively labelled C. albiceps up to 32,5 km and C. marginalis up to 25 km from the isotope source.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

    Dispersal, density and habitat preference of the blow-flies Chrysomyia albiceps (Wd.) and Chrysomyia marginalis (Wd.) (Diptera: Calliphoridae)

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    16 000 Chrysomyia albiceps and 52 000 C. marginalis adults were radioactively labelled with ³²P-orthophosphate and released in the northern Kruger National Park, South Africa. After a 1-week dispersal period 69 baited blow-fly traps were placed in different habitat types and at varying distances around the release point. C. albiceps were subsequently found to have covered up to 37,5 km and C. marginalis 63,5 km, suggesting dispersal rates per day of 2,20 km and 2,35 km for the 2 species, respectively. Calculation of density using the Lincoln Index yielded estimates per hectare of 7,56 C. albiceps and 29,03 C. marginalis. Both species were trapped more numerously in forested environments than in open scrub, and both avoided arid scrubland.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.National Parks Board. CSIR.mn201

    Rediscovery of Haematobosca zuluensis (Zumpt), (Diptera, Stomoxyinae) : re-description and amended keys for the genus

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    BACKGROUND: Prior to this publication, the biting fly Haematobosca zuluensis (Zumpt, 1950) (Diptera, Muscidae, Stomoxyinae) was known only from a single male specimen collected in 1923 in Zululand, South Africa. Seven additional males were subsequently captured in the Kruger National Park of South Africa, one in 1984 and six in 1991, but remained unidentified until now. The genus includes species of considerable veterinary significance, but current keys for identification of species are misleading due to inadequate description of H. zuluensis. METHODS: External morphological features are described to enable species characterization, including intraspecific variability. RESULTS: This paper confirms the existence of H. zuluensis, expands its known range, provides a full description of males of the species, and gives an up to date set of keys for the 15 known species within the genus. Available records suggest that Haematobosca zuluensis is a low density species as yet known only from wildlife areas of South Africa. CONCLUSIONS: The additional specimens of H. zuluensis have enabled an improved description of the species and an improved set of keys to identify constituent members of the genus.LB conceived the need for the paper, undertook the microscopic and descriptive work as well as wrote the initial draft. ACP conducted the literature search, provided expert taxonomic editing and tracked down the location of the holotype. Both authors read and approved the final version of the manuscript.http://www.parasitesandvectors.com/content/5/1/267am2013ay201

    Seasonal abundance of carrion-frequenting blow-flies (Diptera : Calliphoridae) in the Kruger National Park

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    Monthly population fluctuations of carrion-frequenting blow-flies over a 24-month period were monitored using 2 carrion-baited traps in the southern Kruger National Park (KNP) and 3 in the northern KNP. All species displayed a clear seasonality. Chrysomyia marginalls and Chrysomyia albiceps were by far the most abundant. C. marginalis attained maximum abundance between November and March, with relatively low numbers present between May and September. C. albiceps maintained high population numbers between January and March in the northern KNP, with minimum numbers between May and August. In the southern KNP, C. albiceps became abundant from November to February, with low population levels between April and September. Although present only in relative low numbers, populations of Lucilia cuprina showed a clear increase in winter. Chrysomyia chloropyga, Chrysomyia putoria and Chrysomyia bezziana were trapped in significant numbers in the southern KNP, the latter 2 species reaching relative abundance in the warmer months, whereas C. chloropyga increased in cooler months from June to September. Graphic illustrations of monthly abundance are provided for all species.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

    Small mammals as hosts of immature ixodid ticks

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    Two hundred and twenty-five small mammals belonging to 16 species were examined for ticks in Free State, Mpumalanga and Limpopo Provinces, South Africa, and 18 ixodid tick species, of which two could only be identified to genus level, were recovered. Scrub hares, Lepus saxatilis, and Cape hares, Lepus capensis, harboured the largest number of tick species. In Free State Province Namaqua rock mice, Aethomys namaquensis, and four-striped grass mice, Rhabdomys pumilio, were good hosts of the immature stages of Haemaphysalis leachi and Rhipicephalus gertrudae, while in Mpumalanga and Limpopo Provinces red veld rats, Aethomys chrysophilus, Namaqua rock mice and Natal multimammate mice, Mastomys natalensis were good hosts of H. leachi and Rhipicephalus simus. Haemaphysalis leachi was the only tick recovered from animals in all three provinces

    Fleas and lice on scrub hares (Lepus saxatilis) in South Africa

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    A total of 380 scrub hares (Lepus saxatilis) from 5 localities, ranging from the north-eastern Transvaal to the eastern and the south-western Cape Province of South Africa, were examined for fleas and lice. Ctenocephalides felis damarensis was almost exclusively responsible for the flea infestations on hares at 4 of the 5 sites. At 4 localities the prevalence and abundance of this flea reached peaks between August and October and declined thereafter to their lowest levels between February and April. Its prevalence and abundance in the north-eastern Transvaal were not correlated with the breeding cycle of the hares in this region. The 2 louse species recovered, sometimes sympatrically, were Haemodipsus lyriocephalus and Haemodipsus setoni. Listrophorus leporicolus was the only mite species recovered.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Foundation for Research Development. South African Nature Foundation. Bayer Animal Health.mn201
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