No description available.

Thesis (MSc (Paraclinical Sciences)--University of Pretoria, 2006. / Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Glucose was present in substantially greater concentrations in whole body extracts of fourth instar Aedes aegypti L. larvae than was trehalose; in contrast, trehalose was more abundant than glucose in haemolymph extracts. Preliminary studies suggested that infection of Ae. aegypti by the entomopathogenic digenean Plagiorchis elegans Rudolphi alters the carbohydrate metabolism of fourth instar larvae. Within 24 hours of cercarial penetration, total body extracts of infected fourth instar larvae exhibited decreased trehalase activity, increased trehalose-6-phosphatase activity, and an accumulation of trehalose in comparison to uninfected larvae. Concentrations of glucose, glycogen and lipids, and the activity of glycogen phosphorylase a were similar in extracts of infected and control larvae. The predominant fatty acids, in both control and infected larvae, were C 18:0, C 18:1 and C 18:3. There were no significant differences in the types and proportions of fatty acids found in control and infected larvae. Parasitic infection is discussed in terms of impaired trehalose metabolism.

Title from title page of PDF (University of Missouri--St. Louis, viewed March 23, 2010). Includes bibliographical references.

No description available.

Brucellosis is one of the neglected diseases in Nigeria. In Lagos, the commercial capital of Nigeria with about twenty one million people, a descriptive cross-sectional study was carried out in order to determine the sero-prevalence of brucellosis among people at risk in some selected abattoirs and secondary health care facilities (hospitals) in the state. Mixed sampling method was employed at the abattoir while convenient sampling method was used in sampling the respondents at the hospitals. Sera samples from three hundred and one (n=301) abattoir-based workers and traders; and one hundred and twenty one (n=121) hospital-based individuals which include people with febrile illnesses and blood donors were tested for brucellosis using Rose Bengal Plate test (RBPT), with indirect ELISA being used as a confirmatory test. Of the 301 abattoir-based workers and traders, 27 (8.97%) were sero-positive to the infection when Rose Bengal Plate test antigen was used. The twenty seven individuals consists of fifteen (15) butchers; four (4) veterinarians; two (2) meat transporters and bone/cow horn dealers each as well as one each of blood meal producer, abattoir engineer, water seller and meat supplier. When blood samples from the sero-positive individuals were subjected to ELISA, 3 (11.1%) were sero-positive to the brucellosis, while one is equivocal. These results confirm that agglutination observed on RBPT might be related to unknown cross-reactions and confirmation with a different test was necessary. None of the hospital-based respondents is sero-positive to the infection. The clinical signs significant for the infection in this study were fever, joint pain, lower backache, regular headache and miscarriage. Brucellosis awareness level among the respondents was very low. Data was analysed using (SPSS) version 20.0 at α0.05 significant level. The significant risk factors for human brucellosis according to this research are consumption of fura (unpasteurized milk) and wara (fresh cheese). The study revealed that brucellosis is not only an occupational disease but can also affect people who trade or live in proximity with infected animals. / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

Thesis (MScMedSc (Biomedical Sciences. Medical Biochemistry))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Mycobacterium bovis has a wide host range and infects many wild and domestic animal species as well as humans. African buffalo (Syncerus caffer) is considered to be a wildlife reservoir of M. bovis in certain environments in South Africa, such as in the Kruger National Park (KNP) and Hluhluwe-iMfolozi Park (HiP). A detailed pathological study was conducted on 19 African buffalos (Syncerus caffer) from a herd in the HiP in South Africa. The animals tested positive to the intradermal bovine tuberculin test and were euthanazed during a test-and-cull operation to decrease the prevalence of bovine tuberculosis (bTB) in the park. The superficial, head, thoraxic and abdominal lymph nodes and the lungs were examined grossly for presence of tuberculous lesions and were scored on a 1-5 scale for macroscopic changes. The gross lesions were examined histologically and scored I-IV according to a grading system used for bTB lesions in domestic cattle. Macroscopical lesions were limited to the retropharyngeal, bronchial, and mediastinal lymph nodes and the lungs. The most frequently affected lymph nodes were the bronchial (16/19) and mediastinal (11/19). All four grades of microscopic lesions were observed, although grade II lesions were the most frequent. Acid-fast bacilli were observed only rarely. Bovine tuberculosis was confirmed by PCR analyses. All animals were in good body condition and most of the lesions were in an early stage of development, indicating an early stage of the disease. The absence of lesions in the mesenteric lymph nodes and the high frequency of lesions in respiratory tract associated lymph nodes suggest that the main route of M. bovis infection in African buffalo is inhalatory rather than alimentary. This study presents a systematic evaluation and semiquantification of the severity and stages of development of tuberculous lesions in buffalo. The results may contribute to i) the understanding of the pathogenesis of the disease, ii) the evaluation of experimental models of M. bovis infection in Syncerus caffer, and iii) the interpretation of pathological data from vaccination trials. / AFRIKAANSE OPSOMMING: Mycobacterium bovis het ‘n wye reeks van gashere en dit infekteer verskeie wilde en mak dierespesies, sowel as mense. Die buffel (Syncerus caffer) word beskou as die wild reservoir van M. bovis in sekere dele van Suid Afrika, soos in die Kruger Nasionale Park (KNP) en Hluhluwe-iMfolozi Park (HiP). ‘n Breedvoerige patologiese studie is uitgevoer op 19 buffels afkomstig vanaf ‘n trop in die HiP in Suid Afrika. Die diere het almal positief getoets vir die intradermale beestuberkulin toets en is uitgesit tydens ‘n toets-en-slag operasie met die doel om die voorkoms van beestuberkulose (bTB) in die park te bekamp. Die oppervlakkige, kop, toraks en abdominale limfknope en longe is oorsigtelik ondersoek vir die teenwoordigheid van tuberkulose letsels en was ‘n punt toegeken op ‘n skaal van 1-5 vir die teenwoordigheid van makroskopiese veranderinge. Die opsigtelike letsels is histologies ondersoek en ‘n I-IV punt toegeken volgens die gradering wat gebruik word vir bTB letsels in beeste. Makroskopiese letsels was beperk tot die retrofaringeale, brongiale, en mediastinale limfknope en in die longe. Die brongiale (16/19) en mediastinale (11/19) limfknope was meestal geaffekteerd. Al vier grade van mikroskopiese letsels is gevind, alhoewel graad II letsels die volopste was. Suur-vaste basille is slegs selde waargeneem. Beestuberkulose is bevestig deur PKR analises. Al die diere was in ‘n goeie kondisie en meeste van die letsels was in ‘n vroeë stadium van ontwikkeling, wat aandui op ‘n vroeë fase van die siekte. Die afwesigheid van letsels in die mesenteriese limfknope en die hoë frekwensie van letsels in die lugweg geassosieerde limfkliere dui daarop dat the belangrikste roete van M. bovis infeksie in die buffel deur inaseming geskied eerder as deur opname in die spysverteringskanaal. Hierdie studie bied ‘n stelselmatige evaluering en semi-kwantifisering van die graad van erns en die stadia van ontwikkeling van tuberkulose letsels in buffels. Die resultate kan bydra tot i) die begrip van die patogenese van die siekte, ii) die evaluering van eksperimentele modelle van M. bovis infeksie in Syncerus caffer, en iii) die interpretasie van patologiese data van inentingsproewe.

Thesis (PhD)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: The emergence and re-emergence of viral human pathogens from wildlife sources in the recent past has led to increased studies and surveillance of wildlife for potentially zoonotic agents in order to gain a better understanding of the pathogens, their sources as well as events that may lead to viral emergence. Of the >1407 known human pathogens, 13% are classified as emerging or re-emerging, and 58% as zoonotic; 37% of the (re-)emerging and 19% of the zoonotic pathogens are RNA viruses, accounting for the majority of recently emerged infectious diseases with a zoonotic origin, such as HIV, Ebola, Hendra, Nipah, Influenza and SARS. This study focusses on potentially zoonotic viruses hosted by rodents (Muridae family), shrews (order previously known as Insectivora/Soricomorpha, now reclassified as Eulipotyphla) and bats (order Chiroptera). Rodents and bats represent the largest (~40%) and second largest (~25%) mammalian orders and both occur on every continent except Antarctica. Together, the three mammalian orders investigated represent the most relevant potential sources of new zoonoses. In this study I investigated the occurrence of astroviruses, arenaviruses, coronaviruses and hantaviruses in South African small mammal species belonging to the orders mentioned above. These viruses have either been implicated in recent emerging zoonotic events or are considered to have the potential to cause cross-species transmissions resulting in a zoonotic event. In the first part of the study specimens collected from various bat, rodent and shrew species were screened for viral sequences by broadly reactive PCRs; positive samples were characterised by sequencing and sequence analysis. A separate part of the study focussed on hantavirus disease in humans: a seroprevalance survey was conducted to determine the presence of hantavirus antibodies in the local population. Additionally, acutely ill patients with potential hantavirus disease were tested in an attempt to identify possible acute infections and define clinical hantavirus disease in South Africa. Screening of rodent and shrew specimens resulted in the identification of eight novel arenavirus sequences. Seven of the sequences are related to Merino Walk virus, a recently identified South African arenavirus, and the eighth sequence represents a novel lineage of Old World arenaviruses. Screening of bat specimens resulted in the identification of highly diverse novel astrovirus and coronavirus sequences in various South African bat species, including the identification of a viral sequence closely related to the recently emerged Middle East Respiratory Syndrome coronavirus. While the study did not identify hantavirus infections in any of the acutely ill patients, it found seroprevalences similar to those observed in Europe and West Africa. The results obtained highlight the importance of small mammals in the emergence of potential zoonoses and further reinforce the importance of viral surveillance of relevant wildlife species. Further in-depth studies of naturally infected reservoir host populations are required in order to gain a better understanding of virus-host dynamics and the events that lead to virus emergence. / German Research Foundation (DFG) (project number: KR1293/9-1/13-1) / The Polio Research Foundation and the NHLS Research / Harry Crossley Foundation, the Polio Research Foundation and Stellenbosch University for granting scholarships and bursaries for PhD.

PhD (Zoology) / Department of Zoology / An ever growing human population and accelerating land use change is associated with the loss of species and their ecosystem services. Agricultural intensification has led to a worldwide threat of extinction to about one quarter of all bat species, despite the valuable ecosystem service of pest control provided by bats. The decline in bat populations is mainly attributed to the loss or fragmentation of habitats, roost sites and feeding opportunities related to agricultural intensification and land use change. Therefore, proactive management of bat communities in agricultural landscapes is essential. South Africa is the world’s largest producer of macadamias and the industry continues to grow. This study gains insight into the habitat use and foraging behaviour of insectivorous bat species on a temporal and spatial scale, in and around macadamia orchards in order to advise management strategies on how to increase bat activity and, possibly, pest control. It also focuses on the preferences of artificial roost sites used by insectivorous bats in macadamia orchards. The diet of insectivorous bat species is especially difficult to study and the least invasive tool to gain information is the study of bat faecal pellets. In order to provide evidence for the consumption of pest insect species by bats and thus incentive to farmers for a more integrated pest management approach (IPM), this study explored molecular approach to insectivorous bat diet analyses using fragment analysis of bat faecal pellets with fluorescent-labelled species-specific primers (designed for the CO I gene). This study was conducted in the subtropical fruit growing area of Levubu, Limpopo province, South Africa between the towns Thohoyandou (22°59'03.7 S, 30°27'12.8 E) and Makhado/Louis Trichardt (23°03'03.6 S, 29°55'12.7 E). Levubu also accounts for the second highest production of macadamia in South Africa. An introduction to the order Chiroptera and into the relevance of insectivorous bat species to agriculture as well as the importance of a more integrated pest management approach (IPM) focusing on bats is provided in Chapter One. Bats were acoustically monitored and light traps were used to catch arthropods during one annual cycle. I sampled five macadamia orchards once a month from September 2015 to August 2016 and used GIS and R to analyse both the general bat activity and foraging bat activity of the two main foraging guilds (open-air/clutter edge guild) in different land use types as well as total bat activity with respect to arthropod abundances. As reported in Chapter Two, results show that the overall clutter edge guild activity (number of passes) decreased with macadamia and orchard (all other fruit) cover in the macadamia high season (December to end of May) and increased with bush cover and distance to settlements (potential roosts) in the macadamia low season (June to end of November). Open-air guild activity increased with fallow cover (uncultivated grassland with scattered trees and shrubs) in the high season. Foraging activity (feeding buzzes) of the clutter edge guild increased with bush cover over the whole year. Total activity (both guilds) increased with abundance of true bugs (Hemiptera), including the main macadamia pests, and bush cover. Macadamia cover has a negative effect on the activity of the clutter edge guild in the high season, with low activity in the orchard center (high cover), and activity increasing in a linear way with decreasing orchard cover at the orchard edge (low cover). These results suggest that the clutter edge guild prefers foraging close to the edges of the orchards rather than in the center, while the open-air guild prefers semi-natural habitats (fallow). When numbers of pest arthropods drop in the macadamia orchards, the natural land use type, bush, becomes a more important foraging habitat and thereby increased the activity of the clutter edge guild. From June 2016 to July 2017, I scanned 31 bat houses, mounted on poles on six macadamia orchards, for bats or any other occupants such as wasps, birds and bees. Twenty-one multichambered bat houses of three slightly different chamber designs were erected on poles, in sets of three. Additionally, five bat houses of the type ‘Rocket box’, four bat houses in sets of two (black and white) and one colony bat house were erected. Bats were counted and visually identified to family or species level. From December 2016 to end of March 2017, three IButtons were installed to record temperature variation between one set of three bat houses. As reported in Chapter Three, results show that the central bat house in the set of three and the black bat house in the set of two had a significantly positive effect on bat house occupancy. There was a significant difference in the mean temperature between the houses in the set of three, with a significant difference in temperature of 0.46°C between the central and the first bat house. The three bat houses erected in sets varied slightly in their chamber design, with the central bathouse having the most chambers (six), while the bat houses to either side had less chambers (four), set at an angle or straight. This and the insulation to either side by the other bat houses is assumingly what caused the central bat house to be on average warmer. The Yellow-bellied house bat (Scotophilus dinganii) was by far the most recorded and the only species observed to co-habitat a bat house with another animal species, in particular honeybees. The study might confirm assumptions in that the microclimate of bat houses, respectively their insulation, sun exposure and color appear to be important factors influencing bat house occupancy. The two preferred bat houses in our study were the black, in the set of black and white, as well as the central, and on average warmest bat house, in the set of three. I collected bat faecal pellets with two different methods between July 2015 and April 2017 to determine the prevalence of pest insects in faecal pellets. Eighteen of the bat houses (in sets of three) on three different farms and two Egyptian slit-faced bat (Nycteris thebaica) roosts were fitted with trays in order to collect pellets from those occupied by bats. I noted occupancy of bat houses to species or family level to keep disturbance minimal. Additionally, I collected pellets from individuals captured by means of mist nets and harp traps. Four of the main pest-insects; the two-spotted stinkbug (Pentatomidae: Bathycoelia distincta), the green vegetable bug (Pentatomidae: Nezara viridula), the macadamia nut borer (Tortricidae: Thaumatotibia batrachopa) and the litchi moth (Tortricidae: Cryptophlebia peltastica), were collected from pheromone traps or after scouting for primer development and optimisation. After extracting DNA from the bat faecal samples the target regions were amplified in a multiplex PCR and fluorescently labelled PCR amplicons were analysed and interpreted. In order to verify multiplex analyses results, all samples were amplified with all four sets of primers in plates and those that produced amplicons were purified and sequenced. As reported in Chapter Four, results show that fragment analyses yielded a total of 63 out of 103 samples tested positive for pest insect species (61%) with a total of 92 positive fragments. Primer specificity could be confirmed to 100% for the sequences obtained for Bathycoelia distincta (26/26) and Nezara viridula (12/12) primers but not for all sequences obtained fot Cryptophlebia peltastica (18/30) and Thaumatotibia batrachopa (1/14) primers. One sample showed no positive fragments but contained a positive sequence for N. viridula. Three samples tested positive for one pest-species fragment but contained a positive sequence for a second pest-species (B. distincta, T. batrachopa and C. peltastica). Adding four positive fragments and one additional positive sequence to the data. This means that sequences of pest insect species were obtained from 54 out of the 103 samples (55.6%) with a total of 73 pest insect sequences. For the high season (December to end of May) a total of 37 positive fragments for the four pest insect species and 24 negative samples were yielded and for the a low season (June to end of November) a total of 36 positive fragments and 15 negative samples. Looking at the pest consumption of the different bat species or families, our results show that all of them foraged on pest insect species. Whereas, all species and families except Myotis bocagii and Rhinolophus simulator (for which N<2) foraged on both the Lepidopteran and Hemipteran pest species. Therefore, all families of bats of which faecal pellets were analysed for this study (Molossidae, Nycteridae, Rhinolophidae and Vespertilionidae) foraged on one or more of the four pest insect species. In summary, Chapter Five concludes that natural and semi-natural vegetation promote bat activity in macadamia orchards, and potentially bats' provision of the ecosystem service of pest control. In times of accelerating land use change, remnants of natural vegetation are important refuges and need to be maintained or restored to conserve bat species and promote their ecosystem services. The study also shows that bat activity might be improved by adding roosting opportunities to orchards. Warm and well-insulated bat houses mounted freestanding on poles and in sets appeared to work best in northern South Africa. Further research on co-habitation of bat houses and displacement behaviour as well as the potential importance of altitude and distance to water is needed. All of the species or families of bats from which faecal pellets were collected have been confirmed to forage on at least one of the four pest insects and the bat species have shown to be much more generalist and presumably opportunistic feeders than previously assumed. Thus, this study provides incentive and advice to farmers for a more integrated pest management approach (IPM). / NRF