Patterns of energy flow in populations of the dominant insect consumers on Marion Island

Five insect species were identified as important primary consumers or decomposers in the terrestrial ecosystem of sub-Antarctic Marion Island. Patterns of energy flow in individuals ("life strategies") and populations (population energetics) of the five species were studied against the evolutionary templet of their respective microhabitats. Energy flow through populations of the five species was used for a quantitative description of energy flow through the primary consumer component of the Marion Island terrestrial ecosystem, while the life history and ecological attributes of the five species were compared against the background of past and present geological, climatological, evolutional and ecological processes in the sub-Antarctic. The insects are Embryonopsis halticel/a Eaton (Lepidoptera: Yponomeutidae); Ectemnorhinus similis (C. 0. Waterhouse) and E. marioni Jeannel (Coleoptera: Curculionidae); Pringleophaga marioni Viette (Lepidoptera: Tineidae) and Paractora dreuxi mirabilis Seguy (Diptera: Helcomyzidae). E. halticella is a host-specific folivore of the tussock grass Poa cookii, and dominates the herbivore guild on the island, while E. similis and E. marioni are polyphagous feeders of both angiosperms and bryophytes. P. marioni is a polyphagous detritivore and an important decomposer of plant litter. The kelp fly P. dreuxi mirabilis is the dominant decomposer of stranded kelp in the island's littoral zone. Herbivore populations (of E. halticella larvae and E. similis adults) assimilate less than 5 % of the annual net primary production at Marion Island. P. dreuxi mirabilis larval populations may assimilate up to 10 % of stranded kelp and play an important role in enhancing the microbial decay of wrack. The predominantly moss-feeding (E. marioni adults) and litter-feeding (P. marioni larvae) terrestrial insects do not contribute significantly to energy flow, but the latter species is the primary agent of nutrient mineralization and recycling in the terrestrial ecosystem. Each of the five species exhibits a combination of life history and ecological traits which is not satisfactorily explained by the r-K-A selection continuum, chiefly because of the intensity of resource restraints. Physiological economy is at a premium, and each species has evolved a distinct suite of adaptive characteristics which include slow growth, low metabolic rates, long life cycles, and deferred maturity. The lack of interspecific competition, and the general paucity of biotic restraints inherent in the sub-Antarctic Island situation, may be important factors in the evolution of the energy flow patterns exhibited by individuals and populations of sub-Antarctic insects.Thesis (PhD)--University of Pretoria, 1990.Zoology and EntomologyPhDUnrestricte

Development and validation of enzyme linked immunosorbent assays for detection of equine encephalosis virus antibody and antigen

The main purpose of this work was to develop rapid and reliable techniques that will prove valuable in epidemiological studies of equine encephalosis virus (EEV), the detection and identification of the virus for the laboratory confirmation of the clinical diagnosis and for the differential diagnosis between EEV and African horsesickness virus (AHSV). Two enzyme linked immunosorbent assays (ELISA) were developed. A polyclonal antibody-based, group-specific, indirect sandwich ELISA for the detection of EEV antigen was developed. The design of the assay was based on the methods currently used for the detection of AHSV. The cut-off value (absorbance of 0.15) was determined using populations of known negative specimens. No cross-reactions were recorded with viruses from other orbivirus serogroups or from other arboviruses. The assay proved to be sensitive and specific for the rapid detection of EEV and viral antigens in cell culture and mouse brain preparations. A polyclonal antibody-based, group-specific, competitive ELISA for the detection of antibodies to EEV was developed. No cross-reactions were recorded with the reference sera prepared against other orbivirus serogroups or other arboviruses. The cut-off (29.5% inhibition) value was determined using populations of known positive and negative sera. Analysis of the data showed the assay to be highly repeatable, sensitive and specific.Dissertation (MSc (Veterinary Science))--University of Pretoria, 2001.Veterinary Tropical Diseasesunrestricte

A scoping review of viral diseases in African ungulates

BACKGROUND: Viral diseases are important as they can cause significant clinical disease in both wild and domestic animals, as well as in humans. They also make up a large proportion of emerging infectious diseases. METHODS : A scoping review of peer-reviewed publications was performed and based on the guidelines set out in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. RESULTS : The final set of publications consisted of 145 publications. Thirty-two viruses were identified in the publications and 50 African ungulates were reported/diagnosed with viral infections. Eighteen countries had viruses diagnosed in wild ungulates reported in the literature. CONCLUSIONS : A comprehensive review identified several areas where little information was available and recommendations were made. It is recommended that governments and research institutions offer more funding to investigate and report viral diseases of greater clinical and zoonotic significance. A further recommendation is for appropriate One Health approaches to be adopted for investigating, controlling, managing and preventing diseases. Diseases which may threaten the conservation of certain wildlife species also require focused attention. In order to keep track of these diseases, it may be necessary to consider adding a “Wildlife disease and infection” category to the World Organisation for Animal Health-listed diseases.The Belgian Directorate-General for Development Cooperation (DGD) Framework Agreement project.https://www.mdpi.com/journal/vetscidm2022Veterinary Tropical Disease

Towards a yellow tulp vaccine : preliminary studies exploiting the potential for cross-reactivity with related bufadienolides

Poisoning by Moraea pallida Bak. (yellow tulp) is the most important of all cardiac glycoside induced toxicoses which collectively account for 33% and 10% of deaths in large and small stock due to plant poisoning, respectively, in the Republic of South Africa. This study was conducted to investigate the potential for developing a vaccine against epoxyscillirosidine, the toxin contained by yellow tulp. Epoxyscillirosidine was extracted, isolated, purified and confirmed using 13C NMR spectroscopy. Bufalin and proscillaridine were purchased and together with epoxyscillirosidine were coupled to BSA and KLH to render them immunogenic. The immunogens (4 mg/ml) were emulsified with an equal volume of Montanide ISA, as an adjuvant. Adult male New Zealand White rabbits (n=15) were randomly assigned to 5 equal groups. Rabbits in groups I, II, III and IV were immunized with proscillaridine-BSA, bufalin-BSA, epoxyscillirosidine-KLH and epoxyscillirosidine-BSA conjugates, respectively. Group V served as control where animals were administered BSA only. The rabbits were immunized on Days 0, 21 and 42 by intradermal injection of 0.1ml of the vaccine at four sites on the dorsum. Blood was collected prior to each vaccination and on Day 67. An ELISA was performed to determine antibody response. Antibodies were raised against proscillaridine, bufalin and epoxyscillirosidine. Furthermore, the antibodies synthesized by Group I and II rabbits also cross-reacted with epoxyscillirosidine. However, the degree of cross-reactivity was low. This may be enhanced by optimizing the vaccine to induce stronger antibody response. The antibodies will be evaluated to determine the neutralization efficacy against epoxyscillirosidine.Poster presented at the University of Pretoria, Faculty of Veterinary Science Faculty Day, September 07, 2017, Pretoria, South Africa.Includes bibliographical referencesab201

Development of a flow cytometric bead immunoassay and its assessment as a possible aid to potency evaluation of enterotoxaemia vaccines

Enterotoxaemia, an economically important disease of sheep, goats and calves, is caused by systemic effects of the epsilon toxin produced by the anaerobic bacterium Clostridium perfringens type D. The only practical means of controlling the occurrence of enterotoxaemia is to immunise animals by vaccination. The vaccine is prepared by deriving a toxoid from the bacterial culture filtrate and the potency of the vaccine is tested with the in vivo mouse neutralisation test (MNT). Due to ethical, economic and technical reasons, alternative in vitro assays are needed. In this study an indirect cytometric bead immunoassay (I-CBA) was developed for use in vaccine potency testing and the results were compared with those obtained using an indirect enzyme-linked immunosorbent assay (I-ELISA) and the MNT. Sera were collected from guinea pigs immunised with three different production batches of enterotoxaemia vaccine and the levels of anti-epsilon toxin antibodies were determined. Although the intra- and inter-assay variability was satisfactory, epsilon antitoxin levels determined by both the I-ELISA and indirect cytometric bead immunoassay (I-CBA) tests were higher than those of the MNT assay. In contrast to the MNT, all of the serum samples were identified as having antitoxin levels above the required minimum (not less than 5 U/mL). These results indicate that the respective in vitro tests in their current formats are not yet suitable alternatives to the in vivo MNT. The growing demand for a more humane, costeffective and efficient method for testing the potency of enterotoxaemia vaccines, however, provides a strong impetus for further optimisation and standardisation of the I-CBA assay but further analytical research is required.Onderstepoort Biological Products (OBP)http://www.jsava.co.zaam201

The prevalence of Culicoides spp.in 3 geographic areas of South Africa

The seasonal abundance of Culicoides midges, the vector of Bluetongue and African horse sickness viruses (BTV/AHSV) and the presence of viruses in midges were determined in 3 geographic areas in South Africa. In the Onderstepoort area, more than 500,000 Culicoides midges belonging to 27 species were collected. Eighteen midge species were collected throughout Winter and the presence of AHSV and BTV RNA in midges was detected using real time reverse transcription quantitative polymerase chain reaction. The nucleic acid of AHSV was found in 12 pools out of total pools of 35 Culicoides. Twenty‑five Culicoides species were detected in the Mnisi area. The RNA of BTV was detected in 75.9% of the midge pools collected during Winter and 51.2% of those collected during Autumn. Antibodies for BTV were detected in 95% of cattle sampled using a competitive enzyme‑linked immunosorbent assay (cELISA). The dominant species in these 2 areas was Culicoides imicola. Eight Culicoides species were collected in Namaqualand. Culicoides imicola represented the 0.9% and Culicoides bolitinos the 1.5% of total catches, respectively. Antibodies for AHSV were detected in 4.4% of 874 equines tested using an indirect ELISA. Results showed that transmission of AHSV and BTV can carry on throughout Winter and the outbreak may begin as soon as Culicoides populations reach a certain critical level. [Abstract] I Culicoides sono noti vettori del virus della Bluetongue (BTV) e del virus della Peste equina africana (AHSV). Il lavoro riporta i risultati sull'abbondanza stagionale di Culicoides e sulla presenza di BTV e AHSV in diversi vettori, in tre aree geografiche del Sudafrica. Nell'area di Onderstepoort sono stati individuati più di 500.000 esemplari di Culicoides appartenenti a 27 specie diverse. Durante la stagione invernale sono state individuate 18 specie. Frammenti di RNA di AHSV e BTV sono stati rilevati mediante specifiche RT-qPCR. L'RNA del virus AHSV è stato individuato in 12 pool di Culicoides su 35 esaminati. Nell'area di Mnisi sono state identificate 25 specie di Culicoides. L'RNA di BTV è stato rilevato nel 75,9% dei pool di Culicoides catturati durante la stagione invernale e nel 51,2% di quelli catturati durante la stagione autunnale. Anticorpi contro BTV sono stati osservati nel 95% dei sieri prelevati da bovini dell'area di Mnisi ed esaminati con il metodo c‑ELISA. La specie dominante in queste due aree è risultata Culicoides imicola. Nella regione di Namaqualand sono state individuate otto specie, C. imicola ha rappresentato lo 0,9% delle specie catturate e Culicoides bolitinos l'1,5%. Anticorpi contro il virus AHSV sono stati individuati mediante ELISA nel 4,4% degli 874 equini esaminati. I risultati ottenuti hanno dimostrato che in Sudafrica la trasmissione di BTV e AHSV può continuare durante la stagione invernale mentre, con ogni probabilità, si ha la comparsa dei primi focolai quando le diverse popolazioni di Culicoides raggiungono un livello riproduttivo critico

New skills training for final year vet students serves the agricultural needs of South Africa

In 2018 the Faculty of Veterinary Science at Onderstepoort embarked on enriching the skills base of newly qualified veterinarians by developing a one-week training course to diagnose bovine tuberculosis and brucellosis. These are important state controlled diseases of cattle which also affect many wildlife species (I.e. buffalo, lions). In 2019 this training course has been well established and we look forward to being able to present it to external trainees in 2020.Originally published as HTML file, converted to PDF with Adobe Acrobat 9 Pro Version 9.0.0.News articles with colour photos about what's happening at the Faculty of Veterinary Science, University of Pretoria.ab201

Quantitative anti-PA IgG ELISA : assessment and comparability with the anthrax toxin neutralization assay in goats

BACKGROUND: Presently, few data exist on the level and duration of anti-protective antigen (PA) IgG in vaccinated livestock. Various adaptation of enzyme-linked immunosorbent assays (ELISAs) have been developed in studies to assess immune response following vaccination, albeit mostly in laboratory rodent models. The quantitative anti-anthrax IgG ELISA in this study describes a method of enumerating the concentration of anti-PA specific IgG present in sera of immunized goats, with the aid of an affinity-purified caprine polyclonal anti-anthrax PA-83 IgG standard. This was compared with the anthrax toxin neutralization assay (TNA) which measures a functional subset of toxin neutralizing anti-PA IgG. RESULTS: The measured concentrations obtained in the standard curve correlated with the known concentration at each dilution. Percentage recovery of the standard concentrations ranged from 89 to 98% (lower and upper asymptote respectively). Mean correlation coefficient (r2) of the standard curve was 0.998. Evaluation of the intra-assay coefficient of variation showed ranges of 0.23-16.90% and 0.40-12.46% for days 28 and 140 sera samples respectively, following vaccination. The mean inter-assay coefficient of variation for triplicate samples repeated on 5 different days was 18.53 and 12.17% for days 28 and 140 sera samples respectively. Spearman’s rank correlation of log-transformed IgG concentrations and TNA titres showed strong positive correlation (rs = 0.942; p = 0.01). CONCLUSION: This study provides evidence that an indirect ELISA can be used for the quantification of anti-anthrax PA IgG in goats with the added advantage of using single dilutions to save time and resources. The use of such related immunoassays can serve as potential adjuncts to potency tests for Sterne and other vaccine types under development in ruminant species. This is the first report on the correlation of polyclonal anti-anthrax PA83 antibody with the TNA in goats.The Deutsche Forschungsgemeinschaft (German Research Foundation)http://www.biomedcentral.com/1746-6148/9/265am2014ab201

Ethical dilemmas when dealing with doctor Google and the importance of patient education

A 55 year old female patient presented for dental treatment. Her attending clinician immediately noted that since her first visit some days previously she had shaved her head, revealing a severe rash on her right forehead and scalphttp://www.sada.co.zaam2020Prosthodontic

Updated distribution and host records for the argasid tick Ornithodoros (Pavlovskyella) zumpti : a potential vector of African swine fever virus in South Africa

African swine fever virus (ASFV) causes a lethal and contagious disease of domestic pigs. In South Africa, the virus historically circulated in warthogs and ornithodorid ticks that were only found in warthog burrows in the north of the country. Regulations implemented in 1935 to prevent transfer of infected animals or products to the south initially proved effective but from 2016 there have been outbreaks of disease in the south that cannot be traced to transfer of infection from the north. From 1963 there were widespread translocations of warthogs to the south, initially from a source considered to be free of ornithodorid ticks. We undertook to determine whether sylvatic circulation of ASFV occurs in the south, including identification of potential new vectors, through testing extralimital warthogs for antibody and ticks for virus. Results of testing warthogs for antibody and other species of ticks for virus will be presented separately. Here we report finding Ornithodoros (Pavlovskyella) zumpti ticks in warthog burrows for the first time. This occurred in the Eastern Cape Province (ECP) in 2019. Since African swine fever was recognised in the ECP for the first time in 2020 and outbreaks of the disease in domestic pigs continue to occur there, priority should be given to determining the distribution range and vector potential of O. (P.) zumpti for ASFV.The project was supported by a research contract from Kansas State University and a grant was awarded by the South African Agricultural Sector Education and Training Authority (AgriSETA) to the Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria (UP) as well as National Bio and Agro-defense Facility (NBAF) Transition funds from the State of Kansas, the National Institute of General Medical Sciences (NIGMS) of the National Institutes of Health and the Department of Homeland Security Center of Excellence for Emerging and Zoonotic Animal Diseases.http://www.ojvr.orgam2022Veterinary Tropical Disease