Scan Science and Technology
Contact Leading Edge Experts & Companies
The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Anna E. Jolles – 1st expert on this subject based on the ideXlab platform
Toll-like receptor (TLR) diversity influences mycobacterial growth in African Buffalo.Tuberculosis, 2017Co-Authors: Nikki Le Roex, Anna E. Jolles, Brianna R. Beechler, Paul D. Van Helden, Eileen G. HoalAbstract:
Abstract Understanding the role of wildlife in the maintenance or spread of emerging infectious diseases is a growing priority across the world. Bovine tuberculosis (BTB) is a chronic, infectious disease caused by Mycobacterium bovis ( M. bovis ). BTB is widespread within game reserves in southern Africa, and within these ecosystems the primary wildlife host of this disease is the African Buffalo. We used a modified bacterial killing assay for mycobacteria to investigate the effect of Toll-like receptor (TLR) genetic diversity and demographic parameters on the ability of African Buffalo to restrict mycobacterial growth. Eosinophil count, time delay, bovine PPD response and avian PPD response were negatively correlated with mycobacterial growth. TLR6 diversity and the interaction of age group and sex were positively correlated with mycobacterial growth. Our results suggest that both demographic and individual immune parameters influence the ability to control mycobacterial infection in African Buffalo. TLR6 diversity is particularly interesting as this locus has also shown associations with BTB in cattle, suggesting that further research into the effects, selection and role of TLR6 variants in bovine tuberculosis will be productive.
enemies and turncoats bovine tuberculosis exposes pathogenic potential of rift valley fever virus in a common host African Buffalo syncerus cafferProceedings of The Royal Society B: Biological Sciences, 2015Co-Authors: Brianna R. Beechler, Vanessa O Ezenwa, Erin E Gorsich, Carrie A Manore, B Reininghaus, Dawn M Oneal, Anna E. JollesAbstract:
The ubiquity and importance of parasite co-infections in populations of free-living animals is beginning to be recognized, but few studies have demonstrated differential fitness effects of single infection versus co-infection in free-living populations. We investigated interactions between the emerging bacterial disease bovine tuberculosis (BTB) and the previously existing viral disease Rift Valley fever (RVF) in a competent reservoir host, African Buffalo, combining data from a natural outbreak of RVF in captive Buffalo at a Buffalo breeding facility in 2008 with data collected from a neighbouring free-living herd of African Buffalo in Kruger National Park. RVF infection was twice as likely in individual BTB+ Buffalo as in BTB− Buffalo, which, according to a mathematical model, may increase RVF outbreak size at the population level. In addition, co-infection was associated with a far higher rate of fetal abortion than other infection states. Immune interactions between BTB and RVF may underlie both of these interactions, since animals with BTB had decreased innate immunity and increased pro-inflammatory immune responses. This study is one of the first to demonstrate how the consequences of emerging infections extend beyond direct effects on host health, potentially altering the dynamics and fitness effects of infectious diseases that had previously existed in the ecosystem on free-ranging wildlife populations.
evaluation of the sensitivity and specificity of an enzyme linked immunosorbent assay for diagnosing brucellosis in African Buffalo syncerus cafferJournal of Wildlife Diseases, 2015Co-Authors: Erin E Gorsich, R G Bengis, Vanessa O Ezenwa, Anna E. JollesAbstract:
Brucellosis is a disease of veterinary and public health importance worldwide. In sub-Saharan Africa, where the bacterium Brucella abortus has been identified in several free-ranging wildlife species, successful disease control may be dependent on accurate detection in wildlife reservoirs, including African Buffalo (Syncerus caffer). We estimated the sensitivity and specificity of a commercial enzyme-linked immunosorbent assay (ELISA) (IDEXX Brucellosis Serum Ab test, IDEXX Laboratories, Westbrook, Maine, USA) for B. abortus based on a data set of 571 serum samples from 258 Buffalo in the Kruger National Park, South Africa. We defined a pseudogold standard test result as those Buffalo that were consistently positive or negative on two additional serologic tests, namely, the rose bengal test (RBT) and the complement fixation test (CFT). The ELISA’s cutoff value was selected using receiver operating characteristics analysis, the pseudogold standard, and a threshold criterion that maximizes the total sensitivity and specificity. Then, we estimated the sensitivity and specificity of all three tests using Bayesian inference and latent class analysis. The ELISA had an estimated sensitivity of 0.928 (95% Bayesian posterior credibility interval [95% BCI] = 0.869–0.974) and specificity of 0.870 (95% BCI = 0.836–0.900). Compared with the ELISA, the RBT had a higher estimated sensitivity of 0.986 (95% BCI = 0.928–0.999), and both the RBT and CFT had higher specificities, estimated to be 0.992 (95% BCI = 0.971–0.996) and 0.998 (95% BCI = 0.992–0.999), respectively. Therefore, no single serologic test perfectly detected the antibody. However, after adjustment of cutoff values for South African conditions, the IDEXX Brucellosis Serum Ab Test may be a valuable additional screening test for brucellosis in Kruger National Park’s African Buffalo.
Julius Beneoluchi Odili – 2nd expert on this subject based on the ideXlab platform
African Buffalo Optimization Algorithm for Tuning Parameters of a PID Controller in Automatic Voltage Regulators, 2020Co-Authors: Julius Beneoluchi Odili, Kahar M. N. M., Ahmad NoraziahAbstract:
In this paper, we present the African Buffalo Optimization (ABO) approach for the metaheuristic tuning of the Proportional, Integral & Derivative (PID) Controller parameters of Automatic Voltage Regulators in electrical power generation and transmission. ABO simulates the movement of African Buffalos as they migrate from place to place all over Africa in search of grazing pastures. The Buffalos use just two basic vocalizations, namely the waaa and the maaa to organize the entire herd in their migration and search for food a nd water. Though a recently-designed algorithm, the ABO has been effective and efficient in solving a number of search optimization problems. The highpoints of the ABO include its use of few parameters, constant interactions among the Buffalos and the deployment of the exploration and exploitations mechanisms of the algorithm in every iteration. The simulation outcome of the application of ABO to tune the parameters of a PID-Controller parameters of Automatic Voltage Regulators has been very competitive when compared similar outcomes of other metaheuristics tuners: BFO-PID, PSO-PID, GA-PID, PID-PSO, PID Tuner and ACO-PID.
African Buffalo Optimization Approach to the Design of PIDController in Automatic Voltage Regulator System, 2020Co-Authors: Julius Beneoluchi Odili, Kahar M. N. M.Abstract:
In the past few decades, researchers have focused so much attention on the application of bio-inspired techniques for solving real-life problems in science, engineering and industrial processes. This paper presents the African Buffalo Optimization (ABO) approach to tuning the Proportional, Integral and Derivative (PID) parameters of an Automatic Voltage Regulator. The ABO is a simulation of the movement of African Buffalos in the vast African landscape in search of lush grazing pastures using two basic sounds, namely the waaa and the maaa vocalizations. The ABO has so far been effective and efficient in providing solutions to a number of optimization problems as a result of its use of relatively fewer parameters, straightforward fitness function as well as regular communications using the star communication topology. Simulation results from the application of the ABO to tuning the parameters of an AVR has proven to be very competitive when compared with the results of other bio-inspired optimization techniques such as the GA-PID, ACO-PID, PSO-PID, BFO-PID, PID-PSO and PID Tuner.
Convergence Analysis of the African Buffalo Optimization Algorithm, 2020Co-Authors: Julius Beneoluchi Odili, Kahar M. N. M., Ahmad NoraziahAbstract:
This paper presents the convergence analysis of the newly-developed African Buffalo Optimization algorithm. African Buffalo Optimization is a simulation of the organizational skills of the African Buffalos using two
basic sounds: /waaa/ and /maaa/ as they transverse the African landscape in search of grazing pastures. The African Buffalo Optimization has proven to be quite successful since its development hence the need to examine its convergence behavior. The analysis of the convergence of Nature-inspired optimization algorithms is necessary to help researchers and practitioners understand the workings of the algorithms in the algorithms’ attempts at solutions. After a number of evaluations, this study discovered that the convergence of African Buffalo Optimization is a function of the population size, communication topology, parameter-set, landscape topology and the objective function being optimized.
Marinda C Oosthuizen – 3rd expert on this subject based on the ideXlab platform
tick borne haemoparasites in African Buffalo syncerus caffer from two wildlife areas in northern botswanaParasites & Vectors, 2015Co-Authors: Dewald Eygelaar, Ferran Jori, Nicola E Collins, Mokganedi Mokopasetso, Kgomotso P Sibeko, Ilse Vorster, Milana Troskie, Marinda C OosthuizenAbstract:
Background: The African Buffalo (Syncerus caffer) is a host for many pathogens known to cause economically important diseases and is often considered an important reservoir for livestock diseases. Theileriosis, heartwater, babesiosis and anaplasmosis are considered the most important tick-borne diseases of livestock in sub-Saharan Africa, resulting in extensive economic losses to livestock farmers in endemic areas. Information on the distribution of tick-borne diseases and ticks is scarce in Northern Botswana. Nevertheless, this data is necessary for targeting surveillance and control measures in livestock production at national level. Methods: In order to address this gap, we analyzed 120 blood samples from Buffalo herds for the presence of common tick-borne haemoparasites causing disease in livestock, collected in two of the main wildlife areas of Northern Botswana: the Chobe National Park (CNP, n = 64) and the Okavango Delta (OD, n = 56). Results: Analysis of the reverse line blot (RLB) hybridization assay results revealed the presence of Theileria, Babesia, Anaplasma and Ehrlichia species, either as single or mixed infections. Among the Theileria spp. present, T. parva (60%) and T. mutans (37%) were the most prevalent. Other species of interest were Anaplasma marginale subsp. centrale (30%), A. marginale (20%), Babesia occultans (23%) and Ehrlichia ruminantium (6%). The indirect fluorescent antibody test (IFAT) indicated 74% of samples to be positive for the presence of T. parva antibodies. Quantitative real-time PCR (qPCR) detected the highest level of animals infected with T. parva (81% of the samples). The level of agreement between the tests for detection of T. parva positive animals was higher between qPCR and IFAT (kappa = 0.56), than between qPCR and RLB (kappa = 0.26) or the latter and IFAT (kappa = 0.15). Conclusions: This is the first report of tick-borne haemoparasites in African Buffalo from northern Botswana, where animals from the CNP showed higher levels of infection than those from OD. Considering the absence of fences separating wildlife and livestock in the CNP and the higher levels of some parasite species in Buffalo from that area, surveillance of tick-borne diseases in livestock at the interface in the CNP should be prioritized.
phylogeny of theileria buffeli genotypes identified in the south African Buffalo syncerus caffer populationVeterinary Parasitology, 2014Co-Authors: Mamohale E Chaisi, Nicola E Collins, Marinda C OosthuizenAbstract:
Theileria buffeli/orientalis is a group of benign and mildly pathogenic species of cattle and Buffalo in various parts of the world. In a previous study, we identified T. buffeli in blood samples originating from the African Buffalo (Syncerus caffer) in the Hluhluwe–iMfolozi Game Park (HIP) and the Addo Elephant Game Park (AEGP) in South Africa. The aim of this study was to characterise the 18S rRNA gene and complete internal transcribed spacer (ITS1-5.8S-ITS2) region of T. buffeli samples, and to establish the phylogenetic position of this species based on these loci. The 18S rRNA gene and the complete ITS region were amplified from DNA extracted from blood samples originating from Buffalo in HIP and AEGP. The PCR products were cloned and the resulting recombinants sequenced. We identified novel T. buffeli-like 18S rRNA and ITS genotypes from Buffalo in the AEGP, and novel Theileria sinensis-like 18S rRNA genotypes from Buffalo in the HIP. Phylogenetic analyses indicated that the T. buffeli-like sequences were similar to T. buffeli sequences from cattle and Buffalo in China and India, and the T. sinensis-like sequences were similar to T. sinensis 18S rRNA sequences of cattle and yak in China. There was extensive sequence variation between the novel T. buffeli genotypes of the African Buffalo and previously described T. buffeli and T. sinensis genotypes. The presence of organisms with T. buffeli-like and T. sinensis-like genotypes in the African Buffalo could be of significant importance, particularly to the cattle industry in South Africa as these animals might act as sources of infections to naive cattle. This is the first report on the characterisation of the full-length 18S rRNA gene and ITS region of T. buffeli and T. sinensis genotypes in South Africa. Our study provides invaluable information towards the classification of this complex group of benign and mildly pathogenic species.