296 research outputs found
Corrigendum: Forensic entomology research and application in southern Africa: A scoping review
Errors that appear in the Review Article by Tembe and Mukaratirwa are corrected here. Prof. Martin Villet (Director: Southern African Forensic Entomology Research Laboratory and Department of Zoology & Entomology, Rhodes University) is acknowledged for drawing the authors’ attention to these errors
A review of the epidemiology and control of gastrointestinal nematode infections in cattle in Zimbabwe
In this review, the main gastrointestinal nematodes infecting cattle in Zimbabwe and the epidemiological factors influencing their occurrence are reviewed and discussed. Nineteen gastrointestinal nematode species that belong to seven families have been found to occur in cattle in Zimbabwe. The main genera reported to date are Cooperia, Haemonchus, Trichostrongylus and Oesophagostomumand the dominant species are Cooperia pectinata, Cooperia punctata, Haemonchus placei and Trichostrongylus axei. The mixed infection by several species from the genera is the cause of parasitic gastroenteritis in cattle in Zimbabwe. Production and husbandry practices, season, host age and environment are considered to be the main factors that influence gastrointestinal nematode infection in cattle. The geographical distribution of the gastrointestinal nematodes is also reviewed in relation to the climatic conditions of the country. Various control options are discussed and how they are applicable to the Zimbabwean situation. Based on reports and existing data on the epidemiological features of the gastrointestinal nematode infection in cattle, practical control measures are critically reviewed and recommendations are made for a national control programme
Influence of <em>Calicophoron microbothrium </em>amphistomosis on the biochemical and blood cell counts of cattle
Tick-Bourne Pathogens of Potential Zoonotic Importance in the Southern African Region
The aim of this communication is to provide preliminary information on the tick-borne pathogens of potential zoonotic importance present in southern Africa, mainly focusing on their geographical distribution and host range, and to identify research gaps. The following tick-borne zoonoses have been reported to occur in southern Africa based mainly on case reports: Crimean–Congo haemorrhagic fever caused by Crimean–Congo haemorrhagic fever virus; ehrlichiosis caused by Ehrlichia ruminantium, Ehrlichia canis and Anaplasma phagocytophilum; babesiosis caused by Babesia microti; relapsing fever caused by Borrelia duttonii and rickettsioses caused by Rickettsia africae, Rickettsia aeschlimannii and Rickettsia conorii. The epidemiological factors influencing their occurrence are briefly reviewed
Stroma and extracellular matrix proteins in canine tumours
In this thesis, studies on temporal and spatial changes in stromal cells and extracellular matrix (ECM) molecules in canine gastrointestinal (GIT) tumours and canine transmissible venereal (CTVT) tumours are described. The mechanisms involved in the phenotypic transformation of fibroblasts to myofibroblasts, and ECM changes were investigated.
We found that the myofibroblast is the most common stromal cell in canine GIT epithelial tumours and most likely originated from pre-existing fibroblasts. Tenascin-C expression was absent in the normal mucosa of the stomach, but was expressed in the normal intestine with a gradual increase in intensity from the cryptal glands to the surface epithelium, suggesting tenascin-C was involved in shedding of enterocytes. Tenascin-C expression was increased in tumours compared to normal GIT mucosa. There was a strong co-localisation of tenascin-C and ?-SMA expressing myofibroblasts, suggesting that myofibroblasts may be responsible for tenascin-C secretion. Tenascin-C has been implicated in cell proliferation and adhesion by in vitro experiments. To find out whether this also occurs in vivo, the relationship between cell proliferation and tenascin-C expression in normal GIT mucosa and tumours was investigated. There was no relation between cell proliferation and tenascin-C expression in both normal gut and tumour tissues studied. The absence of a correlation between tenascin-C and cell proliferation suggests that the main function of tenascin-C in the GIT is anti-adhesion rather than proliferation.
Versican and hyaluronan are ECM components that are frequently increased in human tumours, and in vitro promote tumour progression. We analysed the histological distribution of versican and hyaluronan in colonic epithelial tumours. Versican expression was increased in the stroma of carcinomas and reduced in adenomas, and a significant correlation was observed between grade of the tumour and versican intensity and depth of invasion. Hyaluronan expression was increased in the stromal tissue of both adenomas and carcinomas. However, there was no correlation between hyaluronan stromal intensity and grade of the tumour or depth of tumour invasion. These results suggest that altered levels of both versican and hyaluronan in canine colonic tumours affect tumour progression. The role of stroma and ECM was continued in (CTVT), the only known naturally occurring tumour that can be transplanted as an allograft across MHC barriers. In CTVT, the number of stromal cell expressing ?-SMA (myofibroblasts) was significantly related to regressing tumours. The intensity of the stromal tenascin-C signal was significantly associated with regressing tumours. The intensity of stromal hyaluronan signal and tumour cell-associated hyaluronan were both significantly associated with progressing tumours. This suggests hyaluronan is involved in the tumour growth.
The specific mechanisms of how tumour and stromal cells interact to modulate the microenviroment are not clear. We investigated the mutual paracrine effects of colorectal tumour cells and stromal cells. We were able to show that canine stromal cells support tumour cell growth and differentiation. We also showed that tumour cells induce differentiation of stromal cells to myofibroblasts, and increased the synthesis of ECM molecules stromal cells via TGF-Ăź
Comparison of praziquantel efficacy at 40 mg/kg and 60 mg/kg in treating Schistosoma haematobium infection among schoolchildren in the Ingwavuma area, KwaZulu-Natal, South Africa
Background. The World Health Organization recommends praziquantel (PZQ) (40 mg/kg body weight) for treating schistosomiasis. However, drug failure has been reported, prompting use of 60 mg/kg, for which results have been inconsistent.Objectives. To compare the efficacy of PZQ 40 mg/kg and 60 mg/kg in treating schoolchildren infected with Schistosoma haematobium.Methods. The study was conducted during November 2017 - August 2018 in the Ingwavuma area, uMkhanyakude District, KwaZulu-Natal Province, South Africa. Children aged 10 - 15 years were screened for S. haematobium using a filtration technique. Infected children were randomly assigned to a dose of PZQ of 40 mg/kg or 60 mg/kg. Side-effects were recorded within 24 hours after treatment using questionnaires and direct observation. Four weeks after treatment, participants were retested for S. haematobium infection. Baseline and post-treatment mean egg counts were calculated. Cure rate (CR) and egg reduction rate (ERR) were used to determine PZQ efficacy, while repeated-measures analysis of variance determined the effect of both doses on infection intensity. A χ2 test was used to determine the association of side-effects with treatment, with a p-value ≤0.05.Results. Forty-three and 36 children were treated with PZQ 40 mg/kg and 60 mg/kg, respectively. The 40 mg/kg group had a CR of 79.0% and an ERR of 97.2%, and the 60 mg/kg group a CR of 83.0% and an ERR of 98.3%. The effect of dose on infection intensity was not significantly different between the two groups (p>0.05). Abdominal pains, dizziness and fatigue were common among children who received PZQ 40 mg/kg, while headache, dizziness and nausea were common in the 60 mg/kg group.Conclusions. The efficacy of PZQ at 60 mg/kg was similar to that at 40 mg/kg. A dose >40 mg/kg therefore does not add value in treating S. haematobium infection. Transient side-effects (mostly dizziness) were observed more in the 60 mg/kg group than in the 40 mg/kg group. We recommend continued use of 40 mg/kg body weight for treating schistosomiasis.
Surface composition and surface properties of water hyacinth (Eichhornia crassipes) root biomass: Effect of mineral acid and organic solvent treatment
The surface composition and surface properties of water hyacinth (Eichhornia crassipes) root biomass were studied before and after extraction with dilute nitric acid and toluene/ethanol (2/1, v/v) followed by ethanol, using Fourier Transform Infra-red (FT-IR) spectroscopy, thermogravimetric analysis, x-ray diffraction, scanning electron microscopy. FT-IR absorption bands were obtained at 3421, 2855, 1457 and 1035 cm-1 (O-H stretch, C-H vibration, C-H asymmetric deformation, and C-O stretch, respectively) and 1508, 1541 and 1559 cm-1 (all aromatic skeletal vibrations characteristic of lignin), as well as a C=O carboxylate stretch vibrational band at 1654 cm-1. Scanning electron microscopy confirmed the root biomass to be amorphous and not to have a strongly structured surface. The dilute mineral acid and organic solvent treatment increased crystallinity. Thermogravimetric analysis Studies show that the treated biomass are more thermally stable than the untreated biomass. Data are presented showing that dilute mineral acid and organic solvent treatment resulted in a decrease in the amount of lignin in the biomass. The implications of the decrease in the percentage of lignin on the adsorption of volatile polar organic solvents and non-polar n-alkane hydrocarbons is discussed. Key words: Water hyacinth, biomass, surface composition, Fourier Transform Infra-red (FT-IR) spectroscopy, scanning electron microscopy, x-ray diffraction spectroscopy, thermo gravimetric analysis
ADVANZ: Establishing a Pan-African platform for neglected zoonotic disease control through a One Health approach
Advocacy for neglected zoonotic diseases (ADVANZ) is a One Health Neglected Zoonotic Diseases (NZDs) project, funded by the European Commission through its 7th framework programme. The initiative aims at persuading decision makers and empowering stakeholders at local, regional, and international levels towards a coordinated fight against NZDs. ADVANZ is establishing an African platform to share experiences in the prevention and control of NZDs. The platform will compile and package existing knowledge or data on NZDs and generate evidence-based algorithms for improving surveillance and control with the ultimate aim of eliminating and eradicating these diseases. The platform will serve as a forum for African and international stakeholders, as well as existing One Health and NZD networks and harness and consolidate their efforts in the control and prevention of NZDs. The platform had its first meeting in Johannesburg, South Africa in March 2013
Bovine intestinal cellular responses following primary and challenge infections with <em>Calicophoron microbothrium</em> metacercariae
Epidemiological studies of parasitic gastrointestinal nematodes, cestodes and coccidia infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe
Between January 1999 and December 2000 faecal samples from 16 264 cattle at 12 dipping sites in the highveld and nine in the lowveld communal grazing areas of Zimbabwe were examined for gastrointestinal (GI) nematode and cestodes eggs, and coccidia oocysts. Strongyle larvae were identified following culture of pooled faecal samples collected at monthly intervals. The effects of region, age, sex and season on the prevalence of GI nematodes, cestodes and coccidia were determined. Faecal egg and oocyst counts showed an overall prevalence of GI nematodes of 43 %, coccidia 19.8 % and cestodes 4.8 %. A significantly higher prevalence of infection with GI nematodes, cestodes and coccidia was recorded in calves (P < 0.01) than in adults. Pregnant and lactating cows had significantly higher prevalences than bulls, oxen and non-lactating (dry cows) (P < 0.01). The general trend of eggs per gram (epg) of faeces and oocysts per gram (opg) of faeces was associated with the rainfall pattern in the two regions, with high epg and opg being recorded during the wet months. The most prevalent genera of GI nematodes were Cooperia, Haemonchus and Trichostrongylus in that order. Strongyloides papillosus was found exclusively in calves. Haemonchus was significantly more prevalent during the wet season than the dry season (P < 0.01). In contrast, Trichostrongylus was present in significantly (P < 0.01) higher numbers during the dry months than the wet months, while Cooperia and Oesophagostomum revealed no significant differences between the wet and dry season. These findings are discussed with reference to their relevance for strategic control of GI parasites in cattle in communal grazing areas of Zimbabwe
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