Immunoglobulin isotype response of Fasciola spp.infected sheep and cattle to defined Fasciola spp. antigens

Following the general introduction, chapter one, the thesis is divided into four chapters, covering literature review, materials and methods, results and discussion and conclusion.Fasciolosis is a liver fluke disease, caused by Fasciola hepatica in temperate regions and high altitude areas of the tropics and subtropics and by Fasciola gigantica, which is restricted to the tropics and subtropics. Liver flukes have a wide range of definitive hosts, including man and in particular domestic ruminants, but the various hosts are known to differ greatly in their resistance to infection with these parasites. For example sheep are considered susceptible to challenge infection while cattle develop resistance.F. hepatica secretes the enzyme cathepsin-Ll protease (Fh-cathepsin) which has a molecular weight (MWt) of 27 kDa. It is considered to have a functional role in parasite evasion of the host immune response, through cleavage of host immunoglobulin. The enzyme, glutathione s-transferase (GST) is of 27.8-29 kDa MWt, is also secreted by F. hepatica (Fh-GST) and is thought to be involved in the detoxification of exogenous (xenobiotic) and endogenous derived toxic compounds. Both enzymes form part of the fluke excretory/secretory (E/S) products and are of interest as they are considered as vaccine candidates against fasciolosis.This study investigated the immunoglobulin isotype responses of sheep and cattle, chronically infected with F. hepatica and F. gigantica, to defined the fluke antigens (F. hepatica E/S products (Fh-E/S) or F. gigantica E/S products (Fg-E/S), Fhxii cathepsin and Fh-GST). It was decided to study the immune response in chronically infected animals since immunity is considered to play a potentially more important role in chronic infection, than in acute infection, which is characterised by the death of the animal through anaemia and blood loss caused by the migrating flukes. Serum and faecal samples were collected weekly while the severity of the infections were defined using clinical, parasitological, haematological, biochemical and pathological parameters.Serum and faecal antibody (total Ig, IgGb IgM, IgG2 and IgA) responses to 24- 48 hour Fh-E/S and Fg-E/S, adult Fh-cathepsin and adult Fh-GST were determined by indirect Enzyme-linked Immunosorbent Assay (ELISA). The antigen recognition profile of the Fasciola spp. infected sheep and cattle to Fh-E/S and Fg-E/S was examined by sequential Western blotting.The general clinical and pathological pattern, combined with the parasitological, biochemical and haematological data confirmed that, in the main, the sheep and cattle were suffering from chronic fasciolosis. Lesions were most severe in sheep culled 11 to 20 weeks post infection (wpi) and calves with single infection, but culled 12 wpi, and those calves with challenge infection. Overall, the calves had very light infection and as a result they displayed a less severe chronic fasciolosis than that observed in sheep.A reduction in serum glucose levels was detected in F. hepatica and F. gigantica infected sheep from 3 wpi, especially in severely infected sheep. In contrast, there was an increase in serum P-hydroxybutyrate (P-HOB) levels in infected sheep, from about 6 to 15 wpi. And the extent of the rise in P-HOB levels was associated with the severity of the infection There was no serum glucose or P-HOB changes observed in infected calves. This was considered to be due to the very light fluke infection. Thus, it would appear from the serum glucose and P-HOB levels, that fasciolosis leads to energy deficiency (low glucose) and ketosis (increased b-HOB) especially noticeable in more heavily infected animals.There was an early (2-3 wpi) total Ig response to Fh-E/S and Fg-E/S, Fhcathepsin and Fh-GST in both F. hepatica infected sheep and cattle. Although there was an early (2-3 wpi) total Ig response to Fh-E/S and Fg-E/S, and Fh-GST by F. gigantica infected animals, there was a slight delay (7 wpi) noted in the response to Fh-cathepsin. The pattern of the IgGj response of cattle and sheep to these defined fluke antigens was similar to that of total Ig. In fact the serum isotype response was predominantly IgG]. The IgM response to Fh-E/S and Fg-E/S, Fh-cathepsin and Fh-GST was early in both species. In cattle the IgG2 and IgA responses to Fh-E/S and Fg-E/S were late and more pronounced (11 wpi and 19 wpi respectively) in contrast to sheep (2 wpi for both isotypes). The serum IgG2 and IgA isotype responses to Fh-cathepsin and Fh-GST followed the same pattern in cattle, however in sheep, responses to Fh-cathepsin was much less marked and a response to Fh-GST was not detected. A rise in total Ig and IgG, responses to Fh-E/S and Fg-E/S and Fh-cathepsin were detected following challenge infection in calves, but there was no increase in the response to Fh-GST. The dominance of the IgGj response in Fasciola spp. infected sheep and cattle suggests an associated Th2 response in both species. The late IgG2 response in cattle may suggest late Th, involvement in bovine cellular responses to Fh-E/S and Fg-E/S products.The detection of serum antibody responses to Fh-cathepsin and Fh-GST in F. gigantica infected sheep and cattle confirmed antigenic cross-reactivity. However this xiv cross-reactivity may be only partial, as suggested by the late total Ig and IgG, response to Fh-cathepsin by F. gigantica infected sheep and cattle. Comparison of the isotype responses to Fh-E/S and Fg-E/S products, Fh-cathepsin and Fh-GST suggest that there is very little difference between the response to Fh-E/S, Fg-E/S and Fh-cathepsin, however, there was a relatively poor response to Fh-GST in both sheep and cattle.Western blot analysis ofF. hepatica infected sheep serum identified antigens of 14 kDa from 2 wpi and 54, 79 and 134 kDa MW recognised later. In F. gigantica infected sheep antigens of 14, 88 and 152 kDa were identified from 7-9 wpi. There was a clear shift, at patency, in the antigen recognition pattern of cattle from higher (134 kDa for F. gigantica infection and 142 kDa for F. hepatica infection) to lower (60 kDa for both parasite species) but there was no clear antigenic shift observed in sheep. None of these antigenic molecules represented Fh-cathepsin (27 kDa MWt) or Fh-GST (27.9- 29 kDa MWt) used as antigens in the ELISA assay. The lower protein concentration of the E/S products used in this assay is, one possible reason for failure to detect these molecules.There was no faecal antibody response detected in cattle to any of the three defined antigens. This might have been due either to the light infections observed in cattle or to the larger volume of faecal material produced by cattle (i.e. dilution). There was an early (2 wpi) faecal total Ig response to Fh-E/S and Fg-E/S, Fh-cathepsin and Fh-GST in F. hepatica and F. gigantica infected sheep. In fact there was no difference in faecal antibody responses to the different antigens by either F. hepatica or F. gigantica infected sheep. The isotype response was mainly IgA while a slight IgG2 response could be detected in F. hepatica infected sheep. The total Ig and IgA responses XV to all three defined antigens in F. hepatica sheep was biphasic, in F. gigantica infection however the phases were less defined. The 1st phase (about 2-10 wpi) is considered a response to juvenile flukes antigens after oral infection and the second peak (13-17 wpi) is considered to be in response to antigens released by adult flukes in the bile duct.This study indicates that in serum, IgG( isotype responses predominate and in faeces IgA isotype responses to the three defined antigens predominate, suggesting preferentially stimulation of the Th2 T-cell subset in sheep and cattle fasciolosis. The late IgG2 response to F. hepatica and F. gigantica E/S and Fh-cathepsin in cattle may indicate a delayed Th, stimulation.In order to elucidate the different immune mechanisms operating in infected sheep and cattle there is need for more work on the cellular responses to Fasciola spp. as these may be related to resistance. There was antigenic shift in cattle at patency but not in sheep. The 60 kDa molecule being recognised by cattle after the antigenic shift. It is possible that this factor may be related to acquisition of resistance by cattle to secondary Fasciola spp. infectionFinally the findings relating to the glucose and b- HOB levels in infected sheep may prove helpful in experiments involved in the interaction between fasciolosis and the nutritional levels of Fasciola spp infected animals, of particular importance in young growing animals

THE BLENDING OF PARTICIPATORY RESEARCH AND QUANTITATIVE METHODS: WEALTH STATUS, GENDER AND THE ADOPTION OF IMPROVED FALLOWS IN ZAMBIA

Although there is increasing emphasis on targeting of improved technology towards poor and female farmers, few adoption studies assess the uptake of new practices by these groups in a comprehensive manner. In this study, community members used the wealth ranking method to identify the different wealth groups in their communities, to determine each household's wealth status, and to assess the association of wealth and different types of households with the planting of improved tree fallows, a practice for improving crop yields. There were no significant differences between the proportions of women and men planting improved fallows nor were there differences between single women and female heads of households who were married. There was some evidence of association between planting improved fallows and wealth. That 22% of the 'poor' group and 16% of the 'very poor' group were planting them suggests that there are no barriers preventing low-income households from doing so. Moreover, the proportion of females, poor, and very poor people planting improved fallows varied considerably among villages, suggesting that opportunities exist for increasing their use of technology. Whereas the use of mineral fertilizer is strongly associated with high-income, male farmers, improved fallows appear to be a gender-neutral and wealth-neutral technology. Poor farmers appreciate improved fallows because they permit them to substitute small amounts of land and labour for cash, their most scarce resource. Finally, the high degree of consistency among different key informants in classifying households among wealth groups confirmed the effectiveness and accuracy of the wealth ranking exercise.Adoption, agroforestry, Participatory research, Sesbania sesban, Research and Development/Tech Change/Emerging Technologies,

The role of women in the mining industry in Chaneng, Rustenburg, North West Province

Regardless of the region, mining has always been a male-dominated sector. There have been several initiatives that have worked to increase the involvement of women in the business, but females are still vastly underrepresented. The purpose of this study is to firstly provide a contextual point of view of the complexities that accompany the integration of women into the mining industry; secondly, to determine workplace relations struggles; and thirdly, to give a critical evaluation of the role that women are playing within the mining industry. This study intends to contribute to the sustainable deployment of women in the mining industry based on their contribution to the sector. Through qualitative data collection and analysis methods, the study interviewed 15 women with different racial, educational and marital backgrounds. The common factor among the study participants in the present study is that they are all mining industry workers. It should be noted that the study found women to play different roles within the sector and these roles cover areas such as leadership, inventors, researchers, training and awareness. Nonetheless, the roles that women in this study play are always impeded by the challenges and segregation associated with the mining industry which is considered an industry for menDevelopment StudiesM.A. (Development Studies

Is Climate Finance Helping Stabilise Food Prices in Sub-Saharan Africa?

This study explores the potential impact of climate finance (cf) on food prices in Sub-Saharan Africa (SSA) as climate change continues to create food scarcity and increase food prices. The study analyses data from 43 SSA countries between 2006 and 2018 using a panel fixed effect model with Driscoll-Kraay standard errors and methods of moments quantile regressions (MMQR). The findings indicate that countries in SSA that receive more cf, improve their fight against corruption, have good rainfall patterns, experience reduced extreme temperatures, have depreciated currencies, larger populations and higher GDP growth, reduce food imports, increase domestic food supply, and demonstrate high governance and social readiness are likely to experience stable or reduced food prices. Based on these results, the study recommends that SSA governments prioritise anticorruption efforts to earn donor trust and increase CF, ultimately leading to lower food prices in the sub-region. Further, the findings indicate that good rainfall patterns reduce food prices: this shows the need for SSA countries to invest in policies that lead to reliablewater supply as irrigation

Perceptions and acceptability of piloted Taenia solium control and elimination interventions in two endemic communities in eastern Zambia

Infections with Taenia solium cause significant public health and economic losses worldwide. Despite effective control tools, long‐term sustained control/elimination of the parasite has not been demonstrated to date. Success of intervention programs is dependent on their acceptability to local communities. Focus group discussions (FGDs) and questionnaires (QS) were conducted in two study communities in eastern Zambia to assess local perceptions and acceptance of two piloted intervention strategies: one targeting pigs only (‘control’ study arm), and one integrated human‐ and pig‐based (‘elimination’) strategy. QS (n = 227) captured data regarding participation in project activities, knowledge and perceptions of T. solium and of the interventional drugs used in the study. FGDs (n = 18) discussed perceived advantages and disadvantages of the interventions and of the project's delivery and value. QS data revealed 67% of respondents participated in at least one educational activity, and 80% correctly identified at least one disease targeted by the education. All elimination study arm respondents (n = 113) had taken the human treatment, and 98% intended to do so next time. Most (70%) indicated willingness to pay for future treatments (median 0.20 USD per dose). Of pig‐owning respondents, 11/12 (92%) had allowed their pigs to be treated/vaccinated and all intended to do so again next time. Four pig owners indicated willingness to pay 0.10–0.50 USD per dose of treatment or vaccine. FGD feedback revealed positive perceptions of interventions; people reported improved health in themselves and their pigs, and fewer cysticerci in pork. Latrine use, hand washing, meat inspection and proper cooking of pork had reportedly increased since the program's inception. Preliminary assessment indicates that the piloted intervention methods are generally acceptable to the communities. The reported willingness of many respondents to pay for the medications would contribute to the feasibility of long‐term, government‐led T. solium intervention programs in future

Six rounds of annual praziquantel treatment during a national helminth control program significantly reduced schistosome infection and morbidity levels in a cohort of schoolchildren in Zimbabwe

BackgroundThe World Health Organization recommends that schistosomiasis be treated through Mass Drug Administration (MDA). In line with this recommendation, Zimbabwe commenced a national helminth control program in 2012 targeting schoolchildren throughout the country for 6 years. This study, part of a larger investigation of the impact of helminth treatment on the overall health of the children, determined the effect of annual praziquantel treatment on schistosome infection and morbidity in a cohort of children during Zimbabwe's 6-year national helminth control program.Methodology/principal findingsA school-based longitudinal study was carried out in 35 sentinel sites across Zimbabwe from September 2012 to November 2017. The sentinel sites were selected following a countrywide survey conducted in 280 primary schools. Schistosoma haematobium was diagnosed using the urine filtration technique. Schistosoma mansoni was diagnosed using both the Kato-Katz and formol-ether concentration techniques. S. haematobium morbidity was determined through detection of macro and microhaematuria. A cohort of children aged 6-15 years old was surveyed annually before MDA and 6 weeks post treatment. Maximum treatment coverage reached 90% over the 6 rounds of MDA. At baseline S. haematobium infection prevalence and intensity were 31.7% (95% CI = 31.1-32.2) and 28.75 eggs/10ml urine (SEM = 0.81) respectively, while S. mansoni prevalence and intensity were 4.6% (95% CI = 4.4-4.8) and 0.28 eggs/25mg (SEM = 0.02). Prior to the 6th round of MDA, S. haematobium infection prevalence had reduced to 1.56% (pConclusionZimbabwe's helminth control program significantly reduced schistosome infection intensity and prevalence and urogenital schistosomiasis morbidity prevalence in a cohort of school-aged children, moving the schistosome prevalence in the children from moderate to low by WHO classification. These findings will inform the design of the country's next stage interventions for helminth control and eventual elimination

Responding to Cholera Outbreaks in Zimbabwe: Building Resilience over Time

Cholera is still a major cause of disease epidemics in sub-Saharan Africa (SSA). During the period January 2017–March 2018, 15 countries in the WHO African Region (AFR) reported cholera outbreaks of varying magnitudes. Zimbabwe has experienced cholera outbreaks dating as far back as 1971 with an unprecedented outbreak occurring in 2008/2009 when 60 of the 62 districts in the country were affected. The outbreak was declared over in May 2009 and by then, 98,592 cases and 4288 deaths had been reported. In Zimbabwe, outbreaks have occurred against a backdrop of a struggling economy and a weak health system. The role of a resilient health system in emergencies response is accentuated premised on experiences from the Ebola outbreak that largely affected three countries in West Africa. Amidst economic and persistent system wide challenges faced by Zimbabwe, preparedness and response capacity has been built over the years. This is evidenced by the rapid response and containment of the recent cholera outbreak. Skilled and equipped rapid response teams, strengthened surveillance and maintaining high alert, effective multisectoral collaboration and high level political engagement are among the critical elements that have built resilience

Progress on the development of rapid diagnostic tests for foodborne neglected zoonotic helminthiases : a systematic review

Background: Foodborne Neglected Zoonotic Helminths (FNZH) are parasites of both economic and public health importance. They include Taenia solium, Echinococcus granulosus sensu lato, Echinococcus multilocularis and Foodborne trematodes (FBT). FNZH are earmarked for major interventions for control, elimination and eradication. This systematic review highlights the progress towards development of rapid tests for the diagnosis of FNZH since 2010 when they were listed as neglected tropical diseases. Methodology: A systematic search was conducted in three databases, World of Science, Embase and PubMed using the same search phrase. The search produced 480 hits. Three studies from back referencing were included. Only 22 of these met the inclusion criteria. Data was extracted from these and presented qualitatively. Results: Twenty-five rapid diagnostic tests were found to have been developed since 2010, eight for diagnosis of T. solium infections, eight for echinococcosis and nine for FBT infections. The rapid tests for diagnosing T. solium infections included six antibody detecting and two antigen detecting tests. They constitute a combination among them, with some tests providing qualitative, others quantitative results. Similarly, seven out of the eight rapid tests developed for Echinococcus infections were antibody detecting tests save for one loop mediated isothermal amplification test. All of them were qualitative tests. For FBT infections, nine rapid tests were described; two antibody and one nucleic acid detecting test for diagnosis of Fascioliasis; three nucleic acid detecting tests for Opisthorchiasis; one antibody detecting test for Paragonimiasis; and for Clonorchiasis, one antibody and one nucleic acid detecting test. The FBT infection rapid tests were all qualitative in nature. Most of these tests have not undergone field evaluation in endemic areas where they will be used most. Conclusion: This review describes the development and evaluation of rapid diagnostic tests, while highlighting the need for in depth validations of the tools to determine how well they can perform in endemic areas

Prevalence of neurocysticercosis in people with epilepsy in the Eastern Province of Zambia

Zambia is endemic for Taenia solium taeniosis and cysticercosis. In this single-centered, cross-sectional, community-based study, the role of neurocysticercosis (NCC) as a cause of epilepsy was examined. People with epilepsy (PWE, n = 56) were identified in an endemic area using a screening questionnaire followed by in-depth interviews and neurological examination. Computed tomography (CT) was performed on 49 people with active epilepsy (PWAE) and their sera (specific antibody and antigen detection, n = 56) and stools (copro-antigen detection, n = 54) were analyzed. The CT scan findings were compared to a group of 40 CT scan controls. Of the PWE, 39.3% and 23.2% were positive for cysticercal antibodies and antigens, respectively, and 14.8% for coproantigens (taeniosis). Lesions highly suggestive of NCC were detected in 24.5% and definite NCC lesions in 4.1% of CT scans of PWAE. This compares to 2.5% and 0%, respectively, in the control CT scans. Using the Del Brutto diagnostic criteria, 51.8% of the PWAE were diagnosed with probable or definitive NCC and this rose to 57.1% when the adapted criteria, as proposed by Gabriel et al. (adding the sero-antigen ELISA test as a major criterion), were used. There was no statistically significant relationship between NCC, current age, age at first seizure and gender. This study suggests that NCC is the single most important cause of epilepsy in the study area. Additional large-scale studies, combining a community based prevalence study for epilepsy with neuroimaging and serological analysis in different areas are needed to estimate the true impact of neurocysticercosis in endemic regions and efforts should be instituted to the control of T. solium

Model of success : World Association for the Advancement of Veterinary Parasitology African Foundation (1997-2019)

No abstract available.http://www.jsava.co.za/index.php/jsavapm2020Veterinary Tropical Disease