Developing and evaluating comprehensive multiplex peptide array for serological diagnostic and surveillance of infectious disease in Zimbabwe.

Doctoral Degree. University of KwaZulu-Natal, Durban.Introduction: Peptides that mimic B-cell linear epitopes may be used as biomarkers for the diagnosis and surveillance of diseases. Peptide microarray technology provide rapid and high-throughput immunoassay platforms, for the simultaneous of identification of B-cell linear epitopes. In this framework, a peptide microarray was designed for the integrated surveillance of infectious diseases endemic in Zimbabwe. The peptide microarray was evaluated against peptides derived from Ascaris lumbricoides, Necator americanus, Shistosoma haematobium, Schistosoma mansoni, Trichuris trichiura, Bacillus anthracis, Mycobacterium leprae, Wuchereria bancrofti, Rabies lyssavirus, Chlamydia trachomatis, Trypanosoma brucei and severe acute respiratory syndrome coronavirus (SARS-CoV-2). Methods: Published peptides were retrieved from the Tackling Infection to Benefit Africa infectious diseases epitope microarray. Novel peptides were predicted using ABCpred. The peptide microarrays were printed in a laser based approach. IgG and IgM reactivity against the derived peptides were evaluated using peptide microarray immunoassays. Positive response was defined as fluorescence intensity ≥ 500 relative fluorescence units. Immunodominant peptides were identified using heat maps and bar graphs reflecting the obtained fluorescence signal intensities. Receiver Operating Characteristic (ROC) analysis and Mann-Whitney-U test were performed to determine the diagnostic validity of the peptides. Results: Species-specific responses with at least one peptide derived from each NTD pathogen were observed. The reactive peptides included; for S. haematobium, XP_035588858.1-206-220 and XP_035588858.1-206-220 immunodominant for IgG and IgM respectively, for S.mansoni, P20287.1-58-72 immunodominant for both antibodies and for T. trichuria, CDW52482.1-326-340 immunodominant for IgG and CDW57769.1-2017-2031 and CDW57769.1-1518-1532 immunodominant for IgM. For SARS-CoV-2 derived peptides, 4 (QTH34388.1- 1-14, QRU89900.1-41-54, QTN64908.1-136-149 and QLL35955.1-22-35) showed reactivity against IgG. Four peptides (QRU89900.1-41-54, QSM17284.1-76-89, QTN64908.1-136-149 and QPK73947.1-8-21) also showed reactivity against IgM. The SARS-CoV-2 reactive peptide were derived from the membrane glycoprotein and nucleocapsid protein. Conclusion: Species-specific sero-reactivity was indicative of exposure to the different NTDs parasites antigens. Multiplex peptide microarrays are a valuable tool for integrated NTDs surveillance and for screening parasites exposure in endemic areas. In silico peptide prediction and peptide microarray technology may provide a powerful platform for the discovery of SARS-CoV-2 B-cell epitopes. Nhanganyaya: Peptides akafanana nema B-cell linear epitopes akakosha nekuti anogona kushandiswa kuongorora kuti munhu anechirwere here nekurakidza kutenderera kwezvirwere munharaunda . Peptide microarray inotibatsira kutsvaka ma B-cell linear epitopes nekukasika panguva imwe. Nekuda kweizvozvo, peptide microarray yakagadzirirwa kuti tiongorore zvirwere zvinotapukira munyika yeZimbabwe. Iyo peptide microarray yakaongororwa mashoja emuviri anorwisa zvirwere zvinosanganisira chirwere cheelephantiasis, bhiraziya, chirwere chemakonye emudumbu (intestinal worms), chirwere chemaziso chetrachoma, chirwere chemapere mbudzi, chirwere cherabis chirwere che COVID-19 nechirwere cheanthrax. Maitiro: Mamwe mapeptides akawanikwa kubva ku Tackling Infection to Benefit Africa infectious diseases epitope microarray. Mapeptides matsva akawandikwa pachishandiswa chirongwa cheABCpred. Ma peptide microarray akagadzirwa ku Germany nemhando ye laser printer tekinoroji. Masoja emumiviri anoti IgG ne IgM ezvirwere zvambotaurwa akarongororwa tichishandisa peptide microarray tekinoroji. Zvakabuda muwongororo: Takaona kuti vanhu vemuZimbabwe vane masoja emuviri anokwanisa kurwisa mapeptides anowanikwa pahosha dzinokonzeresa zvirwere zvinosanganisira chirwere cheelephantiasis, bhiraziya, chirwere chemakonye emudumbu (intestinal worms), chirwere chemaziso chetrachoma, chirwere chemapere mbudzi, chirwere cherabis chirwere che COVID-19 nechirwere cheanthrax. Takaona zvakare kuti peptide microarray tekinoroji inokwanisa kushandiswa kuongorora zvirwere zvakawanda panguva imwe

Effect of traditional processing methods on protein digestibility and chemical constituents in seeds of Bauhinia petersiana

Background: Antinutritional factors present in food may reduce the bioavailability of nutrients and cause harmful effects to human health. Aims: The aim of this study was to determine the effect of traditional processing methods on protein digestibility, nutrient and antinutrient constituents of seeds of Bauhinia petersiana. Subjects and Methods: The seeds were processed by soaking in water, boiling or roasting before analyzing protein digestibility, nutrient and antinutrient compositions. Results: Soaking resulted in no significant changes in the content of moisture, protein, fiber, phytates and trypsin inhibitor activity and significant reductions in fat, ash and tannins. Roasting resulted in no significant change in the content of moisture, ash, protein, and fiber and significant reductions in fat, phytates and trypsin inhibitor activity. Boiling resulted in a significant increase in the content of both protein and fiber and reduction in fat, ash, tannins, phytates and trypsin inhibitor activity. Mineral content of zinc, magnesium and calcium was not changed by soaking, roasting or boiling of the seeds. The calculated phytate: zinc molar ratios for both the raw and processed seeds were greater than 10, the limit for optimal absorption of zinc in the small intestine whereas phytate: iron molar ratios were less than 14, the limit for optimum absorption of iron in the intestines. In vitro digestibility of proteins in the seeds was increased when the seeds were soaked, roasted or boiled. Conclusions: Boiling the seeds of B. petersiana before consumption would effectively remove undesirable antinutrients while maintaining the nutrient content of the seeds and improving digestibility of proteins

Multiplex peptide microarray profiling of antibody reactivity against neglected tropical diseases derived B-cell epitopes for serodiagnosis in Zimbabwe

INTRODUCTION: Peptides (B-cell epitopes) have broad applications in disease diagnosis and surveillance of pathogen exposure. In this framework, we present a pilot study to design and produce a peptide microarray for the integrated surveillance of neglected tropical diseases. The peptide microarray was evaluated against peptides derived from Ascaris lumbricoides, Necator americanus, Schistosoma haematobium, Schistosoma mansoni, Trichuris trichiura, Bacillus anthracis, Mycobacterium leprae, Wuchereria bancrofti, Rabies lyssavirus, Chlamydia trachomatis and Trypanosoma brucei. METHODS: S. haematobium was diagnosed using the urine filtration technique. S. mansoni, A. lumbricoides, N. americanus and T. trichiura were diagnosed using the Kato Katz and formal ether concentration techniques. Immunogenic peptides were retrieved from the Tackling Infection to Benefit Africa infectious diseases epitope microarray. Further peptides were predicted using ABCpred. IgG and IgM reactivity against the derived peptides were evaluated using peptide microarray multiplex immunoassays. Positive response was defined as fluorescence intensity ≥ 500 fluorescence units. Immunodominant peptides were identified using color-coded heat maps and bar graphs reflecting the obtained fluorescence signal intensities. Receiver Operating Characteristic analysis and Mann-Whitney-U test were performed to determine the diagnostic validity of the peptides. RESULTS: Species-specific responses with at least one peptide derived from each NTD pathogen were observed. The reactive peptides included; for S. haematobium, XP_035588858.1-206-220 and XP_035588858.1-206-220 immunodominant for IgG and IgM respectively, for S. mansoni, P20287.1-58-72 immunodominant for both antibodies and for T. trichiura, CDW52482.1-326-340 immunodominant for IgG and CDW57769.1-2017-2031 and CDW57769.1-1518-1532 immunodominant for IgM. According to ROC analysis most of the peptides selected were inaccurate; with AUC < 0.5. Some peptides had AUC values ranging from 0.5 to 0.5875 for both IgM and IgG suggesting no discrimination. CONCLUSION: Multiplex peptide microarrays are a valuable tool for integrated NTDs surveillance and for screening parasites exposure in endemic areas. Species sero-reactivity observed in the study maybe indicative of exposure to the different NTDs parasites. However, although peptides with the least cross reactivity were selected there is need to validate the sero-reactivity with recombinant antigens and immune-blotting techniques such as western blotting

Effect of schistosoma haematobium infection on the cognitive functions of preschool age children and benefits of treatment from an endemic area in Zimbabwe

BACKGROUND: Schistosomiasis is known to affect the cognitive functions of children, however, but there is paucity of information on its impact on early childhood development in developing countries where the disease is endemic. This study aimed at determining the effects of schistosomiasis due to Schistosoma haematobium on early childhood development in children below 5 years old from Murewa District, Zimbabwe, including the benefits of treatment. METHODS: Preschool age children (PSAC) under the age of 5 years were screened at baseline and at 6 months post-treatment for S. haematobium infections diagnosed using the urine filtration method. Cognitive domains were assessed using the Griffith Mental Developmental Scales III on 136 PSAC. Multivariate logistic regression was used to determine the level of association between S. haematobium infection and performance in the cognitive domains adjusting for confounding factors (i.e. nutrition, hemoglobin levels, gender and age). Median Development Quotient scores of each cognitive domain at baseline and at 6 months post-treatment were compared and quantified. RESULTS: After adjusting for confounding factors, PSAC infected with S. haematobium had greater odds of having lower scores in the Foundation of Learning Domain (OR = 3.9, p = 0.008), Language and Communication Domain (OR = 3.2, p = 0.017), Eye-Hand Coordination Domains (OR = 10.7, p = 0.001), Personal-Social-Emotional Domain (19.3, p = 0.001) and in the Overall General Development Domain (7.2, p = 0.011). Improvement of cognitive performance was observed at 6 months post treatment in the following Domains; Language and Communication Domain (p = 0.003), Eye-Hand Coordination Domain (p = 0.02) and General Development Domain (p = 0.006). CONCLUSION: The study showed that S. haematobium infection in PSAC is associated with lower cognitive scores in the Foundation of Learning, Language and Communication, Eye-Hand Coordination, Personal-Social-Emotional and in the Overall General Development domains. Our results strengthen the call for inclusion of PSAC in routine deworming programs for the control of urinary schistosomiasis and the need to develop locally validated tools to monitor early child development in endemic areas where resources are limited

The association of systemic inflammation and cognitive functions of pre-school aged children residing in a Schistosoma haematobium endemic area in Zimbabwe.

BACKGROUND: Cognitive function is negatively impacted by schistosomiasis and might be caused by systemic inflammation which has been hypothesized to be one of the mechanisms driving cognitive decline, This study explored the association of systemic inflammatory biomarkers; interleukin (IL)-10, IL-6, IL-17, transforming growth factor (TGF-β), tumor necrosis factor (TNF-α), C-reactive protein (CRP) and hematological parameters with cognitive performance of preschool-aged children (PSAC) from an Schistosoma haematobium endemic area. METHODS: The Griffith III tool was used to measure the cognitive performance of 136 PSAC. Whole blood and sera were collected and used to quantify levels of IL-10, TNF-α, IL-6, TGF-β, IL-17 A and CRP using the enzyme-linked immunosorbent assay and hematological parameters using the hematology analyzer. Spearman correlation analysis was used to determine the relationship between each inflammatory biomarker and cognitive performance. Multivariate logistic regression analysis was used to determine whether systemic inflammation due to S. haematobium infection affected cognitive performance in PSAC. RESULTS: Higher levels of TNF-α and IL-6, were correlated with lower performance in the Foundations of Learning domain (r = -0.30; p < 0.001 and r = -0.26; p < 0.001), respectively. Low cognitive performance in the Eye-Hand-Coordination Domain was observed in PSAC with high levels of the following inflammatory biomarkers that showed negative correlations to performance; TNF-α (r = -0.26; p < 0.001), IL-6 (r = -0.29; p < 0.001), IL-10 (r = -0.18; p < 0.04), WBC (r = -0.29; p < 0.001), neutrophils (r = -0.21; p = 0.01) and lymphocytes (r = -0.25; p = 0.003) The General Development Domain correlated with TNF-α (r = -0.28; p < 0.001) and IL-6 (r = -0.30; p < 0.001). TGF-β, L-17A and MXD had no significant correlations to performance in any of the cognitive domains. The overall general development of PSAC was negatively impacted by S. haematobium infections (OR = 7.6; p = 0.008) and (OR = 5.6; p = 0.03) where the PSAC had higher levels of TNF-α and IL-6 respectively. CONCLUSION: Systemic inflammation and S. haematobium infections are negatively associated with cognitive function. We recommend the inclusion of PSAC into mass drug treatment programs

Antibodies elicited during natural infection in a predominantly Plasmodium falciparum transmission area cross-react with sexual stage-specific antigen in P. vivax

© 2017 Elsevier B.V. Infections caused by Plasmodium falciparum and P. vivax account for more than 90% of global malaria burden. Exposure to malaria parasite elicits immune responses during natural infection and it is generally believed that the immunity is not only stage specific but also species specific. However, partial genomic similarity for various antigens in different Plasmodium spp. raises the possibility of immunological cross-reactivity at the level of specific antigens. Serum samples collected from children who were permanent residents of a P. falciparum transmission area in Zimbabwe were screened for antibody reactivity against Pfs48/45, a P. falciparum gametocyte antigen and Pvs48/45, a P. vivax homolog of Pfs48/45 using ELISA. Western blotting was used to further confirm identity of the specific antibody reactivity to the Pfs48/45 and Pvs48/45 proteins. Pan Plasmodium PCR and nested PCR were used to confirm infection with the Plasmodium species. Twenty-seven percent (49/181) of the participants were found to be sero-positive for Pfs48/45 and 73% (n = 36) of these Pfs48/45 positive sera also showed reactivity with Pvs48/45. Immune cross-reactivity revealed by ELISA was also confirmed by Western blot analysis using a panel of randomly selected 23 Pfs48/45 and Pvs48/45 ELISA positive samples. Nested PCR analysis of 27 blood samples randomly selected from the 36 that showed positive ELISA reactivity to both Pfs48/45 and Pvs48/45 antigens confirmed infection with P. falciparum and generalized absence of P. vivax except for a single sample which revealed PCR positivity for both P. vivax and P. falciparum. Our studies with sera samples from a predominantly P. falciparum transmission area in Zimbabwe suggest immunological cross-reactivity with Pvs48/45, thus raising the possibility of partial species cross-reactive immunity and possible cross-boosting of immunity during co-infection with P. falciparum and P. vivax

Prevalence of Plasmodium falciparum transmission reducing immunity among primary school children in a malaria moderate transmission region in Zimbabwe

© 2016 Elsevier B.V. Malaria continues to cause alarming morbidity and mortality in more than 100 countries worldwide. Antigens in the various life cycle stages of malaria parasites are presented to the immune system during natural infection and it is widely recognized that after repeated malaria exposure, adults develop partially protective immunity. Specific antigens of natural immunity represent among the most important targets for the development of malaria vaccines. Immunity against the transmission stages of the malaria parasite represents an important approach to reduce malaria transmission and is believed to become an important tool for gradual elimination of malaria. Development of immunity against Plasmodium falciparum sexual stages was evaluated in primary school children aged 6–16 years in Makoni district of Zimbabwe, an area of low to modest malaria transmission. Malaria infection was screened by microscopy, rapid diagnostic tests and finally using nested PCR. Plasma samples were tested for antibodies against recombinant Pfs48/45 and Pfs47 by ELISA. Corresponding serum samples were used to test for P. falciparum transmission reducing activity in Anopheles stephensi and An. gambiae mosquitoes using the membrane feeding assay. The prevalence of malaria diagnosed by rapid diagnostic test kit (Paracheck)™ was 1.7%. However, of the randomly tested blood samples, 66% were positive by nested PCR. ELISA revealed prevalence (64% positivity at 1:500 dilution, in randomly selected 66 plasma samples) of antibodies against recombinant Pfs48/45 (mean A 405 nm = 0.53, CI = 0.46–0.60) and Pfs47 (mean A405 nm = 0.91, CI = 0.80–1.02); antigens specific to the sexual stages. The mosquito membrane feeding assay demonstrated measurable transmission reducing ability of the samples that were positive for Pfs48/45 antibodies by ELISA. Interestingly, 3 plasma samples revealed enhancement of infectivity of P. falciparum in An. stephensi mosquitoes. These studies revealed the presence of antibodies with transmission reducing immunity in school age children from a moderate transmission area of malaria, and provide further support to exploit target antigens such as Pfs48/45 for further development of a malaria transmission blocking vaccine