Immunoinformatics-Based Designing of Novel and Potent Multi-Epitope PSA D15 and Cag11 Immunogens for Helicobacter pylori Immunodiagnostic Assay Development.

Helicobacter pylori (H. pylori) strain is the most genetically diverse pathogenic bacterium and now alarming serious human health concern ranging from chronic gastritis to gastric cancer and human death all over the world. Currently, the majority of commercially available diagnostic assays for H. pylori is a challenging task due to the heterogeneity of virulence factors in various geographical regions. In this concern, designing of universal multi-epitope immunogenic biomarker targeted for all H. pylori strains would be crucial to successfully immunodiagnosis assay and vaccine development for H. pylori infection. Hence, the present study aimed to explore the potential immunogenic epitopes of PSA D15 and Cag11 proteins of H. pylori, using immunoinformatics web tools in order to design novel immune-reactive multi-epitope antigens for enhanced immunodiagnosis in humans. Through an in silico immunoinformatics approach, high-ranked B-cell, MHC-I, and MHC-II epitopes of PSA D15 and Cag11 proteins were predicted, screened, and selected. Subsequently, a novel multi-epitope PSA D15 and Cag11 antigens were designed by fused the high-ranked B-cell, MHC-I, and MHC-II epitopes and 50S ribosomal protein L7/L12 adjuvant using linkers. The antigenicity, solubility, physicochemical properties, secondary and tertiary structures, 3D model refinement, and validations were carried. Furthermore, the designed multi-epitope antigens were subjected to codon adaptation and in silico cloning, immune response simulation, and molecular docking with receptor molecules. A novel, stable multi-epitope PSA D15 and Cag11 H. pylori antigens were developed and immune simulation of the designed antigens showed desirable levels of immunological response. Molecular docking of designed antigens with immune receptors (B-cell, MHC-I, MHC-II, and TLR-2/4) revealed robust interactions and stable binding affinity to the receptors. The codon optimized and in silico cloned showed that the designed antigens were successfully expressed (CAI value of 0.95 for PSA D15 and 1.0 for Cag11) after inserted into pET-32ba (+) plasmid of the E. coli K12 strain. In conclusion, this study revealed that the designed multi-epitope antigens have a huge immunological potential candidate biomarker and useful in developing immunodiagnostic assays and vaccines for H. pylori infection.

Antimalarial Efficacy and Safety of Senna occidentalis (L.) Link Root Extract in Plasmodium berghei-Infected BALB/c Mice.

Background: Emergence of Plasmodium resistance to antimalarial drugs presents a major drawback in efforts to control malaria. To address this problem, there is an urgent and continuous need for the development of new and effective antimalarial agents. Senna occidentalis (L.) link extract has exhibited in vitro antiplasmodial activity in many pharmacological studies. To our knowledge, data on its in vivo antimalarial efficacy is still very limited. A recent study demonstrated that polar extracts from the plant roots inhibit Plasmodium berghei proliferation in a mouse model. This study further describes the efficacy and safety of a methanolic root extract of the plant as an antimalarial agent by demonstrating its effect on hematological, biochemical, and histological parameters of Plasmodium berghei-infected BALB/c mice. Methods: Rane's test, a curative approach, was used to evaluate the antimalarial efficacy of Senna occidentalis methanolic root extract in Plasmodium berghei-infected BALB/c mice. The effect of the extract on both hematological and biochemical parameters was evaluated using automated analyzers. Kidney, liver, lung, spleen, and brain tissues were harvested from euthanized mice and examined for changes in organ architecture. Results: This study demonstrates that methanolic root extract of Senna occidentalis significantly inhibited Plasmodium berghei parasitemia in BALB/c mice (p < 0.01). Infected mice that were treated with the extract depicted a significantly low level of total leucocytes (p < 0.01), red blood cell distribution width (p < 0.01), and a significantly high hemoglobin concentration (p < 0.001) compared to the infected animals that were administered with the vehicle only. The infected animals that were treated with the extract exhibited a significantly low level of urea, creatinine, bilirubin, and alkaline phosphatase (p < 0.05), compared to the infected animals that were given the vehicle only. The level of sodium, potassium and chloride ions, lymphocytes, granulocytes, hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration, total protein, albumin, aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total platelets, mean platelet volume (MPV), and platelet distribution width of the infected animals treated with the extract was not significantly different from those of the infected animals that were given the vehicle only (p > 0.05). The extract alleviated organ pathological changes in the infected mice. The extract did not induce any remarkable adverse effect on the growth, hematological, and biochemical parameters of uninfected animals (p > 0.05). In addition, administration of the extract did not alter the gross appearance and histological architecture of the organs, implying that the extract was well tolerated in mice. Conclusions: Senna occidentalis methanolic root extract exhibited good antimalarial activity against Plasmodium berghei and may be safe in mice.

Phytochemical Profile and Antimicrobial Activities of Edible Mushroom Termitomyces striatus.

The mushroom Termitomyces striatus is an edible mushroom that grows wildly and belongs to the family Lyophyllaceae. Studies in the last few decades have demonstrated that mushrooms and their active components have beneficial effects on a variety of biological systems. Some mushrooms do exhibit antibacterial properties. Qualitative phytochemical profile was done on the mushroom Termitomyces striatus to establish the presence of compounds responsible for important biological activities. This study also investigated the effect of Termitomyces striatus extracts on certain bacterial strains that included Escherichia coli and Pseudomonas aeruginosa representing the Gram-negative bacteria and Bacillus subtilis and Staphylococcus aureus representing Gram-positive bacteria. The fungi were represented by Candida albicans and Saccharomyces cerevisiae. The mushroom was collected in western Kenya, air-dried, and crushed into powder, followed by extraction using water, methanol, and dichloromethane (DCM) solvents. Antibacterial and antifungal activities were evaluated using the disc-diffusion method. Qualitative phytochemical screening of the aqueous extract revealed the presence of alkaloids, flavonoids, steroids, sterols, saponins, phenols, carbohydrates, and proteins. The three extracts exhibited antibacterial against tested bacterial strains. The DCM extract revealed higher effects among the bacterial strains tested. The three extracts showed antifungal effects against C. albicans. However, both methanol and aqueous extracts did not inhibit growth of S. cerevisiae. In conclusion, T. striatus extracts are a promising source of novel antimicrobial and antifungal agents.

Serological Evidence of Chikungunya Virus Infection Among Suspected Measles Cases in Selected Regions of Kenya: 2008-2014.

Chikungunya virus (family Togavirdae and genus Alphavirus) is an emerging and reemerging virus of public health importance both regionally and globally. In Kenya, about 50-60% of the suspected measles cases remain undiagnosed once measles and rubella is ruled out by immunoglobulin M (IgM) ELISA thus prompted the need to do differential diagnosis on the measles/rubella negative samples. Nothing is known about the role played by chikungunya infection among these suspected measles cases. Febrile rash illness is a common clinical presentation of arboviruses, including chikungunya. In this study, we conducted a serosurvey to explore the possible role of chikungunya infections among suspected measles cases in Kenya that had tested negative for measles and rubella. Sera were tested by commercially available ELISA for the presence of IgG and IgM antibodies against the chikungunya virus. All positive samples for chikungunya by ELISA were confirmed by plaque reduction neutralization test (PRNT), and to rule out cross-reactivity with other alphaviruses a panel of viruses was used, namely o' nyong' nyong, Semliki Forest, and Sindbis viruses. Of the 392 serum samples screened, 0.3% (n = 1) tested positive for IgM antibodies, while 4.6% (n = 18) tested positive for IgG antibodies against the chikungunya virus. PRNT results indicated 2 (11%) chikungunya positives and 7 (38.9%) o' nyong' nyong positives. We recommend awareness among health care providers and improved surveillance for these arboviruses by both serology and molecular testing. Testing for other pathogens should also be done to improve disease detection and diagnosis.

An investigation into the role of chronic Schistosoma mansoni infection on Human Papillomavirus (HPV) vaccine induced protective responses.

BACKGROUND: Schistosoma mansoni is one of the most common helminth infections affecting a large population of people in sub-Saharan Africa. This helminth infection is known to cause immunomodulation which has affected the efficacy of a number of vaccines. This study examined whether a chronic schistosoma infection has an effect on the immunogenicity of HPV vaccine which is currently administered to girls and women aged 9 to 24. Little is known about the immune responses of the HPV vaccine in individuals with chronic schistosomiasis. METHODS: This study was carried out at the Institute of Primate Research (IPR) and involved an Olive baboon model. The experimental animals were randomly placed into three groups (n = 3-4); Two groups were infected with S. mansoni cercaria, and allowed to reach chronic stage (week 12 onwards), at week 13 and 14 post-infection, one group was treated with 80mg/kg of praziquantel (PZQ). Sixty four weeks post schistosoma infection, all groups received 2 doses of the Cervarix HPV vaccine a month apart. Specific immune responses to the HPV and parasite specific antigens were evaluated. RESULTS: Animals with chronic S. mansoni infection elicited significantly reduced levels of HPV specific IgG antibodies 8 weeks after vaccination compared the PZQ treated and uninfected groups. There was no significant difference in cellular proliferation nor IL-4 and IFN-γ production in all groups. CONCLUSION: Chronic S. mansoni infection results in reduction of protective HPV specific IgG antibodies in a Nonhuman Primate model, suggesting a compromised effect of the vaccine. Treatment of schistosomiasis infection with PZQ prior to HPV vaccination, however, reversed this effect supporting anti-helminthic treatment before vaccination.

Knowledge and perceptions on childhood asthma among care-takers of children with asthma at a National Referral Hospital in Western Kenya: a descriptive study.

BACKGROUND: Identifying knowledge gaps in asthma self-management and identifying existing myths is an important step in determining appropriate health education and demystifying the myths so as to enhance asthma control. OBJECTIVE: To identify existing knowledge gaps and perceptions among the caregivers of asthmatic children. METHODS: A cross sectional study was done among caretakers of asthmatic children aged 6-11 years at Moi Teaching and Referral Hospital. Data on knowledge and perceptions among caretakers was collected using a questionnaire. RESULTS: A total of 116 caretakers were recruited of whom 71.6% were mothers. Although 60% of the caretakers had asthma medications at home, only a third felt their children were asthmatic. Eighty four (72.4%) had basic asthma knowledge. Syrups were preferred to inhalers by 70.7%, with 64.7% believing that inhalers were for the very sick. Only 36 (31%) felt preventer medications in asthma were necessary. Acceptance of asthma as a diagnosis and presence of asthma drugs were significantly associated with better knowledge of asthma, p-values 0.015 and 0.009 respectively. CONCLUSION: Most caregivers perceive syrups to be better despite having good basic knowledge on asthma. There is need to address asthma perceptions among caretakers in resource poor settings which is likely to improve control.

Anticoccidial effects of Aloe secundiflora leaf extract against Eimeria tenella in broiler chicken.

Anticoccidial effects of Aloe secundiflora crude leaf extract was tested in broiler chickens following oral infection with Eimeria tenella. Sixty 22-day-old birds were divided into six groups of ten birds each. Three treatment groups A, B, and C were fed with the extract (100, 250, and 500 mg/day, respectively) mixed in feed for 10 days, and three control groups: group D (drug control) administered 300 mg/l of sulfachloropyrazine sodium soluble powder in drinking water for 5 days, group E (infected/non-medicated positive control), and group F (uninfected/non-medicated negative control). Except for group F, all groups were orally inoculated with 75,000 sporulated oocysts of E. tenella. The effects of the extract on E. tenella infection were evaluated by severity of bloody diarrhea, body weight (BW) gain, oocyst output, and lesion score. No bird in the treated groups died of coccidiosis, and severity of bloody diarrhea was milder than in the positive control group. BW gains in the treated groups were significantly higher than in group E (p < 0.05). The lesion scores of the treated groups were significantly lower than that of group E. Oocyst output in groups A, B, and C were 11.23, 8.24, and 6.82 × 106, respectively. As compared with the negative control group (12.84 × 106), the reductions in oocyst production were 12.54, 35.83, and 46.88%, respectively. Oocyst output significantly reduced with an increase in Aloe dosage. The findings of this study suggest that Aloe secundiflora extract presents an alternative anticoccidial agent for the control of avian coccidiosis.

Schistosoma mansoni among pre-school children in Musozi village, Ukerewe Island, North-Western-Tanzania: prevalence and associated risk factors.

BACKGROUND: Recent evidence indicates that pre-school children (PSC) living in S. mansoni highly endemic areas are at similar risk of schistosomiasis infection and morbidity as their school aged siblings. Recognizing this fact, the World Health Organization (WHO) is considering including this age group in highly endemic areas in control programmes using mass drug administration (MDA). However, detailed epidemiological information on S. mansoni infection among PSC is lacking for many endemic areas, specifically in Tanzania. This study was conducted to determine the prevalence of S. mansoni infection and its associated risk factors among PSC in Ukerewe Island, North-Western Tanzania. METHODS: This was a cross-sectional study, which studied 400 PSC aged 1-6 years. The Kato-Katz (K-K) technique and the point of care circulating cathodic antigen (CCA) immunodiagnostic test were used to diagnose S. mansoni infection in stool and urine samples respectively. A pre-tested questionnaire was used to collect demographic data and water contact behaviour of the children from their parents/guardians. RESULTS: Based on the K-K technique, 44.4% (95% CI: 39.4-49.4) pre-school children were infected with S. mansoni and the overall geometric mean eggs per gram of faeces (GM-epg) was 110.6 epg with 38.2 and 14.7% having moderate and heavy intensity infections respectively. Based on the CCA, 80.1%, (95% CI: 76.0-84.0) were infected if a trace was considered positive, and 45.9%, (95% CI: 40.9-50.9), were infected if a trace was considered negative. Reported history of lake visits (AOR = 2.31, 95% CI: 1.06-5.01, P < 0.03) and the proximity to the lake shore (<500 m) (AOR = 2.09, 95% CI: 1.05-4.14, P < 0.03) were significantly associated with S. mansoni infection. Reported lake visit frequency (4-7 days/week) was associated with heavy intensities of S. mansoni infection (P < 0.00). CONCLUSION: The prevalence of S. mansoni infection in the study population using K-K and CCA-trace-negative was moderate. The frequency of lake visits and the proximity to the lake shore were associated with the infection of S. mansoni and its intensity. These findings call for the need to include the PSC in MDA programmes, public health education and provision of safe water for bathing.

Epidemiology and interactions of Human Immunodeficiency Virus - 1 and Schistosoma mansoni in sub-Saharan Africa.

Human Immunodeficiency Virus-1/AIDS and Schistosoma mansoni are widespread in sub-Saharan Africa and co-infection occurs commonly. Since the early 1990s, it has been suggested that the two infections may interact and potentiate the effects of each other within co-infected human hosts. Indeed, S. mansoni infection has been suggested to be a risk factor for HIV transmission and progression in Africa. If so, it would follow that mass deworming could have beneficial effects on HIV-1 transmission dynamics. The epidemiology of HIV in African countries is changing, shifting from urban to rural areas where the prevalence of Schistosoma mansoni is high and public health services are deficient. On the other side, the consequent pathogenesis of HIV-1/S. mansoni co-infection remains unknown. Here we give an account of the epidemiology of HIV-1 and S. mansoni, discuss co-infection and possible biological causal relationships between the two infections, and the potential impact of praziquantel treatment on HIV-1 viral loads, CD4+ counts and CD4+/CD8+ ratio. Our review of the available literature indicates that there is evidence to support the hypothesis that S. mansoni infections can influence the replication of the HIV-1, cell-to-cell transmission, as well as increase HIV progression as measured by reduced CD4+ T lymphocytes counts. If so, then deworming of HIV positive individuals living in endemic areas may impact on HIV-1 viral loads and CD4+ T lymphocyte counts.

Epilepsy and tropical parasitic infections in Sub-Saharan Africa: A review.

Several reports have suggested that the high prevalence of epilepsy in sub-Saharan Africa is associated with the high prevalence of parasitic infections affecting the central nervous system. Though epidemiological evidence suggests an association between parasitic infections and epilepsy, the biological causal relationship has not been fully demonstrated for many of these infections. The objective of this paper is to review the available epidemiological evidence on the links between parasitic infections and epilepsy, the pathogenesis and the current gap of knowledge indicating the areas requiring further research. Data for this review were identified and collected using manual and electronic search strategies of published and unpublished sources. In Sub-Saharan Africa, the epidemiology of epilepsy remains unclear and given the differing study designs, the results of available epidemiological studies are difficult to interpret and compare. Evidence from surveys reported a median prevalence of 1.5%. Co-infection of parasitic infections and epilepsy in sub-Saharan Africa are common, particularly in areas characterized by poor hygiene standards. There is an epidemiological link on the association between epilepsy and various parasitic infections. However, the biological causal relationship requires further investigation in adequately designed studies. In conclusion, although several epidemiological and case control studies indicate a relationship between parasitic agents and epilepsy in sub-Saharan Africa, there is a considerable gap of knowledge on the cause and magnitude of the association. Thus, there is an urgent need for systematic epidemiological studies to understand the burden of epilepsy in areas endemic due to preventable parasitic infections, to prove a causal relationship, and to understand the impact of controlling these parasitic diseases on reduction of the burden of epilepsy.

Cellular responses against Schistosoma mansoni in immunized Balb/c mice with soluble proteins from intermediate host, Biomphalaria pfeifferi.

Scores of millions of people around the world are infected by Schistosoma mansoni causing considerable morbidity, mortality and loss of productivity. Safe chemotherapeutic agents have been used though there are challenges of re-infection due to resistance. Both epidemiological and experimental data suggest that acquired cell mediated immunity play significant roles in regulating the intensity of S. mansoni infection as well as its patho-physiologic sequelae. Improved control of this trematode parasite may be obtained with immunization to enhance the resistance of individuals to risk of infection. This study investigated the cellular responses of mice immunized with soluble proteins from foot and digestive gland of the vector snail and challenged with S. mansoni. The proteins were used to immunize the experimental groups then challenged with the S. mansoni. The experimental groups were FT (immunized with foot protein) and DG (immunized with digestive gland). The parameters, which were analyzed to demonstrate protection, included; the worm counts and cellular (IFN-γ, IL-5 cytokines) responses. It was observed that, the experimental groups showed significant protection in terms of worm reduction and immune responses. The group vaccinated with foot protein showed higher protection (87.5%) as compared to the group vaccinated with the digestive gland (50%) in terms of worm reduction. Cytokines (IFN-γ and IL-5) production was present in different levels during the assay time points which showed an aspect of protection. The Foot protein of the vector showed more immunizing power than the digestive gland. Research towards utilizing the two proteins as feasible vaccine candidates is encouraged.

Severe tungiasis in Western Tanzania: case series.

Tungiasis is caused by infestation with the sand flea (Tunga penetrans). This ectoparasitosis is endemic in economically depressed communities in South American and African countries. However, data on the epidemiology of tungiasis in Tanzania are very limited and the disease does not receive much attention from health care professionals. During a community cross sectional survey in northwest Tanzania, we identified five individuals extremely infested with high number of parasites. A total of 435 lesions were recorded with patients presenting with >75 lesions and showed signs of intense acute and chronic inflammation. Superinfection of the lesions characterized by pustule formation, suppuration and ulceration were common. Loss of nails and walking difficulty was also observed. In Tanzanian communities living under extreme poverty characterized by poor housing condition and inadequate health services, tungiasis may cause severe morbidities. Further studies on risk factors and disease-related behavior of affected populations are needed to design adequate control measures.

Mouse cytokine profile skewed towards Th2 in pregnancy during infection with Brucella abortus S19 strain.

The two classes of cytokines Th1 and Th2 determine the type of immune response elicited. The Th2 immune response is associated with successful pregnancy. Brucellosis is an intracellular bacterium that elicits the Th1 response and is known to cause spontaneous abortion in mammalian species. This study sought to determine if Brucella infection causes spontaneous abortion by causing the circulating cytokine profile be Th1 dominant during pregnancy. Forty-eight Swiss white mice were used in this murine model and the S19 strain of Brucella abortus was used in as the infective agent. Pregnant mice in the test group were injected intraperitoneally with 10(5-8) CFU of Brucella and cytokine profile evaluated over the three trimesters of pregnancy. Pregnant mice in the control group were left to go through normal pregnancy and their cytokine profile evaluated over the three trimesters of pregnancy. Cytokines in serum samples were analyzed by Cytometric Bead Array. The data was analyzed using the Paired T- test and p < 0.05 was considered significant. IFN-γ and TNF-α represented the Th1 cytokines while IL-4 and IL-5 represented the Th2 cytokines. None of the mice in the test group had spontaneous abortion. IFN-γ and TNF-α had no significant differences between cytokine levels for infected and uninfected groups in all 3 trimesters of pregnancy. IL-4 levels had significant differences in all three trimesters of pregnancy (t = 13, P = 0.036, 0.0071 and 0.0277). IL-5 levels had significant differences second trimester (t = 14, P = 0.0075). The cytokine profile was robustly Th2. In conclusion, Brucella abortus cannot cause spontaneous abortion by altering the mouse cytokine profile towards Th1 in pregnancy. Elevated IL-4 levels with corresponding suppression of IFN-γ can be used as a marker for successful pregnancy in Brucellosis.

Co-infections with Plasmodium falciparum, Schistosoma mansoni and intestinal helminths among schoolchildren in endemic areas of northwestern Tanzania.

BACKGROUND: Malaria, schistosomiasis and intestinal helminth infections are causes of high morbidity in most tropical parts of the world. Even though these infections often co-exist, most studies focus on individual diseases. In the present study, we investigated the prevalence of Plasmodium falciparum-malaria, intestinal schistosomiasis, soil-transmitted helminth infections, and the respective co-infections, among schoolchildren in northwest Tanzania. METHODS: A cross sectional study was conducted among schoolchildren living in villages located close to the shores of Lake Victoria. The Kato Katz technique was employed to screen faecal samples for S. mansoni and soil-transmitted helminth eggs. Giemsa stained thick and thin blood smears were analysed for the presence of malaria parasites. RESULTS: Of the 400 children included in the study, 218 (54.5%) were infected with a single parasite species, 116 (29%) with two or more species, and 66 (16.5%) had no infection. The prevalences of P. falciparum and S. mansoni were 13.5% (95% CI, 10.2-16.8), and 64.3% (95% CI, 59.6-68.9) respectively. Prevalence of hookworm infection was 38% (95% CI, 33.2-42.8). A. lumbricoides and T. trichiura were not detected. Of the children 26.5% (95% CI, 21.9-30.6) that harbored two parasite species, combination of S. mansoni and hookworm co-infections was the most common (69%). Prevalence of S. mansoni - P. falciparum co-infections was 22.6% (95%CI, 15.3-31.3) and that of hookworm - P. falciparum co-infections 5.7% (95%CI, 2.6-12.8). Prevalence of co-infection of P. falciparum, S. mansoni and hookworm was 2.8% (95%CI, 1.15-4.4). CONCLUSION: Multiple parasitic infections are common among schoolchildren in rural northwest Tanzania. These findings can be used for the design and implementation of sound intervention strategies to mitigate morbidity and co-morbidity.

Association of intestinal helminths and P. falciparum infections in co-infected school children in northwest Tanzania.

Plasmodium falciparum malaria and intestinal helminth infections are among the most common infections in the tropics and they share the same spatial distribution. The objective of this study was to explore the association between infections with intestinal helminths and P. falciparum infection as single helminth infections or co-infections among school children. A cross-sectional study was conducted among 400 school children in Nyamtongo, Sengerema District in Tanzania. The study involved examination of single stool and finger prick blood samples for intestinal helminths and malaria parasites. A Kato-Katz technique was employed to screen for intestinal helminths and Giemsa stained thin and thick blood smears were used to screen for malaria parasites. The results of logistic regression model adjusted for age and sex indicated no association between P. falciparum and S. mansoni (OR= 0.749, 95%CI 0.418-1.344), P. falciparum and hookworm (OR= 0.885, 95%CI 0.489-1.605) and P. falciparum and co-infection of S. mansoni and hookworm (OR=0.859, 95%CI 0.422-1.745). Using multinomial regression model adjusted for age and sex, no association was observed between P. falciparum with Schistosoma mansoni [Ratio of Relative Risk (RRR) = 0.651, 95% Confidence Interval (CI) 0.331-1.363] and hookworm (RRR=0712, CI 0.280-1.765). Similarly, no association was observed between co-infections of S. mansoni + hookworm (RRR=0.635, CI 0.268-1.504) with P. falciparum infection. Coinfections of S. mansoni, hookworm and P. falciparum among school children is common in the Nyamatongo ward, Sengerema District. We recommend prospective longitudinal studies to elucidate the interactions of malaria and helminths and its health impact in risk groups.