Differential T-cell responses of semi-immune and susceptible malaria subjects to in silico predicted and synthetic peptides of Plasmodium falciparum.

Malaria remains a public health hazard in tropical countries as a consequence of the rise and spread of drug and insecticide resistances; hence the need for a vaccine with widespread application. Protective immunity to malaria is known to be mediated by both antibody and cellular immune responses, though characterization of the latter has been less extensive. The aim of the present investigation was to identify novel T-cell epitopes that may contribute to naturally acquired immune responses against malaria. Using the Microsoft software, Epitome™ T-cell peptide epitopes on 19 Plasmodium falciparum proteins in the Plasmodium Database (www.plasmodb.org.PlasmoDB 9.0) were predicted in-silico. The peptides were synthesized and used to stimulate peripheral blood mononuclear cells (PBMCs) in 14 semi-immune and 21 malaria susceptible subjects for interferon-gamma (IFN-γ) production ex-vivo. The level of IFN-γ production, a marker of T-cell responses, was measured by ELISPOT assay in semi-immune subjects (SIS) and frequently sick subjects (FSS) from an endemic zone with perennial malaria transmission. Of the 19 proteins studied, 17 yielded 27 pools (189 peptides), which were reactive with the subjects' PBMCs when tested for IFN-γ production, taking a stimulation index (SI) of ≥2 as a cutoff point for a positive response. There were 10 reactive peptide pools (constituting eight protein loci) with an SI of 10 or greater. Of the 19 proteins studied, two were known vaccine candidates (MSP-8 and SSP2/TRAP), which reacted both with SIS and FSS. Similarly the hypothetical proteins (PFF1030w, PFE0795c, PFD0880w, PFC0065c and PF10_0052) also reacted strongly with both SIS and FSS making them attractive for further characterization as mediators of protective immunity and/or pathogenesis.

Antimicrobial and toxicological activities of five medicinal plant species from Cameroon traditional medicine.

BACKGROUND: Infectious diseases caused by multiresistant microbial strains are on the increase. Fighting these diseases with natural products may be more efficacious. The aim of this study was to investigate the in vitro antimicrobial activity of methanolic, ethylacetate (EtOAc) and hexanic fractions of five Cameroonian medicinal plants (Piptadeniastum africana, Cissus aralioides, Hileria latifolia, Phyllanthus muellerianus and Gladiolus gregasius) against 10 pathogenic microorganisms of the urogenital and gastrointestinal tracts. METHODS: The fractions were screened for their chemical composition and in vivo acute toxicity was carried out on the most active extracts in order to assess their inhibitory selectivity. The agar well-diffusion and the micro dilution methods were used for the determination of the inhibition diameters (ID) and Minimum inhibitory concentrations (MIC) respectively on 8 bacterial species including two Gram positive species (Staphylococcus aureus, Enterococcus faecalis), and six Gram negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Shigella flexneri, Salmonella typhi) and two fungal isolates (Candida albicans, Candida krusei). The chemical composition was done according to Harbone (1976), the acute toxicity evaluation according to WHO protocol and the hepatic as well as serum parameters measured to assess liver and kidney functions. RESULTS: The chemical components of each plant's extract varied according to the solvent used, and they were found to contain alkaloids, flavonoids, polyphenols, triterpens, sterols, tannins, coumarins, glycosides, cardiac glycosides and reducing sugars. The methanolic and ethylacetate extracts of Phyllanthus muellerianus and Piptadeniastum africana presented the highest antimicrobial activities against all tested microorganisms with ID varying from 8 to 26 mm and MIC from 2.5 to 0.31 mg/ml. The in vivo acute toxicity study carried out on the methanolic extracts of Phyllanthus muellerianus and Piptadeniastrum africana indicated that these two plants were not toxic. At the dose of 4 g/kg body weight, kidney and liver function tests indicated that these two medicinal plants induced no adverse effect on these organs. CONCLUSION: These results showed that, all these plant's extracts can be used as antimicrobial phytomedicines which can be therapeutically used against infections caused by multiresistant agents. Phyllanthus muellerianus, Piptadeniastum africana, antimicrobial, acute toxicity, kidney and liver function tests, Cameroon Traditional Medicine.

Low anticoagulant heparin disrupts Plasmodium falciparum rosettes in fresh clinical isolates.

The binding of Plasmodium falciparum parasitized erythrocytes to uninfected erythrocytes (rosetting) is associated with severe malaria. The glycosaminoglycan heparan sulfate is an important receptor for rosetting. The related glycosaminoglycan heparin was previously used in treatment of severe malaria, although abandoned because of the occurrence of severe bleedings. Instead, low anticoagulant heparin (LAH) has been suggested for treatment. LAH has successfully been evaluated in safety studies and found to disrupt rosettes and cytoadherence in vitro and in vivo in animal models, but the effect of LAH on fresh parasite isolates has not been studied. Herein, we report that two different LAHs (DFX232 and Sevuparin) disrupt rosettes in the majority of fresh isolates from Cameroonian children with malaria. The rosette disruption effect was more pronounced in isolates from complicated cases than from mild cases. The data support LAH as adjunct therapy in severe malaria.

Social stigma as an epidemiological determinant for leprosy elimination in Cameroon.

Leprosy has been eliminated as a public health problem in most countries of the world according to the WHO, but the social stigma to the disease is still very high. The present study was performed to investigate the role of social stigma as a determinant for leprosy elimination in a leprosy endemic region of Cameroon. Focus group discussions, in-depth interviews and structured questionnaires were used to investigate leprosy social stigma among lepers, their contacts and a control group consisting of patients attending a health facility for reasons other than leprosy. Informed consent was sought and gained prior to starting the study. Focus group discussions and in-depth interviews identified three types of stigma: lack of self-esteem, tribal stigma and complete rejection by society. From the 480 structured questionnaires administered, there were overall positive attitudes to lepers among the study population and within the divisions (P=0.0). The proportion of participants that felt sympathetic with deformed lepers was 78.1% [95% confidence interval (CI): 74.4-81.8%] from a total of 480. Three hundred and ninety nine (83.1%) respondents indicated that they could share a meal or drink at the same table with a deformed leper (95% CI: 79.7-86.5%). Four hundred and three (83.9%) participants indicated that they could have a handshake and embrace a deformed leper (95% CI: 80.7-87.3%). A total of 85.2% (95.0% CI: 81.9-88.4%) participants affirmed that they could move with a deformed leper to the market or church. A high proportion of 71.5% (95.0% CI: 67.5%-75.5%) participants stated that they could offer a job to a deformed leper. The results indicate that Menchum division had the lowest mean score of 3.3 on positive attitudes to leprosy compared with Mezam (4.1) and Boyo (4.8) divisions. The high proportion of positive attitudes among the participants and in different divisions is a positive indicator that the elimination of leprosy social stigma is progressing in the right direction. Quantification of stigma to assess the elimination struggle is a new research area in public health.

Genital mycoplasmas in women attending the Yaoundé University Teaching Hospital in Cameroon.

Genital mycoplasmas are implicated in pelvic inflammatory diseases, puerperal infection, septic abortions, low birth weight, nongonococcal urethritis and prostatitis as well as spontaneous abortion and infertility in women. There is paucity of data on colonisation of genital mycoplasma in women and their drug sensitivity patterns. The aim of our study was to determine the prevalence of genital mycoplasmas (Ureaplasma urealiticum and Mycoplasma hominis) infection and their drug sensitivity patterns in women. A mycofast kit was used for biochemical determination of mycoplasma infection in 100 randomly selected female patients aged 19-57 years, attending the University of Yaoundé Teaching Hospital (UYTH) from March to June 2010. Informed consent was sought and gained before samples were collected. Genital mycoplasmas were found in 65 patients (65%) [95% CI=55.7-74.3%] and distributed as 41 (41%) [95% CI=31.4-50.6%] for U. urealiticum and 4 (4%) [95% CI=0.20- 7.8%] for M. hominis while there was co-infection in 20 women (20%) [95% CI=12.16-27.84%]. In our study, 57 (57%) [95% CI=47.3-67%] had other organisms, which included C. albicans (19 [19%]), G. vaginalis (35 [35%]) and T. vaginalis (3 [3%]). Among the 65 women with genital mycoplasma, the highest co-infection was with G. vaginalis (33.8%). Pristinamycine was the most effective antibiotic (92%) and sulfamethoxazole the most resistant (8%) antibiotic to genital mycoplasmas. We conclude that genital mycoplasma is a problem in Cameroon and infected women should be treated together with their partners.

Seroprevalence of Toxoplasma gondii infection among pregnant women in Cameroon.

Toxoplasmosis is caused by an intracellular protozoan, Toxoplasma gondii, which has a wide geographical distribution. The congenital form results in a gestational form that can present a temporary parasiteamia that will infect the fetus. For this reason early diagnosis in pregnancy is highly desirable, allowing prompt intervention in cases of infection. The aim of this study was to determine the seroprevalence of Toxoplasma gondii antibodies among pregnant women attending the Douala General Hospital. The study was carried out between March and July 2009, whereby 110 pregnant women were tested for IgG and IgM antibodies and information about eating habits and hygienic conditions was collected using a questionnaire. These women's ages ranged from 20-44 years old with an average of 29.9 years; the overall IgG and IgM seroprevalence was 70% and 2.73 % respectively. Seroprevalence was significantly high amongst women who ate raw vegetables (76.39%, P<0.05) and there was a significant trend towards a higher seroprevalence in women who did not have a good source of water (75.58%, P<0.05). This research showed that consumption of raw vegetables and poor quality drinking water are two risk factors associated with Toxoplasma gondii infection amongst pregnant women attending the Douala General Hospital in Cameroon.

Seroprevalence of Toxoplasma Gondii Infection among Pregnant Women in Cameroon

Toxoplasmosis is caused by an intracellular protozoan; Toxoplasma gondii; which has a wide geographical distribution. The congenital form results in a gestational form that can present a temporary parasiteamia that will infect the fetus. For this reason early diagnosis in pregnancy is highly desirable; allowing prompt intervention in cases of infection. The aim of this study was to determine the seroprevalence of Toxoplasma gondii antibodies among pregnant women attending the Douala General Hospital. The study was carried out between March and July 2009; whereby 110 pregnant women were tested for IgG and IgM antibodies and information about eating habits and hygienic conditions was collected using a questionnaire. These women's ages ranged from 20-44 years old with an average of 29.9 years; the overall IgG and IgM seroprevalence was 70and 2.73respectively. Seroprevalence was significantly high amongst women who ate raw vegetables (76.39; P0.05) and there was a significant trend towards a higher seroprevalence in women who did not have a good source of water (75.58; P0.05). This research showed that consumption raw vegetables and poor quality drinking water are two risk factors associated with Toxoplasma gondii infection amongst pregnant women attending the Douala General Hospital in Cameroon

Genital Mycoplasmas in Women Attending the Yaounde University Teaching Hospital in Cameroon

Genital mycoplasmas are implicated in pelvic inflammatory diseases; puerperal infection; septic abortions; low birth weight; nongonococcal urethritis and prostatitis as well as spontaneous abortion and infertility in women. There is paucity of data on colonisation of genital mycoplasma in women and their drug sensitivity patterns. The aim of our study was to determine the prevalence of genital mycoplasmas (Ureaplasma urealiticum and Mycoplasma hominis) infection and their drug sensitivity patterns in women. A mycofast kit was used for biochemical determination of mycoplasma infection in 100 randomly selected female patients aged 19-57 years; attending the University of Yaounde Teaching Hospital (UYTH) from March to June 2010. Informed consent was sought and gained before samples were collected. Genital mycoplasmas were found in 65 patients (65) [95CI=55.7-74.3] and distributed as 41 (41) [95CI=31.4-50.6] for U. urealiticum and 4 (4) [95CI=0.20-7.8] for M. hominis while there was co-infection in 20 women (20) [95CI=12.16-27.84]. In our study; 57 (57) [95CI=47.3- 67] had other organisms; which included C. albicans (19 [19]); G. vaginalis (35 [35]) and T. vaginalis (3 [3]). Among the 65 women with genital mycoplasma; the highest co-infection was with G. vaginalis (33.8). Pristinamycine was the most effective antibiotic (92) and sulfamethoxazole the most resistant (8) antibiotic to genital mycoplasmas. We concluded that genital mycoplasma is a problem in Cameroon and infected women should be treated together with their partners

Social Stigma as an Epidemiological Determinant for Leprosy Elimination in Cameroon

Leprosy has been eliminated as a public health problem in most countries of the world according to the WHO; but the social stigma to the disease is still very high. The present study was performed to investigate the role of social stigma as a determinant for leprosy elimination in a leprosy endemic region of Cameroon. Focus group discussions; in-depth interviews and structured questionnaires were used to investigate leprosy social stigma among lepers; their contacts and a control group consisting of patients attending a health facility for reasons other than leprosy. Informed consent was sought and gained prior to starting the study. Focus group discussions and in-depth interviews identified three types of stigma: lack of self-esteem; tribal stigma and complete rejection by society. From the 480 structured questionnaires administered; there were overall positive attitudes to lepers among the study population and within the divisions (P=0.0). The proportion of participants that felt sympathetic with deformed lepers was 78.1[95confidence interval (CI): 74.4-81.8] from a total of 480. Three hundred and ninety nine (83.1) respondents indicated that they could share a meal or drink at the same table with a deformed leper (95CI: 79.7-86.5). Four hundred and three (83.9) participants indicated that they could have a handshake and embrace a deformed leper (95CI: 80.7-87.3). A total of 85.2(95.0CI: 81.9-88.4) participants affirmed that they could move with a deformed leper to the market or church. A high proportion of 71.5(95.0CI: 67.5-75.5) participants stated that they could offer a job to a deformed leper. The results indicate that Menchum division had the lowest mean score of 3.3 on positive attitudes to leprosy compared with Mezam (4.1) and Boyo (4.8) divisions. The high proportion of positive attitudes among the participants and in different divisions is a positive indicator that the elimination of leprosy social stigma is progressing in the right direction. Quantification of stigma to assess the elimination struggle is a new research area in public health