Immune response to hepatitis B vaccine following complete immunization of children attending two regional hospitals in the Southwest region of Cameroon: a cross sectional study.

BACKGROUND: Hepatitis B virus (HBV) infection despite being a vaccine preventable disease remains a global public health problem. In Cameroon, the hepatitis B vaccine was introduced in the expanded program on immunisation in 2005, but there has been limited evaluation of the HBV surface antibody response post vaccination. OBJECTIVE: We investigated the immune response to hepatitis B vaccine in infants who received the DPT-Hep B-Hib vaccine, and we assessed HBsAg carriage in non-responders. We also investigated factors associated with non-response or poor response. METHODS: Using a hospital based cross sectional design and a structured questionnaire over a four-month period (January to April 2019), we collected data to determine factors associated with hepatitis B surface antibody (anti-HBs) response from infants aged 6 to 9 months attending infant welfare clinics (IWC) at the Buea and Limbe regional hospitals. We collected venous blood and measured anti-HBs titres using a quantitative Foresight® ELISA. We entered and analysed data using EpiData version 3.1 and SPSS version 25 respectively. RESULTS: Of the 161 infants enrolled, 159 (98.8%) developed anti-HBs antibodies. Of these 159, 157 (97.5%) and 117 (72.7%) developed ≥ 10.0 mIU/ml (seroprotection) and ≥ 100.0 mIU/ml anti-HBs titres respectively. Being younger (6 months old) was associated with seroprotection (Cramer V = 0.322, p = 0.001). Spearman rho's relational analysis showed that immunity against HBV reduced as the duration since the last dose increased (r = -0.172; P = 0.029). However, a Firth logistic regression showed no significant association of factors with inadequate immunity. All 12 (7.5%) infants exposed to HBV at birth, received the hepatitis B vaccine at birth, including four who received HBIG, and all were protected. Four infants (2.5%) had anti-HBs titres < 10.0 mIU/mL (non-responders) but had no peculiarity. CONCLUSION: The seroprotective rate following hepatitis B vaccination of infants is high even in exposed infants. Our study suggests that Cameroon's HBV vaccine in the Expanded Program on Immunisation (EPI) is effective against HBV, although we could not account for the 2.5% non-response rate. Large scale studies are needed to further explore non-response to the vaccine.

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.

Anthraquinones from the stem bark of Stereospermum zenkeri with antimicrobial activity.

Two anthraquinones, zenkequinones A and B were isolated from the stem bark of Stereospermum zenkeri together with known sterequinone-F, p-coumaric acid, sitosterol-3-O-beta-D-glucopyranoside and 3beta-hydroxyolean-12-en-28-O-beta-D-glucopyranoside. Their structures were established by spectroscopic methods. The antimicrobial activity of the isolated compounds was evaluated against six multiresistant strains of pathogens. Zenkequinone B showed the best antibacterial activity (MIC 9.50 microg/ml) against gram-negative Pseudomonas aeruginosa.

In vitro Antifungal Susceptibility Patterns of Candida Albicans from HIV and AIDS Patients Attending the Nylon Health District Hospital in Douala, Cameroon.

HIV and AIDS are major public health problems in Cameroon where the HIV prevalence is 5.5%. Candidiasis is the leading opportunistic mycosis in HIV and AIDS patients. The objective of this study was to determine the in vitro antifungal susceptibility pattern of Candida albicans in HIV and AIDS patients to eight antifungal agents in the Nylon Health District of Douala in Cameroon. Three hundred and four HIV and AIDS patients were recruited between March and August 2007 to participate in a cross-sectional study. All subjects who fulfilled the inclusion criteria were enrolled. Informed consent was obtained from all subjects before samples were collected. Three samples comprising oral swabs, vagina/urethra swabs and a mid-stream urine were collected from each subject. Specimens were cultured on sabouraud dextrose agar and C. albicans isolates were identified using the germ tube technique. The disk diffusion method was used for antifungal susceptibility testing using eight antifungal agents. The prevalence of candidiasis in the study population was 67.8% (95% CI: 62.5-73.1%) and that of C. albicans was 42.8% (95% CI: 37.2-48.4%). Oral swabs had the highest prevalence of C. albicans followed by vaginal/urethral samples (52.6% vs. 29.7% respectively). Forty (30.8%) subjects had C. albicans infection at more than one collection site. There was a statistically significant difference in the infectivity of C. albicans with age, sex and site of infection (P<0.05). C. albicans isolates were most sensitive to ketoconazole (80%) followed by econazole (64.6%) while fluconazole and 5-flurocytosin recorded the poorest sensitivities (22.9% vs 24.6%, respectively). There was a statistically significant difference in the sensitivity pattern of antifungal agents with respect to the site of isolation of the organism (P<0.05). Ketoconazole is the drug of choice for the treatment of C. albicans infection in HIV and AIDS patients in the Nylon Health District of Douala, 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 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.

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.

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.