Hepatitis E Virus in Water Environments: A Systematic Review and Meta-analysis.

Hepatitis E virus (HEV) is responsible for acute hepatitis in humans, through foodborne, zoonotic, and waterborne transmission routes. This study aimed to assess the prevalence of HEV in water matrices. Six categories were defined: untreated and treated wastewater, surface water (river, lake, and seawater), drinking water, groundwater, and other water environments (irrigation water, grey water, reservoir water, flood water, and effluent of pig slaughterhouse). We searched PubMed, Web of Science, Global Index Medicus, and Excerpta Medica Database. Study selection and data extraction were performed by at least two independent investigators. Heterogeneity (I2) was assessed using the χ2 test on the Cochran Q statistic and H parameter. Sources of heterogeneity were explored by subgroup analysis. This study is registered with PROSPERO, number CRD42021289116. We included 87 prevalence studies from 58 papers, 66.4% of which performed in Europe. The overall prevalence of HEV in water was 9.8% (95% CI 6.4-13.7). The prevalence was higher in untreated wastewater (15.1%) and lower in treated wastewater (3.8%) and in drinking water (4.7%). In surface water, prevalence was 7.4%, and in groundwater, the percentage of positive samples, from only one study available, was 8.3%. Overall, only 36.8% of the studies reported the genotype of HEV, with genotype 3 (HEV-3) prevalent (168 samples), followed by HEV-1 (148 sample), and HEV-4 (2 samples). High-income countries were the most represented with 59/87 studies (67.8%), while only 3/87 (3.5%) of the studies were performed in low-income countries. The overall prevalence obtained of this study was generally higher in industrialized countries. Risk of bias was low in 14.9% of the studies and moderate in 85.1%. The results of this review showed the occurrence of HEV in different waters environments also in industrialized countries with sanitation and safe water supplies. While HEV transmission to humans through water has been widely demonstrated in developing countries, it is an issue still pending in industrialized countries. Better knowledge on the source of pollution, occurrence, survival in water, and removal by water treatment is needed to unravel this transmission path.

Assessing the performance of a Fasciola gigantica serum antibody ELISA to estimate prevalence in cattle in Cameroon.

BACKGROUND: Cattle rearing in Cameroon is both economically and culturally important, however parasitic diseases detrimentally impact cattle productivity. In sub-Saharan Africa bovine fasciolosis is generally attributed to F. gigantica, although understanding of Fasciola species present and local epidemiology in individual countries is patchy. Partly limited by the lack of representative surveys and understanding of diagnostic test perfromance in local cattle populations. The aims of this paper were to determine the Fasciola species infecting cattle, develop a species specific serum antibody ELISA, assess the performance of the ELISA and use it to assess the prevalence of F. gigantica exposure in two important cattle-rearing areas of Cameroon. RESULTS: A random sample of Fasciola parasites were collected and were all identified as F. gigantica (100%, CI:94.0-100%, n = 60) using RAPD-PCR analysis. A F. gigantica antibody ELISA was developed and initially a diagnostic cut-off was determined using a sample of known positive and negative cattle. The initial cut-off was used as starting point to estimate an optimal cut-off to estimate the best combination of sensitivity and specificity. This was achieved through sampling a naturally infected population with known infection status (cattle slaughtered at Bamenda abattoir, North West Region (n = 1112) and Ngaoundere abattoir, Vina Division, Adamawa Region (n = 776) in Cameroon). These cattle were tested and results analysed using a Bayesian non-gold standard method. The optimal cut-off was 23.5, which gave a sensitivity of 65.3% and a specificity of 65.2%. The prevalence of exposure to F. gigantica was higher in cattle in Ngaoundere (56.4% CI: 50.2-60.0%) than Bamenda (0.6% CI: 0.0-1.4%). CONCLUSION: Fasciola gigantica was identified as the predominant Fasciola species in Cameroon. Although the sensitivity and specificity F. gigantica antibody ELISA requires improvement, the test has shown to be a potentially useful tool in epidemiological studies. Highlighting the need for better understanding of the impact of F. gigantica infections on cattle production in Cameroon to improve cattle production in the pastoral systems of Central-West Africa. This paper also highlights that non-gold standard latent class methods are useful for assessing diagnostic test performance in naturally-infected animal populations in resource limited settings.

Molecular epidemiology of Mycobacterium bovis in Cameroon.

We describe the largest molecular epidemiological study of Bovine Tuberculosis (bTB) in a sub-Saharan African country with higher spatial resolution providing new insights into bTB. Four hundred and ninety-nine samples were collected for culture from 201 and 179 cattle with and without bTB-like lesions respectively out of 2,346 cattle slaughtered at Bamenda, Ngaoundere, Garoua and Maroua abattoirs between 2012-2013. Two hundred and fifty-five M. bovis were isolated, identified and genotyped using deletion analysis, Hain® Genotype MTBC, spoligotyping and MIRU-VNTR. African 1 was the dominant M. bovis clonal complex, with 97 unique genotypes including 19 novel spoligotypes representing the highest M. bovis genetic diversity observed in Africa to date. SB0944 and SB0953 dominated (63%) the observed spoligotypes. A third of animals with multiple lesions had multiple strain infections. Higher diversity but little evidence of recent transmission of M. bovis was more common in Adamawa compared to the North-West Region. The Adamawa was characterised by a high frequency of singletons possibly due to constant additions from an active livestock movement network compared to the North-West Region where a local expansion was more evident. The latter combined with population-based inferences suggest an unstable and stable bTB-endemic status in the North-West and Adamawa Regions respectively.

Abattoir-based estimates of mycobacterial infections in Cameroon.

Mycobacteria cause major diseases including human tuberculosis, bovine tuberculosis and Johne's disease. In livestock, the dominant species is M. bovis causing bovine tuberculosis (bTB), a disease of global zoonotic importance. In this study, we estimated the prevalence of Mycobacteria in slaughter cattle in Cameroon. A total of 2,346 cattle were examined in a cross-sectional study at four abattoirs in Cameroon. Up to three lesions per animal were collected for further study and a retropharyngeal lymph node was collected from a random sample of non-lesioned animals. Samples were cultured on Lowenstein Jensen media and the BACTEC MGIT 960 system, and identified using the Hain® Genotype kits. A total of 207/2,346 cattle were identified with bTB-like lesions, representing 4.0% (45/1,129), 11.3% (106/935), 23.8% (38/160) and 14.8% (18/122) of the cattle in the Bamenda, Ngaoundere, Garoua and Maroua abattoirs respectively. The minimum estimated prevalence of M. bovis was 2.8% (1.9-3.9), 7.7% (6.1-9.6), 21.3% (15.2-28.4) and 13.1% (7.7-20.4) in the four abattoirs respectively. One M. tuberculosis and three M. bovis strains were recovered from non-lesioned animals. The high prevalence of M. bovis is of public health concern and limits the potential control options in this setting without a viable vaccine as an alternative.

Characterisation of the genes encoding resistance to metronidazole (rdxA and frxA) and clarithromycin (the 23S-rRNA genes) in South African isolates of Helicobacter pylori.

Helicobacter pylori has been incriminated in human diseases, such as peptic ulcer, gastritis and gastric malignancy. Although modern triple-drug regimens are usually highly effective in the treatment of H. pylori infection, the emergence of resistance to two of the most used antibiotics, metronidazole (Mtz) and clarithromycin (Cla), is a serious and increasing problem. Truncations in the rdxA and frxA genes of H. pylori are thought to be associated with Mtz resistance whereas mutations in the pathogen's 23S-ribosomal-RNA (23S-rRNA) genes are associated with Cla resistance. In a recent study, PCR and sequence analysis of the rdxA, frxA and 23S-rRNA genes were used to explore the genetic basis of resistance to Mtz and Cla in H. pylori. When 200 isolates of H. pylori from the Eastern Cape province of South Africa were tested for antibiotic susceptibility, almost all (95·5%) were found resistant to Mtz and 20·0% were found resistant to Cla. Only the Mtz-resistant isolates showed rdxA and frxA truncation. Two point mutations were detected in the 23S-rRNA genes of the Cla-resistant isolates. Many significant changes (resulting in 13 amino-acid substitutions in nine loci and truncated proteins in 14 loci) were observed in the rdxA genes of the Mtz-resistant isolates, and it appears that, compared with the rarer changes detected in frxA, such mutations may contribute more significantly to the high prevalence of Mtz resistance. To guide empiric treatment, the genotypes and antibiotic susceptibility of H. pylori in the Eastern Cape province of South Africa need to be monitored regularly.

Helicobacter pylori prevalence in dyspeptic patients in the Eastern Cape province - race and disease status.

Objectives. We examined Helicobacter pylori infection in patients with gastric-related morbidities at Livingstone Hospital, Port Elizabeth, to determine the prevalence and risk factors for infection according to race, endoscopic diagnosis, age and sex. Methods. Gastric biopsies were collected from 254 consecutive patients and H. pylori isolated on Columbia agar base supplemented with 7% sheep's blood and Skirrow's supplement containing trimethoprim (2.5 mg), vancomycin (5 mg) and cefsulodin (2.5 mg). Amphotericin (2.5 mg) was added to the medium. Recovered isolates were identified following standard microbiology and biochemical techniques. Presumptive isolates were further confirmed by polymerase chain reaction (PCR) targeting the glmM gene. Fisher's exact test was used to assess the univariate association between H. pylori infection and the possible risk factors. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated to measure the strength of association, using EPI INFO 3.41 software. P-values <0.05 were required for significance. Results. The overall prevalence of H. pylori was 66.1% (168/254). Of the 168 positive subjects, H. pylori prevalence was highest in patients with non-ulcer dyspepsia (NUD) (32.7%; 55/168), and lowest (0%; 0/168) in those with atypical oesophageal reflux disease and gastroduodenitis, respectively. The prevalence of infection was highest among coloureds (68.4%; 89/130) and lowest in whites (59.5%; 25/ 42). Prevalence increased with age. Conclusion. The prevalence of H. pylori is high in dyspeptic patients in Eastern Cape Province. Gender, antibiotic treatment and alcohol consumption may be risk factors for infection. These findings are of clinical and epidemiological significance.

Molecular and clinical evidence of Ehrlichia chaffeensis infection in Cameroonian patients with undifferentiated febrile illness.

In the U.S.A., human monocytotropic ehrlichiosis (HME) caused by Ehrlichia chaffeensis is an emerging tick-transmitted zoonosis. In Cameroon, where E. canis, E. chaffeensis and E. ewingii have recently been detected in dogs and/or ticks (Rhipicephalus sanguineus), the potential exists for human infections. Patients from the coastal region of Cameroon who had acute fevers of unknown aetiology were therefore checked for ehrlichial infection, using a real-time PCR that amplifies part of a genus-specific gene (dsb) that codes for a disulphide-bond formation protein. Ehrlichial blood was detected in the peripheral blood from 12 (10%) of the 118 patients investigated by PCR. When the 12 amplicons from the positive cases were sequenced, they were found to be identical to each other and to the corresponding dsb sequence of an Arkansas strain of E. chaffeensis. The 12 patients who were PCR-positive for E. chaffeensis suffered from fever (100%), headache (67%), myalgia (42%), arthralgia (58%), pulmonary involvement (17%) and/or a diffuse rash (17%).

An African perspective on Helicobacter pylori: prevalence of human infection, drug resistance, and alternative approaches to treatment.

Helicobacter pylori is a Gram-negative, micro-aerophilic, motile, curved rod that inhabits the gastric mucosa of the human stomach. It chronically infects thousands of millions of people world-wide, and is one of the most genetically diverse of bacterial species. Infection with the bacterium leads to chronic gastritis, peptic ulceration, gastric cancers and gastric mucosa-associated lymphoid-tissue (MALT) lymphoma. The prevalence of infection appears to be partly determined by geographical and socio-demographic factors, being higher in Africa than elsewhere. Current treatment, based on potent combinations that each consist of a proton-pump inhibitor and two antibiotics, is successful in 80%-90% of patients. Some undesirable side-effects, poor patient compliance and drug resistance are, however, associated with significant levels of treatment failure and with contra-indications for some patients. Antibiotic resistance in H. pylori is a growing global concern that merits the urgent attention of public-health authorities. Numerous pieces of clinical evidence have revealed that eradication of the organism from a patient results in improvement of gastritis and drastically decreases the frequency of relapse of gastric and duodenal ulcers. Natural products, including medicinal plants and honey, may offer useful alternatives in the treatment of H. pylori-related infections.

Antimicrobial resistance of bacterial agents of the upper respiratory tract of school children in Buea, Cameroon.

The study was aimed at determining bacterial agents of the upper respiratory tract and the susceptibility patterns of isolates to antibiotics. In total, 200 throat swabs were obtained from students attending different boarding schools within the Buea Municipality and screened to obtain the prevalence of respiratory pathogens and to understand the antibiotic susceptibility patterns of isolates using standard microbiological procedure and the disc-diffusion test. Of the 200 samples screened, 112 (56%) had positive cultures with the dominant bacterial pathogens being Haemophilus influenzae (20%), followed by Streptococcus pneumoniae (15%), Klebsiella pneumoniae (11%), and Staphylococcus aureus (10%). Although 56% of the isolates were recovered from females compared to 44% from males, the difference was not statistically significant (p>0.05). Sixty-seven percent of the pathogens were isolated from the age-group of 10-13 years, 19.6% from the age-group of 14-17 years, and 12.5% from the age-group of 18-21 years. Antibiotic susceptibility testing revealed that gentamicin (92%) and cefuroxime (88.4%) were the most effective antibiotics against the isolates. Generally, susceptibility ranged from 0% to 92% depending on the antibiotic and the species of microorganism. Penicillin had the highest (100%) resistance to all the isolates. The findings revealed that students living in boarding schools in the Buea Municipality were at risk of acquiring upper respiratory tract infections from their peers since the upper respiratory tract of more than 50% of the students was colonized with respiratory pathogens. Although multidrug-resistant strains of organisms were identified, gentamicin and cefuroxime are recommended as the first-line antibiotics of choice against the pathogens. There is, therefore, a need for surveillance of nasopharyngeal carriage of resistant strains of these organisms, especially H. influenzae in unhealthy school children since the vaccine is yet to be introduced in Cameroon. The findings have clinical and epidemiological significance.

Molecular characterisation of Pseudomonas aeruginosa recovered in the Buea health district of Cameroon: implications for nosocomial spread.

BACKGROUND: Pseudomonas aeruginosa is a ubiquitous gram-negative pathogen with a propensity to cause opportunistic infections in humans. Different strains of the organism could colonise patients heralding a wide spectrum of P. aeruginosa infections in the environment. OBJECTIVE: To analyse isolates of P. aeruginosa from clinical and environmental samples using the Polymerase Chain Reaction (PCR) to establish strain relatedness. METHODS: Fifty-two strains of the organism were isolated from wound swabs, urine, sputum of patients and environmental samples from the hospital environment using standard microbiological techniques and ethical consideration. Genomic DNA of the isolates was amplified with primers AF1 (5'-AGA GTT TGA TCC TGG CTCA-3') and 1541R (5'-AAG GAG GTG ATC CAG CC-3'). RESULTS: At least two bands were observed in all isolates typed and band sizes ranged from 0.07 - 1.5kb. The strains were genetically diverse, displaying profiles of 2 - 6 bands between 0.07 - 1.5kb. CONCLUSION: The study demonstrates that strain diversity could be discerned between strains of P. aeruginosa, circulating in the environment of Buea, a finding which has important epidemiological and clinical significance bearing in mind that this pathogen is highly incriminated in nosocomial infections with attendant social implications. This therefore calls for more attention in the diagnosis and management of P. aeruginosa infections in the environment of Buea, Cameroon.

Ehrlichial infection in Cameroonian canines by Ehrlichia canis and Ehrlichia ewingii.

Ehrlichia chaffeensis and Ehrlichia ewingii are agents of emerging human ehrlichioses in North America and are transmitted primarily by Amblyomma americanum ticks, while Ehrlichia canis is the globally distributed cause of canine monocytic ehrlichiosis (CME) and is transmitted by the brown dog tick, Rhipicephalus sanguineus. Although E. canis and Ehrlichia ruminantium are endemic in Africa, the presence of ehrlichial agents in dogs and ticks in Cameroon has not been investigated. The objective of this study was to determine the prevalence of ehrlichial infections in Cameronian dogs using a combination of serologic and molecular methods. Peripheral blood was collected, clinical signs and the presence or absence of ticks on dogs (n=104) presenting for various reasons at local veterinary clinics around the Mount Cameroon region were noted. IFA identified 33 dogs (32%) with antibodies reactive with E. canis, and reactivity of these sera with all major E. canis antigens (200, 140, 95, 75, 47, 36, 28, and 19-kDa) was confirmed by immunoblotting. Multicolor real-time PCR detected ehrlichial DNA (E. canis (15) and E. ewingii (2)) in 17 dogs (16.3%), all of which had attached ticks at time of presentation. The dsb amplicons (378 bp) from E. canis and E. ewingii were identical to gene sequences from North American isolates. This study identifies canine ehrlichiosis as a prevalent unrecognized cause of disease in Cameroonian canines.

Pseudomonas aeruginosa isolates recovered from clinical and environmental samples in Buea, Cameroon: current status on biotyping and antibiogram.

OBJECTIVE: The study was aimed at determining the prevalent biotypes of Pseudomonas aeruginosa in the environment of Buea and the susceptibility of isolates to antibiotics. METHODS: One hundred and fifty clinical specimens (urine, wound and sputum) collected from patients attending various health institutions in Buea, and 50 environmental swabs from furniture, appliances and surroundings of these institutions were screened for P. aeruginosa using standard microbiological and biochemical methods. Antimicrobial susceptibility of the isolates was determined by the disc diffusion assay. RESULTS: Fifty-one (25.5%) of the 200 specimens were positive for the organism with urine (30%) being the most common source of isolation. Biochemical characterization grouped the isolates into eight biotypes with biotypes B III (25.59%), B II (23.53%) and B I (21.57%) being the most prevalent. Antimicrobial susceptibility results of isolates revealed 13 antibiotype patterns based on resistance to the antimicrobial agents investigated. The resistance pattern, cefotaxime, gentamicin and tetracycline (CTX(R) GEN(R) TET(R)) was the most common (21.6%) amongst the isolates. Over 40% of the isolates exhibited multi-drug resistance to five or more antibiotics, especially environmental isolates. However, there was a significant difference (P < 0.05) in the susceptibility of isolates to ciprofloxacin (98%), amikacin (90.2%) and netilmicin (80.4%) compared with other drugs used in the study. CONCLUSION: A combination of biotyping and antibiogram, which are relatively cheap and routinely available methods in our environment, could be useful for clinical and epidemiological studies particularly in laboratories in the developing world with limited resources.

Antibiogram and plasmid profiles of Neisseria gonorrhoeae isolates from Cameroon: useful tools for epidemiological survey.

A prospective laboratory-based investigative study was carried out on clinical isolates of N. gonorrhoea to determine their antibiotic susceptibility patterns and plasmid profile using standard microbiological and molecular techniques. All the 32 isolates studied showed total resistance to penicillin, spectinomycin and amoxyclinE. On the other hand, susceptibilities of 100%, 98.6% and 98.6% were noted for ciprofloxacin, ofloxacin and norfloxacin respectively. Thirty (93.8%) of the 32 isolates were found to harbour plasmids of molecular weights ranging from 9.2 to 25.2 Mdal. Three distinct groups of N. gonorrhoea isolates were identified based on the molecular weights of the plasmids, namely, group one (9.2 Mdal), group two (12.6 Mdal) and group three (25.2 Mdal). These results suggest that different strains of N. gonorrhoea may be circulating in Fako Division of Cameroon, a finding that is of clinical and epidemiological significance.

Carriage of Vibrio species by shrimps harvested from the coastal waters of South West Cameroon.

OBJECTIVES: To determine the prevalence of Vibrio spp in unprocessed shrimps and their susceptibility to antibiotics. DESIGN: A prospective study of Vibrio spp associated with shrimps harvested from the coastal waters of South West Cameroon. SETTING: A laboratory based study at the Department of Life Sciences, University of Buea. Two hundred and thirty six shrimps harvested from the coastal towns of Limbe and Tiko, Cameroon, were examined for the prevalence of Vibrio spp using standard microbiologic procedures. The antibiotic sensitivity of isolates was determined using the Kirby-Bauer disc diffusion technique. RESULTS: Of the 236 shrimps examined, 73 (30.9%) were contaminated with Vibrio spp. Further, a total of 125 Vibrio strains were isolated from the contaminated shrimps. Of this number, 33 (26.4%) were V. cholerae, 55 (44%) V. parahaemolyticus, 34 (27.2%) V. alginolyticus and three (2.4%) V. vulnificus. Antibiotic susceptibility generally ranged from 68.8% for polymyxin B to 99.2% for gentamycin. Multiple resistant strains were noted, especially with V. parahaemolyticus and V. alginolyticus CONCLUSION: Shrimps maintain a reservoir of potential Vibrio spp in the coastal area of South West Cameroon. This finding is of epidemiologic and clinical significance.

Antibacterial effect of Zingiber officinale and Garcinia kola on respiratory tract pathogens.

OBJECTIVE: To investigate the antibacterial activity of Zingiber officinale (ginger) Garcinia kola (bitter kola) on four respiratory tract pathogens. DESIGN: A prospective study based on laboratory investigations. SETTING: Department of Life Sciences, University of Buea. Throat swabs were collected from 333 individuals with running nostrils, cough and/or catarrh in three localities of Buea namely Bokwango, Molyko and Bolifamba. Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae and Haemophilus influenzae were isolated from the specimens using standard microbiological procedures. The antibacterial activity of ethanolic extracts of ginger and bitter kola, were investigated on these pathogens using the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays. RESULTS: The extracts exhibited antibacterial activity against the pathogens. The MIC of extracts ranged from 0.0003 microg/ml to 0.7 microg/ml for ginger and 0.00008 microg/ml, to 1.8 microg/mL for bitter kola, while MBC ranged from 0.1.35 microg/ml to 2.04 microg/ml for ginger and 0.135 microg/ml to 4.2 microg/ml for bitter kola. CONCLUSION: Results indicated that extracts of ginger root and bitter kola may contain compounds with therapeutic activity.

Characterization of yeast strains for wine production: effect of fermentation variables on quality of wine produced.

Sixteen yeast strains isolated from grapefruit (Citrus paradis), orange (Citrus sinensis) and pineapple (Ananas comosus) were characterized using standard microbiological procedures. The species were identified as Saccharomyces uvarum, S. cerevisiae, S. carlbergensis, and S. ellipsoideus. Their abilities for wine production were tested by using sugar and ethanol tolerance tests. The best biochemically active strain, S. ellipsoideus, was used along with commercially available baker's yeast (S. cerevisiae) to produce wine from grapefruit, orange, and pineapple juices. After fermentation for 14 d with S. cerevisiae and 21 d with S. ellipsoideus, wines produced were compared with Baron de Valls (standard). The highest (10.47% [v/v]) and lowest (7.68% [v/v]) alcohol concentrations with corresponding residual sugar concentrations of 1.88% (w/v) and 7.7% (w/v) were produced from orange after fermentation with S. cerevisiae and S. ellipsoideus, respectively. S. ellipsoideus was found to be the best yeast strain producing wine with the highest acceptable score of 7.41 from orange. The study revealed the possibility of producing wine from our locally available fruits using simple, cheap, and adaptable technology with biochemically characterized yeast strains.

Antibiogram of Klebsiella pneumoniae isolates from Buea, Cameroon.

OBJECTIVE: To determine the antibiotic susceptibility of K. pneumoniae isolates from Buea, Cameroon. DESIGN: A prospective study of K. pneumoniae isolates from clinical samples of nosocomial origin. SETTING: A laboratory based investigative study at the Biotechnology Centres of the Universities of Buea and Yaounde 1, Cameroon, and three Buea based hospitals. K. pneumoniae isolates were obtained from sputum, wound swabs and urine and screened for their antibiogram using standard procedures. RESULTS: Results on the antibiogram showed seven distinct antibiotypes distinguished by different susceptibilities to aminoglycosides (Spectinomycin and Gentamicin), Chloramphenicol and Augmentin. All the isolates shared multi-resistance to Amoxicillin and Trimethoprim. However, the isolates showed marked susceptibilities to Norfloxacin (90.01%), Cefuroxime (95.45%) and Ciprofloxacin (86.36%). CONCLUSION: The study has revealed that K. pneumoniae isolates in the environment of Buea, Cameroon are multi-drug resistant. This finding is of clinical and epidemiological significance.