Hepatitis E virus infections among patients with acute febrile jaundice in two regions of Cameroon: First molecular characterization of hepatitis E virus genotype 4.

BACKGROUND: Febrile jaundice is a common indicator of certain infectious diseases, including hepatitis E. In Cameroon, the yellow fever virus is the only pathogen that is monitored in patients who present with this symptom. However, more than 90% of the samples received as part of this surveillance are negative for yellow fever. This study aimed to describe the prevalence and hepatitis E virus (HEV) genotype among yellow fever-negative patients in the Far North and West regions of Cameroon. METHODS: In a cross-sectional study, yellow fever surveillance-negative samples collected between January 2021 and January 2023 were retrospectively analyzed. Anti-HEV IgM and IgG antibodies were tested using commercially available ELISA kits. Anti-HEV IgM and/or IgG positive samples were tested for HEV RNA by real-time RT-PCR, followed by nested RT-PCR, sequencing and phylogenetic analysis. RESULTS: Overall, 121 of the 543 samples (22.3%, 95% CI: 19.0% - 26.0%) were positive for at least one anti-HEV marker. Amongst these, 8.1% (44/543) were positive for anti-HEV IgM, 5.9% (32/543) for anti-HEV IgG, and 8.3% (45/544) for both markers. A total of 15.2% (12/79) samples were positive for HEV RNA real-time RT-PCR and 8 samples were positive for HEV RNA by nested RT-PCR. Phylogenetic analysis showed that the retrieved sequences clustered within HEV genotypes/subtypes 1/1e, 3/3f and 4/4b. CONCLUSION: Our results showed that HEV is one of the causes of acute febrile jaundice in patients enrolled in the yellow fever surveillance program in two regions of Cameroon. We described the circulation of three HEV genotypes, including two zoonotic genotypes. Further studies will be important to elucidate the transmission routes of these zoonotic HEV genotypes to humans in Cameroon.

Global prevalence of hepatitis B virus serological markers among healthcare workers: A systematic review and meta-analysis.

BACKGROUND: The hepatitis B virus (HBV) infection is a global public health concern that affects about 2 billion people and causes 1 million people deaths yearly. HBV is a blood-borne disease and healthcare workers (HCWs) are a high-risk group because of occupational hazard to patients' blood. Different regions of the world show a highly variable proportion of HCWs infected and/or immunized against HBV. Global data on serologic markers of HBV infection and immunization in HCWs are very important to improve strategies for HBV control. AIM: To determine the worldwide prevalence of HBV serological markers among HCWs. METHODS: In this systematic review and meta-analyses, we searched PubMed and Excerpta Medica Database (Embase) to identify studies published between 1970 and 2019 on the prevalence of HBV serological markers in HCWs worldwide. We also manually searched for references of relevant articles. Four independent investigators selected studies and included those on the prevalence of each of the HBV serological markers including hepatitis B surface antigen (HBsAg), hepatitis e antigen (HBeAg), immunoglobulin M anti-HBc, and anti-HBs. Methodological quality of eligible studies was assessed and random-effect model meta-analysis resulted in the pooled prevalence of HBV serological markers HBV infection in HCWs. Heterogeneity (I²) was assessed using the χ² test on Cochran's Q statistic and H parameters. Heterogeneity' sources were explored through subgroup and metaregression analyses. This study is registered with PROSPERO, number CRD42019137144. RESULTS: We reviewed 14059 references, out of which 227 studies corresponding to 448 prevalence data among HCWs (224936 HCWs recruited from 1964 to 2019 in 71 countries) were included in this meta-analysis. The pooled seroprevalences of current HBsAg, current HBeAg, and acute HBV infection among HCWs were 2.3% [95% confidence interval (CI): 1.9-2.7], 0.2% (95%CI: 0.0-1.7), and 5.3% (95%CI: 1.4-11.2), respectively. The pooled seroprevalences of total immunity against HBV and immunity acquired by natural HBV infection in HCWs were 56.6% (95%CI: 48.7-63.4) and 9.2% (95%CI: 6.8-11.8), respectively. HBV infection was more prevalent in HCWs in low-income countries, particularly in Africa. The highest immunization rates against HBV in HCWs were recorded in urban areas and in high-income countries including Europe, the Eastern Mediterranean and the Western Pacific. CONCLUSION: New strategies are needed to improve awareness, training, screening, vaccination, post-exposure management and treatment of HBV infection in HCWs, and particularly in low-income regions.

First molecular characterization of the hepatitis E virus in humans in Cameroon: Confirmation of the HEV outbreak in Touboro, North-Cameroon.

Hepatitis E virus (HEV) is a major causative agent of acute viral hepatitis in many regions of the world including Africa. In Cameroon, there is no published molecular study on HEV in humans. However, based on serological assays, the first outbreak of HEV was detected in North-Cameroon. The objective of this study was to determine the molecular characterization of HEV that circulated during this period. A retrospective study design was used to select serum samples among those collected during the outbreak period. immunoglobulin M positive samples available in sufficient volumes to amplify HEV RNA were selected. RNA was extracted and then amplified by a real-time reverse transcription polymerase chain reaction (real time RT-PCR) assay, followed by a nested reverse transcription polymerase chain reaction (nested RT-PCR) assay for sequencing and phylogenetic analysis. Overall, 24 samples were selected and HEV RNA was amplified by real-time RT-PCR in 20 samples. Amongst these, 12 samples were positive for HEV RNA by nested RT-PCR and yielded good sequencing products. Phylogenetic analysis showed that 10 samples clustered with HEV genotype 1 (subtype 1e) and two samples clustered with HEV genotype 3 (subtype 3f). This study fills the gap of knowledge on the molecular epidemiology of HEV in Cameroon and confirms the first report of the hepatitis E outbreak in North-Cameroon.

Clinical signs predictive of influenza virus infection in Cameroon.

Influenza virus accounts for majority of respiratory virus infections in Cameroon. According to the World Health Organization (WHO), influenza-like illnesses (ILI) are identified by a measured temperature of ≥38°C and cough, with onset within the past 10 days. Other symptoms could as well be observed however, none of these are specific to influenza alone. This study aimed to determine symptom based predictors of influenza virus infection in Cameroon. Individuals with ILI were recruited from 2009-2018 in sentinel sites of the influenza surveillance system in Cameroon according to the WHO case definition. Individual data collection forms accompanied each respiratory sample and contained clinical data. Samples were analyzed for influenza using the gold standard assay. Two statistical methods were compared to determine the most reliable clinical predictors of influenza virus activity in Cameroon: binomial logistic predictive model and random forest model. Analyses were performed in R version 3.5.2. A total of 11816 participants were recruited, of which, 24.0% were positive for influenza virus. Binomial logistic predictive model revealed that the presence of cough, rhinorrhoea, headache and myalgia are significant predictors of influenza positivity. The prediction model had a sensitivity of 75.6%, specificity of 46.6% and AUC of 66.7%. The random forest model categorized the reported symptoms according to their degree of importance in predicting influenza virus infection. Myalgia had a 2-fold higher value in predicting influenza virus infection compared to any other symptom followed by arthralgia, head ache, rhinorrhoea and sore throat. The model had a OOB error rate of 25.86%. Analysis showed that the random forest model had a better performance over the binomial regression model in predicting influenza infection. Rhinorrhoea, headache and myalgia were symptoms reported by both models as significant predictors of influenza infection in Cameroon. These symptoms could be used by clinicians in their decision to treat patients.

Evaluation of a mobile health approach to improve the Early Warning System of influenza surveillance in Cameroon.

BACKGROUND: Rapid reporting of surveillance data is essential to better inform national prevention and control strategies. OBJECTIVES: We compare the newly implemented smartphone-based system to the former paper-based and short message service (SMS) for collecting influenza epidemiological data in Cameroon. METHODS: Of the 13 sites which collect data from persons with influenza-like illness (ILI), six sites send data through the EWS, while seven sites make use of the paper-based system and SMS. We used four criteria for the comparison of the data collection tools: completeness, timeliness, conformity and cost. RESULTS: Regarding the different collection tools, data sent by the EWS were significantly more complete (97.6% vs 81.6% vs 44.8%), prompt (74.4% vs n/a vs 60.7%) and of better quality (93.7% vs 76.1% vs 84.0%) than data sent by the paper-based system and SMS, respectively. The average cost of sending a datum by a sentinel site per week was higher for the forms (5.0 USD) than for the EWS (0.9 USD) and SMS (0.1 USD). The number of outpatient visits and subsequently all surveillance data decreased across the years 2017-2019 together with the influenza positivity rate from 30.7% to 28.3%. Contrarily, the proportion of influenza-associated ILI to outpatient load was highest in the year 2019 (0.37 per 100 persons vs 0.28 and 0.26 in the other 2 years). CONCLUSION: All sentinel sites and even other disease surveillance systems are expected to use this tool in the near term future due to its satisfactory performance and cost.

Serological and molecular investigation of hepatitis E virus in pigs reservoirs from Cameroon reveals elevated seroprevalence and presence of genotype 3.

BACKGROUND: Hepatitis E virus (HEV) is a zoonotic pathogen of which pigs have been established as reservoirs. In the present study, we investigated the presence of HEV among pigs in the Center and Littoral regions of Cameroon and performed the molecular characterization of positive strains. METHODOLOGY: A total of 453 serum and stool samples were randomly collected from pigs in slaughterhouses in Obala, Douala and Yaounde. All samples were examined for the presence of anti-HEV IgG and IgM antibodies using ELISA assays. IgM positive stool samples were tested for HEV RNA using an RT-PCR assay, followed by a nested PCR assay for sequencing and phylogenetic analysis. RESULTS: Overall, 216 samples (47.7%, 95% CI: 43.1%-52.3%) were positive for at least one of the serological markers of HEV infection. Amongst these, 21.0% were positives for anti-HEV IgM, 17.7% for anti-HEV IgG, and 9.1% for both. A total of eight stool samples (5.9%) were positive for HEV RNA by nested RT-PCR. Phylogenetic analysis showed that the retrieved sequences clustered within HEV genotype 3. CONCLUSION: This study shows a high prevalence of anti-HEV antibodies and the circulation of genotype 3 in the swine population in Cameroon. Subsequent studies will be needed to elucidate the zoonotic transmission of HEV from pigs to humans in Cameroon.

Circulation of influenza virus from 2009 to 2018 in Cameroon: 10 years of surveillance data.

Since the recent emergence of several subtypes of influenza viruses with pandemic potentials, there has been growing interest on the control of this infection worldwide. This study aimed to describe the 10 years of influenza activity in Cameroon between January 2009 and December 2018. Respiratory samples were collected from sentinel sites responsible for influenza surveillance in Cameroon and analyzed for the presence of influenza. Globally, 9 of the 10 administrative regions of the country were represented with at least 1 year of data. A total of 11816 respiratory samples were collected and influenza virus detection rate was 24.0%. The most represented age group was the 0-1 years representing more than 40% of the collected samples and possessing the lowest proportion of influenza cases (16.2%). Meanwhile higher proportions of influenza positive cases was found in the 2-4, 5-14 and 15-49 years age group at ≥29%. Among outpatients, the frequency of influenza virus was 24.8% while in hospitalized patients, 18.7% of samples were positive for influenza virus. We noted year-round circulation of influenza virus in Cameroon with 2 peaks in activity: a major peak in the months of September to December and a minor peak in the months of March to July. Antigenic characterization of influenza isolates showed 37.5% (6/16) vaccine match between the predominant Cameroon strains and the Northern hemisphere vaccine strains with majority of vaccine match observed in influenza B/Victoria subtype (4/6; 66.7%). Data collected from this surveillance system is essential to add to global information on the spread of influenza.

Molecular characterization of measles virus strains circulating in Cameroon during the 2013-2016 epidemics.

The first genotyping data on measles virus (MeV) strains in Cameroon dates from 1994, while other studies were realized in 2001 and 2011 with the establishment of MeV virological surveillance. However, the genetic data of MeV strains circulating in Cameroon remains fragmented and concentrated in certain regions, hence the need for an update. The objective of this study was to have recent data on MeV genotypes circulating in Cameroon. Ninety throat swabs collected during recent measles outbreaks were analyzed by MeV genotyping RT-PCR using the nucleoprotein gene N. The resulting sequences were analyzed on the basis of 450 nucleotides with MEGA 7 software. Overall genome analysis was performed on 40/90 sequences. The strains were from all ten regions and all belonged to cluster 1 of genotype B3. The genotype B3 has been circulating in Cameroon for long periods of time; efforts must be made in immunization for its elimination.

Evolutionary trends in the prevalence of anti-HDV antibodies among patients positive for HBsAg referred to a national laboratory in Cameroon from 2012 to 2017.

OBJECTIVE: The aim of this study was to update the data on the prevalence of anti-HDV antibodies in Cameroon. RESULTS: Antibodies against hepatitis Delta virus (Anti-HDV) were found in 16.48% (95% CI 11.46-18.77%) of 426 hepatitis B virus surface antigen positive patients in Cameroon. Remarkably, they were significantly higher among people over 40 years and those living in the East and South regions of Cameroon at 66.7%, 50%, and 40%, respectively. These results suggest that older age and living in areas in the dense forest may be risk factors for Hepatitis D infection.

Detection of hepatitis E virus antibodies among Cercopithecidae and Hominidae monkeys in Cameroon.

We screened hepatitis E from 15 species of non-human primates. Anti-HEV IgG was detected in 11.1% (1/9) Mandrillus sphinx, 14.3% (2/14) Gorilla gorilla, 5.9% (4/67) pan troglodytes and 8.7% (2/23) Mandrillus leucophaeus, whereas anti-HEV IgM was detected in 1.5% (1/18) papio Anubis, 28.6% (2/7) Cercocebus agilis and 1.5% (1/67) pan troglodyte.

Genetic diversity of influenza A(H3N2) viruses in Northern Cameroon during the 2014-2016 influenza seasons.

In Cameroon, genome characterization of influenza virus has been performed only in the Southern regions meanwhile genetic diversity of this virus varies with respect to locality. The Northern region characterized by a Sudan tropical climate might have distinct genetic characterization. This study aimed to better understand the genetic diversity of influenza A(H3N2) viruses circulating in Northern Cameroon. Sequences of three gene segments (hemagglutinin (HA), neuraminidase (NA) and matrix (M) genes) were obtained from 16 A(H3N2) virus strains collected during the 2014 to 2016 influenza seasons in Garoua. The HA gene segments were analysed with respect to reference strains while the NA and M gene was analysed for reported genetic markers of resistance to antivirals. Analysis of the HA sequences revealed that majority of the virus strains grouped together with the 2016-2017 vaccine strain (3C.2a-A/Hong Kong/4801/2014) while 3/5 (60%) of the 2015 viral strains grouped together with the 2015-2016 vaccine strain 3C.3a-A/Switzerland/9715293/2013. Within clade 3C.2a, Northern Cameroon sequences mostly grouped in sub-clade A3 (10/16). Analysis of the coding regions of the NA and M genes showed that none had genetic markers of resistance to neuraminidase inhibitors but all strains possessed the S31N substitution of resistance to amantadine. Due to some discrepancies observed in this region with respect to the Southern regions of Cameroon, there is necessity of including all regions within a country in the sentinel surveillance of influenza. These data will enable to track changes in influenza viruses in Cameroon.

First report of the genomic characterization of rubella viruses circulating in Cameroon.

Rubella is an acute and contagious viral infection whose gravidity resides in infection during pregnancy, which can result in miscarriage, fetal death, stillbirth, or infants with congenital malformations. This study aimed to describe the genome of rubella viruses (RUBVs) circulating in Cameroon. Throat swabs were collected from health districts as part of the measles surveillance program from 2010 to 2016 and sent to the Centre Pasteur of Cameroon. Samples were amplified by genotyping reverse transcription polymerase chain reaction (RT-PCR) in the search of two overlapping fragments of the gene that encodes the E1 envelope glycoprotein of RUBV. PCR products were sequenced and phylogenetic analysis was performed with MEGA 6 software. Overall, 9 of 43 samples (20.93%) were successfully amplified and sequenced but only eight sequences could be exploited for phylogenetic analysis with respect to the required fragment length of 739 nucleotides. Analysis of viral sequences from Cameroon with other epidemiologically relevant sequences from around the world showed that all RUBVs belonged to lineage L1 of genotype 1G. Cameroon sequences clustered with viruses from West Africa including Nigeria, Ivory Coast, and Ghana with a percentage similarity of 95.4% to 99.2%. This study will enable an update on the molecular epidemiology of RUBV in Cameroon and help in monitoring circulating RUBV for a better implementation of elimination strategies.

Evidence of exposure and human seroconversion during an outbreak of avian influenza A(H5N1) among poultry in Cameroon.

From May 2016 to March 2017, 22 poultry outbreaks of avian influenza A(H5N1) were reported in Cameroon, mainly in poultry farms and live bird markets. No human cases were reported. In this study, we sought to describe the 2016 A(H5N1) outbreak strain and to investigate the risk of infection in exposed individuals. We find that highly pathogenic influenza subtype A(H5N1), clade 2.3.2.1c from Cameroon is closely related phylogenetically and antigenically to strains isolated in central and western Africa at the time. No molecular markers of increased human transmissibility were noted; however, seroconversion was detected in two poultry workers (1.5% of total screened). Therefore, the continued outbreaks of avian influenza in poultry and the risk of zoonotic human infection highlight the crucial need for continued and vigilant influenza surveillance and research in Africa, especially in areas of high poultry trade, such as Cameroon.

Molecular characterization of influenza A(H1N1)pdm09 in Cameroon during the 2014-2016 influenza seasons.

In 2009, Influenza A(H1N1)pdm09 caused the first influenza pandemic of the 21st century with high mortality rates of about 284 500 deaths. This virus, however, continues to circulate as a seasonal influenza virus and to cause illness and deaths worldwide. In this study, we describe the genetic diversity of A(H1N1)pdm09 viruses collected between 2014 and 2016 in Cameroon. Three gene segments (HA, NA and M) of Cameroon strains were studied. The phylogenetic tree of the coding nucleotide sequences was generated by MEGA version 6.0 using a Maximum Likelihood method. The NA and M protein coding sequences were analyzed for the reported genetic markers of resistance against neuraminidase inhibitors and adamantanes, while predicted vaccine efficacy was estimated using the Pepitope method. Overall 39 strains were obtained. Phylogenetic analysis of the HA gene of influenza A(H1N1)pdm09 showed that Cameroon strains belonged to two major clades. The 2014 Cameroon sequences belonged to clade 6C while all sequences collected between 2015 and 2016 belonged to clade 6B. Majority of the samples had some mutations in the NA gene notably: I117M, N248D, and N369K while the amantadine-resistant M mutant, S31N, was found to be absent only in the two sequences collected in 2014. Overall, A/California/07/2009 vaccine strain showed a predicted vaccine efficacy of 24.55% to 35.77% against Cameroon A(H1N1)pdm09 strains circulating between 2014 and 2016. Our findings confirms the fast evolution of A(H1N1)pdm09 since its first introduction and highlights on the importance of influenza vaccine in reducing the burden caused by influenza in the community.

Influence of meteorological parameters in the seasonality of influenza viruses circulating in Northern Cameroon.

BACKGROUND: Several studies have demonstrated the role of meteorological parameters in the seasonality of influenza viruses in tropical and subtropical regions, most importantly temperature, humidity, and rainfall. OBJECTIVES: This study aimed to describe the influence of meteorological parameters in the seasonality of influenza viruses in Northern Cameroon, a region characterized by high temperatures. METHODS: This was a retrospective study performed in Garoua Cameroon from January 2014 to December 2016. Monthly proportions of confirmed influenza cases from six sentinel sites were considered as dependent variables, whereas monthly values of mean temperature, average relative humidity, and accumulated rainfall were considered as independent variables. A vector error correction model was used to determine the relationship between influenza activity and the meteorological variables. RESULTS AND CONCLUSION: Analysis showed that there was a statistically significant association between overall influenza activity and influenza A activity with respect to average relative humidity. A unit increase in humidity within a given month leads to more than 85% rise in the overall influenza and influenza A activity 2 months later. Meanwhile, none of the three meteorological variables could explain influenza B activity. This observation is essential in filling the gap of knowledge and could help in the prevention and control strategies to strengthen influenza surveillance program in Cameroon.

Genetic characterization of influenza B virus in Cameroon and high frequency of reassortant strains.

Influenza B is broadly divided into B/Victoria and B/Yamagata lineages based on its genetic and antigenic properties. We describe in this study the first report on genome characterization of type B influenza virus in the Cameroon National Influenza Center (NIC) between 2014 and 2017. Respiratory samples were collected as part of the influenza surveillance activity in the NIC. RNA products were tested for the presence of influenza using the CDC Influenza A/B typing panel. Thirty-five samples positive for influenza B were selected for sequencing three gene segments (HA, NA, and M) and phylogenetic trees were generated by MEGA version 6.0. Nucleotide phylogenetic analysis of the HA gene revealed the presence of three major clades among Cameroonian strains. All Victoria lineages grouped into B/Victoria clade 1A, while, Yamagata lineages grouped into Yamagata clade 2 (2014 strains) and Yamagata clade 3 (2015-2017). We observed a high frequency of reassortant viruses with Yamagata-like HA gene and Victoria-like NA gene (27.4%; 23/84). The results from this study confirm variations in the genome composition of type B influenza virus and emphasize on the relevance of molecular surveillance for spotting peculiar genetic variants of public health and clinical significance.

Sero-prevalence of HBsAg in naive HIV-infected patients in a rural locality of Cameroon.

OBJECTIVE: This study was performed in order to fill the gap of knowledge regarding sero-epidemiology of hepatitis B virus (HBV) amongst Human Immunodeficiency virus (HIV)-infected patients and to assess the risk factors associated with HBV co-infection in a rural locality of Cameroon. A retrospective and cross-sectional study was carried out from January 2008 to April 2014 within the Mfou District Hospital. Naive HIV-infected patients were enrolled in the study and tested for hepatitis B surface antigen (HBsAg). Preliminary pre-therapeutic data essential for follow-up was collected from the participants. RESULTS: Overall, the sample size was constituted of 712 HIV-infected patients. The prevalence of HBsAg was 8.99%. A significant difference was observed in the proportion of HBsAg positive subjects with respect to the year of inclusion; higher proportions were observed between 2011 and 2014 (P-value = 0.007). Majority of HBV co-infected participants had severe immuno-suppression with CD4 counts lower than 100 cells/µL as compared to HIV mono-infected population but the difference was not statistically significant. Our results confirm the high prevalence for HBV infection among HIV-infected patients in the Mfou District Hospital. These findings will enable stake holders to be better armed in the elimination of viral hepatitis as a public health problem.

What is the best strategy for the prevention of transfusion-transmitted malaria in sub-Saharan African countries where malaria is endemic?

The transmission of malaria by blood transfusion was one of the first recorded incidents of transfusion-transmitted infections (TTIs). Although the World Health Organization (WHO) recommends that blood for transfusion should be screened for TTIs, malaria screening is not performed in most malaria-endemic countries in sub-Saharan Africa (SSA). The transfusion of infected red blood cells may lead to severe post-transfusion clinical manifestations of malaria, which could be rapidly fatal. Ensuring that blood supply in endemic countries is free from malaria is highly problematical, as most of the donors may potentially harbour low levels of malaria parasites. Pre-transfusion screening within endemic settings has been identified as a cost-effective option for prevention of transfusion-transmitted malaria (TTM). But currently, there is no screening method that is practical, affordable and suitably sensitive for use by blood banks in SSA. Even if this method was available, rejection of malaria-positive donors would considerably jeopardize the blood supply and increase morbidity and mortality, especially among pregnant women and children who top the scale of blood transfusion users in SSA. In this context, the systematic prophylaxis of recipients with anti-malarials could constitute a good alternative, as it prevents any deferral of donor units as well as the occurrence of TTM. With the on-going programme, namely the Affordable Medicine Facility - Malaria, there is an increase in the availability of low-priced artemisinin-based combination therapy that can be used for systematic prophylaxis. It appears nonetheless an urgent need to conduct cost-benefit studies in order to evaluate each of the TTM preventive methods. This approach could permit the design and implementation of an evidence-based measure of TTM prevention in SSA, advocating thereby its widespread use in the region.