Christian G Meyer

Physician; independent researcher / consultant - infectious disease specialist - editor

Background Typhoid Fever remains a major cause of morbidity and mortality in low-income settings. The Severe Typhoid in Africa programme was designed to address regional gaps in typhoid burden data and identify populations eligible for interventions using novel typhoid conjugate vaccines. Methods A hybrid design, hospital-based prospective surveil...

This is the orbituary of Prof. Dr. Christian Meyer who has suddenly passed away on a flight to Hanoi. He was on his way to do what he loved most - research, discuss and provide guidance to his dear colleagues. Thank you for beeing an important part of his life. This has been posted by Daniel Meyer, nephew of Christian. The Account will be removed...

Occult hepatitis B infection (OBI) is characterized by the presence of low levels of hepatitis B virus (HBV) DNA and undetectable HBsAg in the blood. The prevalence of OBI in blood donors in Asia ranges from 0.013% (China) to 10.9% (Laos), with no data available from Vietnam so far. We aimed to investigate the prevalence of OBI among Vietnamese blo...

Background Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality worldwide. It is a highly heterogeneous disease with poor prognosis and limited treatment options, which highlights the need for reliable biomarkers. This study aims to explore molecular markers that allow stratification of HCC and may lead to better p...

Knowledge of the clinical presentation of central nervous system (CNS) infections and the causative pathogens is crucial for appropriate diagnosis and rapid initiation of appropriate treatment to prevent severe neurological sequelae. The aim of this study is to understand the aetiology of CNS infections based on the clinical presentation of Vietnam...

Aim The aim of the present study is to compare the performance of 16S rRNA Nanopore sequencing and conventional culture in detecting infectious pathogens in patients with suspected meningitis in a resource-limited setting without extensive bioinformatics expertise. Methods DNA was isolated from the cerebrospinal fluid (CSF) of 30 patients with sus...

Objectives : Host genetic factors contribute to the variable severity of COVID-19. We examined genetic variants from genome-wide association studies (GWASs) and candidate gene association studies in a cohort of COVID-19 patients and investigated the role of early SARS-CoV-2 strains in COVID-19 severity. Methods : This case-control study included 1...

The COVID-19 pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) poses an unprecedented challenge to humanity. SARS-CoV-2 infections range from asymptomatic to severe courses of COVID-19 with acute respiratory distress syndrome (ARDS), multiorgan involvement and death. Risk factors for disease severity include older...

Background Blood stream infections (BSI) caused by Extended Spectrum Beta-Lactamases (ESBLs) producing Enterobacteriaceae is a clinical challenge leading to high mortality, especially in developing countries. In this study, we sought to describe the epidemiology of ESBL-producing Escherichia coli strains isolated from Vietnamese individuals with BS...

Background: The etiology and optimal clinical management of acute febrile illness (AFI) is poorly understood. Methods: Blood samples taken from study participants with acute fever (≥37.5°C) or a history of fever and recruited into the previous Typhoid-Fever-Surveillance-in-Africa (TSAP) study were evaluated using a polymerase chain reaction (PCR...

Despite decades of research and advancements in diagnostics and treatment, tuberculosis remains a major public health concern. New computational methods are needed to interrogate the intersection of host- and bacterial genomes. Paired host genotype datum and infecting bacterial isolate information were analysed for associations using a multinomial...

Indirect effects of the COVID-19 pandemic have the potential to seriously undermine the health system in sub-Saharan Africa with an increase in the incidences of malaria, tuberculosis (TB) and HIV infections. Based on current evidence in the African region the collateral impact of COVID-19 on the “big three diseases” shall be addressed in the follo...

Hepatitis delta virus (HDV) coinfection will additionally aggravate the hepatitis B virus (HBV) burden in the coming decades, with an increase in HBV-related liver diseases. Between 2018 and 2019, a total of 205 HBV patients clinically characterized as chronic hepatitis B (CHB; n = 115), liver cirrhosis (LC; n = 21), and hepatocellular carcinoma (H...

Background HIV-infection, tuberculosis and malaria are the big three communicable diseases that plague sub-Saharan Africa. If these diseases occur as co-morbidities they require polypharmacy, which may lead to severe drug-drug-gene interactions and variation in adverse drug reactions, but also in treatment outcomes. Polymorphisms in genes encoding...

The complement system may be crucial during dengue virus infection and progression to severe dengue. This study investigates the role of MBL2 genetic variants and levels of MBL in serum and complement proteins in Vietnamese dengue patients. MBL2 genotypes (- 550L/H, MBL2 codon 54), MBL2 diplotypes (XA/XO, YA/XO) and MBL2 haplotypes (LXPB, HXPA, XO)...

While successful containment measures of COVID-19 in China and many European countries have led to flattened curves, case numbers are rising dramatically in other countries, with the emergence of a second wave expected. Asymptomatic individuals carrying SARS-CoV-2 are hidden drivers of the pandemic, and infectivity studies confirm the existence of...

The hepatitis E virus (HEV) is one of the most common causes of hepatitis worldwide. HEV is also widespread in many developed countries, where the number of infections is steadily increasing. In those countries, the virus is transmitted mainly through consumption of undercooked or raw food or through contact with animals. Especially pigs serve as a...

The aim of this study was to assess whether epidemics of sexually transmitted infections caused by poorly transmittable agents corresponded to self-reported sexual activity in a distinct population. To exemplify this, a model was used to investigate whether HIV infection incidences corresponded to the extent of sexual activity as assessed by a ques...

Despite decades of research and advancements in diagnostics and treatment, tuberculosis remains a major public health concern, particularly in low and middle income countries. New bioinformatics and computational methods are needed to interrogate the intersection of host and bacterial genomes and identify novel targets for anti tuberculosis drugs....

Background Dengue is prevalent in as many as 128 countries with more than 100 million clinical episodes reported annually and four billion people estimated to be at risk. While dengue fever is systematically diagnosed in large parts of Asia and South America, the disease burden in Africa is less well investigated. This report describes two consecut...

The number of COVID-19 patients is increasing dramatically worldwide and treatment in intensive care units (ICU) has become a major challenge, the early recognition of severe forms of is absolutely essential for timely triaging of patients. While the clinical status, in particular Peripheral oxygen saturation (SpO2) levels and concurrent comorbidit...

SMYD3 (SET and MYND domain-containing protein 3) is involved in histone modification, which initiates oncogenesis by activating transcription of multiple downstream genes. To investigate associations of variable numbers of tandem repeats (VNTR) variants in the SMYD3 gene promoter, SMYD3 serum levels and SMYD3 mRNA expression in hepatitis B virus (H...

The current outbreak of the novel coronavirus Covid‐19 (coronavirus disease 2019; previously 2019‐nCoV), epi‐centered in Hubei Province of the People's Republic of China, has spread to many other countries. On January 30, 2020, the WHO Emergency Committee declared a global health emergency based on growing case notification rates at Chinese and int...

Background: ISGylation is the conjugation of ISG15 with target proteins. ISGylation occurs through an enzymatic cascade, which is similar to that of ubiquitination. Through ISGylation, ISG15 can bind to proteins involved in cell proliferation and differentiation, thus promoting genesis and progression of malignancies. The present study aims to inve...

Abstract Background Vitamin D derivatives and their receptor (VDR) are potent modulators of immune responses in various diseases including malignancies as well as in metabolic and infectious disorders. The impact of vitamin D receptor polymorphisms on clinical outcomes of hepatitis B virus (HBV) infection is not well understood. This study aims to...

Introduction Accurate diagnostic methods are essential for evaluating treatment efficacy in clinical trials, including vaccine trials. Although a plethora of studies assessing novel or modified treatment options is available, clinical trials evaluating the sensitivity and specificity of diagnostic methods in compliance with the demands of drug regi...

Background: Invasive salmonellosis is a common community-acquired bacteremia in persons residing in sub-Saharan Africa. However, there is a paucity of data on severe typhoid fever and its associated acute and chronic host immune response and carriage. The Severe Typhoid Fever in Africa (SETA) program, a multicountry surveillance study, aimed to ad...

Background: Antimicrobial resistance (AMR) is a major global health concern, yet, there are noticeable gaps in AMR surveillance data in regions such as sub-Saharan Africa. We aimed to measure the prevalence of extended-spectrum β-lactamase (ESBL) producing Gram-negative bacteria in bloodstream infections from 12 sentinel sites in sub-Saharan Afric...

Background: Robust household sampling, commonly applied for population-based investigations, requires sampling frames or household lists to minimize selection bias. We have applied Google Earth Pro satellite imagery to constitute structure-based sampling frames at sites in Pikine, Senegal; Pietermaritzburg, South Africa; and Wad-Medani, Sudan. Her...

Background HEV infection can occur through consumption of undercooked pork meat or exposure to animal faeces. As there are scarce data only in developing countries, we assessed whether pigs might be a potential source of human HEV infections in Vietnam. In addition, we determined anti-HEV seroprevalences in the general population and in individuals...

Background: Clinical progression of HBV-related liver diseases is largely associated with the activity of HBV-specific T cells. Soluble fibrinogen-like protein 2 (sFGL2), mainly secreted by T cells, is an important effector molecule of the immune system.

The influence of area-based socioeconomic (SE) conditions on environmental quality conditions has recently been reported showing the precise spatial relationship between area-based SE conditions and neighborhood environmental quality in an urban area in a low-income setting. Nonetheless, there is still a lack of understanding of the nature of the r...

Kenya has, in the last decade, made tremendous progress in the fight against malaria. Nevertheless, continued surveillance of the genetic diversity and population structure of Plasmodium falciparum is required to refine malaria control and to adapt and improve elimination strategies. Twelve neutral microsatellite loci were genotyped in 201 P. falci...

Objectives: To determine potential associations of the rs2296651 variant (c.800C > T, S267F) of NTCP with HBV and HBV plus concomitant HDV infection as well as with the progression of related liver diseases. Methods: The S267F variant was genotyped by DNA sequencing in 620 HBV-infected patients and 214 healthy controls (HCs). Among the patients, 45...

Plasmodium falciparum histidine-rich proteins 2 (PfHRP2) based RDTs are advocated in falciparum malaria-endemic regions, particularly when quality microscopy is not available. However, diversity and any deletion in the pfhrp2 and pfhrp3 genes can affect the performance of PfHRP2-based RDTs. A total of 400 samples collected from uncomplicated malari...

Background Transcriptomic research of blood cell lineages supports the understanding of distinct features of the immunopathology in human malaria. Methods We used microarray hybridization, validated by real-time RT-PCR to analyze whole blood gene expression in healthy Gabonese children and children with various conditions of Plasmodium falciparum...

Introduction The objective of the Health Population Africa (HPAfrica) study is to determine health behaviour and population-based factors, including socioeconomic, ethnographic, hygiene and sanitation factors, at sites of the Severe Typhoid Fever in Africa (SETA) programme. SETA aims to investigate healthcare facility-based fever surveillance in Bu...

There is paucity of data regarding the geographical distribution, incidence, and phylogenetics of multi-drug resistant (MDR) Salmonella Typhi in sub-Saharan Africa. Here we present a phylogenetic reconstruction of whole genome sequenced 249 contemporaneous S. Typhi isolated between 2008-2015 in 11 sub-Saharan African countries, in context of the 2,...

Background Clinical progression of HBV-related liver diseases is largely associated with the activity of HBV-specific T cells. Soluble fibrinogen-like protein 2 (sFGL2), mainly secreted by T cells, is an important effector molecule of the immune system. Methods sFGL2 levels were determined by ELISA assays in sera of 296 HBV patients clinically cla...

Rapid diagnostic tests (RDT) are valuable tools that support prudent and timely use of antimalarial drugs, particularly if reliable microscopy is not available. However, the performance and reliability of these tests vary between and within geographical regions. The present study evaluated the performance of routine malaria RDT in Kenyan febrile pa...

Interferon-stimulated gene 20 kDa protein (ISG20) with 3' to 5' exonuclease activity mainly targeting single-stranded RNA plays an important role in immune responses against various infectious pathogens, including hepatitis viruses. ISG20 levels were measured by ELISA assays in sera of 339 hepatitis B-virus (HBV) infected patients and 71 healthy in...

Introduction: German sex workers have illegally established a prevention strategy, which consists of testing potential sexual partners with human immunodeficiency virus (HIV)-specific rapid diagnostic tests (RDTs) prior to engaging in unprotected sexual intercourse eventually performed in case of a negative test result. Based on a recently establis...

Hepatitis D caused by the hepatitis delta virus (HDV) is a serious health problem in many regions of the world. A total of 546 HBV-infected patients were enrolled from 2013 to 2015 and classified clinically into the subgroups of chronic hepatitis B (CHB, n = 191), liver cirrhosis (LC, n = 147) and hepatocellular carcinoma (HCC, n = 208). The patien...

Background: The WHO recently prequalified a typhoid conjugate vaccine (TCV), recommending its use in persons aged ≥6 months to 45 years residing in typhoid fever (TF)-endemic areas. We now need to consider how TCVs can have the greatest impact in the most vulnerable populations in Africa. Methods: The Typhoid Fever Surveillance in Africa Program...

Background Circulating microRNAs (miRNA) are biomarkers for several neoplastic diseases, including hepatocellular carcinoma (HCC). We performed a literature search, followed by experimental screening and validation in order to establish a miRNA panel in combination with the assessment of alpha-fetoprotein (AFP) levels and to evaluate its performanc...

Levels of miRNAs and AFP in subgroups of patients with different tumor sizes. (DOC)

Primers used for cDNA synthesis and quantitation of microRNAs. (DOC)

Relationship between miRNA and ALT levels. (DOC)

Ct value and relative expression of miRNAs in the screening phase. (DOC)

Serum level of mir-192 was contradictory to Barcelona Clinic Liver Cancer staging. (DOC)

The correlation between expression level of miR-21, miR-122, miR192 and study subjects’ age. (DOC)

Differential expression of individual miRNAs used in screening phase. (DOC)

Correlation between circulating levels of microRNAs and AFP levels. (DOC)

Risk populations for HIV infections tend to neglect condom use, making alternative preventive approaches necessary. Accordingly, we modelled the risk of sexual HIV transmission for condom use vs. use of rapid diagnostic test (RDT) systems with subsequent exclusion of potential sexual partners with a correctly or falsely positive test from unprotect...

The secosteroid hormone vitamin D has, in addition to its effects in bone metabolism also functions in the modulation of immune responses against infectious agents and in inhibiting tumorigenesis. Thus, deficiency of vitamin D is associated with several malignancies, but also with a plethora of infectious diseases. Among other communicable diseases...

The genetic diversity of glutamate-rich protein (GLURP) R2 region in Plasmodium falciparum isolates collected before and 12 years after the introduction of artemisinin combination treatment of malaria in Osogbo, Osun State, Nigeria, was compared in this study. Blood samples were collected on filter paper in 2004 and 2015 from febrile children from...

AIM To investigate possible effects of IRF5 polymorphisms in the 3’ UTR region of the IFR5 locus on susceptibility to hepatitis B virus (HBV) infection and progression of liver diseases among clinically classified Vietnamese patients. METHODS Four IFR5 SNPs (rs13242262A/T, rs77416878C/T, rs10488630A/G, and rs2280714T/C) were genotyped in clinicall...

Complement is an essential element in both innate and acquired immunity contributing to the immunopathogenesis of many disorders, including Chagas Disease (CD). Human complement receptor 1 (CR1) plays a role in the clearance of complement opsonized molecules and may facilitate the entry of pathogens into host cells. Distinct CR1 exon 29 variants ha...

This study assesses the prevalence of asymptomatic Plasmodium falciparum parasitemia positivity and P. falciparum dihydrofolate reductase (pfdhfr) mutations in parasite isolates among pregnant women in Southwest Nigeria. Plasmodium falciparum parasitemia was confirmed by microscopy and nested PCR in 200 pregnant women attending antenatal care. The...

Introduction: For the identification of bacterial pathogens, blood culture is still the gold standard diagnostic method. However, several disadvantages apply to blood cultures, such as time and rather large volumes of blood sample required. We have previously established an optimised multiplex real-time PCR method in order to diagnose bloodstream...

Objective: Interleukin-10 (IL-10) is an anti-inflammatory cytokine produced by Th1 cells and macrophages. The rationale of this study was to examine and validate possible contributions of IL-10 promoter polymorphisms in sub-Saharan Africa in children infected with either Plasmodium falciparum or Schistosoma haematobium and in children co-infected...

Tuberculosis (TB) is a major threat to human health, especially in many developing countries. Human genetic variability has been recognized to be of great relevance in host responses to Mycobacterium tuberculosis infection and in regulating both the establishment and the progression of the disease. An increasing number of candidate gene and genome-...