Jelle Matthijnssens

• Ir. PhD
• Professor at KU Leuven

Background Alphaviruses, including chikungunya virus (CHIKV), pose a significant global health threat, yet specific antiviral therapies remain unavailable. Methods We evaluated combinations of three oral directly acting antiviral drugs (sofosbuvir (SOF), molnupiravir (MPV), and favipiravir (FAV)), which are approved for other indications, against...

Human noroviruses (HuNoVs) are a major cause of diarrheal disease, yet critical aspects of their biology, including cellular tropism, remain unclear. Although research has traditionally focused on the intestinal epithelium, the hypothesis that HuNoV infects macrophages has been recurrently discussed and is investigated here using a zebrafish larval...

Human microbiomes are essential to health throughout the lifespan and are increasingly recognized and studied for their roles in metabolic, immunological and neurological processes. Although the full complexity of these microbial communities is not fully understood, their clinical and industrial exploitation is well advanced and expanding, needing...

Conventional hospital-based infectious disease surveillance struggles to detect mild or asymptomatic infections and incurs high costs for large-scale testing during outbreaks. In contrast, environmental surveillance can effectively monitor viral circulation and capture asymptomatic or mildly symptomatic infections that may otherwise go unnoticed. T...

Parasitic nematodes have an intimate, chronic and lifelong exposure to vertebrate tissues. Here we mined 41 published parasitic nematode transcriptomes from vertebrate hosts and identified 91 RNA viruses across 13 virus orders from 24 families in ~70% (28 out of 41) of parasitic nematode species, which include only 5 previously reported viruses. We...

In Cameroon, Aedes mosquitoes transmit various arboviruses, posing significant health risks. We aimed to characterize the Aedes virome in southwestern Cameroon and identify potential core viruses which might be associated with vector competence. A total of 398 Aedes mosquitoes were collected from four locations (Bafoussam, Buea, Edea, and Yaounde)....

In Cameroon, Aedes mosquitoes transmit various arboviruses, posing significant health risks. We aimed to characterize the Aedes virome in southwestern Cameroon and identify potential core viruses which might be associated with vector competence. A total of 398 Aedes mosquitoes were collected from four locations (Bafoussam, Buea, Edea and Yaounde)....

In recent years, managed honey bee colonies have been suffering from an increasing number of biotic and abiotic stressors, resulting in numerous losses of colonies worldwide. A pan-European study, EPILOBEE, estimated the colony loss in Belgium to be 32.4% in 2012 and 14.8% in 2013. In the current study, absolute viral loads of four known honey bee...

In arthropod-associated microbial communities, insect-specific viruses (ISVs) are prevalent yet understudied due to limited infectivity outside their natural hosts. However, ISVs might play a crucial role in regulating mosquito populations and influencing arthropod-borne virus transmission. Some studies have indicated a core virome in mosquitoes co...

Introduction Despite vaccine availability, rotavirus persists as a leading cause of gastroenteritis in children under five years of age, and continued surveillance of circulating genotypes is needed to monitor their evolution. Methods We collected 8024 rotavirus positive samples throughout Belgium between 2009 and 2023. For 6352 samples we were abl...

Latent autoimmune diabetes in adults (LADA) is a heterogeneous disease characterized by autoantibodies against insulin producing pancreatic beta cells and initial lack of need for insulin treatment. The aim of the present study was to investigate if individuals with LADA have an altered gut microbiota relative to non-diabetic control subjects, indi...

Strong epidemiological evidence suggests that onchocerciasis may be associated with epilepsy – hence the name onchocerciasis-associated epilepsy (OAE). However, the pathogenesis of OAE still needs to be elucidated, as recent studies failed to detect Onchocerca volvulus in the central nervous system of persons with OAE. Therefore, it was suggested t...

Using a metagenomic sequencing approach on stool samples from children with Acute Flaccid Paralysis (AFP), we describe the genetic diversity of Sapoviruses (SaVs) in children in Nigeria. We identified six complete genome sequences and two partial genome sequences. Several SaV genogroups and genotypes were detected, including GII (GII.4 and GII.8),...

The second symposium of the Belgian Society for Viruses of Microbes (BSVoM) took place on 8 September 2023 at the University of Liège with 141 participants from 10 countries. The meeting program covered three thematic sessions opened by international keynote speakers: two sessions were devoted to “Fundamental research in phage ecology and biology”...

In arthropod-associated microbial communities, insect-specific viruses (ISVs) are prevalent yet understudied due to limited infectivity outside their natural hosts. However, ISVs might play a crucial role in regulating mosquito populations and influencing arthropod-borne virus transmission. Some studies have indicated a core virome in mosquitoes co...

Background A high prevalence of onchocerciasis-associated epilepsy (OAE) has been observed in onchocerciasis-endemic areas with high ongoing Onchocerca volvulus transmission. However, the pathogenesis of OAE remains to be elucidated. We hypothesise that the O. volvulus virome could be involved in inducing epilepsy. With this study, we aim to descri...

Patients suffering from hidradenitis suppurativa (HS) develop painful skin lesions, significantly decreasing their quality of life. This chronic disease is triggered by plugged hair follicles resulting in an aberrant immune response, skin microbiome imbalance and secondary bacterial colonization. As a result, a diversity of treatment options are cu...

Hidradenitis suppurativa (HS) is a chronic inflammatory disease characterized by recurring painful skin lesions. Despite ongoing research, the exact cause underlying the initiation and progression of disease remains unknown. While prior research has linked the skin microbiota to HS pathology, the role of viruses has remained unexplored. To investig...

Rotavirus A (RVA) causes diarrhea in calves and frequently possesses the G6 and P[5]/P[11] genotypes, whereas G8 is less common. We aimed to compare RVA infections and G/P genotypes in beef and dairy calves from major livestock regions of Argentina, elucidate the evolutionary origin of a G8 strain and analyze the G8 lineages, infer the phylogenetic...

Background: A high prevalence of onchocerciasis-associated epilepsy (OAE) has been observed in onchocerciasis-endemic areas with high ongoing Onchocerca volvulus transmission. However, the pathogenesis of OAE remains to be elucidated. We hypothesise that the O. volvulus virome could be involved in inducing epilepsy. With this study, we aim to descr...

Background West Nile virus (WNV) and Usutu virus (USUV) are emerging arthropod-borne viruses (arboviruses) in Europe transmitted by Culex mosquitoes. In Belgium, it is currently unknown which Culex species are competent vectors for WNV or USUV and if these mosquitoes carry Wolbachia, an endosymbiotic bacterium that can block arbovirus transmission....

Marine macroalgae (seaweeds) are important primary producers and foundation species in coastal ecosystems around the world. Seaweeds currently contribute to an estimated 51% of the global mariculture production, with a long-term growth rate of 6% per year, and an estimated market value of more than US$11.3 billion. Viral infections could have a sub...

We report the sequences of four complete genomes of parvovirus B19, extracted from human amniotic fluid specimens collected from pregnant women with abnormal ultrasound features in France. The genome sequences are 5,596 nucleotides long and include long terminal repeats. Several amino acid substitutions were observed in nonstructural protein (NS1).

Screening published transcriptomes, we have discovered 75 RNA viruses that infect 27 species of parasitic nematodes, responsible for >1.5 billion infections in people and animals. Our analysis shows extensive diversity and a conserved global spread of virus/nematode associations across multiple continents suggesting an ancestral acquisition event a...

Blood transfusion safety is an essential element of public health. Current blood screening strategies rely on targeted techniques that could miss unknown or unexpected pathogens. Recent studies have demonstrated the presence of a viral community (virobiota/virome) in the blood of healthy individuals. Here, we characterized the blood virome in patie...

Background West Nile virus (WNV) and Usutu virus (USUV) are emerging arboviruses in Europe transmitted by Culex mosquitoes. In Belgium, it is currently unknown which Culex species are competent vectors for WNV or USUV and if these mosquitoes carry Wolbachia , an endosymbiotic bacterium that can block arbovirus transmission. The aims of our study we...

The virome remains an understudied domain of the human microbiome. The role of commensal viruses on the outcome of infections with known pathogens is not well characterized. In this study we aimed to characterize the longitudinal plasma virome dynamics in chronic hepatitis B virus (HBV) infected patients. Eighty-five longitudinal plasma samples wer...

Introduction: Inflammatory bowel disease (IBD) is a major debilitating disease. Recently, the gut microbiota has gained attention as an important factor involved in the pathophysiology of IBD. As a complement to the established bacterial 'enterotypes' associated with IBD, we focussed on viruses. We investigated the intestinal virome of IBD patient...

Virome research is a rapidly growing area in the microbiome field that is increasingly associated with human diseases, such as inflammatory bowel disease (IBD). Although substantial progress has been made, major methodological challenges limit our understanding of the virota. In this review, we describe challenges that must be considered to accurat...

Viruses are the most abundant components of the human gut microbiome with a significant impact on health and disease. The effects of human immunodeficiency virus (HIV) infection on gut virome has been scarcely analysed. Several studies suggested that integrase strand transfers inhibitors (INSTIs) are associated with a healthier gut. Thus, the objec...

Spinareoviridae is a large family of icosahedral viruses that are usually regarded as non-enveloped with segmented (9–12 linear segments) dsRNA genomes of 23–29 kbp. Spinareovirids have a broad host range, infecting animals, fungi and plants. Some have important pathogenic potential for humans (e.g. Colorado tick fever virus), livestock (e.g. avian...

Background Inflammatory Bowel Diseases (IBD) are a group of chronic inflammatory diseases of the gut. IBD patients have an altered gut microbiota; however, the relationship to disease is unknown. The gut microbiota is a complex ecosystem and bacterial community-typing is an established approach to condense the microbial complexity into enterotypes....

Sedoreoviridae is a large family of icosahedral viruses that are usually regarded as non-enveloped with segmented (10–12 linear segments) dsRNA genomes of 18–26 kbp. Sedoreovirids have a broad host range, infecting mammals, birds, crustaceans, arthropods, algae and plants. Some of them have important pathogenic potential for humans (e.g. rotavirus...

The emergence of West Nile virus and Usutu virus in Europe poses a significant risk to public health. In the absence of efficient antiviral therapy or vaccine candidates, the only strategy to control these arboviruses is to target the Culex (Diptera: Culicidae) mosquito vector. However, the selection pressure caused by exposure to insecticides for...

In this study, we first utilized the single mosquito microbiome analysis, demonstrating a complex three-way interaction among arboviruses, resident microbiota, and the host, which is distinct for different arbovirus–mosquito combinations. Some of the previously described “core virus” increased in the mosquitos receiving viral blood meal, like Guade...

Purpose: Viruses are the most abundant components of the human gut microbiome with a significant impact on health and disease. The impact of human immunodeficiency virus (HIV) infection on the gut virome has been scarcely analysed and several studies suggested that integrase strand transfers inhibitors (INSTIs) are associated with a healthier gut....

Introduction: Viruses are the most abundant components of the human gut microbiome with a significant impact on health and disease. The impact of human immunodeficiency virus (HIV) infection on the gut virome has been scarcely analysed and several studies suggested that integrase strand transfers inhibitors (INSTIs) are associated with a healthier...

Objective IBD patients have an altered gut virome composition; however, the relationship to disease is unknown. Our aim is to investigate the existence of viral community types and assess the impact of therapeutic outcome (and other covariates) on the gut virome. Design Viral particle enrichment followed by deep sequencing (1.52 TB) was performed...

Since the introduction of live-attenuated rotavirus vaccines in Belgium in 2006, surveillance has routinely detected rotavirus vaccine-derived strains. However, their genomic landscape and potential role in gastroenteritis have not been thoroughly investigated. We compared VP7 and VP4 nucleotide sequences obtained from rotavirus surveillance with t...

INTRODUCCIÓN/OBJETIVOS Varios estudios han analizado los efectos de la infección por el virus de la inmunodeficiencia humana (VIH) y de los diferentes tratamientos antirretrovirales (TARs) sobre el componente bacteriano de la microbiota intestinal (MI) (1–6). Sin embargo, se han publicado muy pocos estudios en los que se haya analizado el impacto d...

Honey bees are globally important pollinators threatened by many different pathogens, including viruses. We investigated the virome of honey bees collected at the end of the beekeeping season (August/September) in Czechia, a Central European country. Samples were examined in biological replicates to assess the homogeneity, stability, and compositio...

Viruses are the most abundant components of the microbiome in human beings with a significant impact on health and disease. However, the impact of human immunodeficiency virus (HIV) infection on gut virome has been scarcely analyzed. On the other hand, several studies suggested that not all antiretrovirals for treating HIV infection exert similar e...

Significance Microbes colonizing the infant gut during the first year(s) of life play an important role in immune system development. We show that after birth the (nearly) sterile gut is rapidly colonized by bacteria and their viruses (phages), which often show a strong cooccurrence. Most viruses infecting the infant do not cause clinical signs and...

Characterization of gut phages in HIV-infected patients.

The emergence of West Nile virus and Usutu virus in Europe is a significant risk to public health. In the absence of efficient antiviral therapy or vaccine candidates, the only strategy to control these arboviruses is to target the Culex mosquito vector. However, the selection pressure caused by exposure to insecticides in vector control or agricul...

Acute gastroenteritis is one of the main causes of mortality and morbidity worldwide, affecting mainly children, the immunocompromised and elderly people. Enteric viruses, especially rotavirus A, are considered important etiological agents, while long-term care facilities are considered favorable environments for the occurrence of sporadic cases an...

Bivalve mollusks have been widely recognized as an important source of foodborne virus. The aim of this work was to determine the presence of norovirus (NoV) and rotavirus (RVA) in Pacific cupped oyster (Crassostrea gigas) from Buenos Aires, Argentina. A total of 88 oyster were processed. 7% of pooled samples resulted positive for NoV GII by RT-qPC...

In 1977, a sample of diseased adult honeybees ( Apis mellifera ) from Egypt was found to contain large amounts of a previously unknown virus, Egypt bee virus, which was subsequently shown to be serologically related to deformed wing virus (DWV). By sequencing the original isolate, we demonstrate that Egypt bee virus is in fact a fourth unique, majo...

After birth, microbial colonization of the infant intestinal tract is important for health later in life. However, this initial process is highly dynamic and influenced by many factors.

Rotavirus remains one of the most important causes of severe diarrhea and dehydration in young children worldwide. Although NSP1 is dispensable for rotavirus replication in cell culture, its exact role in virus infection in vivo remains unclear.

Despite the global use of rotavirus vaccines, vaccine breakthrough cases remain a pediatric health problem. In this study, we investigated suspected rotavirus vaccine breakthrough cases using next-generation sequencing (NGS) based viral metagenomics (n=102) and a panel of semi-quantitative reverse transcription PCR (RT-qPCR) (n=92) targeting known...

Gut viruses are important, yet often neglected, players in the complex human gut microbial ecosystem. Recently, the number of human gut virome studies has been increasing; however, we are still only scratching the surface of the immense viral diversity. In this study, 254 virus-enriched fecal metagenomes from 204 Danish subjects were used to genera...

Human noroviruses (HuNoVs) are the most common cause of viral gastroenteritis resulting in ~219,000 deaths annually and a societal cost of ~USD60 billion. There are no antivirals or vaccines available to treat and/or prevent HuNoV. In this study, we performed a large-scale phenotypical antiviral screening using the mouse norovirus (MNV), which incl...

There are currently no antivirals available to treat infection with enterovirus A71 (EV-A71) or any other enterovirus. The extensively studied capsid binders rapidly select for drug-resistant variants. We here explore whether the combination of two direct-acting enterovirus inhibitors with a different mechanism of action may delay or prevent resist...

Background Disturbances in the primary colonization of the infant gut can result in life-long consequences and have been associated with a range of host conditions. Although early life factors have been shown to affect the infant gut microbiota development, our current understanding of the human gut colonization in early life remains limited. To ga...

Background & aims Alcohol is the most common cause of liver-related mortality and morbidity. We therefore aimed to assess and compare the prognostic performance of elastography and blood-based markers to predict time to the first liver-related event, severe infection, and all-cause mortality in patients with a history of excess drinking. Methods P...

Viruses are the primary cause of acute gastroenteritis in children all over the world. Understanding the emergence and genetic variation of these viruses may help to prevent infections. Aichivirus (AiV) is a member of the Kobuvirus genus, which currently contains six officially recognized species: Aichivirus A-F. The species AiV A contains six type...

Culex modestus mosquitoes are considered potential transmission vectors of West Nile virus and Usutu virus. Their presence has been reported across several European countries, including one larva detected in Belgium in 2018. In this study, mosquitoes were collected in the city of Leuven and surrounding areas in the summers of 2019 and 2020. Species...

The alpaca is a very important social and economic resource for the production of fibre and meat for Andean communities. Peru is the main producer of alpacas. Group A rotavirus (RVA) has been sporadically detected in alpacas. In this study, a total of 1423 faecal samples from alpacas from different locations of the Puno department in Peru were coll...

Background: Gut viruses are important players in the complex human gut microbial ecosystem. Recently, the number of human gut virome studies is steadily increasing, however we are still only scratching the surface of the immense viral diversity as many wet lab and bio-informatics challenges remain. In this study, 254 virus-enriched faecal metagenom...

The explosively expanding COVID-19 pandemic urges the development of safe, efficacious and fast-acting vaccines. Several vaccine platforms are leveraged for a rapid emergency response1. We describe the discovery of a live virus-vectored SARS-CoV-2 vaccine candidate using the yellow fever 17D (YF17D) vaccine as vector to express a non-cleavable pref...

Bats host many viruses pathogenic to humans, and increasing evidence suggests that rotavirus A (RVA) also belongs to this list. Rotaviruses cause diarrheal disease in many mammals and birds, and their segmented genomes allow them to reassort and increase their genetic diversity. Eighteen out of 2,142 bat fecal samples (0.8%) collected from Europe,...

Culex modestus mosquitoes are known transmission vectors of West Nile virus and Usutu virus. Their presence has been reported across several European countries, including only one larva confirmed in Belgium in 2018. Mosquitoes were collected in the city of Leuven and surroundings in the summer of 2019 and 2020. Species identification was performed...

Metagenomics studies have accelerated the discovery of novel or divergent viruses of the honey bee. However, most of these studies predominantly focused on RNA viruses, and many suffer from the relatively low abundance of viral nucleic acids in the samples (i.e., compared to that of the host). Here, we explored the virome of the Ethiopian honey bee...

Our study revealed that the virome was very stable across all developmental stages of both lab-derived and field-collected Aedes albopictus . The data representing the core virome in lab A. albopictus proved the vertical transmission route of these viruses, forming a “vertically transmitted core virome.” Field mosquitoes also contained this stable...

Recent advancements in sequencing technologies and metagenomic studies have increased the knowledge of the virosphere associated with honey bees tremendously. In this study, viral-like particle enrichment and deep sequencing was deployed to detect viral communities in managed Belgian honey bees. A substantial number of previously undescribed diverg...

Bats host many viruses pathogenic to humans, and increasing evidence suggests that Rotavirus A (RVA) also belongs to this list. Rotaviruses cause diarrheal disease in many mammals and birds, and their segmented genomes allow them to reassort and increase their genetic diversity. Eighteen out of 2,142 bat fecal samples (0.8%) collected from Europe,...

The IABS-EU, in association with PROVAXS and Ghent University, hosted the “2nd Conference on Next Generation Sequencing (NGS) for Adventitious Virus Detection in Human and Veterinary Biologics” held on November 13th and 14th 2019, in Ghent, Belgium. The meeting brought together international experts from regulatory agencies, the biotherapeutics and...

Crangon crangon is economically a very important species. Recently, promising culture attempts have been made, but a major problem is the uncontrollable mortality during the grow-out phase. As of yet, the life cycle of C. crangon is not closed in captivity so wild-caught individuals are used for further rearing. Therefore, it is important to invest...

Flaviviruses encompass not only medically relevant arthropod-borne viruses (arboviruses) but also insect-specific flaviviruses (ISFs) that are presumably maintained primarily through vertical transmission in the insect host. Interestingly, ISFs are commonly found infecting important arbovirus vectors such as the mosquito Aedes aegypti. Cell-fusing...

Honey bees (Apis mellifera) produce an enormous economic value through their pollination activities and play a central role in the biodiversity of entire ecosystems. Recent efforts have revealed the substantial influence that the gut microbiota exert on bee development, food digestion, and homeostasis in general. In this study, deep sequencing was...

Introductory paragraph Since the emergence of SARS-CoV-2 causing COVID-19, the world is being shaken to its core with numerous hospitalizations and hundreds of thousands of deaths. In search for key targets of effective therapeutics, robust animal models mimicking COVID-19 in humans are urgently needed. Here, we show that productive SARS-CoV-2 infe...

Mosquitoes belonging to the genus Aedes can efficiently transmit many pathogenic arboviruses, placing a great burden on public health worldwide. In addition, they also carry a number of insect specific viruses (ISVs), and it was recently suggested that some of these ISVs might form a stable species-specific "core virome" in mosquito populations. Ho...

There are currently no antivirals available to treat infection with enterovirus A71 (EV-A71) or any other enterovirus. The extensively studied capsid binders select rapidly for drug-resistant variants. We here explore whether the combination of two direct-acting enterovirus inhibitors with a different mechanism of action may delay or prevent resist...