Biology subjects

Van Houtte, N.

Publications and source records attributed to Van Houtte, N..

5 recordsLinked to original sources

bioRxiv2025

Microparasite prevalence in Southern giant pouched rats (Cricetomys ansorgei) in Morogoro, Tanzania.

Rodents play a critical role in the transmission of zoonotic pathogens, with environmental changes and increasing human-wildlife interactions further amplifying disease spillover risks. Cricetomys spp., commonly found in both human dwellings and agricultural fields, are frequently hunted for consumption, potentially facilitating pathogen transmission. However, their roles in pathogen transmission and disease ecology remain poorly understood. This study investigated the prevalence of three microparasite genera, i.e., Bartonella, Hepatozoon, and Anaplasma, in Cricetomys spp. from Morogoro, Tanzania. We observed a prevalence of 71.9% for Bartonella, 17.5% for Hepatozoon, and 1.8% for Anaplasma. To our knowledge, this is the first study to investigate Bartonella, Hepatozoon, and Anaplasma in Cricetomys spp. in Tanzania. Furthermore, preliminary results indicate that Bartonella infection prevalence is influenced by habitat type, with a significantly higher prevalence observed in rural areas compared to urban areas. This study underscores the potential role of Cricetomys spp. as important reservoirs of infectious diseases.

ecology↗

bioRxiv2024

Assessing Ebola Virus Circulation in the Tshuapa Province (Democratic Republic of the Congo): A One Health Investigation of Wildlife and Human Interactions

The wildlife reservoir and spillover mechanisms of the Ebola virus remain elusive despite extensive research efforts in endemic areas. This study employed a One Health approach to examine the virus circulation in wildlife and the associated human exposure risks in the Tshuapa province of the Democratic Republic of the Congo. In 2021, we collected 1015 samples from 888 animals, predominantly small mammals, and 380 inhabitants of Inkanamongo village, the site of an Ebola virus disease outbreak in 2014. These samples were screened for evidence of current (RNA) or past (IgG antibodies) Ebola virus infections. We also conducted interviews with 167 individuals in the surrounding districts to assess their interactions with wildlife. While no Ebola virus RNA was detected in the wildlife samples, anti-orthoebolavirus IgG antibodies were found in 13 bats and 38 rodents. Among the human participants, 120 individuals had IgG antibodies against at least one orthoebolavirus antigen, with 12 showing seropositivity for two antigens of the same orthoebolavirus, despite not having a prior Ebola disease diagnosis. Furthermore, over 50% of respondents reported frequent visits to the forest to hunt a variety of wild animals, particularly ungulates and rodents, which could account for occasional viral spillovers. The absence of active Ebola virus circulation in wildlife may reflect seasonal patterns in reservoir ecology, like those observed in bats. Similarly, seasonal human activities, like hunting and foraging, may result in periodic exposure risks. These findings highlight the importance of continuous, multidisciplinary surveillance to monitor changes in seasonal spillover risks.

molecular biology↗

bioRxiv2021

SARS-CoV-2 surveillance in Norway rats (Rattus norvergicus) from Antwerp sewer system, Belgium

BackgroundSARS-CoV-2 human-to-animal transmission can lead to the establishment of novel reservoirs and the evolution of new variants with the potential to start new outbreaks in humans. AimWe tested Norway rats inhabiting the sewer system of Antwerp, Belgium, for the presence of SARS-CoV-2 following a local COVID-19 epidemic peak. In addition, we discuss the use and interpretation of SARS-CoV-2 serological tests on non-human samples. MethodsBetween November and December 2020, Norway rat oral swabs, feces and tissues from the sewer system of Antwerp were collected to be tested by RT-qPCR for the presence of SARS-CoV-2. Serum samples were screened for the presence of anti-SARS-CoV-2 IgG antibodies using a Luminex microsphere immunoassay (MIA). Samples considered positive were then checked for neutralizing antibodies using a conventional viral neutralization test (cVNT). ResultsThe serum of 35 rats was tested by MIA showing 3 potentially positive sera that were later shown to be negative by cVNT. All tissue samples of 39 rats analyzed tested negative for SARS-CoV-2 RNA. ConclusionThis is the first study that evaluates SARS-CoV-2 infection in urban rats. We can conclude that the sample of 39 rats had never been infected with SARS-CoV-2. We show that diagnostic serology tests can give misleading results when applied on non-human samples. SARS-CoV-2 monitoring activities should continue due to the emergence of new variants prone to infect Muridae rodents.

ecology↗

bioRxiv2020

Unravelling the evolutionary relationships of hepaciviruses within and across rodent hosts

Hepatitis C virus (HCV; genus Hepacivirus) represents a major public health problem, infecting about 3 % of the human population ({+/-} 185,000,000 people). Because no plausible animal reservoir carrying closely related hepaciviruses has been identified, the zoonotic origins of HCV still remain elusive. Motivated by recent findings of divergent hepaciviruses in rodents and a plausible African origin of HCV genotypes, we have screened a comprehensive collection of small mammals samples from seven sub-Saharan African countries. Out of 4,303 samples screened, 80 were found positive for the presence of hepaciviruses in 29 different host species. We here report 56 novel genomes that considerably increase the diversity of three divergent rodent hepacivirus lineages, which previously were almost exclusively represented by New World and European hepaciviruses. Further-more, we provide undisputable evidence for hepacivirus co-infections in rodents, which remarkably, we exclusively but repeatedly found in four sampled species of brush-furred mice. We also point at hepacivirus co-infections indirectly in different animal hosts by demonstrating evidence for recombination within specific host lineages. Our study considerably expands the available hepacivirus genomic data and elucidates the relatively deep evolutionary history that these pathogens have in rodents compared to other mammalian hosts. Overall, our results emphasize the importance of rodents as a potential hepacivirus reservoir and as models for investigating HCV infection dynamics.

evolutionary biology↗

bioRxiv2020

Evaluation of a pan-Leishmania SL-RNA qPCR assay for parasite detection in laboratory-reared and field-collected sand flies and reservoir hosts.

BackgroundIn eco-epidemiological studies, Leishmania detection in vectors and reservoirs is frequently accomplished by high-throughput and sensitive molecular methods that target minicircle kinetoplast DNA (kDNA). A pan-Leishmania SYBR Green quantitative PCR (qPCR) assay which specifically detects the conserved spliced-leader RNA (SL-RNA) sequence has recently been developed. This study comparatively assessed the SL-RNA assay performance for the detection of Leishmania in field and laboratory infected sand flies and in tissue samples from hyraxes as reservoir hosts. Principal findingsThe qPCRs targeting SL-RNA and kDNA performed equally well on infected sand fly samples, despite preservation and extraction under presumed unfavorable conditions for downstream RNA detection. Nucleic acid extraction by a crude extraction buffer combined with a precipitation step was highly compatible with downstream SL-RNA and kDNA detection. Copy numbers of kDNA were found to be identical in culture-derived parasites and promastigotes isolated from sand fly midguts. SL-RNA levels were approximately 3-fold lower in sand fly promastigotes ({Delta}Ct 1.7). The theoretical limit of detection and quantification of the SL-RNA qPCR respectively reached down to 10-3 and 10 parasite equivalents. SL-RNA detection in stored hyrax samples was less efficient with some false negative assay results, most likely due to the long-term tissue storage in absence of RNA stabilizing reagents. ConclusionThis study shows that a crude extraction method in combination with the SL-RNA qPCR assay is suitable for the detection and quantification of Leishmania in sand flies. The assay provides complementary information to the standard kDNA assays, since it is pan-Leishmania specific and detects viable parasites, a prerequisite for identification of vectors and reservoirs. Author summaryIn order to identify vectors and reservoirs of Leishmania, a large number of sand fly and animal tissue samples needs to be screened, because the infection prevalence is generally low. Hence, sensitive low-cost methods are required for nucleic acid isolation and Leishmania detection. Most approaches amplify DNA targets, in particular minicircle kinetoplast DNA (kDNA). Recently, a qPCR was developed that detects the spliced-leader RNA (SL-RNA) sequence, which is conserved among various Leishmania species and allows detection of viable parasites. We show that the SL-RNA qPCR is highly compatible with a low-cost, crude extraction approach and performs equally well on laboratory and field infected sand fly samples as kDNA qPCR assays. The assay can detect 10-3 parasite equivalent in sand flies and enables Leishmania quantification down to 10 parasites. We found that the copy number of SL-RNA is 3-fold lower in sand fly derived promastigotes compared to cultured promastigotes. SL-RNA detection in hyrax tissue samples appeared less efficient, which is presumably due to long-term storage without RNA stabilizing reagents. Overall, our assay is complementary to kDNA assays as it can identify viable Leishmania stages, which provides pivotal information for identification of reservoirs and vectors and their transmission capacity.

microbiology↗