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"Lebreton, Matthew"
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Reorganization and expansion of the nidoviral family Arteriviridae
by
LeBreton, Matthew
,
Rogers, Jeffrey
,
O’Connor, David H
in
Arteriviridae - classification
,
Arteriviridae - genetics
,
Arteriviridae - isolation & purification
2016
The family Arteriviridae presently includes a single genus Arterivirus. This genus includes four species as the taxonomic homes for equine arteritis virus (EAV), lactate dehydrogenase-elevating virus (LDV), porcine respiratory and reproductive syndrome virus (PRRSV), and simian hemorrhagic fever virus (SHFV), respectively. A revision of this classification is urgently needed to accommodate the recent description of eleven highly divergent simian arteriviruses in diverse African nonhuman primates, one novel arterivirus in an African forest giant pouched rat, and a novel arterivirus in common brushtails in New Zealand. In addition, the current arterivirus nomenclature is not in accordance with the most recent version of the International Code of Virus Classification and Nomenclature. Here we outline an updated, amended, and improved arterivirus taxonomy based on current data. Taxon-specific sequence cut-offs are established relying on a newly established open reading frame 1b phylogeny and pairwise sequence comparison (PASC) of coding-complete arterivirus genomes. As a result, the current genus Arterivirus is replaced by five genera: Equartevirus (for EAV), Rodartevirus (LDV + PRRSV), Simartevirus (SHFV + simian arteriviruses), Nesartevirus (for the arterivirus from forest giant pouched rats), and Dipartevirus (common brushtail arterivirus). The current species Porcine reproductive and respiratory syndrome virus is divided into two species to accommodate the clear divergence of the European and American “types” of PRRSV, both of which now receive virus status. The current species Simian hemorrhagic fever virus is divided into nine species to accommodate the twelve known simian arteriviruses. Non-Latinized binomial species names are introduced to replace all current species names to clearly differentiate them from virus names, which remain largely unchanged.
Journal Article
The global distribution of tetrapods reveals a need for targeted reptile conservation
2017
The distributions of amphibians, birds and mammals have underpinned global and local conservation priorities, and have been fundamental to our understanding of the determinants of global biodiversity. In contrast, the global distributions of reptiles, representing a third of terrestrial vertebrate diversity, have been unavailable. This prevented the incorporation of reptiles into conservation planning and biased our understanding of the underlying processes governing global vertebrate biodiversity. Here, we present and analyse the global distribution of 10,064 reptile species (99% of extant terrestrial species). We show that richness patterns of the other three tetrapod classes are good spatial surrogates for species richness of all reptiles combined and of snakes, but characterize diversity patterns of lizards and turtles poorly. Hotspots of total and endemic lizard richness overlap very little with those of other taxa. Moreover, existing protected areas, sites of biodiversity significance and global conservation schemes represent birds and mammals better than reptiles. We show that additional conservation actions are needed to effectively protect reptiles, particularly lizards and turtles. Adding reptile knowledge to a global complementarity conservation priority scheme identifies many locations that consequently become important. Notably, investing resources in some of the world’s arid, grassland and savannah habitats might be necessary to represent all terrestrial vertebrates efficiently.
The global distribution of nearly all extant reptile species reveals richness patterns that differ spatially from that of other taxa. Conservation prioritization should specifically consider reptile distributions, particularly lizards and turtles.
Journal Article
Antimicrobial resistance from a one health perspective in Cameroon: a systematic review and meta-analysis
by
Wade, Abel
,
LeBreton, Matthew
,
Akoachere, Jane-Francis Tatah Kihla
in
Animal
,
Antimicrobial resistance
,
Bacteria
2019
Background
Antimicrobial resistance (AMR) is widely acknowledged as a global health problem, yet in many parts of the world its magnitude is not well elucidated. A baseline assessment of the AMR prevalence is a priority for implementation of laboratory-based AMR surveillance This review, focused on a One health approach, aimed at describing the current status of AMR in Cameroon.
Methods
PubMed, Google Scholar and African Journals Online databases were searched for articles published in English and French in accordance with the PRISMA guidelines. Retrieval and screening of article was done using a structured search string with strict inclusion/exclusion criteria. Free-text and grey literature were obtained by contacting the authors directly. The pooled prevalence and 95% confidence intervals were calculated for each pathogen–antibiotic pairs using random-effects models.
Result
Amongst 97 full-text articles reviewed, 66 met the eligibility criteria. The studies originated from the Centre (24; 36.4%), South-West (16; 24.2%), West (13; 19.7%), Littoral (9; 13.6%) and other (4; 6.1%) regions of Cameroon. These studies reported AMR in human (45; 68.2%), animals (9; 13.6%) and the environment (12; 18.2%). Overall, 19 species of bacteria were tested against 48 antibiotics. These organisms were resistant to all classes of antibiotics and showed high levels of multidrug resistance.
Escherichia coli, Klebsiella pneumoniae
and
Staphylococcus spp
were reported in 23, 19 and 18 of the human studies and revealed multidrug resistance (MDR) rates of 47.1% [95% CI (37.3–57.2%)], 51.0% [95% CI (42.0–59.9)] and 45.2% [95% CI (38.0–54.7)], respectively.
Salmonella spp
was reported in 6 of the animal studies and showed a MDR rate of 46.2% [95% CI (39.2–53.5%)] while
Staphylococcus spp
in 8 of environment studies showed MDR rate of 67.1% [95% CI (55.2–77.2%)].
Conclusion
This review shows that resistance to commonly prescribed antibiotics in Cameroon is high. The findings emphasize the urgent need to address gaps in the standardization of AMR diagnostics, reporting and use of available information to optimize treatment guidelines for the arsenal of antibiotics. Effective AMR surveillance through continued data sharing, large-scale collaboration, and coordination of all stakeholders is essential to understand and manage the AMR national burden.
Journal Article
Climate change induced complex shifts in snake distributions expose people to snakebite and threaten biodiversity
by
Chirio, Laurent
,
LeBreton, Matthew
,
Kanankege, Kaushi S. T.
in
Animal Distribution
,
Animals
,
Biodiversity
2026
Snakes play pivotal roles in many ecosystems. While some species, including medically important ones, are considered threatened by the IUCN, snakebite takes a heavy toll on rural agricultural populations in the developing world. Approximately 138,000 deaths and 400,000 disabilities result from snakebite annually and WHO has pledged to reduce the resulting health burden by 50% by 2030. Among a plethora of reasons for insufficient snakebite mitigation, one is limited explicit knowledge of how, where, and when humans and snakes interact, which limits the timely, accurate, and efficient deployment of resources. Here, we revise the list of medically important snakes based on recent taxonomic updates and use high-resolution data from a broad range of published and unpublished resources to compare expert-derived ranges with statistical geographical models of habitat suitability for all 508 most medically important snake species globally. Our study is the first to model every single medically important snake species including data deficient ones, at the highest resolution to date, and with the largest supporting occurrence dataset. We generate geographically explicit estimates of how much human and snake populations overlap (snake-human-overlap-index; SHOI), which is the most fundamental prerequisite for human-snake conflict to occur. Finally, we model the effects of climate change on snake distributions. We predict substantial, short- and long-term shifts in snake distributions, including range contractions for many threatened species and increased human exposure to species of major public health concern. In combination with other drivers of increased snake-human conflict, such as human behaviours and snake traits, our predictions can be used to decide where to stockpile which antivenom, how to ensure adequate capacity of individual health facilities, how to improve health care accessibility of remote at-risk communities, and where to focus conservation efforts for threatened snake species. Hence, we highlight the need for geographically targeted efforts to benefit both vulnerable human and snake populations, as part of a One-Health strategy.
Journal Article
Ecophysiological variation across a forest-ecotone gradient produces divergent climate change vulnerability within species
by
Matthew Le Breton
,
Adam H. Freedman
,
Timothy C. Bonebrake
in
biogeography
,
Cameroon
,
Climate change
2018
Climate change related risks and impacts on ectotherms will be mediated by habitats and their influence on local thermal environments. While many studies have documented morphological and genetic aspects of niche divergence across habitats, few have examined thermal performance across such gradients and directly linked this variation to contemporary climate change impacts. In this study, we quantified variation in thermal performance across a gradient from forest to gallery forest-savanna mosaic in Cameroon for a skink species (Trachylepis affinis) known to be diverging genetically and morphologically across that habitat gradient. Based on these results, we then applied a mechanistic modelling approach (NicheMapR) to project changes in potential activity, as constrained by thermal performance, in response to climate change. As a complimentary approach, we also compared mechanistic projections with climate-driven changes in habitat suitability based on species distribution models of forest and ecotone skinks. We found that ecotone skinks may benefit from warming and experience increased activity while forest skinks will likely face a drastic decrease in thermal suitability across the forest zone. Species distribution models projected that thermal suitability for forest skinks in coastal forests would decline but in other parts of the forest zone skinks are projected to experience increased thermal suitability. The results here highlight the utility of mechanistic approaches in revealing and understanding patterns of climate change vulnerability which may not be detected with species distribution models alone. This study also emphasizes the importance of intra-specific physiological variation, and habitat-specific thermal performance relationships in particular, in determining warming responses.
Journal Article
Knowledge, attitude and practices of snakebite management amongst health workers in Cameroon: Need for continuous training and capacity building
2018
Snakebite has only recently been recognized as a neglected tropical disease by the WHO. Knowledge regarding snakebites and its care is poor both at the population level, and at the health care staff level. The goal of this study was to describe the level of knowledge and clinical practice regarding snakebite among health care staff from Cameroon.
A two-day training dedicated to snakebite and its care was organized in 2015 in Yaoundé, capital city of Cameroon. A total of 98 health care staff from all over Cameroon attended the training. Prior to and after the training, an evaluation quantified the attendees' level of knowledge. Pre- and post-training evaluations were compared to assess knowledge improvement.
Overall, prior to the training knowledge regarding snakebite and care was poor, and wrong beliefs that \"pierre noire\" or tourniquet were useful in case of snakebite were common. Knowledge was statistically improved after the training.
Trainings dedicated to all type of health care staff towards snakebite to improve care are needed, this training must take into consideration the context and the targeted population.
Journal Article
Serological and molecular analysis of henipavirus infections in synanthropic fruit bat and rodent populations in the Centre and North regions of Cameroon (2018–2020)
2025
Background
Bats and rodents have been identified as reservoirs for several highly pathogenic and zoonotic viruses including henipaviruses, a genus within the
Paramyxoviridae
family. A number of studies have revealed the circulation of henipaviruses at the wildlife-human-livestock interface in Cameroon. In this study, we describe the molecular analysis as well as the development and evaluation of a Bead-based Multiplex Binding Assay (BMBA) using an in-house Indirect Enzyme Linked Immunosorbent Assay (ELISA) to confirm the detection of henipavirus infection in wildlife species.
Results
A total of 600 fruit bats and 600 rodents were sampled between March 2018 and June 2020. Samples were analyzed using a semi-nested RT-PCR assay followed by sequencing of the PCR fragments. Transudates (754) were screened for the presence of henipavirus-specific antibodies in a BMBA and confirmed by ELISA using Hendra virus (HeV), Nipah virus (NiV) and Ghana virus (GhV) glycoproteins expressed in
Leishmania tarentolae
, and commercially available HeV G and NiV G glycoproteins.
Henipavirus-specific antibodies were detected in 19/531 (3.6%) bat transudates screened by BMBA and confirmed by ELISA. Seroprevalence rates in the Centre and North Regions were 12/291 (4.1%) and 7/240 (2.9%) respectively. All rodents and shrews were serologically negative. Henipavirus RNA sequences were not detected in any of the samples screened in this work.
Conclusion
This study provides further data supporting the circulation of Henipaviruses in fruit bats (
Eidolon helvum
) which are roosting and reproducing in proximity to human and livestock populations in the Centre and North Regions of Cameroon. This also establishes the first detection of Henipavirus specific antibodies in
Eidolon helvum
populations in the North Region of Cameroon.
Journal Article
origin of malignant malaria
by
Boesch, Christophe
,
LeBreton, Matthew
,
Djoko, Cyrille F
in
Amino Acid Sequence
,
ancestry
,
Animals
2009
Plasmodium falciparum, the causative agent of malignant malaria, is among the most severe human infectious diseases. The closest known relative of P. falciparum is a chimpanzee parasite, Plasmodium reichenowi, of which one single isolate was previously known. The co-speciation hypothesis suggests that both parasites evolved separately from a common ancestor over the last 5-7 million years, in parallel with the divergence of their hosts, the hominin and chimpanzee lineages. Genetic analysis of eight new isolates of P. reichenowi, from wild and wild-born captive chimpanzees in Cameroon and Côte d'Ivoire, shows that P. reichenowi is a geographically widespread and genetically diverse chimpanzee parasite. The genetic lineage comprising the totality of global P. falciparum is fully included within the much broader genetic diversity of P. reichenowi. This finding is inconsistent with the co-speciation hypothesis. Phylogenetic analysis indicates that all extant P. falciparum populations originated from P. reichenowi, likely by a single host transfer, which may have occurred as early as 2-3 million years ago, or as recently as 10,000 years ago. The evolutionary history of this relationship may be explained by two critical genetic mutations. First, inactivation of the CMAH gene in the human lineage rendered human ancestors unable to generate the sialic acid Neu5Gc from its precursor Neu5Ac, and likely made humans resistant to P. reichenowi. More recently, mutations in the dominant invasion receptor EBA 175 in the P. falciparum lineage provided the parasite with preference for the overabundant Neu5Ac precursor, accounting for its extreme human pathogenicity.
Journal Article
Targeted genomic sequencing with probe capture for discovery and surveillance of coronaviruses in bats
by
LeBreton, Matthew
,
Atibu Losoma, Joseph
,
Ngay Lukusa, Ipos
in
Animals
,
Chiroptera
,
Coronaviridae
2022
Public health emergencies like SARS, MERS, and COVID-19 have prioritized surveillance of zoonotic coronaviruses, resulting in extensive genomic characterization of coronavirus diversity in bats. Sequencing viral genomes directly from animal specimens remains a laboratory challenge, however, and most bat coronaviruses have been characterized solely by PCR amplification of small regions from the best-conserved gene. This has resulted in limited phylogenetic resolution and left viral genetic factors relevant to threat assessment undescribed. In this study, we evaluated whether a technique called hybridization probe capture can achieve more extensive genome recovery from surveillance specimens. Using a custom panel of 20,000 probes, we captured and sequenced coronavirus genomic material in 21 swab specimens collected from bats in the Democratic Republic of the Congo. For 15 of these specimens, probe capture recovered more genome sequence than had been previously generated with standard amplicon sequencing protocols, providing a median 6.1-fold improvement (ranging up to 69.1-fold). Probe capture data also identified five novel alpha- and betacoronaviruses in these specimens, and their full genomes were recovered with additional deep sequencing. Based on these experiences, we discuss how probe capture could be effectively operationalized alongside other sequencing technologies for high-throughput, genomics-based discovery and surveillance of bat coronaviruses.
Journal Article
Emergence of Unique Primate T-Lymphotropic Viruses among Central African Bushmeat Hunters
by
Wolfe, Nathan D.
,
LeBreton, Matthew
,
Mpoudi-Ngole, Eitel
in
Base Sequence
,
Biological Sciences
,
Blotting, Western
2005
The human T-lymphotropic viruses (HTLVs) types 1 and 2 originated independently and are related to distinct lineages of simian T-lymphotropic viruses (STLV-1 and STLV-2, respectively). These facts, along with the finding that HTLV-1 diversity appears to have resulted from multiple cross-species transmissions of STLV-1, suggest that contact between humans and infected nonhuman primates (NHPs) may result in HTLV emergence. We investigated the diversity of HTLV among central Africans reporting contact with NHP blood and body fluids through hunting, butchering, and keeping primate pets. We show that this population is infected with a wide variety of HTLVs, including two previously unknown retroviruses: HTLV-4 is a member of a phylogenetic lineage that is distinct from all known HTLVs and STLVs; HTLV-3 falls within the phylogenetic diversity of STLV-3, a group not previously seen in humans. We also document human infection with multiple STLV-1-like viruses. These results demonstrate greater HTLV diversity than previously recognized and suggest that NHP exposure contributes to HTLV emergence. Our discovery of unique and divergent HTLVs has implications for HTLV diagnosis, blood screening, and potential disease development in infected persons. The findings also indicate that cross-species transmission is not the rate-limiting step in pandemic retrovirus emergence and suggest that it may be possible to predict and prevent disease emergence by surveillance of populations exposed to animal reservoirs and interventions to decrease risk factors, such as primate hunting.
Journal Article