Biology subjects

Schrama, M.

Publications and source records attributed to Schrama, M..

3 recordsLinked to original sources

bioRxiv2024

Emergence and Dynamics of Usutu and West Nile Viruses in the Netherlands, 2016-2022

BackgroundMosquito-borne arboviruses, including Usutu virus (USUV) and West Nile virus (WNV), are emerging threats in Europe, with changes in climate, land use, and increased travel and trade influencing their dynamics. Understanding the emergence and establishment of these viruses in new regions is critical for informing targeted mitigation of drivers of emergence and enhancing public and wildlife health preparedness. MethodsSeven years (2016-2022) of interconnected studies were conducted in the Netherlands. Live birds were sampled by volunteer bird ringers, dead birds were referred for sampling by citizen-scientists and zoological institutions, and mosquitoes were trapped. Samples were tested for USUV and WNV using RT-PCR and screened for Orthoflavivirus antibodies using protein microarray and neutralization assays. Sequencing and phylogenetic analyses were performed. FindingsUSUV was first detected in the Netherlands in 2016, caused large outbreaks in birds until 2018, and resurged in 2022. One dominant, enzootic lineage, co-circulated alongside several limited introductions of a second lineage. A localized WNV lineage 2 outbreak occurred in live birds and mosquitoes in 2020, with another positive bird in 2022 and serological evidence of continued circulation. InterpretationWe provide the first comprehensive, multi-year documentation of two emerging arboviruses in the Netherlands. USUV was enzootically maintained over seven years and was associated with substantial bird mortality. WNV is in an early stage of establishment with no bird mortality observed. Our integrated wildlife sampling was crucial in detecting a human WNV outbreak, bringing this emerging threat to public health attention. FundingZonMw, Dutch Research Council (NWO), European Union, Government of the Netherlands

microbiology↗

bioRxiv2021

Agricultural pressures impair trophic link between aquatic microorganisms and invertebrates

Decadal declines in aquatic ecosystem health prompted monitoring efforts and studies on effects of human practices on aquatic biodiversity, yet a consideration of ecological processes and trophic linkages is increasingly required to develop an in-depth understanding of aquatic food webs and its vulnerability to human activities. Here, we test in laboratory incubations using natural organic matter whether agricultural practices have an effect on two interacting ecological processes (i.e., decomposition and invertebrate growth) as the relevant temporal components of the trophic linkage between aquatic microbial communities and aquatic invertebrates. We further assess whether these altered trophic interactions are visible on ecologically relevant scales. We observed clear patterns in agricultural constraints on microbial decomposition, which coincided with reduced invertebrate growth and an unexpected increase in invertebrate consumption of organic matter. Similar differences in invertebrate length depending on land use were observed in our field survey, thereby providing important clues on the relevance and vulnerability of interdependent processes that can serve to improve future forays in monitoring ecosystem health.

ecology↗

bioRxiv2019

A comparative assessment of adult mosquito trapping methods to estimate spatial patterns of abundance and community composition in southern Africa

BackgroundAssessing adult mosquito populations is an important component of disease surveillance programs and ecosystem health assessments. Inference from adult trapping datasets involves comparing populations across space and time, but comparisons based on different trapping methods may be biased if traps have different efficiencies or sample different subsets of the mosquito community.\n\nMethodsWe compared four widely-used trapping methods for adult mosquito data collection in Kruger National Park (KNP), South Africa: Centers for Disease Control miniature light trap (CDC), Biogents Sentinel trap (BG), Biogents gravid Aedes trap (GAT) and a net trap. We quantified how trap choice and sampling effort influence inferences on the regional distribution of mosquito abundance, richness and community composition.\n\nResultsThe CDC and net traps together collected 96% (47% and 49% individually) of the 955 female mosquitoes sampled and 100% (85% and 78% individually) of the 40 species or species complexes identified. The CDC and net trap also identified similar regional patterns of community composition. However, inference on the regional patterns of abundance differed between these traps because mosquito abundance in the net trap was influenced by variation in weather conditions. The BG and GAT traps collected significantly fewer mosquitoes, limiting regional comparisons of abundance and community composition.\n\nConclusionsThis study represents the first systematic assessment of trapping methods in natural savanna ecosystems in southern Africa. We recommend the CDC trap or the net trap for future monitoring and surveillance programs.

ecology↗