Browsing by Author "Gryseels, Sophie"
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Item Arenavirus dynamics in experimentally and naturally infected rodents(EcoHealth Alliance, 2017-06) Marien, Joachim; Borremans, Benny; Gryseels, Sophie; Broecke, Bram Vanden; Becker-Ziaja, Beate; Makundi, Rhodes; Massawe, Apia; Reijniers, Jonas; Leirs, HerwigInfectious diseases of wildlife are typically studied using data on antibody and pathogen levels. In order to interpret these data, it is necessary to know the course of antibodies and pathogen levels after infection. Such data are typically collected using experimental infection studies in which host individuals are inoculated in the laboratory and sampled over an extended period, but because laboratory conditions are controlled and much less variable than natural conditions, the immune response and pathogen dynamics may differ. Here, we compared Morogoro arenavirus infection patterns between naturally and experimentally infected multimammate mice (Mastomys natalensis). Longitudinal samples were collected during three months of bi-weekly trapping in Morogoro, Tanzania, and antibody titer and viral RNA presence were determined. The time of infection was estimated from these data using a recently developed Bayesian approach, which allowed us to assess whether the natural temporal patterns match the previously observed patterns in the laboratory. A good match was found for 52% of naturally infected individuals, while most of the mismatches can be explained by the presence of chronically infected individuals (35%), maternal antibodies (10%), and an antibody detection limit (25%). These results suggest that while laboratory data are useful for interpreting field samples, there can still be differences due to conditions that were not tested in the laboratory.Item "Gairovirus,anovelarena virusof the widespread Mastomys natalensis: genetically divergent,but ecologically similar to Lassa and Morogoro viruses(ElsevierInc, 2015) Gryseels, Sophie; Rieger, Toni; Oestereich, Lisa; Cuypers, Bart; Borremans, Benny; Makundi, Rhodes; Leirs, Herwig; Günther, Stephan; Goüy de Bellocq, JoëlleDespite itsnearpan-Africanrange,theNatalmultimammatemouse, Mastomysnatalensis, carriesthe human pathogenLassavirusonlyinWestAfrica,whiletheseeminglynon-pathogenicarenaviruses Mopeia, Morogoro,andLunahavebeendetectedinthissemi-commensalrodentinMozambique/ Zimbabwe,TanzaniaandZambia,respectively.Here,wedescribeanovelarenavirusin M. natalensis from Gairo districtofcentralTanzania,forwhichweproposethename “Gairo virus”. Surprisingly,thevirusis not closelyrelatedwithMorogorovirusthatinfects M. natalensis only 90kmsouthofGairo,butclusters phylogeneticallywithMobala-likevirusesthatinfectnon-M. natalensis host speciesinCentralAfrican RepublicandEthiopia.Despitetheevolutionarydistance,Gairovirussharesbasicecologicalfeatures with theother M. natalensis-borne virusesLassaandMorogoro.Ourdatashowthat M. natalensis, carrying distantlyrelatedviruseseveninthesamegeographicalarea,isapotentreservoirhostfora varietyofarenaviruses.Item Presence of Mopeia Virus, an African Arenavirus, Related to Biotope and Individual Rodent Host Characteristics: Implications for Virus Transmission(2011) Borremans, Benny; Leirs, Herwig; Gryseels, Sophie; Gu¨ nther, Stephan; Makundi, Rhodes; de Bellocq, Joe¨ lle Gou¨ yThe East African Mopeia virus (MOPV) is an arenavirus closely related to the highly pathogenic West African Lassa virus, even sharing the same reservoir rodent host Mastomys natalensis. Because MOPV is not known to cause human disease, it offers a unique alternative for studying Lassa virus transmission. We investigated how habitat, population density, and host characteristics are related to MOPV occurrence in M. natalensis populations in Morogoro, Tanzania. In 3 contrasting habitats, 511 M. natalensis individuals were trapped, 12.1% (58/480 tested individuals) of which tested seropositive for antibodies and 8.4% (41/489 tested individuals) for MOPVRNA. Although population densities differ among habitats, density and habitat were not significantly correlated to MOPV-RNA or antibody presence. Antibody presence was not significantly correlated with any host characteristics. In contrast, MOPV-RNA presence was inversely related to weight, age, sexual maturity, and body mass index. The model with body mass index as predictor was the best at predicting infection probability. Thirty-five individuals were exclusively MOPV-RNA positive, 52 were exclusively antibody positive, and 6 were both MOPV-RNA and antibody positive. Interpreting these data using experimental infection results from studies on other arenaviruses, this would mean that these infections were very recent, old, and roughly 1–3 weeks after infection, respectively. The higher RNA prevalence in juveniles implies vertical transmission, or that horizontal transmission occurs mainly in this age group due to lack of immunity, higher susceptibility, and/or higher juvenile contact rates. This study demonstrates the strength of combining information on antibody and RNA presence with host characteristics, and how this information can provide valuable insights into transmission dynamics.