publications of the research group systems medicine of
infections([BRICS]SMID)http://hdl.handle.net/10033/6206612024-03-28T18:36:05Z2024-03-28T18:36:05ZHigh-resolution epidemic simulation using within-host infection and contact data.Nguyen, Van KinhMikolajczyk, Rafael THernandez-Vargas, Esteban Abelardohttp://hdl.handle.net/10033/6217542019-08-30T11:32:11Z2018-07-17T00:00:00ZHigh-resolution epidemic simulation using within-host infection and contact data.
Nguyen, Van Kinh; Mikolajczyk, Rafael T; Hernandez-Vargas, Esteban Abelardo
BACKGROUND:
Recent epidemics have entailed global discussions on revamping epidemic control and prevention approaches. A general consensus is that all sources of data should be embraced to improve epidemic preparedness. As a disease transmission is inherently governed by individual-level responses, pathogen dynamics within infected hosts posit high potentials to inform population-level phenomena. We propose a multiscale approach showing that individual dynamics were able to reproduce population-level observations.
METHODS:
Using experimental data, we formulated mathematical models of pathogen infection dynamics from which we simulated mechanistically its transmission parameters. The models were then embedded in our implementation of an age-specific contact network that allows to express individual differences relevant to the transmission processes. This approach is illustrated with an example of Ebola virus (EBOV).
RESULTS:
The results showed that a within-host infection model can reproduce EBOV's transmission parameters obtained from population data. At the same time, population age-structure, contact distribution and patterns can be expressed using network generating algorithm. This framework opens a vast opportunity to investigate individual roles of factors involved in the epidemic processes. Estimating EBOV's reproduction number revealed a heterogeneous pattern among age-groups, prompting cautions on estimates unadjusted for contact pattern. Assessments of mass vaccination strategies showed that vaccination conducted in a time window from five months before to one week after the start of an epidemic appeared to strongly reduce epidemic size. Noticeably, compared to a non-intervention scenario, a low critical vaccination coverage of 33% cannot ensure epidemic extinction but could reduce the number of cases by ten to hundred times as well as lessen the case-fatality rate.
CONCLUSIONS:
Experimental data on the within-host infection have been able to capture upfront key transmission parameters of a pathogen; the applications of this approach will give us more time to prepare for potential epidemics. The population of interest in epidemic assessments could be modelled with an age-specific contact network without exhaustive amount of data. Further assessments and adaptations for different pathogens and scenarios to explore multilevel aspects in infectious diseases epidemics are underway.
2018-07-17T00:00:00ZAn Egyptian HPAI H5N1 isolate from clade 2.2.1.2 is highly pathogenic in an experimentally infected domestic duck breed (Sudani duck).Samir, MHamed, MAbdallah, FKinh Nguyen, VHernandez-Vargas, E ASeehusen, FBaumgärtner, WHussein, AAli, A A HPessler,, Fhttp://hdl.handle.net/10033/6213412019-08-30T11:34:22Z2018-01-24T00:00:00ZAn Egyptian HPAI H5N1 isolate from clade 2.2.1.2 is highly pathogenic in an experimentally infected domestic duck breed (Sudani duck).
Samir, M; Hamed, M; Abdallah, F; Kinh Nguyen, V; Hernandez-Vargas, E A; Seehusen, F; Baumgärtner, W; Hussein, A; Ali, A A H; Pessler,, F
The highly pathogenic avian influenza (HPAI) H5N1 viruses continue to cause major problems in poultry and can, although rarely, cause human infection. Being enzootic in domestic poultry, Egyptian isolates are continuously evolving, and novel clades vary in their pathogenicity in avian hosts. Considering the importance of domestic ducks as natural hosts of HPAI H5N1 viruses and their likelihood of physical contact with other avian hosts and humans, it is of utmost importance to characterize the pathogenicity of newly emerged HPAI strains in the domestic duck. The most recently identified Egyptian clade 2.2.1.2 HPAI H5N1 viruses have been isolated from naturally infected pigeons, turkeys and humans. However, essentially nothing is known about their pathogenicity in domestic ducks. We therefore characterized the pathogenicity of an Egyptian HPAI H5N1 isolate A/chicken/Faquos/amn12/2011 (clade 2.2.1.2) in Sudani duck, a domestic duck breed commonly reared in Egypt. While viral transcription (HA mRNA) was highest in lung, heart and kidney peaking between 40 and 48 hpi, lower levels were detected in brain. Weight loss of infected ducks started at 16 hpi and persisted until 120 hpi. The first severe clinical signs were noted by 32 hpi and peaked in severity at 72 and 96 hpi. Haematological analyses showed a decline in total leucocytes, granulocytes, platelets and granulocyte/lymphocyte ratio, but lymphocytosis. Upon necropsy, lesions were obvious in heart, liver, spleen and pancreas and consisted mainly of necrosis and petechial haemorrhage. Histologically, lungs were the most severely affected organs, whereas brain only showed mild neuronal degeneration and gliosis at 48 hpi despite obvious neurological clinical signs. Taken together, our results provide first evidence that this HPAI H5N1 isolate (clade 2.2.1.2) is highly pathogenic to Sudani ducks and highlight the importance of this breed as potential reservoir and disseminator of HPAI strains from this clade.
2018-01-24T00:00:00ZWindows of opportunity for Ebola virus infection treatment and vaccination.Nguyen, Van KinhHernandez-Vargas, Esteban Ahttp://hdl.handle.net/10033/6210832019-08-30T11:36:33Z2017-08-21T00:00:00ZWindows of opportunity for Ebola virus infection treatment and vaccination.
Nguyen, Van Kinh; Hernandez-Vargas, Esteban A
Ebola virus (EBOV) infection causes a high death toll, killing a high proportion of EBOV-infected patients within 7 days. Comprehensive data on EBOV infection are fragmented, hampering efforts in developing therapeutics and vaccines against EBOV. Under this circumstance, mathematical models become valuable resources to explore potential controlling strategies. In this paper, we employed experimental data of EBOV-infected nonhuman primates (NHPs) to construct a mathematical framework for determining windows of opportunity for treatment and vaccination. Considering a prophylactic vaccine based on recombinant vesicular stomatitis virus expressing the EBOV glycoprotein (rVSV-EBOV), vaccination could be protective if a subject is vaccinated during a period from one week to four months before infection. For the case of a therapeutic vaccine based on monoclonal antibodies (mAbs), a single dose might resolve the invasive EBOV replication even if it was administrated as late as four days after infection. Our mathematical models can be used as building blocks for evaluating therapeutic and vaccine modalities as well as for evaluating public health intervention strategies in outbreaks. Future laboratory experiments will help to validate and refine the estimates of the windows of opportunity proposed here.
2017-08-21T00:00:00ZBatch Cultivation Model for Biopolymer ProductionTorres-Cerna, C. E.Alanis, A. Y.Poblete-Castro, I.Hernandez-Vargas, E. A.http://hdl.handle.net/10033/6209612019-08-30T11:33:01Z2017-04-15T00:00:00ZBatch Cultivation Model for Biopolymer Production
Torres-Cerna, C. E.; Alanis, A. Y.; Poblete-Castro, I.; Hernandez-Vargas, E. A.
2017-04-15T00:00:00Z