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Development of rapid field diagnostics for identification, control and management of haemorrhagic fever outbreaks

Final Report Summary - VHF DIAGNOSTICS (Development of rapid field diagnostics for identification, control and management of haemorrhagic fever outbreaks)

This project aimed at developing and validating diagnostic tools for early viral haemorrhagic fever outbreak detection and control. A frontline Line-assay (LA) carrying antigens of all African haemorrhagic fever viruses (VHF) was developed and validated for widespread use in local hospitals. This assay is easy to use and the results are easy to interpret. It is also cheap to produce and has a long shelf life. This tool will help to improve outbreak detection in Africa. To develop LA, purified recombinant proteins are expressed in the in vitro RTS-500 system (Roche) and sprayed onto immunoblot strips in the manner of a barcode. The LA is designed to cover all VHF circulating in Africa. Validation of the LA is to be achieved by using available sera in the consortium of laboratories, centralised in a repository for VHF diagnostics development.

The project included a long-term field trial in local hospitals. A mobile integrated fluorescent PCR (F-RT-PCR) for outbreak investigation teams was also developed. It consisted of a panel of F-RT-PCRs covering all haemorrhagic fever viruses, a robust simple nucleic acid extraction protocol and ready to use lyophilised PCR mixes. This tool will help outbreak investigation teams to improve their ability to manage and control haemorrhagic fever outbreaks. Specifically, existing and newly developed (CCHFV, RVF, YFV, EBOZV, EBOSV, MBGV, and LASV) F-RT-PCRs assays are validated for field use. To assess the sensitivity of each assay, RNA-standards for each aetiological agent derived from sections of the respective genomes are used. The specificity of the assays are evaluated with recent isolates of each aetiological agent and patient and / or rodent samples provided by the collaborating laboratories. The extraction of nucleic acids from blood samples is to be adapted to field conditions. Ready to use lyophilised PCR mixes are tested for each aetiological agent to allow field PCR without the need for refrigeration facilities.

The team expects to develop an integrated toolbox for mobile outbreak investigation teams which will enable them to perform initial differential diagnostics and to follow up patients during the containment of the outbreak This will contain of a field evaluated set of lyophylised PCR mixes for VHF plus FluA and B virus detection in combination with a field evaluated simple extraction protocol. If successful it may be possible to produce the LA assay for the African market.

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