1 National Travel Health Network and Centre (NaTHNaC), UCLH NHS Foundation Trust, 3rd Floor Central, 250 Euston Road, London NW1 2PG, UK.
2 National Travel Health Network and Centre (NaTHNaC), UCLH NHS Foundation Trust, 3rd Floor Central, 250 Euston Road, London NW1 2PG, UK. Electronic address: [email protected].