Person-to person transmission has not been reported in persons whose contact with an infected patient occurred during the incubation period. However, contact with blood and other body fluids of infected humans especially during the later stages of illness which are characterised by vomiting or haemorrhage could spread the infection. Airborne transmission during work with virus cultures or laboratory samples containing the virus was also reported among laboratory workers. Inoculation through broken skin or wound could be another means of transmission.