CCHF is disease that is usually transmitted by contact with blood of infected animals, usually farm animals, or ticks. As such, most people infected work in agriculture or butchering and tanning. In rare cases, CCHF transmission has been observed to occur in hospital settings, such as through the use of contaminated instruments or contact with infectious blood. There appears to be an outbreak in Pakistan and Afghanistan, although at the moment its not clear how the cases are related, if at all. 7 cases were reported in Helmand Province, Afghanistan in June 2010. Several others have been reported in Pakistan since March and there are several cases of “undiagnosed illnesses” in the area which may be CCHF. Initial cases were reported in the expected populations: a butcher, a tanner and other agriculture workers. However the disease appears to be spreading rapidly in hospitals too. 8 individuals at a hospital in Islamabad tested positive for the virus. A doctor in Abbottabad who died of the disease may have spread it to his brother.
It seems like many of these cases are the result of human-to-human transmission rather than tick bites or from contact with animals. The reason for prevalence of this unusual transmission pattern in this particular outbreak is not known yet.