Dr. Roy Baron, an epidemiologist at the Centers for Disease Control, the Federal agency responsible for analyzing patterns of mysterious death that might point to a potential source of epidemic, acknowledged that nightmares were a possibility but emphasized that no conclusion had been reached.
It is likely that the environment is the source of epidemic strains.
Report-based surveillance systems have become another crucial source of epidemic surveillance to fill this gap.
Smallpox, for centuries a source of epidemic mortality (Terweil, 1987), was targeted by an intensive vaccination campaign.
In fact, event-based informal surveillance now represents a critical source of epidemic intelligence almost all major outbreaks investigated by the World Health Organization (WHO) are first identified through these informal sources (9, 13 ).
One could also argue that Southwood Smith was far from the first person to identify putrefying animal and vegetable matter as a source of epidemic disease and that it was common for eighteenth-century observers to regard dung heaps, human excrement, or other such forms of filth as potentially pestilential.
The solution to this problem has important applications such as locating the sources of epidemics, the sources of news/rumors in social networks, or the sources of online computer virus.
The more humans trigger ecological changes, the greater the likelihood that we will come into contact with direct sources of epidemics.
For instance, data about the transmission of ZIKV in South American wildlife are critical to inform on maintenance of the virus in the region, as sylvatic hosts can serve as a source of recurring epidemics and impede efforts for long-term disease prevention5.
All of these findings suggested a wild reservoir as a potential source of the epidemics, although the researchers could not identify a particular species as the specific source.
