In December, we reported that a first-ever outbreak of Ebola-Reston in swine was identified on farms 25 miles north of Philippines capital of Manila. While the virus has been reported in Philippine monkeys and has been previously transmitted to human handlers, Ebola-Reston is of far less concern than the other incurable, and high-fatality Ebola strains.
But on Jan. 23, Philippine Health Secretary Francisco Duque reported that one of the swine workers from infected farms has now tested positive to the disease. This is another first, and is raising an alarming note of concern to the outbreak. While Duque told a news conference there was little immediate health risk, others see a red flag.
Hong Kong infectious disease expert Lo Wing-lok has reported that "viruses jumping across species is always worrying. If it continues to do so, the virus will adapt to the human body or may mutate to become more transmissable among humans."
There are a few aspects to this public health concern. First is that pigs are farmed for meat, whereas monkeys are not -- the majority of exported Philippine primates serve as laboratory animals. The farm worker who has tested positive for the virus opens the door to a new mode of species jump, with Lo saying this virus "may get magnified in swine and we could get a higher-density virus in the environment and more cases of human infection can (then) occur." (Ebola isn't the only virus Lo is keeping a wary eye on -- he's warning of the possibility of a "terrible" outbreak of bird flu on the Chinese mainland, although his warning is contingent on further tests on dead birds washing ashore in Hong Kong.
The other issue experts are considering is the impact of viral mutation, which may not only facilitate a human-to-human transmission of the virus, but create a virus with symptoms of more severe illness.