Looking back on 2006, there were a lot of big headlines in health, science, and politics—all the topics I like to write (and whine) about.
H5N1 certainly wasn’t our only “sudden killer” viral concern in 2006. One thing that kept bubbling to the surface of my news stream this year was the many instances of viral hemorrhagic fevers all over the world. Ebola (Zaire) decimated the wild gorilla population in West Africa to possible extinction levels; Crimean-Congo hemorrhagic fever (a tickborne disease) was seen in South Africa, Iran, Pakistan, Russia, and Turkey; Rift Valley fever, a zoonosis associated with livestock, killed 11 people of 12 confirmed cases in Kenya — a number which could rise dramatically as thousands of (possibly infected) animals will be slaughtered for the Eid holiday; an unidentified hemorrhagic fever with renal syndrome, probably associated with rodents was noted in Russia; and finally, we saw a particularly large number of dengue fever and dengue hemorrhagic fever cases this year throughout Asia, the Middle East, and South America. Dengue fever virus exists in four varieties, or serotypes. On first infection, it’s generally just an awful experience but survivable—dengue is known as breakbone fever due to the excruciating joint pain it causes. On second infection with a different serotype, however, the victim risks developing hemorrhagic symptoms resulting in death. As dengue continues to spread through the global population, expanding with climatic conditions favoring its mosquito hosts, more and more people will become susceptible to developing the hemorrhagic form of dengue, including those living in the southern U.S. and frequent travelers to dengue-endemic areas.
While last year it was reported that three species of fruit bats were the natural reservoir of the Ebola virus, further research this year raises questions by showing that the association of Ebola with fruit bats can only be traced back a few years. Is the original reservoir yet to be found? In other research, a vaccine for Ebola was shown safe in human trials, and a Marburg hemorrhagic fever vaccine was tested successfully in monkeys.
Emerging viruses, including not only the hemorrhagic fevers but other deadly pathogens such as Nipah virus, will continue to grow in the future as humans invade and develop more land, grow and intermingle larger populations of susceptible livestock, and experience further global climate change. While numerous research programs are investigating the emergence and spread of such viruses, it is a fact that we do not move as quickly as they do. In the case of H5N1, already endemic in various populations of wild waterfowl, we can’t make a decisive move (development of a targeted vaccine) until the virus does it first by mutating into the form that readily infects and transmits between humans. Or can we? A few reports of investigations into universal influenza targets could pan out into either a vaccine or treatment effective against any flu virus, not just one with specific properties. Let’s hope that does pan out before 2007 turns out to be the year 80 million people succumb to a single mutation.