Share thisA public health emergency declared due to the newly emerged “swine flu” virus (H1N1) was recently classified as a worldwide pandemic. This is definitely an indication of impending similar, serious “brewing storms”. Since 1998, public health officials and scientists have been speculating about this with the avian flu (H5N1) virus strain. Fortunately, this has not evolved yet and may never do so. But, make no mistake; we are on the precipice of unpleasant health and health care threats that need to be addressed.
These influenza events, plus the fact that approximately 75% of recently emerging infectious diseases affecting humans are diseases of animal origin, strongly suggest the need for a paradigm change on how public health approaches these phenomena called “zoonotic diseases”, i.e. diseases transmissible from animals to man.
Today, many institutional, geographic, and financial barriers often prohibit meaningful interactions among experts. The result is that surveillance, research, prevention, and control measures for cross-species infections like influenza and dangerous bacteria emerging from antibiotic resistance, like those demonstrated by methicillin-resistant Staphylococcus aureus (MRSA) between pigs and people, have been short changed. This deficit must be rectified in order to pursue an enlightened course of modern health and health care for this generation and for generations to come. The 1918-1919 influenza pandemic killed 50 to 100 million people worldwide. Emerging influenza viruses have been isolated from a variety of animals, including humans, pigs, horses, wild and domestic birds, and sea mammals. The recent events caused by swine flu came to light only when human cases occurred. The interval between cross-species spread and the declaration of a public health emergency was extremely brief, a matter of days. It is reasonable to ask: could surveillance for the emergence of new strains of flu be more effective if targeted at animals—the “mixing pot” of flu virus evolution? Could we develop more effective tools to identify strains with potential to spill over from animals to humans?
Besides influenza, other animal diseases are transmissible to humans. Hantaviruses exist in various rodent reservoirs where the hosts are persistently infected without disease symptoms. Specific hantaviruses transmitted from the contaminated urine and feces of infected rodents cause two important human diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus-pulmonary syndrome (HPS). Nipah virus is a newly discovered virus of fruit bats responsible for encephalitis outbreaks in southeast Asia. West Nile, a virus of birds, invaded the U.S. in 1999 and is now endemic. Emerging bacterial disease agents can be transmitted by food animals including E. coli 0157:H7, various Salmonella species, Campylobacter species, and Streptococcus iniae (from farmed fish). Leptospirosis is the most common rat-transmitted disease in the United States.