Recent outbreaks of Avian Flu and Swine Flu have raised public awareness of the ability of pathogens to cross from the environment to humans. Avian Flu and Swine Flu are viruses but many other pathogens also have an environmental source, including microbes and fungi. The pathogens do not necessarily need to be new in order to cross over; there may be existing diseases for which the connection between animal- and human health has yet to be recognized. In order to help develop effective treatments and preventative strategies in humans it is useful to study the source and routes of transmission of these pathogens from the environment to man.
Researchers at CEH are investigating the links between birds and the pathogens that they carry. Recent work has identified a fungus associated with seabirds that can cause fatal systemic disease in humans with compromised immune systems. Other research by CEH is looking at a possible connection between Johne’s disease in animals and Crohn’s disease in humans. Johne’s disease is caused by a bacterium that affects the small intestine of mainly ruminants (cattle, sheep) but also primates. Crohn’s disease also occurs in the gastrointestinal tract, has similarities to Johne’s disease and is now significantly associated with the Johne’s disease pathogen. Recent evidence across the world suggests that there is a five-fold increase per decade in the incidence Crohn’s disease particularly in children. CEH is carrying out environmental studies on the sources of the bacterium and investigating the possible exposure routes to humans (through air, rain runoff into rivers, and milk).
Results of this research and the evidence obtained will help policy-makers determine the action needed to reduce environmental exposure routes and ultimately lower instances of Crohn’s disease in humans.