A known or endemic disease is considered to be re-emerging if it shifts its geographical setting, expands its host range, or significantly increases its prevalence.
According to the OIE, of the nearly 1,500 diseases recognised in humans, approximately 60% are due to pathogens that can pass from one species to another and can cause ill-effects in one or both (i.e. multi-host pathogens). In other words, they can live in humans as well as in animals. These diseases that are transmissible between animals and humans are called zoonoses and affect both animal and human health.
Vector-borne diseases are infectious agents such as viruses, bacteria and parasites that living creatures carry and pass on to other living creatures and they are among the most complex of all infectious diseases to prevent and control. Not only is it difficult to predict the habits of mosquitoes, ticks and fleas, but most vector-borne viruses or bacteria infect animals as well as people. Disease carriers, called “vectors,” are usually mosquitoes, ticks and mammals. For example, mosquitoes carry the infectious agents that cause malaria and West Nile virus. Other vector-borne diseases include Lyme disease, avian influenza and rabies.
Ensuring the health of animals is vital to ensuring the health of humans but with man and animal living in ever closer proximity, infections are passing more frequently between them. 75% of emerging human infections originate from animals. They include ebola, Severe Acute Respiratory Syndrome (SARS) and avian influenza, for example. Once present in human populations, the rapid flow of commodities and people across the world enables these pathogens to spread quicker than ever before.
Emerging and re-emerging animal diseases have in recent years been associated with outbreaks that have serious consequences for animal and human health. In order to mitigate the risks, more robust surveillance and control measures need to be put in place, particularly in parts of the developing world where veterinary services and infrastructure is limited or under-resourced.
Preventive veterinary medicines and the widespread use and development of vaccines will play an increasingly important role globally in effective disease control. The animal health industry is actively working with governments and regulators around the world to try to overcome the many challenges still existing to ensure that veterinary medicines can be delivered quickly and effectively when needed.