The animal health industry plays a key role in livestock protection as a provider of tools to help prevent, control and manage animal diseases affecting Europe’s farming community. Thanks to these tools (vaccines and medicines) Europe has been successful in managing animal diseases such as salmonella, bluetongue or foot and mouth disease which just years ago posed serious threats to animal health, food safety and public health.
The industry remains acutely aware of future critical challenges however and strives to continue developing advanced solutions that protect both animal and human health. Below you will find links to a number of fact sheets outlining some of the successes experienced thanks to animal health products.
Parasites comprise one of the most successful life forms on planet earth. Every vertebrate and many invertebrates play host to several parasite species and individual animals can harbour thousands or even millions of parasites.
Characteristics
Farm livestock are no exception and they may be plagued by any of the major parasite groups: single-celled organisms like coccidian and trypanosomes; helminths such as roundworms, tapeworms or liver fluke and arthropods such as ticks and lice. Infections can be acquired in a number of ways, but commonly animals can pick up parasites by ingestion while grazing, for example many species of helminths, or by direct contact, for example lice and mange mites.
By definition, parasites have negative effects on their hosts, which can range from mortality, for example in acute fasciolosis in sheep, to subtle behavioural changes and loss of production, for example with roundworms in cattle.
Many parasites are species-specific and only infect one, or a narrow range of hosts and relatively few are zoonotic. Some examples of livestock parasites that can be transferred directly or indirectly to man are cryptosporidia, liver fluke and sarcoptic mange mites (scabies). In addition ticks can act as vectors of infections that can affect animals and man, for example Lyme disease. The ubiquitous presence of parasites in specific environments/geographic areas otherwise well suited may render livestock unfit for food production.
Infections with parasites have a direct impact on animal welfare and animal health, as infections lead to disease. The disease symptoms (i.e. blood loss/anaemia, diarrhoea and open sores in skin) can vary in duration and in severity, from being unnoticed to morbidity and in severe cases to mortality.
The direct economic impacts of parasites come from the lost production of infected animals, ranging from sub-optimal production levels to completely lost production due to mortality. The indirect impacts come from the costs of parasite control that contribute to the costs of food production. These can be exacerbated by parasiticide resistance, which can occur after years of use and which means that veterinarians and farmers have to find alternative – sometimes more expensive – solutions for control.
Even single-celled parasites are more biologically and genetically complex than most bacteria and viruses, hence it is much more difficult to develop effective parasite vaccines. Nonetheless, this has been achieved for a few infections, such as coccidiosis in chickens, lungworms in cattle and tropical ticks in cattle.
In the absence of vaccines and in order to complement good husbandry practices, parasiticides can be used to limit the impact of parasitism in domestic livestock. Modern parasiticides are effective in controlling disease and enhancing productivity; some are broad spectrum and can be used to treat parasites from several different taxa simultaneously, others have a narrow spectrum.
Parasiticides should be used carefully, taking into consideration parasite factors like epidemiology and pathophysiology as well as farm practices, like handling and grazing management. Overall it is important that parasiticides are used in a responsible manner so that optimal benefits are achieved and problems such as resistance are minimised.