Animal production and health newsletter, No. 52, July 2010

Globalization and climate change have had an unprecedented worldwide impact on emerging and re-emerging animal diseases and zoonoses. Climate change is disrupting natural ecosystems by providing more suitable environments for infectious diseases allowing diseasecausing bacteria, viruses, and fungi to move into new areas where they may harm wild life and domestic species, as well as humans. Diseases that were previously limited only to tropical areas are now spreading to other previously cooler areas, e.g. malaria. Pathogens that were restricted by seasonal weather patterns can invade new areas and find new susceptible species as the climate warms and/or the winters get milder. Insect-borne diseases are now present in temperate areas where the vector insects were non-existent in the past, e.g. trypanosomosis, anaplasmosis, bluetongue. Humans are also at an increased risk from insect-borne diseases such as malaria, dengue, and yellow fever. Warmer temperatures are already enabling insects and microorganisms to invade and reproduce in areas where they once could not due to severely low temperatures and seasonal chills. A small rise in temperatures can produce a 10-fold increase in a mosquito population causing an increase of malaria cases, and hence, malaria is now occurring in several Eastern European countries as well as in the highland areas of countries like Kenya where historically cooler climatic conditions had prevented the breeding of populations of diseasecarrying mosquitoes. Freshwater snails, intermediate hosts for fascioliasis, a disease that affects millions of herbivorous animals and humans can now be observed in areas above 4200 meters above sea level in the highlands of Peru and Bolivia as milder temperatures and altered environment conditions are more favourable to their survival. Important zoonotic diseases such as avian influenza, Lyme disease and Rift Valley fever are also likely to spread. Avian influenza viruses occur naturally in wild birds, though often with no dire consequences, however, a highly pathogenic strain of the disease (subtype H5N1) is currently a major concern because it can affect humans. This is mainly because severe winter conditions and droughts, occasioned by climate change can disrupt the normal migration pathways of wild birds and thereby bring both wild and domestic bird populations into greater contact at remaining water sources. The role of tick vectors in diseases like babesiosis in animals and Lyme disease in humans, and of mosquitoes in the transmission of viruses (Rift Valley fever, Dengue fever, African horse sickness, bluetongue) and parasites (malaria) are well known but the geographical distribution of these diseases is expanding as changes in climate continue. It is now evident that diseases carried by insects and ticks are likely to be affected by environmental changes because these creatures are themselves very sensitive to vegetation type, temperature, humidity etc. However, the degree of expansion of diseases is much more difficult to predict, because disease transmission involves many other factors, and not all will be affected to the same extent by environmental change. Therefore, by using historical disease records, present-day groundbased surveillance, remotely sensed (satellite) and other data, mathematical models are being developed that will describe the past, explain the present, and predict the future of vector-borne infectious diseases. The world needs to act effectively to ensure that the various procedures required to prevent and control emerging and re-emerging diseases are fully enabled and also to develop new techniques for their early, rapid, and accurate diagnosis. The IAEA is assisting Member States through our subprogramme to develop and validate early and rapid diagnostic techniques that are simple to use, inexpensive and can be applied in a 'laboratory limited' environment. Most of this work has been done by the utilization of nuclear and nuclear-related technologies that are adapted to more user friendly non-nuclear applications for implementation at field level. Amongst these technologies are the use of 13/14C, 125I, 3H, 32P, 35S to label protein and nucleic acid molecules for specific and sensitive detection, monitoring, and characterization of harmful pathogens that have made a critical contribution towards the development of e.g. ELISA, PCR, real-time PCR and sequencing. The subprogramme, furthermore, ensures the deployment and widespread use of applicable technologies in countries most at risk from climatically influenced infectious diseases. This technical support and guidance to countries (e.g. which test to use, when and for what purpose, equipment needs, staff training and proficiency, and quality management) played a vital role in building developing countries' capacities during recent outbreaks of avian influenza and Rift Valley Fever. The subprogramme has developed, implemented, and transferred immuno and molecular assays that are rapid, inexpensive and capable of being used to process large numbers of samples to detect infectious disease agents that adversely affect livestock productivity and prevent international trade. Four new CRPs started this year: The use of enzymes and nuclear technologies to improve the utilization of fibrous feeds and reduce greenhouse gas emission from livestock, control of foot-and-mouth disease, the use of irradiated vaccines in the control of infectious transboundary diseases of livestock and genetic variation on the control of resistance to infectious diseases in small ruminants for improving animal productivity. Activities of the past six months include several workshops, training courses, research coordination meetings (RCMs) and consultants meetings