Update on the Saiga Antelope Tragedy in Kazakhstan< Back
Between 9th May and 3rd June this year, large herds of saiga antelope at calving sites in the central population in Kazakhstan died suddenly. 148,800* carcasses were counted at burial sites by Government rangers. Our latest expedition to the migration area and die-off sites** reported many carcasses remained unburied and so the figure might be higher. However, scientists did observe live animals, mostly males and surviving young saiga. Fortunately, neither of the two other populations in Kazakhstan, nor those in Mongolia and Russia, were affected.
The most likely primary disease appears to be haemolytic septicaemia, caused by an opportunistic infection with the bacterium Pasteurella multocida serotype B, which is naturally found as a latent infection in the upper respiratory tract of saiga antelope and other mammals. Another opportunistic super-infection with the bacteria Clostridium perfringens was also identified in some cases (perhaps half) and this infection results in the release of massive amounts of lethal toxins into the intestine, which are absorbed into the bloodstream and contribute to a rapid death. However, it is not clear what triggered these bacteria suddenly to become virulent.
The potential triggers of the outbreak are still to be determined, and are key to developing any long term strategy to prevent or control these outbreaks. Triggers in domestic livestock can include sudden temperature changes associated with heavy rain and could include other stresses related to internal and/or external environmental factors including climate, pasture conditions and other infections. Field and laboratory studies are ongoing to further clarify this syndrome in the saiga antelope.
The large geographical area over which die-offs occurred suggests that a single environmental contaminant is not particularly plausible, and soil, water and air analyses completed are largely within normal ranges for detectable radiation and known contaminants and pollutants. However toxic algae, plants or otherwise naturally occurring toxins cannot be ruled out at this stage. Analysis of whether records and vegetation will also provide clues as to the potential underlying causes of the outbreak.
Since at least the 1950s, saiga die-offs have been recorded in Kazakhstan. Recent die-offs in 2010 and 2011 prompted a review of current outbreaks and investigation procedures, and the outcome was an annual monitoring and research programme established in 2012, with a focus on the calving period each Spring. This included a new co-operation between Kazakhstani and international scientists. Due to co-operation, saigas at two of the recent die-off locations could be intensively monitored throughout the tragedy, and diagnostic samples could be taken.
An additional expedition was undertaken between June 27th and July 8th to conduct further monitoring of wildlife and livestock as well as environmental sampling of migration routes and die-off sites, including soil, vegetation and water. Samples from this expedition are being processed and will be compared to those from previous and similar outbreaks in other species. We are also planning future expeditions to collect similar data, and the combined results of these investigations will help to support national and international policies for improving responses to any further disease outbreaks.
The research brings together an international interdisciplinary team with expertise in veterinary science, ecology, conservation policy, environmental change and pastoralism, with partners in Kazakhstan, the UK, Sweden, Italy, France and Germany.