Mass die-off of saiga examined in Kazakhstan

A critical disease workshop has been held in Kazakhstan’s capital Astana, hosted by the Forestry and Hunting Committee of the Republic of Kazakhstan to examine the cause of two separate mass die-offs of the Critically Endangered saiga antelope and the depleting population of the species.

Saiga have experienced one of the fastest declines recorded for mammals in recent decades, with a 95% reduction in population in the past 20 years. The workshop is an excellent example of international cooperation on meeting the challenges of saiga conservation, and has provided an interesting outcome for the conservation and science worlds.

Professor Richard Kock of the Royal Veterinary College, London, has concluded that the primary cause of the mortality of saigas in 2010-2011 in western Kazakhstan was not, as was previously believed, caused by pasteurellosis per se, but was rather due to overeating of moisture laden grass by the animals.

Saiga, post calving are hungry and thirsty and this led to the animals selecting out rich grass pasture, after heavy rain. The engorgement likely led to the dysfunction of the saiga’s digestive tract, which in turn, caused excessive gas bloat in the majority of animals and secondarily affected the lungs, and the animals were dying from asphyxia. Those surviving may then, have succumbed to secondary bacterial infections, which explains the earlier diagnosis of pasteurellosis and latter evidence for clostridiosis.

saiga herd near watering place (Anna Lushchekina)

Scientists have not found any evidence of poisoning or contamination of the pasture grass. Professor Kock explained, “I am not convinced after examining the evidence that the cause for the mass die-off was pasteurellosis or any other primary bacterial or viral transmissible contagious disease for that matter.”

Professor Kock continued, “The epidemiology does not fit well. I suspect this is a die-off associated with pasture factors associated with the specific location where these deaths occurred and the conditions at the time. (They died each year, in the same location and at the same time of year over a very few days. This is no coincidence and untypical of a contagious disease). The climate and pasture condition perhaps resulting in a rapidly progressive digestive disturbance and probable rumen dysfunction with associated problems including, lung pathology, and bloat.”

In May 2010, about 12,000 saigas, mainly females and offspring, were found dead. The dead saigas were found on a 4,500 hectare area in the region’s Zhanibek district, a territory considered one of the main habitats of the Ural population of this animal. The area includes low lying depressions where hay is cut regularly due to the richness of the pasture and grass abundance.

In May 2011, a similar saiga die-off involving a total of about 450 animals was observed in the same site of the 2010 mass mortality whilst the rest of the 4000 or so saiga, which were pasturing elsewhere after calving, remained healthy and unaffected.

Gulmira Izimbergenova, project manager with Fauna & Flora International’s local partner the Association for the Conservation of Biodiversity of Kazakhstan (ACBK) remarked, “This research that has come of out of this workshop is imperative to our understanding of the mass mortality of the saiga. The outcome is crucial in enabling us to plan to conserve this critically endangered antelope.”

For Michael Brombacher, Head of Europe Department at Frankfurt Zoological Society (FZS) the outcome is a major breakthrough for the conservation of this vulnerable species: “The government of Kazakhstan and the international partners invest a lot of money to successfully improve the conservation status of saigas, through the mass die-offs in 2010 and 2011 we lost several thousand animals within days. Now we know what the cause was and can plan prevention to better protect saigas”.

Once migrating in herds up to 100,000 strong across the plains of Central Asia and Russia, the species is now separated into 5 sub-populations and listed by IUCN as critically endangered. The already critical situation became even more severe when the Ural population in western Kazakhstan experienced a mass die off of over 12,000 saiga antelopes found dead in May 2010 within little more than a week. The dead include over 7,750 females who had recently given birth, and 4,250 calves.

International support to Kazakhstan was provided at the explicit request of the Forestry and Hunting Committee of the Republic of Kazakhstan. Professor Richard Kock is funded by the Morris Animal Foundation/ Betty White Wildlife Rapid Response Fund, and the disease workshop is funded by the Frankfurt Zoological Society (FZS), ACBK and the Convention for Migratory Species (CMS). Support has been provided in the framework of FFI’s Ustyurt Landscape Conservation Initiative funded by the USAID SCAPES – Sustainable Conservation Approaches for Priority EcoSystems Programme.