Ordinarily harmless microbes are being blamed for the recent mass deaths of between 120,000 and 200,000 antelope in recent months, but the exact reason why these bacteria suddenly became virulent has scientists puzzled, according to recently-published media reports.
At one point, more than 60,000 of a critically endangered type of antelope known as saigas were killed by the bacteria in Kazakhstan over a four-day span, Live Science explained. Those saigas were all part of a single herd, the website said, and as veterinarians and conservationists worked to help those antelope, they heard reports similar population crashes all over the countries.
Geoecologist Steffen Zuther, international coordinator of the Altyn Dala Conservation Initiative, told Live Science “at first we were not really alarmed” since there had been limited die-offs over the past few years – but that changed when more and more of the creatures started to succumb to the pathogens. The “extent” and “speed” of the diet off is “unheard of,” he said.
According to the Daily Mail, scientists believe that the bacteria, which normally live harmlessly in the animals’ bodies, have wiped up as much as 80 percent of the saiga antelope populations in Kazakhstan in a matter of weeks. Tissue samples taken from the carcasses of the creatures show that the microbes somehow caused extensive bleeding in many of their organs.
Deaths too fast for disease-causing strains of the bacteria
Specifically, necropsies of the antelopes found that toxins produced by Pasteurella and possibly Clostridia bacteria caused the bleeding. Pasteurella, Live Science said, is normally found in the bodies of ruminants such as the saigas and is normally harmless to the creatures. Furthermore, a genetic analysis of the microbes revealed that they had not mutated significantly.
As Zuther said, “There is nothing so special about it. The question is why it developed so rapidly and spread to all the animals.” The bacteria should not have causes diseases in the animals unless they had weakened immune systems, experts said, and if there was a disease-causing strain of the microbe spreading through the herds, the deaths would not have happened so quickly.
“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 saigas and other mammals,” Carlyn Samuel of the Saiga Conservation Alliance told the Daily Mail on Friday.
“Another opportunistic super-infection with the bacteria Clostridium perfringens was also identified in some cases – perhaps a 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,” she added. “However, it is not clear what triggered these bacteria suddenly to become virulent.”
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Image credit: Wikimedia Commons
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