It is estimated that more than a 1000 Angolan free-tailed bats (Mops condylurus) died over the third week of July at Letaba Camp in the Kruger National Park (KNP). Sharp-eyed visitors alerted section ranger Joe Nkuna and Amy Pollard, assistant interpretive officer about bats found dead near one of the eight bat houses at the camp on Saturday, July 14.
Joe Nkuna decided to call in disease experts after staff collected another 40 carcasses on Monday and he also found about 150 carcases at the bat house at the ranger station. Dr Dewald Keet, KNP State veterinarian, called in the assistance of the Special Pathogens Unit at the National Institute for Communicable Disease.
While they were on their way, Dewald and researchers, Dr Janusz Paweska, Prof Bob Swanepoel, and Alan Kemp, asked Amy and Liezel van Lingen, a conservation student at Letaba, to collect a few samples which led to the discovery of another 134 carcasses. The linen room staff then showed them their collection of about 500 carcasses they collected earlier that day.
Dr Paweska and his team arrived on Thursday. "We looked for the Angolan free-tailed bats in three places - one of the occupied staff houses, two empty houses (in one of which we stayed) and the bat houses," says Prof Swanepoel. They found many 'very white skeletons' in the ceiling of the house in which they stayed, which implies that there had been deaths in the staff houses prior to the deaths in the bat houses.
Prof Swanepoel says it is not possible at this stage to say what caused the deaths. "The possibilities included poisoning, sudden unusual cold weather or infectious agents: blood parasites, bacteria or viruses." According to Prof Swanepoel the Letaba staff indicated that there was no recent change or large-scale use of insecticide or other chemicals at the camp. Cold weather has also been ruled out.
The team dissected a few bats on site to preserve frozen organ samples for laboratory tests, but could not reach any immediate conclusions. They returned to the Institute with the samples where tests are in progress.
'This could possibly be a new thing and tests could take some time, but we never discard any material so we could always resume tests later if necessary." says Prof Swanepoel. According to Liezel, who has been regularly checking the bat houses for more carcasses, there have been no more bat deaths recorded at Letaba.