Category: Hippos, Lions | Date: Apr 28 2008 | By: William

On April 15th we reported that two lions had died within the Mara Triangle. Here is an annotated version of the findings from the investigation, the original written by Brian Heath CEO & Dr Asuka Takita:

The history of the case reveals that three out of four affected lions had fed on a hippo carcass found on the river bank on March 31st. The first signs of sickness appeared three days post-ingestion, when a sick lion (Male #1) was found to be weak, staggering and sitting under a thicket.

The following morning, Male #1 was unable to walk and showed clear signs of front limb paralysis; where the animal could not stand and walk in a normal posture. He used his hind limbs to “hop like a rabbit” in an attempt to move forward.

3.4.08 Paralysis sets in.

The condition deteriorated rapidly within the course of a day, and Male #1 was no longer able to ‘hop’ by the early afternoon. On the same day, another young male (Male #2) from the same pride began showing a more severe form of paralysis and was recumbent by afternoon. This was followed by a lesser degree of paralysis in two more males during the next five days.

The first paralysed lion was euthanised by a KWS vet for post-mortem and sample collection. The post-mortem did not reveal significant pathological changes suggestive of infectious disease, and all of the organs looked normal except for slightly hyperaemic small intestinal mucosa.

The brain sample was submitted to Kabete Vet Labs for rabies testing, in which the results came out negative. Tissue samples (liver, kidney, small intestine) together with stomach contents, were submitted to Government Chemist Toxicology Lab to test for possible poisoning. The results showed that the stomach contents revealed a high concentration of Carbofuran. The stomach content of a second hippo found dead on 13.4.08 subsequently tested positive for Carbofuran.

Hippo found dead on 13.4.08

An environmental survey was undertaken by Mara Conservancy staff from habitats in the vicinity of both lions and hippos. Water and soil samples were taken from the area, including water samples collected from a tributary where another dead hippo was found. All of the water samples tested negative for insecticides, while some of the soil samples showed traces of Carbofuran.

Based on a history collected from rangers, clinical signs manifested by all four affected lions, post-mortem findings and toxicology results, the paralysed lions are suspected to have suffered from secondary poisoning. It would appear that the hippos died as a direct result from ingesting Carbofuran contaminated plants, and that lions were then affected by feeding on the hippo carcass. It is believed that the severity of paralysis could be correlated with the amount of contaminated hippo meat consumed by each lion.

Due to feline susceptibility to chemical toxicosis, similarity in the mechanism and action of Carbamates and Organophosphates, the tendency of some Carbamates to initiate delayed neuropathy through NTE inhibition, and the absence of other alternative explanations identified for the paralysis, it is believed that Carbofuran-induced neuropathy can occur in animals.

7.4.08 Tests being done on sick lion by KWS.

The Mara Conservancy recommend an immediate ban of the use of potentially toxic chemicals (insecticides, pesticides, acaricides, molluscicide, especially Carbofuran and Organophosphates) inside conservation areas.

Based on the findings and the location of the affected animals, there is no reason to suspect the involvement of the local communities surrounding the Mara Triangle.

Thank you to everyone for both your support and your patience since our report of the lions deaths on 15th April. We ask new visitors to our website to click here to find out more about our Urgent Appeal, and also ask you to consider making a donation to help maintain basic park operations during this time of financial difficulty. Thank you.

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