Tsavo Mobile Veterinary Unit - November 2009

The Unit was called to assist in the surveillance of Rift Valley Fever (RVF) disease in wildlife in Ijara district in North-Eastern Province

The Unit was called to assist in the surveillance of Rift Valley Fever (RVF) disease in wildlife in Ijara district in North-Eastern Province. The Kenya Wildlife Service (KWS) has partnered with other institutions that are offering a multi-disciplinary approach to establish an integrated platform to monitor emerging infectious diseases caused by the Arboviruses. These diseases include Rift Valley Fever (RVF), Yellow Fever and Dengue Fever amongst other diseases of socio- economic importance. Initially, the project is focused on RVF in a 3 year program funded by Google.org under the Arbovirus Incidence and Diversity (AVID) project.

RVF is associated with periodic localized outbreaks but it is not known how the virus is sustained between epidemics. The AVID project aims at understanding the dynamics of the disease and other Arboviruses that will improve the ability to manage the disease while simultaneously establishing a platform applicable to other pathogens. It will involve molecular diagnostics to determine the circulation of Arboviruses among human, livestock, wildlife and the arthropod vectors.

The role of KWS in the project is to sample wildlife in the three areas identified for the study that are Ijara, Naivasha and Baringo districts. These are areas where epidemics have occurred previously. Ijara and Baringo were selected based on the outbreaks of 2006-07 while Naivasha is a known RVF endemic area. A total of 63 animals comprising of 58 warthogs and 5 gerenuks were sampled between the 2nd and 12th of September at 3 sites in Ijara district that had previously been identified to be the study areas.  The exercise was planned to coincide with the surveillance in humans and livestock as well as the collection of the vectors by the other institutions in the study.

Animals were captured physically by driving them into an erected net system where they would get entangled. They would then be disentangled and restrained by at least two people to facilitate sampling. After capture, the animals would be observed for any signs of disease and general health status. They were all ascertained to be healthy. Blood was collected aseptically from the milk vein (subcutaneous abdominal vein) in the warthogs and from the jugular vein in the gerenuks into two plain and one EDTA tubes. Serum was extracted by centrifugation after at least 6 hours of standing to allow for clot formation. At least four aliquots of serum and EDTA blood were prepared, labeled properly and preserved frozen in liquid nitrogen. Remaining clots after the harvesting of the serum were preserved with 70% ethanol at room temperature. Ticks were collected from different parts of the body and also preserved in liquid nitrogen. The animal’s age, sex and species were noted and recorded.

Another activity during the month was the treatment of Seraa, a seven years old elephant rehabilitated and released two years ago into the wild. The elephant had two arrow wounds on the chest area. One of the injuries was quiet deep and the arrow seemed to have been thrown at close range and at high velocity for it had caused some damage on one rib. Two bone fragments were retrieved from the injury. After a lot of probing the wound and ascertaining that the arrow head was not lodged inside, the animal was given a good prognosis. The other injury was not serious. A high dose of systemic antibiotics were given, the wounds topically treated and the animal revived.

At the time of writing this report, the animal had made very good progress. Both wounds were healing nicely and any further treatment considered not necessary.

An adult female zebra with a tight snare that inflicted an extensive injury round the neck was also treated at the pipeline area in Tsavo East. Despite the seriousness of the injury, the animal had a good prognosis because the vital structures in the neck were intact. The animal was in good body condition.

Another case was that of Ol Malo in the elephant stockades at Ithumba in Northern Tsavo East. The 7 years old elephant released back to the wild after several years of rehabilitation was reported to have an abscess at the ventral abdomen that required the Unit’s attention. Abscesses in elephants may have serious consequences if not treated early as they may spread beneath and undermine the skin rather than rupturing externally. Infection may spread extensively under the skin resulting in necrotizing fasciitis, sepsis and death. However, examination revealed an umbilical hernia rather than an abscess. These are not uncommon in elephants especially in very young ones where they may result from a congenital defect in the muscles of the abdomen resulting in an abnormal protrusion of abdominal contents through the defect. Treatment is surgical to close the opening. This would be successful in very young elephants but not at Ol Malo's age for serious complications such as suture dehiscence and infection can arise with serious consequences. It is believed that Ol Malo who had been lost for many months without appearing at the stockades sustained some trauma on the umbilical area resulting to a weak spot or rupture of the muscles that permitted intestines to bulge through it. The hernia contents could be pushed back into the abdomen. It will be observed closely for progress.

The last activity in November was a visit to Amboseli national park on the 25th November to assess the drought situation following increased mortalities of herbivores particularly the wildebeests, zebras and buffaloes. Despite the rest of the country receiving rains since October, Amboseli has received insignificant amounts and mortalities had continued to be recorded until about two weeks ago. Incidentally, areas around the park have received good amounts of rainfall that has eluded the park. Many wildebeests and zebras have consequently migrated from the park in search of forage elsewhere. This has eased off grazing pressure on the grass. This coupled by the little rains that have been experienced over the past two weeks has seen the grass start to regenerate. An assessment by a team comprising of KWS and external researchers in Amboseli was determined to be sufficient to sustain the few remaining animals in the park until the rains come. A pilot feeding program for herbivores proposed by stakeholders in the Amboseli ecosystem was suspended until a latter date should the rains fail completely.

Report by Dr. David Ndeereh

The Mobile Veterinary Unit operated by The David Sheldrick Wildlife Trust working with The Kenyah Wildlife Service and funded by Vier Pfoten.