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mysteriöses Krokodilsterben

"...So far, 130 crocodile carcasses have been found," said Travers. "Every week we seem to find more when we
fly over the area. The Olifants and Letaba river system has the largest population of Nile crocodiles in the Kruger Park..."

http://www.iol.co.za/index.php?set_id=1 ... 443C512112

UNDIAGNOSED DIE-OFF, CROCODILE - SOUTH AFRICA (03): KRUGER NATIONAL PARK
************************************************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>

Date: Fri 8 Aug 2008
Source: South African National Parks -- Official website; media
release [edited]
<http://www.sanparks.org/parks/kruger/ne ... eaths2.php>


Research on KNP croc deaths continues
-------------------------------------
Kruger National Park (KNP) scientists, researchers, and veterinarians
teamed up with crocodile experts and other ecologists from
universities and other institutions in yet another attempt at trying
to unravel the mystery of the crocodile deaths in the Olifants and
Letaba rivers this week.

Included in the team that conducted the post mortem and capture
operations were crocodile capture expert Hannes Botha from Mpumalanga
Parks and Tourism Agency, Dr Jan Myburgh from Onderstepoort, Prof
Henk Bowman from North-West University (South Africa), and IUCN
[International Union for Conservation of Nature] crocodile expert Dr
Fritz Huchzermeyer.

"Although we learnt a lot during the operation, we have not yet found
the exact cause of the pansteatitis that has caused the deaths of so
many crocodiles in this river system," said the KNP's head of
Scientific Services, Mr Danie Pienaar.

The 3 day, 3 night operation not only saw post mortem operations on a
number of crocodile carcasses found on the banks of the rivers
concerned, but it also included the night capture of 11 live
crocodiles. This is the 1st time that such a large-scale night
capture operation has taken place in the KNP.

"A new theory that is being investigated is that because the live
crocodiles are preying on the carcasses, they are getting infected
from eating affected fat and tissue and thus continue spreading the
disease. In order to break this potential cycle, we have taken the
decision to remove the carcasses from the water and burn all the
carcasses we find," Mr Pienaar added.

So far, 10 crocodile carcasses have been burnt. KNP Veterinary
Surgeons from Veterinary Wildlife Services (VWS) also took the
opportunity to carry out post mortems on 3 of these carcasses, before
they were burnt.

But it was the live capture of crocodiles on the nights of Sunday to
Tuesday (3-5 Aug 2008) that was of considerable interest to all
concerned. A total of 11 specimens were captured. Blood and tissue
biopsy samples were taken from all these reptiles, before they were
tagged with plastic markers and released back into the water.

"Although we didn't manage to capture our goal of 30 crocodiles, the
operation has given us an idea of the rate of infection at the
confluence of the Olifants and Letaba Rivers specifically, with 7 out
of the 11 captured crocodiles showing affected fat on the biopsy
sample.

This high infection rate unfortunately also means that we can still
expect a large number of crocodile deaths in the lower Olifants and
Letaba rivers," Mr Pienaar added.

So far, the results of tests done on the water and crocodile tissue
samples from laboratories both in South Africa and overseas have yet
to give conclusive answers on the reasons why the crocodiles have
been dying.

Presently, KNP rangers and scientists have counted 130 crocodile
carcasses, with more discovered during every survey flight, which are
conducted weekly with a Bantam Ultralight Aircraft.

"However, we can rule out blue-green algae and we can also confirm
that the water in the Olifants River is safe for drinking, which is
certainly good news for tourists to the area, particularly those
staying at Olifants Rest Camp and undertaking any of the activities
in the area, including the Olifants Back Pack Trail and the Olifants
Wilderness Trail," concluded Mr Pienaar.

The river system of the Olifants and Letaba rivers, which includes
the Olifants River Gorge, has the highest Nile crocodile population
densities in the entire KNP.

[Byline: Raymond Travers]

--
Communicated by:
Wolfgang Preiser
Professor and Head
Division of Medical Virology
Department of Pathology, Faculty of Health Sciences
Stellenbosch University and NHLS Tygerberg
PO Box 19063, Tygerberg 7505
South Africa
<preiser@sun.ac.za>
<http://www.sun.ac.za/virology>


[Although in the media release above the etiology of the crocodile
mortality is apparently attributed to "infection," no supportive
evidence is presented. Laboratory results are anticipated with
interest. - Mod.AS

Photo of Nile crocodile (_Crocodylus niloticus_):
<http://upload.wikimedia.org/wikipedia/c ... codile.jpg>
- Mod.JW

Kruger National Park in northeastern South Africa is the largest game
reserve in the country. It can be located on the map, which also shows
the Olifants River, at
<http://www.safarinow.com/destinations/k ... k/map.aspx>. -
CopyEd.MJ]

Life and death for holy S Africa crocs
06.12.2008 - BBC

Scientists in South Africa are trying to find out why so many crocodiles are dying in the rivers around Kruger Park, to the north of Johannesburg, where more than 50 of the reptiles have been found washed up on river banks in Limpopo Province ... mehr

Gruß
Birgitt