A new version of this entry is available:
Loading...
Doctoral Thesis
2024
Taeniidae in Namibian wildlife with emphasis on lion, cheetah, and African wild dog
Taeniidae in Namibian wildlife with emphasis on lion, cheetah, and African wild dog
Abstract (English)
An opportunic survey for Echinococcus spp. in wild mammals was conducted in seven distinct stuy areas
throughout Namibia, representing all major ecosystems, between 2012 and 2021. In total, 184 individually
attributable faeces and 40 intestines were collected from eight species of carnivores, and 300 carcasses or organs
of thirteen species of ungulates were examined for Echinococcus cysts. Nested PCR and sequencing of the
mitochondrial nad1 gene led to the identification of five species of the Echinococcus granulosus sensu lato complex.
Echinococcus canadensis G6/7 was found throughout Namibia at low frequency in lions, cheetahs, African wild
dogs, black-backed jackals and oryx antelopes. Echinococcus equinus was present only in northern Namibia,
locally at high frequency in lions, black-backed jackals and plains zebras. Echinococcus felidis was found only in
one small area in the north-east of Namibia, but with high frequency in lions and warthogs. Echinococcus
granulosus sensu stricto was identified only in two African wild dogs in the north-east of Namibia, and Echinococcus
ortleppi occurred in central and southern Namibia in black-backed jackals and oryx antelopes. The
development of fertile cysts indicated active intermediate host roles of oryx antelopes for E. canadensis and
E. ortleppi, of warthogs for E. felidis, and of plains zebras for E. equinus. Our data support earlier hypotheses of
exclusive or predominant wildlife life-cycles for E. felidis involving lions and warthogs, and – in Namibia – for
E. equinus involving lions and/or black-backed jackals and plains zebras. Our data further support an interlink of
wild and domestic transmission for E. ortleppi. A possible involvement of livestock and domestic dogs in transmission
of E. canadensis G6/7 and E. granulosus s.s., the two parasite species with highest zoonotic potential, is
uncertain for Namibia and needs further investigation.
The present study was conducted in the isolated desert town of Oranjemund in the far south of
Namibia. It is an extremely arid region where no livestock husbandry is practiced and only animals
adapted to the desert can be found. However, in and around the city, artifi cial irrigation maintains
lush green patches of grass that attract wild animals, in particular oryx antelopes (Oryx gazella). In
2015 four oryx antelopes were euthanised due to poor conditions and a post-mortem examination
was conducted. Two were found positive for cystic echinococcosis and 16 cysts were collected
for molecular analyses. In addition, faecal samples from black-backed jackals (n=5) and domestic
dogs (n=9), which were regularly observed to feed on oryx carcasses, were collected and taeniid
eggs isolated. Parasite species identifi cation of the cysts and eggs was done by amplifying and se-
quencing the mitochondrial nad1 gene. Both oryx antelopes were found infected with E. ortleppi and
one co-infected with E. canadensis G6/7. Both Echinococcus species were able to develop fertile
cysts in oryx, making oryx antelopes competent hosts for these parasites. Therefore, the analysis of
faecal samples was of high interest and although the numbers were quite small, taeniid eggs were
found in three out of fi ve faecal samples of jackals and in all nine dog samples. However, species
determination was only successful with two jackal and one dog sample. All three were positive for
E. canadensis G6/7. The absence of E. ortleppi may be due to the low number of faecal samples
examined. In our small study, we discovered a rather unique lifecycle of Echinococcus spp. between
jackals and domestic dogs as defi nitive hosts and oryx antelopes as intermediate hosts. Here, the
presence of E. canadensis G6/7 is of particular concern, as it is the second most important causative
agent of CE in humans.
File is subject to an embargo until
This is a new version of:
Notes
Publication license
Publication series
Published in
Faculty
Faculty of Natural Sciences
Institute
Institute of Biology
Examination date
2024-07-17
Supervisor
Edition / version
Citation
DOI
ISSN
ISBN
Language
English
Publisher
Publisher place
Classification (DDC)
570 Biology
Collections
Original object
Free keywords
Standardized keywords (GND)
BibTeX
@phdthesis{Hans Karl Ortwin Aschenborn2024-07-17,
url = {https://hohpublica.uni-hohenheim.de/handle/123456789/16155},
author = {Hans Karl Ortwin Aschenborn},
title = {Taeniidae in Namibian wildlife with emphasis on lion, cheetah, and African wild dog},
year = {2024-07-17},
}