Balding Disease Killing Wombats
- Thread starter Chlidonias
- Start date
devilfish
Well-Known Member
More information is now available. An email from a research veterinary pathologist at the University of Adelaide has been forwarded by the ISID (International Society for Infectious Diseases) to everyone on their mailing list (ProMED-mail). It's a highly scientific document, but a good read for anyone with an interest in pathology. I've cut out parts, but the main body of the email is below:
We believe this disease in Murraylands Southern Hairy Nosed wombats is
multifactorial and largely due to severe chronic nutritional stress in
these animals. In the areas in which affected wombats are found, very
few native grasses and regular feed sources remain, and the habitat is
dominated by _Carrichtera annua_, _Asophodelus fistulosus_, _Marrubium
vulgare_, and _Heliotropium europaeum_.
In some juvenile wombats examined, we have found poor body condition,
extensive bilaterally symmetrical dorsal and lateral alopecia,
jaundice, and severe haemorrhagic and exudative dermatitis of sun
exposed areas (dorsal thorax and abdomen, rump, and dorsal head,
particularly ears and periocular skin) with sparing of the ventral and
inner legs.
Microscopically, skin lesions are characterised by severe superficial
dermal neutrophilic vasculitis, superficial dermal thrombosis and
haemorrhage, and ischaemic necrosis of the epidermis and superficial
dermis. There is significant pigmentary incontinence in skin from
these animals, perhaps rendering them more susceptible to
photosensitisation.
Liver lesions in these animals were characterised by severe periportal
to bridging fibrosis, bile ductile proliferation, megalocytosis,
anisocytosis and anisokaryosis, and there was histological evidence of
secondary bacterial hepatitis.
Differential diagnoses included pyrollizidine alkaloid toxicoses,
aflatoxicosis, and other plant toxins. Liver lesions were submitted to
the Joint Pathology Centre (previously Armed Forces Institute of
Pathology) in Washington for a 2nd opinion, who subsequently reported
the same histopathological findings and differential agents.
Of the PA containing plants found in the region from where affected
wombats have been found, only _Heliotropium europium_ was found to be
present. We have subsequently had these plant specimens confirmed as
_Heliotropium europaeum_ by the South Australian Herbarium. We are
also collaborating with toxicologists from the University of
Queensland, who are presently examining plant samples as well as
wombat stomach, liver and faecal samples for toxic alkaloids.
Investigations are ongoing.
Importantly, not all wombats with alopecia have been found to have
liver lesions. We are concerned for chronic nutritional stress as a
cause for alopecia (as also suggested by David Thomson), as many skin
lesions are non-inflammatory and appear more typical of metabolic or
hormonal disruptions to hair growth cycles. We are also finding other
problems not consistent with hepatotoxicity alone. Hormonal
disturbances and other toxicities have not yet been excluded and
remain in the differential diagnoses. Investigations are continuing
and will be published in the near future. We have not found any
evidence for sarcoptic mange in the animals examined so far.
We believe this disease in Murraylands Southern Hairy Nosed wombats is
multifactorial and largely due to severe chronic nutritional stress in
these animals. In the areas in which affected wombats are found, very
few native grasses and regular feed sources remain, and the habitat is
dominated by _Carrichtera annua_, _Asophodelus fistulosus_, _Marrubium
vulgare_, and _Heliotropium europaeum_.
In some juvenile wombats examined, we have found poor body condition,
extensive bilaterally symmetrical dorsal and lateral alopecia,
jaundice, and severe haemorrhagic and exudative dermatitis of sun
exposed areas (dorsal thorax and abdomen, rump, and dorsal head,
particularly ears and periocular skin) with sparing of the ventral and
inner legs.
Microscopically, skin lesions are characterised by severe superficial
dermal neutrophilic vasculitis, superficial dermal thrombosis and
haemorrhage, and ischaemic necrosis of the epidermis and superficial
dermis. There is significant pigmentary incontinence in skin from
these animals, perhaps rendering them more susceptible to
photosensitisation.
Liver lesions in these animals were characterised by severe periportal
to bridging fibrosis, bile ductile proliferation, megalocytosis,
anisocytosis and anisokaryosis, and there was histological evidence of
secondary bacterial hepatitis.
Differential diagnoses included pyrollizidine alkaloid toxicoses,
aflatoxicosis, and other plant toxins. Liver lesions were submitted to
the Joint Pathology Centre (previously Armed Forces Institute of
Pathology) in Washington for a 2nd opinion, who subsequently reported
the same histopathological findings and differential agents.
Of the PA containing plants found in the region from where affected
wombats have been found, only _Heliotropium europium_ was found to be
present. We have subsequently had these plant specimens confirmed as
_Heliotropium europaeum_ by the South Australian Herbarium. We are
also collaborating with toxicologists from the University of
Queensland, who are presently examining plant samples as well as
wombat stomach, liver and faecal samples for toxic alkaloids.
Investigations are ongoing.
Importantly, not all wombats with alopecia have been found to have
liver lesions. We are concerned for chronic nutritional stress as a
cause for alopecia (as also suggested by David Thomson), as many skin
lesions are non-inflammatory and appear more typical of metabolic or
hormonal disruptions to hair growth cycles. We are also finding other
problems not consistent with hepatotoxicity alone. Hormonal
disturbances and other toxicities have not yet been excluded and
remain in the differential diagnoses. Investigations are continuing
and will be published in the near future. We have not found any
evidence for sarcoptic mange in the animals examined so far.