|Tawny Frogmouth Parasitic Disease Alert|
| Issued by Taronga Zoo July 2004|
A parasitic disease affecting the central nervous system of wild tawny frogmouths has emerged around Sydney NSW since early March 2004. The main signs at first are weakness and the inability of affected birds to perch, flap their wings or fly. Eventually the birds cannot right themselves when placed on their backs. the birds usually remain alert and often willingly accept food. Affected birds usually show no signs of trauna and some appear well nourished. The disease is usually progressive and potentially fatal. Currently there is no satisfactory treatment available for tawny frogmouths.
The parasite causing this disease in tawny frogmouths is Angiostrongylus cantonensis, a nematode worm that normally harbours in the lungs and brains of wild rats. These rat parasites require slugs and snails as intermediate hosts before they can become infectious for the birds. When tawny frogmouths eat infected slugs and snails, the larvaue then migrate to their spinal cords and brains causing the clinical disease described above.
Angiostrongylus cantonensis has also occurred in other wildlife species including flying foxes, possums and macropods, as well as in domestic animals and sometimes humans. Hosts other than the rat are considered as accidental hosts, and can only contract the disease by ingesting the infectious larval forms in infected slugs and snails.
Between December 2000 and May 2002, two cases of A. cantonensis were diagnosed in tawny frogmouths in the Sydney area by the Australian Registry of Wildlife Health at Taronga Zoo. Between March and May 2004 eight more cases were identified, mostly from the northern suburb areas of Cremorne, Mosman, Warringah and Lane Cove. this is a significant increase. The cluster of cases may represent an increase in the prevalence of A. cantonensis in tawny frogmouths in the wider Sydney area, and the disease needs to be further monitored.
In Australia, the occurrence of A. cantonensis in Queensland has been well known but the geographic shift into hosts in New South Wales appears to be on the increase. Risk factors that could influence the infection rate in tawny frogmouths for A. cantonensis may be the availability and ease of birds finding and consuming infected slugs and snails.
The purpose of this communication is to alert the bird / tawny frogmouth co-ordinators of the wildlife groups in the greater Sydney area to consider this parasitic disease in rehab tawny frogmouths that do not appear to recover from concussion or other traumatic events. Coordinators can then direct information to the Australian Registry of Wildlife Health who will continue to monitor these cases.
The Australian Registry of Wildlife Health
Phone (02) 9978 4749