den appearance of S. rrachea in at least 3 widely separate localilies suggests that it is now widespread in the white-backed magpie population in southern Victoria, but the reason for its sudden appearance is unknown. S. frachea is a cosmopolitan parasite of a wide variety of birds (Keymer 1Y69) and so it is likely that a variety of other Australian wild birds, particularly insectivores, may be infected. S. trachea is a significant parasite of domestic poultry and game birds (Wehr 1971), heavy infections causing severe respiratory distress and death, particularly in juvenile birds. Cage and aviary birds may become infected by contamination of their environments with the faeces of wild birds. Pens and ranges used for rearing domestic poultry and game birds may be similarly contaminated, though wild birds are not thought 10 be important in the spread of infection t o commercial flocks in North America (Wehr 1972). The life cycle of S. trachea is direct, infective larvae developing within the egg under suitable environmental conditions. Birds are infected by eating eggs containing the infective third stage larvae. Earthworms and other invertebrates may act as transport hosts. Often birds are more easily infected by feeding them such infected transport hosts than by feeding them eggs containing the infective larvae (Wehr 1972). Infected birds may be treated with thiabendazole in the feed using 0.05% to 0.5% for 4 to 14 days (Wehr 1972) or may be treated orally at 40 mg/kg for 10 days (Altman 1977). Cooper (1972) recommended 0.5 g/kg body weight for birds of prey but suggested that the treatment should be repeated. Continuous feeding of thiabendazole at 0.1% of the ration is successful in preventing the disease in pheasants but is probably not economic (Wehr 1972). Fenbendazole given in the feed at 60 ppm was effective in eliminating S. trachea eggs from the faeces of wild birds (Enigk and Dey-Hazra 1976). Hygiene, sanitation and maintenance of dry conditions will minimise larval development and survival and aid control. Rotation of rearing areas and dilution of accumulated infec-

tions by cultivation or grazing may aid control in environments such as pens used for pheasani rearing. In appropriate aviaries, exclusion of transport hosts may aid control. Exclusion of wild birds from aviaries and prevention of faecal contamination of aviaries by them will aid in minimising the introduction of the oarasite. K. E. HARRIGAN, J . H. ARUNDEL, Veterinary Clinical Centre Werribee, Victoria 3030 14 April 1978

References Altman. R. B. (1977)-ln Current Veterinary Therapy V f Small Animal Practice, Ed. R. W . Kirk, W. B. Saunders Co., Philadelphia, p 686. Cooper, J . E. (1972)-Veterinary Aspects of Captive Birds of Prey, Appendix IV. Drugs Used for Treatment of Birds of Prey. The Hawk Trust, Newent, Gloucestershire. Enigk, K. and Dey-Hazra, A. (1976)--/ientierPraxis21: 133. Keymer, I. F. (1969)-1n Diseases of Cage and Aviary Birds, Ed. M. L. Petrak, Lea and Febiger, Philadelphia, p 409. McLennan. G . C. (19.3)-Aust. vet. J . 0: 227. Wehr, E. E. (1971)--In Infectious and Parasitic Diseases of Wild Birds, Ed. J . W. Davis, R. C. Anderson, L. Karstad and D. 0. Trainer, Iowa State University Press, Ames, Iowa. p 193. Wehr, E. E. (1972)-1n Diseases of Poultry, 6th edn, Ed. M. S. Hofstad, B. W. Calnek, C. F. Helmboldt, W. M . Ried and H. W. Yoder, Iowa State University Press, Ames, Iowa, p 849.

A SPECIES OF LUNGWORM IN A DOG IN WESTERN AUSTRALIA Three Metastrongyloid nematodes, all in the genus Filaroides are known to be parasitic in canine lung tissue. Filaroides osleri, described originally by Osler (1879) is the most widespread, and reaches adulthood in the vicinity of the tracheo-bronchial bifurcation. The other two, F. milksi (Whitlock 1956) and F. hirfhi,(Georgi and Anderson 1975) are both found in the pulmonary parenchyma. Neither Fmilksi, nor F.hirthi has been reported from outside the United States of America, but F.osleri is widespread and especially prevalent in feral canids, although with only a sporadic prevalence in domestic dogs. Another metastrongyloid Angiostrongylus \'asorurn is found in the pulmonary arteries of dogs and there is some evidence that this parasite may occur in Australia (Seddon 1967). The first confirmed case of F.osferi in dogs in Australia was reported by Keep (1951); subsequently Dunsmore and Burt (1972) reported a high prevalence in dingoes in south-eastern Australia. Several other unpublished observations of F.osleri in domestic dogs are known to have occurred in Queensland (W. T. Hall, personal communication) and Western Australia ( M . E. Nairn and G.de Chaneet, personal communication). A 5 year-old white male castrated Boxer dog was presented to one of us (Paterson) with a history of patchy alopecia, vomiting and an ill defined change in demeanor. Clinical examination revealed depression, a stilted gait and rapid respiraAustralian Veterinary Journal, Vol. 54, July, 1978

tion. Results of haematologic and urine analyses were within the normal range. The dog was hospitalised on the following day and over the next 2 days showed progressive incoordination, convulsions, circling and nystagmus. The temperature remained normal throughout the hospitalisation period. A tentative diagnosis of intracranial neoplasia was made and the dog was euthanized. A post-mortem examination revealed infiltration of the third and fourth ventricles of the brain by a greyish red mass, which on microscopic examination was diagnosed as undifferentiated tumour of neuroectodermal origin. Histological examination revealed mild anthracosis in the lungs with mild peribronchiolar lymphoid cuffing. Scattered throughout the alveoli were aggregations of adult nematode parasites which contained larvae (Figure I). Because larvae were readily visible in the uteri of the female worms, and because other morphological features were consistent with their being Strongylida, we concluded that they belonged to the Metastrongyloidea. Because the parasites are clearly not associated with pulmonary arteries it is unlikely that they are A. vasorum. Angiostrongylus cantonensis, a metastrongyloid of rats, was also considered as Mason er al (1976) recorded the presence of larvae of this parasite in the central nervous system (CNS) of dogs in Queensland. In Western Australia Huxtable and Dunsmore (personal communication) have also observed A. 361

A feature of the histological examinations was the virtual absence of any tissue reaction to the nematodes. This implies an excellent host-parasite relationship and makes i t very unlikely that this is an accidental infection with a nematode normally parasitic in the lungs of another species. The life cycles of F. hirrhi and F. osleri are direct (Georgi 1976; Dorrington 1968) and it is likely that transmission is usually from dam to offspring, \bith no prolonged nonparasitic stages. Seberal attempts were made to detect eggs or larbae in the faeccs of the 3 dog.< which had cohabited with the original animal. The Zinc Sulphate Levitation Techniquc described by Georgi er al(1978) was used, but no eggs or larvae were detected. We believe that this is the first report of the presence of Metastrongyloid species other than F. osleri in dogs in Australia and are investigating the prevalence of this infection in Western Australia. W. F. ROBINSON, J . D. DUNSMORE, School of Veterinary Studies, Murdoch Uniberisty. klurdoch. Western Australia. 6153

canronensis in the CNS of a dog that left Queensland I I days earlier. However, there i y no evidence that A . canronensis nor the closely related .4. rnackerrasae of rats reach a gravid state in an ab\ormal site in a n abnormal host, especially in the absence of an inflammatory response. Gravid F. ocleri have never been reported from the lung parenchyma and in histological section. and adults of F. osleri are more than 240 p in diameter: in this case, none exceeded 130 p. Although Dumsmore and Sprat1 (unpublished data) have found quite large immature F. osleri in the lumg parenchyma of an experimentally infected fox, adults have only been found in the vicinity of the tracheobronchial bifurcation. For reasons, it is unlikely that this nematode is F. osleri. .4lthough there are dangers of comparing dimensions taken from histological preparations with those taken from fixed, who nematodes, this is the only source of data available. Georgi and Anderson (IY?!), in their description of F. hirthi state that the body \+idth of females is 58-102 p ; Whitlock (1956) described F. rnilksi females as having a body Hidth of 116-174p With the limited amount of material, i t can only be stated that the body width of this nematode, in histological section, does not exceed 130 pm. No additional useful morphological data was obtained from an examination of 80 serial sections and it is not possible to state whether this nematode is closely related to, or is, F. m i l h i .

A. J . PATERSON, Suanbourne Veterinary Hospital, 2 Debon Road, S\\anbourne, Western Australia, 6010 5 Deceniher I977

References Dorringtoii. J . E . (1968)-0nd. J . ver. Res.. 35: 225. Dunsmore. J . D. and Burt, J . (19?2)- Ausr. vet. J . . 48: 548. Georgi, J . R . (1976)--Science, 144: 735. Georgi, J . R. and Anderson. R. C. (1975)--J. Parasif. 61: 337. Georgi. J . R.. Georgi, M. R., and Cleveland. D. J . ~19?8)-Parasirology: in press. Keep. J . M. (1951)-Ausr. Ler. J.. 27: 43. Mason, K. V., Prescott. C . W . , Kelly, W. K. and Waddell. A. H . (1976)--Ausr. t'ef.J . 52: 295. Osier. H'. f 187Y)- Vererinarian, Lond., 50: 387. Seddon, H. R. (IY67)-in Diseases o f Domesric Animals in Australia, Part I . p 181. IVhrtlock, J . H . (1956)- Il'iener Tierarztl Monarsschr., 43: 730.

EXPERIMENTAL FOOT-ROT, WOOL GROWTH AND BODY MASS Although there have been qualitative reports of poor wool growth in foot-rot. no quantitative measurements have been made. The following is a report of an opportunity to measure the rate of wool growth in foot-rot in adult Merino sheep that were part of an experiment for a different purpose. Eleven wethers and one ewe were di\ided according to body mass into 2 paired groups, one of which was infected with footrot by the method of Egerton er al (1969). The rates of wool growth before and after infection were measured with tattooed patches as described by Barger er a/ (1973). I t was measured in paired infected and uninfected sheep in the infected phase when i t Has estimated that the symptoms of the disease in individual animals were maximal. Body mass was measured week I y . 362

The rate of wool growth Has measured over 27 days before infection and over a mean of 59 days (range 53-67) in the infected phase. At this time, one sheep had severe foot-rot in all 4 feer. with under-running extending to the walls of the hoof in 2 of these. Of the other 5, one had under-running to the hoof walls in 3 feet, whereas there was under-running in 2 feet of the remaining 4 animals. I t was concluded that foot-rot was moderate to severe in these 6 sheep. This conclusion was supported by the comparative changes in body mass. Five of the 6 infected sheep reached a maximum during the fifth week and lost mass thereafter, whereas the sixth animal lost mass from the first week of infection. The mean percentage loss between attainment of their maxima and the end of the experiment was 5.3 T 3.9 (SD)%, compared with

Australian Veterinary Journal, Vol. 54, J u l y , 1978