Roy C. Anderson

IXODES SCAPULARIS SAY ON WHITE-TAILED DEER (Odocoileus virginianus) FROM LONG POINT, ONTARIO

Ixodes scapularis Say was the only species of tick found on white-tailed deer, Odocoileus virginianus, collected at Long Point, Ontario from October 1972 to August 1973. Adults were most abundant from September 1972 to April 1973. Larvae were found throughout the study period except during February. Nymphs were scarce during winter months but fairly common during spring and summer. Most adults were found on the neck and shoulders. Larvae occurred mainly on lower regions of the body and nymphs mainly on the head, shoulders, forelegs and brisket.

CENTRARCHID FISH AS PARATENIC HOSTS OF THE GIANT KIDNEY WORM, DIOCTOPHYMA RENALE (GOEZE, 1782), IN ONTARIO, CANADA

Infective larvae of Dioctophyma renale were found in the hypaxial musculature of pumpkinseed (Lepomis gibbosus L.) from three lakes in Algonquin Provincial Park, Ontario, Canada. This represents the first report of D. renale in centrarchid fish. In the three lakes surveyed prevalence and mean intensity ranged from 5 to 23% and one to two larvae respectively. Larvae elicited a mild granulomatous reaction in pumpkinseed. Two ferrets were each given five larvae from pumpkinseed. Adult D. renale were recovered from the right kidney capsule of ferrets 108 and 134 days post-infection. An opening in the ventral surface of the right kidney capsule was present in one ferret. Chronic peritonitis was associated with eggs of D. renale and cellular debris which probably entered the abdominal cavity from the right kidney capsule.

Myxosporidan parasites for pumpkinseed (Lepomis gibbosus L.) from Ontario.

Five species of myxosporideans were found in pumpkinseed (Lepomis gibbosus L.) from Ryan Lake, Algonquin Park, Ontario. Myxobolus osburni Herrick 1936 was found in pancreatic tissue. Myxobilatus ohioensis (Herrick 1941) Davis 1944 was found in the ureters and urinary bladder. Three new species are described, namely, Myxobolus uvuliferis sp. n. (in the fibrous capsule surrounding the metacercariae of Uvulifer ambloplitis (Hughes 1927), Myxobolus magnaspherus sp. n. (in the parietal peritoneum) and Myxobolus dechtiari sp. n. (in the gills). Myxobolus uvuliferis sp. n. is most similar to M. osburni, but its spores are subspherical and not spherical. Myxobolus magnaspherus sp. n. is most similar to Myxobolus gigas Auerbach 1906, but its spores are wider than long, and they have exceedingly long polar filaments. Myxobolus dechtiari sp. n. is similar to Myxobolus karelicus Petruschewsky 1940 but it lacks an intercapsular appendix.

Why do fish have so few roundworm (nematode) parasites

SynopsisAlthough they are the oldest and most diverse members of the subphylum, the fishes have relatively few nematode parasites in comparison with other vertebrate classes. It is hypothesized that this paucity of parasite species has occurred because nematode parasites first evolved in terrestrial hosts and only a few lines of these parasites were able to transfer to fish after the appearance of heteroxeny (use of intermediate hosts) and paratenesis (use of transport hosts). The inability of nematodes to initiate parasitism in aquatic ecosystems restricted fish parasites mainly to forms first adapted to terrestrial vertebrates and at the same time deprived large groups of aquatic invertebrates such as the crustaceans, annelids and molluscs of a nematode parasite fauna.

DEVELOPMENT OF THE STOMACH WORM, OBELISCOIDES CUNICULI (GRAYBILL), IN LAGOMORPHS, WOODCHUCKS AND SMALL RODENTS

The parasitic development of Obeliscoides cuniculi multistriatus Measures and Anderson, 1983 was studied in New Zealand white rabbits (Oryctolagtis cuniculns). Third-stage larvae exsheathed within 24 hr. The third molt occurred 3 days and the fourth 8–11 days post-infection. All worms were fifth stage 14 days post-infection. Males were mature at 16 days and copulation occurred in 15–16 days. Females were gravid at 18 days. The prepatent period was 16–22 days. The patent period was 61–118 days and males lived longer than females. All stages were found in the mucosa except the fifth which was found lying on the mucosal surface within a layer of mucus. Petechiae were the only lesions seen in experimentallv infected rabbits. Patent infections of O. c. multistriatus were established experimentally in infected woodchucks (Marmota monax), snowshoe hares (Lepus americanus) and cottontail rabbits (Sylvilagus floridanus). Patent infections of O. c. cuniculi were established experimentally in snowshoe hares. Patent infections of O. c. multistriatus did not appear in experimentally infected HPB white (Swiss Webster) mice (Mus musculus), Wistar rats (Rattus norvegicus), H.O.R. F1 Syrian hamsters (Mesocricetus auratus), H.O.R. F1 smooth-haired guinea pigs (Cavia porcellus) and H.O.R. F1 gerbils (Meriones unguiculatus).

CHARACTERISTICS OF NATURAL INFECTIONS OF THE STOMACH WORM, OBELISCOIDES CUNICULI (GRAYBILL), IN LAGOMORPHS AND WOODCHUCKS IN CANADA

Wild lagomorphs and woodchucks collected predominantly in southern Ontario, Canada were examined for subspecies of Obeliscoides cuniculi (Graybill). Obeliscoides cuniculi multistriatus was found in snowshoe hares (Lepus americanus). Obeliscoides cuniculi cuniculi was found in cottontail rabbits (Sylvilagus floridanus), European hares (Lepus capensis) and woodchucks (Marmota monax). Prevalence of Obeliscoides cuniculi multistriatus in snowshoe hares was 100% and mean intensity (and range of intensity) was 760 (9–4,198) in Lindsay, Ontario in 1980. Mean intensity in hares varied trimonthly. The highest mean intensity of worms occurred in spring when most worms were adult. Transmission occurred mainly in spring. Most worms present in fall (70%) and winter (54%) were fourth stage. Immature fifth-stage and gravid females were present in hares during fall and winter. Prevalence and mean intensity of O. c. cuniculi in cottontails was 15% and 29 (1–118). Prevalence and mean intensity of O. c. cuniculi in woodchucks was 6% and 56 (16–118). European hares were infected with O. c. cuniculi, prevalence was 10% and mean intensity was 60 (36–83). In Ontario woodchucks and European hares were common in areas frequented by cottontail rabbits and probably acquired sporadic infections of O. c. cuniculi from infected cottontails.

New and described species of nematodes from shorebirds (Charadriiformes) collected in spring in Iceland

The following were found in shorebirds collected during late April and early May shortly after their arrival in Iceland. Voguracuaria lankesteri n. g., n. sp. was found in the oesophagus of eight of 20 whimbrels Numenius p. phaeopus. The new genus resembles Syncuaria, but males have an area rugosa and small caudal alae, females are didelphic and the vulva is distant from the anus. Also, Syncuaria spp. occupy the gizzard rather than the oesophagus. Skrjabinocerca europaea n. sp. was found in the oesophagus of six of 22 ringed plovers Charadrius h. hiaticula (type-host) and in one dunlin Calidris alpina schinzii. The new species is readily distinguished by the presence of a cuticular flange at the distal end of the left spicule, its slightly recurrent cordons and its longer right spicule. “Skrjabinocerca prima” previously reported from American avocets Recurvirostra americana in North America is recognised as a distinct species and named S. americana n. sp. Ancyracanthopsis shikhobalovi found in the gizzard of whimbrels and Viktorocara charadrii found in the gizzard of ringed plovers are redescribed. Other nematodes found in the birds were Chevreuxia revoluta, Cosmocephalus capellae, C. obvelatus, Echinuria sp., Streptocara sp., Ancyracanthopsis parvialatus, Schistorophus cornutus, S. cirripedesmi, Sciadiocara bihamata, Viktorocara limosae, Microtetrameres sp., Tetrameres sp., Stellocaronema skrjabini and Porrocaecum semiteres.

OBSERVATIONS ON TURGIDA TURGIDA (RUDOLPHI, 1819) (NEMATODA: PHYSALOPTEROIDEA) IN THE AMERICAN OPOSSUM (DIDELPHIS VIRGINIANA)

Turgida turgida is a common parasite of the stomach of the American opossum in Florida. Worms were usually found attached to the greater curvature of the corpus of the stomach. Ulcers always occurred at the site of the attachment. Large ulcers were associated with groups of adult parasites and were found in the oldest experimental infections. Turgida turgida fed on food within the stomach of the opossum and attached to the stomach wall when not feeding. Third- and fourth-stage larvae were found in opossums in Florida mainly from May to August suggesting that this is a major period of transmission.

Development of Pelodera strongyloides (Schneider, 1860) Schneider, 1866 (Nematoda: Rhabditidae) in culture.

Dauerlarvae of Pelodera strongyloides, recovered from two species of lemmings, Dicrostonyx groenlandicus (Traill) and Lemmus trimucronatus (Richardson) trapped at Eskimo Point, N.W.T, were cultured on agar medium with E. coli. Development from egg to adult stage was followed. Eggs hatched between 22 and 26 hours at 22 degrees C. The first moult occurred 24 to 28 hours after the eggs hatched, the second at 40 to 48 hours, the third at 60 to 64 hours and the fourth at 84 to 88 hours at 22 degrees C. Adults lived approximately 5 to 6 days and females oviposited for 2 to 3 days during this time. All stages were measured and described. The effect of temperature on development was examined. Dauerlarvae survived freezing temperatures, short periods of desiccation and prolonged periods without food.

The development, route of migration, and pathogenesis of Filaroides martis in mink.

Third-stage larvae of F. martis entered the gastric glands of mink (Mustela visoi) where they molted on the 3rd or 4th days after infection. Fourth-stage larvae penetrated the lamina propria and entered the submucosa where they were closely associated with the adventitia of blood vessels. Larvae passed through the external muscle layers of the stomach in the adventitia of the small gastric arteries and had molted to the fifth stage in the gastric subserosal fat by 11 days after infection. Subadults passed via the adventitia of the gastric arteries and the pancreatico-duodenal artery to the base of the coeliac axis at its junction with the dorsal aorta. The worms, in the adventitia of the dorsal aorta, moved forward through the diaphragm to the base of the heart. At the base of the heart the worms left the adventitia of the dorsal aorta and transferred to the adventitia of the pulmonary arteries. They moved along the adventitia of the pulmonary arteries and reached the lung parenchyma as early as 15 days after infection. The worms grew markedly in the connective tissue surrounding the arteries and associated bronchi. Finally the tail of the female was forced through the bronchial epithelium. First-stage larvae were deposited on the bronchial epithelium approximately 40 days after infection. F. martis (Werner, 1782), a common nematode parasite of wild mink (Mustela vison) in North America, produces nodules at the hilus of the lobes of the lung. A prevalence of 45% in wild mink was recorded in Ontario by Anderson (1962). First-stage larvae, passed in the feces of the final host, develop in several species of gastropods (Petrow and Gagarin, 1937; Anderson, 1962); the third stage is reached in about 16 to 18 days (Anderson, 1962). Anderson (1962) showed that the prepatent period of F. martis in mink in Ontario is approximately 41 days. He noted that infections of F. martis in mink are often mixed with P. pridhami whose prepatent period is about 20 days. The intramammalian development and migration of F. martis have not previously been studied. The aim of the present work was to determine the route of migration, development, and pathogenesis of F. martis in mink during the prepatent period. MATERIALS AND METHODS Two terrestrial land snails, Mesodon thyroidus and Triodopsis albolabris, were cultured as intermediate hosts. The snails were kept in terraria, the floors of which were covered with moss. The snails were fed commercial cat food, lettuce, and oyster shell. First-stage larvae were recovered from feces by the Baermann technique. Larvae were washed and resuspended to a concentration of 15,000/ml Received for publication 25 November 1969. * Department of Pathology. t Department of Zoology. in a 0.65% solution of sodium chloride containing 1,000 international units of penicillin G potassium and 1,000 fig of streptomycin sulfate per ml. Snails, approximately 2.4 cm in diameter, were injected with 0.2 ml of this larval suspension (approx 3,000 larvae) using a 1-ml disposable tuberculin syringe and a 25-gauge hypodermic needle. The needle was introduced into the snail just anterior to the shell, directed into the posterior area of the foot, and the solution injected as rapidly as possible. The snails were replaced in the terraria for at least 21 days before being used for the recovery of infective larvae. Infective larvae were recovered by digesting the soft tissues of the snails with pepsin hydrochloride at 37 C in a Baermann funnel. Mink were obtained from the colony of the Ontario Veterinary College. Kits were weaned at 6 weeks and vaccinated against canine distemper, viral enteritis, and botulism. They were kept in standard mink cages raised approximately 2 ft from the ground and fed a standard mink ration. Mink were inoculated under ether anesthesia by placing the larvae directly in the stomach via a stomach tube. One mink was killed at each 2-day interval from 1 to 13 days after infection and then at 4-day intervals from 13 to 41 days after infection. Mink were killed with sodium pentobarbital (180 mg/ 2.3 kg body weight). A post-mortem examination was carried out and the following tissues fixed in formalin, sectioned, and stained with hematoxylin and eosin: esophagus, stomach, small intestine, large intestine, mesenteric lymph node, pancreas, kidney, liver, spleen, lung, diaphragm, trachea, heart, brain, and spinal cord.