The sea louse Lepeophtheirus acutus (Caligidae, Siphonostomatoida, Copepoda) as a pathogen of aquarium-held elasmobranchs.

Lepeophtheirus acutus Heegaard, 1943 (Caligidae, Siphonostomatoida, Copepoda), was collected from or observed on four of six elasmobranch species held at Burgers' Zoo (Arnhem, The Netherlands). Circumstantial evidence suggested that a zebra shark, Stegostoma fasciatum (Hermann), from the wild carried the infection into the facility, where copepods reproduced and colonized additional hosts. Copepods typically attached on and about the eyes, in the mouth and occasionally about the cloaca and on the claspers. Severe ocular lesions were associated with infections on zebra sharks, a grey reef shark, Carcharhinus amblyrhynchos (Bleeker), whitetip reef sharks, Triaenodon obesus (Rüppell), and giant shovelnose ray, Rhinobatos typus Bennett, while blacktip reef sharks, Carcharhinus melanopterus (Quoy & Gaimard), and blacktip sharks, Carcharhinus limbatus (Valenciennes), living in infested aquaria showed no sign of infection. Water treatments using trichlorfon were considered primarily responsible for the eradication of copepods from hosts and infested aquaria. This case is the first report of a copepod infection being closely associated with disease and death of an aquarium-held elasmobranch. Given its ability to infect a wide variety of elasmobranchs and promote life-threatening lesions on some hosts, L. acutus should be considered a dangerous pathogen of captive elasmobranchs.

Stable-isotope comparisons between embryos and mothers of a placentatrophic shark species.

Stable nitrogen (delta(15)N) and carbon (delta(13)C) isotopes of Atlantic sharpnose shark Rhizoprionodon terraenovae embryos and mothers were analysed. Embryos were generally enriched in (15)N in all studied tissue relative to their mothers' tissue, with mean differences between mother and embryo delta(15)N (i.e. Deltadelta(15)N) being 1.4 per thousand for muscle, 1.7 per thousand for liver and 1.1 per thousand for cartilage. Embryo muscle and liver were enriched in (13)C (both Deltadelta(13)C means = 1.5 per thousand) and embryo cartilage was depleted (Deltadelta(13)C mean = -1.01 per thousand) relative to corresponding maternal tissues. While differences in delta(15)N and delta(13)C between mothers and their embryos were significant, muscle delta(15)N values indicated embryos to be within the range of values expected if they occupied a similar trophic position as their respective mothers. Positive linear relationships existed between embryo total length (L(T)) and Deltadelta(15)N for muscle and liver and embryo L(T) and Deltadelta(13)C for muscle, with those associations possibly resulting from physiological differences between smaller and larger embryos or differences associated with the known embryonic nutrition shift (yolk feeding to placental feeding) that occurs during the gestation of this placentatrophic species. Together these results suggest that at birth, the delta(15)N and delta(13)C values of R. terraenovae are likely higher than somewhat older neonates whose postpartum feeding habits have restructured their isotope profiles to reflect their postembryonic diet.

Gill lesions associated with Erpocotyle tiburonis (Monogenea: Hexabothriidae) on wild and aquarium-held bonnethead sharks (Sphyrna tiburo).

Gill lesions associated with infections of Erpocotyle tiburonis (Brooks, 1934) (Monogenea: Hexabothriidae) on wild bonnethead sharks (Sphyrna tiburo (L., 1758) (Carcharhiniformes: Sphyrinidae)) were compared with those on aquarium-held ones using light and scanning electron microscopy. Uninfected gill filaments had slender, triangular, smooth-surfaced lamellae and interlamellar water channels that were approximately equal in size. Four wild sharks were each infected by 3-11 widely separated adult E. tiburonis, and 1 of these sharks hosted a juvenile specimen. Lamellae flanking or touching adult E. tiburonis were pushed aside or bent, but were otherwise identical to those of uninfected filaments. Two aquarium-held sharks were each infected by hundreds of juvenile and adult E. tiburonis. In these sharks, lamellae near juveniles were pushed apart or bent, but were otherwise normal, whereas a thick, ragged-surfaced layer of hyperplastic epithelium both filled interlamellar water channels and partially or completely covered lamellae near adults. Results of this study suggest that the intense infections of E. tiburonis were facilitated by captivity and caused severe hyperplastic lesions that ultimately led to the death of the sharks by reducing or blocking the respiratory water flow over lamellae and thus reducing the exchange of gases and ions across the lamellar epithelium. In contrast, the wild sharks were infected by fewer worms and exhibited relatively minor lesions.

Kroeyerina deetsorum n. sp. (Copepoda: Kroyeriidae) from the olfactory sacs of Atlantic sharpnose sharks (Rhizoprionodon terraenovae) captured in the Gulf of Mexico and northwestern Atlantic and first report of copepodids representing Kroyeriidae.

Kroeyerina deetsorum n. sp. (Copepoda: Kroyeriidae) is described from female and male specimens collected from the olfactory sacs of Atlantic sharpnose sharks, Rhizoprionodon terraenovae (Richardson, 1836), captured in the Gulf of Mexico and northwestern Atlantic. Kroeyerina deetsorum is easily distinguished from known congeners by the extremely small size of its adults (i.e., females about 1.2 mm total length and males about 1.0 mm total length). Kroeyerina deetsorum is also distinguished from its congeners by possessing a subquadrate rostrum without lobes or upturned horns. It is suspected that K. deetsorum belongs to a clade within Kroeyerina whose members only infect sharks. This report also provides first descriptions of a nauplius representing Kroeyerina and copepodids representing Kroyeriidae. The early-stage copepodid of K. deetsorum lacks a frontal organ and frontal filament and uses its chelate antennae to attach to its host.

Skin lesions caused by Dermophthirius penneri (Monogenea: Microbothriidae) on wild-caught blacktip sharks (Carcharhinus limbatus).

Skin lesions caused by the ectoparasite Dermophthirius penneri Benz, 1987 (Monogenea: Microbothriidae) on 2 wild-caught blacktip sharks (Carcharhinus limbatus) from the northern Gulf of Mexico were studied using light and scanning electron microscopy. Grossly, lesions appeared as multifocal, well-demarcated, ovoid or irregularly shaped, light gray patches of skin. Scanning electron microscopy of lesions revealed gaps between placoid scales apparently created by detachment and loss of placoid scales, rotated and tilted placoid scales with blunt distal tips and shallow ridges, and a frayed epithelium that covered some placoid scales and filled some spaces between placoid scales. Light microscopy of lesions revealed epithelial hyperplasia accompanied by dermal infiltrates of moderate numbers of loosely arranged lymphocytes interposed between collagen bundles in the superficial layers of the stratum compactum. This report provides the first details of microbothriid skin lesions on wild sharks. Our results indicate that D. penneri caused chronic skin lesions not associated with bacterial infection or severe, debilitating, skin disease in the studied sharks.

Margolisius abditus n. gen., n. sP. (Copepoda: Lernaeopodidae) from gill lamellae of a remora (Remora remora) collected in the Gulf of California.

Margolisius abditus n. gen., n. sp. (Copepoda: Lernaeopodidae) is described from female specimens collected from gill lamellae of a remora, Remora remora (L.), captured in the Gulf of California near Punta Arena, Baja California. Comparison of this species with 13 lernaeopodid genera with which it shares (a) absence of posterior trunk processes; (b) presence of a relatively long cylindrical cephalothorax, usually reflected along the dorsal surface of the trunk; and (c) a marine habitat showed that it cannot be placed in any of them, thus necessitating establishment of a new genus. Margolisius abditus n. sp. is the smallest known lernaeopodid species, its ovigerous females measuring about 0.5 mm in total length.

Dionchus postoncomiracidia (Monogenea: Dionchidae) from the skin of blacktip sharks, Carcharhinus limbatus (Carcharhinidae).

Postoncomiracidia of Dionchus sp. are described from specimens collected from the skin of 2 blacktip sharks Carcharhinus limbatus, captured in the northern Gulf of Mexico. The parasites resemble nonciliated oncomiracidia hatched from eggs laid by Dionchus sp. on gills of a cobia Rachycentron canadum and adults of Dionchus remorae that were collected from gills of a common sharksucker Echeneis naucrates, captured in association with a third blacktip shark. The hamuli of the postoncomiracidia were morphologically similar to those of adult D. remorae. This is the first report of dionchids from an elasmobranch and from a location other than the gills. These findings support the idea that some dionchid oncomiracidia colonize the skin of sharks or other aquatic vertebrates that sponsor remoras, prior to transferring to other remoras and maturing.

New host and ocean records and remarks on the morphology and behavior of Jusheyus shogunus (Copepoda: Siphonostomatoida: Eudactylinidae.

Jusheyus shogunus Deets and Benz, 1987 (Copepoda: Eudactylinidae) is reported from wreckfish, Polyprion americanus (Schneider, 1801) collected from widely separated locations in the north Atlantic. This represents a new host record and new ocean report for this parasite. Examination of male and female copepods allowed some confusion regarding the morphology of J. shogunus to be eliminated. Jusheyus shogunus possesses a cephalothorax rather than a cephalosome and its dorsal styliform processes are connected by an internal bridging sclerite and an external dorsal plate that is hinged to its cephalothorax. Each process also articulates with its own internal ventral sclerite. A series of muscles services these structures, and comparisons of the dorsal styliform processes of J. shogunus with the dorsal stylets of Kroyeria spp. revealed some morphological similarities. Adult female J. shogunus in the study collection varied in size from 2.16 to 4.97 mm total length, and smaller and larger specimens presented somewhat different body forms. Most egg sacs contained multiseriately arranged eggs; however, several specimens possessed a sac whose distal portion contained uniseriately arranged eggs and whose proximal portion contained 2 rows of eggs. Jusheyus shogunus attaches to the gill filament lamellae of its hosts using its second antennae and maxillipeds. The dorsal styliform processes can be erected by either directly raising them or by flexing the cephalothorax at its junction with the first free thoracic segment. In either case the tips of the processes can engage 1 to several lamellae on the adjacent gill filament to help secure the parasite.

Morphology of the deep-sea copepod Bobkabata kabatabobbus (Lernaeosoleidae: Poecilostomatoida) and amended diagnosis of Lernaeosoleidae.

New morphological information on the deep-sea parasitic copepod Bobkabata kabatabobbus Hogans and Benz, 1990 (Lernaeosoleidae: Poecilostomatoida) is provided based on 2 newly discovered, complete specimens collected from a pallid sculpin, Cottunculus thomsoni (Gunther, 1882), captured in water 1,463 m deep in Welker Canyon off Rhode Island (western North Atlantic). The first antennae of both specimens were tiny, indistinctly segmented, and armed with spiniform setae. Terminal segments of the second antennae were robust hooks and were impossible to disengage from the host without severing them from their basal sockets. A simple orifice without any associated appendages may have represented the mouth. Both specimens were transformed adult females and each was embedded in the flesh of their scaleless host up to where the pregenital trunk began to broaden into its characteristic horseshoe shape. Whereas each copepod's bulbous cephalothorax appeared to be the primary attachment device, the powerfully hooked second antennae seemed positioned to facilitate the application of the presumed mouth to the host. A revised family diagnosis for Lernaeosoleidae Hogans and Benz, 1990 is provided that primarily differentiates Lernaeosoleidae from the closely allied Chondracanthidae H. Milne-Edwards, 1840 and other poecilostomatoids based on the absence of mandibles, first and second maxillae, maxillipeds, and thoracic legs 1-4 in lernaeosoleids.

Trebius shiinoi n. sp. (Trebiidae: Siphonostomatoida: Copepoda) from uteri and embryos of the Japanese angelshark (Squatina japonica) and the clouded angelshark (Squatina nebulosa), and redescription of Trebius longicaudatus.

Trebius shiinoi n. sp. is described from females and males collected from the uterine linings and on embryos within the uteri of 2 near-term Japanese angelsharks (Squatina japonica Bleeker, 1858) captured in Suruga Bay, off central Japan, and from female specimens reported by Shiino in 1963 that were found on embryos of the clouded angelshark (Squatina nebulosa Regan, 1906) captured off Shirahama, central Japan. Shiino identified his specimens as Trebius longicaudatus Shiino, 1954. However, our comparisons between Shiino's specimens and those newly collected revealed both to represent the same species, and comparisons of these specimens to 5 syntypes of T. longicaudatus and to published information detailing other Trebius species revealed them to be a new species that differs most notably from its congeners by the enormous length of its transformed adult female's abdomen and by the presence of a distinctive nublike seta on her caudal ramus. Trebius shiinoi n. sp. is an unusual copepod because it is an endoparasite of adult female angelsharks as well as an ectoparasite of embryo angelsharks, and it is proposed that flushing of the uterine-cloacal chambers of clouded angelsharks and Japanese angelsharks may facilitate T. shiinoi infections. A redescription of T. longicaudatus is also provided.

New host and ocean records for the copepod Ommatokoita elongata (Siphonostomatoida: Lernaeopodidae), a parasite of the eyes of sleeper sharks.

Seven of 8 Pacific sleeper sharks (Somniosus pacificus Bigelow and Schroeder, 1944) captured in Prince William Sound, Alaska, were actively infected, and all 8 had been at one time infected with the parasitic copepod Ommatokoita elongata (Grant, 1827) (Siphonostomatoida: Lernaeopodidae). Active infections consisted of adult females and chalimus larvae that had attached to the corneas of the sharks' eyes. This report documents a new host record and possibly the only reliable record of this parasite from a host other than the Greenland shark, Somniosus microcephalus (Bloch and Schneider, 1801). It also documents the first time O. elongata has been identified outside of the Atlantic Ocean or its locally adjacent straits and seas.

Redescription of Argulus melanostictus (Branchiura: Argulidae), a parasite of California grunion (Leuresthes tenuis: Atherinidae), with notes regarding chemical control of A. melanostictus in a captive host population.

Adult male and female Argulus melanostictus Wilson, 1935 are redescribed based on detailed examinations of a syntype and recently obtained specimens of both sexes collected from California grunion, Leuresthes tenuis, captured in nearshore Pacific waters at Monterey, California. A 14-16-hr seawater bath containing 0.5 microliter/L trichlorfon administered once weekly for 3 wk killed A. melanostictus while not noticeably harming grunion.

Eficácia de soluçäo oral de ivermectin contra larvas de Dermatobia hominis (Linnaeus Jr. 1871) em bovinos / Efficacy of ivermectin oral solution in cattle against larval stages of Dermatobia hominis (Linnaeus Jr. 1781)

Os resultados do presente experimento, realizado em duas fazendas do município de Campinas, SP, demonstram que o ivermectin, quando aplicado por via oral, numa única dose de 200 mcg/kg de peso vivo, é altamente eficaz no tratamento e controle dos estágios parasitários das larvas de D. hominis (bernes) em bovinos

Efficacy of ivermectin delivered from an intraruminal sustained-release bolus against natural infestations of five African tick species on cattle.

The efficacy of ivermectin delivered by an orally administered prototype sustained-release bolus over approximately 90 days was evaluated against natural infestations of five African tick species. Twenty cattle, allocated by restricted randomization based on counts of standard Boophilus decoloratus, were allocated to two groups and were either given an ivermectin bolus or designated as non-medicated controls. All cattle grazed a single pasture of native grasses for 20-40 days before treatment and until trial termination. Starting on Days 27, 40, 68 and 82 after bolus administration, four replicates were confined to individual tick-collection stanchions for 4 to 5-day periods. Ticks recovered from these cattle were counted by species, sex, and stage and degree of repletion; engorged females were weighed and incubated to determine the number which oviposited. For the other replicates, half-body counts of adult ticks (classified by species, sex and degree of repletion by females) were made at 1- and 2-week intervals through Day 90. Among replicates confined to stanchions periodically, fewer (P less than 0.05) engorged adult female B. decoloratus, Hyalomma spp., Rhipicephalus appendiculatus and Rhipicephalus evertsi evertsi were collected from bolus-treated cattle than from controls. Numbers of engorged adult female Amblyomma hebraeum were reduced, but differences were not statistically significant (P greater than 0.10). Among cattle maintained continuously on pasture, tick numbers were reduced on the ivermectin-treated groups. A significant (P less than 0.05) treatment by linear time effect was seen for all adult ticks counted except R. appendiculatus. A significant (P less than 0.05) treatment by quadratic time effect was seen for A. hebraeum, B. decoloratus and R. evertsi evertsi, and overall treatment differences were significantly different (P less than 0.05) for these species. The differences tended to increase with time. Except for Boophilus, reductions in tick numbers on treated animals relative to controls were not readily apparent. There were no adverse reactions attributable to ivermectin treatment or the presence of the bolus. Each treated animal retained its bolus throughout the trial, based on metal detection.

The sexual stages of Eimeria wyomingensis Huizinga and Winger, 1942, in experimentally infected calves.

Seven of 12 calves given 10(6) Eimeria wyomingensis sporulated oocysts had sexual stages of the parasite when examined at necropsy. Clinical signs of coccidiosis were not observed in any calf. Sexual stages were located in host cells in the lamina propria of the villi in the terminal small intestine. Infected host cells underwent nuclear and cytoplasmic hypertrophy. Immature microgamonts usually had folded cytoplasm and an overall spherical to elongate shape. Mean length and width +/- SEM of immature microgamonts were 43.3 +/- 1.6 by 29.0 +/- 1.1 micron. Mature microgamonts contained hundreds of microgametes, lacked visible cytoplasmic folds, and measured 52.8 +/- 4.7 by 43.0 +/- 4.2 micron. Macrogamonts were spherical to ovoid and had a large nucleus and prominent nucleolus. Immature macrogamonts without visible wall-forming bodies measured 16.0 +/- 0.5 by 13.3 +/- 0.2 micron. Mature macrogamonts had 3-8-micron eosinophilic wall-forming bodies and measured 24.6 +/- 0.7 by 19.6 +/- 0.8 micron. Oocysts were ovoid and had a 2-3-micron-thick eosinophilic oocyst wall. A micropyle was present in appropriately sectioned oocysts. Oocysts measured 27.7 +/- 1.7 by 19.3 +/- 0.8 micron. The sexual stages of E. wyomingensis are compared to those described previously for species of Eimeria infecting the bovine small and large intestines.

Prophylactic efficacy of an ivermectin sustained-release bolus against challenge exposure with gastrointestinal and pulmonary nematode infective larvae in calves.

Twelve Holstein calves were used to determine the prophylactic efficacy of ivermectin against challenge exposure with gastrointestinal and pulmonary nematodes. Two groups of 6 calves (mean body weight, 205 kg) each were formed by restricted randomization according to body weight. Group-1 calves served as nonmedicated controls. Each calf of group 2 was orally given one prototype sustained-release bolus designed to deliver ivermectin at a continuous daily dose of 8 mg. Third-stage nematode infective larvae were given to the calves on posttreatment days 28 and 42. The calves were euthanatized 77 or 78 days after treatment. Ivermectin was 100% effective (P less than 0.05) in preventing the establishment of infection by Haemonchus placei, Ostertagia ostertagi, Cooperia spp (C punctata, C oncophora, C surnabada), Nematodirus helvetianus, Oesophagostomum radiatum, and Dictyocaulus viviparus and was greater than 99% effective against Trichostrongylus axei. Incidental infection by Trichuris spp was reduced by 94% (P = 0.08).

Comparative efficacy of clorsulon and albendazole against Fasciola hepatica in cattle.

In a dosage-confirmation trial, anthelmintic activities of clorsulon and albendazole against Fasciola hepatica were evaluated and compared. Twenty-eight cattle (8 to 12 months old) with natural F hepatica infections were randomly allotted to 4 groups of 7 cattle each: group 1, no treatment (controls); group 2, clorsulon suspension given orally at 3.5 mg/kg of body weight; group 3, clorsulon suspension given orally at 7 mg/kg; and group 4, albendazole paste given orally at 10 mg/kg. At necropsies, performed 7 and 8 days after treatment, control cattle harbored a geometric mean of 133.2 F hepatica, 16.0 of which were immature. Clorsulon administered at 3.5 mg/kg or 7 mg/kg resulted in greater than 99% removal of F hepatica, including immatures. Albendazole treatment resulted in a 76% overall reduction in F hepatica, including a 91% reduction of immatures. Fascioloides magna also were found in the cattle, but neither clorsulon nor albendazole caused significant reductions of the parasite. Adverse reactions to the 2 drugs were not observed.

Efficacy of ivermectin against the mange mite Sarcoptes scabiei var suis in pigs.

The efficacy of ivermectin administered by esophageal intubation in a single dose was evaluated against the mange mite Sarcoptes scabiei var suis in 24 naturally infested pigs. Six pigs were allocated to each of the 4 treatment groups. Control (group 1) pigs were given nonmedicated water, group 2 were given ivermectin at 300 micrograms/kg of body weight, group 3 were given ivermectin at 400 micrograms/kg, and group 4 were given ivermectin at 500 micrograms/kg. The pigs were examined for S scabiei before treatment and on days 7, 14, 21, and 28 after treatment. Of the 18 ivermectin-treated pigs, 10 had no live S scabiei recovered on day 7 after treatment, 16 had none on day 14, 18 had none on day 21, and 16 had none on day 28. All 6 nonmedicated control pigs had live S scabiei recovered on days 7 and 21, and 5 control pigs had mites on days 14 and 28. The single administration of ivermectin given by esophageal intubation was highly effective in reducing the number of S scabiei at all dose levels tested. The pooled ivermectin-treated groups had significantly (P less than 0.01) fewer mites than the control group on all posttreatment examination days. There were no statistically significant differences among the ivermectin dose levels.

Experimentally induced Cooperia oncophora infection in calves: lymphocyte blastogenic and delayed hypersensitivity responses.

Lymphocytic responses in peripheral blood and visceral lymph to Cooperia oncophora antigen and skin tests were determined in 35 Holstein male calves that were inoculated orally with single or multiple doses of C oncophora infective larvae. Several calves were vaccinated or given immune serum before larvae were inoculated. Antigen-specific in vitro blastogenesis of blood and lymph lymphocytes and delayed-type hypersensitivity reactions were observed in several inoculated, vaccinated, and/or passively immunized calves. Most calves that had delayed skin reactions also had in vitro lymphocyte responses to C oncophora antigen. The lymphocyte and skin responses were inconsistent and variable in time of onset--the earliest lymphocyte response occurring 7 days after calves were inoculated. A cellular immune response was induced by both dermal vaccination and oral inoculation; however, passive immunization by IV administration of immune serum simultaneously with inoculation did not have an apparent effect on the cellular response, as measured by the lymphocyte blastogenesis test or dermal testing. Although cellular immune responses were observed in several calves infected with C oncophora, there was no apparent relationship between the specific responses and number of nematodes establishing infection in calves after either single- or multiple-dose oral inoculations.