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At least 595 records · Page 33Linked to original sources

Biological tags for stock separation in Pacific herring Clupea harengus pallasi in California.

A survey of the parasites of Pacific herring (Clupea harengus pallasi) off northern California identified 1 species of Acanthocephala, 1 species of Cestoda, 2 species of Copepoda, 1 species and 1 family of Digenea, 3 species of Nematoda, and 3 species of Protozoa. From this survey, Lacistorhynchus dollfusi (Cestoda), Parahemiurus merus (Digenea), and Anisakis simplex, Contracaecum sp., Hysterothylacium sp. (Nematoda) were selected as potential tags. Herring were collected in Tomales, San Francisco, and Monterey bays for the following 9 yr and examined for these select parasites. The results suggest that these parasites can be used to distinguish the spawning stocks of San Francisco and Tomales bays. The distribution of the definitive hosts of the respective parasites suggests that the Tomales Bay fish are offshore during the nonbreeding season and the San Francisco Bay fish onshore. The similarity in parasitism between San Francisco Bay and the nonspawning population in Monterey Bay suggests that these 2 populations represent a single stock.

Animals↗

Immunity and genetics: their relation to control of parasitic zoonoses.

Effective control of parasitic zoonoses will ultimately require a combination of several approaches, including hygiene/sanitation, pasture management, chemotherapy and immunoprophylaxis. Development of vaccines, and other approaches to improving protective immunity, require a detailed understanding of parasite immunogenicity and host immune responsiveness. It is increasingly recognized that there is considerable variation in both of these parameters, and that this variation is genetically determined. Recent studies in this area and the consequences for control are discussed.

Animals↗

[Myxozoa as parasites of the central nervous system of fishes].

Myxosporea species in the central nervous system of fish and host-parasite interactions are described. Whereas parasites living in the nervous tissue itself do not induce clinical signs or host reactions, Myxosporea localized in neighbouring mesenchymatous tissues (blood vessels, cartilages, meninges) may induce disease of economic significance.

Animals↗

Metabolic changes in the rumen following protozoal inoculation of fauna-free sheep fed a corn silage diet supplemented with casein or soybean meal.

Fauna-free wethers were fed bi-hourly a corn silage diet containing casein or soybean meal as a protein supplement. The wethers were inoculated via rumen cannula with a mixed population of ruminal ciliate protozoa. Ruminal fluid was sampled daily for 4 d before and for 13 d (and on d 28) after inoculation. Protozoal populations reached peak numbers on d 8 and decreased to new levels after d 9 for wethers on both supplements. Protozoa decreased (P less than 0.01) the concentrations of total volatile fatty acids, increased (P less than 0.01) the pH and decreased (P less than 0.01) he concentrations of total and non-ammonia nitrogen in ruminal fluid. The concentrations of ammonia nitrogen increased with increasing numbers of protozoa for wethers on both supplements, but the concentrations decreased after d 7 to approximately pre-inoculation levels for the casein-supplemented diet. The increasing numbers of protozoa were associated with the increased concentrations of total and free alpha-amino nitrogen (P less than 0.01) and sulfide (P less than 0.05) and with the decreased concentrations of soluble Cu (P less than 0.05) in the ruminal fluid in soybean meal-supplemented wethers but not in those receiving casein. It was concluded that dietary proteins with differing physical characteristics are metabolized to a different extent by ruminal ciliate protozoa, which in turn can affect the metabolism of other dietary nutrients such as nitrogen and sulfur and contribute to copper-sulfur interaction.

Ammonia↗

Avian hematozoa from west-central Bolivia.

A total of 641 birds representing 135 species of 25 families from Noel Kempff Mercado National Park in west-central Bolivia was examined for hematozoa; only 33 (5.1%) harbored blood parasites. Microfilariae were the most commonly encountered hematozoans, followed, in numerical sequence, by species of Haemoproteus and Plasmodium; Trypanosoma, Atoxoplasma, and Hepatozoon were seen infrequently. The survey included 13 new host-parasite records, and 58 species of birds were examined for blood parasites for the first time; 43 were parasite-free. The low prevalence of parasitism recorded in this survey is compared to other areas in the Neotropical region and to prevalence of blood parasites in the avifauna of other major land masses.

Animals↗

Prevalence of blood protozoan parasites of avian species in Nsukka area of Anambra State, Nigeria.

A total of 165 avian species (110 chickens, 15 turkeys, 12 ducks, 10 each of geese and guinea fowls, and 8 pigeons) were examined for blood protozoan parasites. Blood samples were collected from the wing veins and smears with Giemsa stain. Plasmodium spp. were found in 2 chickens (1.6%) and 7 turkeys (46.6%). 5 turkeys were clinical cases. 3 (37.5%) of the pigeons were positive for Haemoproteus spp. No blood parasites were found in geese, ducks, and guinea fowls. The results show that avian malaria can constitute a health problem in poultry, especially turkeys, in Nigeria. The avian species may act as a reservoir host for human malaria parasites.

Animals↗

In vitro effects of fetal bovine serum and glucose on multiplication of Cryptobia salmositica.

Cryptobia salmositica multiplied rapidly at 10 C in a minimum essential medium (containing 1.0 mg glucose/ml, Hanks' salts and L-glutamine) supplemented with heat-inactivated fetal bovine serum (FBS) and HEPES buffer (25 mM). The multiplication rate of C. salmositica was related to the amount of FBS; the peak number (approximately 9 x 10(6) parasites/ml) was attained in about 6 wk when the medium contained 25% final concentration of FBS. Glucose utilization was related to the number of parasites; the maximum utilization was reached before peak numbers. Formation of rosette colonies was correlated with multiplication rate and numbers of parasites in cultures. Degenerate round forms found in old cultures probably were caused by the accumulation of metabolic wastes in the medium.

Animals↗

Early schizonts of Leucocytozoon caulleryi.

Sporozoites of Leucocytozoon caulleryi were inoculated intravenously into 26-day-old specific pathogen-free chickens. Six days after inoculation, early schizonts were detected in lung, spleen, and thymus. They existed separately and were spherical or ovoid, 30-35 microns in diameter, and had well defined walls.

Animals↗

Neospora caninum (Apicomplexa) in an aborted equine fetus.

Tachyzoites of Neospora caninum were found in sections of lung of an equine fetus aborted 2 mo before term. Individual tachyzoites were approximately 3-5 x 2-3 microns, divided by endodyogeny, and stained positively with anti-N. caninum serum but not with anti-Toxoplasma gondii serum. Toxoplasma gondii antibody was not found in the mare's serum. This is the first report of N. caninum in a horse and indicates that N. caninum can be transmitted transplacentally in equids.

Abortion, Veterinary↗

Repeated transplacental transmission of Neospora caninum in dogs.

Four litters of German Shorthaired Pointers from one owner developed a toxoplasmosis-like illness. According to the records, 29 of 39 dogs had hind limb paralysis. Six dogs from 2 litters were necropsied and had generalized encephalomyelitis. Tachyzoites and tissue cysts of Neospora caninum were found in the brain and spinal cord of each dog. Lesions were found in the eyes, extraocular muscles, or both in all of the dogs, and N caninum was detected microscopically in the eyes (retina and choroid in 1 dog), extraocular muscles, or both in 5 of the 6 dogs. Ocular lesions consisted of focal retinitis, choroiditis, mild nonspecific iridocyclitis, and myositis of extraocular muscles. Organisms stained with anti-N caninum serum, but not with anti-Toxoplasma gondii serum in an immunohistochemical test, except in 1 dog. In one dog, aged thick-walled N caninum tissue cysts reacted mildly with anti-T gondii serum.

Animals↗

Hexamitiasis and an emaciation syndrome in pheasant poults: clinical aspects and differential diagnosis.

Clinical hexamitiasis was recorded in pheasant poults between six and 12 weeks old, after placing the birds into release pens, and was characterised by reduced appetite, lethargy and emaciation. Post mortem the carcases were dehydrated. The presence in the lumen of the gut of characteristic motile organisms which could often be found several hours after death, provided a good clinical diagnosis. An emaciation syndrome, clinically similar but not associated with hexamitiasis or other pathogens also occurs in poults. It is characterised by extreme emaciation, largely confined to the pectoral muscles, and dehydration although the birds continue to eat and drink; the cause is unknown. Both hexamitiasis and the emaciation syndrome can cause high morbidity and mortality.

Animals↗