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Biomedical subjects

H E Jordan

Publications and source records attributed to H E Jordan.

At least 19 recordsLinked to original sources

The pig as a potential organ donor for man. A study of potentially transferable disease from donor pig to recipient man.

Ten pigs, reared in an unmodified laboratory animal house environment, have been investigated to ascertain the incidence of diseases or disorders, including infection, neoplasia, or metabolic abnormalities, that might preclude the transplantation of major organs from the pig to man. Noninvasive studies were performed in the second month of life (study 1) and repeated after an interval that varied between 3 and 5 1/2 months (study 2). Necropsy was then performed as a means of assessing the accuracy of the 2 screening examinations. A total of 150 tests were performed on each pig. At both studies the feces contained cysts and/or trophozoites of several parasites, all of which were considered commensals. No other organisms potentially infective for man were identified either at study or at necropsy. Neither congenital anomalies nor malignant neoplasia was found at necropsy. However, in 2 pigs a vasculitis of uncertain etiology was present in the kidneys on microscopic examination, and in one of these the same condition affected the heart. This pathology was suspected neither from the screening examinations nor from the macroscopic appearance of these organs. Biopsy and microscopic examination would therefore appear to be essential before any organ is transplanted into a human.

Animal Feed↗

Endoparasitism in dogs: 21,583 cases (1981-1990).

Prevalence of endoparasites (particularly ascarids) in dogs examined at the Oklahoma State University veterinary medical teaching hospital during 1981 to 1990 was determined by fecal and blood examinations. Approximately 1,250 fecal and 900 blood specimens were examined each year. In 1981, 55% of dogs harbored 1 or more parasites, compared with 36% in 1990. Percentages of all endoparasitic species decreased, except Giardia spp, which increased. The greatest decrease in prevalence was for Ancylostoma spp, which changed from 39% in 1981 to 15% in 1990. Prevalence of Toxocara spp and Trichuris spp also significantly decreased from 1981 (8% and 12%, respectively) through 1990 (4% and 9%, respectively). Although there appeared to be a downward trend in these ascarid infections, considerable environmental contamination probably existed and continues to exist because of high fecundity and long survival of eggs in the environment. Prevalence of Dipetalonema spp had a downward trend from a high of 4% in 1981 to < 1% by 1991. Prevalence of Dirofilaria spp decreased from 12% in 1982 to 6% in 1985, but by 1990, it was 11%.

Animals↗

Developmental biology and migration of Strongyloides ratti in the rat.

Most recent authors suggest that larvae of the threadworm, Strongyloides ratti, migrate from a cutaneous infection site to the small intestine via the naso-frontal region of the head. However, the proportion of larvae that successfully reach the intestine having followed this pathway had not been determined. Using compartmental analysis we have obtained a comprehensive quantitative description of larval migration during a primary infection of rats with S. ratti. Mean residence times in organs through which larvae migrate were calculated and the proportion of the larvae arriving in the small intestine via the head was estimated as 0.5-0.86, depending on the mathematical model used to generate the estimate. With 50% or more of successful larvae using this pathway it is now reasonable to recognize the "head route" as an important migratory pathway for larvae traveling to their intestinal predilection site. During the first 12 hr in the host, larvae were difficult to recover from the skin and subjacent muscles of the infection site. Apparently, upon invading a host, many larvae enter a quiescent phase during which Baermannization, an active recovery technique, fails to recover them. Infections were short-lived, with the daily finite mortality rate for adult worms attaining 50-80% on day 16 of infection.

Animals↗

Potential for the spread of Fasciola hepatica in cattle in Oklahoma.

In 29 central and western Oklahoma counties, 42 ranches were investigated for indigenous Fasciola hepatica infections and their suitability for the transmission of liver fluke. A 10-year retrospective study of Oklahoma cattle based on samples submitted to the Oklahoma Animal Disease Diagnostic Laboratory also was done. Indigenous fascioliasis was found in cattle in 12 counties (9 central and western counties identified in the combined field and retrospective studies and 3 additional eastern counties identified on the basis of the retrospective study). Factors essential for survival of free-living stages of F hepatica and for snail species necessary for propagation of the fluke existed in much of Oklahoma. Snails capable of serving as intermediate hosts for transmission of the fluke reportedly have been found in 41 of the 77 Oklahoma counties. Lymnaeid snails were detected in 4 counties in the field study.

Animals↗

An overview of serological tests currently available for laboratory diagnosis of parasitic infections.

Current methods and commercial test systems for the diagnosis of parasitic infections in both animals and humans are reviewed. Lists of test kits and their manufacturers are provided along with ordering information: the only commercially available test kits are for the diagnosis of toxoplasmosis in humans or animals and dirofilariasis (heartworm) in dogs. A partial list of diagnostic laboratories and the parasite tests they perform is also provided. Complete lists of diagnostic tests that could be obtained in the private sector are not available but would be useful. Two microfluorometric solid-phase assay systems are reviewed, and adaptations to custom assays for several kinds of parasites are briefly described. User problems in performing tests and interpreting results are stressed with emphasis placed on diagnosis of dirofilariasis in dogs. False-positive serology in dogs without heartworms and negative antibody responses in micro-filariae-positive animals are discussed with respect to proper interpretation of results.

Anaplasmosis↗

The importance of endoparasite counts at necropsy.

In a 2-year study of 49 Oklahoma cattle with a typical history of clinical endoparasitism, 12 animals had Ostertagia only, and Ostertagia was the predominant endoparasite in 21. Only 1 animal had a pure Haemonchus population. Though primary endoparasitism was diagnosed antemortem in 32 animals, postmortem worm counts confirmed the diagnosis in only 19. Worm counts documented inapparent disease in 8 animals. In 21 cases of suspected of toxicosis, 12 animals had endoparasitism none was poisoned.

Animals↗

Prevalence of gastrointestinal parasitism in Oklahoma swine.

The prevalence of swine gastrointestinal parasites was determined from all listed large swine operations (28) and a geographically representative sample (70) of the population of small hog farm operations in Oklahoma. Fecal samples (n = 975) were collected from 98 farms. From the 98 farms, parasites were recovered in pig feces as follows: Ascaris, 53.0%, strongyles, 53.1%, Trichuris, 35.7%, spirurids, 6.1%, Strongyloides, 19.4%, coccidia, 57.1%, and Balantidium, 55.1%. A higher percentage (16.5%) of hogs maintained on cement floors were positive for Ascaris than were those on either dirt lots (11.9%) or slatted floors (9.9%), but pigs on dirt lots were more often positive with a higher percentage of coccidia (21.0%) than those on either cement or slatted floors (8.5% and 6.0%, respectively). Prevalence of Trichuris was essentially the same (6.8% to 11.3%) in hogs from all 3 management practices.

Animals↗

Cerebrospinal parelaphostronglylosis in llamas.

Four of 11 llamas (Lama guanicoe) from a ranch near Houston, Texas developed clinical signs of a neurologic disease. Tissues from 2 of the 4 llamas were submitted for microscopic examination. Lesions in the central nervous system of both llamas appeared to have been caused by a migrating parasite. An adult nematode having morphologic features of the meningeal worm (Parelaphostrongylus tenuis) was found in the brain of one llama. The findings suggest that the neurologic disease in the llamas were caused by P. tenuis.

Animals↗

Influence of Ostertagia ostertagi and Cooperia infections on the energetic efficiency of steers fed a concentrate ration.

Studies on effects of subclinical parasitism (low worm burden) in full-fed and maintenance-fed steers indicated that over a short interval low worm burdens do not have a statistically significant effect on the efficiency of energy utilization. In full-fed steers, energy retention tended to be higher in steers with lower worm burdens (mean 95.8 Ostertagia, 12.5 Cooperia) than in those with higher worm burdens (mean 677.5 Ostertagia, 201.8 Cooperia). Maintenance-fed steers generally had larger numbers of Ostertagia ostertagi and Cooperia spp than did the full-fed steers.

Animal Feed↗