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Biomedical subjects

W R Davidson

Publications and source records attributed to W R Davidson.

100 records · Page 6Linked to original sources

Dirofilariaformia pulmoni sp. n. (Nematoda: Onchocercidae) from the eastern gray squirrel (Sciurus carolinensis Gmelin).

Dirofilariaeformia pulmoni sp. n. from the eastern gray squirrel (Sciurus carolinensis Gmelin) is differentiated from other species of the genus by its smaller body size, shorter spicules, arrangement of caudal papillae, and morphology of microfilariae. Adult filarids were found in the pulmonary artery and its branches, and the microfilariae occurred in the blood. A large antemortem thrombus that occluded approximately two-thirds of the lumen of the artery was associated with infection in one squirrel.

Animals↗

The spectrum of left ventricular-right atrial communications in the adult: essentials of echocardiographic assessment.

Left ventricular-right atrial communication may be a congenital defect or can result from trauma, endocarditis, or valve replacement. Traditionally the preoperative diagnosis of this entity was made during cardiac catheterization, but recent advances in echocardiography, particularly color Doppler imaging, have greatly facilitated the noninvasive diagnosis of left ventricular-right atrial communication. We present four cases of left ventricular-right atrial communication, each identified by two-dimensional and color Doppler imaging. One case is a congenital defect, two were identified years after cardiac surgery, and one presents as an unusual complication of myocardial infarction. Optimal views for identifying this defect are discussed along with clues to quantifying its hemodynamic significance.

Adult↗

Health status of northern bobwhite quail (Colinus virginianus) in eastern Kansas.

The health status of wild northern bobwhite quail (Colinus virginianus) from Lyon County, Kansas, was evaluated by conducting comprehensive health assessments on 25 birds. Gross lesions indicative of avian pox, ulcerative enteritis, and quail bronchitis were not present. Serologic tests for antibodies to Salmonella pullorum, Salmonella gallinarum, Pasteurella multocida, Mycoplasma gallisepticum, Mycoplasma synoviae, and avian adenoviruses were all negative. Intestinal coccidia (Eimeria spp.) were found in 36% of the birds. Only three species of helminth parasites were found: Dispharynx nasuta in two birds, Cyrnea colini in one bird, and larval Physaloptera sp. in four birds. Arthropod parasites (ticks, lice, mites, and/or chiggers) were present on 96% of the birds examined. Compared with wild bobwhite populations in the southeastern United States, the diversity, prevalence, and intensities of microbial and parasitic agents were low.

Animals↗

Failure of Heterakis bonasae to transmit Histomonas meleagridis.

Studies were conducted to determine whether Heterakis bonasae eggs from bobwhite quail infected with Histomonas meleagridis would transmit histomoniasis to turkeys. Fifteen helminth-free bobwhites were inoculated per os with embryonated H. bonasae eggs. Each bobwhite was then infected with H. meleagridis via rectal inoculation. Bobwhites that developed cecal lesions rarely retained mature H. bonasae. H. bonasae eggs recovered from bobwhites exposed to or known to have concurrent H. meleagridis infections were inoculated per os to eleven helminth-free turkeys. None of the turkeys developed H. meleagridis infections.

Animals↗

Deletrocephalus dimidiatus infestation in an adult rhea (Pterocnemia pennata).

Infection with the nematode Deletrocephalus dimidiatus was found in the distal small and proximal large intestines of a 30-month-old female rhea that had died after a prolonged illness. Numerous strongyle-like eggs were found on fecal flotation. Possible treatments include fenbendazole (60 ppm in water) and ivermectin (200 mg/kg). Preventive measures such as artificial incubation, segregation of chicks from adults, and placing chicks in uncontaminated environments may help slow or stop the transmission of the parasite.

Animals↗