Biomedical subjects
Publications and source records attributed to D E Snyder.
A case report is presented of an Angle Class I dental malocclusion, significant bimaxillary dentoalveolar protrusion, anterior open bite, and spacing of the maxillary and mandibular incisors. [This case was presented to the American Board of Orthodontics in partial fulfillment of the requirements for the certification process conducted by the Board.]
A single juvenile male raccoon (Procyon lotor) was found naturally infected with Dirofilaria immitis. Two immature female worms were found in the heart of this raccoon at necropsy. Lesions attributable to the presence of these parasites were not found. Histopathologic examination of various tissues did not reveal any microfilariae. The raccoon may serve as an aberrant definitive host for this parasite, however, patent infections have not been reported.
Numerous Phagicola angrense were associated with enteritis in a single male juvenile raccoon (Procyon lotor) live-trapped on Parramore Island, Virginia (USA). The raccoon was weak, ataxic and had melenic soft feces. The carcass was emaciated, pale and had ascites. Mesenteric vessels appeared prominent and the stomach and the intestines contained fetid bloody material. The small intestinal mucosa contained three locally extensive sites of necrosis. Histopathologically, there were numerous small digeneans both attached to the mucosa and free within the lumen. Digeneans were usually found deep within the crypts where the epithelium was markedly attenuated and devoid of epithelial cells at the point of parasite attachment. In the lamina propria there were areas of acute hemorrhage and infiltration with plasma cells and eosinophils. This appears to be the first record of severe enteritis in the raccoon caused by this digenean.
Histologic examination of the tongue of one juvenile male raccoon demonstrated the presence of adults and unembryonated eggs of the nematode Capillaria procyonis within parasite-induced tunnels in the stratified squamous epithelium. There was no inflammatory infiltrate within the epithelium or the subjacent lamina propria. The shape of tunnels approximated that of the resident nematodes and were lined by flattened and attenuated epithelial cells. Therefore, the site of infection of C. procyonis in the raccoon includes the oral, lingual and pharyngeal epithelium in addition to the esophagus.
Prior to a limited field application of an orally-administered vaccinia-rabies glycoprotein (V-RG) recombinant virus vaccine for wildlife, background data were obtained for the proposed site on Parramore Island, Virginia (USA). Mammalian target and nontarget species, potentially at risk for exposure to vaccine were inventoried. Placebo baiting trials with a fishmeal polymer bait resulted in high bait disturbance (88 to 100%), primarily by raccoons (Procyon lotor), with infrequent visitation and no evidence of bait consumption by deer (Odocoileus virginianus), small mammals or avian species. Definitive bait acceptance rates by raccoons (indicative of bait ingestion) were difficult to accurately determine based exclusively on premolar and vibrissae samples collected antemortem from live-trapped raccoons for tetracycline and rhodamine B biomarker analyses, respectively. Bait acceptance rate was more accurately determined during a pilot baiting trial conducted on North Island, South Carolina, when mandibles (postmortem samples) were examined for tetracycline incorporation. Parasitologic findings in raccoons on Parramore Island included Hepatozoan procyonis, Phagicola angrense and Physaloptera rara and a variety of incidental microscopic lesions, and provided baseline pathological data for comparison subsequent to V-RG vaccine application. A population density estimate of one raccoon/2.7 ha was calculated using mark-recapture data for comparison after vaccine deployment. Limited reproductive data, including estimates of pregnancy rates by palpation, the number of live kits/litter live-trapped with previously pregnant raccoons or observed in the dens of radio-collared raccoons, was gathered to assess the effect of proposed oral vaccination with V-RG vaccine. Home ranges were assessed by radio-telemetry of 15 raccoons; all radio-collared raccoons currently reside on Parramore Island.(ABSTRACT TRUNCATED AT 250 WORDS)
A single adult male river otter (Lutra canadensis) from Louisiana was found naturally infected with Dirofilaria immitis. One adult male nematode was found in the heart; lesions attributable to the presence of the parasite were not found. This is the first report of D. immitis in the river otter in North America.
A case report is presented of a Class II, Division 1 malocclusion with severe overjet and deep overbite with crowding and irregularities of the anterior teeth. The case was treated according to the standards of the American Board of Orthodontics.
A case report is presented of a Class II, Division 2 malocclusion in the mixed dentition with excess overjet, deep overbite, and mandibular arch-length deficiency. The case was treated to the standards of the American Board of Orthodontics.
Fecal samples from 100 wild raccoons were examined for the presence of oocysts of Cryptosporidium parvum using a commercially available indirect immunofluorescent detection procedure. Thirteen (13%) of the samples were positive for oocysts. All positive samples were from juvenile raccoons. Over 61% of the infected samples contained moderate to large numbers of oocysts. Raccoons may serve as potential reservoirs for transmission of C. parvum.
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The gastrointestinal tracts of 310 steel-trapped or hunter shot Illinois raccoons (Procyon lotor) were collected in November and December 1979 and 1980 and examined for the presence of Baylisascaris procyonis (Nematoda) in order to determine the prevalence and intensity of this ascarid and to note any differences with respect to host age and sex. The raccoons were classified as either juveniles (animals less than 1 yr old) or adults. The prevalence for all the raccoons examined was 81.9% and is the highest reported in the United States when compared to other moderate to large samples. Juvenile raccoons had a significantly higher (P less than 0.0005) prevalence (93.5%) and mean intensity (62.4) than adults (55.3%; 11.8). Male raccoons had a significantly higher (P less than 0.025) prevalence (87.6%) than females (76.4%). Adult males had a significantly higher (P less than 0.05) prevalence (66.7%) than adult females (44.9%). In the other comparisons, no significant differences (P less than 0.05) in either prevalence or intensity were found. Since juveniles are more heavily infected than adults, they most likely pose a greater threat to other animals and humans as a potential cause of visceral larva migrans. It is advisable that all young raccoons kept as pets or in captivity be systematically and routinely treated with an appropriate anthelminthic to remove adult B. procyonis from the intestine.
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The effects of salinity, pH, and temperature on the longevity and hatchability of miracidia of Philophthalmus megalurus and P. gralli were determined. Miracidia of both species are able to hatch and survive at saline concentrations much above physiological levels, although these processes are reduced in 2.0--2.4% saline and completely inhibited at 2.6%. The greatest hatching rates for both species were found near neutrality (pH 6--8) but some miracidia hatched at the extreme pH levels of 3 and 12. Philophthalmus megalurus miracidia exhibited longer half-lives under acid conditions (pH 2--6) than P. gralli miracidia; conversely, P. gralli miracidia showed longer half-lives in alkaline conditions (pH 8--11). Hatching and longevity were much greater below room temperature (5--20 C) than above (30--50 C) for miracidia of both species. Temperatures above 50 C proved lethal for eyefluke eggs. Except in acid pH, P. gralli miracidia showed longer half-lives than miracidia of P. megalurus. Comparison to studies on schistosomes revealed that the inhibitory effects of physiological saline and host body temperature on the hatching process of schistosome eggs does not occur in these 2 species of eyeflukes.
Except for the inconvenience of liquifying the material in some other place, the described setup is almost as convenient as a regular hydrocolloid unit. The chief disadvantage is that the small tanks will hold only about three regular tubes of material at a time.
The purpose of this study was to determine in the rice rat model whether a relationship exists between the severity of periodontal disease and the presence of severity of pulpal lesions. The results indicated that, even in the presence of severe loss of alveolar bone, extending close to the root apices, there were no detectable changes in the pulpal tissues as compared to the pulps of teeth in which there was no loss of alveolar bone. The scarcity of accessory pulp canals in the rice rat may be related to our findings.