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Biomedical subjects

A N Hamir

Publications and source records attributed to A N Hamir.

At least 55 records · Page 3Linked to original sources
PubMed1999

Cerebral larva migrans in a raccoon (Procyon lotor).

During 1997, gross and histopathologic examinations were performed on an adult female raccoon (Procyon lotor) that was live-trapped in Corvallis, Oregon. Multifocal eosinophilic granulomas indicative of neural and visceral larva migrans were observed. However, within these granulomas, the presence of parasitic larva was seen only in the cerebrum. Morphologic characteristics indicated that the nematode was an ascarid larva. However, it was smaller than the larva of Baylisascaris sp. This appears to be the first documented case of cerebral larva migrans in a raccoon.

Animals↗
PubMed1999

Prevalence of Sarcocystis kirkpatricki Sarcocysts in the central nervous system and striated muscles of raccoons from the Eastern United States.

A retrospective survey of 760 raccoons (Procyon lotor) revealed 9 animals with sarcocysts of Sarcocystis kirkpatricki in their brains. Six of the raccoons also had the organisms in their skeletal muscles, and 1 had them in the heart muscle. No age or gender predisposition was seen. Seven of the raccoons had concurrent viral diseases (canine distemper or rabies), suggesting that concurrent viral infections in raccoons may facilitate infection of brain tissue with S. kirkpatricki.

Animals↗
PubMed1999

A retrospective histopathological survey of capillariasis in raccoons (Procyon lotor) from Oregon.

A 2-yr retrospective survey (1995-1998) of 63 adult raccoons (Procyon lotor) from Oregon, northwestern United States, was conducted by histopathological examination of various tissues. An overall prevalence of capillariasis was recorded in 52% of the raccoons. Highest prevalence of nematodes (29/30, 97.7%) was present in the anal sacs, where variable numbers of nematodes, their ova, and extensive diffuse inflammatory cellular infiltrate were evident. Lesser numbers of nematodes were also seen in the mucosa of the anterior alimentary tract (mouth 2/63, tongue 10/62, esophagus 2/63) and in the urinary bladder (7/63). However, at these sites, there was a paucity of inflammatory infiltrate. The findings of this study indicate that capillariasis of the anal sacs is commonly seen in free-ranging raccoons in Oregon, and the infection is essentially subclinical because only 1 case of anal sac impaction has been reported. Measurements of the nematode and their ova from the anal sacs indicate that it is most likely a new capillariid species, which to date has not been fully described in raccoons. It is speculated that the high prevalence of anal sac infection by a Capillaria sp. in Oregon raccoons may also be true for raccoons in other parts of North America and in parts of Europe and Asia where this species has been introduced.

Animals↗
PubMed1998

Neospora caninum-associated equine protozoal myeloencephalitis.

Equine protozoal myeloencephalitis (EPM) was clinically diagnosed in a 20-year-old horse with severe ataxia. The cerebrospinal fluid was positive for Sarcocystis neurona antibodies by western blot. The horse was administered corticosteroids to facilitate in vitro culture of S. neurona from its spinal cord following necropsy. Microscopic lesions of EPM were present in the brain and in the spinal cord, including multifocal inflammatory cellular infiltrates and several large groups of protozoa. Immunohistochemical, and light and electron microscopic examinations revealed that the protozoa were Neospora caninum and not S. neurona. The protozoa divided by endodyogeny, tachyzoites had rhoptries, and organisms reacted specifically to N. caninum antibodies. Veterinarians should be aware of increasing diagnosis of N. caninum as another etiological agent responsible for the lesions of EPM.

Animals↗
PubMed1998

First North American field release of a vaccinia-rabies glycoprotein recombinant virus.

Following nearly 10 yr of extensive laboratory evaluation, a vaccinia-rabies glycoprotein (V-RG) vaccine was the first recombinant virus to undergo limited North American field release on 20 August 1990. The free-ranging raccoon population on Parramore Island (Virginia, USA) was exposed to a high density (10 baits/ha) of vaccine-laden baits distributed on a 300 ha vaccination area. An annual total of 887 raccoons were live-trapped for sedation, physical examination and blood collection for rabies antibody determination; there was no evidence of adverse effects or lesions due to the vaccine. Age and sex distributions, mean body weights, and live-capture histories of raccoons from the vaccination and non-baited control areas were compared. There were no statistically significant differences in survivorship between the baited and non-baited areas, nor between rabies antibody-positive and antibody-negative raccoons from the vaccination area. There was no trend in field mortality that suggested an association with either tetracycline or sulfadimethoxine, used as biomakers, or with vaccine contact determined by antibody status. No gross or histopathologic lesions due to the vaccine were demonstrated among a subsample of live-trapped raccoons collected for gross necropsy, biomarker analysis, histopathologic examination, and V-RG virus isolation attempts. Recovery of V-RG virus was limited to the tonsils of two biomarker-positive, clinically healthy raccoons collected from the vaccination area for postmortem examination on days 2 and 4 following bait distribution. These data reinforce the extensive body of safety data on the V-RG virus and extend it to include field evaluation where vaccine is offered free-choice in abundance, in baits designed to attract free-ranging raccoons, in a relatively simple ecosystem.

Administration, Oral↗
PubMed1998

A retrospective histopathological survey of capillariasis in raccoons from the eastern United States.

A 7-yr retrospective survey (1986-1993) of 193 raccoons (Procyon lotor) from 4 different geographic locations (South Carolina, Virginia, and 2 sites in Pennsylvania) in the eastern United States was conducted by histopathological examination of various tissues. Lesions indicative of capillariasis were observed in raccoons at all locations. An overall prevalence of 45% was recorded. Highest prevalence of nematodes in tissues (71%) was seen in the rural Pennsylvania site. Nematodes were confined to the mucosa of the anterior alimentary tract (mouth, tongue, esophagus) or urinary system (bladder, urethra) without significant inflammation except for a single raccoon in which Capillaria sp. were present in the tracheal mucosa and within the subjacent lamina propria, with moderate inflammatory cellular infiltrate.

Animals↗
PubMed1998

Cryptosporidiosis in a bat (Eptesicus fuscus).

Cryptosporidial infection was diagnosed histologically in the small intestine of a big brown bat (Eptesicus fuscus) from Oregon. This is the first report of cryptosporidiosis in a bat.

Animals↗
PubMed1997

Neuronal vacuolation in raccoons (Procyon lotor).

Microscopic vacuolar changes in neuronal perikaryon are described in two free-ranging raccoons (Procyon lotor) from different geographic locations in the United States. Both animals were negative for rabies and scrapie-associated antigens. Microscopically, lesions were not seen in the neuropil. Neuronal vacuolations have previously been documented in brains of normal animals and in diseases such as rabies and prion-associated encephalopathies. Although experimental transmission of a spongiform mink encephalopathy has been documented in raccoons, a naturally occurring spongiform encephalopathy has not been described in this species. The presence of neuronal vacuolations in the raccoons is novel and requires further investigation to elucidate the mechanism of this phenomenon.

Animals↗
PubMed1997

Capillariasis in the trachea of a raccoon.

Cross-sections of nematodes were seen in histologic sections of trachea from a raccoon (Procyon lotor) collected in Virginia (USA); they occupied epithelium and contained unembryonated, bioperculated eggs characteristic of the genus Capillaria (= Eucoleus). A mild inflammatory cell infiltrate in the lamina propria subjacent to the nematode was the only apparent host response. This is the first report of capillariasis in the trachea of raccoons.

Animals↗