Are pikas exposed to and affected by selenium deficiency?

Regional extirpations of pikas (Ochatona princeps) within the last few decades have been attributed to global warming. Other recent global alterations such as increased nitrogen (N) deposition and associated selenium (Se) deficiency may further stress pika populations. In 2003 and 2004, we live-trapped pikas from three populations in Wyoming and measured Se values in their hair. We also sampled hair and liver from museum specimens collected throughout the Northern Rocky Mountains in 1987 and 1988. Our results suggest that liver and hair values were related, and that pika hair reflected the Se concentrations of the geologic parent materials. We determined that animals residing in several remote areas in the Rocky Mountain region could be Se deficient and that increase in N deposition correlated with an increase rather than a decrease in Se values in pika hair. In addition, we found no relation between Se contents in hair and body condition index, suggesting that low Se levels may not have negative effects on individual pikas. Whether Se levels influence reproductive success of pikas is unknown and should be the focus of future studies.

The effect of state legislation on eye donation.

PURPOSE: Pennsylvania Act 102 implemented in March 1995 required all acute care hospitals in Pennsylvania to routinely refer all deaths to the Organ Procurement Organization for determination of suitability for organ/tissue donation. This study analyzed the effect of the law on eye donation. METHODS: Retrospective analysis of the total number of referrals and the actual number of eye donations from 62 hospitals in Pennsylvania to the Lions Eye Bank of Delaware Valley was performed for the years 1993 to 1998. Information gathered included donor's age, gender, race, cause of death, referring institution, and result of referral. RESULTS: From 1993 to 1998, the total numbers of referrals were 988, 1,647, 8,101, 21,123, 21,783, and 22,987, and the numbers of donors were 570, 574, 660, 644, 594, and 568, respectively. The increase in the number of donors after implementation of the law was not commensurate with the number of referrals. This was caused by a disproportionate increase in the number of referrals older than 70 years of age (from a mean of 33% to 52%), which exceeded the donor age limit of 69 years, and also to a lower family consent rate (from a mean of 48% to 24%). CONCLUSIONS: Well-designed state legislation with proper implementation greatly increased hospital referrals for eye donation. However, there was only a small increase in the number of eye donors because many of the referrals were beyond the acceptable upper age limit for eye donation. A small increase in the donor age limit would increase the number of eye donations without having to expand the potential donor pool. Education of the public may help to improve the family consent rate.

Synonymy of Eimeria larimerensis with Eimeria lateralis.

Oocysts of Eimeria lateralis were isolated from feces of Spermophilus richardsonii and compared to published descriptions of E. lateralis and Eimeria larimerensis from other spermophiline rodent hosts. A comparison from other spermophiline rodent hosts. A comparison of these 2 eimerian species, combined with an examination of host specificity of spermophiline eimerians and host and parasite distributions, suggests that E. larimerensis is synonymous with E. lateralis.

Eimerian guilds (Apicomplexa: Eimeriidae) in Richardson's (Spermophilus richardsonii) and Wyoming (Spermophilus elegans) ground squirrels.

Feces of Richardson's ground squirrels (Spermophilus richardsonii) were examined to determine occurrence and prevalence of eimerian species and to compare guilds in these hosts to previously described guilds from Wyoming ground squirrels (Spermophilus elegans). Six species of Eimeria were collected from 100 Richardson's ground squirrels: Eimeria beecheyi (36% infected); Eimeria bilamellata (13%); Eimeria callospermophili-Eimeria morainensis complex (41%); Eimeria lateralis (6%); and Eimeria spermophili (9%). The species composition and prevalences were essentially identical in the 2 congeneric hosts. Three species were consistently more (> 30%) and 3 were consistently less (< 20%) prevalent in both host species. Furthermore, in both squirrel species the rare species were more prevalent in juveniles. Eimerian guilds such as these may be common to many species of ground-dwelling sciurid squirrels. The report of E. beecheyi in Richardson's ground squirrel constitutes a new host record for this species.

Effects of eimerian (Apicomplexa: Eimeriidae) infections on nutrient assimilation in the Wyoming ground squirrel.

Effects of infection with mixed species of Eimeria (E. callospermophili, E. morainensis, and E. beecheyi) on the digestive physiology of Wyoming ground squirrels (Spermophilus elegans) are described. Infected and uninfected squirrels were administered arginine and methionine in saturated glucose solution. Blood was drawn at time 0 and 30 min postadministration. Significant differences were not found between infected and uninfected squirrels in plasma glucose, arginine, or methionine assimilation. In a second experiment, infected and uninfected squirrels were fed a food slurry of known caloric value. All feces were collected for 24 hr postfeeding. Differences were not detected in fecal caloric content or digestive efficiency. These results in conjunction with results reported in the literature suggest a reassessment of the "parasitic" nature of these squirrel symbionts. We propose that associations of some Eimeria species and hosts that evolve under natural conditions are examples of parasite-host interactions that often evolve toward commensalism.

Coccidian assemblages in the Wyoming ground squirrel, Spermophilus elegans elegans.

One thousand nineteen Wyoming ground squirrels (Spermophilus elegans elegans) from 4 populations in southern Wyoming were examined for intestinal parasites. The most prevalent parasites were 6 species of coccidia: Eimeria beecheyi, Eimeria bilamellata, Eimeria callospermophili, Eimeria larimerensis, Eimeria morainensis, and Eimeria spermophili. Most ground squirrels harbored 2 or more species. This eimerian assemblage was present across populations and over years. Differences in the prevalence of infection were not found among host age classes or between sexes. The presence or absence of helminths was independent of the presence and absence of Eimeria. A log-linear model to test the independence of the distribution of Eimeria spp. among hosts revealed 3 significant positive associations, for E. bilamellata and E. beecheyi, E. morainesis and E. callospermophili, and E. larimerensis and E. bilamellata.

Analysis of the feline immune response to human myelin-associated glycoprotein.

Elucidation of the pathogenesis of demyelinating peripheral neuropathy associated with myelin-associated glycoprotein (MAG) binding IgM paraproteins requires an in vivo animal model of the syndrome. Multiple immunizations of cats with MAG in Freund's adjuvant did not produce an antibody response but four immunizations with MAG-iscom (Morein, B. et al. (1984) Nature, 308: 457-460) did induce IgM antibodies which bound to human MAG and cat peripheral nerve myelin. Despite the presence of antibody for a 13-month period, no neuropathy developed. At necropsy, the peripheral nerves were ultrastructurally normal and no antibody was detectable in the endoneurium. A competitive ELISA indicated that the cat and human IgM antibodies recognized different epitopes.

Cushion plants as islands.

The acarine fauna of two abundant species of cushion plant on the high, short-grass prairie of S.E. Wyoming were used to test The MacArthur-Wilson Theory of Island Biogeography. Multiple regression analysis using area, distance and percent moisture as independent variables and number of mite species and number of mite individuals were run for the two sampling dates. Results showed area alone to be consistently and highly correlated (r=0.84-0.94) with both species and individuals for one cushion species. The slopes of the species-area and individuals-area curves are among the highest recorded and were significantly higher on the second sampling date. Selective seasonal changes in the fauna were shown by increases both in numbers of species and individuals, mainly on larger cushions, for the later sampling period. It is hypothesized that seasonal changes are due to an increase in the number of predator species in response to an increase in the number of prey items. The slopes of the species-area curves are compared with those in the literature and it is argued that slope values are more dependent upon the taxonomic group being studied than on whether the island is insular or oceanic. Finally, we suggest that The MacArthur-Wilson Theory is not applicable to islands which 1) exhibit continuous growth, 2) lack a discrete species source, and 3) are relatively transitory.