| cotton rats and other small mammals as hosts for immature dermacentor variabilis (acari: ixodidae) in central oklahoma. | eight species of small mammals were evaluated as potential hosts for american dog ticks, dermacentor variabilis (say), in an upland, tallgrass prairie study site in central oklahoma. only hispid cotton rats, sigmodon hispidus, and deer mice, peromyscus maniculatus, were found to be important hosts for immature d. variabilis. although d. varibilis larvae and nymphs frequently infested both cotton rats and deer mice, cotton rats were the most important host species for both immature stages in the ... | 1992 | 1404263 |
| influence of habitat modification on the community of gastrointestinal helminths of cotton rats. | dynamics of communities of gastrointestinal helminths of cotton rats (sigmodon hispidus) were monitored in response to five experimental brush management treatments using herbicide applications with and without prescribed burning on the cross timbers experimental range in payne county, oklahoma (usa). a total of 113 adult cotton rats (68 male and 45 female) was collected from experimental pastures in winter and summer 1986 resulting in the recovery of five species of helminths: longistriata adun ... | 1991 | 1758023 |
| strongyloidiasis in cotton rats (sigmodon hispidus) from central oklahoma. | thirty-one of 40 cotton rats (sigmodon hispidus) collected from central oklahoma were infected with strongyloides sp. (78% prevalence). larvae of strongyloides sp. (rhabditiform or filariform) were not demonstrable in intestinal contents and scrapings. female nematodes recovered from intestinal contents and scrapings had morphological similarities with strongyloides sigmodontis. cotton rats infected with strongyloides sp. were indistinguishable clinically from non-infected hosts. infected animal ... | 1990 | 2201800 |
| fluorosis in a wild cotton rat (sigmodon hispidus) population inhabiting a petrochemical waste site. | we have developed an in situ mammalian model for evaluating environmental contamination using wild cotton rats. in a series of experiments, 200 male cotton rats were captured during 4 collection periods (spring 1991 = 35; fall 1991 = 60; spring 1992 = 53; fall 1992 = 52). a total of 103 of these cotton rats were captured from control sites, and the remaining 97 were captured from an abandoned oil refinery. all sites were located in the vicinity of cyril, oklahoma. there were alterations in the i ... | 1994 | 7732274 |
| environmental, age, and sex effects on cotton rat (sigmodon hispidus) hematology. | we determined the effects of sex, age, and environment (inbred, captive-wild, and wild animals) on selected blood parameters of the cotton rat (sigmodon hispidus) in central oklahoma (usa) from 1990 to 1994. male and female cotton rats had similar blood profiles. age-related differences were confined to differential white blood cell counts where adults possessed greater numbers of neutrophils and lower numbers of lymphocytes compared to juveniles. environment had a strong influence on many hemat ... | 1996 | 8722287 |
| fluorosis risks to resident hispid cotton rats on land-treatment facilities for petrochemical wastes. | land-treatment of petroleum wastes is a widely used industrial practice, yet there has been no comprehensive evaluation of the long-term risks to human or terrestrial ecosystems from such practices. we evaluated cotton rat (sigmodon hispidus) populations on three sites in oklahoma (usa) that historically used land-treatment for disposal of various petroleum wastes (july 1995-march 1997). average concentrations of fluoride in soil from these sites ranged from 878 to 4317 mg/kg. a census of reside ... | 2000 | 11085424 |
| immunotoxicity risks associated with land-treatment of petrochemical wastes revealed using an in situ rodent model. | land-treatment of petrochemical wastes is a widely used method to dispose of hazardous and non-hazardous waste by biodegradation. however, no comprehensive assessment of the impact of such disposal techniques on terrestrial ecosystems has been conducted. despite the presence of suspected immunotoxicants in the soil, wild rodents frequently reside on these waste sites after closure or abandonment. we explored the seasonal sensitivity of the immune system of the hispid cotton rat (sigmodon hispidu ... | 2001 | 11202656 |
| widespread risks of dental fluorosis in cotton rats (sigmodon hispidus) residing on petrochemical waste sites. | fluoride has been identified as a ubiquitous contaminant of soils where petrochemical wastes have been disposed. the purpose of this study was to assess how widespread toxicity risks are to resident vertebrates from chronic exposure to fluoride in the soil of petrochemical-contaminated waste sites. in total, 573 wild cotton rats (sigmodon hispidus) were examined. the rats that were seasonally collected from 12 contaminated and 12 ecologically matched reference sites across oklahoma over a 3-yr p ... | 2001 | 11209820 |
| evaluation of myelotoxicity in cotton rats (sigmodon hispidus) exposed to environmental contaminants. ii. myelotoxicity associated with petroleum industrial wastes. | various chemical mixtures exist in soil contaminated with petrochemical wastes, yet no comprehensive assessment of their impact on terrestrial ecosystems has been conducted. the purpose of this study was to evaluate hematotoxicity risks to wild populations of cotton rats (sigmodon hispidus) residing in habitats previously contaminated by petroleum industrial wastes. resident cotton rats were monitored on nine contaminated sites and nine ecologically matched reference sites in oklahoma. the possi ... | 2001 | 11209824 |
| ecotoxicological risks associated with land treatment of petrochemical wastes. i. residual soil contamination and bioaccumulation by cotton rats (sigmodon hispidus). | petrochemical waste contains both organic and inorganic contaminants that can pollute soil and may pose significant ecological risks to wildlife. petrochemical waste typically is disposed of in land treatment units, which are widespread throughout oklahoma and the united states. few studies have been conducted evaluating possible toxicity risks to terrestrial organisms residing on these units. in this study, the extent of soil contamination with fluoride (f), metals, and organic hydrocarbons, th ... | 2003 | 12554539 |
| ecotoxicological risks associated with land treatment of petrochemical wastes. iii. immune function and hematology of cotton rats. | landfarming is a widely used method of treating petrochemical waste through microbial bio-degradation. the effects of residual petrochemical contamination on wildlife, especially terrestrial mammals, are poorly understood. the effects of contaminants on the immune system and hematology of cotton rats (sigmodon hispidus) living on five abandoned petrochemical landfarms (units 1-5) in oklahoma were studied. cotton rats were sampled seasonally (summer and winter) from each landfarm and from five ec ... | 2003 | 12554541 |
| immune function and hematology of male cotton rats (sigmodon hispidus) in response to food supplementation and methionine. | we examined effects of supplementation of food quantity and quality (=enhanced methionine) on hematologic and immunologic parameters of wild, but enclosed, adult male cotton rats (sigmodon hispidus) in north-central oklahoma. sheet metal enclosures were stocked with a high density of wild-caught cotton rats (160 animals/ha) and randomly assigned a treatment of no supplementation, mixed-ration supplementation or methionine-enhanced supplementation. aside from small increases in counts of red bloo ... | 2003 | 14613786 |
| population dynamics of cotton rats (sigmodon hispidus) inhabiting abandoned petroleum landfarms in oklahoma, usa. | previous work by our group has shown bioaccumulation of contaminants and alterations in the immune system of hispid cotton rats (sigmodon hispidus) inhabiting petrochemical waste sites (landfarms). we studied populations of cotton rats inhabiting petrochemical landfarms or uncontaminated reference sites. cotton rat populations inhabiting abandoned landfarms experienced reduced summer population densities and lower mean monthly survival, with maximum densities 65% that of populations inhabiting n ... | 2006 | 16374662 |
| small mammals as indicators of short-term and long-term disturbance in mixed prairie. | disturbance by military maneuvers over short and long time scales may have differential effects on grassland communities. we assessed small mammals as indicators of disturbance by military maneuvers in a mixed prairie in southern oklahoma usa. we examined sites on two soil series, foard and lawton, across a gradient of disturbance intensity. a manova showed that abundance of small mammals was associated (p = 0.03) with short-term (cover of vehicle tracks) disturbance but was not associated (p = ... | 2008 | 17458511 |
| field survey of rodents for hepatozoon infections in an endemic focus of american canine hepatozoonosis. | eighteen of 31 (58%) cotton rats (sigmodon hispidus) and 8 of 24 (33.3%) white-footed mice (peromyscus leucopus) that were wild-trapped from 4 american canine hepatozoonosis endemic sites in oklahoma were infected with hepatozoon species. the predilection organ for merogony of the hepatozoon species in cotton rats was the liver. meronts were not detected in any of the white-footed mice. a 488 bp dna fragment that includes a variable region of the 18s rrna hepatozoon gene amplified from blood or ... | 2007 | 17942230 |
| light and transmission electron microscopic characteristics of a novel hepatozoon spp. in naturally infected cotton rats (sigmodon hispidus). | a novel species of hepatozoon was recently reported in cotton rats (sigmodon hispidus) collected from an area of oklahoma where american canine hepatozoonosis is endemic. in this study, the various stages of merogony of the parasite were characterized by light and electron microscopy. meronts occurred within parasitophorous vacuoles in hepatocytes and ranged from mononucleated spherical forms to large, mature forms in vacuoles that contained approximately 50 peripherally arranged merozoites. dev ... | 2009 | 19629526 |
| alternate pathway of infection with hepatozoon americanum and the epidemiologic importance of predation. | the range of american canine hepatozoonosis (ach) is expanding from the southern usa northward. transmission of hepatozoon americanum occurs by ingestion of infected gulf coast ticks, amblyomma maculatum. the source of the protozoan for the tick remains undetermined; infected dogs are unusual hosts for the tick. | 2009 | 19709355 |
| geographic range expansion for rat lungworm in north america. | using quantitative pcr analysis and dna sequencing, we provide evidence for the presence of rat lungworm (angiostrongylus cantonensis) in oklahoma, usa, and identified a potentially novel rat host (sigmodon hispidus). our results indicate a geographic range expansion for this medically and ecologically relevant parasite in north america. | 2015 | 26079818 |