VIRUS NEUTRALIZING ANTIBODY FOLLOWING ORAL RABIES VACCINATION OF RACCOONS (PROCYON LOTOR) ON SUBURBAN LONG ISLAND, NEW YORK, USA.

Vaccine-laden baits were distributed to interrupt and halt raccoon (Procyon lotor) rabies transmission in suburban Nassau and Suffolk counties on Long Island, New York, US. Fishmeal polymer baits containing the RABORAL V-RG® vaccine were deployed with helicopters, bait stations, and vehicles at a target density of 250 baits/km2 during annual September campaigns (2006-10). Semiannual campaigns (500 baits/km2) were also initiated in a portion of the treatment zone (2007-09) in response to a persistent focus of rabid raccoons. The last enzootic case was reported in January 2009. The final vaccination campaign was completed in 2010. The raccoon variant of rabies virus is no longer circulating in Nassau or Suffolk counties. Significantly greater probabilities of raccoon seroconversion were observed in helicopter-deployed bait zones. The lowest probabilities of seroconversion were identified in vehicle and bait station-deployment bait zones, with a marginal advantage associated with bait-station deployment. Seroconversion was negatively associated with developed, medium-intensity areas and increasing human population density. Significantly higher rabies virus neutralizing antibody endpoint titrations were detected in helicopter and bait station-deployment zones.

Serosurvey of Coyotes (Canis latrans), Foxes (Vulpes vulpes, Urocyon cinereoargenteus), and Raccoons (Procyon lotor) for Exposure to Influenza a Viruses in the USA.

We tested coyote (Canis latrans), fox (Urocyon cinereoargenteus, Vulpes vulpes), and raccoon (Procyon lotor) sera for influenza A virus (IAV) exposure. We found 2/139 samples (1 coyote, 1 raccoon) had IAV antibodies and hemagglutination inhibition assays revealed the antibodies to the 2009/2010 H1N1 human pandemic virus or to the 2007 human seasonal H1N1 virus.

Evaluation of Trapper-Collected Nobuto Filter-Paper Blood Samples for Distemper and Parvovirus Antibody Detection in Coyotes (Canis latrans) and Raccoons (Procyon lotor).

Blood samples are often collected from free-ranging wildlife for antibody detection. However, filter-paper (FP) strips are more cost efficient and easy to collect and store. We evaluated trapper-collected FP strips and body-cavity blood for canine distemper (CDV) and parvovirus (CPV-2) antibody detection in raccoons (Procyon lotor) and coyotes (Canis latrans). From 2008 to 2010, licensed trappers near Madison and Milwaukee, Wisconsin, US collected paired samples from harvested animals. Canine distemper antibodies were detected using virus neutralization and parvovirus antibodies were detected using hemagglutination inhibition. Titers ≥ 1:32 for CDV and ≥ 1:25 for CPV-2 were considered evidence of exposure. Using Cohen's kappa test of agreement, FP strip titers agreed with sera for CDV in coyotes (n = 28, K = 0.772) and raccoons (n = 29, K = 0.858) and for CPV-2 in coyotes (n = 40, K = 0.775) and raccoons (n = 70, K = 0.646). However, raccoons determined to be exposed to CPV-2 from sera were unexposed by FP strips in 35% of the samples. Titer results may be affected by quality and volume of blood samples, interval between collection and processing, small sample sizes, and diagnostic testing procedures. Filter-paper strips can be useful for detecting CDV and CPV-2 exposure in coyotes and raccoons with correct field sample collection and appropriate diagnostic testing procedures.

Species-specific differences in the accumulation features of organohalogen contaminants and their metabolites in the blood of Japanese terrestrial mammals.

Residue levels and patterns of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), their hydroxylated metabolites (OH-PCBs, OH-PBDEs), and methoxylated PBDEs (MeO-PBDEs) in the blood of various terrestrial mammals in Japan, including cats, raccoon dogs, dogs, masked palm civets, foxes, raccoons, badgers, and mongooses were determined. Tri- through penta-chlorinated OH-PCBs were predominant in cat blood, whereas hexa- through octa-chlorinated OH-PCBs were found in other species. High proportion of BDE209 was found in all species, suggesting exposure to municipal waste and soil containing higher levels of deca-BDE products. 6OH-/MeO-BDE47 and 2'OH-/MeO-BDE68 were dominant in all terrestrial mammals. This is first report on the detection of OH-/MeO-PBDEs in the blood of terrestrial mammals. High concentrations of OH-/MeO-PBDEs were found in cats, suggesting the intake of these compounds from seafood. Cats exhibited higher accumulation and specific patterns of OH-PCBs, OH-PBDEs, and MeO-PBDEs, they may be at a high risk from these metabolites.

Oral rabies vaccination of raccoons and striped skunks with ONRAB® baits: multiple factors influence field immunogenicity.

Multiple control methods have been used in North America to manage the spread of rabies caused by the raccoon (Procyon lotor) rabies virus variant (RRVV). Recently, oral vaccination with ONRAB(®) vaccine baits, which contain an adenovirus rabies glycoprotein recombinant, has been made available as an additional tool for rabies control. Our objectives were to estimate rabies antibody prevalence in wild-caught raccoons and striped skunks (Mephitis mephitis), and identify factors influencing the probability of being antibody positive at the individual level in these species, following oral rabies vaccination (ORV) campaigns in which ONRAB was distributed aerially in 2007-2009 in southern Québec, Canada. Following the aerial distribution of 43-155 ONRAB baits/km(2), the annual percentages of antibody-positive raccoons and skunks varied between 35% and 56% and 11% and 17%, respectively. In raccoons, the probability of being antibody positive was positively associated with age and density of ONRAB distributed, and influenced by the number of previous ORV campaigns conducted. Conversely, this probability was negatively associated with estimated abundance of raccoons in the trapping cell and proportion of residential areas near the raccoon capture location. None of the variables examined explained variation in the probability of being antibody positive in skunks. Our results indicate that the ONRAB density applied during ORV campaigns should be adjusted to account for variations in raccoon population density and presence of residential areas to increase the likelihood of creating an effective immunological barrier against RRVV. The high percentage of juvenile raccoons (annual mean =45 ± 3 [SE]%) and skunks (66 ± 2%) captured during post-ORV monitoring suggests that ORV campaigns should be conducted at least annually to account for the recruitment of naïve individuals into the populations. In Québec, the increasing use of ONRAB coincided with the elimination of rabies caused by RRVV. Nonetheless, our results indicate that improvements to this vaccine bait and/or the distribution techniques are required to increase its efficacy, especially in striped skunks.

Immune response and protection in raccoons (Procyon lotor) following consumption of baits containing ONRAB®, a human adenovirus rabies glycoprotein recombinant vaccine.

We investigated the immune response and protection conferred in raccoons (Procyon lotor) following consumption of ONRAB(®) oral rabies vaccine baits. Forty-two wild-caught, captive raccoons were each offered an ONRAB vaccine bait; 21 controls received no vaccine baits. Blood samples collected from all raccoons before treatment, and each week posttreatment for 16 wk, were assessed for the presence of rabies virus antibody. In the bait group, an individual was considered to have responded to vaccination if serum samples from three or more consecutive weeks were antibody-positive. Using this criterion, 77% (20/26) of raccoons that consumed ONRAB baits with no observed vaccine spillage (full dose) demonstrated a humoral immune response. In the group that received a partial dose (0.05-0.90 mL vaccine recovered), 50% (8/16) of raccoons responded to vaccination. Regardless of the vaccine dose received, among the 28 raccoons that responded to vaccination 18 had antibody initially detectable at week 2 and 22 remained antibody-positive for at least 10 consecutive weeks. Kinetics of the humoral immune response suggest that the best time to conduct postbaiting surveillance for evidence of vaccination would be 6-13 wk following bait deployment, with the highest antibody prevalence expected between weeks 8-10. A sub-sample of 29 raccoons (20 ONRAB, 9 controls) was challenged with raccoon rabies virus variant 350 days posttreatment. Eight of nine controls (89%) developed rabies whereas 15/20 vaccinates (75%) survived. Survival following rabies challenge was significantly higher in raccoons presented ONRAB vaccine baits.

Seasonal changes in spermatogenesis and peripheral testosterone concentration in raccoons (Procyon lotor) in Hokkaido.

Feral raccoons (Procyon lotor) have been increasing in number since 1979 and are currently subject to pest control in Hokkaido. One of the reasons for the increase in numbers is thought to be the high reproductive potential of raccoons, but little is known about their reproduction. The main aim of this study was to clarify seasonal changes in spermatogenesis and peripheral testosterone concentration of raccoons in Hokkaido. In the present study, external characteristics and histology of the testis and epididymis and the plasma testosterone concentration were investigated in 68 feral, male raccoons culled for pest control and once a month in one live, captive male. The feral males exhibited seasonal changes in spermatogenesis, showing active spermatogenesis in autumn, winter and spring (October-June) with noted spermatogenesis and inactive spermatogenesis in summer (July-September) with lower mean levels of spermatozoa in the cauda epididymis. Even in the inactive period, spermatozoa were observed in about half of the individuals (14/26); therefore, individuals producing spermatozoa existed every month throughout the year. Testosterone concentrations were significantly high in the winter mating season. In the captive male, the testosterone concentrations were low from June to August, and spermatozoa could not be observed from July to September. These results suggest that raccoons exhibit seasonality of reproduction, but the time and duration of spermatogenetic decline varies widely among individuals. This individual variation in the inactive period is a feature of male raccoon reproduction and is unique among seasonally breeding mammals.

Comparing ONRAB® AND RABORAL V-RG® oral rabies vaccine field performance in raccoons and striped skunks, New Brunswick, Canada, and Maine, USA.

Control of rabies in mesocarnivore reservoirs through oral rabies vaccination (ORV) requires an effective vaccine bait. Oral rabies vaccine performance in the field may be affected by a variety of factors, including vaccine bait density and distribution pattern, habitat, target species population density, and the availability of competing foods. A field study in which these covariates were restricted as much as possible was conducted along the international border of the state of Maine (ME), USA, and the province of New Brunswick (NB), Canada, to compare the performance of two oral rabies vaccines in raccoons (Procyon lotor) and striped skunks (Mephitis mephitis). RABORAL V-RG(®) (vaccinia-rabies glycoprotein recombinant oral vaccine in fishmeal-coated sachet) or ONRAB(®) (adenovirus-rabies glycoprotein recombinant oral vaccine in Ultralite bait matrix) were distributed in ME and NB, respectively, by fixed-wing aircraft at a density of 75 baits/km(2) along parallel flight lines spaced 1.0 km apart. Sera were collected from live-trapped raccoons and skunks 5-7 wk post-ORV and assayed to determine antibody prevalence in each area. Duplicate serum samples were provided blind to two different laboratories for analyses by rabies virus serum neutralization assays (at both laboratories) and a competitive enzyme-linked immunosorbent assay (at one laboratory). There was no significant difference in the proportion of antibody-positive animals determined by the three serologic methods, nor was there a significant difference between ONRAB and RABORAL V-RG in the proportion of antibody-positive striped skunks observed post-ORV. In contrast, the proportion of antibody-positive raccoons was significantly higher in the ONRAB- versus the RABORAL V-RG-baited areas (74% vs. 30%; χ(2)=89.977, df=5, P<0.0001). These data support that ONRAB may serve as an effective tool for raccoon rabies control.

Immunogenicity and efficacy of two rabies vaccines in wild-caught, captive raccoons.

The immunogenicity and efficacy of two rabies vaccines in wild-caught, captive raccoons (Procyon lotor) were investigated. Raccoons were fed Ontario Slim (OS) baits containing a recombinant vaccinia virus-rabies glycoprotein (VRG) oral rabies vaccine, or they were given an intramuscular (IM) injection of IMRAB(®) 3 rabies vaccine. Blood samples collected before treatment and from weeks 1 to 16 posttreatment were assessed for the presence of rabies virus antibody (RVA). There were significantly more positive responders in the group that received an IM injection of IMRAB 3 (18/27) than in the group that consumed VRG in OS baits (VRG-OS; 4/ 26). There were no significant associations among age, sex, and seroconversion. Of those animals that mounted a humoral immune response to vaccination, RVA was first detected between weeks 1 and 5, with the majority of initial seroconversions detectable at week 2. A subsample of 50 raccoons (19 VRG-OS, 18 IMRAB 3, and 13 controls) from the longitudinal serology study was challenged with live raccoon variant rabies virus 442 days after initial treatment. There were significantly more survivors in the group that received IMRAB 3 (13/18) than in the VRG-OS (5/19) or control (2/13) groups. All 15 raccoons that demonstrated a serologic response survived challenge regardless of treatment. Of the 35 raccoons with no detectable serologic response, 30 (86%) succumbed to rabies virus infection (14/15 VRG-OS, 5/7 IMRAB 3, and 11/13 controls).

Tick-borne disease agents in various wildlife from Mississippi.

Because tick-borne diseases are becoming increasingly important throughout the world, monitoring their causative agents in wildlife may serve as a useful indicator of potential human exposure. We assessed the presence of known and putative zoonotic, tick-borne agents in four wildlife species in Mississippi. Animals were tested for exposure to or infection with Ehrlichia chaffeensis, Ehrlichia ewingii, Borrelia lonestari, Rickettsia spp., Anaplasma phagocytophilum, and Francisella tularensis. Whole blood and serum were tested from white-tailed deer (WTD; Odocoileus virginianus) and feral swine (Sus scrofa); serum was tested from raccoons (Procyon lotor) and opossums (Didelphis virginiana). We used polymerase chain reaction to detect all agents in blood, whereas an indirect fluorescent antibody assay was used to detect antibodies to E. chaffeensis, B. lonestari, and Rickettsia parkeri (spotted fever group rickettsiae) antigens in serum. Molecular evidence of infection with E. chaffeensis, B. lonestari, and An. phagocytophilum was detected only in WTD. Antibodies to E. chaffeensis antigen were detected in 43.9% of WTD, 32.8% of swine, 42.1% of raccoons, and 15.8% of opossums. Serologic evidence of exposure to B. lonestari antigen was found in 19.3% of WTD, 6.9% of swine, and 5.3% of raccoons, but not in opossums. Interestingly, the percent of animals with antibodies reactive to spotted fever group rickettsiae (R. parkeri antigen) was highest in raccoons (73.7%) and opossums (57.9%). These results support the role of WTD as reservoirs for E. chaffeensis, B. lonestari, and An. phagocytophilum, as well as provide additional evidence for exposure of raccoons and opossums to E. chaffeensis. Finally, we provide new data that feral swine may have antibodies to these agents. Thus, in general, these four wildlife species are exposed to tick-borne disease agents in Mississippi, suggesting that ticks carry and have the potential to transmit the agents to humans in the state.

Genetic variability and viral seroconversion in an outcrossing vertebrate population.

Inverse correlations between genetic variability and parasitism are important concerns for conservation biologists. We examined correlations between neutral genetic variability and the presence of antibodies to canine distemper virus (CDV) and feline parvovirus (FPV) in a free-ranging population of raccoons. Over 3 years there was a strong relationship between age and seroprevalence rates. Most young animals were seronegative to CDV and FPV, but the oldest age class was greater than 80 per cent seropositive to both viruses. CDV-seropositive animals had greater heterozygosity and lower measures of inbreeding compared with CDV-seronegative animals. This relationship was strongest among the youngest animals and did not occur during a 1 year CDV epidemic. In contrast, FPV-seropositive animals only had significantly lower measures of inbreeding in 1 year, perhaps because FPV-associated mortality is relatively low or primarily occurs among very young individuals that were under-represented in our sampling. These results suggest that even in large outcrossing populations, animals with lower heterozygosity and higher measures of inbreeding are less likely to successfully mount an immune response when challenged by highly pathogenic parasites.

Antigenic characterization of Trypanosoma evansi using sera from experimentally and naturally infected bovines, equines, dogs, and coatis.

The present research investigated the presence of T. evansi antibodies in animals from the subregion of Nhecolandia, in the Pantanal Sul-mato-grossense, by means of an enzyme linked immunosorbent assay (ELISA) and indirect immunofluorescence antibody test (IFAT), and the pattern of polypeptide recognition by sera from experimentally and naturally infected hosts using Western blotting. Serum samples were obtained from bovines (n = 102), horses (n = 98), and dogs (n = 55), and from 32 free-ranging coatis (Nasua nasua). None of the bovines were found positive, while sera from 16 dogs (29%) and 23 horses (23.4%) were positive by ELISA. Sera from 8 coatis (25%) were found positive using IFAT. Western blotting revealed major polypeptides of T. evansi with molecular weight ranging from 74 to 38 kDa. The polypeptides of 66, 48-46, and 38 kDa were identified by sera from experimentally infected bovines, donkeys, dogs, and coatis. The 48-46 and 38 kDa bands were mainly recognized in chronic phase of infection. The antigen with apparent molecular weight of 66 kDa, revealed by antibodies from all experimental animals, was also recognized in sera of horses and dogs from the Pantanal. The 48-46 kDa polypeptide was identified by antibodies from all naturally infected animals and must be further evaluated for use in specific diagnosis of T. evansi infection.

Antigenic characterization of Trypanosoma evansi using sera from experimentally and naturally infected bovines, equines, dogs, and coatis / Caracterização antigênica do Trypanosoma evansi usando soros de bovinos, equinos, cães e quatis experimentalmente e naturalmente infectados

The present research investigated the presence of T. evansi antibodies in animals from the subregion of Nhecolandia, in the Pantanal Sul-mato-grossense, by means of an enzyme linked immunosorbent assay (ELISA) and indirect immunofluorescence antibody test (IFAT), and the pattern of polypeptide recognition by sera from experimentally and naturally infected hosts using Western blotting. Serum samples were obtained from bovines (n = 102), horses (n = 98), and dogs (n = 55), and from 32 free-ranging coatis (Nasua nasua). None of the bovines were found positive, while sera from 16 dogs (29 percent) and 23 horses (23.4 percent) were positive by ELISA. Sera from 8 coatis (25 percent) were found positive using IFAT. Western blotting revealed major polypeptides of T. evansi with molecular weight ranging from 74 to 38 kDa. The polypeptides of 66, 48-46, and 38 kDa were identified by sera from experimentally infected bovines, donkeys, dogs, and coatis. The 48-46 and 38 kDa bands were mainly recognized in chronic phase of infection. The antigen with apparent molecular weight of 66 kDa, revealed by antibodies from all experimental animals, was also recognized in sera of horses and dogs from the Pantanal. The 48-46 kDa polypeptide was identified by antibodies from all naturally infected animals and must be further evaluated for use in specific diagnosis of T. evansi infection.

O trabalho de pesquisa investigou a presença de anticorpos anti- T. evansi em animais da sub-região da Nhecolândia, no Pantanal sul-mato-grossense, pelo ensaio imunoenzimático (ELISA) e a reação de imunofluorescência indireta (RIFI). O reconhecimento de polipeptídeos de T. evansi foi realizado pela técnica de "Western blotting", utilizando soros de animais experimentalmente e naturalmente infectados. As amostras de soro foram obtidas de bovinos (n = 102), cavalos (n = 98) e cães (n = 55) e de 32 quatis de vida livre (Nasua nasua) do pantanal mato-grossense. Todos os soros dos bovinos foram negativos, enquanto soros de 16 cães (29 por cento) e 23 cavalos (23,4 por cento) foram positivos pelo ELISA. Soros de oito quatis (25 por cento) foram positivos pela RIFI. Pelo "Western-blotting" foi possível revelar polipeptídeos de T. evansi, com peso molecular variando de 74 a 38 kDa. Os polipeptídeos de 66, 48-46 e 38 kDa foram identificados por soros de bovinos, cavalos, cães e quatis experimentalmente infectados. As bandas de 48-46 e 38 kDa foram reconhecidas principalmente na fase crônica da infecção. O antígeno com peso molecular aparente de 66 kDa, revelado por anticorpos de todos os animais experimentais, também foi reconhecido por soros de cavalos e cães do Pantanal. O polipeptídeo de 48-46 kDa foi identificado por anticorpos de todos os animais naturalmente infectados, devendo ser avaliado para o diagnóstico específico da infecção pelo T. evansi.

Antibody responses of raccoons naturally exposed to influenza A virus.

An investigation was performed to describe the responses of naturally acquired antibodies to influenza A virus in raccoons (Procyon lotor) over time. Seven wild raccoons, some of which had been exposed to multiple subtypes of influenza A virus, were held in captivity for 279 days, and serum samples were collected on 10 occasions during this interval. Serum samples from 9 of 10 bleeding occasions were tested using an epitope-blocking enzyme-linked immunosorbent assay for the presence of antibodies to influenza A virus. Although titer declines were noted in most animals over time, all animals maintained detectable antibodies for the duration of the study. These data indicate that naturally acquired antibodies to influenza A virus can remain detectable in raccoons for many months, with the actual duration presumably being much longer because all animals had been exposed to influenza A virus before this study commenced. This information is important to surveillance programs because the duration of naturally acquired antibodies to influenza A virus in wildlife populations is largely unknown.

Detection of antibody to canine distemper virus in wild raccoons (Procyon lotor) in Japan.

Canine distemper virus (CDV) causes a lethal disease among members of the Carnivora. To clarify the distribution of CDV in wild animals, we examined 106 raccoon sera collected from two prefectures in Japan, Hyogo and Osaka, from 2005 to 2007. Among them, 34 raccoons (32.1%) possessed a virus-neutralizing (VN) antibody to KDK-1 strain (genotype Asia-1). There was no significant difference in seroprevalence of CDV regardless of places, gender, and body weights. In Hyogo, a geometric mean of VN titers to KDK-1 was significantly higher than that to Onderstepoort (vaccine strain), indicating that KDK-1-like CDV different from vaccine strain might have spread among raccoon population in Hyogo. In conclusion, CDV is epidemic among feral raccoons in Japan, suggesting that CDV might have been spreading among Japanese wild animals.

Culex pipiens (Diptera: Culicidae): a bridge vector of West Nile virus to humans.

Host-feeding patterns of Culex pipiens L. collected in southwest suburban Chicago in 2005 were studied using polymerase chain reaction (PCR) and DNA sequencing techniques. Culex spp. mosquitoes, most identified to Cx. pipiens and the remainder to Cx. restuans by PCR, had fed on 18 avian species, most commonly American robin (Turdus migratorious), house sparrow (Passer domesticus), and mourning dove (Zenaida macroura). Additional blood meals were derived from four mammal species, primarily humans and raccoons (Procyon lotor). During a West Nile virus (WNV) epidemic in 2005, West Nile virus (WNV) RNA was detected in heads and thoraces of five Cx. pipiens (n = 335, 1.5%) using quantitative PCR. The hosts of these virus-infected, blood-fed mosquitoes included two American robins, one house sparrow, and one human. This is the first report of a WNV-infected Cx. pipiens mosquito collected during an epidemic of WNV that was found to have bitten a human. These results fulfill a criterion for incrimination of Cx. pipiens as a bridge vector.

Monkeypox zoonotic associations: insights from laboratory evaluation of animals associated with the multi-state US outbreak.

At the onset of the 2003 US monkeypox outbreak, virologic data were unavailable regarding which animal species were involved with virus importation and/or subsequent transmission to humans and whether there was a risk for establishment of zoonotic monkeypox in North America. Similarly, it was unclear which specimens would be best for virus testing. Monkeypox DNA was detected in at least 33 animals, and virus was cultured from 22. Virus-positive animals included three African species associated with the importation event (giant pouched rats, Cricetomys spp.; rope squirrels, Funisciuris sp.; and dormice, Graphiuris sp.). Virologic evidence from North American prairie dogs (Cynomys sp.) was concordant with their suspected roles as vectors for human monkeypox. Multiple tissues were found suitable for DNA detection and/or virus isolation. These data extend the potential host range for monkeypox virus infection and supports concern regarding the potential for establishment in novel reservoir species and ecosystems.

Raccoons and skunks as sentinels for enzootic tularemia.

We analyzed sera from diverse mammals of Martha's Vineyard, Massachusetts, for evidence of Francisella tularensis exposure. Skunks and raccoons were frequently seroreactive, whereas white-footed mice, cottontail rabbits, deer, rats, and dogs were not. Tularemia surveillance may be facilitated by focusing on skunks and raccoons.

Seasonal changes in serum leptin of the feral raccoon (Procyon lotor) determined by canine-leptin-specific ELISA.

Several reports have been published on blood leptin concentrations in feral animals, including members of the Carnivora, using a commercially available multi-species radioimmunoassay (RIA) kit with anti-human leptin antibody. However, we observed weak immunoreactivity between recombinant canine leptin and anti-human leptin antibody, suggesting a limitation in the applicability of the RIA kit for leptin assays in Carnivora species. We tested the applicability of RIA and sandwich enzyme-linked immunosorbent assay (ELISA) with anti-canine leptin antibody to assay blood leptin in the dog (Canis familiaris) and the raccoon (Procyon lotor). When RIA was used for recombinant canine leptin and dog sera, values were much lower than those determined by ELISA at higher concentrations (>10 ng/ml), while rather higher at lower concentrations (<2 ng/ml). A similar discrepancy between the two methods was found for serum leptin concentrations in raccoons. Clear seasonal variations were observed by ELISA, but not by RIA, with high values in autumn (3.46+/-0.45 ng/ml) and low values in spring and summer (0.71+/-0.07 ng/ml). Serum leptin concentrations in raccoons correlated positively with their body weight (r=0.753) and body mass index (r=0.755), corroborating our previous findings of a strong positive correlation between serum leptin concentrations and body fat content in dogs. Thus, the canine leptin ELISA is useful for assays of dog and raccoon leptin, and blood leptin is a good marker of nutritional condition in the species of Carnivora assayed in this study.

Monitoring perchlorate exposure and thyroid hormone status among raccoons inhabiting a perchlorate-contaminated site.

Perchlorate is a water soluble anion that is readily accumulated in vegetation. It inhibits uptake of iodide into thyroid gland tissue, thereby reducing production of thyroid hormones. Potential raccoon food items including berries, fish, and vegetation collected at a contaminated site contained quantifiable concentrations of perchlorate as determined by ion chromatography. Therefore, we monitored resident raccoons for exposure to perchlorate by examining plasma perchlorate and thyroid hormone concentrations. Resulting analytical data failed to demonstrate perchlorate exposure among raccoons that likely consumed food items collected along perchlorate-contaminated water bodies. There were no correlations between triiodothyronine or thyroxine and thyroid stimulating hormone concentrations, but triiodothyronine concentrations in raccoon plasma were significantly higher in 2000 than in 2001 (p = 0.0081). These data suggest that natural attenuation and remedial efforts initiated in January of 2001 may have reduced perchlorate exposure among raccoons inhabiting this site from 2000 to 2001. Temporal, spatial, and analytical factors limited our ability to quantify exposure among raccoons, however, our data do not indicate that raccoons currently inhabiting this site are at risk for significant exposure to perchlorate and subsequent effects.