Michael J. Dreslik

Chrysosporium sp. Infection in Eastern Massasauga Rattlesnakes

To the Editor: During 2008, the ninth year of a long-term biologic monitoring program, 3 eastern massasauga rattlesnakes (Sistrurus catenatus catenatus) with severe facial swelling and disfiguration died within 3 weeks after discovery near Carlyle, Illinois, USA. In spring 2010, a similar syndrome was diagnosed in a fourth massasauga; this snake continues to be treated with thermal and nutritional support and antifungal therapy. A keratinophilic fungal infection caused by Chrysosporium sp. was diagnosed after physical examination, histopathologic analysis, and PCR in all 4 snakes. The prevalence of clinical signs consistent with Chrysosporium sp. infection during 2000–2007 was 0.0%, and prevalence of Chrysosporium sp.–associated disease was 4.4% (95% confidence interval [CI] 1.1%–13.2%) for 2008 and 1.8% (95% CI 0.0%–11.1%) for 2010.

Reptile road mortality around an oasis in the Illinois corn desert with emphasis on the endangered eastern Massasauga

Abstract Roads have numerous negative ecological effects on terrestrial fauna, and vehicular mortality can have significant demographic consequences for some species. We studied road mortality of reptiles around Carlyle Lake, Clinton County, Illinois, USA, from April 2000 through November 2002, to assess the impact of vehicular traffic and identify influential factors. Carlyle Lake, a popular tourism/recreation area, is situated in a larger agricultural landscape and is home to the largest Illinois population of the endangered Eastern Massasauga (Sistrurus catenatus). We documented 321 cases of reptile road mortality (84 individuals of six turtle species and 237 individuals of nine snake species) while driving our approx. 46 km study route roundtrip daily. Turtle road mortality was highest in May and June, and positively associated with precipitation and minimum daily temperature. Colubrid snake road mortality was highest in April and October, and positively associated with minimum daily temperature. We recorded 42 cases of road mortality of S. catenatus with the highest number occurring from mid-August to mid-September. Road mortality in S. catenatus was biased toward adult males, which show an increase in movement in August, coinciding with the peak of the mating season and a period of high tourist visitation. The traffic intensity on a road segment did not significantly affect the level of road mortality, but segments through high quality habitats had higher levels of mortality than segments through lower quality habitats. Based on our study on the ecology of S. catenatus, we make recommendations to reduce road mortality that should aid in the conservation of the Carlyle Lake population.

Ongoing Health Assessment and Prevalence of Chrysosporium in the Eastern Massasauga (Sistrurus catenatus catenatus)

With the current rate of declines in global biodiversity, it is apparent that wildlife diseases are serving as additional threats to population declines and potentially species extinctions. Free-ranging Eastern Massasaugas (Sistrurus catenatus catenatus) have been reported susceptible to numerous health threats, one of which is a fatal fungal dermatitis. In response to the occurrence of the fungal dermatitis, a health survey and disease investigation was conducted on Eastern Massasaugas near Carlyle, Illinois in 2011. We captured 38 Eastern Massasaugas from March to April 2011. Polymerase chain reaction assays were performed from swabs collected from the faces of 34 snakes. We obtained hematologic data for 31 individuals, plasma biochemical data for 24, and toxicological data for 18. There was no evidence of Chrysosporium in any of the samples. Hematologic and plasma biochemistry parameters were consistent with previous health studies in the Carlyle population. Elemental toxicologic investigation of the plasma indicated variable levels of lead, copper, selenium, strontium, tin, iron, and zinc.

Structure and Composition of a Southern Illinois Freshwater Turtle Assemblage

Abstract We report on a six-year study (1994–1999) of a diverse turtle assemblage in Gallatin County, IL. Ten species of freshwater turtles representing four families were recorded. Species richness increased as a function of trap hours, with 3000 trap hours required to capture all species. The greatest density and biomass was for Trachemys scripta. Pseudemys concinna ranked second in density, but Chelydra serpentina ranked second highest in biomass. Females comprised the majority of the biomass in emydids, biomass ratios were even in Sternotherus odoratus, and males comprised the majority of the biomass in C. serpentina. Relative abundance did not significantly differ among the six years, although some uncommon species were not captured in all years.

Measuring Agreement and Discord among Hemagglutination Inhibition Assays Against Different Ophidian Paramyxovirus Strains in the Eastern Massasauga (Sistrurus catenatus catenatus)

Abstract At present, the hemagglutination inhibition (HI) assay is the sole commercially available serologic method available to detect exposure to ophidian paramyxovirus (OPMV) in snakes. During 2006, 26 eastern massasaugas (Sistrurus catenatus catenatus) were collected, and blood was sampled to determine their OPMV status. Samples from each snake were divided into 3 aliquots and tested by using commercially available HI assays against the 4 OPMV isolates used in the 3 laboratories that offer the service. All snakes were tested for antibodies by using HI assays against the green tree python (GTP), San Lucan rattlesnake (SLR), and Aruba Island rattlesnake (AIR) isolates. Twenty-five snakes were tested for antibodies against the western diamondback rattlesnake (WDR) isolate. All samples tested against the GTP and SLR were positive (26/26), whereas 56% (14/25) of the WDR assays were positive, and none (0/ 26) of the AIR assays yielded a positive result. There was 100% agreement between the GTP and SLR assays, and complete disagreement between the SLR and AIR, as well as the GTP and AIR assays. Kappa statistics for the GTP– WDR, SLR–WDR, GTP–AIR, SLR–AIR, and WDR–AIR indicated that the assays had less than chance agreement. The results demonstrate that current HI assays are not reliable as a sole diagnostic assay in the eastern massasauga. Furthermore, HI assays need to be evaluated by using other parameters to determine OPMV exposure in eastern massasaugas.

Male Movement and Body Size Affect Mate Acquisition in the Eastern Massasauga (Sistrurus Catenatus)

Abstract Knowledge of mating system characteristics can elucidate forces driving sexual selection. In male pitvipers, both male movement tactics and body size are predicted to be important determinants of reproductive success. We used radio telemetry to monitor free-ranging Sistrurus catenatus (Eastern Massasauga) from 2000 through 2002 to determine whether male movement tactics and body size affect mate acquisition. Reproductive behaviors peaked in late July to early August. Females were accompanied by multiple males per season (up to seven); however, male mate acquisition varied considerably with only three of 17 (18%) males located more than one female during a single mating season. During the mating season, male mean daily distance moved (21.8 m) and movement frequency (77%) were higher than during the nonmating season (13.3 m, 63%). Male movement rate and body mass were positively related to the number of females acquired, and heavier males were observed accompanying females as the mating season progressed. Our results indicate that both movement tactics and body size are important in the mating system of S. catenatus; however, direct measures of reproductive success will be necessary before assessing the intensity of sexual selection.

Development of Snake Fungal Disease after Experimental Challenge with Ophidiomyces ophiodiicola in Cottonmouths (Agkistrodon piscivorous)

Snake fungal disease (SFD) is a clinical syndrome associated with dermatitis, myositis, osteomyelitis, and pneumonia in several species of free-ranging snakes in the US. The causative agent has been suggested as Ophidiomyces ophiodiicola, but other agents may contribute to the syndrome and the pathogenesis is not understood. To understand the role of O. ophiodiicola in SFD, a cottonmouth snake model of SFD was designed. Five cottonmouths (Agkistrodon piscivorous) were experimentally challenged by nasolabial pit inoculation with a pure culture of O. ophiodiicola. Development of skin lesions or facial swelling at the site of inoculation was observed in all snakes. Twice weekly swabs of the inoculation site revealed variable presence of O. ophiodiicola DNA by qPCR in all five inoculated snakes for 3 to 58 days post-inoculation; nasolabial flushes were not a useful sampling method for detection. Inoculated snakes had a 40% mortality rate. All inoculated snakes had microscopic lesions unilaterally on the side of the swabbed nasolabial pit, including erosions to ulcerations and heterophilic dermatitis. All signs were consistent with SFD; however, the severity of lesions varied in individual snakes, and fungal hyphae were only observed in 3 of 5 inoculated snakes. These three snakes correlated with post-mortem tissue qPCR evidence of O. ophiodiicola. The findings of this study conclude that O. ophiodiicola inoculation in a cottonmouth snake model leads to disease similar to SFD, although lesion severity and the fungal load are quite variable within the model. Future studies may utilize this model to further understand the pathogenesis of this disease and develop management strategies that mitigate disease effects, but investigation of other models with less variability may be warranted.

Genetic analysis and captive breeding program design for the eastern massasauga Sistrurus catenatus catenatus

Abstract The eastern massasauga Sistrurus catenatus catenatus is a declining species for which a captive breeding program was established in 2006. To effectively manage wild and captive populations, an understanding of genetic diversity within the species is necessary. We analyzed mitochondrial DNA sequences of 186 individuals: 109 wild snakes from 34 U.S. and Canadian counties and districts, all 52 breeding program members (23 of known and 29 of unknown origin), 18 other captives of unknown origin, and 7 outgroup representatives of desert massasauga S. c. edwardsii, and western massasauga, S. c. tergeminus. Statistical parsimony, maximum likelihood, and maximum parsimony analyses all identified eastern massasaugas as divergent from western and desert massasaugas. We found 18 different haplotypes among eastern massasaugas, comprising three geographically and genetically differentiated NADH dehydrogenase II (ND2) subunits that potentially reflect post-Pleistocene range expansion from unglaciated into forme...

Disruptive Influences of Drought on the Activity of a Freshwater Turtle

Abstract Drought is an ecological challenge for turtle species worldwide and can be exacerbated by habitat fragmentation and loss, especially for small populations. We studied the activity of 16 Blandings turtles Emydoidea blandingii using radio-telemetry from 2005–2006 during consecutive drought and normal hydrological years at a fragmented preserve in northeastern Illinois, U.S.A. The preserve experienced drought conditions during 2005 with precipitation levels 20% below the 60 y average. Fine scale measures of activity (i.e., mean water depth at locations, proportion of unique locations, and proportion of locations in dry habitat) differed between years, whereas broad scale measures of activity (i.e., home range, movement distance) did not. On average only 41.3% of 2005 home ranges overlapped with 2006 home ranges suggesting space use shifted between years. Although most proportional habitat use remained unchanged between years, several individuals increased their use of riverine habitats when other wetland habitat dried. Our study underscores the need to examine the risks of severe environmental events on vulnerable populations.

Prey Preference and Diet of Neonate Eastern Massasaugas (Sistrurus c. catenatus)

Abstract Because prey acquisition in young organisms often has profound effects later in life, understanding the foraging ecology of early age classes is important. We examined diet and prey preference of neonate Eastern Massasaugas (Sistrurus c. catenatus) at Carlyle Lake, Clinton County, Illinois. Prey recovered from free-ranging neonates consisted primarily of southern short-tailed shrews (Blarina carolinensis). In feeding trials, neonates demonstrated a preference for snake prey, disinterest in anuran and insect prey and indifference toward mammal prey. Because of gape limitations, neonates may have difficulty ingesting small mammals, but snakes are comparably easier to ingest and are the most common prey item of young S. c. catenatus in other parts of their range. Blarina carolinensis has not been reported previously from the diet of S. c. catenatus as their ranges overlap only in southwestern Illinois. Blarina carolinensis is considerably smaller than most mammals preyed upon by older age classes and would be easier for neonates to ingest. Thus, at Carlyle Lake, snakes may not be as important a prey resource for neonate massasaugas as in other parts of their range due to the availability of B. carolinensis.