Captive Reptiles Research Articles

Genomic fingerprinting and serotyping of Salmonella from Galápagos iguanas demonstrates island differences in strain diversity

Salmonella carriage patterns in wild and captive reptiles suggest that both geographical proximity and host ecological differences may determine bacterial diversity among reptile populations. In this study, we explore the relative importance of these factors on Salmonella diversity in free-living Galápagos iguanas. We isolated Salmonella enterica from marine iguanas (Amblyrhynchus cristatus) and land iguanas (Conolophus subcristatus and C. pallidus) living on two islands (Plaza Sur and Santa Fe). We evaluated Salmonella population patterns using genomic fingerprints, sequence typing and serotyping. Rep-PCR fingerprinting revealed significant grouping of isolates by iguana population. Island residence had the strongest effect on isolate similarity, but a smaller divergence among Salmonella isolates from different iguana ecotypes (land versus marine) was detected within each island. In contrast, sequence typing detected a marginal difference in isolate genotypes between islands. Sequence types corresponded strongly to serotype identity, with both islands hosting a unique serovar pool. Our findings suggest that both geographical location and host ecotype differences (either from within host strain selection or from differences in habitat use) contribute to Salmonella population patterns in the Galápagos Islands.

Fecal hormone patterns during non-ovulatory reproductive cycles in female veiled chameleons ( Chamaeleo calyptratus)

Reproductive failure, in particular preovulatory stasis, is a common problem in captive female reptiles. For a better understanding of its pathogenesis, the patterns of fecal estradiol (E2), testosterone (T), progesterone (P) and their metabolites of 21 anovulatory female veiled chameleons, Chamaeleo calyptratus, were compared with those of 25 animals which ovulated during at least one cycle over the study period. Regular, cyclical hormone patterns, consisting of E2 peaks followed by simultaneous T and P peaks, were observed in all animals, regardless of whether oviposition occurred, indicating continuous ovarian activity. P concentrations were; however, significantly lower in animals undergoing anovulatory cycles. The average time period between the E2 and the T peak was 24.8 days, between the E2 and the P peak 26.5 days, and between the T and P peak 2.6 days. The mean length of reproductive cycles between two sequential ovulatory complexes (oviposition to oviposition) was 132.5 days (range 112–156 days). The results provide evidence that reproductive “failure” occurs more frequently than suspected with some females alternating between ovulatory and anovulatory cycles without any outward evidence of the variation in ovarian cycles. It is proposed that this may be related to physiological adaptation to adverse environmental conditions for breeding and that husbandry factors in captivity are primarily responsible for the progression from a physiological to pathological process.

Yolk coelomitis in a white-throated monitor lizard (Varanus albigularis) : short communication

Yolk coelomitis as a result of pre-ovulatory follicular stasis is a common disorder in captive reptiles, especially in captive lizards of various genera. The clinical signs are generally fairly non-specific and diagnosis is based on clinical signs together with most of the common diagnostic modalities. The condition is most likely a husbandry and environment-related reproductive disorder. It has not been reported in wild free-living specimens. This report describes the clinical presentation and post mortem lesions in a white-throated monitor lizard that died during treatment for non-specific clinical signs related to a severe yolk coelomitis.

Managing the Reptile Patient in the Veterinary Hospital: Establishing a Standards of Care Model for Nontraditional Species

Abstract Based on a recent 2009 to 2010 national pet survey, reptiles remain popular as pets. Although, compared with reptiles, there may be more than 5 times as many dogs and 6 times as many cats, there is only 1 species of each of these domestic pets and more than 7500 different species of reptiles. Veterinarians working with domestic species need to recognize the requirements for managing these animals, along with some of the unique nutritional (e.g., calorie and nutritional differences between small and large breed dogs) and medical health differences among breeds; however, these differences pale in comparison with the species requirements and differences noted among reptiles. For this reason, it is important that veterinarians working with reptiles adopt a standards of care model to ensure that they are providing the most complete and balanced veterinary care possible for their reptile patients. The purpose of this article is to provide a review of the methods used for collecting a history, performing a physical examination, collecting and interpreting diagnostic tests, and reviewing the management of common diseases in captive reptiles.

Parasites of Selected Reptiles of the National Zoological Garden, Sri Lanka

The National Zoological Garden plays a vital role in conservation of reptiles in Sri Lanka. Since parasitic infestations of captive reptiles can impact their health, a survey for intestinal parasites and ectoparasites was conducted on 19 selected reptilian species (14 snakes, four chelonians, and one crocodilian) housed at the National Zoological Garden, Sri Lanka. Of the reptiles screened, 62% (N = 139) were infected with parasites; 66% and 24% exclusively harbored intestinal and ecto parasites, respectively, while 10% carried both types of parasites. Three ticks (Ixodidae), two adult cestodes, plerocercoid larvae, and four nematode species were recovered during this survey. Three types of nematode ova and a single type of digenian ova, protozoan cysts, L3 nematode larvae, and a protozoan were detected in the feces. In this first systematic survey of reptilian parasites in Sri Lanka, four new host-parasite records are documented.

Voluntary exposure of some western‐hemisphere snake and lizard species to ultraviolet‐B radiation in the field: how much ultraviolet‐B should a lizard or snake receive in captivity?

Studies of voluntary exposure to ultraviolet-B (UVB) radiation from the sun in the field were conducted in the southern US and Jamaica for 15 species of lizards and snakes occupying various habitats. Species were sorted into four zones of UVB exposure ranging from a median UV index of 0.35 for zone 1 to 3.1 for zone 4. Guidelines for UVB exposure in captivity of these and species occupying similar light environments are presented. Data for most species were collected during mid-day during the spring breeding season, which appeared to be the time of maximum exposure. For two species of Sceloporus studied more intensively there was significant variation of exposure among times of the day and among seasons. So, all-day studies over the entire active season are necessary to fully understand the pattern of natural exposure for a particular diurnal species. Environmental and body temperature and thermoregulation as well as UVB/vitamin D photoregulation influences exposure to UVB. Regressions allowing the inter-conversion of readings among some meters with different detector sensitivities are presented. Readings of natural sunlight predict the same photobiosynthetic potential for vitamin D as the same reading from artificial sources whose wavelength distribution within the UVB band of the source is comparable to that of sunlight. Research approaches to further increase our understanding of vitamin D and UVB use and requirements for squamate reptiles in captivity are outlined.

Chronic Urolithiasis and Subsequent Cystectomy in a San Esteban Island Chuckwalla, Sauromalus varius

ABSTRACT Cystic calculi were detected during physical examination of an adult San Esteban Island chuckwalla, Sauromalus varius. This lizard had developed calculi on five previous occasions, requiring multiple surgical interventions. Cystectomy was elected to resolve the current episode and to prevent any additional calculi from forming. Plasma osmolarity and biochemistry analyses were evaluated at regular intervals before and after removing the bladder. No adverse clinical or biochemical effects were observed. Cystectomy is a viable option for managing chronic urolithiasis in captive reptiles, however, because the bladder can be a site of post-renal modification of urine, it may not be appropriate in certain species or situations.

Dermatology in Reptiles

Abstract One of the most common reasons captive reptiles are presented to a veterinarian is for dermatologic disease. The purpose of this article is to provide readers a review of the most current information related to dermatologic diseases commonly diagnosed in captive reptiles. The article is divided into 2 sections to cover the most common groups of reptiles encountered in practice: 1) chelonians and 2) squamates (snakes and lizards). This review offers concise and practical diagnostic and therapeutic medical approaches that can be used when reptiles present with dermatologic abnormalities. Drug contraindications are highlighted to provide a quick and easy reference as to which drugs should not be used in reptiles.

Bronchodilators

Vitamin D is an essential hormone that regulates many different functions in vertebrates and can have a protective effect against various disease conditions. Providing exotic pets appropriate access to vitamin D, through the diet, ultraviolet B (UVB) exposure, or a combination of both, is important for veterinarians and exotic pet owners to consider. Although it is commonly thought that most animals derive the vitamin D they need through their diet, there are a number of species that appear to benefit more from UVB exposure. In addition, there has been minimal study to investigate appropriate dietary levels of vitamin D for many of our exotic pets. Although the recommendation of providing UVB lighting has been primarily limited to captive reptiles, research with other species (e.g., birds and small mammals) suggests that these animals may also benefit from this type of lighting. However, the provision of UVB is not without its potential side effects. The purpose of this article is to review the important roles of vitamin D in animals, the different methods animals use to acquire this hormone, the potential clinical signs associated with hypovitaminosis or hypervitaminosis D, the role of artificial UVB lighting in the synthesis of vitamin D, and the potential side effects associated with UVB radiation.

Rapid solving of a problem apparatus by juvenile black-throated monitor lizards (Varanus albigularis albigularis)

It is widely accepted that providing stimulus enrichment is an important part of the development and maintenance of behavior and well-being in mammals. However, extending this idea to non-avian reptiles has barely been explored, certainly as an aid to cognitive development. Monitor lizards have a reputation for being highly curious and intelligent lizards, but quantitative experiments are necessary to evaluate such impressions as well as the value of providing enrichment to captive squamate reptiles. In this study eight juvenile black-throated monitors, Varanus albigularis, were tested in their home enclosures with three presentations, at weekly intervals, of a novel task apparatus: a transparent food tube containing several prey. The food tube allowed the monitors to obtain prey by using hinged doors at either end of the tube to access food. All eight lizards learned to open the tube, insert head, and capture the prey within 10 min in the first trial. By the second trial, both mean latencies to access the tube and capture the first prey item decreased significantly, as did the use of ineffective responses such as shaking the tube. A further slight decrease occurred in the third trial. Due to the results of this and similar studies, serious consideration should be given to further testing of cognitive abilities in squamate reptiles. Incorporating problem solving tasks may also be useful to increase the activity level and captive well-being of squamate reptiles, especially monitor lizards.

Frequency of rhabdiasid nematodes in wild Crotalus durissus terrificus (serpentes, viperidae) from Botucatu region, São Paulo state, Brazil

The aim of the present study was to evaluate the frequency of rhabdiasid nematodes in recently captured Crotalus durissus terrificus snakes from São Paulo State, Brazil. Fifty snakes (34 males and 16 females) were studied and each one was evaluated for the presence of that nematode at the moment of receipt at the Institution and after 90 days of quarantine inside individual cages. Tracheopulmonary washeswere examined. Snakes that died during quarantine underwent necropsy and lung examination. Analysis of the results obtained at the two evaluation times (0 and 90 days), in addition to the data obtained during necropsies, showed that 44% (18 males and 4 females) of the C. d. terrificus snakes were naturally infected by rhabdiasid nematodes. These data demonstrate the parasitism level in natural conditions and are important for the sanitary handling of these reptiles in captivity.

Reptile-associated Salmonellosis in Man, Italy

To the Editor: Reptiles are reservoirs of a wide variety of Salmonella serotypes, including all Salmonella enterica subspecies and S. bongori. In reptiles born in captivity or kept as pets, S. enterica subsp. enterica is frequently isolated (1). Salmonella strains are well adapted to reptiles, and they usually cause asymptomatic infections in such animals, while retaining pathogenicity for warm-blooded animals. For several years, reptiles have been recognized as a source of human salmonellosis. In North America, reptile-associated salmonellosis (RAS) has been reported, particularly in children, the elderly, or immunocompromised persons; severe and fatal infections are described occasionally (2). In contrast, only a limited amount of information on RAS is available in Europe. We report a case of RAS that occurred in an adult man in Italy. A 32-year-old man had symptoms of enteritis. For 2 weeks, he had experienced intermittent watery diarrhea, mild fever, and abdominal pain. He was then treated with ciprofloxacin, and after 15 days of treatment, he recovered from enteritis. A stool sample, collected before treatment, underwent bacteriologic analysis, and Salmonella spp. were identified biochemically (api 20E, bioMerieux, Marcy l'Etoile, France) and by a polymerase chain reaction assay specific for the invA gene of Salmonella spp (3). Since the man was a reptile owner, RAS, rather than a foodborne infection, was initially suspected. He owned several cold-blooded animals; all had been tested for Salmonella spp. (at least 3 times at 2- to 3-week intervals), and results were negative. Three weeks before the onset of enteric symptoms, he acquired a boa (Boa imperator) that was subjected to routine analysis for Salmonella spp. in our laboratories (1). Salmonella spp. were isolated from a cloacal swab of the snake. Subsequently, both the human and reptile Salmonella isolates were characterized as S. enterica serovar Paratyphi B. In addition, both strains were found to be d-tartrate–fermenting (dT+) biovars (4), susceptible to ampicillin, amoxicillin-clavulanic acid, cephalothin, ceftazidime, gentamicin, streptomycin, chloramphenicol, tetracycline, neomycin, nalidixic acid, norfloxacin, and ciprofloxacin and resistant to sulfamethoxazole and co-trimoxazole. By pulsed-field gel electrophoresis analysis of DNA, the strains displayed the same pattern, which suggests a clonal origin (4). The isolates were also assayed for virulence-associated genes. The SopE1 gene was detected in both isolates, and the avrA gene was not detected, which is consistent with an invasive pathovar of S. Paratyphi B (4). Conversely, the spvC, pef, and sef genes were not detected (5). In recent years, a general increase in RAS detection has been observed, which may be the result of the increasing diffusion of reptiles as pets and a better awareness of RAS risk. In the United States, annual reports of RAS cases are published by the Centers for Diseases Control and Prevention (2). In Europe, studies on free-living and captive reptiles have shown a high prevalence of Salmonella spp (1). Nevertheless, national surveillance systems for RAS do not exist, and epidemiologic data are incomplete. Notably, since Sweden became a member of the European Union in 1995, and the import restriction rules for reptiles were removed, a marked increase in RAS was observed in that country (6). As the deregulation of the trade in reptiles is applied, in agreement with the European Union laws, a similar scenario may be projected in other European countries. As is the case for nontyphoid salmonellosis, RAS may be underestimated, especially if patients are not hospitalized. Although a few cases of RAS have been previously reported in children in Italy (7,8), this report provides the first description of RAS in adults. S. Paratyphi B dT+, also known as S. enterica serovar Java, has been isolated in reptiles and tropical fish and has been associated with epidemics of human salmonellosis acquired from food, such as goat milk or chicken (9). The evidence shows that salmonellosis by S. Paratyphi B dT+ apparently occurs more frequently in adults (10), while so-called exotic reptile strains seem to be more prone to causing salmonellosis in children (7,8), which has led to the proposition that S. Paratyphi B dT+ strains may be highly pathogenic. By screening virulence-associated genes, both our isolates were found to be SopE1+ and avrA–, a pattern usually observed in the systemic pathovars of S. Paratyphi B (4) and associated with invasiveness, which suggests a high pathogenic potential. Accordingly, strict preventive sanitation measures should be adopted when handling reptiles (2), and reptiles should be always regarded as a potential source of pathogenic Salmonella strains for humans.

An Evaluation of the Gray Cricket, Acheta domestica, as a Source of Oxyurids for Reptiles

ABSTRACT Lay publications and internet forums have anecdotally suggested that commercially-bred gray crickets, Acheta domestica, are a source of oxyurids for insectivorous reptiles. This study was designed to determine if commercially bred crickets harbor oxyurids. Two-thousand five hundred gray crickets purchased from five different commercial insect breeders were evaluated for the presence of oxyurids. Attempts to isolate oxyurid eggs from the crickets were achieved by passage of homogenized crickets through a series of sieves and interpretation by flotation in a sucrose solution. No pinworm eggs were identified. These findings suggest that commercially bred crickets do not serve as a source of oxyurids for captive reptiles.

ABSENCE OF DETECTABLE SALMONELLA CLOACAL SHEDDING IN FREE-LIVING REPTILES ON ADMISSION TO THE WILDLIFE CENTER OF VIRGINIA

Salmonellosis is an important reptile-associated zoonotic infection in the United States. Cloacal swabs were collected from reptiles admitted to the Wildlife Center of Virginia, Waynesboro, Virginia, cultured for Salmonella using Hektoen and xylose lysine deoxycholate agars, and inoculated in selenite broth. All three were incubated at 37 degrees C for 18-24 hr. Seventy-five animals were included in the study, representing eight species, 34 eastern box turtles (Terrapene carolina carolina), 14 eastern painted turtles (Chrysemys picta picta), 14 snapping turtles (Chelydra serpentina), 6 black rat snakes (Elaphe obsoleta obsoleta), 2 redbelly turtles (Pseudemys rubriventris), 2 yellowbelly sliders (Trachemys scripta scripta), 2 eastern garter snakes (Thamnophis sirtalis sirtalis), and 1 eastern river cooter (Pseudemys concinna concinna). All cultures were negative for Salmonella spp., which is in contrast to the high prevalence of Salmonella cloacal shedding reported in captive reptiles but similar to previous reports in free-living North American reptiles. We recommend, nonetheless, practicing proper hygiene methods when handling and housing all reptiles.

Ecology of Lutzomyia (Nyssomyia) whitmani in an urban area in Maringá, Paraná, Brazil

To study the fauna, hours of activity and seasonality of phlebotomines in forest animal habitats in the Ingá Park, on the urban perimeter of the municipality of Maringá, Paraná State, Brazil. Phlebotomines were collected on the urban perimeter using Shannon traps from 6:00 p.m. to 6:00 a.m. and Falcão traps from 8:00 p.m. to 12:00 midnight, on two nights per month from October 1998 to September 2000. The Shannon traps were installed close to forest animal habitats and on the banks of the Moscados stream; the Falcão traps were placed in shelters for captive birds, forest mammals and reptiles. The Shannon traps yielded 13,656 phlebotomines, with predominance of Lutzomyia whitmani (98.7%). The Falcão traps yielded 4,040 phlebotomines, with L. whitmani again predominating (96.3%). L. whitmani was most frequently found between 12:00 midnight and 2:00 a.m. in the Shannon traps. This species was most frequently collected in the months of August (55.1%) in the Shannon traps, and in March 1999 (19.2%), November 1999 (15.9%) and August 2000 (20.6%) in the Falcão traps. More phlebotomines were collected in Falcão traps installed in shelters for captive mammals (84.0%). There was a clear predominance of L. whitmani in the Ing Park. The greatest frequency of L. whitmani was in August from Shannon traps, and in March and November from Falcão traps. The peak activity of L. whitmani took place between 12:00 midnight and 2:00 a.m.

Outbreak of salmonellosis in a zoologic collection of lorikeets and lories (Trichoglossus, Lorius, and Eos spp.).

During August 2001, a syndrome characterized by acute lethargy and dyspnea was observed in a population of 45 lorikeets and lories in an open-air zoologic exhibit. The first death occurred on August 10, and within the next 12 days, nine more birds died (22% mortality rate). Hepatomegaly, reddening and congestion of the lungs, and injection of the serosal surface of the intestines were the common gross findings. Histologic changes, including fibrinonecrotic hepatitis and splenitis, bacterial emboli (liver, spleen, lung, kidney, proventriculus), pulmonary congestion and hemorrhage, and enteritis, were indicative of an acute, overwhelming bacterial septicemia. Salmonella typhimurium, with the same antibiogram, was isolated from four birds. Several birds had attacked and killed a snake on July 24, and Salmonella serogroup B (untypeable) was isolated from intestine and kidney samples of a garter snake caught in the open-air exhibit on August 28. Salmonella was also isolated from environmental samples of the exhibit but not from food preparation areas. After antimicrobial therapy, Salmonella spp. was not isolated from the surviving birds. The source of Salmonella in this outbreak remains unknown, but infection either directly or indirectly from snakes in the exhibit is possible. Contact between captive psittacine populations and reptiles should be avoided to prevent the risk of salmonellosis.

Use of serology in reptile medicine

Serologic assays are emerging as powerful tools for both diagnosing and screening collections of reptiles for exposure to and infection with certain pathogens. For the most part, these tests were developed in research laboratories with a specific interest in diseases of captive and free-ranging reptiles. Relatively few are commercially available, with most offered through individual research laboratories or universities. Tests have been developed for exposure to paramyxovirus of snakes, mycoplasma of tortoises and crocodilians, her-pesvirus infection of marine turtles and tortoises, cryptosporidium of snakes, and spirorchid trematodes of sea turtles. Of the various serologic tests, enzyme-linked immunosorbent assay (ELISA) is becoming the test with the most application. Although ELISA is relatively simple and has certain positive attributes such as high sensitivity and specificity, in the indirect format it does require specific anti-reptile immunoglobulins that recognize and bind to the antibody being assayed. In this report, we review reptile humoral immunity for the major orders of reptiles, assays available for determining exposure of reptiles to specific pathogens, and factors affecting the immune response of reptiles.

Salmonella enterica in reptiles of German and Austrian origin

Captive reptiles are routinely identified as reservoirs of Salmonella spp. and the number of reports about reptile-associated salmonellosis is increasing. In the present study, Salmonella were detected in 86 of 159 (54.1%) faecal reptile samples cultured. The percentage of Salmonella positive samples was significantly lower in turtles as compared with lizards and snakes, as Salmonella were only detected in one sample from a single turtle out of 38 turtles investigated. In all, 42 different Salmonella serovars were found. All isolated Salmonella belonged to the species enterica, predominantly to the subspecies I ( n=46) and IIIb ( n=30), but also to subspecies II ( n=3), IIIa ( n=6) and IV ( n=2). All isolates were sensitive to the antimicrobials examined. A comparison between the reptile owners indicated that either no Salmonella were found, or that Salmonella could be isolated from all or nearly all animals of the respective owners. A significantly higher percentage of Salmonella positive reptiles was detected in the group of owners who purchase reptiles in comparison with pure breeders. A total of 88.9% of Salmonella isolates were found in samples of reptiles bought in pet shops and 58.8% in samples from wild-caught animals. The high percentage of Salmonella in reptiles in our study confirms the risk for the transmission of the infection to humans.

A longitudinal study of Escherichia coli strains isolated from captive mammals, birds, and reptiles in Trinidad.

A longitudinal study was conducted of the prevalence and characteristics of Escherichia coli in mammals, birds, and reptiles housed at the Emperor Valley Zoo, Trinidad. During a 6-mo study period, swabs were obtained from fecal samples that were randomly collected from the enclosures of animals from these three taxonomic groups every 3 wk. With snakes, both cloacal and fecal swabs were obtained. Fecal and cloacal swabs were cultured for E. coli on eosin methylene blue agar. The production of mucoid colonies and hemolytic colonies and non-sorbitol fermenter status were identified. The occurrence of O157 strains was determined amongst E. coli isolates that were non-sorbitol fermenters, and the disc diffusion method was used to determine the antibiograms of isolates. The frequency of E. coli isolation was significantly higher in mammals compared with birds and reptiles. Overall, the frequencies of isolation of E. coli from omnivores. herbivores, and carnivores, 87.2%, 70.0%, and 57.3%, respectively, regardless of animal class, were significantly different. Most (99.6%) of the E. coli isolates tested for antibiotic sensitivity exhibited resistance to one or more of the eight antimicrobial agents used. The possession of phenotypic virulence markers by the E. coli isolates studied and the generally high resistance to antimicrobial agents may have health implications for the zoological collection.

Preliminary findings of Salmonella spp. in captive green iguanas ( Iguana iguana) and their environment

Captive reptiles are routinely identified as reservoirs of Salmonella spp. and reports of reptile-associated salmonellosis are increasing. Unfortunately, little is known about the epidemiology of Salmonella spp. and green iguanas. We did a limited survey of a green-iguana farm in El Salvador to identify sources of Salmonella spp. in green iguanas and their environment. A limited number of samples for microbiological culture were collected from iguanas (adult, hatchling, and embryos) and their environment (food, water, soil, shelter, insects, and wild-caught lizards). Salmonella spp. was isolated from the intestine of both adult (3/20) and hatchling iguanas (8/20). There was no evidence of Salmonella spp. in the reproductive tracts of female iguanas (0/10). Salmonella spp. was isolated from the surface of 40% (7/16) of the egg surfaces tested. Salmonella spp. was not identified from the externalized yolk-sac of the iguana embryos tested. Soil samples from a breeding pen and a nest were both positive for Salmonella spp. Eight different Salmonella spp. serotypes were identified in this survey. These results suggest that horizontal transmission of Salmonella spp. is a potential source of exposure to hatchling iguanas at this facility.