Pharmacokinetics of inhaled anesthetics in green iguanas (Iguana iguana)

OBJECTIVE: To test the hypothesis that differences in anesthetic uptake and elimination in iguanas would counter the pharmacokinetic effects of blood:gas solubility and thus serve to minimize kinetic differences among inhaled agents. ANIMALS: 6 green iguanas (Iguana iguana). PROCEDURES: Iguanas were anesthetized with isoflurane, sevoflurane, or desflurane in a Latin-square design. Intervals from initial administration of an anesthetic agent to specific induction events and from cessation of administration of an anesthetic agent to specific recovery events were recorded. End-expired gas concentrations were measured during anesthetic washout. RESULTS: Significant differences were not detected for any induction or recovery events for any inhalation agent in iguanas. Washout curves best fit a 2-compartment model, but slopes for both compartments did not differ significantly among the 3 anesthetics. CONCLUSIONS AND CLINICAL RELEVANCE: Differences in blood:gas solubility for isoflurane, sevoflurane, and desflurane did not significantly influence differences in pharmacokinetics for the inhalation agents in iguanas.     

Mycoplasmosis in green iguanas (Iguana iguana).

Mycoplasma iguanae was the suspected etiology of spinal disease in feral iguanas (Iguana iguana) from Florida. In an experimental infection study, juvenile iguanas were inoculated with M. iguanae intravenously or by instillation into the nares. Blood samples obtained at intervals postinoculation were all culture negative for mycoplasma. Gross anatomic and histologic findings at necropsy 12 wk postinoculation were unremarkable. Mycoplasmas were cultured in high numbers from the posterior choanae and upper trachea of some inoculated and control iguanas at necropsy. The 16S rDNA gene sequence of these isolates revealed they were all a previously undescribed strain, Mycoplasma insons proposed species nova. M. iguanae. Mycoplasma iguanae was not recovered from the conjunctivae, choanae, trachea, lung, coelomic cavity, blood, heart, liver, spleen, limb joints, brain, or spinal cord of inoculated iguanas, and the iguanas did not seroconvert. We conclude that M. iguanae is unlikely to be an agent of acute disease in iguanas and that M. insons can be considered as normal flora in the respiratory tract of iguanas.     

Pharmacokinetics of ketoprofen in the green iguana (Iguana iguana) following single intravenous and intramuscular injections.

The nonsteroidal antiinflammatory drug ketoprofen (KTP) is a commonly used antiinflammatory and analgesic agent in reptile medicine, but no studies documenting its pharmacokinetics in this species have been published. Ketoprofen was administered as a racemic mixture to green iguanas (Iguana iguana) intravenously (i.v.) and intramuscularly (i.m.) at 2 mg/kg. Pharmacokinetic analyses were performed and indicated that ketoprofen in iguanas administered by the intravenous route has a classical two-compartmental distribution pattern, a slow clearance (67 ml/ kg/hr) and a long terminal half-life (31 hr) compared to ketoprofen studies reported in mammals. When delivered by the intramuscular route, bioavailability was 78%. These data indicate the daily dosing that is generally recommended for reptile patients, as an extrapolation from mammalian data, may be more frequent than necessary.     

Cannabis intoxication in three Green iguanas (Iguana iguana)

This report describes clinical signs and plasma biochemical changes associated with significant cannabis consumption in three Green iguanas (Iguana iguana) which resulted in seizures, cardiovascular and digestive tract aberrations, elevated hepatic enzymes and bile acid concentrations for a number of weeks post recovery. One case required extensive antiseizuring therapy to recover. All Green iguanas eventually made a full recovery.     

Echocardiographic and radiographic findings in a cohort of healthy adult green iguanas (Iguana iguana)

ObjectivesTo describe characteristics of echocardiography and cranial coelomic radiography in a cohort of iguanas.AnimalsTwenty apparently healthy adult green iguanas (Iguana iguana) from a reptile sanctuary.MethodsPhysical examination, radiography, two-dimensional and color Doppler echocardiography were performed to assess cardiac structures and function, and any related normal or abnormal findings were recorded.ResultsEchocardiographic examination was possible without sedation and allowed visualization of the great vessels, atria, and ventricle. Some structures could not be evaluated in a minority of the iguanas due to individual differences in bony conformation and imaging quality. Suspected abnormal echocardiographic findings in 3 iguanas included pericardial effusion (n = 1) and enlarged caudal vena cava and/or sinus venosus (n = 2). Objective measurements were repeatable as assessed by within-subject coefficient of variation, and reliable as assessed by intra-observer intraclass correlation coefficient. Left atrial and ventricular measurements were significantly correlated with body weight. Valve regurgitation was common, with atrioventricular valve regurgitation present in 53% (9/17) and aortic or pulmonic valve regurgitation in 71% (12/17) of otherwise normal iguanas. A heart murmur was not appreciated during examination of any of the iguanas. Heart size cannot be measured radiographically due to superimposition and silhouetting of other coelomic structures. Echocardiographic or radiographic findings consistent with mineralization of the great vessels were present in 76% of iguanas (13/17).ConclusionsEchocardiography in iguanas is well tolerated without sedation and allowed both subjective evaluation and structural measurements. Valve regurgitation and great vessel mineralization were commonly observed in this cohort of apparently healthy adult iguanas.     

Cutaneous melanophoroma in a green iguana (Iguana iguana)

An adult, male, green iguana (Iguana iguana) of unknown age was presented with a history of an enlarging, dark, skin mass in the right axillary region. The mass was excised because neoplasia was suspected. Impression smears of the cut surface of the mass were prepared for cytologic examination, and the mass was fixed for histologic examination. The impression smears contained numerous, discrete, pigmented, neoplastic cells consistent with melanin-producing neoplastic chromatophores. Histologic findings were consistent with a cutaneous melanophoroma. By transmission electron microscopy, the intracytoplasmic pigment granules corresponded to numerous melanosomes and lower numbers of premelanosomes. Tissue sections of the tumor were immunoreactive for Melan A antigen and were negative for S-100 antigen. The cytologic, histologic, electron microscopic, and immunohistochemical findings of the neoplasm were consistent with those of melanophoroma, an uncommon neoplasm of reptiles. The present report augments the limited body of knowledge on cytomorphologic and immunohistochemical characteristics of pigmented neoplasms in reptiles.     

Alfaxalone anaesthesia in the green iguana (Iguana iguana)

ObjectiveTo characterise the anaesthetic effects of alfaxalone administered intramuscularly (IM) at 10, 20, and 30 mg kg^?1.Study designProspective, randomized cross-over study.AnimalsTen juvenile green iguanas (Iguana iguana) of mean body weight (±SD) 480 ± 134 g.MethodsAlfaxalone was administered IM in the triceps of both thoracic limbs. Times for anaesthetic induction, plateau and recovery periods were recorded. Skeletal muscle tone of the jaw, neck, thoracic limbs, pelvic limbs, and tail was scored. The palpebral, corneal and righting reflexes, and the response to painful stimuli were also assessed. Pulse rate and respiratory rate were recorded. Comparisons between different dosages and over time were made using anova.ResultsTimes are given for 10, 20 and 30 mg kg^?1 dosages respectively: mean time to maximal effect was 7.7 ± 2.2, 5.4 ± 1.7 and 3.9 ± 1.2 minutes; duration of the plateau phase was 11.3 ± 3.8, 22.1 ± 6.5 and 39.1 ± 11.5 minutes; recovery time was 10 ± 2.4, 17.5 ± 8.6 and 25 ± 7.1 minutes; and total anaesthetic duration was 29 ± 35.7, 45 ± 8.2 and 68 ± 9.8 minutes. Endotracheal intubation was possible in 40% of the subjects given 10 mg kg^?1 and in 100% subjects given both 20 and 30 mg kg^?1. Loss of response to a painful stimulus was seen in 0/10, 8/10 and 9/10 animals at 10, 20, and 30 mg kg^?1 respectively. There was an initial dose-dependent depression of respiration followed by a significant increase in frequency over time. In contrast, pulse rates decreased by 20% over the duration of the anaesthetic events.Conclusions and clinical relevanceIntramuscular administration of alfaxalone is a simple, rapid and reliable means of achieving relatively brief sedation or anaesthesia in healthy green iguanas. A dosage of 10 mg kg^?1 provides light sedation, appropriate for examination and venipuncture; 20 mg kg^?1 provides a level suitable for minor procedures or for endotracheal intubation and supplementation with inhalational anaesthesia; 30 mg kg^?1 produces an anaesthetic plane suitable for surgical procedures of limited duration (up to 40 minutes).     

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.     

Pharmacokinetics of ceftiofur and metabolites after single intravenous and intramuscular administration and multiple intramuscular administrations of ceftiofur sodium to sheep

Twenty-four sheep (38.0–54.1 kg body wt) were allocated into four treatment groups and dosed with ceftiofur sodium at 1.1 mg ceftiofur free acid equivalents (CFAE)/kg or 2.2 CFAE/kg using a complete two-route (intravenous, i.v.; intramuscular, i.m.), two-period crossover design, with a two-week washout between injections. After another two-week washout period, 12 sheep were selected and dosed with ceftiofur sodium i.m. for five consecutive days at either 1.1 or 2.2 mg CFAE/kg. After all injections, blood samples were obtained serially for determination of serum concentrations of ceftiofur and metabolites. The terminal phase half-lives derived from the last 3–5 concentration-time points were 350 and 292 min (harmonic means) after i.v. doses of 1.1 and 2.2 mg/kg, respectively, and 389 and 459 min after i.m. doses of 1.1 and 2.2 mg/kg, respectively. The i.m. bioavailability of ceftiofur sodium in sheep was 100%, and the area under the curve from time 0 to the limit of quantitation ( AUC _0–LOQ) was dose-proportional from 1.1–2.2 mg CFAE/kg body wt in sheep. After 5 daily i.m. doses of ceftiofur sodium at either 1.1 or 2.2 mg CFAE/kg there was minimal accumulation of drug in serum as assessed by the observed maximum serum concentration ( C _max), and serum concentrations were dose-proportional after the multiple dosing regimen.     

Pharmacokinetics of ceftiofur and metabolites after single intravenous and intramuscular administration and multiple intramuscular administrations of ceftiofur sodium to dairy goats

Twelve (12) lactating dairy goats (46–71 kg body wt at study initiation) were divided into four treatment groups and dosed with ceftiofur sodium at 1.1 mg ceftiofur free acid equivalents (CFAE)/kg or 2.2 CFAE/kg using a complete two route (intravenous, i.v.; intramuscular, i.m.), two-period crossover design, with a 2-week washout between injections. After another 2-week washout period, the goats were dosed with ceftiofur sodium i.m. for 5 consecutive days at either 1.1 or 2.2 mg CFAE/kg. The goats from the 2.2 mg/kg multiple dose group were dried off and the i.v. kinetic study repeated. After all injections, blood samples were obtained serially for determination of combined serum concentrations of ceftiofur and metabolites. After intravenous doses of 1.1 and 2.2 mg/kg, the harmonic means of the terminal phase half-lives were 171.8 and 233 min, respectively, for lactating does. The harmonic mean of the terminal phase half-life after an i.v. dose of 2.2 mg/kg in non-lactating does was 254 min. The AUC _0–∞ was significantly less and the clearance significantly greater during lactation. After i.m. doses of 1.1 and 2.2 mg/kg, the harmonic mean terminal phase half-lives were 163 and 156 min, respectively. The i.m. bioavailability of ceftiofur sodium in goats was 100%, and the AUC _0–∞ was dose-proportional from 1.1–2.2 mg CFAE/kg body weight. After five daily i.m. doses of ceftiofur sodium at either 1.1 or 2.2 mg CFAE, there was minimal accumulation of drug in serum as assessed by C _max, and serum concentrations were dose-proportional after the multiple dosing regimen.     

Effects of allopurinol on plasma uric acid levels in normouricaemic and hyperuricaemic green iguanas (Iguana iguana)

A two-phase cross-over therapeutic study was performed with 19 green iguanas (Iguana iguana) maintained within a preferred optimum temperature range of 26 to 37 degrees C. During phase 1, they were fed a normal vegetarian diet and medicated orally with either allopurinol or a placebo control once a day for seven days. Uric acid concentrations, total protein, packed-cell volumes (pcv) and bodyweights were recorded from each lizard before and after treatment to determine the effects of allopurinol. In phase 2, after a 10-day washout period, the iguanas were fed a high protein diet to induce hyperuricaemia. Normo- and hyperuricaemic iguanas that received 24.2 (3.2) mg/kg allopurinol had significantly lower mean (sd) uric acid concentrations (100.3 [53.1] micromol/l) than the controls (159.3 [100.3] micromol/l). There were no detectable interactions between the doses of allopurinol or placebo, and the iguanas' diet, weight, pcv or total protein. The allopurinol was well tolerated, and there was no significant clinical, gross or histological evidence of hepatic or renal toxicity in the iguanas that received the drug. However, in the kidneys of the hyperuricaemic iguanas that did not receive allopurinol there were proliferative changes in the glomeruli and degeneration of tubular epithelia. Allopurinol given orally at 25 mg/kg daily is able to reduce plasma uric acid levels by 41 to 45 per cent, and is therefore recommended for the treatment of hyperuricaemia in the green iguana.     

Severe dermatophytosis due to Trichophyton mentagrophytes var. interdigitale in flocks of green iguanas (Iguana iguana)

Objective : To describe the clinical, mycological, histopathological and molecular findings in green iguanas (Iguana iguana) affected with severe dermatophytosis in selected flocks near Tehran, Iran. Materials and Methods : Samples were collected from the scales of skin lesions and tested with standard mycological methods and dermatophyte‐specific PCR amplification analysis using the primer pair for the chitin synthase 1(CHS1) gene. Results : All iguanas were definitively diagnosed with dermatophytosis using both traditional and molecular diagnostic methods. PCR fingerprinting profiles using simple repetitive (GACA)4 primers showed that all diagnosed iguanas had the same pattern profile. Intraspecific variability was not observed for these isolates. Oligonucleotide sequencing of CHS1 gene PCR products confirmed Trichophyton mentagrophytes var. interdigitale as the infectious agent. Clinical Significance : These results suggest that (GACA)4‐based PCR has utility both as a simple and rapid method for identification of dermatophyte species and for differentiation of T. mentagrophytes variants.     

Aural-pharyngeal polyps associated with Cryptosporidium infection in three iguanas (Iguana iguana)

Cryptosporidium spp. infection was associated with aural-pharyngeal polyps in three iguanas (Iguana iguana). All iguanas were presented for masses protruding from the ear canal, and the disease was characterized by a chronic clinical course. The masses consisted of nests of cystic glands surrounded by abundant fibrous connective tissue and lined by hyperplastic cuboidal to pseudostratified columnar epithelium that was moderately to heavily colonized by cryptosporidial organisms. Electron microscopy revealed that the majority of organisms were trophozoites.     

Investigations on blood coagulation in the green iguana (Iguana iguana)

The prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time, kaolin clotting time (KCT), dilute Russell's viper venom time (DRVVT) and reptilase time, as well as five different plasma fibrinogen assays [gravimetry, Jacobsson method (extinction at 280 nm), Millar method (heat precipitation), kinetic turbidometry, Clauss method] and resonance thrombography were performed in 26 clinically healthy green iguanas. All assays were carried out in comparison with pooled normal canine plasma. In iguana plasma, the PT [median (x0.50) = 453-831 s, dependent on the reagent], APTT (x0.50 = 170-242 s, dependent on the reagent), thrombin time (x0.50 = 118 - > 1000 s, dependent on thrombin activity), KCT (x0.50 = 274 s), DRVVT (x0.50 = 349 s) and reptilase time (all samples > 1000 s) were widely scattered at the limit of measurability. Only fibrinogen concentrations measured using the Jacobsson method (x0.50 = 4.40 g/l) correlated well (r = 0.91) with gravimetry (x0.50 = 4.22 g/l). The results of this study indicate a limited suitability and a confined diagnostic significance of the selected methods in the green iguana. This may be caused by the species specificity of certain components of the reagents used, as well as a less optimal test system, i.e. relationship of test reagent to clotting factor concentrations in iguana plasma.     

Diagnosis and management of lymphoma in a green iguana (Iguana iguana)

CASE DESCRIPTION-A 2-year-old female green iguana was examined for anorexia and swelling and pain on palpation in the cranial cervical area. CLINICAL FINDINGS-Marked soft tissue swelling in the cranial cervical area with corresponding cystic swellings in the pharynx were noted. The iguana was considered to be 50% under the expected body weight, given diet and husbandry conditions. The WBC count was markedly elevated, characterized by heterophilia and lymphocytosis. Surgical exploration of the cranial cervical area and histologic and microbial testing identified lymphoma with secondary infection as the cause of the swelling. TREATMENT AND OUTCOME-The tumor was initially treated with a single 10-Gy fraction of radiation directed at the masses in the neck. A vascular access port was placed in the ventral abdominal vein, and a canine chemotherapy protocol was modified for use in the iguana. During the course of treatment, the protocol was modified twice. At 1,008 days from the initiation of treatment, the iguana appeared to be in remission. CLINICAL RELEVANCE-To our knowledge, this is the first reported use of radiation with doxorubicin, vincristine, cyclophosphamide, and prednisone to successfully manage lymphoma in a reptile. A vascular access port was used effectively for drug administration for an extended period. The doxorubicin, vincristine, cyclophosphamide, and prednisone protocol appeared to be safe and effective in this iguana for the management of lymphoma.     

Cytopathic herpesvirus infection in a green iguana (Iguana iguana).

A juvenile male green iguana (Iguana iguana) died 5 days following movement to a room 3-5 degrees C cooler than its previous housing. Gross necropsy lesions were limited to thin body condition. Histologically the animal had multifocal, random, moderate to severe, acute hepatocellular necrosis with intranuclear inclusion bodies at the periphery of the necrotic areas. Electron microscopy of the liver revealed icosahedral viral particles approximately 110 nm in diameter, consistent with a herpesvirus infection. Characteristics of the herpesvirus are similar to those described for iguanid herpesvirus 1.