Diseases and causes of mortality among sea turtles stranded in the Canary Islands, Spain (1998-2001)

Citrobacter freundii-associated lesions in stranded loggerhead sea turtles (Caretta caretta)

Citrobacter freundii, an opportunistic bacterial pathogen belonging to the family Enterobacteriaceae, has been sporadically reported in sea turtles. Here, the authors describe 3 unusual lesions associated with C. freundii infection in 3 loggerhead sea turtles stranded on the coast of Gran Canaria Island, Spain. It is possible that these 3 distinct lesions played a major role in the death of these turtles. The first turtle had caseous cholecystitis, a lesion not previously described in sea turtles. The second turtle had large intestinal diverticulitis, a rare condition in loggerheads. The third turtle had bilateral caseous salt gland adenitis. Histologically, numerous gram-negative bacilli were observed at the deepest edge of inflammation in all cases. Pure cultures of C. freundii were obtained from these 3 lesions. Molecular detection of C. freundii DNA in formalin-fixed paraffin-embedded samples from the lesions of the 3 turtles confirmed the microbiological isolation. These cases, in addition to expanding the limited body of knowledge on bacterial infections in sea turtles, highlight the potential pathogenic role of C. freundii in loggerhead turtles.

RETROSPECTIVE ANALYSIS OF BLOOD CULTURES AND THEIR ASSOCIATION WITH CLINICAL FINDINGS AND OUTCOME IN GREEN SEA TURTLES (CHELONIA MYDAS) AT A FLORIDA SEA TURTLE REHABILITATION FACILITY, 2017-2020

Septicemia is commonly suspected of sea turtles entering rehabilitation. However, blood culture results of green sea turtles (Chelonia mydas) are infrequently reported in the literature. Aerobic blood cultures were performed for intake examinations of 167 green sea turtles undergoing rehabilitation at Brevard Zoo's Sea Turtle Healing Center, Melbourne, Florida, USA from 2017 to 2020. The incidence of positive cultures during intake examinations was 24% (40/167). The most common bacterial isolates identified were Vibrio alginolyticus, Shewanella algae, Achromobacter xylosoxidans, Photobacterium damselae, Sphingomonas paucimobilis, and Vibrio parahaemolyticus. There was a statistically significant association (P < 0.05) between culture status and evidence of external injury. There was no significant association between culture status and Caryospora-like coccidia infection, or fibropapillomatosis. Culture-positive turtles had significantly lower (P < 0.05) total white blood cell, lymphocyte, monocyte, total protein, albumin, and calculated globulin values compared to turtles with negative blood cultures. Significantly more culture-positive turtles died in rehabilitation compared to culture-negative (P = 0.042). Positive blood cultures suggestive of septicemia are commonly found during intake examinations at a Florida sea turtle rehabilitation facility.

Evaluation of sea turtle morbidity and mortality within the Indian Ocean from 12 years of data shows high prevalence of ghost net entanglement

Anthropogenic activities can negatively affect sea turtle populations. Quantifying the effect of human actions on these threatened species can help guide management strategies to reduce adverse impacts. However, such assessments require extensive effort and resources and as such have not been carried out in many areas of important sea turtle habitat, including the Republic of the Maldives (Maldives). Here, we utilise 12 years of data (2010-2022) collected from marine turtle stranding and rehabilitation cases from across the Maldives to identify the key threats in this region. Olive ridley turtles were found stranded or injured most frequently (74.7% of total cases), along with hawksbill (15.2%), and green (10.1%) turtles. Anthropogenic factors were the primary cause of injury or stranding in 75.2% of cases with entanglement in ghost fishing gear being the most common (66.2% of all cases). Other causes of morbidity, such as from turtles being kept as pets (5.6%), boat strikes (<1%), bycatch (<1%), and poaching (<1%) were recorded less frequently. Olive ridley turtles were more likely to have injuries associated with entanglement than other species and showed a peak in admissions during the northeast monsoon, in the period following the known arribada nesting season in nearby India. Turtles admitted to rehabilitation following entanglement were released a mean of 70 days sooner and had 27.5% lower mortality rates than for other causes of admission. This study highlights the high prevalence of ghost net entanglement of sea turtles within the Maldives. The topic of ghost fishing is of global importance and international cooperation is critical in tackling this growing issue.

DETERMINATION OF ECHOCARDIOGRAPHIC TECHNIQUES FOR CLINICAL ASSESSMENT OF GALAPAGOS (CHELONOIDIS NIGRA COMPLEX) AND ALDABRA (ALDABRACHELYS GIGANTEA) TORTOISES

The first objective of this study was to establish clinically relevant techniques for cardiac echocardiography in nonanesthetized Galapagos (Chelonoidis nigra complex) and Aldabra (Aldabrachelys gigantea) tortoises. A second objective was to establish guidelines for determining normal echocardiographic anatomy and function in both species. Select echocardiographic reference values were defined for 17 healthy Galapagos tortoises and 27 healthy Aldabra tortoises. Tortoises were either placed in ventral recumbency on an elevated surface or allowed to stand in a natural position by using food distraction. An ultrasound probe was applied in the left or right cervicobrachial window and was positioned in two long axis views to evaluate the three chambers of the heart and the associated great vessels, the presence of pericardial effusion, the atrioventricular inflow velocities, and pulmonic and aortic outflow velocities. The heart rate was 28 ± 12 (median ± SD) bpm, and the ejection fraction was 60.5 ± 10%. Thirty-four of 44 tortoises had identifiable physiologic pericardial effusion. All tortoises were successfully imaged using the techniques described, with consistent identification of cardiac structure and assessment of function. This study provides echocardiographic reference intervals for the clinical evaluation of suspected cardiac disease in captive-managed Galapagos and Aldabra tortoises.

Loggerhead Sea Turtle as Possible Source of Transmission for Zoonotic Listeriosis in the Marine Environment

Listeria monocytogenes is an ubiquitous pathogen isolated from different host species including fish, crustaceans, and molluscs, but it is rarely a pathogenic microorganism to marine reptiles. In particular, only two cases of fatal disseminated listeriosis have been described in the loggerhead sea turtle (Caretta caretta). In this study, we describe a lethal case of L. monocytogenes infection in a loggerhead sea turtle. The turtle was found alive, stranded on a beach in North-eastern Italy, but perished soon after being rescued. The autoptic examination revealed that heart, lung, liver, spleen, and urinary bladder were disseminated with multiple, firm, 0.1-0.5 mm sized, nodular, white-green lesions. Microscopically, these lesions corresponded with heterophilic granulomas with Gram+ bacteria within the necrotic center. Furthermore, the Ziehl-Neelsen stain was negative for acid-fast organisms. Colonies isolated from heart and liver were tested through MALDI-TOF for species identification, revealing the presence of L. monocytogenes. Whole Genome Sequencing on L. monocytogenes isolates was performed and the subsequent in silico genotyping revealed the belonging to Sequence Type 6 (ST 6); the virulence profile was evaluated, showing the presence of pathogenicity islands commonly observed in ST 6. Our results further confirm that L. monocytogenes should be posed in differential diagnosis in case of nodular lesions of loggerhead sea turtles; thus, given the zoonotic potential of the microorganism, animals should be treated with particular caution. In addition, wildlife animals can play an active role as carriers of possibly pathogenetic and virulent strains and contribute to the distribution of L. monocytogenes in the environment.

Bacterial Infections in Sea Turtles

Sea turtles are important for the maintenance of marine and beach ecosystems, but they are seriously endangered due to factors mainly related to human activities and climate change such as pollution, temperature increase, and predation. Infectious and parasitic diseases may contribute to reducing the number of sea turtles. Bacteria are widespread in marine environments and, depending on the species, may act as primary or opportunistic pathogens. Most of them are able to infect other animal species, including humans, in which they can cause mild or severe diseases. Therefore, direct or indirect contact of humans with sea turtles, their products, and environment where they live represent a One Health threat. Chlamydiae, Mycobacteria, and Salmonellae are known zoonotic agents able to cause mild or severe diseases in sea turtles, other animals, and humans. However, other bacteria that are potentially zoonotic, including those that are antimicrobially resistant, are involved in different pathologies of marine turtles.

Marina Observation of Sea Turtles: Establishing a Database of Intracoastal Waterway Green Sea Turtles in Northeast Florida

As conservation efforts regarding green sea turtles, Chelonia mydas, continue, it is imperative to document behaviors and foraging habits/habitats of understudied populations. We have conducted an 18-month study dedicated to photographing the local population feeding alongside floating docks within the Guana Tolomato Matanzas estuary to determine the capability of matching head scale patterns efficiently through a pattern matching program: HotSpotter. To date, 195 unique sea turtles have been identified between two different marinas located in St. Augustine, FL. Of these, 98 were spotted more than once, with 39 of them being "tracked" for longer than a year. Temperature trends were also monitored in conjunction, showing that more individuals appeared during the warmer months of the year. The evidence, overall, indicates that these locations host a resident population of green sea turtles, leading to the need for a discussion on potential threats originating from the usage of these marinas by humans.

Clinical Findings, Management, Imaging, and Outcomes in Sea Turtles with Traumatic Head Injuries: A Retrospective Study of 29 Caretta caretta

Sea turtles are considered endangered species, largely due to anthropogenic activities. Much of the trauma in these species involves the carapace and skull, resulting in several degrees of damage to the pulmonary and nervous systems. Among traumatic injuries, those involving the skull can be complicated by brain exposure, and turtles with severe skull injuries that have nervous system impairment, emaciation, and dehydration can often die. Between July 2014 and February 2022, a total of 1877 loggerhead sea turtles (Caretta caretta) were referred for clinical evaluation at the Sea Turtle Clinic (STC) of the Department of Veterinary Medicine of the University of Bari. A retrospective study of 29 consecutive cases of loggerhead sea turtles (Caretta caretta) with skull lesions of different degrees of severity is reported. On admission, physical and neurological evaluations were performed to assess and grade the lesions and neurological deficits. In 20 of the 29 sea turtles with more serious head trauma, computed tomography (CT) findings in combination with physical and neurological assessment enabled the evaluation of the potential correlation between deficits and the extent of head injuries. All sea turtles underwent curettage of the skull wounds, and the treatment protocol included the use of the plant-derived dressing 1 Primary Wound Dressing^® (Phytoceutical AG, Endospin Italia) applied on the wound surface as a primary dressing. Out of 29 sea turtles, 21 were released after a time ranging from a few days to 8 months. To the best of our knowledge, the literature lacks specific data on the incidence, correlations with neurological deficits, complications, and survival rate of loggerhead sea turtles with traumatic head injuries.

Identification of a novel Neorickettsia species in a Kemp's ridley sea turtle with granulomatous nephritis and development of a quantitative PCR assay

An adult male Kemp's ridley turtle was found dead on the coast of Kenedy County, Texas, in August 2019 with bilateral severe, diffuse granulomatous nephritis. Pan-bacterial 16S rRNA gene polymerase chain reaction (PCR) and amplicon sequencing of affected tissue indicated the presence of a Neorickettsia. Neorickettsia is a genus of obligate intracellular Alphaproteobacteria that are transmitted by digenean trematodes. For further characterization, primers were designed to amplify and sequence the groEL gene. Phylogenetic analysis found that the organism was distinct from other known species to a degree consistent with a novel species. Immunohistochemistry using an antibody directed against a Neorickettsia surface protein showed bacterial clusters within the renal granulomas. A species-specific quantitative PCR was designed and detected the organism within the liver and colon of the index case. A quantitative PCR survey of grossly normal kidneys opportunistically collected from additional stranded sea turtle kidneys detected this organism in five of 15 Kemp's ridley turtles, two of nine green turtles, and neither of two loggerhead turtles. Recognition of this novel organism in an endangered species is concerning; additional work is underway to further characterize the potential of this organism as a pathogen of sea turtles.

Symblepharon, Ankyloblepharon, and Salt Gland Dysfunction in a Loggerhead Sea Turtle (Caretta caretta)

Adhesions involving the bulbar and the palpebral conjunctiva (Symblepharon) may interfere with tear drainage, cause chronic conjunctivitis, and reduce ocular motility. This condition may be associated with adhesion of the edges of the upper and lower eyelids (ankyloblepharon). The present case describes bilateral symblepharon, ankyloblepharon and salt gland dysfunction in a juvenile Caretta caretta. The loggerhead presented both eyelids swollen, ulcerated, and not separable when rescued. Eye examination was not possible, but ultrasonography showed right bulbar integrity, while the left eye was smaller, with a thicker cornea that had lost its normal doubled lined structure. Surgical dissection of the fibrous adhesions between the palpebral and bulbar conjunctiva, cornea, and third eyelid was performed, and large dacryoliths were removed. The microscopic findings were consistent with chronic keratoconjunctivitis. Ultrastructurally, no virus-like particles were observed. In addition, tissue samples were negative for herpesvirus by qualitative PCR. The eyelids of both eyes and the corneal epithelium of the right eye healed; moreover, the vision was restored in the right eye. There were no recurrences after 12 months of follow-up, and the turtle was released 16 months after the end of treatments on the southern Tyrrhenian coast in the western Mediterranean Sea. To the authors’ knowledge, this is the first report of symblepharon with ankyloblepharon and salt gland dysfunction in Caretta caretta turtle. Ocular ultrasonography was helpful in the preliminary diagnostic work-up.

Aggravation of hepatic lipidosis in red-footed tortoise Chelonoidis carbonaria with age is associated with alterations in liver mitochondria

The occurrence of hepatic lipidosis is commonly reported in different reptilian species, especially in animals under captivity. Liver accumulation of fat is associated with disorders, better described in mammals as non-alcoholic fatty liver diseases (NAFLD), ranging from simple steatosis, to non-alcoholic steatohepatitis (NASH), and to more severe lesions of cirrhosis and hepatocellular carcinoma. Mitochondria play a central role in NAFLD pathogenesis, therefore in this study we characterized livers of ad libitum fed captive red-footed tortoise Chelonoidis carbonaria through histological and mitochondrial function evaluations of juvenile and adult individuals. Livers from adult tortoises exhibited higher levels of lipids, melanomacrophages centers and melanin than juveniles. The observed high score levels of histopathological alterations in adult tortoises, such as microvesicular steatosis, inflammation and fibrosis, indicated the progression to a NASH condition. Mitochondrial oxygen consumption at different respiratory states and with different substrates was 30 to 58% lower in adult when compared to juvenile tortoises. Despite citrate synthase activity was also lower in adults, cardiolipin content was similar to juveniles, indicating that mitochondrial mass was unaffected by age. Mitochondrial Ca²⁺ retention capacity was reduced by 70% in adult tortoises. Overall, we found that aggravation of NAFLD in ad libitum fed captive tortoises is associated with compromised mitochondrial function, indicating a critical role of the organelle in liver disease progression in reptiles.

Comparison Between Effects of Four Crystalloid Solutions on Acid-Base and Electrolyte Abnormalities in Stranded Juvenile Loggerhead Sea Turtles (Caretta caretta)

Dehydration, electrolyte abnormalities, and acid-base alterations are common findings in stranded sea turtles. Fluid therapy is essential for reestablishment of homeostasis. The aim of this study was to compare the efficacy and effects on acid-base and electrolyte status of four different crystalloids (0.9% NaCl solution, 0.9% NaCl and lactated Ringer's solutions 1:1 ratio, Plasmalyte, and Jarchow's solution) in 63 stranded juvenile loggerhead turtles (Caretta caretta). Crystalloid fluids were administered intracoelomically on the day of admission for a duration of three consecutive days at a rate of 20 mL/kg/day through the inguinal fossa. Blood samples were collected at three timepoints: on admission, 24 h after discontinuing fluid therapy and prior to release. Samples were analyzed using a portable electronic blood analyzer for pH, pCO₂, pO₂, bicarbonate, lactate, sodium, potassium, chloride, glucose, and BUN concentration. Thirty-four loggerhead turtles (53.9%) had some type of acid-base alteration at the time of admission. The combination of 0.9% NaCl and lactated Ringer's solutions resulted in the highest percentage of improved/resolved acid-base and electrolyte abnormalities (33.4 % more animals with normal acid-base status compared to the admission time) compared to Jarchow's solution, which was the least effective (15.8% decrease in the number of animals with normal acid-base status compared to the admission time). This study constitutes the second controlled study of fluid therapy in sea turtles, and corroborates the recommendation made previously on the use of 0.9% NaCl + lactated Ringer solution to resolve mild to moderate acid-base alterations in juvenile loggerhead turtles. In addition, convalescent acid-base, electrolyte and plasma biochemical reference intervals are also provided as a standard profile for sea turtle rehabilitation centers.

Bacterial and fungal pathogens in granulomatous lesions of Chelonia mydas in a significant foraging ground off southern Brazil

The green sea turtle Chelonia mydas inhabit near-shore areas exposed to threatening anthropogenic activities. The granulomatous lesions in these animals may indicate infectious diseases that can be associated with environmental contamination and hazards to human health. This study aimed to characterize the granulomatous inflammation associated with bacterial and fungal infection in C. mydas off Paraná state. From September 2015 to February 2019, systematic monitoring was performed by the Santos Basin Beach Monitoring Project for sea turtles'carcasses recovery, necropsy, and cause of death diagnosis. The tissue samples were fixed in buffered formalin 10% for histochemical analysis and frozen for molecular analysis to fungi detection (Internal Transcribed Spacer region of the nuclear rDNA) and bacteria detection (16S ribosomal gene). From a total of 270 C. mydas, granulomatous lesions were observed in different organs of 63 (23.3%) individuals. The histological analysis indicated lesions in 94 organs, affecting most respiratory and digestive systems. Bacteria were identified in 25 animals, including an acid-fast bacteria detected in one animal, and fungi in 24 C. mydas. The fungi species included the genus Candida (Candida zeylanoides, n = 3), Yarrowia (Yarrowia lipolytica, n = 9; Yarrowia deformans, n = 5; and Yarrowia divulgata, n = 1), and Cladosporium anthropophilum (n = 1). No species of bacteria was identified by molecular testing. All fungi species identified are saprobic, some are important to food and medical industries, but are also pathogens of humans and other animals. Therefore, long-term monitoring of these pathogens and the C. mydas health may indicate changes in environmental quality, possible zoonotic diseases, and their effects.

Pharmacokinetic characteristics of danofloxacin in green sea (Chelonia mydas) and hawksbill sea (Eretmochelys imbricata) turtles

To date, the number of green sea and hawksbill sea turtles is in decline due to environmental, anthropogenic, and pathological factors. The present study described the pharmacokinetic characteristics of danofloxacin (DNX) in green sea and hawksbill sea turtles, following single intravenous (i.v.) and intramuscular (i.m.) administrations at single dosages of 6 mg/kg body weight (b.w.). Blood samples were collected at assigned times up to 168 h. DNX in the harvested plasma was cleaned up using liquid-liquid extraction and analyzed using a validated high-performance liquid chromatography method with fluorescence detection. The pharmacokinetic analysis was performed using a non-compartmental approach. DNX was quantifiable from 5 min to 168 h after i.v. and i.m. administrations at an identical dosage in both turtle types. No statistical differences were found in the pharmacokinetic parameters between green sea and hawksbill sea turtles. The long elimination half-life value of DNX obtained in green sea (35 h) and hawksbill sea (30.21 h) turtles was consistent with the quite large volume of distribution and the slow clearance rate. The high values of absolute bioavailability (87%-94%) should be advantageous for clinical use of DNX in sea turtles. According to the pharmacokinetic-pharmacodynamic surrogate (AUC_0-24 /MIC > 125), DNX is predicted to have antibacterial success for disease caused by bacteria with MIC < 0.04 µg/ml.

Detection of Chlamydial DNA from Mediterranean Loggerhead Sea Turtles in Southern Italy

Chlamydiae are obligate intracellular bacteria that include pathogens of human and veterinary importance. Several reptiles were reported to host chlamydial agents, but pathogenicity in these animals still needs clarification. Given that only one report of chlamydiosis was described in sea turtles, and that chlamydiae might also be detected in hosts without clinical signs, the current study examined asymptomatic Mediterranean loggerhead sea turtles for the presence of chlamydial DNA. Twenty loggerhead sea turtles, rehabilitated at the Marine Turtle Research Centre (Portici, Italy), were examined collecting ocular-conjunctival, oropharyngeal and nasal swabs. Samples were processed through quantitative and conventional PCR analyses to identify Chlamydiales and Chlamydiaceae, with particular attention to C. pecorum, C. pneumoniae, C. psittaci, and C. trachomatis. Although it was not possible to determine the species of chlamydiae involved, the detection of chlamydial DNA from the collected samples suggests that these microorganisms might act as opportunistic pathogens, and underlines the role of sea turtles as potential carriers. This study highlights the presence of chlamydial agents in sea turtles, and encourages further research to fully characterize these microorganisms, in order to improve the management of the health and conservation of these endangered species, and prevent potential zoonotic implications.

Antibiotic Resistance and Virulence Profiles of Gram-Negative Bacteria Isolated from Loggerhead Sea Turtles (Caretta caretta) of the Island of Maio, Cape Verde

Previous studies revealed high levels of antimicrobial resistance (AMR) in loggerhead sea turtles (Caretta caretta), describing this species as prime reservoir of antimicrobial-resistant bacteria. This study aimed to characterise, for the first time, the AMR and virulence profiles of Gram-negative bacteria isolated from 33 nesting loggerhead turtles of the island of Maio, Cape Verde. Cloacal, oral, and egg content swab samples (n = 99) were collected and analysed using conventional bacteriological techniques. Shewanella putrefaciens, Morganella morganii, and Vibrio alginolyticus were isolated from the samples under study. The isolates obtained from this loggerhead subpopulation (North-East Atlantic) revealed lower levels of AMR, compared with the results of studies performed in other subpopulations (e.g., Mediterranean). However, the detection of resistance to carbapenems and multiple antimicrobial resistance indices higher than 0.20, raises concern about the potential association of these animals to points of high antimicrobial exposure. Furthermore, virulence phenotypic characterisation revealed that the isolates presented complex virulence profiles, including the ability to produce biofilms. Finally, due to their pathogenic potential, and considering the evidence of illegal consumption of turtle-related products on the island of Maio, the identified bacteria may represent a significant threat to public health.

Antibiotic-Resistant Bacteria in Green Turtle (Chelonia mydas) Rearing Seawater

Simple Summary

The Sea Turtle Conservation Center of Thailand (STCCT) has conducted an early intervention program for conservation and faced high mortality rates due to bacterial diseases. Our previous investigation of juvenile turtle carcasses and sea water in the turtle hold tanks implied an association between bacterial isolates in rearing water and infection in captive turtles. In this study, for a management plan of juvenile sea turtles with bacterial infection, we monitored antibiotic resistance of bacteria in seawater from juvenile green turtle holding tanks at STCCT in three periods: January 2015 to April 2016, January to April 2018, and January to April 2019. The results clearly indicated that numbers of resistant bacteria and antibiotics were increased. Assessment of resistance against ten antibiotics revealed high prevalence of antibiotic-resistant bacteria to the beta-lactam class (ampicillin, penicillin, and cefazolin), whereas low resistant isolate numbers were found to aminoglycosides. From the results of this study, we suggest that antibiotic-resistant bacterial assessment in sea turtle rearing seawater will provide important information for the treatment of bacteria-infected sea turtles in husbandry.

Abstract

Antibiotic resistance of microorganisms is a serious health problem for both humans and animals. Infection of these bacteria may result in therapy failure, leading to high mortality rates. During an early intervention program process, the Sea Turtle Conservation Center of Thailand (STCCT) has faced high mortality rates due to bacterial infection. Previously, investigation of juvenile turtle carcasses found etiological agents in tissue lesions. Further determination of sea water in the turtle holding tanks revealed a prevalence of these causative agents in water samples, implying association of bacterial isolates in rearing water and infection in captive turtles. In this study, we examined the antibiotic resistance of bacteria in seawater from the turtle holding tank for a management plan of juvenile turtles with bacterial infection. The examination was carried out in three periods: 2015 to 2016, 2018, and 2019. The highest isolate numbers were resistant to beta-lactam, whilst low aminoglycoside resistance rates were observed. No gentamicin-resistant isolate was detected. Seventy-nine isolates (71.17%) were resistant to at least one antibiotic. Consideration of resistant bacterial and antibiotic numbers over three sampling periods indicated increased risk of antibiotic-resistant bacteria to sea turtle health. Essentially, this study emphasizes the importance of antibiotic-resistant bacterial assessment in rearing seawater for sea turtle husbandry.

Postmortem investigations on leatherback sea turtles (Dermochelys coriacea) stranded in the Canary Islands (Spain) (1998-2017): Evidence of anthropogenic impacts

Opportunities for postmortem studies on leatherback sea turtles (Dermochelys coriacea) are infrequent due to their predominantly pelagic life history. In this study, the pathological findings and causes of mortality of 13 leatherback turtles stranded in the Canary Islands, Spain, from 1998 to 2017, are described. In addition, concentrations of Se, As, Cd, Pb, Hg, 15 rare earth elements (REE) and other 4 minor elements (ME), 41 persistent organic pollutants, and 16 polycyclic aromatic hydrocarbons in hepatic samples from 5 leatherbacks were determined. 84.62% of the turtles died possibly due to anthropogenic causes (entanglement/fishing interaction - 46.15%; boat strike - 23.07%; plastic ingestion - 15.38%). Although Se, As, and Cd were found at higher hepatic concentrations than those reported for leatherbacks from other locations, no acute lesions were detected. This is the first report of exposure to REE-ME in sea turtles. Organic contaminant hepatic concentrations were generally low or undetectable.

Antimicrobial-resistance profiles of gram-negative bacteria isolated from green turtles (Chelonia mydas) in Taiwan

The green turtle (Chelonia mydas) is listed as a globally endangered species and is vulnerable to anthropogenic threats, including environmental pollution. This study investigated the antimicrobial resistance of Gram-negative bacteria isolated from wild green turtles admitted to a sea turtle rehabilitation center in Taiwan. For this investigation, cloacal and nasal swab samples were collected from 28 green turtles between 2018 and 2020, from which a total of 47 Gram-negative bacterial isolates were identified. Among these, Vibrio spp. were the most dominant isolate (31.91%), and 89.36% of the 47 isolates showed resistance to at least one of 18 antimicrobial agents tested. Isolates resistant to one (6.38%), two (8.51%), and multiple (74.47%) antimicrobials were observed. The antimicrobial agents to which isolates showed the greatest resistance were penicillin (74.47%), followed by spiramycin, amoxicillin, and cephalexin. The antimicrobial-resistance profiles identified in this study provide useful information for the clinical treatment of sea turtles in rehabilitation facilities. The results of our study also imply that wild green turtles may be exposed to polluting effluents containing antimicrobials when the turtles traverse migratory corridors or forage in feeding habitats. To benefit sea turtle conservation, future research should focus on (1) how to prevent pollution from antimicrobials in major green turtle activity areas and (2) identifying sources of antimicrobial-resistant bacterial strains in coastal waters of Taiwan.

Health assessment of wild speckled dwarf tortoises, CHERSOBIUS SIGNATUS

BACKGROUND

In free-ranging reptile populations, bacterial, fungal, viral and parasitic pathogens may affect hosts through impairment in movements, thermoregulation, reproduction, survival, and population dynamics. The speckled dwarf tortoise (Chersobius [Homopus] signatus) is a threatened species that is mostly restricted to the Succulent Karoo biome in South Africa, and little information on pathogens of this species is available yet. We derived baseline parameters for five males and five females that were captured to genetically enhance a conservation breeding program in Europe. Upon collection of the tortoises, ticks were removed and identified. Immediately upon arrival in Europe, ocular, nasal, oral and cloacal swabs were taken for viral, bacteriological and mycological examinations. Fecal samples were collected before and 1 month after fenbendazole treatment, and analyzed for parasites. A panel of PCR, aiming to detect herpesviruses, adenoviruses and iridoviruses, was carried out.

RESULTS

Samples were negative for viruses, while bacteriological examination yielded detectable growth in 82.5% of the swabs with a mean load of 16 × 107 ± 61 × 108 colony forming units (CFU) per swab, representing 34 bacterial species. Cloacal and oral swabs yielded higher detectable growth loads than nasal and ocular swabs, but no differences between sexes were observed. Fungi and yeasts (mean load 5 × 103 ± 13 × 103 CFU/swab) were detected in 25% of the swabs. All pre-treatment fecal samples were positive for oxyurid eggs, ranging from 200 to 2400 eggs per gram of feces, whereas after the treatment a significantly reduced egg count (90-100% reduction) was found in seven out of 10 individuals. One remaining individual showed 29% reduction, and two others had increased egg counts. In five tortoises, Nycthocterus spp. and coccidian oocysts were also identified. Soft ticks were identified as Ornithodoros savignyi.

CONCLUSIONS

Our baseline data from clinically healthy individuals will help future studies to interpret prevalences of microorganisms in speckled dwarf tortoise populations. The study population did not appear immediately threatened by current parasite presence.

Colocolic Intussusception Associated with Octangium sp. (Digenea: Microscaphidiidae) in a Green Sea Turtle Chelonia mydas

Reports of intussusception in sea turtles are generally linked to marine debris ingestion; therefore, only a few cases of the disease are associated with parasitic infestations. The objective of this study was to describe the necropsy findings of the first reported case of colocolic intussusception in a green sea turtle Chelonia mydas, associated with the helminth Octangium sp. A juvenile female green sea turtle, which was registered and rescued by the team from the Cetaceans Project of Costa Branca, State University of Rio Grande do Norte, was examined. The animal died 1 d after being treated and was immediately submitted for necropsy. Our findings indicated that parasitic infestation by Octangium sp. in the green sea turtle caused intussusception and consequently led to the animal's death. Early diagnosis and surgical correction are fundamental for a good prognosis and, consequently, for successful rehabilitation of marine species.

Plastic pollution threat in Africa: current status and implications for aquatic ecosystem health

Rapid population growth and poor waste management practice are among the main drivers of plastic pollution in modern times, thus making Africa a hotspot for plastic pollution both now and in the future. This study is a review of plastic pollution reports from the African aquatic environment with regard to causes, current status, toxicological implications and implications for ecosystem services. A total of 59 plastic pollution studies from 1987 to September 2020 were reviewed. They comprised 15 from North Africa (NA) (Algeria, Egypt, Morocco and Tunisia), six from East Africa (EA) (Ethiopia, Kenya, Tanzania and Uganda), 13 from West Africa (WA) (Ghana, Guinea-Bissau, Mauritania and Nigeria), and 25 studies from Southern Africa (SA) (South Africa). This shows that plastic pollution studies in Africa, according to the sub-regions, are in the order: SA > NA > WA > EA. High human population in the basins of African large aquatic systems is identified as the greatest driver enhancing plastic surge in the aquatic environment. The occurrence of plastics was mostly reported in the estuarine/marine environment (42 studies) compared to the freshwater environment (only 17 studies). Plastics have also been reported in the three compartments of the aquatic environment: water column, benthic sediment and animals. Zooplankton, annelids, molluscs, insects, fishes and birds were reported as bioindicators of plastic ingestion in the inland and coastal waters of Africa. Polyethylene, polyethylene terephthalate (polyester) and polypropylene were the common plastic polymers observed in the African aquatic environment. In situ toxicological implications of the ingested plastic polymers were not reported in any of the studies. However, reports from laboratory-controlled experiments showed that these polymers are deleterious to aquatic animal health. More research efforts need to delineate the plastic pollution status of the East, West and North of Africa. Furthermore, such studies are required to identify the plastic polymers and in situ ecotoxicological impacts of plastics on both animal and human health.

Anatomic Interactive Atlas of the Loggerhead Sea Turtle (Caretta caretta) Head

Simple Summary

Because several diseases have been reported affecting the head of sea turtles, accurate anatomic knowledge of this body part is necessary. We provide an open access, anatomic, interactive atlas of the head of the loggerhead sea turtle (Caretta caretta), to facilitate anatomic learning using osteology, gross dissection, and computed tomography (CT) images. Using segmentation and visualization software, relevant anatomic structures were identified and colored in all images, and a computer atlas was developed. This atlas, composed of 55 images, provides an interactive anatomic resource for veterinarians, biologists, researchers, and students involved in loggerhead sea turtle conservation.

Abstract

The head of the sea turtle is susceptible to congenital, developmental, traumatic, and infectious disorders. An accurate interpretation and thorough understanding of the anatomy of this region could be useful for veterinary practice on sea turtles. The purpose of this study was to develop an interactive two-dimensional (2D) atlas viewing software of the head of the loggerhead sea turtle (Caretta caretta) using images obtained via osteology, gross dissections, and computed tomography (CT). The atlas is composed of 10 osteology, 13 gross dissection, 10 sagittal multiplanar reconstructed CT (bone and soft tissue kernels), and 22 transverse CT (bone and soft tissue windows) images. All images were segmented and colored using ITK-SNAP software. The visualization and image assessment were performed using the Unity 3D platform to facilitate the development of interactive content in 2D. This atlas can be useful as an interactive anatomic resource for assessment of the head of loggerhead sea turtles.

Plasma proteomics of green turtles (Chelonia mydas) reveals pathway shifts and potential biomarker candidates associated with health and disease

Evaluating sea turtle health can be challenging due to an incomplete understanding of pathophysiologic responses in these species. Proteome characterization of clinical plasma samples can provide insights into disease progression and prospective biomarker targets. A TMT-10-plex-LC-MS/MS platform was used to characterize the plasma proteome of five, juvenile, green turtles (Chelonia mydas) and compare qualitative and quantitative protein changes during moribund and recovered states. The 10 plasma samples yielded a total of 670 unique proteins. Using ≥1.2-fold change in protein abundance as a benchmark for physiologic upregulation or downregulation, 233 (34.8%) were differentially regulated in at least one turtle between moribund and recovered states. Forty-six proteins (6.9%) were differentially regulated in all five turtles with two proteins (0.3%) demonstrating a statistically significant change. A principle component analysis showed protein abundance loosely clustered between moribund samples or recovered samples and for turtles that presented with trauma (n = 3) or as intestinal floaters (n = 2). Gene Ontology terms demonstrated that moribund samples were represented by a higher number of proteins associated with blood coagulation, adaptive immune responses and acute phase response, while recovered turtle samples included a relatively higher number of proteins associated with metabolic processes and response to nutrients. Abundance levels of 48 proteins (7.2%) in moribund samples significantly correlated with total protein, albumin and/or globulin levels quantified by biochemical analysis. Differentially regulated proteins identified with immunologic and physiologic functions are discussed for their possible role in the green turtle pathophysiologic response and for their potential use as diagnostic biomarkers. These findings enhance our ability to interpret sea turtle health and further progress conservation, research and rehabilitation programs for these ecologically important species.

Disease risk analysis in sea turtles: A baseline study to inform conservation efforts

The impact of a range of different threats has resulted in the listing of six out of seven sea turtle species on the IUCN Red List of endangered species. Disease risk analysis (DRA) tools are designed to provide objective, repeatable and documented assessment of the disease risks for a population and measures to reduce these risks through management options. To the best of our knowledge, DRAs have not previously been published for sea turtles, although disease is reported to contribute to sea turtle population decline. Here, a comprehensive list of health hazards is provided for all seven species of sea turtles. The possible risk these hazards pose to the health of sea turtles were assessed and "One Health" aspects of interacting with sea turtles were also investigated. The risk assessment was undertaken in collaboration with more than 30 experts in the field including veterinarians, microbiologists, social scientists, epidemiologists and stakeholders, in the form of two international workshops and one local workshop. The general finding of the DRA was the distinct lack of knowledge regarding a link between the presence of pathogens and diseases manifestation in sea turtles. A higher rate of disease in immunocompromised individuals was repeatedly reported and a possible link between immunosuppression and environmental contaminants as a result of anthropogenic influences was suggested. Society based conservation initiatives and as a result the cultural and social aspect of interacting with sea turtles appeared to need more attention and research. A risk management workshop was carried out to acquire the insights of local policy makers about management options for the risks relevant to Queensland and the options were evaluated considering their feasibility and effectiveness. The sea turtle DRA presented here, is a structured guide for future risk assessments to be used in specific scenarios such as translocation and head-starting programs.

Ocular ultrasonography of sea turtles

BACKGROUND

Environmental changes contribute to the development of ophthalmic diseases in sea turtles, but information on their eye biometrics is scarce. The aim of this study was to describe ophthalmic ultrasonographic features of four different sea turtle species; Caretta caretta (Loggerhead turtle; n = 10), Chelonia mydas (Green turtle; n = 8), Eretmochelys imbricata (Hawksbill turtle; n = 8) and Lepidochelys olivacea (Olive ridley; n = 6) under human care. Corneal thickness, scleral ossicle width and thickness, anterior chamber depth, axial length of the lens, vitreous chamber depth and axial globe length were measured by B-mode sonography with a linear transducer. Carapace size and animal weight were recorded. A sonographic description of the eye structures was established.

RESULTS

The four species presented an ovate eyeball, a relatively thin cornea, and a small-sized lens positioned rostrally in the eye bulb, near the cornea, resulting in a shallow anterior chamber. The scleral ossicles did not prevent the evaluation of intraocular structures, even with a rotated eye or closed eyelids; image formation beyond the ossicles and measurements of all proposed structures were possible. B-mode sonography was easily performed in all animals studied. The sonographic characteristics of the eye were similar among the four species. Since there was a correlation between the size of the eye structures and the size of the individual, especially its carapace size, the differences found between E. imbricata and Caretta caretta are believed to be due to their overall difference in size.

CONCLUSIONS

Sonography is a valuable tool in ophthalmic evaluation of these species. Only minor differences were found between the species in this study, reinforcing their phylogenetic proximity and their similar functions and habitats.

Hook-shaped enterolith and secondary cachexia in a free-living grey nurse shark (Carcharias taurus, Rafinesque 1810)

The carcass of a critically endangered, juvenile female grey nurse shark (Carcharias taurus, Rafinesque 1810) was recovered from a south‐eastern Australian beach and subjected to necropsy. The 1.98‐m‐long shark exhibited advanced cachexia with its total weight (19.0 kg) and liver weight (0.37 kg) reduced by 60% and 89%, respectively, compared with a healthy individual of the same length. Marked tissue decomposition was evident preventing histopathology and identification of a definitive cause of death. At necropsy, the abdominal organs were abnormally displaced and showed marked reductions in size compared with a healthy individual of the same size. Importantly, a hook‐shaped enterolith (HSE), with a rough surface and cream in colour, was found within the spiral valve of the intestine and is to the authors’ knowledge, the first description of such in any marine animal. X‐ray diffractometry showed that the HSE comprised the minerals monohydrocalcite (Ca[CO₃].H₂O; ~70 wt%) and struvite (Mg [NH₄] [PO₄]. [H₂O]₆; ~30 wt%). A CT scan showed concentric lamellate concretions around a 7/o offset J‐hook that formed the nidus of the HSE. Nylon fishing line attached to the hook exited the HSE and was evident in the abdominal cavity through a perforation in the intestinal wall where the posterior intestinal artery merges. The most parsimonious reconstruction of events leading to enterolithiasis and secondary cachexia in this shark was the consumption of a hooked fish and subsequent hook migration causing perforations of the cardiac stomach wall followed by the thin, muscular wall of the apposed, sub‐adjacent intestine.

Pathological Findings in Leatherback Sea Turtles (Dermochelys coriacea) During an Unusual Mortality Event in São Paulo, Brazil, in 2016

The leatherback sea turtle (LST; Dermochelys coriacea) is highly migratory and is primarily distributed throughout tropical and subtropical regions. The LST populations found in Brazil are critically endangered. An unusual mortality event occurred between August and November 2016 with 23 LSTs stranded along a 100 km coastal segment in Iguape, Ilha Comprida and Ilha do Cardoso in southern São Paulo state. This study investigated the pathological findings and most likely causes of death of 10 LSTs. Male (n = 9) and adult (n = 9) animals predominated. All but one animal was in good body condition and all were found dead. The most prevalent gross findings were suggestive of bycatch, namely cutaneous erosions, abrasions and/or lacerations around the neck and flippers (n = 9), generalized congestion (n = 8) and pulmonary oedema (n = 6). Other prevalent gross findings were: cutaneous epibiosis by Stomatolepas elegans (n = 7); ileocecal diverticulitis (n = 7); distal oesophagitis (n = 5); and fibrinous coelomitis (n = 5). Microscopically, the most prevalent findings were: hepatic melanomacrophage centre hypertrophy or hyperplasia (n = 9); interstitial pneumonia (n = 8); multisystemic congestion (n = 6); pulmonary oedema with or without aspirated material (n = 5); adrenal coccidiosis (n = 5) with variable multiorgan involvement; and multiorgan bacterial disease (n = 5). Five animals had food ingesta (cnidarians, crustaceans) in the oesophagus or stomach; only one had evident plastic foreign bodies. Asphyxia due to entanglement in nets was the most frequently identified cause of death (n = 8); a cause of death was not identified in two animals. Our findings provide evidence of the severe negative impact of entanglement in fishing nets in LSTs, raising concerns for conservation. These findings also contribute to knowledge of the pathology of LSTs in South American populations.

Antibiotic Resistance of Gram-Negative Bacteria from Wild Captured Loggerhead Sea Turtles

Sea turtles have been proposed as health indicators of marine habitats and carriers of antibiotic-resistant bacterial strains, for their longevity and migratory lifestyle. Up to now, a few studies evaluated the antibacterial resistant flora of Mediterranean loggerhead sea turtles (Caretta caretta) and most of them were carried out on stranded or recovered animals. In this study, the isolation and the antibiotic resistance profile of 90 Gram negative bacteria from cloacal swabs of 33 Mediterranean wild captured loggerhead sea turtles are described. Among sea turtles found in their foraging sites, 23 were in good health and 10 needed recovery for different health problems (hereafter named weak). Isolated cloacal bacteria belonged mainly to Enterobacteriaceae (59%), Shewanellaceae (31%) and Vibrionaceae families (5%). Although slight differences in the bacterial composition, healthy and weak sea turtles shared antibiotic-resistant strains. In total, 74 strains were endowed with one or multi resistance (up to five different drugs) phenotypes, mainly towards ampicillin (~70%) or sulfamethoxazole/trimethoprim (more than 30%). Hence, our results confirmed the presence of antibiotic-resistant strains also in healthy marine animals and the role of the loggerhead sea turtles in spreading antibiotic-resistant bacteria.

Epidemiology of blood flukes (Digenea: Spirorchiidae) in sea turtles from Tyrrhenian and Adriatic Seas, off Italy

Background

The Spirorchiidae is a family of blood flukes parasitizing turtles. Spirorchiids may cause a wide range of inflammatory reactions in the vascular system of their host being frequently implicated with stranding and death of sea turtles worldwide. Recent studies revealed the presence of two spirorchiid species in the Mediterranean basin. Our study presents comparative epidemiological data of spirorchiid infections in loggerhead turtles (Caretta caretta) stranded during an eight-year period from Adriatic and Tyrrhenian Seas, and the first report of Neospirorchis Neogen-11 in a green turtle (Chelonia mydas).

Methods

We screened a total of 319 carcasses of loggerhead turtles stranded from January 2011 to December 2018 along the Tyrrhenian coast (n = 111) and the north-western Adriatic coast (n = 208) of Italy using traditional (copromicroscopy and histopathology) and molecular assays. Three green turtles from the Tyrrhenian coast were also included in the study.

Results

A total of 56 (17.5%) loggerhead turtles and one green turtle (33.3%) were found to be infected with spirorchiid flukes. Amplification, sequencing of the ITS2 region of the ribosomal RNA gene cluster and BLAST analysis confirmed the presence of Hapalotrema mistroides and Neospirorchis Neogen-11 in 51 (16.0%) and 24 (7.5%) loggerhead turtles, respectively, and Neospirorchis Neogen-11 in an infected green turtle. Differences in prevalence of infection between the two sampling areas were found.

Conclusions

The risk of spirorchiid infection in the Tyrrhenian Sea is lower than in the Adriatic Sea and in general the risk of infection in the Mediterranean is lower than in other geographical locations. Differences in the prevalence of infection between the two sampling areas were related to the differences of regional habitats supporting different abundance of spirorchiid intermediate hosts. A systematic monitoring to evaluate the progress of the infection is recommended, as well as studies on the occurrence and distribution of spirorchiid species from other Mediterranean areas.

Gastric lesions in free-living sea turtles: An underestimated disease that reflects the health of the ecosystem

Free-living marine turtles are constantly exposed to aggression factors and the gastrointestinal tract is one of the main gateways of entry. The objective of this study was to identify, and describe the anatomopathological alterations in the stomach of free-living marine turtles found dead on the beaches of the Microrregião dos Lagos, Rio de Janeiro, Brazil. Twenty-two sea turtles were necropsied, and stomach fragments were collected, fixed, and processed routinely. The presence of gastritis, parasitism, and adaptative morphological alteration of the cells were evaluated in a microscopic analysis. Descriptive statistics and Fisher's exact test were performed. Of the samples, 59.1% had stomach hyperemia. Microscopically, gastritis was found in 86.4% of cases, parasitism in 72.7%, and adaptive morphological alteration in 59.1%. There was an association between the presence of cellular adaptive morphological alteration and chronic inflammation. This the first report to describe the adaptive morphological changes observed in the stomach cells. The chronicity of the lesions was due to continuous aggressions to the tissue, with parasitism, garbage ingestion, and environmental pollutants as possible causes. The results obtained in this study demonstrate that the chronicity of the stomach lesions is due to continuous aggressions to this tissue, and the irritating factors have environmental origin, such as parasites, garbage, and toxic pollutants, including heavy metals, which are ingested by free-living sea turtles. This article demonstrates that stomach injuries in free-living marine turtles are frequent, severe, and possibly underdiagnosed; these lesions reflect the diseased ecosystem in which those animals live.

Twenty-three Years of Sea Turtle Stranding/ bycatch Research in Taiwan

Coastal sea turtle stranding and bycatch are common phenomena worldwide and have received more attention in recent years. They are caused by both natural and anthropogenic factors. One thousand and seventy-two turtles were reported to be victims of these phenomena from March 1997 to November 2019 in Taiwan. Number of stranding/bycatch were variable and infrequent for the first 14 years, but increased each year after 2012 and peaked in 2019 with 217 cases. Most turtles were juveniles to subadults. All five of Taiwan's species were reported in stranding and bycatch records, and the green turtle was reported the most common. The main reported seasons lasted from winter to spring, when the weather changes dramatically. The sex ratio (female: male) ranged from 7 in the hawksbill turtle to 0.7 in the olive ridley, with an average of 2.4 for all species. Green turtles were the dominant stranded species, and more loggerhead turtles were by-caught. The hotspots were the towns of Dougou and Tochen in Yilan County, and Gongliao District in New Taipei City, located in NE coast of Taiwan respectively. Stranding was the more common of the two phenomena reported, and 80% of all stranded turtles were subadult green turtles. Eighty percent of all stranded/bycaught turtles were dead. Pond-nets were the fishing gear that accounted for the most bycatch, and captured mainly living young and subadult green turtles as well as subadult loggerhead turtles. The hotspots for bycatch were the towns of Dongou and Tochen in Yilan County. The Coast Guard and concerned citizen were the main sources of reports. This is the first study to analyze the long-term stranding/bycatch of sea turtles in Taiwan.

Lesions Observed Post Mortem in Post-hatchling Loggerhead Sea Turtles (Caretta caretta) from a Head Start Programme

Head start programmes are ex-situ conservation procedures consisting of the captive rearing of sea turtle hatchlings for several months in order to avoid high mortality rates in the first year of life. Studies of the diseases of hatchling and post-hatchling turtles belonging to these programmes are scarce. We describe the gross and histological lesions found in 78 post-hatchling loggerhead sea turtles (Caretta caretta) that died during captive rearing in the conservation programme of the Cape Verde-Canary Islands, initiated with 113 hatchlings. The main organ systems affected were respiratory (57.69%), integumentary (41.02%) and digestive (41.02%), affecting 94.87% of the animals. Other less frequently affected organ systems were cardiovascular (3.85%), excretory (3.85%), muscular (2.56%) and reproductive (1.28%). The most common lesions were different types of dermatitis (41.02%), mainly ulcerative and/or heterophilic ulcerative dermatitis; these lesions were compatible with a traumatic origin caused by biting and subsequent infection with gram-positive cocci. Purulent and/or fibrinonecrotizing rhinitis associated with mixed populations of bacteria were commonly detected respiratory lesions (21.79%). Acute interstitial pneumonia was the most common form of pneumonia diagnosed (20.51%). Fibrinonecrotizing stomatitis associated with sparse gram-negative rods was the most common digestive tract lesion (29.49%). A possible explanation for the high mortality rate (88.50%) observed in this study could be the occurrence of a decrease in water temperature during the growth phase of the turtles. Despite the limitations caused by an absence of microbiological studies, the survey provides useful information on the lesions found in post-hatchling loggerhead turtles from this head start programme. In addition to maintaining water temperature above 20°C, attention must be paid to lesions that can easily be detected, such as dermatitis, rhinitis and stomatitis.

The Occurrence of Vibrionaceae, Staphylococcaceae, and Enterobacteriaceae in Green Turtle Chelonia mydas Rearing Seawater

In this study, levels of Vibrionaceae, Staphylococcaceae, and Enterobacteriaceae were observed in seawater from juvenile green turtle Chelonia mydas rearing tanks and in the incoming coastal seawater (the water supply). Bacterial loads were compared between the incoming coastal seawater and two different rearing conditions: in cement tanks at a low stocking density and in fiberglass tanks at a high stocking density. The total bacterial counts in seawater from fiberglass tanks were statistically greater than those in cement tanks. The nonlactose and lactose fermenting enterobacteria, tellurite-reducing bacteria, and total plate counts in water from all rearing containers were greater than those in coastal seaweater by a logarithmic fold change of 2--3. Differences in bacterial population structure of the incoming coastal seawater and rearing water were also addressed. The results from biochemical identification of 344 isolates revealed that the bacteria that were commonly found in water samples were Citrobacter spp., Enterobacteria spp., Edwardsiella spp., Staphylococcus spp., Staphylococcus aureus, Photobacterium spp., Vibrio alginolyticus, and Vibrio spp. Conclusively, the microbiological monitoring of rearing water provides important and essential information on the management of aquatic animal health and husbandry.

Loggerhead sea turtles as sentinels in the western Mediterranean: antibiotic resistance and environment-related modifications of Gram-negative bacteria

Sea turtles possess relevant characteristics to serve as sentinel species for monitoring the health of marine ecosystems, which is currently threatened. This study examined 35 loggerhead turtles from the western Mediterranean, focusing on the oral and cloacal prevalence of aerobic Gram-negative bacteria, their antibiotic resistance and the influence of several variables linked both to the animal and the environment (i.e. estimated life stage; area, season and cause of recovery; plastic ingestion). Conventional bacteriology methods led to the isolation of bacterial families commonly regarded as opportunistic pathogens (i.e. Aeromonadaceae; Enterobacteriaceae; Pseudomonadaceae; Shewanellaceae; Vibrionaceae), but pointing out sea turtles as carriers of potential zoonotic agents. The high rates of antibiotic resistance, here detected, raise important concerns on the dissemination of this phenomenon in marine environments. Moreover, several of the examined variables showed a significant influence on the prevalence of bacterial families, strengthening the role of sea turtles as mirrors of their ecosystems.

Mortality associated with ingestion of sea urchins in loggerhead sea turtles (Caretta caretta): A case series

Aims

The aims of this study were: a) to describe the pathological and laboratory findings in a case series of stranding and mortality associated with ingestion of large amounts of sea urchins in loggerhead turtles (Caretta caretta), and b) to alert veterinarians and biologists involved in sea turtle conservation of this cause of stranding and/or death.

Methods

The six loggerheads studied were stranded on the coasts of Gran Canaria, Canary Islands, Spain, between 2008 and 2015. Post mortem studies included pathological, microbiological, and sea urchin species identification procedures.

Results

All turtles showed severe intestinal impaction caused by large amounts of sea urchins, mainly affecting the colon and the caudal half of the small intestine. Histologically, severe focal fibrinonecrotic enteritis was diagnosed in two turtles. In the remaining turtles, lesions ranged from mild desquamation of the intestinal epithelium to severe congestion of the blood vessels of lamina propria, submucosa, muscular and serosa, and edema. Vibrio sp. was isolated from the spleen and intestinal mucosa of a loggerhead in which focal fibrinonecrotic enteritis had been diagnosed. In five turtles, all the remains were fragments from long-spined sea urchins (Diadema africanum); the last turtle contained a mixture of long-spined sea urchin (90%) and purple sea urchin (Sphaerechinus granularis) (10%) remains.

Conclusions

Although the prevalence of this cause of stranding was low (< 1.6%) compared to other mortality causes, continued overfishing and anthropogenic climate change could increase its incidence. Intestinal impaction with large amounts of sea urchins should be included in the differential diagnosis of gastrointestinal diseases in sea turtles, and the possible toxic effect of some sea urchin species on sea turtles should also be investigated.

Fatal Photobacterium damselae-induced enteritis in a leatherback turtle Dermochelys coriacea

Stranded leatherback turtle Dermochelys coriacea complete pathology reports are rare, and the cause of mortality is difficult to determine in many cases. We conducted a complete pathological study of a stranded leatherback turtle from the western Mediterranean. The main finding was a fibrino-necrotizing enteritis with associated bacteria which were identified as Photobacterium damselae subsp. damselae according to biochemical and phenotypical characteristics. This report provides evidence of the pathogenic effect of this bacterium in wild sea turtles.

A novel host-adapted strain of Salmonella Typhimurium causes renal disease in olive ridley turtles (Lepidochelys olivacea) in the Pacific

Salmonella spp. are frequently shed by wildlife including turtles, but S. enterica subsp. enterica serovar Typhimurium or lesions associated with Salmonella are rare in turtles. Between 1996 and 2016, we necropsied 127 apparently healthy pelagic olive ridley turtles (Lepidochelys olivacea) that died from drowning bycatch in fisheries and 44 live or freshly dead stranded turtles from the west coast of North and Central America and Hawaii. Seven percent (9/127) of pelagic and 47% (21/44) of stranded turtles had renal granulomas associated with S. Typhimurium. Stranded animals were 12 times more likely than pelagic animals to have Salmonella-induced nephritis suggesting that Salmonella may have been a contributing cause of stranding. S. Typhimurium was the only Salmonella serovar detected in L. olivacea, and phylogenetic analysis from whole genome sequencing showed that the isolates from L. olivacea formed a single clade distinct from other S. Typhimurium. Molecular clock analysis revealed that this novel clade may have originated as recently as a few decades ago. The phylogenetic lineage leading to this group is enriched for non-synonymous changes within the genomic area of Salmonella pathogenicity island 1 suggesting that these genes are important for host adaptation.

NEUROLOGIC AND COMPUTED TOMOGRAPHY FINDINGS IN SEA TURTLES WITH HISTORY OF TRAUMATIC INJURY

Boat strikes have been widely documented as a major cause of anthropogenic trauma and mortality in sea turtles. Axial trauma in these species involves the head and/or carapace and may cause severe damage to the nervous and pulmonary systems. The aims of this study were to develop an updated protocol for neurologic examinations in sea turtles, to describe computed tomography (CT) findings in sea turtles with sustained trauma, and to associate CT findings with neurologic status in sea turtles with and without traumatic injury. Ten sea turtles were examined, six green (Chelonia mydas) and four loggerhead (Caretta caretta) turtles: seven underwent neurologic and CT examinations, two had CT examinations only, and one had a neurologic examination only. The updated neurologic examination protocol was considered useful in differentiating normal from abnormal neurologic status, however some of these tests remain unreliable in sea turtles. Sea turtles with no history of trauma were found to have normal carapace shape, vertebral column, and neurologic status. Sea turtles with history of traumatic injury (more than 10 years prior to examination) had findings dependent on trauma site. Those with head trauma had variable presentations dependent on location of injury; while those with carapace trauma had varying degrees of kyphosis, lordosis, and scoliosis of the carapace, vertebral fractures, and paraparesis. Kyphosis of the carapace was associated with vertebral fractures detected on CT; however, the severity of vertebral abnormalities was not associated with the severity of neurologic deficits. These findings suggest that a combination of neurologic and CT examination may be beneficial in determining clinical significance of carapace deformation and associated neurologic deficits in sea turtles with traumatic injury.

Orthopedics in Reptiles and Amphibians

Musculoskeletal disorders are a common cause for presentation of reptiles and amphibians to the veterinarian. A clinical approach to orthopedic cases starts with a thorough history and review of husbandry, and identification of any underlying or concomitant disease. Medical management is indicated for pathologic fractures. Traumatic fractures may require surgical intervention. Stabilization options include external coaptation and/or external and internal fixation. Special considerations must be given to shell fractures in chelonians. Many techniques used in mammalian practice can be applied to reptiles and amphibians, although some species may require prolonged healing times by comparison.

Microplastics in the marine environment: Current trends in environmental pollution and mechanisms of toxicological profile

The global plastics production has increased from 1.5 million tons in the 1950s to 335 million tons in 2016, with plastics discharged into virtually all components of the environment. Plastics rarely biodegrade but through different processes they fragment into microplastics and nanoplastics, which have been reported as ubiquitous pollutants in all marine environments worldwide. This study is a review of trend in marine plastic pollution with focus on the current toxicological consequences. Microplastics are capable of absorbing organic contaminants, metals and pathogens from the environment into organisms. This exacerbates its toxicological profile as they interact to induced greater toxic effects. Early studies focused on the accumulation of plastics in the marine environment, entanglement of and ingestions by marine vertebrates, with seabirds used as bioindicators. Entanglement in plastic debris increases asphyxiation through drowning, restrict feeding but increases starvation, skin abrasions and skeletal injuries. Plastic ingestion causes blockage of the guts which may cause injury of the gut lining, morbidity and mortality. Small sizes of the microplastics enhance their translocation across the gastro-intestinal membranes via endocytosis-like mechanisms and distribution into tissues and organs. While in biological systems, microplastics increase dysregulation of gene expression required for the control of oxidative stress and activating the expression of nuclear factor E2-related factor (Nrf) signaling pathway in marine vertebrates and invertebrates. These alterations are responsible for microplastics induction of oxidative stress, immunological responses, genomic instability, disruption of endocrine system, neurotoxicity, reproductive abnormities, embryotoxicity and trans-generational toxicity. It is possible that the toxicological effects of microplastics will continue beyond 2020 the timeline for its ending by world environmental groups. Considering that most countries in African and Asia (major contributors of global plastic pollutions) are yet to come to terms with the enormity of microplastic pollution. Hence, majority of countries from these regions are yet to reduce, re-use or re-circle plastic materials to enhance its abatement.

Spirorchiidiasis in marine turtles: the current state of knowledge

Blood flukes of the family Spirorchiidae are important disease agents in marine turtles. The family is near cosmopolitan in distribution. Twenty-nine marine species across 10 genera are currently recognized, but taxonomic problems remain and it is likely that more species will be discovered. Spirorchiids infect the circulatory system, where they and their eggs cause a range of inflammatory lesions. Infection is sometimes implicated in the death of the turtle. In some regions, prevalence in stranded turtles is close to 100%. Knowledge of life cycles, important for control and epidemiological studies, has proven elusive until recently, when the first intermediate host identifications were made. Recent molecular studies of eggs and adult worms indicate that a considerable level of intrageneric and intraspecific diversity exists. The characterization of this diversity is likely to be of importance in exploring parasite taxonomy and ecology, unravelling life cycles, identifying the differential pathogenicity of genotypes and species, and developing antemortem diagnostic tools, all of which are major priorities for future spirorchiid research. Diagnosis to date has been reliant on copromicroscopy or necropsy, which both have significant limitations. The current lack of reliable antemortem diagnostic options is a roadblock to determining the true prevalence and epidemiology of spirorchiidiasis and the development of effective treatment regimes.

Primary Multicentric Pulmonary Low-grade Fibromyxoid Sarcoma and Chelonid Alphaherpesvirus 5 Detection in a Leatherback Sea Turtle (Dermochelys coriacea)

We describe the gross, microscopical, histochemical and immunohistochemical features of a sclerosing pneumopathic disease process resembling primary multicentric pulmonary low-grade fibromyxoid sarcoma in a juvenile female leatherback sea turtle (Dermochelys coriacea). The animal was fresh, presented in good body condition and stranded dead in Aracaju, Sergipe state, Brazil, in September, 2017. Grossly, the lungs were enlarged bilaterally and the parenchyma was replaced by large, coalescing, white, firm masses that extended into the bronchi and bronchioles and to the pleura. Microscopically, these masses consisted of paucicellular populations of well-differentiated, spindle-shaped fibroblasts with low pleomorphism and low mitotic count, but tissue invasion. Abundant collagen in compact areas merged with peripheral fibromyxoid foci and inflamed stroma. Antibodies specific for cytokeratins AE1/AE3 and smooth muscle actin (SMA) labelled pneumocytes lining the remaining distorted alveoli and the hypertrophied and hyperplastic bronchial muscles, respectively. Tumour cells were negative for SMA; neither neoplastic nor normal tissues cross-reacted with antibodies specific for vimentin or Ki67. Chelonid alphaherpesvirus 5 (ChHV5) polymerase chain reaction analysis from formalin-fixed, paraffin wax-embedded lung tissue sections amplified a 450 base pair fragment of DNA-polymerase (UL30 region) that had 100% homology to sequences previously detected in green sea turtles (Chelonia mydas) on the Brazilian coast. Enterocolitis was a concomitant condition that likely caused morbidity in this case. These findings contribute to the body of knowledge on sea turtle health and expand the known geographical range for ChHV5 in the southern hemisphere.

Phacoemulsification cataract surgery in the loggerhead turtle (Caretta caretta): surgical technique and outcomes in 10 cases

Cataract removal using phacoemulsification was performed in 10 loggerhead turtles being rehabilitated after stranding. All turtles had significant systemic abnormalities and had cataracts either at the time of rescue or developed them during rehabilitation. Surgical difficulties encountered included an extremely soft globe that did not allow for a partial thickness corneal incision, incomplete topical anesthesia of the ocular surface with proparacaine, inability to dilate the pupil pharmacologically, a markedly shallow anterior chamber, a thick posterior capsular plaque in most cases, and difficulty creating a watertight closure with sutures. Minimal to no intraocular inflammation was seen in all cases following surgery, but all cases in which corneal sutures were used developed a marked inflammatory reaction surrounding the sutures and appeared uncomfortable until sutures were removed or sloughed. All turtles appeared to have improved vision following surgery and were eventually released. Two turtles were re-encountered a year or more after release. Both showed signs of normal growth and the ability to capture prey in the wild. This report documents successful outcomes associated with cataract surgery in loggerhead turtles, but also presents significant surgical challenges that should be taken into account before attempting this procedure in this species.