Cholesterol,corneal lipidosis,and xanthomatosis in amphibians

Many captive amphibians have high serum or plasma cholesterol and concomittant lesions such as corneal lipidosis and xanthomas. The underlying cause of this disorder is unknown, but it is likely that a diet high in cholesterol plays a role. The metabolism of lipids in healthy amphibians remains poorly documented, which makes it challenging to interpret the findings in affected specimens. Affected amphibians should be maintained on a low-cholesterol diet and fed sparingly, and their captive environment modified to provide an optimal temperature gradient for thermoregulation.     

两栖动物肝簇虫、锥虫的研究进展

肝簇虫和锥虫是通过昆虫媒介传播的两栖动物极易感染的两种血液寄生虫,且混合感染率极高,可导致两栖类种群数量下降,甚至灭绝。肝簇虫和锥虫分布范围广泛,脊椎动物多为易感动物,感染动物机体后,依靠吸收血液中的营养物质大量繁殖,释放大量毒素破坏红细胞和免疫系统,增加机体对其他传染性疾病的感染机率。另外肝簇虫和锥虫的传播媒介广泛存在于自然界,因此在给两栖动物带来严重危害的同时,也具有传播给人类的风险。本文针对两栖动物肝簇虫和锥虫形态特征、生活史、易感动物和地理分布、及其危害进行概述,以期唤起同行研究人员的重视,为血液寄生虫的相关研究提供参考。     

Toll样受体信号通路在两栖类中的研究进展

两栖类处于脊椎动物由水生向陆生进化的过渡阶段,进化地位重要。近年来因疾病的爆发、生境破碎化、环境污染、紫外辐射增加、人为过度捕捉和生物入侵等诸多因素引起的全球范围内两栖类种群数量锐减已引起人们的广泛关注。Toll样受体(Toll-like receptor,TLR)家族是一类从线虫到哺乳动物普遍存在的高度保守的模式识别受体(PRRs),可以识别侵入机体病原体的病原相关分子模式(PAMPs),是两栖类先天性免疫防御系统的重要组成部分。本文结合近些年国内外对两栖类TLRs的研究对两栖类TLRs结构特征、进化特点、在两栖类发育早期的差异表达特征和两栖类TLRs信号通路中相关分子的表达研究进行概述。目前对于两栖类TLRs的研究发现两栖类TLRs兼具鱼类和哺乳类TLRs的特征,并在从鱼类到两栖类到哺乳类的进化过程中,TLRs家族部分成员如TLR2的配体识别功能可能发生了一定程度的特化;在两栖类早期发育阶段,获得性免疫不够完善,以TLRs为主的先天免疫防御系统在抵御病原体的侵袭方面发挥了重要作用;在特定病原菌和病毒的胁迫下,可能激活了TLRs下游不同的途径参与两栖类对病原体的免疫应答反应。     

Wild‐Caught and Farm‐Reared Amphibians are Important Reservoirs of Salmonella,A Study in North‐East Thailand

The role of amphibians as Salmonella reservoirs has not been as well studied as in reptiles, where the literature is abundant. Recent outbreaks of salmonellosis associated with exotic pet frogs have occurred in United States. Frog farming and wild frog harvesting have increased the international trade in these species. This necessitates a better understanding of the risk of salmonellosis transmission from amphibians to humans. We explored the presence of Salmonella in amphibians (frogs and toads) in Thailand, where farmed and wild frogs as well as toads are present. These live animals are easily found in the local markets and are used as food. Exportation of frog meat from Thailand is common. During March–June 2014, ninety‐seven frogs were collected from several habitats, including frog farms, urban areas and protected natural areas. The collected amphibians were tested for the presence of Salmonella. The overall prevalence of Salmonella was 69.07% (90.00% in farm animals, 0% in urban area animals and 44.83% in protected area animals). Eight serovars of Salmonella were isolated: subsp. diarizonae ser. 50:k:z, Hvittingfoss, Muenchen, Newport, Stanley, Thompson, Panama and Wandsworth. Six of the identified serovars, Hvittingfoss, Newport, Panama, Stanley, Thompson and Wandsworth, have been detected in humans in Thailand. According to our results, amphibians are reservoirs of Salmonella and can be a public health concern when used as a source of protein for humans.     

Effect of season and temperature on mortality in amphibians due to chytridiomycosis

OBJECTIVE: To investigate the distribution and incidence of chytridiomycosis in eastern Australian frogs and to examine the effects of temperature on this disease. DESIGN: A pathological survey and a transmission experiment were conducted. PROCEDURE: Diagnostic pathology examinations were performed on free-living and captive, ill and dead amphibians collected opportunistically from eastern Australia between October 1993 and December 2000. We conducted a transmission experiment in the laboratory to investigate the effects of temperature: eight great barred frogs (Mixophyes fasciolatus) exposed to zoospores of Batrachochytrium dendrobatidis and six unexposed frogs were housed individually in each of three rooms held at 17 degrees C, 23 degrees C and 27 degrees C. RESULTS: Chytridiomycosis was the cause of death or morbidity for 133 (55.2%) of 241 free-living amphibians and for 66 (58.4%) of 113 captive amphibians. This disease occurred in 34 amphibian species, was widespread around the eastern seaboard of Australia and affected amphibians in a variety of habitats at high and low altitudes on or between the Great Dividing Range and the coast. The incidence of chytridiomycosis was higher in winter, with 53% of wild frogs from Queensland and New South Wales dying in July and August. Other diseases were much less common and were detected mostly in spring and summer. In experimental infections, lower temperatures enhanced the pathogenicity of B. dendrobatidis in M. fasciolatus. All 16 frogs exposed to B. dendrobatidis at 17 degrees C and 23 degrees C died, whereas 4 of 8 frogs exposed at 27 degrees C survived. However, the time until death for the frogs that died at 27 degrees C was shorter than at the lower temperatures. Infections in survivors were eliminated by 98 days. CONCLUSION: Chytridiomycosis is a major cause of mortality in free-living and captive amphibians in Australia and mortality rate increases at lower temperatures.     

两栖爬行动物的异地保护

中国是世界上动植物种类最丰富的国家之一，但国内对野生两栖爬行动物的掠夺性利用还在发展；国内野生两栖爬行动物资源在这种疯狂的掠夺下已经接近枯竭，多数物种处于濒危状态。动物园作为野生动物异地保护的重要场所，饲养繁殖野生动物的最终目的是实现濒危物种的再引入，恢复野外种群数量．出于以上目的，动物园中两栖爬行动物的饲养管理方式有别于爬虫爱好者单纯的满足对宠物的要求和增殖牟利追求。这种区别不仅表现在选择动物种类方面，更多的体现在丰容概念的引入及工作方法的应用：营造合理的饲养环境、饲养环境小气候的周期性变化、设施的丰容、群体的调整、食物及供给方式的变化、对繁殖行为的鼓励等。这些丰容手段对保持两栖爬行动物的自然行为，从而保证动物的野外生存能力具有重要作用．     

Chytridiomycosis in an aquarium collection of frogs: diagnosis, treatment, and control

The introduction of a new group of dendrobatid frogs to an established captive amphibian collection was followed by several acute mortalities in both resident and introduced frog populations. Chytridiomycosis, caused by Batrachochytrium dendrobatidis, was diagnosed by histology in two of the dead frogs. Following the diagnosis, all amphibians were moved to a specially made quarantine room with strict handling protocols and treated with itraconazole. Frogs, being terrestrial amphibians, were treated with itraconazole (Sporanox, 10 mg/ml) at 0.01% in 0.6% saline in a 5-min bath for 11 consecutive days. Axolotls (Ambystoma mexicanum) and Kaup's caecilians (Potymotyphlus kaupii), being aquatic amphibians, were treated with itraconazole administered directly in their primary tank water to achieve a concentration of 0.01% for 30 min every 5 days for four treatments. Itraconazole was removed from the tank water after 30 min by high-rate-of-flow activated charcoal filters. The treatment and quarantine procedures were successful in eradicating the disease. The few amphibian mortalities that occurred in the 18 mo after the start of the treatment have been histologically negative for the presence of chytrid fungi. The collection is now considered free of chytridiomycosis.     

Designing environments for captive amphibians and reptiles.

Environments for captive amphibians and reptiles play a critical role in their long-term health, and veterinarians need to be informed of the requirements of various species when evaluating the causes of disease. Enclosure size, substrates, landscaping, heating, lighting, and relative humidity are the areas of primary concern when designing vivaria. Two different approaches are used when keeping amphibians and reptiles, depending primarily on the size of the species maintained: a laboratory animal-type system and naturalistic vivarium system. The latter places more emphasis on simulating essential elements of natural habitats and on aesthetic appeal of the display.     

Amphibian renal disease.

Amphibians by nature have an intimate connection with the aquatic environment at some stage of development and fight an osmotic battle due to the influx of water. Many amphibians have acquired a more terrestrial existence at later stages of development and consequently have physiologic adaptations to conserve moisture. Renal adaptations have allowed amphibians successfully to bridge the gap between aqueous and terrestrial habitats. The kidneys, skin,and, in many amphibian species, the urinary bladder play key roles in fluid homeostasis. Renal impairment may be responsible for the clinical manifestation of disease, morbidity, and mortality.     

安溪县陆生野生动物资源状况及区系研究

1998、1999年福建省安溪县林业局开展了鸟类、兽类、两栖爬行类资源调查,基本摸清了安溪县范围内陆生野生动物资源状况。通过区系研究,表明安溪县的鸟类、兽类、两栖爬行动物在动物地理分布上的特征以东洋界的组成成分为主,在动物的二级区系组成上鸟兽类以华南区成分为主,两栖爬行类以华中、华南区成分为主。动物区系中华中、华南区成分的混杂现象也较明显,表现出在动物地理分布上的过渡性、渗透性。     

Pentastomiasis and other parasitic zoonoses from reptiles and amphibians

Reptiles are growing in popularity as pets.The colonization of reptiles and amphibians by parasites and the resulting disease conditions are the most common problems seen in captive animals.This review focuses on pentastomiasis and sparganosis, important parasitic zoonoses of reptiles and amphibians, respectively, and free living-amoebae. Humans are suitable accidental hosts for some pentastomid species (particularly Armillifer and Porocephalus). In geographical areas with special ethnics, such as in West and Central Africa, and East Asia, 8-45% of the human population can be affected. Usually the larvae are coincidentally found during abdominal surgeries. However, fatalities have been described. Extreme caution is necessary when handling infected reptiles. Ocular or cerebral sparganosis is not uncommonly found in humans in East Asia. This disease is caused by spargana, tapeworm larvae (plerocercoids) of Spirometra sp. The infection occurs when uncooked meat from reptiles or amphibians is applied to wounds or eyes and the parasites migrate directly to human tissue, or by consumption of contaminated food or water. As a consequence of the reptile's predatory behaviour, the full spectrum of endo- and ectoparasites from potential prey animals can be found as transiting parasites in the intestinal tract, e. g. Hymenolepis nana, Cryptosporidium (C.) muris, C parvum or Capillaria hepatica. Occasionally, free-living amoebae are also found in reptile faeces (Acanthamoeba, Naegleria, Hartmanella, Vahlkampfia or Echinamoeba sp.).     

Fish, amphibian, and reptile analgesia.

Pain perception and appropriate behavioral responses are important for survival. The conservation of the opioid ligand and receptor suggests evolution of opioid receptors mediating antinociception throughout vertebrate phylogeny. Fish, amphibians, and reptiles have appropriate neurologic components, display the appropriate behavior in response to a painful stimulus, and possess antinociceptive mechanisms to modulate pain. Because pain perception in these species is therefore likely to be analogous to that of mammals, invasive and painful procedures should always be accompanied by appropriate analgesia and anesthesia. Although specific doses have not been established in clinical trials, clinicians should attempt to provide lower vertebrates with appropriate analgesia during painful procedures. Further experimental and clinical investigations are necessary to expand the current veterinary literature in the area of pain and analgesia in lower vertebrates such as fish, amphibians, and reptiles.     

Housing situation of small animals in Swiss pet shops

This study investigates the situation regarding housing of small animals in Swiss pet shops. Data of 92 pet shops were collected with a questionnaire. On average 813 fish, 52.5 invertebrates, 32.2 small mammals, 26.9 birds, 8.9 reptiles and 2.7 amphibians were offered for sale per pet shop. Small mammals, birds and reptiles were mainly obtained from Swiss breeders, while fish and amphibians were almost exclusively purchased from foreign providers. The housing systems which were sold differed from those in which the animals were kept in the shop. This may be misleading to the future pet owners and may lead to faulty husbandry. Animals on reserve were often kept in different housing systems than those in the pet shop. Sick animals were usually treated or killed by the pet shop owners. The killing methods varied between the various species.     

Anesthetic Considerations for Amphibians

The popularity of amphibians in research, zoological exhibits, and as pets is on the rise. With this increased popularity comes a need for veterinarians to develop methods for managing these animals for various diagnostic and surgical procedures. For many of these procedures, the provision of anesthesia is a must. Fortunately, there are a number of different anesthetics available to the veterinary clinician for anesthetizing amphibians, including tricaine methanesulfonate, clove oil, propofol, isoflurane, and ketamine. In addition to the variety of anesthetics at our disposal, there is also a wider range of methods for delivering the anesthetics than are generally available for higher vertebrates, including immersion, topical, and intracoelomic routes of delivery. The purpose of this article is to review the different methods that can be used to successfully manage an amphibian patient through an anesthetic event.     

Nematode and ciliate nasal infection in captive archey's frogs (Leiopelma archeyi)

Archey's frogs (Leiopelma archeyi) are first on the list of evolutionarily distinct and globally endangered (EDGE) amphibians. Captive breeding is an important strategy for protection of the species, but programs are hampered by a lack of information on diseases present in wild and captive populations. Two novel nematodes (Koerneria sp. and Rhabditis sp.) were found separately in four captive Archey's frogs showing clinical signs of hemorrhagic purulent nasal discharge and weight loss. One of these frogs also had a novel protozoal infection (Tetrahymena) in the nasal cavity. Koerneria, Rhabditis, and Tetrahymena have not previously been reported in amphibians in New Zealand. One frog was treated successfully with oral moxidectin at 0.4 mg/kg for the nematode infection and topical metronidazole at 10 mg/kg for the protozoal infection. The clinical signs abated only after both infections were cleared. The second frog died before treatment could be established. The third and fourth frogs were found dead.     

崇明陈家镇示范绿地两栖类调查

2007年4月至2008年7月,对崇明陈家镇示范绿地两栖类进行调查,根据两栖类资源和生境的特点,选取了17处调查地点。共记录到泽蛙、中华蟾蜍、黑斑蛙、金线蛙等两栖类4种,共计546只,其中泽蛙329只,占总数的61%,优势明显。在不同栖息生境中浅滩观测到两栖类种类最多,4种两栖类都观测到,在林带观测到的两栖类有266只,占总数的49%,数量最多,不同生境两栖类分布差异显著。不同水域中沟浜分布的两栖类有4种,达到全部观测4种记录,同时沟浜观测到两栖类303只,占总数的55%,数量最多,两栖类分布受水域性质影响显著。     

Can carotenoids mediate the potentially harmful effects of ultraviolet light in Silurana (Xenopus) tropicalis larvae?

Amphibians have recently experienced unprecedented declines in the wild, the causes of which are often difficult to mitigate. This has increased the importance of ex situ conservation; however, long‐term maintenance and breeding of amphibians in captivity often has limited success. In vertebrates, vitamin D is required for calcium homeostasis and is produced endogenously in skin exposed to ultraviolet (UV) light; however, UV light can be harmful to amphibians in some instances. Carotenoids are dietary pigments that may provide protection from UV light. The aim of this study was to assess the protective capability of carotenoids against the potentially harmful effects of UV light in Silurana (=Xenopus) tropicalis larvae raised in an enhanced or limited UV environment. Tadpole survival and the size and developmental stage reached by the end of the study period were measured. Carotenoids had a significantly positive effect on developmental rate in both UV‐limited and UV‐enhanced environments. Larvae in an enhanced UV environment were significantly larger than those raised under a limited UV environment, irrespective of diet. Carotenoid‐fed larvae tended to have increased survival in relation to those raised without carotenoids, but only in a limited UV environment. Carotenoids appear to provide little protection against UV light in this case. The role of carotenoids in amphibian health has not previously been studied. We show that carotenoid availability significantly influences development and may increase survival in S. (X.) tropicalis larvae. This finding may have important implications for recommendations made on the nutrition of amphibians in captivity.     

Fungal diseases of amphibians: an overview.

Clinicians should be familiar with the most common fungal diseases of amphibians. Because lesions in mycotic diseases are nonspecific, a diagnosis cannot be established solely on the basis of clinical presentation. Bacterial, mycobacterial, chlamydial, and parasitic infections, and toxic or environmental conditions may mimic mycotic disease to various extents. Furthermore, mycoses may be masked by overwhelming secondary bacterial infection and therefore remain undiagnosed. Skin scrapings, impression smears, biopsies, and fungal culture are all useful tools in confirming or dismissing a diagnosis of mycosis. Whenever possible, an effort should be made to forward samples and biopsies for culture to appropriate laboratories. Providing the laboratory with a tentative etiologic diagnosis may allow for specific selection of more specific agars and culture conditions and maximize the chances of recovering the fungus from lesions. Identification to species level should also be encouraged, if progress is to be made in the understanding of mycoses in amphibians. The morphology of an isolate should be consistent with the microscopic features of the fungus in histological sections of affected tissues, if it is to be firmly incriminated as the cause of disease. A complete necropsy should be conducted on animals that die or are found dead, and, ideally, isolates from confirmed cases of fungal infection should be deposited in scientific collections, so that they are available for later studies. In addendum, readers should be aware that there is recent evidence to suggest that at least some published cases of amphibian basidiobolomycosis were in fact cases of chytridiomycosis [38], and therefore the validity of basidiobolomycosis as a disease entity in amphibians may be revisited in the years to come.     

Congenital Malformations of the Vertebral Column in Ancient Amphibians

Temnospondyls, the largest group of Palaeozoic and Mesozoic amphibians, primitively possess rhachitomous vertebrae with multipartite centra (consisting of one horse‐shoe‐shaped inter‐ and paired pleurocentra). In a group of temnospondyls, the stereospondyls, the intercentra became pronounced and disc‐like, whereas the pleurocentra were reduced. We report the presence of congenital vertebral malformations (hemi, wedge and block vertebrae) in Permian and Triassic temnospondyls, showing that defects of formation and segmentation in the tetrapod vertebral column represent a fundamental failure of somitogenesis that can be followed throughout tetrapod evolution. This is irrespective of the type of affected vertebra, that is, rhachitomous or stereospondylous, and all components of the vertebra can be involved (intercentrum, pleurocentrum and neural arch), either together or independently on their own. This is the oldest known occurrence of wedge vertebra and congenital block vertebra described in fossil tetrapods. The frequency of vertebral congenital malformations in amphibians appears unchanged from the Holocene.     

山东省济宁市野生动物救护现状及分析

济宁市野生动物救护中心在2017—2019年日常救护的86只野生动物,分属16目26科40种,本地动物种类占92.5%。在野生动物救护种类和数量上以鸟类最多(79.1%),其次为兽类、两栖类、爬行类;救助成活率爬行类(100%)和鸟类成(86.7%)较高,两栖类(75%)及兽类成活率(76%)较低。本文对野生动物救护的种类、数量、伤病原因、级别进行了分析,讨论了鸟类救护方法,提出了野生动物救护合理化建议,对野生动物救护和生物多样性保护意义重大。