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Health assessment of free-ranging anacondas (Eunectes murinus) in Venezuela

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... The H:L ratio is less variable than the actual number of circulating leukocytes (Gross and Siegel, 1983). Calle et al. (1994) found a correlation among increased H:L ratios, chronic stress, and decreased body condition over time. Unlike corticosterone levels which change in response to acute stressors, such as restraint (Sapolsky et al., 2000;Wingfield, 1994), H:L ratios are relatively resistant to acute stress (Calle et al. 1994;Gross and Siegel, 1983;Hansen and Damgaard, 1993;Vleck et al., 2000). ...
... Calle et al. (1994) found a correlation among increased H:L ratios, chronic stress, and decreased body condition over time. Unlike corticosterone levels which change in response to acute stressors, such as restraint (Sapolsky et al., 2000;Wingfield, 1994), H:L ratios are relatively resistant to acute stress (Calle et al. 1994;Gross and Siegel, 1983;Hansen and Damgaard, 1993;Vleck et al., 2000). This makes the H:L ratio more suitable for investigations of long-term influences on body condition. ...
... While adult American alligators have no natural enemies, adult spectacled caimans have a number of predators, such as jaguar, cougar, and green anaconda (Calle et al. 1994;Scognamillo et al. 2003). Should juveniles of the two species already exhibit behavioral predispositions similar to those of adults, we could expect them to show differential behaviors in our conditions; e.g., alligators might be more explorative. ...
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Behavioral predispositions are innate tendencies of animals to behave in a given way without the input of learning. They increase survival chances and, due to environmental and ecological challenges, may vary substantially even between closely related taxa. These differences are likely to be especially pronounced in long-lived species like crocodilians. This order is particularly relevant for comparative cognition due to its phylogenetic proximity to birds. Here we compared early life behavioral predispositions in two Alligatoridae species. We exposed American alligator and spectacled caiman hatchlings to three different novel situations: a novel object, a novel environment that was open and a novel environment with a shelter. This was then repeated a week later. During exposure to the novel environments, alligators moved around more and explored a larger range of the arena than the caimans. When exposed to the novel object, the alligators reduced the mean distance to the novel object in the second phase, while the caimans further increased it, indicating diametrically opposite ontogenetic development in behavioral predispositions. Although all crocodilian hatchlings face comparable challenges, e.g., high predation pressure, the effectiveness of parental protection might explain the observed pattern. American alligators are apex predators capable of protecting their offspring against most dangers, whereas adult spectacled caimans are frequently predated themselves. Their distancing behavior might be related to increased predator avoidance and also explain the success of invasive spectacled caimans in the natural habitats of other crocodilians.
... Unfortunately, due to size restrictions, our baseline sample volumes all fell below 1 ml of plasma and all results were returned as <50 ng/ml. Previous literature has reported plasma vitamin A (measured as retinol) concentrations for various squamates and amphibian species, including green iguanas (Iguana iguana, 52-75 ng/ml), eastern indigo snakes (Drymarchon couperi, 9 ng/ml), anacondas (Eunectes murinus, 80 ng/ml), Mississippi gopher frogs (Rana capito servosa, 36-43 ng/ml), marine toads (Bufo marinus, 60 ng/ml), Cuban tree frogs (Osteopilus septentrionalis 83 ng/ml), and Puerto Rican crested toads (Bufo lemur, 130 ng/ml) [25][26][27][30][31][32][33]. ...
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Black soldier fly (BSF) larvae have been marketed as an excellent choice for providing calcium to reptiles without the need of dusting or gut loading. However, previous studies have indicated that they have limited calcium digestibility and are deficient in fat soluble vitamins (A, D3, and E). In this feeding and digestibility trial, 24 adult male leopard geckos were fed one of three diets for 4 months: 1) whole, vitamin A gut loaded larvae; 2) needle pierced, vitamin A gut loaded larvae; or 3) whole, non-gut loaded larvae. Fecal output from the geckos was collected daily and apparent digestibility was calculated for dry matter, protein, fat, and minerals. There were no differences in digestibility coefficients among groups. Most nutrients were well digested by the leopard geckos when compared to previous studies, with the exception of calcium (digestibility co-efficient 43%), as the calcium-rich exoskeleton usually remained intact after passage through the GI tract. Biochemistry profiles revealed possible deficits occurring over time for calcium, sodium, and total protein. In regards to vitamin A digestibility, plasma and liver vitamin A concentrations were significantly higher in the supplemented groups (plasma- gut loaded groups: 33.38 ± 7.11 ng/ml, control group: 25.8 ± 6.72 ng/ml, t = 1.906, p = 0.04; liver- gut loaded groups: 28.67 ± 18.90 μg/g, control group: 14.13 ± 7.41 μg/g, t = 1.951, p = 0.03). While leopard geckos are able to digest most of the nutrients provided by BSF larvae, including those that have been gut loaded, more research needs to be performed to assess whether or not they provide adequate calcium in their non-supplemented form.
... With the exception of B. constrictor and H. carinicaudus, in our study, A. rotundatum infested snakes at lower rates than previously reported. In a study conducted in Venezuela, six specimens of E. murinus were found infested with A. dissimile, but not A. rotundatum (33). In the Northern (34), Midwest (23), and Southern region (35) of Brazil, specimens of E. murinus were found infested by A. dissimile. ...
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The Ixodidae family comprises ticks that are hematophagous ectoparasites and are considered vectors of several hemoparasites from the Anaplasmataceae family and the genus Hepatozoon, Babesia, and Rickettsia. These ectoparasites parasitize domestic and wild animals belonging to several vertebrate groups. Ticks are highly adapted to different biomes and thus possess a wide geographical distribution. In the Brazilian state of Bahia, localized in the Northeast region, there are large rainforest fragments. Studies have rarely been carried out on ticks, and their hemoparasites, that parasitize wild animals in this region. Thus, this study aimed to identify the tick species parasitizing wild animals rescued in rainforest fragments of Bahia and investigate the presence of hemoparasites in tick tissues. During a 2-year period, 238 ticks were collected from 41 wild mammalians, reptiles, and amphibians. These ectoparasites were taxonomically classified according to their morphological characteristics. The ticks identified belonged to five different species from the Ixodidae family: Amblyomma varium, Amblyomma rotundatum, Amblyomma nodosum, Ixodes loricatus, and Rhipicephalus sanguineus. For the first time, an A. rotundatum parasitizing the Mesoclemmys tuberculata turtle was described. PCR assays using DNA extracted from salivary glands or midgut of the ticks were performed to detect specific DNA fragments of hemoparasites from the genus Rickettsia, Ehrlichia, Babesia, Hepatozoon, and from the Anaplasmataceae family. The results showed positive detection of the Rickettsia genus (7.9%), Anaplasmataceae family (15.8%), and Hepatozoon genus (15.8%). Specific DNA from the Ehrlichia and Babesia genera were not detected in these samples. Specific DNA from members of the Anaplasmataceae family was detected in A. varium for the first time. The present work showed that amphibians, reptiles, and mammals from Bahia's Atlantic Forest areparasitized by different tick species, and that these ectoparasites present pathogens in their tissues that impact both humans and animals due to their zoonotic potential.
... have been reported from a number of free-ranging Central American, South American, and Caribbean snake species including free-ranging anaconda from Brazil and Venezuela, Pearl Island boa (Boa constrictor sabogae) from Panama, and boas (B. constrictor and reported as Corallus enydris) from Trinidad (Muller, 1971;Calle et al., 1994;Moravec and Santos, 2009; USNM 1345047 and 1345052). In addition, unidentified Dracunculus nematodes have been recovered from several captive snakes that had been imported from South America including boas (B. ...
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Nematodes are an extremely diverse and speciose group of parasites. Adult dracunculoid nematodes (Superfamily Dracunculoidea) occur in the tissues and serous cavities of mammals, fish, reptiles, amphibians and birds. Of the dracunculid group, perhaps best known is Dracunculus medinensis, the human Guinea Worm. Considerable work has been done on D. medinensis; however recent infections in peri-domestic dogs and the finding of naturally-infected paratenic hosts (previously unreported for D. medinensis) indicate we still have much to learn about these parasites. Furthermore, among eight species in the Old World and six species in the New World there is a lack of general life history knowledge as well as questions on species occurrence, host diversity, and transmission dynamics. Herein, we provide a comprehensive review of the genus Dracunculus, in order of a theoretical evolutionary progression from reptilian to mammalian hosts. Species descriptions, where available, are provided but also show where gaps occur in our knowledge of various species. Additionally, many first reports of Dracunculus spp. were done prior to the development and use of molecular tools. This is especially important for this group of parasites as speciation based on morphology is only applicable to males of the genus, and males, given their size, are notoriously difficult to recover from definitive hosts. Therefore, we also discuss current molecular tools used in the investigation of this group of parasites. Given recent host-switching events, the dracunculids are of increasing importance and require further work to expand our understanding of this genus.
Hematology and biochemistry testing of boas and pythons is a valuable topic for practicing clinicians and researchers alike. This article reviews blood cell morphology (with accompanying images) and reviews the literature for hematologic and biochemical material clinically relevant to the families Boidae and Pythonidae.
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Habitat loss, human persecution, and infectious diseases all threaten declining reptile populations. Lake Erie watersnakes (Nerodia sipedon insularum, LEWS), once classified as an endangered species in part due to human persecution, have recovered to stable population levels but have been observed with a high prevalence of ophidiomycosis. Strategies are needed to mitigate the current disease threat, including assessing overall wellness. Hematologic analysis provides information about the presence of inflammation and infection and thus informs health-based conservation efforts, but has not been previously performed in LEWS. The objective of this study was to evaluate hematologic parameters in LEWS and identify differences based on ophidiomycosis status. Blood was drawn from wild-caught snakes at nine sites in 2018 and 2019 and complete blood counts were performed in 180 individuals. For apparently healthy snakes, packed cell volume was significantly higher in males (median = 32.5%) compared to females (median = 26.5%; P = 0.03). Animals classified as having possible or apparent ophidiomycosis, or those with skin lesions, had a relative azurophilia and lymphopenia compared to individuals classified as negative or Ophidiomyces present, or those without skin lesions (P < 0.01). This is the first study to investigate hematology in a free-ranging population of LEWS and will serve as a baseline for future investigations that aim to improve conservation efforts through population health monitoring.
Chapter
The hematology and clinical chemistry of snakes continue to develop as more research and information are obtained. Reference intervals published for snake species vary widely. Diversity results from individual patient factors (intrinsic and extrinsic), blood collection techniques, laboratory methodology, and environmental parameters. This chapter offers complete information on obtaining samples, performing tests, and interpreting laboratory results in snakes. It emphasizes details on clinical biochemistries, urinalysis, and common laboratory diagnostic tests. Blood samples can often be collected from snakes using manual restraint. Erythrocyte, leukocyte, and thrombocyte counts of snakes are most often determined by hemocytometer techniques as most automated cell counters cannot differentiate between the nucleated thrombocytes, erythrocytes, and leukocytes of reptiles. The stain type and counting methods used may significantly affect cell counts reported in snakes. The clinician should be aware of the methods used to determine cell counts for their patients.
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