Worldwide occurrence of feline hemoplasma infections in wild felid species.
(25/97)
While hemoplasma infections in domestic cats are well studied, almost no information is available on their occurrence in wild felids. The aims of the present study were to investigate wild felid species as possible reservoirs of feline hemoplasmas and the molecular characterization of the hemoplasma isolates. Blood samples from the following 257 wild felids were analyzed: 35 Iberian lynxes from Spain, 36 Eurasian lynxes from Switzerland, 31 European wildcats from France, 45 lions from Tanzania, and 110 Brazilian wild felids, including 12 wild felid species kept in zoos and one free-ranging ocelot. Using real-time PCR, feline hemoplasmas were detected in samples of the following species: Iberian lynx, Eurasian lynx, European wildcat, lion, puma, oncilla, Geoffroy's cat, margay, and ocelot. "Candidatus Mycoplasma haemominutum" was the most common feline hemoplasma in Iberian lynxes, Eurasian lynxes, Serengeti lions, and Brazilian wild felids, whereas "Candidatus Mycoplasma turicensis" was the most prevalent in European wildcats; hemoplasma coinfections were frequently observed. Hemoplasma infection was associated with species and free-ranging status of the felids in all animals and with feline leukemia virus provirus-positive status in European wildcats. Phylogenetic analyses of the 16S rRNA and the partial RNase P gene revealed that most hemoplasma isolates exhibit high sequence identities to domestic cat-derived isolates, although some isolates form different subclusters within the phylogenetic tree. In conclusion, 9 out of 15 wild felid species from three different continents were found to be infected with feline hemoplasmas. The effect of feline hemoplasma infections on wild felid populations needs to be further investigated. (+info)
Bayesian estimation of sequence damage in ancient DNA.
(26/97)
DNA extracted from archaeological and paleontological remains is usually damaged by biochemical processes postmortem. Some of these processes lead to changes in the structure of the DNA molecule, which can result in the incorporation of incorrect nucleotides during polymerase chain reaction. These base misincorporations, or miscoding lesions, can lead to the inclusion of spurious additional mutations in ancient DNA (aDNA) data sets. This has the potential to affect the outcome of phylogenetic and population genetic analyses, including estimates of mutation rates and genetic diversity. We present a novel model, termed the delta model, which estimates the amount of damage in DNA data and accounts for its effects in a Bayesian phylogenetic framework. The ability of the delta model to estimate damage is first investigated using a simulation study. The model is then applied to 13 aDNA data sets. The amount of damage in these data sets is shown to be significant but low (about 1 damaged base per 750 nt), suggesting that precautions for limiting the influence of damaged sites, such as cloning and enzymatic treatment, are worthwhile. The results also suggest that relatively high rates of mutation previously estimated from aDNA data are not entirely an artifact of sequence damage and are likely to be due to other factors such as the persistence of transient polymorphisms. The delta model appears to be particularly useful for placing upper credibility limits on the amount of sequence damage in an alignment, and this capacity might be beneficial for future aDNA studies or for the estimation of sequencing errors in modern DNA. (+info)
The canine distemper epidemic in Serengeti: are lions victims of a new highly virulent canine distemper virus strain, or is pathogen circulation stochasticity to blame?
(27/97)
In the year 1994, the Serengeti lion population was decimated by a canine distemper disease outbreak. Retrospective investigations showed that this host population had already been in contact with the pathogen in 1981 without any detected sign of disease. As an alternative to the virus mutation hypothesis to explain this difference in virulences observed in 1981 and 1994, we propose a novel mechanism of disease emergence based on variation in population immunity. We use a stochastic model to show that stochastic fluctuations in pathogen circulation, owing to a low probability of virus transmission from its reservoir to the target host and thereby resulting in variations in the global immunity level of the target host population, can explain the observations made in Serengeti. This mechanism may also be involved in other infectious disease emergences or re-emergences. (+info)
Seroprevalence of selected infectious agents in a free-ranging, low-density lion population in the Central Kalahari Game Reserves in Botswana.
(28/97)
Twenty-one free-ranging Central Kalahari lions (Panthera leo) exhibited a high prevalence rate of feline herpesvirus (100%) and feline immunodeficiency virus (71.4%). Canine distemper virus and feline calicivirus occurred with a low prevalence. All individuals tested negative for feline coronavirus, feline parvovirus, feline leukemia virus, Ehrlichia canis, and Anaplasma phagocytophilum. (+info)
Molecular detection of "Candidatus Mycoplasma haemominutum" in a lion (Panthera leo) from a Brazilian zoological garden.
(29/97)
Although Mycoplasma haemofelis and "Candidatus Mycoplasma haemominutum" infections have been reported in wild cats from United States, their presence among native and captive wild cats in Brazil is still unknown. A 12 year old healthy male lion (Panthera leo) from the Zoological Garden of Curitiba, Brazil was anesthetized for transportation and dental evaluation. A blood sample was obtained for a complete blood cell count (CBC) and PCR analysis. DNA was extracted and fragments of Mycoplasma haemofelis and "Candidatus Mycoplasma haemominutum" 16S ribosomal RNA gene were amplified in PCR assays. CBC results were within reference intervals. A weak band of 192 pb for "Candidatus Mycoplasma haemominutum" was observed, and no band was amplified from Mycoplasma haemofelis reaction. A weak PCR band associated with normal CBC results and without visible parasitemia or clinical signs may suggest a chronic subclinical infection with "Candidatus Mycoplasma haemominutum". The lack of clinical signs may also represent the low pathogenicity of this organism; however, it is noteworthy that immune suppression caused by management and/or corticoids treatment may induce parasitemia and anemia in this animal. This detection suggests further studies in captive wild cats in Brazilian Zoological Gardens. (+info)
Supermodeled sabercat, predatory behavior in Smilodon fatalis revealed by high-resolution 3D computer simulation.
(30/97)
The American sabercat Smilodon fatalis is among the most charismatic of fossil carnivores. Despite broad agreement that its extraordinary anatomy reflects unique hunting techniques, after >150 years of study, many questions remain concerning its predatory behavior. Were the "sabers" used to take down large prey? Were prey killed with an eviscerating bite to the abdomen? Was its bite powerful or weak compared with that of modern big cats? Here we quantitatively assess the sabercat's biomechanical performance using the most detailed computer reconstructions yet developed for the vertebrate skull. Our results demonstrate that bite force driven by jaw muscles was relatively weak in S. fatalis, one-third that of a lion (Panthera leo) of comparable size, and its skull was poorly optimized to resist the extrinsic loadings generated by struggling prey. Its skull is better optimized for bites on restrained prey where the bite is augmented by force from the cervical musculature. We conclude that prey were brought to ground and restrained before a killing bite, driven in large part by powerful cervical musculature. Because large prey is easier to restrain if its head is secured, the killing bite was most likely directed to the neck. We suggest that the more powerful jaw muscles of P. leo may be required for extended, asphyxiating bites and that the relatively low bite forces in S. fatalis might reflect its ability to kill large prey more quickly, avoiding the need for prolonged bites. (+info)
Peribiliary cysts associated with severe liver disease: a previously unrecognized tumor in a lion (Panthera leo).
(31/97)
A 13-year-old male lion (Panthera leo) from Dae Jeon Zoo, Republic of Korea, presented with clinical signs of lethargy and anorexia. Despite treatment with antibiotics and fluid therapy, the lion died 6 days after initial presentation. Postmortem examination revealed multiple masses measuring 5-10 cm in diameter and cysts throughout the liver. A diagnosis of spontaneous peribiliary cysts was made on the basis of microscopic lesions as well as special staining and immunohistochemical characteristics. Histologically, the neoplasm was surrounded and composed of compact collagenous tissue. The inner cystic single layer resembled biliary mucosa and was composed of cuboidal or flattened epithelial lining that was strongly immunopositive for cytokeratin AE1/AE3. This layer was surrounded by fibrous tissue that stained blue by Masson's trichrome staining. Given the presence of multiple organized cysts in the liver, the lesion was consistent with peribiliary cysts. To the authors' knowledge, this is the first report of peribiliary cysts in an animal. (+info)
High-grade mucoepidermoid carcinoma of the mandibular salivary gland in a lion (Panthera leo).
(32/97)