Successful establishment and global dispersal of genotype VI avian paramyxovirus serotype 1 after cross species transmission

The evolutionary history of avian paramyxovirus serotype 1 (PMV1), which includes the agents of Newcastle disease (ND), is characterized by a series of strain emergence events since viruses in this family were first recognized in the 1920s. Despite the importance of ND to the poultry industry, little is known about PMV1 strain emergence events and the subsequent dispersal and evolution of new strains. The genotype VI-PMV1 was first identified in the 1980s and has been named pigeon paramyxovirus-1 (PPMV1) because of unusual host specificity with Columbiformes (Collins et al., 1996); it has been responsible for panzootics in both chickens and pigeons during that time. Here, we used evolutionary analyses to characterize the emergence of this contemporary PMV1 lineage. We demonstrate that GVI-PMV1 arose through cross-species transmission events from Galliformes (i.e. chicken) to Columbiformes, and quickly established in pigeon populations. Our studies revealed a close association between the time of viral emergence and panzootic events of this virus. The virus appeared first in Southeastern Europe and quickly spread across the European continent, which became the epicenter for global virus dissemination. With new viral gene sequences, we show that GVI-PMV1 viruses currently circulating in North America resulted from multiple invasion events from Europe, one associated with an exotic European Columbiformes species, and that extant lineages have diversified locally. This study extends our understanding of successful viral emergence subsequent to cross-species transmission and dispersal patterns of newly emerged avian viruses, which may improve surveillance awareness and disease control of this and other important avian pathogens.     

Visual effects of opiates in pigeons

In a psychophysical task that permitted dissociations among sensitivity, overall stimulus control, and bias, pigeons learned to discriminate among stimuli along separate wavelength and luminance dimensions. Subsequent tests followed injections of morphine (1–8 mg/kg) and morphine plus naloxone (3 mg/kg). Morphine decreased sensitivity to both dimensions, and reduced overall control by luminance. These effects were reduced or reversed by naloxone. Morphine's effects appeared more pronounced for luminance than for wavelength stimuli. There were no consistent drug effects on response bias.     

A further look at the binocular visual field of the pigeon (Columba livia)

The binocular visual field of the pigeon, measured ophthalmoscopically, is ovoid in shape. It is 114 degrees in vertical extent and centered and widest (37 degrees) about the eye-beak axis (i.e. the line passing through the straight edge of the beak and the midpoint of a line connecting the centres of the pupils). The area dorsalis projects 10 degrees-15 degrees below the eye-beak axis where the field is 35 degrees wide. The stereotyped peck response of the pigeon entails birds pausing twice. At the first fixation, the image of a grain is on the area dorsalis and at the final fixation the grain is centered within the widest part of the binocular field.     

吐停口服液抗顺铂所致家鸽呕吐的实验研究

目的:观察吐停口服液对顺铂所致家鸽呕吐的作用.方法:采用家鸽腹腔注射顺铂法制造呕吐模型,观察家鸽呕吐次数、呕吐潜伏期.结果:模型组家鸽在连续3 d注射顺铂后均出现剧烈呕吐反应,而吐停口服液高、低剂量组第1 d均未出现呕吐,第2 d、3 d虽有呕吐,但呕吐次数较模型组明显减少,(P＜0.01),呕吐潜伏期延长(高剂量组P＜0.01,低剂量组P＜0.05).结论:吐停口服液对顺铂所致家鸽的呕吐有明显抑制作用.     

Health hazards posed by feral pigeons

A comprehensive literature search of epidemiological studies and reports of transmissions of disease from feral pigeons to humans was performed. There were 176 documented transmissions of illness from feral pigeons to humans reported between 1941 and 2003. Feral pigeons harbored 60 different human pathogenic organisms, but only seven were transmitted to humans. Aerosol transmission accounted for 99.4% of incidents. There was a single report of transmission of Salmonella enterica serotype Kiambu to humans from feral pigeons, and no reports of transmission of Campylobacter spp. The most commonly transmitted pathogens continue to be Chlamydophila psittaci and Cryptococcus neoformans. Although feral pigeons pose sporadic health risks to humans, the risk is very low, even for humans involved in occupations that bring them into close contact with nesting sites. In sharp contrast, the immunocompromised patient may have a nearly 1000-fold greater risk of acquiring mycotic disease from feral pigeons and their excreta than does the general population.     

Somatosensory areas in the telencephalon of the pigeon

Two somatosensory regions in the pigeon's telencephalon were investigated electrophysiologically with recordings of field potentials as well as single- and multi-unit responses which were evoked by electrical stimulation of all four extremities or by feather movements produced with airpuffs or by hand. The outline of both areas, was studied in detail with the use of grid-like recordings of single or multi-units. One somatosensory area is located rostrally in the hyperstriatum accessorium (HA), rostral to the visual "Wulst". A caudal area comprises the medial aspects of two different cell layers: the neostriatum intermedium (NI) and adjacent neostriatum caudale (NC) as well as the overlying hyperstriatum ventrale (HV). The two areas differ considerably in their response characteristics. Field potentials of the NI/NC-HV area were more complex than those of the HA area and their shapes and latencies varied mainly in dependence of the recording site (NI, NC, HV). Multi-unit responses showed strong excitation and short latencies in NI/NC and weak excitation and longer latencies in HV. Both responses and latencies were uniform in the HA area and latencies generally longer than in NI/NC but shorter than in HV. The HA area processes somatosensory information more specifically. Its neurons have relatively small receptive fields which seem to be arranged in a somatotopic order in such a way that rostral parts of the body are represented superficially and caudal parts in deeper layers. In contrast, the NI/NC-HV area was found to be largely multimodal, receiving also auditory and visual information. Neurons in this region have large somatic receptive fields, often including one and sometimes even both sides of the body surface. A somatotopic arrangement could not be recognized. The whole body surface was representated in both areas, but there was a dominance of wing and back receptive fields in the NI/NC-HV area and leg and neck receptive fields in the HA area.     

Failure of interocular transfer in the pigeon (Columba livia).

Pigeons were trained on a modified jumping stand to discriminate a circle from a triangle using only one eye. Testing with the naive eye revealed no evidence of interocular transfer. This failure of transfer was also observed under more stringent testing using reversal learning. The results are discussed in terms of a selective attention model for panoramic vision.     

Changes in pattern discrimination learning induced by visual deprivation in normal and commissurotomized pigeons

Summary The effect of monocular (MD), binocular (BD) and alternating monocular (AMD) deprivation on monocular pattern discrimination learning and interocular transfer was investigated in pigeons reared with intact and sectioned supraoptic decussation (DSO). In BD and AMD animals acquisition and interocular transfer of two different pattern discrimination problems remained as good as in the control animals (CO). Monocularly deprived animals (MDE) required significantly more trials to learn the discriminations through the deprived eye, when it was trained first, and interocular transfer from the deprived to the experienced eye was absent. However, if the experienced eye was trained first (MED), learning with the deprived eye was at least as rapid as with the experienced eye. This indicates positive interocular transfer from the experienced to the deprived eye.Interocular transfer of pattern discriminations was completely blocked by section of the DSO in both adults (DSOad) and newly hatched animals (DSOjuv). The elimination of binocular interaction by commissurotomy from the beginning of the postnatal life failed to produce an impaired pattern discrimination learning in monocularly deprived animals (MD+DSO).The results are discussed in terms of competition between the projections from both eyes in the visual Wulst.     

Characterization of the discriminative stimulus effects of buprenorphine in pigeons

Rationale: The pedunculopontine tegmental nucleus (PPTg) has been implicated in the self-administration of drugs, particularly nicotine, which acts directly through the PPTg in addition to targeting midbrain dopamine neurons. The direct action of nicotine in PPTg may be through GABAergic mechanisms that have been shown to influence nicotine self-administration preferentially compared to cocaine. Objective: The purpose of these experiments was to examine several pharmacological manipulations that alter neuronal activity in the PPTg for their specificity or generality in nicotine versus cocaine reinforcement. Methods and results: Rats trained to self-administer nicotine or cocaine intravenously were prepared with brain microcannulae directed to the PPTg. Intra-PPTg microinfusions of the muscarinic agonist carbachol (0.1–1.0 μg), the μ opioid agonist DAMGO (0.005 and 0.05 μg), tetrodotoxin (5 ng) and neostigmine (0.5 nmol) each reduced the self-administration of nicotine and cocaine maintained on an FR5 schedule of reinforcement. The muscarinic antagonist scopolamine (0.1–1.0 μg) and the opioid antagonist CTOP (1 μg) did not affect self-administration, but reversed the effects of the respective agonist when co-administered with it. Carbachol and DAMGO were also tested in self-administration maintained on a progressive-ratio schedule; each agonist again reduced both nicotine and cocaine self-administration. Conclusions: PPTg manipulations are able to alter established self-administration of nicotine, which acts at the level of the ventral tegmental area and the PPTg itself, and cocaine, which acts through the mesolimbic dopamine system. These data suggest that the PPTg is an important substrate in drug dependence. Electronic Publication     

The role of the avian hippocampus in orientation in space and time

We examined the effects of hippocampus (Hp) and area parahippocampalis (APH) lesions in pigeons on their ability to perform a battery of tasks including autoshaping, time discrimination, spatial memory, and pattern discrimination. Pigeons with Hp-APH lesions were impaired in the acquisition of an autoshaped response, emitting fewer pecks to the stimulus than control animals. Hp-APH pigeons were also impaired in the acquisition of a radial-arm maze analogue task, and those birds that did learn the task seemed to do so by adopting a stereotypic response strategy. In contrast, Hp-APH lesions had no effect on the ability of the birds to discriminate on the basis of either temporal or visual information. Overall, these studies complement our earlier studies and suggest that the avian hippocampus is important for the processing and retention of spatial rather than non-spatial information.