Widespread exposure to Sarcoptes scabiei in wild European rabbits (Oryctolagus cuniculus) in Spain.

Sarcoptic mange was recently described in the wild European rabbit (Oryctolagus cuniculus) in north-eastern Mediterranean Spain, the first such infection reported in this species anywhere in the world. This finding has created concern in conservationists and game managers given that an outbreak of mange after a translocation would have catastrophic consequences for naïve rabbit populations in other parts of Spain. A retrospective serosurvey using an 'in house' ELISA test based on the use of a recombinant antigen aimed at determining the rates of contact with Sarcoptes scabiei was carried out on sera from 966 rabbits collected between 1993 and 2010 in Spain. Antibodies were found in 13% of wild rabbits in 60% of the 53 areas surveyed, as well as in 16 of the 17 Spanish provinces and islands studied. Seropositive rabbits were found amongst the oldest samples analyzed and in all studied years. Antibodies were also detected in 36% of rabbits from the protected island of Dragonera, where rabbits have probably not been released since the 1970s. On Mallorca, where 89 rabbits were inspected for both lesions and antibodies, the prevalence of lesions (5.6%) was much lower than the seroprevalence (22.5%), indicating that rabbits often survive infection or that ELISA detects infected rabbits before they develop visible lesions. Seroprevalence was higher in areas with medium levels of rabbit abundance, no restocking and high rainfall. The results show that mange is widespread in rabbits and that the mite is not a recent introduction. Thus, sarcoptic mange could be considered as an enzootic disease in the wild rabbit and so prophylactic measures implemented during rabbit translocations are to be encouraged to avoid local outbreaks in naïve populations.

Reduced introgression of the Y chromosome between subspecies of the European rabbit (Oryctolagus cuniculus) in the Iberian Peninsula.

The role of the Y chromosome in speciation is unclear. Hybrid zones provide natural arenas for studying speciation, as differential introgression of markers may reveal selection acting against incompatibilities. Two subspecies of the European rabbit (Oryctolagus cuniculus) form a hybrid zone in the Iberian Peninsula. Previous work on mitochondrial DNA (mtDNA), Y- and X-linked loci revealed the existence of two divergent lineages in the rabbit genome and that these lineages are largely subspecies-specific for mtDNA and two X-linked loci. Here we investigated the geographic distribution of the two Y chromosome lineages by genotyping two diagnostic single nucleotide polymorphisms in a sample of 353 male rabbits representing both subspecies, and found that Y chromosome lineages are also largely subspecies-specific. We then sequenced three autosomal loci and discovered considerable variation in levels of differentiation at these loci. Finally, we compared estimates of population differentiation between rabbit subspecies at 26 markers and found a surprising bimodal distribution of F(ST)values. The vast majority of loci showed little or no differentiation between rabbit subspecies while a few loci, including the SRY gene, showed little or no introgression across the hybrid zone. Estimates of population differentiation for the Y chromosome were surprisingly high given that there is male-biased dispersal in rabbits. Taken together, these data indicate that there is a clear dichotomy in the rabbit genome and that some loci remain highly differentiated despite extensive gene flow following secondary contact.

Trypanosoma spp. infection in wild rabbits (Oryctolagus cuniculus) during a restocking program in Southern Spain.

The effect of parasites on managed rabbit populations may prove crucial to develop sanitary strategies during restocking programs of such key prey species. We investigated natural infection of European wild rabbits (Oryctolagus cuniculus) with Trypanosoma spp. in Spain. By fencing part of the warrens during a rabbit restocking program, we induced host variation in rabbit density across these socio-spatial units. We aimed (i) to compare Trypanosoma spp. infection spread between fenced and open warrens and (ii) to assess the relationship between body condition and infection. Trypanosoma spp. parasitaemia peaked in juveniles and decreased onwards. Adult females showed statistically higher infection rates than males. Rabbits from fenced warrens presented statistically higher infection rates than those from open ones, but did not differ in body condition. Parasite abundance negatively correlated with body condition in adults. Sex differences could resemble increased susceptibility to infection in females as a cost of reproduction and/or a higher exposition inside the warrens. Future studies should clarify whether aggregation caused enhanced exposition to intermediate hosts (fleas) and subsequent transmission of the parasite, and we stress that the study of non-lethal parasites during restocking programs provides valuable information on host contact rates and on factors affecting disease susceptibility.

Magnetic resonance spectroscopy for measuring the biodistribution and in situ in vivo pharmacokinetics of fluorinated compounds: validation using an investigation of liver and heart disposition of tecastemizole.

BACKGROUND AND OBJECTIVE: The study of biodistribution and in situ pharmacokinetics is a challenging, but sometimes very important, aspect of premarketing characterization of drugs. We aimed to develop a non-invasive fluorine magnetic resonance (MR) spectroscopic method for the absolute quantitation of a mono-fluorinated compound and of its metabolites in the heart and liver of healthy subjects for this purpose. METHOD: We used fluorine MR spectroscopy (MRS) at 4 T (Tesla) and external standardization in an open label multiple-dose study. Twenty-three healthy adult subjects were enrolled in the study. The surface coil localized fluorine MR spectrum was monitored in the heart and liver at baseline and after oral administration of multiple doses of tecastemizole. Steady-state measurements were made at set time points that depended upon dose, and washout measurements were made only on subjects in which in vivo fluorine signal was observed. RESULTS AND DISCUSSION: At 4 T, under the given experimental conditions, the method had a lower limit of quantitation (LLOQ) of about 2.6 microm and a limit of detection (LOD) of about 0.3 microm for solution state samples (linewidth approximately 15 Hz). The measurement reproducibility was 6.4% using a 50 microm phantom. The effect of MR operator and spectral analyst on the calculated calibration curve slope was small, with inter-rater correlation coefficients of 0.999 and 0.998 respectively. MR signal from fluorine-containing tecastemizole-related moieties was observed in situ only at day 8 in the liver of three of five subjects dosed at 270 mg/day. The average in situ concentration was estimated to be 58+/-22 microm, with an average test-retest reproducibility of 216%. Extrapolating the in vitro results to human measurements, with an approximate linewidth of 250 Hz, predicts in situ LOD and LLOQ values of approximately 6 and 44 microm respectively. However, the human study had a fluorine MRS LOD of approximately 20 microm. The decrease in sensitivity and the increase in variability of the in vivo, in situ measurements compared with the validation study most likely arose from coil placement and incomplete rephasing of the MR signal by the respiratory phase compensation method. CONCLUSION: The measured concentrations were the lowest ever recorded for a multi-dose exogenous mono-fluorinated compound in the human liver using a validated fluorine MR quantitation method. The proposed non-invasive MR method for studying the biodistribution and in situ pharmacokinetics of mono-fluorinated compounds in the liver and heart should have broader application to the development of non-invasive biomarkers.

Effects of vaccination against viral haemorrhagic disease and myxomatosis on long-term mortality rates of European wild rabbits.

The effects of vaccination against myxomatosis and viral haemorrhagic disease (VHD) on long-term mortality rates in European rabbits (Oryctolagus cuniculus) were studied from 1993 to 1996 by radiotracking a free-living population of wild rabbits. During the three months after immunisation, unvaccinated young rabbits weighing between 180 and 600 g were 13.6 times more likely to die than vaccinated young rabbits. In adult rabbits, vaccination did not significantly decrease mortality, mainly owing to the high proportion of rabbits which had previously been exposed to the antigens of both diseases. Compared with adult rabbits with natural antibodies to VHD, rabbits without these antibodies were 5.2 times more likely to die of VHD during annual outbreaks.

Spatial variation in helminth community structure in the red-legged partridge (Alectoris rufa L.): effects of definitive host density.

Parasite community ecology has recently focused on understanding the forces structuring these communities. There are few surveys, however, designed to study the spatial repeatability and predictability of parasite communities at the local scale in one host. The purpose of our study was to address the relationship between infracommunity and component community richness, and to describe spatial variations on the local scale, of helminth parasite communities in an avian host, the red-legged partridge (Alectoris rufta). We sampled 235 wild partridges from 8 separate localities, with different partridge population densities, in the Ciudad Real and Toledo provinces of central Spain, and we determined their overall and intestinal helminth species. We found that habitat variables (mean temperature and land use) were not significantly associated with any component community. The partridge population abundance index was directly correlated with the prevalence and mean intensity of infection but not with component community species richness. There was a curvilinear relationship between infracommunity and component community species richness, as well as negative interspecific associations, for the helminth species assemblage parasitizing the intestine. A nestedness/anti-nestedness pattern, considered as part of a continuum, was associated with prevalence, mean intensity and partridge population abundance index, but not with component community richness. Increases in the partridge population abundance index and the prevalence and mean intensity of infection were associated with increases in helminth community nestedness. Although negative interactions between helminth species could not be ruled out as forces structuring helminth communities, our results suggest that parasite community structure in the red-legged partridge was primarily determined by the extrinsic influence of parasite habitat heterogeneity and its amplification of the differing probabilities of colonization of parasite species.

Descriptive study of an avian pox outbreak in wild red-legged partridges (Alectoris rufa) in Spain.

This study describes the dynamics and epidemiology of an outbreak of avian pox in free-living, red-legged partridges (Alectoris rufa) in southern Spain. Between March 2000 and January 2001, 115 free-living, red-legged partridges (70 juveniles, 45 adults) were captured and radio-tagged. This, together with the necropsy of 44 carcasses (10 juveniles, 34 adults) found in the study area, and the inspection of 108 shot birds (74 juveniles, 34 adults) after a hunting drive in October, permitted a close monitoring of the course of the disease. Forty-one per cent of radio-tagged juveniles but none of 45 radio-tagged adults showed pox-like lesions at the time of capture, recapture, or necropsy. At least 40% of the juveniles that survived into the hunting season, but only 2.9% of the adults inspected at the same time, showed lesions suggestive of infection with avian poxvirus. The survival of juveniles during the peak of the outbreak was much lower than that of the adults, but we found no significant differences between the survival probabilities of juvenile partridges with and without pox-like lesions. Nevertheless, some birds may have developed lesions after their capture. The occurrence and course of the disease in a managed area with intense predator control underlines the need for studies on the combined influence of diseases and predators on population dynamics. Also the need for early detection of diseases for the management of game species is emphasized.

Pathology of avian pox in wild red-legged partridges (Alectoris rufa) in Spain.

The diagnosis and pathology of an avian pox outbreak in free-living red-legged partridges in Cádiz, Southern Spain, is described. Diagnosis of the disease was based on histopathology, ultrastructural examination of, and virus isolation from lesions of necropsied animals. Lesions were present mainly in juvenile partridges (41%), and were observed primarily on the dorsal part of the digits or on the hock joint. The lesions ranged from small wartlike nodules to large tumor-like lesions. The presence of acute lesions of any grade as opposed to absence of lesions or healed lesions adversely affected body condition of the partridges (P <.01). Further investigations on the epidemiology of the disease and on the relation of the isolated strains to other avian poxviruses are under way.

Epidemiology of viral haemorrhagic disease and myxomatosis in a free-living population of wild rabbits.

From January 1993 to June 1996, the epidemiology of myxomatosis and viral haemorrhagic disease (VHD) was studied in a free-living population of wild rabbits (Oryctolagus cuniculus) in Spain by means of serological surveys and radiotracking. Myxomatosis was endemic and associated with the breeding period. Its serological pattern was characterised by a 100 per cent prevalence of antibodies in adult rabbits and a rapid increase in antibodies in young rabbits in their first year. No mortality from myxomatosis was detected in adults, and mortality in young rabbits could not be estimated because of interference by predators and scavengers and the deaths of many radiotagged rabbits inside their burrows. VHD was also an endemic disease associated with the breeding period. Adults had a higher prevalence of antibodies against VHD than young rabbits, reaching values of 80 to 90 per cent. During the study, there was an increase in rabbit numbers as a result of a decrease in mortality from predation which was associated with an increase in mortality due to VHD and in the prevalence of antibodies to VHD. Mortality from VHD was lower in rabbits with VHD antibodies than in seronegative rabbits, but some mortality from the disease was also detected in seropositive rabbits. The annual mean mortality rate due to VHD in adult rabbits was estimated to be 21.8 per cent.

Chronic citicoline increases phosphodiesters in the brains of healthy older subjects: an in vivo phosphorus magnetic resonance spectroscopy study.

RATIONALE: Phosphatidylcholine (PtdCho) in brain cell membranes decreases with age. Evidence from both animal and in vitro studies indicates that CDP-choline (citicoline) administration may increase phosphatidylcholine (PtdCho) synthesis and might reverse PtdCho loss. OBJECTIVES: We investigated whether oral citicoline can increase PtdCho synthesis in the brains of older subjects by measuring levels of phosphorus-containing metabolites using proton-decoupled phosphorus magnetic resonance spectroscopy ((31)P-MRS) before and after citicoline treatment. METHODS: All subjects took 500 mg citicoline once orally each day for 6 weeks, then took either citicoline or placebo once orally per day for a second 6-week period. Subjects underwent a (31)P-MRS scan at baseline and following 6 and 12 weeks of treatment. RESULTS: Treatment with citicoline for 6 weeks was associated with a 7.3% increase from baseline levels in brain phosphodiesters ( P=0.008), including an 11.6% increase in glycerophosphoethanolamine ( P=0.002) and a 5.1% increase in glycerophosphocholine ( P=0.137). Subjects who continued to take citicoline for the second 6-week period did not show significant additional increases in the levels of these metabolites. No changes were seen in other phosphorus-containing metabolites. There was a correlation between improvement on the California Verbal Learning Test and increase in phosphodiesters. CONCLUSIONS: The increases in phosphodiesters seen in this study indicate that phospholipid synthesis and turnover were stimulated by 6 weeks of oral citicoline. These results in humans support previous in vitro and animal studies and suggest that the administration of oral citicoline may be of use in reversing age-related changes in the brain.

Marked differences in the splanchnometry of farm-bred and wild red-legged partridges (Alectoris rufa L.).

Relative weights of heart, spleen, pancreas, and liver and the relative lengths of the small intestine and the cecum were taken from 40 farm-bred and 43 wild juvenile red-legged partridges (Alectoris rufa Linnaeus) in central Spain. Expressed as a ratio to head and body length, farm-bred partridges had lighter hearts (17% lighter), spleens (78%), and livers (29%) and shorter small intestines (15%) and cecae (20%), than wild birds of the same age. When expressed as a ratio to body weight, farm-bred juvenile red-legged partridges had lighter hearts (12%) and livers (23%) and shorter small intestines (9%) and cecae (12%) than wild partridges. Those differences might have been produced by diet differences (such as fiber-poor, high-energy feeds used on farms) and may affect the survival of farm-bred partridges after release.

Cocaine-induced cerebral vasoconstriction differs as a function of sex and menstrual cycle phase.

BACKGROUND: Chronic cocaine abusing women experience fewer cerebral perfusion defects and less neuronal injury than men with comparable drug use histories. This study assessed whether a basis for this discrepancy is a sex difference in cocaine's acute cerebrovascular effects. METHODS: The subjects in this study were 13 healthy and neurologically normal women, reporting occasional cocaine (mean 13, range 1-40 lifetime cocaine exposures). All subjects were administered cocaine (0.4 mg/kg) intravenously, during both the follicular (days 3-8) and luteal (days 18-24) menstrual cycle phases. Dynamic susceptibility contrast magnetic resonance imaging assessments of relative global cerebral blood volume (CBV) changes were conducted on both study days, 10 min after cocaine administration. RESULTS: Cocaine did not alter CBV in follicular phase women, but reduced luteal phase CBV by 10%, indicative of vasoconstriction (analysis of variance [ANOVA], F = 5.1, p <.05). Postcocaine CBV was lower in men administered the drug via an identical protocol relative to follicular phase women (ANOVA, F = 5.4, p <.04). Postcocaine CBV was also lower in the male referent group relative to luteal phase women, but this difference did not achieve statistical significance. No measurable sex or menstrual cycle phase differences in cocaine's cardiovascular effects were noted. CONCLUSIONS: These findings suggest both menstrual cycle phase and sex differences in cocaine's acute cerebrovascular effects, which may contribute to sex differences in the severity of brain dysfunction found in chronic cocaine abusers. These findings imply that gonadal steroids or the factors they modulate merit study as possible therapeutic agents for reducing cocaine-induced cerebrovascular disorders.

Presynaptic signalling mediated by mono- and dinucleotides in the central nervous system.

Synaptosomal preparations from rat midbrain exhibit specific responses to both ATP and Ap(5)A, which elicit a Ca(2+) entrance to the presynaptic terminals. Studies of isolated single terminals showed that not all the terminals contain ionotropic receptors for nucleotides, in fact only 46% of them do. Of these, 12% responded only to the dinucleotide Ap(5)A, and 20% to the mononucleotide ATP. At the presynaptic level, diinosine pentaphosphate, Ip(5)I, is a good tool to specifically block dinucleotide responses, which are inhibited at low nM concentration, versus the high microM concentrations required to block ATP responses. There is evidence for a presynaptic control of mononucleotide and dinucleotide responses, mediated by metabotropic and ionotropic receptors. Stimulation of adenosine A1 receptors increases the affinity of dinucleotide receptors by five orders of magnitude, from 30 microM to 680 pM for control and in the presence of A1 agonist, respectively.

Illicit cocaine use patterns in intravenous-naive cocaine users following investigational intravenous cocaine administration.

This study evaluated whether cocaine use patterns changed following investigational intravenous cocaine administration to intravenous-naive cocaine users. Subjects were respondents to a follow-up survey who had participated in one to three intravenous double-blind cocaine (0.2 or 0.4 mg/kg) administration studies. The group included healthy men (n = 17) and women (n = 8) with histories of occasional cocaine use (lifetime self-reported use of 12+/-12 (mean +/- S.D.) exposures, primarily via nasal insufflation) who were recontacted an average of 39 weeks (range 7-107 weeks) after study participation. The recontacted group constituted 45% of the total eligible sample of 55 subjects. Baseline demographics for the recontacted and non-recontacted (n = 30) samples were similar, suggesting that the recontacted sample was representative of the group as a whole. Investigational cocaine exposure did not induce adverse health events in any subject. Self-reported cocaine use estimates obtained at follow-up were compared to baseline estimates obtained with identical questionnaires and were highly concordant (Spearman rank correlation p = 0.52 and 0.78, respectively; P < 0.02 and < 0.0002, respectively). This suggests that participants provided stable and reliable reports of cocaine use. No subject reported either illicit intravenous cocaine use or altered frequency of illicit cocaine use by the customary route after investigational intravenous cocaine exposure. These data suggest that illicit cocaine use frequencies and routes of administration are not altered following investigational intravenous cocaine administration to healthy, occasional cocaine users.

Choline, myo-inositol and mood in bipolar disorder: a proton magnetic resonance spectroscopic imaging study of the anterior cingulate cortex.

OBJECTIVES: Alterations in choline and myo-inositol metabolism have been noted in bipolar disorder, and the therapeutic efficacy of lithium in mania may be related to these effects. We wished to determine the relationship between anterior cingulate cortex choline and myo-inositol levels, assessed using proton magnetic resonance spectroscopic imaging (MRSI), and mood state in subjects with bipolar disorder. METHODS: Serial assessments of anterior cingulate cortex choline and myo-inositol metabolism were performed in nine subjects with bipolar disorder, taking either lithium or valproate, and 14 controls. Each bipolar subject was examined between one and four times (3.1 +/- 1.3). On the occasion of each examination, standardized ratings of both depression and mania were recorded. RESULTS: In the left cingulate cortex, the bipolar subjects' depression ratings correlated positively with MRSI measures of Cho/Cr-PCr. In the right cingulate cortex, the Cho/Cr-PCr ratio was significantly higher in subjects with bipolar disorder compared with control subjects. In addition, bipolar subjects not taking antidepressants had a significantly higher right cingulate cortex Cho/Cr-PCr ratio compared with patients taking antidepressants or controls. No clinical or drug-related changes were observed for the Ino/Cr-PCr ratio. CONCLUSIONS: The results of this study suggest that bipolar disorder is associated with alterations in the metabolism of cytosolic, choline-containing compounds in the anterior cingulate cortex. As this resonance arises primarily from phosphocholine and glycerophosphocholine, both of which are metabolites of phosphatidylcholine, these results are consistent with impaired intraneuronal signaling mechanisms.

Cerebral phosphorus metabolite abnormalities in opiate-dependent polydrug abusers in methadone maintenance.

This study evaluated cerebral phosphorus metabolites in opiate-dependent polydrug abusers in methadone maintenance therapy (MMT) and determined whether metabolite profiles differed based on treatment duration. Phosphorus magnetic resonance spectroscopy (31P-MRS) data were acquired with the ISIS volume localization method from a 50-mm thick axial brain slice through the orbitofrontal and occipital cortices. Study subjects included 15 MMT subjects, seven having undergone treatment for an average of 39 +/- 23 weeks (mean +/- S.D.) and eight having undergone treatment for 137 +/- 53 weeks, as well as an age matched comparison group (n = 16). The methadone dose administered on the study day averaged 70.5 +/- 17.1 mg and was statistically equivalent in short- and long-term subgroups. MMT subjects (n = 15) differed from control subjects in percent phosphocreatine (%PCr) levels (-13%), and in both phosphomonoester (%PME, +13%) and phosphodiester (%PDE, +10%) levels, which likely reflect abnormalities in energy and phospholipid metabolism, respectively. There were no sex effects or group by sex interaction effects on these measures. In short-term MMT treatment subjects, abnormal %PCr (-18%), %PME (+20%) and %PDE (+17%) levels were found compared with control subjects. The only metabolite abnormality detected in long-term MMT subjects was decreased %PCr (-9%), in spite of continued illicit drug abuse. From these data, we conclude that polydrug abusers in MMT have 31P-MRS results consistent with abnormal brain metabolism and phospholipid balance. The nearly normal metabolite profile in long-term MMT subjects suggests that prolonged MMT may be associated with improved neurochemistry.

Habitat related differences in helminth parasites of red foxes in the Ebro valley.

The prevalences of helminth parasites found on red foxes collected in two different habitats of the Ebro Valley, in north-eastern Spain were compared. Twenty helminth species, including one trematode, six cestodes, 12 nematodes and one acanthocephalan were found. Metorchis albidus, Uncinaria stenocephala and Dirofilaria immitis were more prevalent in the irrigated lands close to the main rivers of the study area, whereas Trichuris vulpis and Pterygodermatites affinis showed higher prevalences in the semiarid stepparian habitat. Habitat characteristics need to be considered when surveying helminths over large geographical areas. The study shows that in the Ebro Valley the fox constitutes a reservoir host for several helminth species that are parasites of the domestic dog or the wolf, or may have importance as zoonoses.

First epizootic of rabbit hemorrhagic disease in free living populations of Oryctolagus cuniculus at Doñana National Park, Spain.

The first known epizootic of rabbit hemorrhagic disease (RHD) occurred in two free-living wild rabbit (Oryctolagus cuniculus) populations at Doñana National Park, Spain. Rabbit population density was not correlated to RHD mortality. Only adult animals were affected; males and females had similar mortality rates.