Marbofloxacin disposition after intravenous administration of a single dose in wild mallard ducks (Anas platyrhynchos).

Marbofloxacin, a fluoroquinolone developed specifically for veterinary use, has demonstrated considerable pharmokinetic variation among avian species. The goal of this study was to determine the disposition kinetics of marbofloxacin in mallard ducks (Anas platyrhynchos) after a single intravenous injection. Six wild mallard ducks were used in the study. Marbofloxacin was injected at a dose of 2 mg/kg into the basilic vein, and blood was subsequently collected at regular intervals from each bird. Plasma marbofloxacin concentrations were determined by using high-performance liquid chromatography. The volume of distribution at steady state was 1.78 +/- 0.37 L/kg, and the total plasma clearance was 0.59 +/- 0.08 L/kg per hour. Marbofloxacin had a relatively short permanence, with a elimination half-life of 2.81 +/- 1.20 hours, a terminal half-life of 2.43 +/- 0.61 hours, and a mean residence time of 2.99 +/- 0.52 hour. The maximum observed concentration (Cmax) and area under the curve (AUC) were 1.34 +/- 0.27 microg/mL and 3.75 +/- 0.56 microg x h/mL, respectively. Values of minimum inhibitory concentration (MIC), Cmax, and AUC have been used to predict the clinical efficacy of a drug in treating bacterial infections, with a Cmax: MIC value of 10 and an AUC: MIC ratio of 125-250 associated with optimal bactericidal effects. By using the study data and MIC breakpoints of 0.125 microg/mL or 0.2 microg/mL, values derived for Cmax: MIC were 9.37 +/- 0.99 and 5.85 +/- 0.62, respectively, and for AUC: MIC were 29.99 +/- 4.51 and 18.74 +/- 2.82, respectively. By using MIC values of 0.125 and 0.2 microg/mL and a target AUC: MIC = 125, the calculated optimal daily marbofloxacin dosages for mallard ducks were 9.24 and 14.78 mg/kg, respectively. These results suggest that, primarily because of the high total plasma clearance observed, the marbofloxacin dose for treatment of bacterial diseases in mallard ducks should be increased after intravenous administration. Intravenous doses of 10-15 mg/kg should be assessed by studying their potential toxicity and efficacy in sick birds.

Possible cantharidin poisoning of a great bustard (Otis tarda).

A possible cantharidin intoxication of a great bustard (Otis tarda) was described. This wild bird died by a traumatism, but also presented diarrhoea, congestion of the gastrointestinal tract and kidneys and had ingested several blister beetles of the species Berberomeloe majalis. The analysis of the stomach content by GC-MS revealed the presence of cantharidin at a concentration of 1.37 µg/g of wet weight, a similar level than in other birds poisoned in captivity.

When conservation management becomes contraindicated: impact of food supplementation on health of endangered wildlife.

Understanding the conditions that force the implementation of management actions and their efficiency is crucial for conservation of endangered species. Wildlife managers are widely and increasingly using food supplementation for such species because the potentially immediate benefits may translate into rapid conservation improvements. Supplementary feeding can also pose risks eventually promoting undesired, unexpected, subtle, or indirect, and often unnoticed, effects that are generally poorly understood. For two decades, intensive food supplementation has been used in attempting to improve the breeding productivity of the Spanish Imperial Eagle, Aquila adalberti, one of the most endangered birds of prey in the world. Here, we examined the impact of this intensive management action on nestling health, including contamination, immunodepression, and acquisition of disease agents derived from supplementation techniques and provisioned food. Contrary to management expectations, we found that fed individuals were often inadvertently "medicated" with pharmaceuticals (antibiotics and antiparasitics) contained in supplementary food (domestic rabbits). Individuals fed with medicated rabbits showed a depressed immune system and a high prevalence and richness of pathogens compared with those with no or safe supplementary feeding using non-medicated wild rabbits. A higher presence of antibiotics (fluoroquinolones) was found in sick as opposed to healthy individuals among eaglets with supplementary feeding, which points directly toward a causal effect of these drugs in disease and other health impairments. This study represents a telling example of well-meaning management strategies not based on sound scientific evidence becoming a "contraindicated" action with detrimental repercussions undermining possible beneficial effects by increasing the impact of stochastic factors on extinction risk of endangered wildlife.

Disposition of marbofloxacin in vulture (Gyps fulvus) after intravenous administration of a single dose.

The pharmacokinetics properties of marbofloxacin were studied in adult Eurassian Griffon vulture after single-dose intravenous (IV) administration of 2mg/kg. Drug concentration in plasma was determined by high-performance liquid chromatography and the data obtained were subjected to compartmental and non-compartmental kinetic analysis. Marbofloxacin presented a volume of distribution at steady-state (Vdss) of 1.51±0.22L and total plasma clearance (Cl) of 0.109±0.023L/hkg. The permanence of this drug was long in vultures (T(1/2)(λ)=12.51±2.52h; MRT(∞)=13.54±2.29h). The optimal dose of marbofloxacin estimated is 2.73mg/kg per day for the treatment of infections in vultures with MIC(90)=0.2µg/mL.

MHC diversity and differential exposure to pathogens in kestrels (Aves: Falconidae).

Pathogen diversity is thought to drive major histocompatibility complex (MHC) polymorphism given that host's immune repertories are dependent on antigen recognition capabilities. Here, we surveyed an extensive community of pathogens (n = 35 taxa) and MHC diversity in mainland versus island subspecies of the Eurasian kestrel Falco tinnunculus and in a sympatric mainland population of the phylogenetically related lesser kestrel Falco naumanni. Insular subspecies are commonly exposed to impoverished pathogen communities whilst different species' ecologies and contrasting life-history traits may lead to different levels of pathogen exposure. Although specific host traits may explain differential particular infections, overall pathogen diversity, richness and prevalence were higher in the truly cosmopolitan, euriphagous and long-distance disperser Eurasian kestrel than in the estenophagous, steppe-specialist, philopatric but long-distance migratory lesser kestrel. Accordingly, the continental population of Eurasian kestrels displayed a higher number (64 vs. 49) as well as more divergent alleles at both MHC class I and class II loci. Detailed analyses of amino acid diversity revealed that significant differences between both species were exclusive to those functionally important codons comprising the antigen binding sites. The lowest pathogen burdens and the smallest but still quite divergent set of MHC alleles (n = 16) were found in island Eurasian kestrels, where the rates of allele fixation at MHC loci seem to have occurred faster than at neutral markers. The results presented in this study would therefore support the role of pathogen diversity and abundance in shaping patterns of genetic variation at evolutionary relevant MHC genes.

Detection of Feline leukemia virus in the endangered Iberian lynx (Lynx pardinus).

Feline retroviruses are rarely reported in lynx species. Twenty-one Iberian lynx (Lynx pardinus) blood and tissue samples collected from Doñana National Park and Los Villares (Sierra Morena) in southern Spain during 1993-2003 were analyzed by polymerase chain reaction to amplify nucleic acids from feline retroviruses. Six samples were positive for Feline leukemia virus (FeLV), but no samples tested positive for Feline immunodeficiency virus. The BLAST analysis indicated that 5 of the 6 sequences were closely related to FeLV strain Rickard subgroup A, whereas 1 sequence was identical to FeLV. To the authors' knowledge, this is the first report of FeLV in the endangered Iberian lynx.

Antibiotics threaten wildlife: circulating quinolone residues and disease in Avian scavengers.

Antibiotic residues that may be present in carcasses of medicated livestock could pass to and greatly reduce scavenger wildlife populations. We surveyed residues of the quinolones enrofloxacin and its metabolite ciprofloxacin and other antibiotics (amoxicillin and oxytetracycline) in nestling griffon Gyps fulvus, cinereous Aegypius monachus and Egyptian Neophron percnopterus vultures in central Spain. We found high concentrations of antibiotics in the plasma of many nestling cinereous (57%) and Egyptian (40%) vultures. Enrofloxacin and ciprofloxacin were also found in liver samples of all dead cinereous vultures. This is the first report of antibiotic residues in wildlife. We also provide evidence of a direct association between antibiotic residues, primarily quinolones, and severe disease due to bacterial and fungal pathogens. Our results indicate that, by damaging the liver and kidney and through the acquisition and proliferation of pathogens associated with the depletion of lymphoid organs, continuous exposure to antibiotics could increase mortality rates, at least in cinereous vultures. If antibiotics ingested with livestock carrion are clearly implicated in the decline of the vultures in central Spain then it should be considered a primary concern for conservation of their populations.

The pharmacokinetic behaviour of marbofloxacin in Eurasian buzzards (Buteo buteo) after intraosseous administration.

This study reports on the administration of a single dose of marbofloxacin (2 mg/kg) to five adult Eurasian buzzards (Buteo buteo) by the intraosseous (IO) route, which has been proposed as a rapid and efficient means for the parenteral delivery of antimicrobial drugs. The drug was rapidly absorbed. Peak marbofloxacin concentration (C(max)) in plasma and area under the concentration-time curve (AUC) of 1.92+/-0.78 microg/mL and 8.53+/-2.73 microg h/mL, respectively. The time marbofloxacin remained in the plasma after IO administration was relatively short (elimination half-life, t(1/2beta)=4.91+/-0.65 h; mean residence time (MRT)=5.38+/-0.57 h). Single dose marbofloxacin gave values for C(max)/minimum inhibitory concentration (MIC) of 19.2 and an AUC/MIC value of 85.3h after IO administration. The IO route appears to be practical and effective for the rapid delivery of marbofloxacin to buzzards.

First report of an intraerythrocytic small piroplasm in wild Iberian lynx (Lynx pardinus).

A wild injured Iberian lynx (Lynx pardinus) was taken from the Sierra Morena population. During the health check small intraerythrocytic piroplasms, morphologically indistinguishable from other feline piroplasms, were observed in Wright-Giemsa-stained blood films. Amplification by polymerase chain reaction of a portion of the 18S nuclear small subunit (NSS) rRNA gene and sequencing revealed similarity of the unknown organism with sequences obtained from Pallas's cat from Mongolia and from a domestic cat in Spain. In a retrospective (1993-2003) study of 50 Iberian lynx tissue samples, no amplifications of the 18S NSS rRNA gene of the organism were obtained. This is the first report of a naturally occurring erythroparasitemia in the Iberian lynx and the first documented case of naturally occurring piroplasm infection in a free-ranging felid from Europe.

Blood chemistry, protein electrophoresis, and hematologic values of captive Spanish imperial eagles (Aquila adalberti).

Hemograms and plasma chemistry values are presented for six male and six female, adult, clinically normal, captive Spanish imperial eagles (Aquila adalberti). No value was substantially different from that which might be predicted on the basis of work in other related species. This data should prove useful for the interpretation of laboratory findings in future clinical cases of this endangered species of eagle.