Blood-gas and electrolyte values for Amazon parrots (Amazona aestiva)

The aim was to provide reference data for blood gas/acid-base status and electrolytes for non-anesthetized Amazon parrots (Amazona aestiva). Thirty-five adult parrots from Tietê ecologic park were utilized. Arterial blood (0.3ml) samples were anaerobically collected from the superficial ulnar artery in heparinized (sodium heparin) 1-ml plastic syringes. The samples were immediately analyzed through a portable analyzer (i-STAT*, Abbot, Illinois, USA) with cartridges (EG7+). These data were grouped in such a way as to present both mean and standard deviation: body weight (360±37g), respiratory rate (82±33 b/m), temperature (41.8±0.6°C), hydrogen potential (7.452±0.048), carbon dioxide partial pressure (22.1±4.0mmHg), oxygen partial pressure (98.1±7.6mmHg), base excess (-7.9±3.1), plasma concentration of bicarbonate ions (14.8±2.8mmol/L), oxygen saturation (96.2±1.1%), plasma concentration of sodium (147.4±2.2mmol/L), plasma concentration of potassium (3.5±0.53mmol/L), plasma concentration of calcium (0.8±0.28mmol/L), hematocrit (38.7±6.2%) and concentration of hemoglobin (13.2±2.1g/dl). This study led us to conclude that, although the results obtained showed hypocapnia and low values of bicarbonate and base excess, when compared to other avian species, these data are very similar. Besides, in spite of the equipment being approved only for human beings, it was considered simple and very useful in the analysis of avian blood samples. By using this equipment we were able to provide references data for non-anaesthetized Amazon parrots.

Amitose de eritroblastos e eritrocitos no sangue circulante de aves

The author reports the finding of direct division of erythroblasts and erythrocytes in avian blood.

Haematophagy and cleptohaematophagy of Clerada apicicornis (Hemiptera: Lygaeidae), a potential biological control agent of Rhodnius prolixus (Hemiptera: Reduviidae)

Because of its ability to prey on Triatominae in rural houses, Clerada apicicornis has been suggested as a potential biological control agent of Rhodnius prolixus. It has also been suggested as a potential vector of mammalian trypanosomes such as Trypanosoma cruzi, because of its ability to take blood directly from mammals. To help resolve these conflicting ideas, we assessed the haematophagic behaviour of C. apicicornis by carrying out feeding trials on laboratory animals. Cleptohaematophagic behaviour was also assessed by allowing C. apicicornis to feed on R. prolixus previously engorged with avian blood. The low proportion of blood meals taken directly from laboratory animals indicates a facultative haematophagy in this species, whereas a greater proportion of nymphs and adults were able to obtain vertebrate blood by predation on engorged R. prolixus. The results suggest that C. apicicornis is unlikely to be effective as a biological control agent, but is also unlikely to have a significant role in the transmission of vertebrate pathogens.

Altitudinal variation in haemosporidian parasite distribution in great tit populations.

BACKGROUND: One of the major issues concerning disease ecology and conservation is knowledge of the factors that influence the distribution of parasites and consequently disease outbreaks. This study aimed to investigate avian haemosporidian composition and the distribution of these parasites in three altitudinally separated great tit (Parus major) populations in western Switzerland over a three-year period. The objectives were to determine the lineage diversity of parasites occuring across the study populations and to investigate whether altitudinal gradients govern the distribution of haemosporidian parasites by lineage. METHODS: In this study molecular approaches (PCR and sequencing) were used to detect avian blood parasites (Plasmodium sp., Haemoproteus sp. and Leucocytozoon sp.) in populations of adult great tits caught on their nests during three consecutive breeding seasons. RESULTS: High levels of parasite prevalence (88-96%) were found across all of the study populations with no significant altitude effect. Altitude did, however, govern the distribution of parasites belonging to different genera, with Plasmodium parasites being more prevalent at lower altitudes, Leucocytozoon parasites more at high altitude and Haemoproteus parasite prevalence increasing with altitude. A total of 27 haemosporidian parasite lineages were recorded across all study sites, with diversity showing a positive correlation to altitude. Parasites belonging to lineage SGS1 (P. relictum) and PARUS4 and PARUS19 (Leucocytozoon sp.) dominated lower altitudes. SW2 (P. polare) was the second most prevalent lineage of parasite detected overall and these parasites were responsible for 68% of infections at intermediate altitude, but were only documented at this one study site. CONCLUSIONS: Avian haemosporidian parasites are not homogeneously distributed across host populations, but differ by altitude. This difference is most probably brought about by environmental factors influencing vector prevalence and distribution. The high occurrence of co-infection by different genera of parasites might have pronounced effects on host fitness and should consequently be investigated more rigorously.

Migratory and Carnivorous Birds in Brazil: Reservoirs for Anaplasma and Ehrlichia Species?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Patologia clínica em aves de produção - Uma ferramenta para monitorar a sanidade avícola - Revisäo

Clinical pathology has been used in veterinary medicine for many years to evaluate metabolic changes that may indicate any sign of disease in animals. Even though the use of blood parameters is routine in companion animals, it is not commonly used for avian clinical evaluation either wild or production birds. Among others, the lack of information of avian blood reference values has limited the use of this tool in avian medicine. The blood parameters in avian medicine are helpful to evaluate aspects related to animal health for wild and also production birds. Thus, this review paper presents some ways to use clinical pathology parameters to evaluate and to monitor the avian health.

The haematological profile of female bronze turkeys (Meleagris gallopavo) vaccinated with various commercial strains of Newcastle disease

The effects of vaccination on avian blood parameters are poorly understood. The present study was designed to evaluate whether different strains (Ulster 2C, B1, live LaSota and inactivated LaSota) of Newcastle disease vaccines had an effect on the haematological profile of female turkeys. Seventy-five female turkeys were allocated to treatment groups according to vaccination strain. All the birds, except those in the control group, were vaccinated at 32 weeks of age and revaccinated at 40 and 48 weeks of age. Blood samples were obtained for haematological analyses and serum samples for the haemagglutination inhibition test. Haemoglobin concentration was significantly lower (p < 0.05) in vaccinated female turkeys than in the control birds 28 days after vaccination. Monocytes were significantly higher (p < 0.05) in 44-week-old female turkeys vaccinated with inactivated LaSota strain compared with the other groups. Turkeys vaccinated with the B1 strain showed significantly higher (p < 0.05) total white blood cell counts compared with the other groups vaccinated with various commercial strains of the Newcastle disease virus. In conclusion, female turkeys showed significant differences in haemoglobin concentrations, monocytes and white blood cell counts when vaccinated against Newcastle disease.

Structural, cytochemical, immunocytochemical and ultrastructural characterization of blood granulocytes of the roadside hawk Buteo magnirostris (Gmelin, 1788) (Avian, Falconiform)

In the peripheral blood of the roadside hawk, Buteo magnirostris, the following types of granulocytic leucocytes were identified: heterophil, eosinophil and basophil. The heterophils presented acidophilic and spindle shaped granules, the eosinophils possess spherical eosinophilic granules and the basophils showed spherical and basophilic granules. The heterophils and eosinophils presented positive cytochemical reaction to glycogen and basic polyaminoacid, while the eosinophils presented sudanophilic granules, which were also positive for myeloperoxidase. The heterophils, alone, presented positivity for acid phosphatase in some granules and immunoreactivity to TGF-β1 was observed only in the cytoplasm of the eosinophils. Electron microscopy demonstrated the heterophil granules as predominantly spindle shaped, being strongly electron-dense, while the eosinophils had numerous uniformly electron-dense spherical granules and the basophils presented three different types of granules identified according to their electron-density and the aspect of their matrix.

The pulmonary blood-gas barrier in the avian embryo: inauguration, development and refinement

In vertebrates, efficient gas exchange depends primarily on establishment of a thin blood-gas barrier (BGB). The primordial air conduits of the developing avian lung are lined with a cuboidal epithelium that is ultimately converted to a squamous one that participates in the formation of the BGB. In the early stages, cells form intraluminal protrusions (aposomes) then transcellular double membranes separating the aposome from the basal part of the cell establish, unzip and sever the aposome from the cell. Additionally, better endowed cells squeeze out adjacent cells or such cells constrict spontaneously thus extruding the squeezed out aposome. Formation of vesicles or vacuoles below the aposome and fusion of such cavities with their neighboring cognates results in severing of the aposome. Augmentation of cavities and their subsequent fusion with the apical plasma membranes results in formation of numerous microfolds separating concavities on the apical part of the cell. Abscission of such microfolds results in a smooth squamous epithelium just before hatching.

Prevalence of avian haematozoa in São Paulo state, Brazil

The blood parasites of 15,574 birds representing 266 species of 43 families from primarily three areas in São Paulo State, Brazil were examined for haematozoa. Only 1240 (8.0% of 121 species fo 32 families were infected with blood parasites. This prevalence was similar to that reported in a previous study. Species of Haemoproteus were the most commonly encountered haematozoans (38.9%), followed by microfilaria (30.7%), Trypanosoma (13.7%), Plasmodium (7.5%) and Leucocytozoon (0.8%). Prevalence of parasitism was significantly different between the three major areas sampled. It was shown that this was due in part to differences in the avifaunas at both the familial and species levels. Prevalence varied markedly in only one of the 10 years of the study. Monthly fluctuations in prevalence were largely due to changes in relative proportions of highlytion of both. Prevalences of both microfilaria and Trypanosoma were higher than reported for any other similar survey in the world.

Re-description of Trypanosoma corvi Stephens and Christophers,1908 Emend. Baker, 1976 and remarks on the Trypanosomes of the Avian Family Corvidae

The trypomastigote, epimastigote and amastigote stages of Trypanosoma corvi Stephens and Christophers, 1908 emend. Baker, 1976 from the peripheral blood, heart and bone marrow are described herein. Other trypanosomes described from the Corvidae are compared to T. corvi and their status is discussed.

Avian erythrocytes have functional mitochondria, opening novel perspectives for birds as animal models in the study of ageing.

BACKGROUND: In contrast to mammalian erythrocytes, which have lost their nucleus and mitochondria during maturation, the erythrocytes of almost all other vertebrate species are nucleated throughout their lifespan. Little research has been done however to test for the presence and functionality of mitochondria in these cells, especially for birds. Here, we investigated those two points in erythrocytes of one common avian model: the zebra finch (Taeniopygia guttata). RESULTS: Transmission electron microscopy showed the presence of mitochondria in erythrocytes of this small passerine bird, especially after removal of haemoglobin interferences. High-resolution respirometry revealed increased or decreased rates of oxygen consumption by erythrocytes in response to the addition of respiratory chain substrates or inhibitors, respectively. Fluorometric assays confirmed the production of mitochondrial superoxide by avian erythrocytes. Interestingly, measurements of plasmatic oxidative markers indicated lower oxidative stress in blood of the zebra finch compared to a size-matched mammalian model, the mouse. CONCLUSIONS: Altogether, those findings demonstrate that avian erythrocytes possess functional mitochondria in terms of respiratory activities and reactive oxygen species (ROS) production. Interestingly, since blood oxidative stress was lower for our avian model compared to a size-matched mammalian, our results also challenge the idea that mitochondrial ROS production could have been one actor leading to this loss during the course of evolution. Opportunities to assess mitochondrial functioning in avian erythrocytes open new perspectives in the use of birds as models for longitudinal studies of ageing via lifelong blood sampling of the same subjects.

Oseltamivir in seasonal, avian H5N1 and pandemic 2009 A/H1N1 influenza: pharmacokinetic and pharmacodynamic characteristics.

Oseltamivir is the ester-type prodrug of the neuraminidase inhibitor oseltamivir carboxylate. It has been shown to be an effective treatment for both seasonal influenza and the recent pandemic 2009 A/H1N1 influenza, reducing both the duration and severity of the illness. It is also effective when used preventively. This review aims to describe the current knowledge of the pharmacokinetic and pharmacodynamic characteristics of this agent, and to address the issue of possible therapeutic drug monitoring. According to the currently available literature, the pharmacokinetics of oseltamivir carboxylate after oral administration of oseltamivir are characterized by mean ± SD bioavailability of 79 ± 12%, apparent clearance of 25.3 ± 7.0 L/h, an elimination half-life of 7.4 ± 2.5 hours and an apparent terminal volume of distribution of 267 ± 122 L. A maximum plasma concentration of 342 ± 83 μg/L, a time to reach the maximum plasma concentration of 4.2 ± 1.1 hours, a trough plasma concentration of 168 ± 32 μg/L and an area under the plasma concentration-time curve from 0 to 24 hours of 6110 ± 1330 μg · h/L for a 75 mg twice-daily regimen were derived from literature data. The apparent clearance is highly correlated with renal function, hence the dosage needs to be adjusted in proportion to the glomerular filtration rate. Interpatient variability is moderate (28% in apparent clearance and 46% in the apparent central volume of distribution); there is no indication of significant erratic or limited absorption in given patient subgroups. The in vitro pharmacodynamics of oseltamivir carboxylate reveal wide variation in the concentration producing 50% inhibition of influenza A and B strains (range 0.17-44 μg/L). A formal correlation between systemic exposure to oseltamivir carboxylate and clinical antiviral activity or tolerance in influenza patients has not yet been demonstrated; thus no formal therapeutic or toxic range can be proposed. The pharmacokinetic parameters of oseltamivir carboxylate after oseltamivir administration (bioavailability, apparent clearance and the volume of distribution) are fairly predictable in healthy subjects, with little interpatient variability outside the effect of renal function in all patients and bodyweight in children. Thus oseltamivir carboxylate exposure can probably be controlled with sufficient accuracy by thorough dosage adjustment according to patient characteristics. However, there is a lack of clinical study data on naturally infected patients. In addition, the therapeutic margin of oseltamivir carboxylate is poorly defined. The usefulness of systematic therapeutic drug monitoring in patients therefore appears to be questionable; however, studies are still needed to extend the knowledge to particular subgroups of patients or dosage regimens.

Analysis of hematologic and serum chemistry values of Spheniscus magellanicus with molecular detection of avian malarial parasites (Plasmodium spp.)

Magellanic penguins (Spheniscus magellanicus) routinely migrate from their breeding colonies to Southern Brazil often contracting diseases during this migration, notably avian malaria, which has been already reported in Brazil and throughout the world. Detection of Plasmodium spp. in blood smears is the routine diagnostic method of avian malaria, however it has a low sensitivity rate when compared to molecular methods. Considering the negative impact of avian malaria on penguins, the aim of this study was to detect the presence of Plasmodium spp. in Magellanic penguins using Polymerase Chain Reaction (PCR) and by verifying clinical, hematological, and biochemical alterations in blood samples as well as to verify the likely prognosis in response to infection. Blood samples were obtained from 75 penguins to determine packed cell volume (PCV), red blood cell (RBC) and white blood cell (WBC) counts, mean corpuscular volume (MCV), uric acid, total protein, albumin, globulin and aspartate aminotransferase (AST) activity levels. Whole blood samples were used for PCR assays. Plasmodium spp. was detected in 32.0% of the specimens using PCR and in 29.3% using microscopic analyses. Anorexia, diarrhea and neurological disorders were more frequent in penguins with malaria and a significant weight difference between infected and non-infected penguins was detected. PCV and MCV rates showed no significant difference. RBC and WBC counts were lower in animals with avian malaria and leukopenia was present in some penguins. Basophil and lymphocyte counts were lower in infected penguins along with high monocyte counts. There was no significant difference in AST activities between infected and non-infected animals. There was a significant increase in uric acid values, however a decrease in albumin values was observed in infected penguins. Based on this study, we concluded that Plasmodium spp. occurs in Magellanic penguins of rehabilitation centers in Southeastern Brazil, compromising the weight of infected animals with clinical alterations appearing in severe cases of this disease. It was also noted that, although the hematological abnormalities presented by these animals may not have been conclusive, leukopenia, monocytosis and the decrease of basophils and lymphocytes revealed an unfavorable prognosis, and Plasmodium spp. infections may progress with elevated uric acid concentration and low albumin levels.