Evaluation of serum chemistry values associated with avian malaria infections in African black-footed penguins (Spheniscus demersus)

Clinical Chemistry and Haematology Values of a Captive Population of Humboldt Penguins (Spheniscus humboldti)

Reference intervals for clinical chemistry and haematology analytes are essential for the interpretation of blood results, but limited data are available for Humboldt penguins (Spheniscus humboldti) in zoological collections as well as in the wild. The aim of the present study was therefore to establish reference intervals for a series of clinical chemistry and haematology analytes in a single zoological population of Humboldt penguins. Furthermore, possible variations of the analytes influenced by the age and sex of the individuals were investigated. Lithium heparinized plasma and whole blood samples from 39 animals were analysed and statistically evaluated. The following clinical chemistry analytes were significantly higher in females: glutamate dehydrogenase (p = 0.0003), alanine transaminase (p = 0.0005), alkaline phosphatase (p = 0.0245), aspartate aminotransferase (p = 0.0043), creatine kinase (p = 0.0016), lactate dehydrogenase (p < 0.0001), inorganic phosphorus (p = 0.0223), and sodium (p = 0.0415). No significant differences between males and females were found for any haematology analyte. Cholesterol (p = 0.0233; -0.39), white blood cell count (p = 0.0208; -0.40), and absolute heterophiles (p = 0.0148; -0.42) had significant negative correlations with the age of the penguins. The results indicate that the factors of sex and age should be considered when interpreting the results of haematological and clinical biochemistry assays, and further studies are needed to determine whether there are more differences in other age groups or seasons.

Hematology and Blood Chemistry Reference Values of Captive Adult Black-Faced Ibis (Theristicus melanopis melanopis)

Hematology and blood chemistry reference values in wildlife animals are considered a key element to evaluate their health and welfare status. The incidence of birds rescued is increasing, thus, rehabilitation centers worldwide need valid reference values to improve medical care for wild individuals. The objective of this study was to obtain the reference values of the adult black-faced ibis (Theristicus melanopis). Blood was taken from adult rehabilitated birds and analyzed to obtain red and white line values such as hematocrit, hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), heterophils, lymphocytes, monocytes, eosinophils and basophils. Values for blood glucose, proteins, albumin, globulin, calcium, phosphorus, blood urea nitrogen (BUN), creatinine, alkaline phosphatase, aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH), creatine phosphokinase (CPK) and albumin:globulin (A/G) ratio were also obtained. The results were similar to others reported for species of the Threskiornithidae family (bald, glossy and Puna ibises), but showed higher values for white blood cells (WBC), heterophils, monocytes and heterophil-lymphocyte (H/L) ratio, but lower values for basophils and eosinophils. Moreover, higher values in albumin, BUN and CPK were observed. This is the first report of the hematology references values for the black-faced ibis showing differences to other closely related species. The results may be of use in rescue and rehabilitation centers for animal welfare and health assessments of the black-faced ibis.

Clinical biochemistry of rescued Magellanic Penguins (Spheniscus magellanicus): serum or heparinized plasma?

ABSTRACT In the last few years, an increasing number of debilitated Magellanic penguins (Spheniscus magellanicus) has been rescued and taken to rehabilitation centers on Brazil’s southern coast to be clinically treated and evaluated for re-introduction. This work aims to compare the viability of heparinized plasma with the viability of serum for biochemistry analyses under rehabilitation conditions. Blood sampled from 31 physically healthy rescued penguins was processed into serum/plasma-paired samples and analyzed for 12 biochemical parameters: alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), cholesterol (CHOL), creatine kinase (CK), gamma-glutamyl transpeptidase (GGT), glucose, (GLU) lactate dehydrogenase (LDH), total proteins (TP), triglycerides (TG), urea (UR), and uric acid (UA).The results showed that six paired samples presented visual signs of hemolysis (visual hemolytic score≥1), four of which occurred exclusively in the serum counterpart. Significant differences (P≤ 0.5) between sample types were found for CHOL (3%), GLU (6%) and TG (52%). Only TG was considered clinically relevant (>10%). All mean/median results fell within the available reference intervals by the Association of Zoos and Aquariums (Penguin, 2014). In conclusion, we verified that heparinized plasma is a viable sample for the clinical biochemistry of rescued Magellanic penguins as it yields compatible results with serum, while providing practical benefits. The adoption of this practice favors a faster bird recovery, by minimizing blood sampling volume, and optimizes material resources, allowing use of the same collector tube as for hematology.

Malaria in penguins - current perceptions

Avian malaria is a mosquito-borne disease caused by protozoans of the genus Plasmodium, and it is considered one of the most important causes of morbidity and mortality in captive penguins, both in zoological gardens and rehabilitation centres. Penguins are known to be highly susceptible to this disease, and outbreaks have been associated with mortality as high as 50-80% of affected captive populations within a few weeks. The disease has also been reported in wild penguin populations, however, its impacts on the health and fitness of penguins in the wild is not clear. This review provides an overview of the aetiology, life cycle and epidemiology of avian malaria, and provides details on the strategies that can be employed for the diagnostic, treatment and prevention of this disease in captive penguins, discussing possible directions for future research.

Establishment of baseline haematology and biochemistry parameters in wild adult African penguins (Spheniscus demersus)

There are few publications on the clinical haematology and biochemistry of African penguins (Spheniscus demersus) and these are based on captive populations. Baseline haematology and serum biochemistry parameters were analysed from 108 blood samples from wild, adult African penguins. Samples were collected from the breeding range of the African penguin in South Africa and the results were compared between breeding region and sex. The haematological parameters that were measured were: haematocrit, haemoglobin, red cell count and white cell count. The biochemical parameters that were measured were: sodium, potassium, chloride, calcium, inorganic phosphate, creatinine, cholesterol, serum glucose, uric acid, bile acid, total serum protein, albumin, aspartate transaminase and creatine kinase. All samples were serologically negative for selected avian diseases and no blood parasites were detected. No haemolysis was present in any of the analysed samples. Male African penguins were larger and heavier than females, with higher haematocrit, haemoglobin and red cell count values, but lower calcium and phosphate values. African penguins in the Eastern Cape were heavier than those in the Western Cape, with lower white cell count and globulin values and a higher albumin/globulin ratio, possibly indicating that birds are in a poorer condition in the Western Cape. Results were also compared between multiple penguin species and with African penguins in captivity. These values for healthy, wild, adult penguins can be used for future health and disease assessments.

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.

PRELIMINARY RESULTS OF AN ANTICIRCUMSPOROZOITE DNA VACCINE TRIAL FOR PROTECTION AGAINST AVIAN MALARIA IN CAPTIVE AFRICAN BLACK-FOOTED PENGUINS (SPHENISCUS DEMERSUS)

Captive juvenile African black-footed penguins (Spheniscus demersus) housed in an outdoor enclosure at the Baltimore Zoo have an average 50% mortality from avian malarial (Plasmodium sp.) infection each year without intense monitoring for disease and chemotherapeutic intervention. During the 1996 malaria transmission season, the safety and efficacy of an anti-circumsporozoite (CSP) DNA vaccine encoding the Plasmodium gallinaceum CSP protein against P. relictum were studied. The goal was to reduce clinical disease and death without initiating sterile immunity after release into an area with stable, endemic avian malaria. The birds were monitored for adverse clinical signs associated with vaccination, the stimulation of an anti-CSP antibody response, and protection afforded by the vaccine. The presence of P. relictum in trapped culicine mosquitoes within the penguin enclosure was monitored to assess parasite pressure. Among the vaccinated penguins, the parasitemia rate dropped from approximately 50% to approximately 17% despite intense parasite pressure, as determined by mosquito infection rate. During the year of the vaccine trial, no mortalities due to malaria occurred and no undesirable vaccination side effects occurred. This is the first trial of an antimalarial vaccine in a captive penguin colony.

Plasmodium Juxtanucleare associated with mortality in black-footed penguins (Spheniscus demersus) admitted to a rehabilitation center

Five black-footed penguins (Spheniscus demersus) admitted to the Southern African Foundation for the Conservation of Coastal Birds, in Cape Town, South Africa, died from malaria infection. Evidence for malaria as the cause of death included antemortem clinical signs, parasitemia, splenomegaly, pulmonary edema, and the presence of histologically visible schizonts in the reticuloendothelial system. A portion of the malarial small subunit ribosomal ribonucleic acid gene was detected by polymerase chain reaction from postmortem blood samples from all the birds. A species-specific variable region of this gene was compared with the same region on genes from other known avian malarial organisms, establishing that Plasmodium juxtanucleare was involved.

Value of antigen and antibody detection, and blood evaluation parameters in diagnosis of avian invasive aspergillosis

The applicability of ELISA detection of circulating Aspergillus spp. antigen (Ag) and systemic antibody (Ab) of IgG class, and the blood parameter values were evaluated for diagnosis of invasive aspergillosis in Aspergillus spp.-challenged Peking ducks (Anas platyrhynchos). The protective role of Aspergillus spp. IgG was evaluated in Cape shelducks (Tadorna cana) immunized with Aspergillus spp. Ag. Challenged but non-immunized A. platyrhynchos developed invasive aspergillosis on day 21 as demonstrated histopathologically by the presence of fungal micro-granuloma in air sacs and lung tissue, with serum antigenemia fluctuating from 65 to 270 ng of 55-kD basic protein Ag per ml. Immunized A. platyrhynchos did not demonstrate Aspergillus spp. serum antigenemia but did show rare histopathological changes in some air sacs associated with fungal inflammation. Although the differences between immunized and non-immunized T. cana in blood evaluation parameters did not differ significantly, immunized birds mounted high Aspergillus spp.-specific IgG titer. There was no correlation between the blood parameter values and post-immunization timepoints in T. cana and in A. Platyrhynchos. Intramuscular immunization with Aspergillus spp. mycelial phase cultures Ag provided protection against the pathogens. The lack of relations between blood parameter values and increasing Aspergillus spp. IgG titers (in T. cana and A. platyrhynchos) indicate low applicability of these parameters in evaluation of a bird Aspergillus spp. status. Detection of circulating 55-kDa Aspergillus spp. Ag has high early predictive values for invasive aspergillosis in birds.