Serosurvey of West Nile virus (WNV) in free-ranging raptors from Brazil.

West Nile virus (WNV) is a mosquito-borne Flavivirus that can affect birds, horses, and humans, and is the only zoonotic Flavivirus that has been identified in six continents. In Brazil, until 2010, there was no evidence of WNV circulation. Recently, the virus was isolated from a horse with encephalitis, and the first human cases were registered in Brazil. Despite that, there is still no information on the enzootic cycle of this virus in birds or wildlife. This study aimed to investigate whether there is evidence of WNV circulation among wild birds from Southern Brazil. For this, we used free-living wild raptors (live-trapped or rescued) as potential sentinels to investigate the presence of WNV antibodies using ELISA and plaque reduction neutralization test (PRNT) assay. In addition, the presence of nucleic acids from Flavivirus family members was investigated. None of the birds sampled presented clinical findings compatible with WNV. Of the 200 serum samples from birds of prey belonging to 21 species, ten (5%) were positive for the presence of WNV antibodies on ELISA testing. The PRNT test did not confirm the ELISA results, but indicated that three birds had possibly been exposed to Saint Louis encephalitis virus (SLEV). All samples were negative for Flavivirus RNA. The results presented here evince the need for permanent surveillance for emerging flaviviruses in Brazil, as well as for a contingency policy in the case of human/animal outbreaks, particularly in high-risk areas.

Plasma carotenoids and immunity in a despotic avian scavenger.

Carotenoids are pigmented compounds acquired through diet that have important functions as antioxidants and immune modulators. We studied the association between immunity and circulating carotenoids in Andean condors (Vultur gryphus). We evaluated the relationship between α-, ß-, and γ-globulin blood concentrations and different circulating carotenoids in two groups of Andean condors that differ in their mean health status, rehabilitating (suffering different pathologies), and wild individuals (trapped when displaying their physiological behavior). In rehabilitating individuals, α-, ß-, and γ-globulin concentrations were higher than in wild individuals. This shows that rehabilitating individuals were developing an immune response associated with the pathologies that they were suffering at the time of sampling. In addition, circulating carotenoids were lower in rehabilitating than in wild individuals. We found negative correlations between α-, ß-, and γ-globulins and different circulating carotenoids in rehabilitating individuals, but not in wild condors. Xanthophylls were strongly related to α-, ß-, and γ-globulin blood concentrations in rehabilitating, but not in wild condors. Our results suggest that there is a potential relationship between circulating carotenoids and immunity in the Andean condor. Given that this species may display a carotenoid-based pigmentation, our results could suggest that a trade-off between the immune system and external coloration could operate in this species, which may have implications in their access to food resources and mate selection and, thus, in their conservation.

Toxoplasma gondii infection in raptors from Italy: Seroepidemiology and risk factors analysis.

Toxoplasma gondii is a zoonotic parasite infecting a wide range of intermediate hosts, including birds. Nevertheless, scant information on the spread of infection in wild bird populations is available to date. With the aim of updating information on T. gondii infection in birds of prey and possible risk factors associated with the infection, a serosurvey was planned on both wild and captive raptors. An overall of 93 raptors from Northern Italy were tested for the presence of anti-T. gondii antibodies with a commercial modified agglutination test (MAT). A T. gondii prevalence of 10.7% was recorded; the highest seroprevalence was observed within the Family Strigidae (12.5%). Only wild animals tested positive; any statistical difference among species, taxonomic family, age, origin, use, migratory behavior and diet composition was not highlighted. Toxoplasmosis in birds of prey, sentinel species for the environmental spread of T. gondii, should always be considered within sanitary programs devoted to avian species protection.

Anticorpos anti-Toxoplasma gondii em carcarás (Caracara plancus) procedentes da região aeroportuária do Recife, Pernambuco, Brasil / Antibodies to Toxoplasma gondii in Crested Caracara (Caracara plancus) from Recife Airport, Pernambuco, Brazil

Objetivou-se com este estudo pesquisar a ocorrência de anticorpos anti-Toxoplasma gondii em carcarás (Caracara plancus) capturados no Aeroporto Internacional do Recife/Guararapes Gilberto Freyre, Pernambuco, Brasil. Foram analisadas 115 amostras de soros sanguíneos pelo teste de aglutinação modificada (IgG, MAT≥25) utilizando taquizoítos inativados em formalina. Do total de amostras analisadas, 5,21% (6/115) foram positivas para presença de anticorpos anti-T. gondii, 16,67% com título 1:25 (1/06) e 83,33% (5/06) com título 1:50. A ocorrência de anticorpos em carcarás procedentes de região aeroportuária fomenta a preocupação em relação a aspectos ainda pouco elucidados, relacionados principalmente à inserção de aves silvestres na cadeia epidemiológica da toxoplasmose conectada à ação antrópica, tornando próxima a interação entre animais silvestres, domésticos e o homem. Dessa forma, é notória a necessidade de estudos relacionados à dinâmica de transmissão entre os diferentes genótipos existentes nessa tríade e sua relação com o meio ambiente, a fim de determinar a influência dessa espécie animal na cadeia epidemiológica da toxoplasmose.(AU)

The objective of this study was to investigate the occurrence of antibodies against Toxoplasma gondii in carcarás (Caracara plancus) captured in the Recife/Guararapes Gilberto Freyre International Airport, in the State of Pernambuco, Brazil. 115 samples of blood sera were tested by the Modified Agglutination Test technique (IgG, MAT > 25) using tachyzoites inactivated in formalin. Of the total of the analyzed samples, 5,21% (6/115) were positive for the presence of antibodies against T. gondii, 16,67% with a titer of 1:25 (1/06) and 83,33% (5/06) with a titration of 1:50. The occurrence of antibodies in caracaras coming from airport region generate concern about aspects still poorly understood, mainly related to the inclusion of wild birds in the epidemiological chain of toxoplasmosis connected to human action, making close interaction between wild animals, domestic and man. Thus, the need for studies related to the dynamics of transmission between the different existing genotypes in this triad is evident as is its relationship with the environment to determine the influence of this animal species in the epidemiological chain of toxoplasmosis.(AU)

Determinants and short-term physiological consequences of PHA immune response in lesser kestrel nestlings.

Individual immune responses are likely affected by genetic, physiological, and environmental determinants. We studied the determinants and short-term consequences of Phytohaemagglutinin (PHA) induced immune response, a commonly used immune challenge eliciting both innate and acquired immunity, on lesser kestrel (Falco naumanni) nestlings in semi-captivity conditions and with a homogeneous diet composition. We conducted a repeated measures analyses of a set of blood parameters (carotenoids, triglycerides, ß-hydroxybutyrate, cholesterol, uric acid, urea, total proteins, and total antioxidant capacity), metabolic (resting metabolic rate), genotypic (MHC class II B heterozygosity), and biometric (body mass) variables. PHA challenge did not affect the studied physiological parameters on a short-term basis (<12 hr), except plasma concentrations of triglycerides and carotenoids, which decreased and increased, respectively. Uric acid was the only physiological parameter correlated with the PHA induced immune response (skin swelling), but the change of body mass, cholesterol, total antioxidant capacity, and triglycerides between sessions (i.e., post-pre treatment) were also positively correlated to PHA response. No relationships were detected between MHC gene heterozygosity or resting metabolic rate and PHA response. Our results indicate that PHA response in lesser kestrel nestlings growing in optimal conditions does not imply a severe energetic cost 12 hr after challenge, but is condition-dependent as a rapid mobilization of carotenoids and decrease of triglycerides is elicited on a short-term basis.

Cellular and humoral immunodepression in vultures feeding upon medicated livestock carrion.

Veterinary pharmaceuticals contained in dead livestock may be ingested by avian scavengers and negatively affect their health and consequently their population dynamics and conservation. We evaluated the potential role of antibiotics as immunodepressors using multiple parameters measuring the condition of the cellular and humoral immune system in griffon (Gyps fulvus), cinereous (Aegypius monachus) and Egyptian vultures (Neophron percnopterus). We confirmed the presence of circulating antimicrobial residues, especially quinolones, in nestlings of the three vulture species breeding in central Spain. Individuals ingesting antibiotics showed clearly depressed cellular and humoral immune systems compared with nestlings from the control areas, which did not ingest antibiotics. Within central Spain, we found that individuals with circulating antibiotics showed depressed cellular (especially CD4(+)and CD8(+)T-lymphocyte subsets) and humoral (especially acellular APV complement and IL8-like) immune systems compared with nestlings without circulating antibiotics. This suggests that ingestion of antibiotics together with food may depress the immune system of developing nestlings, temporarily reducing their resistance to opportunistic pathogens, which require experimental confirmation. Medicated livestock carrion should be considered inadequate food for vultures due to their detrimental consequences on health derived from the ingestion and potential effects of the veterinary drugs contained in them and for this reason rejected as a management tool in conservation programmes.

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-beta1 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.