Banca de QUALIFICAÇÃO: ALEXANDRE CARVALHO COSTA

Correlation between filarial infection and hematological and clinical alterations in green-winged saltators (Saltator similis).

Filariasis, Hematology, PCR

Among the native passerines, the green-winged saltator (Saltator similis, order Passeriformes, family Thraupidae) is the second species with the highest occurrence in apprehensions and the first when it comes to interest among bird breeders. Passeriformes are affected by filaridae of the Onchocercidae family of worldwide distribution, which are thread-shaped nematode helminths capable of parasitizing tissues and cavities of birds and other groups of animals (mammals, reptiles and amphibians). They are transmitted in the larval stage (microfilaria) through the bite of insects and hematophagous arthropods. It is possible to observe microfilariae in the peripheral blood and lung, while the adult filarial can be found in the coelomic cavity and in several tissues. Although most species of Filaridae are not pathogenic for birds, there are reports of cases in Passeriformes, Piciformes, Psittaciformes, Falconiformes, Gruiformes and Podicipediformes, where some clinical alterations were observed, among them, weight reduction, ataxia and death. Due to the intermittent release of microfilariae into the bloodstream, the diagnosis can be made through serial evaluations of the blood smear. Molecular methods, such as the polymerase chain reaction (PCR), can be used to detect and identify the filarial species present in the definitive host, however, there are few studies that address the molecular characterization and phylogeny of adult avian filaridae, and the scarce information is sometimes insufficient for a conclusive diagnosis. In birds there are about 160 species of filarids described in 16 genera, but only six species of the Onchocercidae family have DNA sequences available for phylogenetic analysis, they are: Chandlerella quiscali, Splendidofilaria sp., Eulimdana clava, Cardiofilaria pavlovskyi, Aproctella alessandroi, Pelecitus fulicaeatrae. Despite the great diversity of species of this family in birds, information about these filarids is scarce. As so, it is crucial to be able to understand the pathological and clinical consequences that involve avian filarial infections, being able to determine the real impact on the host population. Given these facts, the objective of the present study is to investigate the presence of microfilariae in greeen-wiged saltator kept at the Centro de Triagem de Animais Silvestres (CETAS) through blood smears and PCR and to correlate the findings with possible hematological changes and clinical signs observed. In this way, it is hoped to obtain information that will help in the diagnosis and treatment of these birds and, thus, improve the quality of life and contribute to a possible reintroduction into wildlife. The green-wiged saltator used in the study came from seizures between 2021 and 2023, and are currently being kept at CETAS, located in the city of Seropédica - RJ. Individuals without distinction of sex, age and health status were included. The birds are physically restrained, weighing is carried out followed by clinical examination and all data are documented in clinical records. Afterwards, the collection is performed, obtaining a blood volume of approximately 0.3 mL for performing a blood count and PCR. A drop of blood directly from the syringe is used to make blood smears, where a scan will be carried out for research and quantification of microfilariae. Immediately after collection, fluid therapy is performed subcutaneously in all birds. In the PCR reaction, partial sequences of the mitochondrial genes cytochrome c oxidase I (cox1) and nuclear 28S rDNA (28S) will be used and for the amplification of both genes the PCR mix will be used, where the final volume is 25 µL per reaction. The primers COIintF and COIintR will be used to amplify a fragment of approximately 650 bp of cox1, and the primers Nematode 1 and Nematode 2 to amplify a fragment of approximately 750 bp of 28S. Statistical analysis will be performed using Student's T test to determine whether there is a difference between the means of a given characteristic of two independent groups (negative and positive for microfilaria). Hematological parameters and clinical signs will be analyzed using the Kolmogoroy-Sminorv normality test (for more than 50 samples). When these data are normally distributed (above < 0.05), they will be analyzed using analysis of variance (ANOVA) at a 5% significance level. However, when there is no normal distribution of data, they will be analyzed using the non-parametric Mann-Whitney test at a 5% significance level. For the association between positive and negative animals with hematological changes and clinical signs, the Chi-Square or Fisher's Exact test will be used at 5% of significance.