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Pesquisa e identificação de filarídeos em cães residentes nos distritos de Évora e Portalegre
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Abstract(s)
As microfilárias são a fase larvar dos filarídeos que pertencem à Família
Onchocercidae. Estas são expulsas pelos parasitas adultos na circulação sanguínea, sendo
assim possível visualizar em amostras de sangue se existir microfilarémia. Em Portugal
há quatro parasitas cujas microfilárias se podem ver em amostras de sangue, Dirofilaria
immitis, Dirofilaria repens, Acanthocheilonema reconditum e Acanthocheilonema
dracunculoides. Estas apresentam diferente patogenia, sendo a mais conhecida e mais
patogénica a espécie Dirofilaria immitis. As microfilárias das diferentes espécies
apresentam diferentes caraterísticas fisiológicas e morfológicas, sendo possível, através
da observação destas, identificá-las e diagnosticar corretamente o animal infetado. Neste
estudo, foram colhidas e observadas 180 amostras de sangue de cães dos distritos de
Évora e Portalegre, com o objetivo de caraterizar os animais infetados, identificar casos
assintomáticos, avaliar a distribuição de casos positivos nestes distritos e testar técnicas
laboratoriais, sorológicas e moleculares para identificação de microfilárias. Foram
realizadas a técnica de gota fresca, esfregaço sanguíneo com recurso à coloração Diff-
Quick e técnica de Knott modificada em todas as amostras. Foi ainda realizado PCR e
eletroforese nos animais em que foi detetada microfilarémia. Estas técnicas mostraram
ter diferentes vantagens e desvantagens para a diferenciação morfológica das
microfilárias, e todas mostraram a necessidade de realizar mais do que uma técnica para
este efeito. De 180 amostras, em nove foi detetada microfilarémia por observação do
sangue ao microscópio pelas técnicas referidas. Destes positivos, sete eram machos e
dois eram fêmeas, e apenas quatro positivos apresentaram sinais clínicos, sendo os
restantes cinco assintomáticos. Através de PCR e eletroforese duas amostras deram
resultado inconclusivo, e foi detetado um falso negativo num teste sorológico.
Concluindo que animais infetados podem ser assintomáticos, sendo imprescindível a
realização de testagens de rotina, para detetar estas infeções de forma precoce,
utilizando diferentes técnicas de diagnóstico, por estas mostrarem diferentes graus de
eficácia.
Microfilariae are the larval stage of filarids that belong to the family Onchocercidae. They are expelled by the adult parasites into the bloodstream, so it is possible to see them in blood samples if there is microfilariaemia. In Portugal there are four parasites whose microfilariae can be detected in blood samples: Dirofilaria immitis, Dirofilaria repens, Acanthocheilonema reconditum and Acanthocheilonema dracunculoides. These show different pathogenesis, the best known and most pathogenic being Dirofilaria immitis. The microfilariae of the different species have different physiological and morphological characteristics, and it is possible to identify and correctly diagnose the infected animal by looking at them. In this study, 180 blood samples were collected and observed from dogs in the districts of Évora and Portalegre, aiming to characterize the infected animals, identify asymptomatic cases, evaluate the distribution of positive cases in these districts and test laboratory, serological and molecular techniques for microfilariae identification. The fresh drop technique, blood smear using Diff-Quick staining and modified Knott's technique were performed on all samples. PCR and electrophoresis were also performed in animals in which microfilariaemia was detected. These techniques showed different advantages and disadvantages for the morphological differentiation of microfilariae, and all showed the need to perform more than one technique for this purpose. Of 180 samples, in nine microfilariaemia was detected by microscopic observation of the blood by the above techniques. Of these positives seven were males and two were females, and only four positives showed clinical signs, and the remaining five were asymptomatic. Through PCR and electrophoresis two samples gave inconclusive results, and one false negative was detected in a serological test. In conclusion, infected animals can be asymptomatic, and routine testing is essential to detect these infections early, using different diagnostic techniques, as they show different degrees of effectiveness.
Microfilariae are the larval stage of filarids that belong to the family Onchocercidae. They are expelled by the adult parasites into the bloodstream, so it is possible to see them in blood samples if there is microfilariaemia. In Portugal there are four parasites whose microfilariae can be detected in blood samples: Dirofilaria immitis, Dirofilaria repens, Acanthocheilonema reconditum and Acanthocheilonema dracunculoides. These show different pathogenesis, the best known and most pathogenic being Dirofilaria immitis. The microfilariae of the different species have different physiological and morphological characteristics, and it is possible to identify and correctly diagnose the infected animal by looking at them. In this study, 180 blood samples were collected and observed from dogs in the districts of Évora and Portalegre, aiming to characterize the infected animals, identify asymptomatic cases, evaluate the distribution of positive cases in these districts and test laboratory, serological and molecular techniques for microfilariae identification. The fresh drop technique, blood smear using Diff-Quick staining and modified Knott's technique were performed on all samples. PCR and electrophoresis were also performed in animals in which microfilariaemia was detected. These techniques showed different advantages and disadvantages for the morphological differentiation of microfilariae, and all showed the need to perform more than one technique for this purpose. Of 180 samples, in nine microfilariaemia was detected by microscopic observation of the blood by the above techniques. Of these positives seven were males and two were females, and only four positives showed clinical signs, and the remaining five were asymptomatic. Through PCR and electrophoresis two samples gave inconclusive results, and one false negative was detected in a serological test. In conclusion, infected animals can be asymptomatic, and routine testing is essential to detect these infections early, using different diagnostic techniques, as they show different degrees of effectiveness.
Description
Keywords
microfilárias Évora Técnica de Knott modificada Dirofilaria; Acanthocheilonema microfilariae Modified Knott’s technique Portalegre
Citation
Hermann, S.S.(2022).Pesquisa e identificação de filarídeos em cães residentes nos distritos de Évora e Portalegre. Escola Superior Agrária de Elvas. Elvas
Publisher
Escola Superior Agrária de Elvas