Aspectos parasitológicos, clínicos e hematológicos de ovinos da raça Santa Inês experimentalmente infectados por Fasciola hepatica

Abstract

Fasciola hepatica is a parasite found in the bile duct of many mammal species, causing severe morbidity and death, especially in sheep. Fasciolosis is expanding throughout Brazil, and in Minas Gerais State it has been reported natural infection in definitive hosts such as cattle, buffalos and capybaras, as well as in Lymnaea (=Pseudosuccinea) columella, one of the intermediate hosts. The economic importance of fasciolosis is associated with weight loss, dropping milk, meat and wool production, abortion and treatment costs. However, the clinical signs of this disease are not easily recognized by the owner or technician involved in the animal production system. In the past few years, sheep farming has been expanding from north to south in Brazil and Santa Inês became the most reared breed. Therefore, this study aimed to evaluate the evolution of fasciolosis in Santa Inês sheep experimentally infected with F. hepatica through parasitological, hematological and clinical parameters. 14 female lambs of Santa Inês breed aged 8 months were randomly divided into two groups: Group 1 with 9 animals individually orally inoculated with 150 metacercariaes of F. hepatica; and Group 2 with 5 non-infected animals. At 0, 15, 30, 45, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360, 390 days after infection (dai) four-sieves-technique was used to count eggs per gram of feces (EPG) in order to evaluate the dynamics of eggs eliminations in feces, and also clinical exams and hemogram. The results showed a prepatent period ranging from 60 to 62 dai, with egg elimination during the period observed. Clinical evaluation of the infected sheep revealed prostration, submandibular oedema, liver sensitivity, tachycardia, tachypnea, pale conjunctiva, loss of body condition and weight. The hemogram demonstrated normocytic normochromic and regenerative anemia, besides leukocytosis with neutrophilia and eosinophilia, with subsequent lymphocytosis. Macroscopic findings of the livers of two biopsied sheep revealed increased volume, lobes with curved edges, bleeding points distributed diffusely throughout the parenchyma, fibrin deposition in the surface of the parenchyma, dark red-colored necrotic foci, and adult worms in the bile ducts.