Lungworm: (Dictyocaulus arnfieldi) infection in donkeys

The clinical, parasitological and pathological findings in a group of six donkeys naturally infected with D arnfieldi larvae are described. One animal had to be sacrificed at an early date because it developed pneumonia. The remaining five were unthrifty, showed mild clinical respiratory signs and had heavy strongyle infections. They had varying numbers of adult worms in the airways of the lungs and eggs were found coiled up in the smaller bronchi where they had apparently lead to an obstruction to airflow in that segment. The most striking gross pathological changes were circular discrete areas of over-inflation surrounding such bronchi. Histologically the infected bronchi exhibited a marked bronchiolitis with goblet cell hyperplasia and a mainly lymphoid inflammatory infiltrate. These areas also showed a localised bronchiolitus and overinflated alveolar tissue although true emphysema was not present. It is postulated that the parasite is well-adapted to its host and is able to survive for long periods within the lung without causing a debilitating amount of damage to the host. The immunological aspects of the infection are discussed briefly.