A cross-sectional study was conducted from November 2013 to March 2014 with the purpose of determining the prevalence, identification species of lung worm circulating in the area and assessing the economic importance of lungworm infection in sheep originated from Dessie and Kombolcha districts. Coproscopic examination was conducted on 477 sheep kept under extensive and semi- intensive management systems. Of these examined animals, 218 were found to harboring lungworm parasites with an overall prevalence of 45.71%. The prevalence of species of lung worm in infected sheep was Muellerius capillaris (23.48%), Dictyocaulus filaria (8.18%), Protostrongylus rufescens (5.87%) and mixed infection (8.18%) either with two or three species. There was statistically significant difference (p<0.05) observed in infection rates between the two study sites. There was statistically significant difference (X2=32.2, P= 0.000) observed between male and female animals with prevalence of 13.4% and 24.5%, respectively. Prevalence of 19.84%, 41.67% and 69, 01% was found in animals of age groups <1year, 1-3 years and above 3years, respectively. There was statistical variation (X2=72.561, p=0.000) among the age groups. In this study, animals with poor body condition were highly infected with significant difference (X2=113.66, p=0.000) than medium and good body conditions. Sheep showing respiratory clinical syndromes, kept under extensive management system and sampled during wet season when compared with those sheep that without respiratory syndrome, kept under semi-intensive management system and sampled in dry season showed statistically significant variation(p<0.05). In addition to these, annual financial loss due to lungworm infection in sheep in Dessie municipal abattoir was assesed based on five years (2008-2012) retrospective data. The annual financial loss was estimated to be 8,046831.00 ETB, equivalent to 434963.84 USD. In conclusion, Coproscopic examination and retrospective abattoir survey revealed that lungworm parasites that infect sheep in the area induce heavy economic loss. Therefore, emphasis should be given for the prevention and control measures to mitigate the infection.

Keywords: Baermann technique, Dessie, Kombolcha, Lungworms, Prevalence, Risk factors