■ INTRODUCTION Piroplasmosis are tick-borne diseases due to protozoa belonging to two genera, Babesia and Theileria. These infections cause high losses in many countries (Minjauw and McLeod, 2003) and have an important impact, particularly since a high proportion occurs in farms with limited resources. Moreover, the infections are frequently asymptomatic leading to low but persistent losses for many years. In North Africa, four species of piroplasms have been described, namely Theileria annulata, Babesia bovis, B. bigemina and B. divergens , of which the first three species cause high losses in cattle (Flach and Ouhelli, 1992; Flach et al., 1995; Gharbi et al., 2006; Darghouth, 2008; Gharbi et al., 2011). In Algeria, numerous epidemiological and parasitological studies have been carried out more than 70 years ago (Sergent et al., 1945) and led to the development of the first live atten- uated vaccine, using the Theileria annulata strain ‘Kouba’. This vac- cine has been used to immunize thousands of animals in Morocco, Algeria and Tunisia. Since this period, few studies have been performed in Algeria despite the probable high socio-economic impact of these infections and the high incidence of clinical cases. There is a gap in recent knowledge ■ SANTÉ ANIMALE ET ÉPIDÉMIOLOGIE 105 Revue d’élevage et de médecine vétérinaire des pays tropicaux, 2017, 70 (3) : 105-110 Bovine piroplasmosis in the provinces of Skikda and Oum El Bouaghi (Northeastern Algeria): Epidemiological study and estimation of milk yield losses Mohamed Chérif Benchikh Elfegoun 1* Mohamed Gharbi 2 Zehira Merzekani 1 Karima Kohil 1 Summary During a survey carried out in 88 farms located in two provinces of Northeast- ern Algeria – Oum El Bouaghi and Skikda –, 89 clinical cases of piroplasmosis (i.e. an 11.6% infection rate in the examined cattle) were reported between May and September 2011 in 86.4% of the visited farms. Three species of piroplasms were identified in the blood films stained with Giemsa: Theileria annulata (in 94.0% of the sick animals), Babesia bovis (33.7%) and Babesia bigemina (3.4%), with 31% of co-infections. No significant difference was observed in the prev- alence between the two provinces, nor between cattle breeds. Tropical theile- riosis caused a significant drop in milk production estimated at 319 liters per infected cow during the two months following the disease. Seven tick species were collected in the farms during the study period. The infestation peak was observed in July for Hyalomma scupense (syn. H. detritum), H. lusitanicum, H. anatolicum, Rhipicephalus bursa and R. turanicus, and in August for H. margin- atum and H. excavatum. A positive correlation was observed between clinical cases of tropical theileriosis and H. scupense infestation on one hand, and clini- cal cases of babesiosis and R. bursa infestation on the other hand. ■ How to quote this article : Benchikh Elfegoun M.C., Gharbi M., Merzekani Z., Kohil K., 2017. Bovine piro- plasmosis in the provinces of Skikda and Oum El Bouaghi (Northeastern Algeria): Epidemiological study and estimation of milk yield losses. Rev. Elev. Med. Vet. Pays Trop., 70 (3): 105-110, doi: 10.19182/remvt.31519 1. Laboratoire de parasitologie, Institut des sciences vétérinaires, Université Mentouri, 25000 Constantine, Algeria. 2. Laboratoire de parasitologie, Université Manouba, Institution de la recherche et de l’enseignement supérieur agricole, Ecole nationale de médecine vétérinaire de Sidi Thabet, Sidi Thabet, Tunisie. * Corresponding author Tel.: +213 31 655 232; Email: blmc25@yahoo.fr https://creativecommons.org/licenses/by/4.0/ Keywords Cattle, Babesia bigemina, Babesia bovis, Theileria annulata, piroplasmosis, Algeria Submitted: 24 May 2016 Accepted: 12 January 2018 Published: 12 March 2018 DOI : 10.19182/remvt.31519