Isospora orlovi infection in suckling dromedary camel calves (Camelus dromedarius) in Kenya S. Bornstein a, * , I.V. Gluecks b,c , M. Younan d,e , P. Thebo a , J.G. Mattsson a a Department of Parasitology (SWEPAR), National Veterinary Institute and Swedish University of Agricultural Sciences, SE 751 89 Uppsala, Sweden b Ve ´te ´rinaires Sans Frontie `res Suisse, P.O. Box 25656, 00603 Nairobi, Kenya c Department of Veterinary Medicine, The Free University of Berlin, Germany d Ve ´te ´rinaires Sans Frontie `res Germany, P.O. Box 25653, 00603 Nairobi, Kenya e Kenya Camel Association, Nairobi, Kenya Received 4 February 2007; received in revised form 30 December 2007; accepted 8 January 2008 Abstract Outbreaks of isosporosis in young suckling dromedary camel calves (Camelus dromedarius) in Dubai, UAE and in Kenya were recently described. In the former outbreak the pathogen was shown to be Isospora orlovi by morphological features and was later characterized molecularly. In the present study, we have made a longitudinal investigation of 159 suckling dromedary calves 12 weeks of age belonging to 8 ranched camel herds (M1) in Northern Kenya. The study was carried out during 18 months. In three of the herds frequent samples were taken irregularly every 1–6 weeks. All calves 12 weeks of age present in the respective herds were sampled during the visits. In addition, 91 calves of the same age group but belonging to 42 pastoral herds (M2) in Northern Kenya were point sampled at convenience. Faecal samples from each calf were taken and the faeces were investigated for coccidia. Samples found with coccidian oocysts were suspended in a 2% potassium dichromate solution. Isospora sp. was identified and samples with relatively high numbers of Isospora sp. were analysed molecularly. The SSU rRNA gene and internal transcribed spacer 1 (ITS1) were amplified with primers complementary to conserved regions of the SSU rRNA gene in eukaryotes as well as a conserved part of the 5.8S rRNA gene of Eimeria. A relatively high number of the calves exhibited diarrhoea, 30.2% and 41.8% in the M1 and M2 herds, respectively. Isospora sp. was only found in diarrhoeic calves or in calves convalescent from recent scouring periods. No calf >8 weeks of age was found to be excreting Isospora sp. The parasite was only found in calves 4 weeks of age in the M1 herds and in the M2 herds in calves <8 weeks of age. Of the M1 and M2 calves exhibiting diarrhoea, 20.8% and 26.3% excreted Isospora sp., respectively. Morphologically the Isospora sp. was similar to I. orlovi and sequence analysis of the SSU rRNA gene from four Kenyan isolates (unfortunately only from the pastoral herds, M2) and ITS 1 segments from three of the isolates from Kenya and one from Dubai, confirmed that the Isospora isolates belonged to the species I. orlovi, and that the sequences were similar to the Dubai isolates. # 2008 Elsevier B.V. All rights reserved. Keywords: Coccidiosis; Isosporosis; Isospora orlovi; Dromedary camel calves; Camelus dromedarius; Kenya 1. Introduction Dromedary camels (Camelus dromedarius) are important domestic animals of many nomadic pastoral communities in dry lands of Africa and Asia. Although www.elsevier.com/locate/vetpar Available online at www.sciencedirect.com Veterinary Parasitology 152 (2008) 194–201 * Corresponding author. Tel.: +46 18 674000/346095; fax: +46 18 309162. E-mail addresses: set.bornstein@sva.se, set.bornstein@telia.com (S. Bornstein). 0304-4017/$ – see front matter # 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.vetpar.2008.01.004