Contents lists available at ScienceDirect Parasitology International journal homepage: www.elsevier.com/locate/parint Short communication Prevalence and molecular subtyping of Blastocystis from dairy cattle in Kanagawa, Japan Aya Masuda, Toshiaki Sumiyoshi, Tadatoshi Ohtaki, Jun Matsumoto ⁎ Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan ARTICLE INFO Keywords: Blastocystis Dairy cattle Subtypes ABSTRACT Blastocystis is an intestinal protist, commonly found in the human population and in a wide range of animals globally. Currently, isolates from mammalian and avian hosts are classified into 17 subtypes (STs) based on phylogeny of the small subunit rRNA gene (SSU rDNA), of which ten (ST1-9, 12) are reported in humans. ST10 is a major ST reported from livestock cattle. However, other STs including ST1, 3, 4, 5, and 6, which have the potential to be transmitted to humans, are also reported from cattle in several countries. Although a survey has been conducted previously in western Japan for livestock cattle, there is no information available regarding other parts of Japan. Therefore, this study surveyed the prevalence of Blastocystis and its STs in cattle from Kanagawa prefecture, eastern Japan. Fecal specimens, collected from 133 dairy cattle on four different farms, were subjected to a short-term xenic in vitro culture and Blastocystis were identified by microscopic examination. Seventy-two cattle were positive for Blastocystis (54.1%). Direct sequences for the partial SSU rDNA were ob- tained for 45 samples. Based on nucleotide sequence homology search and phylogenetic analysis, 44 isolates were identified as ST14 and one as ST10. Our study confirms the presence of these STs in dairy cattle in Japan for the first time. The STs identified here, ST10 and ST14, support previous findings that Bovidae may be the natural host for both STs. Blastocystis is an intestinal protist, taxonomically placed under Stramenopiles [1], and commonly found in humans and a vast range of animal species. Despite intensive studies in recent years, details in- cluding morphology and pathology of this parasite are still largely unknown. Recent molecular techniques have revealed a high genetic diversity of the parasite and isolates from various hosts are classified into different subtypes (STs) based on phylogeny of the small subunit rRNA gene (SSU rDNA). Currently, isolates from mammalian and avian hosts are classified into 17 STs, ten of which (ST1-9, 12) are reported in humans [2, 3]. Although asymptomatic carriage is common, infection with the parasite is also associated with non-specific gastrointestinal symptoms, including diarrhea, nausea, vomiting, abdominal pain, and irritable bowel syndrome [4]. STs that are isolated from humans are also commonly found in various animal groups, such as ST1-3 in non-human primates, ST1 and ST5 in Artiodactyla, and ST6 and ST7 in avian species [5]. This suggests that some STs may have low host specificity and could cause zoonotic transmission. Higher prevalence of the infection of certain STs was reported among animal handlers compared to those who do not have contact with animals [6, 7]. Conversely, there are STs, such as ST10 and ST14, which are commonly found in livestock cattle, but not yet re- ported in humans [5]. Therefore, understanding ST distribution in an- imal hosts is crucial as certain STs may be of zoonotic importance. Cattle are suggested to be the natural host for ST10 and ST14, although ST1 also seems to be common and could potentially be transmitted to humans [8]. In Japan, prevalence of Blastocystis in livestock cattle in western parts was 71%, and ST1, 3, and 5 were identified among these samples [9–11]. However, the study surveyed only western parts of Japan wherein ten STs (ST8-17) were not identified at that time. Therefore, this study aims to survey the prevalence and ST-identifica- tion of Blastocystis in livestock cattle in eastern Japan for the first time. These additional data could provide information on host specificity of the parasite and may be of important use for the livestock handlers in this area who are at risk of infection. A fecal specimen was collected directly from the rectum of 133 dairy cattle between June and December 2017 on four different farms; A, B, C, and D located within a 10-km radius in Kanagawa prefecture, Japan. The number of samples from each farm were 34, 25, 44, and 30, https://doi.org/10.1016/j.parint.2018.07.005 Received 13 March 2018; Received in revised form 4 July 2018; Accepted 4 July 2018 ⁎ Corresponding author at: Laboratory of Medical Zoology, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan. E-mail addresses: aya.masuda@nihon-u.ac.jp (A. Masuda), sumiyoshi.toshiaki@nihon-u.ac.jp (T. Sumiyoshi), ohtaki.tadatoshi@nihon-u.ac.jp (T. Ohtaki), matsumoto.jun82@nihon-u.ac.jp (J. Matsumoto). Parasitology International 67 (2018) 702–705 1383-5769/ © 2018 Elsevier B.V. All rights reserved. T