1. INTRODUCTION
Equine piroplasmosis (EP) is a tick-borne protozoal disease in which horses, mules, donkeys, and zebras are infected with the blood apicomplexans, Babesia caballi or Theileria equi from blood-sucking ticks (Onyiche et al., 2019; Ozubek & Aktas, 2018; Souza et al., 2019; Wise, Kappmeyer, Mealey, & Knowles, 2013). EP is not a fatal disease, but it causes serious economic damage and an important obstacle to international trade as major diseases designated by World Organization for Animal Health (Ozubek & Aktas, 2018; Seo et al., 2013; Seo et al., 2011; Short et al., 2012). EP is an endemic disease prevalent in the tropical and subtropical regions and in some temperate regions (Onyiche et al., 2019; Ozubek & Aktas, 2018; Wise et al., 2013). It has predominantly been reported in Asia, South and Central America, Africa, Southern Europe, and some parts of southern USA (Onyiche et al., 2019; Ozubek & Aktas, 2018; Wise et al., 2013). In Korea, EP by T. equi had been confirmed as 1.1% seroprevalence and 0.9% antigen prevalence from 224 horse samples from only three regions of whole country during 2007 - 2010 (Seo et al., 2013; Seo et al., 2011). After that, there was no surveillance of EP at national level, and it is needed to expand the monitoring the EP infectious status of all regions in Korea.
We examined antigens and antibodies from blood and serum of horses raised in the Republic of Korea (ROK) during 2016 - 2017, using polymerase chain reaction (PCR) for antigen detection and enzyme-linked immunosorbent assay (ELISA) for antibody detection. Subsequently, for antigen-positive samples, phylogenetic analysis was used to determine the genetic relationships with previous ones. In addition, the species of ticks distributed in the horse ranch and EP pathogens in the ticks were examined.
2.1 Sample collection
Whole blood and serum samples were collected by Korea Racing Authority
as national horse seroprevalence of major infectious diseases according
to the Animal Ethics regulations with the horse owners’ informed
consent. We surveyed the EP antigen and antibody in blood and serum
samples collected from 1,650 horses at 222 horse stables in 6
metropolitan cities and 9 provinces. The collected blood and serum
samples were stored at 4°C until use.