J Vet Sci.  2022 Sep;23(5):e75. 10.4142/jvs.22045.

Epidemiological investigation of equine hindlimb ataxia with Setaria digitata in South Korea

• Hwang H
• Ro Y
• Lee H
• Kim J
• Lee K
• Choi EJ
• Bae YC
• So B
• Kwon D
• Kim H
• Lee I

• KMID: 2533392
• DOI: http://doi.org/10.4142/jvs.22045

Abstract

Background
Since 2013, the number of requests for diagnosis for horses based on neurological symptoms has increased rapidly in South Korea. The affected horses have commonly exhibited symptoms of acute seasonal hindlimb ataxia. A previous study from 2015–2016 identified Setaria digitata as the causative agent.
Objectives
This study is an epidemiological investigation to find out risk factors related to the rapid increase in hindlimb ataxia of horses due to aberrant parasites in South Korea.
Methods
An epidemiological investigation was conducted on 155 cohabiting horses in 41 horse ranches where the disease occurred. The surrounding environment was investigated at the disease-causing horse ranches (n = 41) and 20, randomly selected, non-infected ranches.
Results
Hindlimb ataxia was confirmed in nine cohabiting horses; this was presumed to be caused by ectopic parasitism. Environments that mosquitoes inhabit, such as paddy fields within 2 km and less than 0.5 km from a river, had the greatest association with disease occurrence.
Conclusions
Most horse ranches in South Korea are situated in favorable environments for mosquitoes. Moreover, the number of mosquitoes in the country has increased since 2013 due to climate change. Additional research is required; however, these data show that it is necessary to establish guidelines for the use of anthelmintic agents based on local factors in South Korea and disinfection of the environment to prevent disease outbreaks.

Keyword

Epidemiology; ataxia; horses; mosquito vectors; setaria nematode