1. Department of Nursing, College of Nursing, Pusan National University, Yangsan-si, Gyeongsangnam-do 626-870, Korea.
2. Department of Nursing, Youngsan University, Yangsan, Gyeongsangnam-do 626-790, Korea.
3. Department of Parasitology, School of Medicine, Pusan National University, Yangsan-si, Gyeongsangnam-do 626-870, Korea.
4. Pusan National University Hospital, Medical Research Institute, Busan 602-739, Korea.