Prevalence and molecular identification of Leucocytozoon spp. in fighting cocks (Gallus gallus) in Thailand

Leucocytozoon has been globally described as avian hosts, and it significantly affects many avian taxa including the fighting cock. The clinical signs of leucocytozoonosis range from asymptomatic to high morbidity leading to increase mortality rates. Interestingly, there are insufficient epidemiological studies of this blood parasite or the molecular identification of infections within the vertebrate host. In this study, 250 blood samples were collected from fighting cocks at 9 districts in Maha Sarakham Province, Thailand. Leucocytozoon infections were screened by blood examination and nested PCR followed by sequence analysis of mitochondrial cytochrome b gene was used to identify Leucocytozoon species. Twenty-two out of 250 (8.8%) samples had confirmed Leucocytozoon infections based on microscopic examination whereas with nested-PCR, 52 samples tested positive. Of these 52, 51 were successfully sequenced among which, one was Plasmodium juxtanucleare, 45 were Leucocytozoon sp. (18%) and 5 were L. schoutedeni (2%). This study is the first report to demonstrate the molecular prevalence of leucocytozoonosis in fighting cock in Thailand. This study indicated that leucocytozoonosis is widespread in fighting cock although the frequency was not determined and needs further study.