Molecular identification of helminth parasites of the Heterakidae and Ascarididae families of free-ranging chickens from selected rural communities of KwaZulu-Natal province of South Africa

Abstract

Free-range chickens are predisposed to diverse parasitic infections during scavenging. Accurate identification of these parasites using morphological characters has been a challenge. Therefore, this study aimed to identify nematodes from the Heterakidae and Ascarididae family infecting free-ranging chickens from KwaZulu-Natal province of South Africa using a combination of morphological and molecular techniques. Forty-two free-ranging adult indigenous chickens were purchased from randomly selected households in Shongweni (n=12), Umzinto (n=10), Gingindlovu (n=10) and Ozwathini (n=10) rural villages and examined for nematodes of the Heterakidae and Ascarididae family. Collected specimen were identified morphologically and confirmed using mitochondrial and nuclear ribosomal markers. Results showed that Ascaridia galli was common, occurring at all sampling locations with an overall prevalence of 58.3%, while Heterakis gallinarum and H. beramporia occurred in three locations. Ascaridia galli had high prevalence in Shongweni (58.3%), followed by Gingindlovu (40%), Ozwathini (20%) and Umzinto (10%). Heterakis gallinarum infection was prevalent in three locations, with an overall prevalence of 90% in Gingindlovu, 80% in Ozwathini and 58.3 % in Shongweni. Heterakis gallinarum and H. beramporia were not recorded in Umzinto. Heterakis beramporia was recorded in low prevalence in Gingindlovu (20%), Ozwathini (10%) and Shongweni (8.3%) villages. Mixed infections of A. galli and H. gallinarum were recorded in Gingindlovu, Ozwathini and Shongweni, and H. gallinarum and H. beramporia in Gingindlovu. Molecular analysis confirmed identification of A. galli, and further showed close relationship with the GenBank-derived South African isolates. Haplotype network further confirmed their ancestral history, where all South African A. galli isolates formed five novel haplotypes corresponding with the structure of the phylogenetic tree. Similar structure was observed with Heterakis isolates, where analysis of the cox1 gene showed that H. gallinarum formed a well-supported monophyletic clade with other Heterakis species. The ITS marker identified three specimens from Gingindlovu, Ozwathini and Shongweni as H. beramporia, which formed strongly supported sister clade to H. indica and this is the first report confirming the occurrence of H. beramporia in South Africa.

Keywords: Ascarididae; Heterakidae; South Africa; free-range chickens; gastrointestinal helminth.