Molecular Characterization, Genotypes and Phenotypes of Cysticercus Tenuicollis (Taenia Hydatigena) From Naturally Infected Goats Slaughtered in Al-Muthana and Al-Diwaniyah Province

Abstract

      The current study included the phenotypic and genetic characteristics of Cysticercus.tenuicollis, the thin-necked tapeworm in goats. 3145 samples of goats from animals slaughtered in slaughterhouses were examined for the period from April 2022 to July 2022 in the Diwaniyah and Muthanna governorates. The results of the study showed that the infection rate in Goats: The infected animals amounted to 672 heads, at a rate of 21.36%. The current study aimed to study the morphological characteristics of the sacs, heads, and snout spines of larvae isolated from goats, molecular diagnosis, and identification of genetic mutations of the parasite at the level of DNA and amino acids. In this study, the phenotypic characteristics of The larval stage of C. tenuicollis were determined in terms of the number of sacs and their sizes, and the number of galls and their lengths. It was found that the highest percentage of cysts in goats was 1-2, at a rate of 90.92%. their sizes ranged between 1-12 cm. the liver cysts were 1-2 cm in size, while in the peritoneal cavity, it was 1-12 cm. The number of large and small hooks surrounding the rostellum was calculated, and The total number was 30 hook,which were equal in number and an average of 15 for each. The average length of the large hooks was 192.48±3.04 microns, and the small hooks were 121.25±2.56 microns.

       The results of the molecular study of the Polymerase Chain Reaction (PCR) technique using three mitochondrial genes: Cytochrome c oxidase subunit 1 gene (COX1), Mitochondrial cytochrome b gene (Cytb) and NADH dehydrogenase subunit 4 gene (Nd4) showed that the amplification results of DNA extracted from the scolex and germinal layer of C. tenuicollis cyst samples were positive at the molecular sizes of mitochondrial genes (444, 568, 680 bp,  in all samples respectively).

     The results of the genetic sequencing of the larval stage of C. tenuicollis showed that all local samples studied were identical to the global isolates, Turkey (MK851045), Iran (KR337823.1) and Egypt (OQ317833 which registered in the National Center for Biotechnology Information (NCBI), and a comparison of the alignment of the sequences of the nitrogenous bases showed For local isolates the match rate of 100%, and as for the Saudi isolates (MZ277312), the match rate was 99.74%.The genetic sequencing of the mt-Cytb and mt-Nad4gene genes, all isolates were identical to the Chinese isolates, and the percentage of identity ranged between 97.62-99.27% ​​and 98.58-98.90%, respectively.Nucleotides bases sequence were converted to the amino acid sequence using the EXpasy software program. The results of the sequence showed the amino acids of the parasite strains in local  samples,similar to global isolates which were recorded in the International Gen Bank, such as the Iranian isolate (AFL69973.1) was 96.15%, and the Turkish isolate (AFA53641.1) had a match rate of 97.85%. As for the Cytb gene,Mache with Chinese isolate (ACN72662.1)the similarity ranged between 90.21-96.36% , and the NAD4 gene ranged between 89.67-90.78% with the Chinese isolates (UXP71673.1 and AGJ83395.1), respectively. The results of the current study indicated the presence of mutations among the local isolates at the acid sequence level. amino acids, as 14 basic mutations were found in the COX1 gene, 13 basic mutations in the Cytb gene, which included the presence of a deletion mutation, that is, deletion of a complete amino acid, and 13 basic mutations in the Nad4 gene, which also included the presence of a deletion mutation.