Genotypization of selected candidate markers for resistance against lentiviral infections of small ruminants

Small Ruminant Lentiviruses (SRLV) known as maedi-visna in sheep, and viral arthritis and encephalitis in goats are widespread worldwide and cause significant economic losses. Lentiviral diseases have been included in the current Animal Health Control and Vaccination Guidelines for Breeding Controls. Control programs are generally based on serological screening and subsequently serologically positive animals are removed from breeding. In the literature review I write about important lentiviruses, including those that have not been analyzed. The aim of this work was to screen for the occurrence of lentiviral infections in small ruminants in the Czech Republic and the genotyping of selected candidate markers and finding the genotype related to the possibility of gene resistance. In total, over 3200 blood samples were collected from sheep and goats from breeders all over the Czech Republic. Genotyping was carried out in herds where serologically positive animals were detected. Amplification of the DNA sequence of interest was performed by PCR (Polymerase Chain Reaction) analysis, followed by genotyping by sequence analysis, and the results were statistically evaluated. In my work, I came to the conclusion that in the Czech Republic the occurrence of 2 out of 5 possible SRLV genotypes (genotype A and B) and distribution of different subtypes in sheep and goats has been detected so far. The greatest differences were in the sequence of genotype A, where one group of isolates showed the possibility of classification into a completely new subtype. In sheep, all three genotypes of the TMEM154 gene were identified. The incidence of serologically positive was statistically significantly higher in animals with a risk genotype. Because of the possible mutation of the virus and the emergence of a new subtype of genotype A, the virus is more likely to adapt to attack and infect individuals with a more resistant genotype. Only one genotype has been demonstrated in goats, so most likely there is no marker associated with resistance to SRLV infections