Discussion

Wildlife are important sources and reservoirs for pathogens but little is known of the genetics of host-pathogen interactions. The badger (Meles meles) is well known for its role in the spread of bovine tuberculosis. Trypanosoma pestanai is the major trypanosome species in badgers. Toll-like receptors (TLRs) are key components of the innate immune system and studies have shown that variation in the TLR genes can affect susceptibility to infection in some pathogens. Little is known about variation in TLRs from badgers. TLR2 and TLR4 have been shown to be important in the recognition of trypanosome infections. This study aims to investigate the sequence diversity of TLR2 and TLR4 in badgers in relation to infection with T. pestanai. In a population of badgers studied (n=82), 35.4% (25.9% – 46.2%; 95%CI) were infected with T. pestanai using detection with nested ITS-PCR. The DNA sequence for exon 3 of TLR4 from badgers (n=59) showed no variation. The complete TLR2 sequence (n=61) showed three amino acid haplotype variants in regions that predicted changes in receptor recognition motifs (leucine-rich repeats). Ninety-five percent of badgers were homozygous for a predominant haplotype (H1). This surprising lack of diversity in badger TLR genes sequence meant that it was not possible to derive any meaningful association between TLR diversity and trypanosome infection.