Table 3. List of primers and sequences used in this study. Primer
Virus
Sense
Gene
Primer Seq. (5'-3')
pNK61
Universal
Negative
P2B
GACATGTCCTCCTGCATCTG
pNK72
Universal
Negative
P2A
GAAGGGCCCAGGGTTGGACTC
pARS4
Type O
Positive
P1C
ACCAACCTCCTTGATGTGGCT
Type A
Positive
P1C
TGGTTGGAGGAACTACACCGA
1C562
Results and Discussion The nucleotide sequences of type O and A viruses used in this study and previously sequenced viruses were plotted as dendograms and shown in Figures 1 and 2. Viruses that have a difference of about 5% or less in nucleotide sequence were considered as closely related ( Samuel et al., 1988). All type A viruses sequenced in this study were closely related to each other and A/Iran/96 virus group. A/Iran/96 was first detected in Turkey at the end of 1997 (A/TUR/12/97). The nucleotide difference between these viruses and other type A viruses isolated previously from Turkey was over 18% (Aktas, 1998). The results of this study showed that type A viruses isolated from Turkey between 2000 and 2002 were belonging to A/Iran/96 group. The close genetic relationship between field isolates and the Turkish vaccine strain (same as A/TUR/40/98) and r values detected by antigenic characterisation ELISA, shown in brackets in Figure 1 and Table 3 ), confirmed that the current type A vaccine strain was suitable for Turkey. The sequencing results of type O viruses isolated from Turkey between 2000 and 2002 showed that there were three different genetic sublineages circulating in Turkey during this period. Similar result was found in a previous study (Aktas, 1998). Although these viruses were genetically different from each other, all of these type O FMD viruses could be considered as belonging to a single genotype since nucleotide differences between these viruses were less than 15% (Samuel et al., 1997). On the other hand antigenic study showed that these viruses were closely related to the vaccine strain, O Manisa 1969 (Table 3).
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