REASSORTED ISA VIRUS

1 . A reassorted Infectious salmon anemia (ISA) virus comprising Genome segments 1-8 wherein at least one genome segment is from Genotype I and at least one genome segment is from genotype II, and wherein genome segment 6 is of Genotype II.

2 . The reassorted ISA virus of claim 1 , wherein at two least segments are of Genotype I.

3 . The reassorted ISA virus of claim 1 , wherein genome segment 5 is of Genotype I.

4 . The reassorted ISA virus of claim 1 , wherein genome segment 8 is of Genotype I.

5 . The reassorted ISA virus of claim 1 , wherein the genome segment of Genotype I is of Chilean origin.

6 . The reassorted ISA virus of claim 1 , wherein the segment of Genotype II is of Canadian origin.

7 . A vaccine composition comprising the reasserted ISA virus of claim 1 .

8 . A method of producing the reasserted ISA virus of claim 1 comprising the steps of:

(i) infecting a culture host with an ISA virus strain of genotype I and an ISA virus strain of genotype II;

(ii) culturing the culture host in order to produce reassorted ISAV virus; and

(iii) determining whether the reassorted ISAV virus has a segment 6 of genotype II present and at least one other segment of genotype I.

9 . The method of claim 8 , further comprising a step of (iv) purifying the virus obtained in step (iii).

10 . A method of culturing a reassorted ISA virus comprising

(i) infecting a culture host with the reassorted virus of claim 1 ; and

(ii) culturing the host from step (i) to produce further virus.

11 . The method of claim 10 , further comprising a step of (iii) purifying virus obtained in step (ii).

12 . The method of claim 8 , wherein the culture host is a suspension cell.

13 . The method of claim 8 , wherein the culture host is a CHSE-214 cell.

14 . The method of claim 8 , wherein the ISA virus is cultured in serum free medium.

15 . (canceled)

16 . The reassorted ISA virus of claim 1 , wherein segment 6 is of genotype II when the sequence of an amplicon obtained by forward primer of SEQ ID NO: 10 and reverse primer SEQ ID NO: 11 has at least 90% sequence identity with a segment 6 of NC_006499.

17 . The reassorted ISA virus of claim 1 , wherein the genotype of a segment is determined by obtaining an amplicon of a segment by the following primer pairs:

Segment

Forward primer

Reverse primer

1

SEQ ID NO: 16

SEQ ID NO: 17

2

SEQ ID NO: 18

SEQ ID NO: 19

3

SEQ ID NO: 20

SEQ ID NO: 21

4

SEQ ID NO: 22

SEQ ID NO: 23

4

SEQ ID NO: 24

SEQ ID NO: 25

5

SEQ ID NO: 26

SEQ ID NO: 27

6

SEQ ID NO: 28

SEQ ID NO: 29

7

SEQ ID NO: 30

SEQ ID NO: 31

8

SEQ ID NO: 32

SEQ ID NO: 33

and comparing the sequence of the amplicon with the sequence of corresponding segment of NC_006499;

wherein when the amplicon has less than 80% sequence identity with the corresponding segment of NC_006499 then the segment is a genotype I; and

wherein when the amplicon has at least 90% sequence identity with the corresponding segment of NC_006499 then the segment is a genotype II.

18 . The reassorted ISA virus of claim 17 , wherein when the amplicon has less than 85% sequence identity with the corresponding segment of NC_006499 then the segment is a genotype I; and

wherein when the amplicon has at least 90% sequence identity with the corresponding segment of NC_006499 then the segment is a genotype II.

19 . The method of claim 8 , wherein segment 6 is of genotype II when the sequence of an amplicon obtained by forward primer of SEQ ID NO: 10 and reverse primer SEQ ID NO: 11 has at least 90% sequence identity with a segment 6 of NC_006499.

20 . The method of claim 8 , wherein the genotype of a segment is determined by obtaining an amplicon of a segment by the following primer pairs:

Segment

Forward primer

Reverse primer

1

SEQ ID NO: 16

SEQ ID NO: 17

2

SEQ ID NO: 18

SEQ ID NO: 19

3

SEQ ID NO: 20

SEQ ID NO: 21

4

SEQ ID NO: 22

SEQ ID NO: 23

4

SEQ ID NO: 24

SEQ ID NO: 25

5

SEQ ID NO: 26

SEQ ID NO: 27

6

SEQ ID NO: 28

SEQ ID NO: 29

7

SEQ ID NO: 30

SEQ IDNO: 31

8

SEQ ID NO: 32

SEQ ID NO: 33

and comparing the sequence of the amplicon with the sequence of corresponding segment of NC_006499;

wherein when the amplicon has less than 80% sequence identity with the corresponding segment of NC_006499 then the segment is a genotype I; and

wherein when the amplicon has at least 90% sequence identity with the corresponding segment of NC_006499 then the segment is a genotype II.

21 . A method of vaccinating a fish against an ISA virus comprising administering to the fish the reassorted ISA virus of claim 1 , or a vaccine comprising said reassorted ISA virus.