Relative abundance for strains

[Rohit-Satyam]

Is your feature request related to a problem? Please describe.
I am using Kraken2 to detect coinfection of different dengue serotypes in 100s of sample. There are 4 serotypes of dengue and there is a possibility that a clinical sample might have two or more than two serotype. So I need abundances at S2 level

Describe the solution you'd like

Example this sample has co-infection of both Dengue 1 and dengue 2. I was wondering if there is a way to get relative abundance of Denv1 and Denv2 and other viruses at strain level

 69.33  3728    0       58425   482     S       3052464                   Orthoflavivirus denguei
 69.33  3728    0       58425   482     S1      12637                       Dengue virus
 40.75  2191    2191    29012   159     S2      11060                         dengue virus type 2
 28.58  1537    1537    28736   311     S2      11053                         dengue virus type 1

Describe alternatives you've considered
Currently I am using the following linux logic but this only enables me to fetch dengue related reads.

grep -A 3 'Dengue virus' Sample1260_kraken_report.txt | grep 'S2' | awk -F'\t' '{gsub(/^[[:space:]]+/, "", $8); print $3 ":" $8}'| tr '\n' ';'

Additional context
It would be nice to be able to calculate relative abundance of strain/serotype provided the species name like Orthoflavivirus denguei here.