You could use the Logistics and FREQ procedure in SAS since both are very useful for analyzing count data. PROC logistics uses the method of maximum likelihood.

Read how to here:

https://documentation.sas.com/doc/en/pgmsascdc/9.4_3.4/statug/statug_logistic_syntax01.htm

https://www.9to5sas.com/proc-freq-in-sas/

Lesion scoring system from zero to 3 acc.to lesion :

0 no lesion

1 mield ballooning in intestine, mield haemorrhage

2 moderate ballooning, moderate haemorrhage

3 sever ballooning, sever haemorrhage