Hi...I went through the history points you have provided - THIS IS NOT A VIRAL INFECTION.
I feel that your baby is having cow's milk
protein allergy (CMPA). Unusually babies grow out of this sort of allergy by 1 year of age.
My suggestions for you -
1. Mother should go off cow's milk protein completely. This means that you should avoid consumption of anything and everything related to cow's milk - like - milk/ curds/ ghee/ butter milk/ chocolates/ biscuits/ ice creams etc. Even while buying commercial food products, you need to see the ingredients and if they contain milk - do not consume them.
2. Feed you baby only exclusive breast feeds till 6 months of age and then start rice based feeds.
3. If this is followed scrupulously - the baby will stop having
diarrhoea in another 3-4 days and then start gaining weight too.
4. If you feel your feeds alone are inadequate for the baby, then Zerolac is the only option.
I request you to keep me posted about the recovery of the baby and follow of the case.
I wish your kid a speedy recovery. If you need any future medical consultation and suggestions, I will be glad to help. You can approach me at the following link. Please find the link below -
www.healthcaremagic.com/doctors/dr-sumanth-amperayani/67696
Regards – Dr. Sumanth