Hello Thanks for query Your son s problem is really worry sum. Hb 1.8 is very low for the baby. There are so many condition in which there red cells can be deficient in infancy like pure red cell aplasia. DBF syndrome, P R syndrome and treatment and outcome depends on the type of disease. If bone marrow is showing less erythrocytes most likely is pure red cell aplasia, but its very difficult to say without going through the investigations and clinical evaluation properly. So I would suggest you to consult a pediatrician or better a hematologist for proper management of your son. Its very unlikely that Tolerva has any relation with this because till date there is not even a single study suggests this. I hope this answers your query With regards