Can Gastroenteritis Cause Variation In Lymphocytes Count?

Hi,My son is 7 years old. He is vomiting, has diarrhea and fever for last 3 days. In blood test we made in ER the absolute lymphocytes count was 0.65. The final diagnose was gastroenteritis. We just worried as we didn t find correlation between diagnose and lymphocytes count value. Is it expected to have such result caused by gastroenteritis?