CD4 and parasitic infectious disease: fragile</i> at week 12 p.i., and were followed until week 20 p.i. Plasma viral loads, peripheral parasitemia, and peripheral and GI immune cell frequencies and function were assessed longitudinally.<h4>Results</h4>We observed significant CCR5+ CD4+ T cell decline in the periphery, colon, and duodenum following SIV infection.