Based on these variables (drinking water, raising livestock, HIV infection route, CD4+ T cell count, HIV virus load, gender and washing hand after defecation) were involved in the multivariate model, further analysis showed that only four factors were association with Blastocystis infection as follows: raising animal, drinking water, CD4+ T cell count and HIV virus load (Table 2). Here, CD4 is linked to Blastocystis infectious disease.