Co-infection and the density of Spiroplasma, Trypanosoma, and Wigglesworthia

The density of Spiroplasma, Trypanosoma, and Wigglesworthia was evaluated using relative qPCR based on the single (Sp + / T —; Sp — / T +) and double co-infection (Sp + / T +) status. As expected, the results showed that flies infected with Spiroplasma (Sp + / T — and Sp + / T +) had a significantly higher density of Spiroplasma compared to those not infected (Sp — / T +), which indicated that flies classified as uninfected by conventional PCR showed lower infection rates with qPCR. However, there was no significant difference in the density of Spiroplasma between flies infected with Spiroplasma and not infected with Trypanosoma (Sp + / T —) and those infected with both (Sp + / T +) (Fig. 5A). Furthermore, flies with double co-infection (Sp + / T +) had a significantly higher density of trypanosomes than those with single co-infection (Sp + / T — and Sp — / T +) (Fig. 5B). However, no significant difference was found in the density of Wigglesworthia in the three categories of co-infection (Fig. 5C).