A mong the most common enteric protozoan parasite that affects a variety of host animals is Cryptosporidium. Many Cryptosporidium spp. that have been linked to zoonotic illnesses across the globe include C. andersoni C.

Cryptosporidium is a ubiquitous protozoan parasite causing gastrointestinal disorders in various hosts worldwide. The current study was undertaken to study the biology of Cryptosporidium meleagridis and examine the anti-Cryptosporidial efficacy of curcumin in experimentally infected quails compared with that of paromomycin. This study carries out from September 2022 to January 2023 in Baghdad city, Iraq. Oocysts were isolated from naturally infected quails identified as Cryptosporidium meleagridis and used as a strain in experimental infection, about fifty birds were divided into five groups (G1: control negative group (con-), G2: control positive group (con+), G3: infected and treated with paromomycin, G4: infected and treated with curcumin and G5: uninfected and received curcumin). The oocyst shedding was recorded daily for 30 days. At 3,8,14, and 23 days post-infection (DPI), two quails from each group were killed humanely; ileum tissue samples were collected before and processed for histopathological evaluation. Improvement of tissue and the number of oocysts on the villi decreased after treatment. In comparison with G2, oocyst shedding was stopped at the end of the treatment period in both G3 and G4 without recurrence 10 days after drug withdrawal. The pre-patient periods (p.p) was 8-9 DPI. The maximum intensity was 11,000 oocysts per gram of feces. The first clinical sign was detected on 8 th DPI. Top of shedding occurred on 14 DPI, The patient period was 16 DPI. No clinical signs appeared on experimentally infected birds, (incubation period of 8 days). Histopathology examination of the infected ileum showed the development stages of C. meleagridis. There were significant differences between the curcumin (4.33 mg/kg/day) and paromomycin (100 mg/kg/day) treatments. Curcumin was able to treat the infection and needed father evaluation.