Platelet Indices and Hemoglobin, Albumin, Lymphocyte, and Platelet (HALP) Score Alterations in Sheep with Molecularly Confirmed Theileria spp. Infection

The hemoglobin (Hb), albumin (ALB), lymphocyte (LYM), and platelet (PLT) components of the HALP score, a human-derived immune-nutritional index, are currently being investigated in the veterinary field. We aimed to evaluate and compare the HALP score and platelet indices (PI) in Theileria-infected and non-infected sheep.

One hundred sheep from different farms in Semnan Province were screened for the presence of Theileria between June and August 2023 using microscopy and molecular-based methods. Hematocrit (Hct), Hb, red blood cell (RBC), LYM, PLT, plateletcrit (PCT), mean platelet volume (MPV), platelet distribution width (PDW), and ALB were measured. The HALP score was calculated by multiplying Hb in ALB by LYM and dividing by PLT.

Microscopic and PCR analyses identified 21 and 27 positive samples for Theileria species, respectively. Results showed T. ovis in 52%, T. lestoquardi in 26%, T. annulata in 11%, and a co-infection of T. ovis and T. lestoquardi in 11% of the samples. The PLT and PCT showed significant differences in sheep infected with T. lestoquardi. A significant difference was also observed in PDW between sheep infected with T. ovis and T. lestoquardi compared to those infected with T. annulata. Statistical differences in the HALP score were noted for T. lestoquardi (P = 0.03), T. annulata (P = 0.01), and co-infections of T. ovis and T. lestoquardi (P = 0.05) versus T. ovis.

PLT indices (PI) and HALP scores can improve diagnostic processes, and future studies should use them alongside other methods for diagnosing Theileria species.