Serological evidence of anti-Toxoplasma gondii antibodies and haematological and serum biochemical alterations in wild rats and humans in Nigeria

Rats serve as carriers of Toxoplasma gondii, an obligate intracellular protozoan parasite that causes a global zoonotic disease referred to as toxoplasmosis, and thus play a very important role in the epidemiology of the disease. This study evaluated the occurrence of anti-Toxoplasma gondii antibodies, haematology and serum biochemistry in wild rats and humans in Nigeria where wild rats are consumed by humans as source of animal protein. Indirect enzyme-linked immunosorbent assay (iELISA) was used to detect anti-Toxoplasma gondii antibodies in serum of 33 wild rats (Zyzomys pedunculatus) caught in the villages and 20 consenting humans in the study area. Blood samples collected from the rats and humans were further subjected to haematological and biochemical evaluations. Out of the 33 rats sampled, three (9.09%) were positive for T. gondii antibodies, while three out of the 20 persons sampled (15%) were positive. Rats seropositive for T. gondii antibodies had significantly (p < 0.05) lower platelet count, higher granulocyte/lymphocyte ratio (GLR) and lymphocyte/monocyte ratio (LMR) than those seronegative for T. gondii antibodies. Mean corpuscular haemoglobin concentration (MCHC) was significantly (p < 0.05) lower while LMR was significantly (p < 0.05) higher in humans that were seropositive for T. gondii. It was concluded that anti-Toxoplasma gondii antibodies is moderately prevalent (9–15%) in rats and humans who consume rats as source of animal protein in the study area. High GLR in rats and high LMR in both rats and humans may be good pointers to toxoplasmosis.