Physical Signs and Hematological and Biochemical Alterations in Salmonella-Plasmodium Sequentially Coinfected Albino Wistar Rats.

Abstract

Background: In endemic countries, people remain at risk of contracting both malaria and typhoid concurrently. Though experimental animal models are very reliable for understanding human diseases, the rat model for Plasmodium-Salmonella coinfection remains underresearched.

Objectives: The present study was performed to characterize the rat model of malaria-typhoid coinfection focusing on physical, hematological, and biochemical parameters.

Methods: Thirty-four Wistar rats were distributed into five groups including normal control, immunosuppressed, Salmonella-infected, Plasmodium-infected, and Salmonella-Plasmodium-coinfected. Physical signs, mobility, and the fecal appearance of animals were observed. Plasmodium load was monitored through microscopic Giemsa-staining thin blood smears. Concurrently, Salmonella load was evaluated after feces culture in Shigella-Salmonella agar medium based on the McFarland turbidity to determine the number of colony-forming units. Hematological and biochemical parameters were assessed using an automatic hematology analyzer and a spectrophotometer, respectively.

Results: All the infected animals exhibited at least one clinical sign including piloerection, eye depigmentation, or hyperthermia. Coinfected animals showed severe anemia, leukocytosis, and thrombocytosis compared with monoinfected animals. A significant (p < 0.001) drop in total blood proteins and cholesterol levels was observed in infected rats, with a remarkable decrease in Salmonella-Plasmodium-coinfected rats, whereas transaminase levels significantly (p < 0.001) increased in the same coinfected group.

Conclusion: This model provides many important features of Salmonella and Plasmodium sequential coinfection and therefore may be used as a tool to better understand, diagnose, and care for human malaria and/or typhoid pathogenesis.