Rate of Co-infection with Malaria Parasites and Salmonella Typhi in Zaria, Kaduna State, Nigeria

Background: Typhoid and malaria co-infection is a major public health problem in many developing countries. Most of the co-infections treated are based on methods of diagnosis plagued with assumptions which possibly exaggerate the situation. Thus the aim of this work was to investigate the rate of co-infection with respect to the use of Widal test and blood culture methods for diagnosing typhoid fever in Zaria, Nigeria. Method: A total of 218 blood samples were collected from patients with a clinical suspicion of malaria and typhoid fever and examined for malaria parasites and S. typhi infection. Results: Sixty samples were positive for malaria parasites, 22 of which were positive for typhoid by the Widal test and only one by the culture method. The rate of co-infection was significantly high when typhoid was diagnosed by Widal (10.1%) than by blood culture method (0.5%). A correlation analysis showed no specific relationship between malaria parasite load and the level of Salmonella antibody titres in malaria patients (r = 0.05 and 0.08 for somatic and flagella antigens of S. typhi respectively). Conclusion: The incidence of typhoid and malaria co-infection will greatly reduce if the diagnosis of typhoid fever in malaria endemic areas such as Zaria is bases on blood culture