Misdiagnosis of Dengue Fever as Malaria and Typhoid Fever and Their Co-infection in Rural Areas of Southwest Nigeria

BACKGROUND: Misdiagnosis of dengue as malaria and typhoid fever can be a major source of public health concern in large areas of Nigeria, as dengue is not routinely screened for in health care settings and clinicians have to depend on empirical treatment which may compromise patients’ health. As studies have reported a high prevalence of the dengue virus in areas of Nigeria, dengue and malaria have similar symptoms, the same arthropod vector, and the same mode of transmission, coupled with differential diagnosis. Though typhoid fever differs from dengue and malaria by not having an arthropod vector and having a different mode of transmission, it shares a differential diagnosis with dengue and malaria, which makes misdiagnosis possible. The misdiagnosis of these three diseases has since become a major concern towards therapeutic administration because of their co-occurrence in many cases and the same location. METHODS: A total of 1074 samples were taken from rural health facilities in Southwest Nigeria and tested for malaria and typhoid fever. Those testing positive were tested for the DENV NS1 protein, DENV IgM, DENV IgG, and RT-PCR. RESULTS: Of the 1074 samples, 714 were positive for malaria, and 333 were positive for typhoid fever. From this, 315 (29.4%) were positive for DENV NS1. Fifty (6.7%) and 13 (3.9%) of the 714 malaria samples and 333 typhoid samples, respectively, had dengue fever co-infection. Co-infection of the three types of pathogens occurred in 5 (0.5%) of the samples. A total of 54 (5%) DENV cases were wrongly diagnosed as malaria, while 14 (1.3%) DENV cases were wrongly diagnosed as typhoid. CONCLUSION: Conclusively, there were a significant number of misdiagnosed cases of DENV as either malaria or typhoid, hence it is recommended to include DENV screening in routine hospital tests, especially in cases of malaria and typhoid negative by rapid diagnostic testing.