There are many symptoms that are common to a wide variety of diseases, like fever, which can indicate an infection with any of a huge range of pathogens; an autoimmune disorder; or possibly even some cancers, for example. When a person has a persistent fever that cannot be explained, it is called fever of unknown origin (FUO), and it's estimated that globally, the causes of around half of all FUO cases are never determined. Scientists have now used many diagnostic tools to re-examine FUO cases in Sub-Saharan Africa to try to reveal more about the causes of these illnesses. The findings, which revealed a huge range of infections and illnesses, have been reported in The Journal of Infectious Diseases. They show how important advanced diagnostic tools can be to inform patients, practitioners, and policymakers.
In Sub-Saharan Africa, malaria is common enough that when a case is suspected, testing is not always done to confirm or rule out malaria. But other bacterial and viral infections may be causing these illnesses.
In this study, the researchers focused on 550 patients who were sickened in Guinea in 2014. These illnesses happened during a serious Ebola outbreak but these individuals tested negative for Ebolavirus. Serological and genetic tests indicated that more than one pathogen was present in 275 of these individuals. Many carried the parasite that causes malaria: Plasmodium, while pathogenic bacteria including Salmonella and Klebsiella were identified in about 20 percent of these patients.
Other viral pathogens were also found in about six percent of patients, including Yellow fever, Lassa and Ebolavirus. There were also Orungo virus infections. Little is known about this pathogen, and it was only detected with RT-PCR, a sensitive method that can amplify specific bits of DNA, such as genetic material from the Orungo virus. There are no other reliable assays for this virus right now.
Other assays revealed even more infections, including Dengue, West Nile and Crimean-Congo hemorrhagic fever viruses. These viruses were identified with immunofluorescence, which uses antibodies to reveal the presence of specific molecules, and RT-PCR was not sufficient to identify these pathogens.
The research shows how difficult it can be to identify some illnesses without many advanced molecular tools. Patients are left at a serious disadvantage when their illness cannot be quickly or correctly diagnosed, since that the right diagnosis is usually the only way top provide the proper treatment.
"Our results show that regionally adapted treatment regimens should be discussed, that quality control in the context of outbreaks needs to be strengthened, and that knowledge of the pathogen spectrum can guide targeted strengthening of regional laboratories and translational research in the sense of point-of-care tests," noted senior study author Professor Jan Felix Drexler of the German Center for Infection Research (DZIF) at Charité—Universitätsmedizin Berlin.
Sources: Deutsches Zentrum für Infektionsforschung, The Journal of Infectious Diseases
