Serological and Molecular Detection of Rickettsia spp in Patients with Meningeal Syndrome in Northern Algeria.

Background: Rickettsioses are considered emerging or re-emerging hematophagous arthropod-borne zoonosis. In addition, Meningeal syndromes are among the most common reasons for consultation in infectious disease emergencies.

Objectives: Our study aimed to identify Rickettsia spp using IFA and qPCR for serological and molecular tests, respectively, in patients presenting with Meningeal Syndrome at the National Centre of Infectious Diseases El-HADI FLICI Hospital, Nicolle-Laveran department in Algiers.

Methods: We collected 55 whole blood and 55 sera from patients with meningeal syndrome of various ages and genders, with a mean age of 24.03 (ranging from 2 to 50 years old).

Results: The indirect immunofluorescence assay (IFA) for Rickettsia spp returned positive results in seven sera (7/55, 12.72%). We diagnosed four cases of Spotted Mediterranean Fever (MSF) caused by R. conorii, two cases of Murine Typhus caused by R. typhi, and one case of Flea-borne Spotted Fever caused by R. felis. Concerning the spinal tap, we reported that three patients were positive for R. conorii, where cerebrospinal fluid was opalescent, and there was a mixed cellular profile on cytology. These findings suggest a possible co-infection with R. conorii in patients with meningeal syndrome. Thus, the serological findings coupled with the Meningeal syndrome and the diverse clinical manifestations of both pathogens observed among these patients suggest a possible overlap in clinical expression.

Conclusion: These results highlight the importance of heightened awareness among infectious disease specialists, particularly when faced with confirmed cases of Meningeal Syndrome that may exhibit clinical similarities with Rickettsial diseases, especially in regions where hematophagous arthropod-borne zoonoses are prevalent.