Comprehensive review of tropical endemic infections and demyelinating diseases of the central nervous system

Yara D Fragoso, Joseph B. Brooks, Eber C Correa, Carlos A Damasceno, Emerson L. Gasparetto, Marcus Vinicius M Goncalves, Alvaro R. Martins, Andre Muniz, Augusto C. Penalva Oliveira, Jean Pierre S. Peron, Gutemberg Augusto C. Santos, Henry Sato and Nise Alessandra C. Sousa

Background: Although more prevalent in higher latitudes, Multiple Sclerosis (MS) also affects individuals who live in tropical areas. Neuromyelitis Optica Spectrum Disorders (NMOSD), on the other hand, is more prevalent in tropical regions. For both demyelinating conditions, endemic tropical infections may be a serious complicating factor.

Methods: This was a comprehensive review carried out by a panel of specialists. The most prevalent endemic infections found between latitudes 23°27´ (Tropic of Cancer) and -23°27´ (Tropic of Capricorn) were , tuberculosis, Hansen’s disease, syphilis, leishmaniasis, leptospirosis, Human Immunodeficiency Virus (HIV), Human T-Lymphotropic Virus (HTLV), arboviruses and coronaviruses.

Results: Each of these infections was discussed in detail regarding the risk of affecting the clinical course of MS/NMOSD and the potential risks for individuals receiving immunomodulatory or immunosuppressive therapy.

Conclusion: Differential diagnoses between MS/NMOSD and the above-cited tropical infections are essential in endemic areas. Should the patient develop neurological symptoms during MS/NMOSD treatment, tropical infections need to form part of the differential diagnosis work-up when the patient lives in endemic areas. The risk of tropical infections in patients with MS/NMOSD needs to be taken into consideration regarding the choice of therapy. At present, most clinical trials, guidelines, and protocols have been developed and designed for high-latitude areas. Unfortunately, they do not consider potential infections that are prevalent in the tropical and equatorial zones.