Frequency of Blood-tissue Parasitic Infections in Patients with Multiple Sclerosis, as Compared to their Family Members

BACKGROUND: Multiple Sclerosis (MS) is a chronic demyelinating disease of the central nervous system which has been identifies more prevalent in economically developed countries than in the developing countries. Low prevalence of parasitic infections (which can activate immune response and prevent or modulate damage to host antigens) in these areas is among the possible responsible factors for such a difference. In this study we aimed to compare frequency of blood-tissue parasitic infections in patients with MS, as compared to their healthy family members. METHODS: This study was conducted on 50 relapsing remitting MS patients and 50 family members attending MS clinic at Alzahra Hospital. IgM and IgG anti-Toxoplasma gondii were measured. Given the high prevalence of cutaneous leishmaniasis in Isfahan, all the participants were also examined for protozoan leishmania microscopically. Furthermore malaria parasite was investigated. RESULTS: Eighteen patients and 24 healthy family members had positive test in IgG Toxoplasma gondii(P = 0.09). In both groups, there was no positive IgM Toxoplasma gondii. In investigating leishmania, only 3 participants in the case group and 2 in the control tested positive (P = 0.25). No case of malaria was found among the participants. CONCLUSION: Our results showed a mismatch with hygiene hypotheses examined. However, considering that the prevalence of parasites varies with time, and depends on numerous epidemiological factors; these results do not discredit the theory investigated.