Animal exposure over the life-course and risk of multiple sclerosis: A case-control study within two cohorts of US women

Childhood pet ownership and multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

Many studies have been conducted investigating a range of environmental factors which have been implicated in the pathogenesis of multiple sclerosis (MS). We collated available data about exposure to domestic animals before symptom onset in MS to perform a systematic review and meta-analysis.

METHODS

Medline, Embase and Cinahl were searched for relevant articles, based on pre-defined inclusion and exclusion criteria and reference lists were hand-searched. Data were extracted and critical analysis was conducted using the Newcastle-Ottawa criteria. Meta-analysis used random effects.

RESULTS

Study heterogeneity was high and study quality was variable. Random effects meta-analysis showed no associations with any pet ownership and development of MS.

CONCLUSION

It is not possible to draw definitive conclusions from this work. The studies included had a high level of heterogeneity. There are many variables involved in pet ownership and exposure and the nature of the way these have been studied makes the analysis challenging.

Increased frequency of canine distemper virus-specific antibodies in multiple sclerosis

BACKGROUND AND PURPOSE

Canine distemper virus (CDV) is a candidate agent in the etiology of multiple sclerosis (MS). Elevated anti-CDV levels were previously found in the sera from MS patients compared with controls. We now investigated whether there was an age-related association with the presence of antibodies specific to CDV-hemagglutinin (H) protein in MS.

METHODS

Sera from patients with MS, other neurological diseases, and inflammatory and/or autoimmune diseases, and healthy individuals were screened for anti-CDV in an ELISA using linear peptides of the CDV-H protein as antigen. Antibody levels to measles and varicella-zoster virus were measured and served as controls.

RESULTS

Analysis of the new cohort of MS patients and controls confirmed our initial finding of elevated anti-CDV-H levels in MS patients. An increase in measles but not varicella-zoster virus antibody levels was found in MS patients compared with healthy controls. Data from the new cohort of patients and controls were combined with data from the original study and analyzed with respect to age distribution of anti-CDV IgG. Mean CDV antibody levels were significantly elevated in each decade from 20 to 50 years of age in MS compared with healthy and disease controls. Antibody levels to measles virus were not consistently elevated during this age span. A striking relationship (p < .0001, odds ratio = 5.0) was observed between elevated anti-CDV-H levels and diagnosis of MS.

CONCLUSIONS

The finding that anti-CDV levels are elevated in MS patients of all ages provides substantial evidence of a strong association between elevated anti-CDV and MS.

Seroprevalence of anti-Toxocara antibody among multiple sclerosis patients: a case-control study

Although previous studies have shown an association between parasitic infections and multiple sclerosis, the possible role of Toxocara infection on the etiology of multiple sclerosis has been overlooked. The present study aimed to investigate the seroprevalence of anti-Toxocara IgG antibodies among patients with multiple sclerosis compared to healthy controls. Seventy patients with prior diagnosis of multiple sclerosis were selected as cases and 70 healthy matched individuals as controls. The presence of serum anti-Toxocara IgG antibody was investigated by ELISA technique. The Chi square test was used to test statistically significant differences for parametric data. A total of 140 serum samples were collected and analyzed. In the case and control groups, 20 (28.6%) and 8 (11.4%) participants had positive serum anti-Toxocara IgG antibodies, respectively, indicating a statistically significant difference (OR 3.1; 95% CI 1.26-7.63; p value = 0.02). The seroprevalence rate was also higher among individuals with a history of contact with dogs (OR 2.7; 95% CI 1.17-6.37; p value = 0.03).The results declare that a protective role of Toxocara canis against the development of multiple sclerosis is unlikely.