Viral infections trigger multiple sclerosis relapses: a prospective seroepidemiological study.

A neurological surveillance was combined with prospective recording of upper respiratory and gastrointestinal infections and serological diagnosis of five common viral infections in 60 benign multiple sclerosis patients, with a mean follow-up of 31 months. During 4-week at risk (AR) periods encompassing common infections, a significant excess of MS relapses was found in the AR period, with a relative risk of 1.3. A seasonal variation of the MS relapse rate was found with a minimum in summer. There was a significant correlation between the number of AR relapses and the number of common infections per month explaining the periannual distribution of relapses. The non-AR relapses showed no seasonal variation. There was a significant correlation between adenovirus CF titre rises associated with upper respiratory infections and the occurrence of a major MS relapse in the AR period (n = 7), while influenza infections were not followed by a major MS relapse (n = 6). Linear homologies have been demonstrated between adenovirus and basic myelin protein. The epidemiological approach is essential to our understanding of systemic antigens triggering multiple sclerosis activity.

Delivery outcome in women who used drugs for migraine during pregnancy with special reference to sumatriptan.

OBJECTIVE: To evaluate delivery outcome in women who used drugs for migraine during pregnancy with special reference to sumatriptan. BACKGROUND: The safety of the use of drugs for migraine during pregnancy is not established. DESIGN AND METHODS: Using the Swedish Medical Birth Registry which contains information on drug use reported by women at the first antenatal visit, 912 infants (born in 905 deliveries) whose mothers had used drugs for migraine were identified, the majority of whom (n = 658) had used sumatriptan. RESULTS: These women differed from the general population of women who had delivered by being older and more often of first parity, but they had similar smoking habits. Slightly more often, the infants were preterm, and they had a birth weight less than 2500 g; neither of these effects were statistically significant. There seemed to be no difference between infants exposed to sumatriptan and those exposed to other drugs used for migraine. No increase in the rate of congenital malformations was seen. CONCLUSIONS: The data indicate that use of sumatriptan in early pregnancy does not result in a large increase in teratogenic risk, but do not rule out the possibility of a moderate increase in risk for a specific birth defect.

An epidemic-like cluster of motor neuron disease in a Swedish county during the period 1973-1984.

We have tried to find all cases of motor neuron disease (MND) with onset during the study period 1961-1990 in the county of Skaraborg, Sweden, and in this retrospective study we have identified 168 cases, 107 men and 61 women. Fifty percent of them were alive 2 years after onset. The number of MND cases in consecutive 5-year intervals during the study period was shown to be statistically significantly elevated for males in the period 1981-1985 (Knox test disjoint procedure, p = 0.02). During the period 1973-1984, 70 males had onset of MND, corresponding to an average annual incidence of 4 per 100,000 person-years. This epidemic-like cluster was compared to the MND morbidity in a neighbouring county and was shown to be statistically significantly elevated even when the p value was adjusted for multiple comparisons. Agricultural work was significantly more common among the cases compared to the rest of the population.