Seasonal correlation of neuropsychiatric birth excesses to Ixodes ticks and Lyme borreliosis in America and Europe In America, the seasonal distribution of schizophrenic  and MS  birth excesses exactly mirrors the periodicity of Ixodes scapularis along the East Coast  and that of Ixodes pacificus along the West Coast . Curiously enough, in many studies conducted in the USA, the month of June is often the month with the lowest risk of developing schizophrenia (Jean-Paul Selten, personal communication, 2002). This schizophrenic birth deficit corresponds to the tick activity, which is at its lowest nine months earlier in September, being particularly striking, if both species Ixodes scapularis and Ixodes pacificus are taken together. If stochastic annual fluctuations are taken into consideration [43, 44], the spring (a) population of Ixodes ricinus  likewise mirrors the significant birth excess rates of schizophrenia , ALS  and MS  in Europe. The nine months' shift between sporadic schizophrenia on the one hand and ALS and MS on the other reflects the possible transplacental transmission of Borrelia burgdorferi  at the time of conception  and delivery .