At least 10 Trichostrongylus species have been associated with human infections.[1] Infections occur via ingestion of infective larvae from contaminated vegetables or water. Since the use of herbivore manure as fertilizer is a common practice preceding infection, thorough cleaning and cooking of vegetables is required for prevention of infection. THE increase in organic farming and produce from mexico and south America is my guess. https://en.wikipedia.org/wiki/Trichostrongylus