Some children show a mixture of features, with some early delays and some later losses; and there is evidence of a continuous spectrum of behaviors, rather than, or in addition to, a black-and-white distinction, between autism with and without regression. There are several intermediate types of development, which do not neatly fit into either the traditional early onset or the regressive categories, including mixtures of early deficits, failures to progress, subtle diminishment, and obvious losses. Regression may occur in a variety of domains, including communication, social, cognitive, and self-help skills; however, the most common regression is loss of language. Some children lose social development instead of language; some lose both. Skill loss may be quite rapid, or may be slow and preceded by a lengthy period of no skill progression; the loss may be accompanied by reduced social play or increased irritability. The temporarily acquired skills typically amount to a few words of spoken language, and may include some rudimentary social perception.The prevalence of regression varies depending on the definition used. If regression is defined strictly to require loss of language, it is less common; if defined more broadly, to include cases where language is preserved but social interaction is diminished, it is more common. Though regressive autism is often thought to be a less common (compared with gradual course of autism onset described above), this is an area of ongoing debate; some evidence suggests that a pattern of regressive autism may be more common than previously thought.
A New York City firefighter developed eosinophilic pneumonia after inhalation of dust from the World Trade Center on September 11, 2001. Parasitic infections
Parasites cause eosinophilic pneumonia in three different ways. Parasites can either invade the lungs, live in the lungs as part of their life cycle, or be spread to the lungs by the bloodstream. Eosinophils then migrate to the lungs in order to fight the parasites, and cause eosinophilic pneumonia when they release their contents. Important parasites that invade the lungs include Paragonimus lung flukes and the tapeworms Echinococcus and Taenia solium. Important parasites which inhabit the lungs as part of their normal life cycle include the worms (helminths) Ascaris lumbricoides, Strongyloides stercoralis and the hookworms Ancylostoma duodenale and Necator americanus. When eosinophilic pneumonia is caused by helminths, it is often called "Löfflers syndrome". The final group of parasites cause eosinophilic pneumonia when their eggs are carried into the lungs by the bloodstream. This can include Trichinella spiralis, Strongyloides stercoralis, Ascaris lumbricoides, the hookworms, and the schistosomes. Acute and Chronic Eosinophilic Pneumonia
The causes for both acute and chronic eosinophilic pneumonia are unknown as of 2005. There is some suspicion that at least the acute form is the result of the bodys response to some unidentified environmental agent.