Pulmonary eosinophilia is seen in the following parasitic infections except –
Pulmonary eosinophilia typically occurs when parasites migrate through the lungs. For example, in strongyloidiasis (Strongyloides stercoralis), the larvae migrate through the lungs, causing Löffler's syndrome. Similarly, Ascaris lumbricoides larvae also migrate through the lungs during their development. Paragonimus westermani causes pulmonary symptoms but more related to adult flukes, not larvae. Hookworms (like Ancylostoma duodenale) have larvae that migrate through the lungs, leading to eosinophilia.
Wait, the exception here would be a parasite that doesn't involve larval migration through the lungs. Paragonimus westermani causes pulmonary symptoms but the adult flukes are in the lungs, not the larvae. So maybe Paragonimus is the exception? Let me confirm. Pulmonary eosinophilia is usually due to larval migration. Paragonimus would cause lung damage from adults, not larvae. So if the options include Paragonimus, that's the correct answer here.
But wait, the options aren't listed, so I need to think of common parasites. Let me list some: Strongyloides, Ascaris, Hookworms, Toxocara, Paragonimus. Paragonimus is a lung fluke, and while it does cause pulmonary symptoms, the eosinophilia is more from the adult fluke's presence rather than larval migration. So Paragonimus might not present with pulmonary eosinophilia in the same way as the others. Therefore, the exception would be Paragonimus westermani. So the correct answer would be Paragonimus if it's an option. The question is structured to have that as the exception. So the explanation should highlight that the other parasites have larval migration causing pulmonary symptoms and eosinophilia, while Paragonimus causes symptoms from adult flukes in the lungs, not larvae.
**Core Concept** Pulmonary eosinophilia occurs when parasitic larvae migrate through the lungs, triggering an eosinophilic inflammatory response. This is classic in helminthic infections with larval pulmonary phase, such as Strongyloides, Ascaris, and hookworms. Paragonimus, however, primarily involves adult flukes in the lungs.
**Why the Correct Answer is Right** *Paragonimus westermani* causes pulmonary symptoms via adult flukes in lung parenchyma, not larval migration. Pulmonary eosinophilia is typically driven by larval antigen release during migration (e.g., Strongyloides stercoralis or Ancylostoma duodenale), activating Th2-mediated eosinophilia. Paragonimus induces granulomatous inflammation rather than eosinophilia.
**Why Each Wrong Option is Incorrect**
**Option A:** *Strongyloides stercoralis*—Larval migration through alveoli causes Löffler’s syndrome with eosinophilia.
**Option B:** *Ascaris lumbricoides*—Larvae traverse lungs during development, triggering eosinophilic infiltration.
**Option C:** *Ancylostoma duodenale*—Hook