In most of the cases, the only organism responsible for all allergic symptoms and signs of ABPA is:

Ans. C. Aspergillus fumigatus. (Ref. H-17th/pg. 1610; Table 249-3).In most of the cases, the only organism responsible for all allergic symptoms and signs of ABPA is Aspergillus fumigatus.Harrison's 17th/pg. 1610..........."When an eosinophilic pneumonia is associated with bronchial asthma, it is important to determine if the patient has atopic asthma and has wheal-and-flare skin reactivity to Aspergillus or other relevant fungal antigens. If so, other criteria should be sought for the diagnosis of allergic bronchopulmonary aspergillosis (ABPA) or other, rarer examples of allergic bronchopulmonary mycosis such as those caused by Penicillium, Candida, Curvularia, or Helminthosporium spp. A. fumigatus is the most common cause of ABPA."Allergic Bronchopulmonary Aspergillosis (ABPA)Diagnostic Features of ABPAMain Diagnostic Criteria:# Bronchial asthma# Pulmonary infiltrates# Peripheral eosinophilia (>1000/L)# Immediate wheal-and-flare response to Aspergillus fumigatus# Serum precipitins to A. fumigatus# Elevated serum IgE# Central bronchiectasisOther Diagnostic Features:# History of brownish plugs in sputum# Culture of A. fumigatus from sputum# Elevated IgE (and IgG) class antibodies specific for A. fumigatusAdditional Educational points:# The chest roentgenogram in ABPA may show transient, recurrent infiltrates or may suggest the presence of proximal bronchiectasis. High-resolution chest CT is a sensitive, noninvasive technique for the recognition of proximal bronchiectasis.# The bronchial asthma of ABPA likely involves an IgE-mediated hypersensitivity, whereas the bronchiectasis associated with this disorder is thought to result from a deposition of immune complexes in proximal airways. Adequate Rx usually requires the long-term use of systemic glucocorticoids.