New York, Nov 11: The exotic ladybug species, Harmonia axyridis, could be a significant cause of respiratory allergy for residents of homes infested with these insects, clinicians from Kentucky warn.
This particular ladybug was first introduced from Asia in the 1970s and early 1980s in some eastern and southeastern states to control agricultural pests. Recent studies have reported that the H. axyridis population is gradually increasing across the US and replacing the native species of ladybugs.
"Entomologists now report a rapid increase in ladybug numbers, giving rise to increasing complaints of residential infestations," Dr. Kusum Sharma and colleagues from the University of Louisville note in their report in the Annals of Allergy, Asthma and Immunology.
Until 2005, there were just nine cases of ladybug (H. axyridis) hypersensitivity reported in the literature. However, in an anonymous survey of 99 residents of H. axyridis-infested Kentucky homes, Dr. Sharma''s team found the prevalence of self-reported ladybug hypersensitivity -- defined as worsening of allergy symptoms when ladybugs infested the home -- to be as high as 50%.
Nineteen percent of respondents reported allergy symptoms on direct contact with ladybugs and 31% reported the use of extra allergy medications during times of infestation.
"The correlation between worsening of allergy symptoms and time of infestation was significant for spring, fall, and winter infestations," Dr. Sharma said.
"We believe that this study will have significant clinical implications," the researcher continued. "Many cases of ladybug hypersensitivity go undiagnosed in the absence of proper recognition. We hope that patients with spring, fall and winter allergies will now be asked about ladybug infestation."
However, even when ladybug hypersensitivity is suspected, currently there is no commercially available ladybug extract to aid diagnosis. "Hopefully, we will soon see reagents for diagnostic testing on the market," Dr. Sharma said.
"This study shows that the prevalence of ladybug hypersensitivity is significant enough to warrant more research in this area," Dr. Sharma added.
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