i202 Grain weevil

Allergens within Insects

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  • Latin name: Sitophilus granarius
  • Family: Curculionidae
  • Source material: Whole insect bodies
Reported to be one of the causes of "Millworkers asthma".

Allergen Exposure

Sitophilus granarius is a common pest in stored grain. The allergy-causing components persist after processing (cleaning and milling) of the grain. The principal exposure is supposed to occur while bakers are exposed to the grain weevil allergens, together with other dust and flour allergen, but also during milling procedures.

Potential Cross-Reactivity

A German study has shown that another member of the genus S. oryzae, the rice weevil caused IgE-mediated allergy among people living in a former grain store. This study found several binding components, ranging from 30 to 70 kD and also observed cross-reactivity to the grain weevil (4, 5, 7).

Clinical Experience

Grain weevil has been reported to be one of the causes of "Millworkers asthma" (1, 2) and "Farmers lung" (3). Of 75 millworkers, 43 (57%) had a positive skin response to the weevil extract (2). In a study of 440 Swedish farmers some had a positive RAST to Sitophilus granarius (6). Danish bakers positive to S. granarius-extract were screened for IgE against S. granarius. CRIE analysis revealed 11 allergens of which 6 were potent and reacted to at least 50% of individual patient sera (7).
 
Review
Sitophilus granarius is a common pest in stored grain. The allergy-causing components persist after processing (cleaning and milling) of the grain. The principal exposure is supposed to occur while bakers are exposed to the grain weevil allergens, together with other dust and flour allergens, but also during milling procedures.

Grain weevil has been reported to be one of the causes of "Millworkers asthma" (1-2) and "Farmers lung" (3). Of 75 millworkers, 43 (57%) had a positive skin response to the weevil extract (2). In a study of 440 Swedish farmers some had a positive RAST to Sitophilus granarius (6). A German study has shown that another member of the genus S. oryzae the rice weevil caused IgE-mediated allergy among people living in a former grain store. This study found several binding components, ranging from 30 to 70 kD and also observed cross-reactivity to the grain weevil (4-5, 7). Danish bakers positive to S. granarius-extract were screened for IgE against S. granarius. CRIE analysis revealed 11 allergens of which 6 were potent and reacted to at least 50% of individual patient sera (7).

References:

    1. Frankland, AW; Lunn, JA. Asthma caused by the grain weevil. Brit J Industr Med 1965;22:157-9.
    2. Lunn, JA. Millworkers' Asthma: Allergenic Responses to the Grain Weevil (Sitophilus granarius). Brit J Industr Med 1966;23:149-58.
    3. von Ebner, H; Feldner, H; Kraft. Beitrag zur Kenntnis der „Farmerlunge". Wiener klinische Wochenschrift 1981;93:729-33.
    4. Gupta, S; Jain, S; Chaudhry, S; Agarwal. Role of insects as inhalant allergens in bronchial asthma with special reference to the clinical characteristics of patients. Clin Exp Allergy 1990;20:519-24.
    5. Kleine-Tebbe, J; Jeep, S; Josties, C; Meysel, U; O'Connor, A; Kunkel, G. IgE-mediated inhalant allergy in inhabitants of a building infested by the rice weevil (Sitophilus oryzae). Ann Allergy 1992;69:497-504.
    6. van Hage-Hamsten, M; Johansson, SGO. In vitro diagnosis of farmers' IgE-mediated allergy by Phadiatop® and three new multiallergen RAST analyses. Allergy 1993;48: 345-8.
    7. Herling, C; Svendsen, UG; Schou, C. Identification of important allergenic proteins in extracts of the granary weevil (Sitophilus granarius). Allergy 1995;50:441-6.

2000