Dermatophagoides sp. and IgE anti-D. pteronyssinus and D. farinae detection in a Venezuelan community at more than 2000 m above the sea level.
BACKGROUND
It has been reported that the concentration of Dermatophagoides sp. population, the main trigger of asthma in sensitized atopic subjects, is inversely related with altitude and probably directly with humidity and that this population are scarcely found over 1750 m above sea level.


OBJECTIVE
We studied the presence of Dermatophagoides sp. in a Venezuelan community between 2040 and 2600 m above sea level, and also the IgE response to D. pteronnyssinus and D. farinae in atopic subjects living on that region.


METHODS
The presence of Dermatophagoides sp. was determined by microscopic identification of mites in dust, obtained by brushing the mattresses surface in 93 randomly selected houses between 2040 and 2600 m above sea level. The indoor relative humidity was also measured. The specific IgE serum levels were studied in 65 subjects classified as asthmatics, allergic non-asthmatics and non-allergic.


RESULTS
A mean concentration of 188 mites/g of room dust was determined in 82.4% of houses with an indoor relative humidity ranging from 89% and 92% independently of altitude. The density of Dermatophagoides sp. was sufficiently high to sensitize the atopic subjects, IgE levels were 6.8 PRU mean value for asthmatic, against 0.38 PRU in non-atopic.


CONCLUSIONS
We conclude that: (a) Dermatophagoides sp. can be found up to 2600 m above sea level in a Venezuelan neotropical region where a high indoor relative humidity is characteristic of most dwellings; (b) sensitization by D. pteronyssinus and D. farinae were demonstrated in atopic subjects resident at that region.
Institute of Clinical Immunology, Faculty of Medicine, University of Los Andes, Mérida, Venezuela, South America.
A
A
Rangel
S
S
Salmen
J
J
Muñoz
F
F
García
M
M
Hernández
D000485:Allergens / Q000276:immunology*; D000531:Altitude; D000818:Animals; D039741:Antigens, Dermatophagoides; D001249:Asthma / Q000453:epidemiology / Q000276:immunology*; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis*; D008925:Mites / Q000276:immunology*; D015995:Prevalence; D011852:Radioallergosorbent Test; D011897:Random Allocation; D014687:Venezuela / Q000453:epidemiology
D000485:Allergens; D039741:Antigens, Dermatophagoides; D006023:Glycoproteins; D007073:Immunoglobulin E