Soto-Quiros M E, Ståhl A, Calderon O, Sanchez C, Hanson L A, Belin L
Department of Pediatrics, National Children's Hospital, University of Costa Rica, San José, Costa Rica.
Allergy. 1998 May;53(5):499-505. doi: 10.1111/j.1398-9995.1998.tb04087.x.
Previous studies of schoolchildren in Costa Rica have shown an asthma prevalence of 23% and a high level of sensitization, particularly to mite allergens. As a continuation of these studies, some 400 dust samples were collected from various places in Costa Rica, and parts of these were analyzed for specific mite and cockroach allergens, as well as for the number of mites and amount of guanine. Guanine was quantified by a diazo, as well as an HPLC method, which were found to be highly correlated. The concentrations of guanine by the diazo method, Der p 1, Der f 1, and the number of mites were higher in bed dust than in bedroom floor dust, and it was possible to quantify mite allergens and guanine in almost all bed-dust samples. The mean levels were 2-3 times higher than the proposed risk level for elicitation of symptoms in mite-sensitive asthmatics. Bed and bedroom floor dust contained more guanine and mite allergen in humid (> 2000 mm rain) than in drier places (P < 0.05), but the number of mites in bed and bedroom floor dust was higher in less humid places (P = 0.01). The guanine content in bedroom floor dust was higher in areas with a temperate climate than in areas with a warmer climate (P < 0.001, Bartlett's chi square [BCS]), as was the number of mites (P < 0.01, Kruskal-Wallis [KW], 0.04, BCS) and the Der p 1 concentration (P = 0.01, BCS; P = 0.02, KW). The Der f 1 concentration in bedroom floor dust was higher in a warmer than in a temperate climate (P < 0.001, BCS). More guanine and mites were found in urban than in rural bed dust (P = 0.03, KW). Dust samples from the metropolitan area (temperate climate) of Costa Rica contained higher levels of guanine (P < 0.01) and Der p 1 (P = 0.07) than the coastal areas, but very little Der f 1. In these samples, guanine and Der p 1 allergen were closely related, and 2 micrograms of the allergen was equivalent to 0.49 mg of guanine. Two-thirds of bed and floor samples collected on cotton filters contained Bla g 2 allergen at mean levels of 1.6 and 2.1 units/g dust, respectively. Cockroach allergen was, however, absent in all bed samples from the metropolitan area, but did occur in very high concentrations in the coastal bed dust samples collected with tighter polyester filters. In conclusion, the concentration of guanine and Der p 1 was very high in the bed dust of Costa Rican homes. Some factors, such as humidity, small houses for large families, and type of bedding, probably favored the heavy mite infestation, which is probably related to the widespread occurrence of bronchial asthma in this country.
此前对哥斯达黎加学童的研究表明，哮喘患病率为23%，致敏水平较高，尤其是对螨虫过敏原。作为这些研究的延续，从哥斯达黎加各地收集了约400份灰尘样本，并对其中部分样本进行分析，检测特定的螨虫和蟑螂过敏原，以及螨虫数量和鸟嘌呤含量。鸟嘌呤通过重氮法以及高效液相色谱法进行定量，发现二者高度相关。重氮法测得的鸟嘌呤浓度、Der p 1、Der f 1以及螨虫数量在床尘中高于卧室地板灰尘，并且几乎所有床尘样本中都能够对螨虫过敏原和鸟嘌呤进行定量。平均水平比诱发螨虫敏感型哮喘症状的建议风险水平高2至3倍。与较干燥地区相比，潮湿地区（年降雨量>2000毫米）的床和卧室地板灰尘中鸟嘌呤和螨虫过敏原含量更高（P<0.05），但湿度较小地区的床和卧室地板灰尘中螨虫数量更多（P = 0.01）。温带气候地区卧室地板灰尘中的鸟嘌呤含量高于气候较温暖地区（P<0.001，巴特利特卡方检验[BCS]），螨虫数量也是如此（P<0.01，克鲁斯卡尔 - 沃利斯检验[KW]，P = 0.04，BCS），Der p 1浓度亦是如此（P = 0.01，BCS；P = 0.02，KW）。卧室地板灰尘中Der f 1浓度在气候较温暖地区高于温带气候地区（P<0.001，BCS）。城市床尘中的鸟嘌呤和螨虫比农村床尘中更多（P = 0.03，KW）。哥斯达黎加大都市地区（温带气候）的灰尘样本中鸟嘌呤（P<0.01）和Der p 1（P = 0.07）含量高于沿海地区，但Der f 1含量很少。在这些样本中，鸟嘌呤和Der p 1过敏原密切相关，2微克过敏原相当于0.49毫克鸟嘌呤。在棉质滤纸上收集的三分之二的床和地板样本中含有Bla g 2过敏原，平均水平分别为1.6和2.1单位/克灰尘。然而，大都市地区所有床样本中均未检测到蟑螂过敏原，但在使用更紧密的聚酯滤纸收集的沿海床尘样本中蟑螂过敏原浓度很高。总之，哥斯达黎加家庭床尘中鸟嘌呤和Der p 1浓度非常高。一些因素，如湿度、大家庭居住的小房子以及床上用品类型，可能助长了螨虫的大量滋生，这可能与该国支气管哮喘的广泛发生有关。
