Abstract

Background

Haemophilus influenzae bacteria can cause asymptomatic carriage and invasive disease. Haemophilus influenzae serotype a (Hia) is an emerging cause of invasive disease in Alaska, with greatest burden occurring among rural Alaska Native (AN) children. The first case of invasive Hia (iHia) in Alaska was reported in 2002; however, it is unclear how long the pathogen has been in Alaska.

Methods

We quantified immunoglobulin G antibodies against Hia (anti-Hia) in 839 banked serum samples from Alaska residents, comparing antibody concentrations in samples drawn in the decades before (1980s and 1990s) and after (2000s) the emergence of iHia. We also assessed serum antibody concentration by age group, region of residence, and race.

Results

The anti-Hia was >0.1 µg/mL in 88.1% (348 of 395) and 91.0% (404 of 444) of samples from the decades prior and after the emergence of Hia, respectively (P = .17). No significant differences in antibody levels were detected between people from rural and urban regions (1.55 vs 2.08 µg/mL, P = .91 for age ≥5) or between AN and non-AN people (2.50 vs 2.60 µg/mL, P = .26).

Conclusions

Our results are consistent with widespread Hia exposure in Alaska predating the first iHia case. No difference in Hia antibody prevalence was detected between populations with differing levels of invasive disease.

中文翻译：

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侵袭性感染出现前后阿拉斯加流感嗜血杆菌血清型 a 抗体的存在

摘要

背景

流感嗜血杆菌可引起无症状携带和侵袭性疾病。流感嗜血杆菌血清型 a (Hia) 是阿拉斯加侵袭性疾病的新原因，在阿拉斯加原住民 (AN) 农村儿童中负担最大。2002年在阿拉斯加报告了第一例侵入性Hia（iHia）病例；然而，目前尚不清楚病原体在阿拉斯加存在了多久。

方法

我们在来自阿拉斯加居民的 839 份银行血清样本中量化了针对 Hia（抗 Hia）的免疫球蛋白 G 抗体，比较了 iHia 出现之前（1980 年代和 1990 年代）和之后（2000 年代）几十年抽取的样本中的抗体浓度。我们还按年龄组、居住地区和种族评估了血清抗体浓度。

结果

在 Hia 出现之前和之后的几十年中，分别有 88.1%（395 个中的 348 个）和 91.0%（444 个中的 404 个）的抗 Hia > 0.1 µg/mL ( P  = .17)。在农村和城市地区的人群（1.55 对 2.08 µg/mL， 年龄≥5 岁，P = .91）或 AN 和非 AN 人群（2.50 对 2.60 µg/mL，P  = .26）。

结论

我们的结果与阿拉斯加在第一例 iHia 病例之前广泛暴露于 Hia 的情况一致。在具有不同侵袭性疾病水平的人群之间没有检测到 Hia 抗体流行率的差异。