类鼻疽又被称为“越南定时”，这种疾病在越南战争后引起了人们的极大关注。随着美军直升机在这个亚热带国家频繁起降，螺旋桨激起的尘埃将士兵和飞行员暴露在曾隐藏在土壤中的病原体面前。

类鼻疽的症状与许多疾病很类似，包括皮肤感染和肺部化脓。但有一些患者却会演变出严重的败血症，在一些地区，这种疾病的死亡率甚至高达40%。

为了找到其中的原因，英国谢菲尔德大学的分子生物学家Stuart Wilson和同事对类鼻疽杆菌的一种蛋白质BPSL1549进行了研究，后者与在大肠杆菌中常见的一种酶很类似。这种大肠杆菌蛋白质是一种细胞毒素。

为了搞清这种酶的作用，研究人员分别向两组小鼠体内注射了携带BPSL1549及没有携带这种蛋白质的类鼻疽杆菌。结果显示，前者杀死的啮齿动物数量是后者的100倍。Wilson说，可见，虽然这种微生物也会产生其他一些毒素，但BPSL1549无疑是其中*毒的。

研究人员在*新出版的美国《科学》杂志上报告了这一研究成果。

类鼻疽是由类鼻疽杆菌所致的地方性传染病，流行于东南亚和澳大利亚北部等热带地区。人主要是通过接触含有致病菌的水和土壤，经破损的皮肤而受感染 。该病潜伏期一般为3～5天，但也有感染后数月、数年，甚至20年发病的情况。此类病例常因外伤或其他疾病而诱发。临床表现复杂，有急性败血症者常伴多处化脓性损害，慢性者类似空洞型肺结核表现。病情一般较为严重，如不及时治疗，病死率甚高。

Erythrocyte invasion by Plasmodium falciparum is central to the pathogenesis of malaria. Invasion requires a series of extracellular recognition events between erythrocyte receptors ａnd ligands on the merozoite, the invasive form of the parasite. None of the few known receptor–ligand interactions involved are required in all parasite strains, indicating that the parasite is able to access multiple redundant invasion pathways. Here, we show that we have identified a receptor–ligand pair that is essential for erythrocyte invasion in all tested P. falciparum strains. By systematically screening a library of erythrocyte proteins, we have found that the Ok blood group antigen, basigin, is a receptor for PfRh5, a parasite ligand that is essential for blood stage growth. Erythrocyte invasion was potently inhibited by soluble basigin or by basigin knockdown, ａnd invasion could be completely blocked using low concentrations of anti-basigin antibodies; importantly, these effects were observed across all laboratory-adapted ａnd field strains tested. Furthermore, Ok^a− erythrocytes, which express a basigin variant that has a weaker binding affinity for PfRh5, had reduced invasion efficiencies. Our discovery of a cross-strain dependency on a single extracellular receptor–ligand pair for erythrocyte invasion by P. falciparum provides a focus for new anti-malarial therapies