Surveys on new human malaria in South East Asia

对泰国、印度尼西亚、缅甸和中国四国的疟疾疫情进行了现场调查，采用了吖啶橙(AO)染色方法。将诊断结果与微量平板杂交法(MPH)和套式聚合酶链式反应方法进行比较。在泰国，共采集了548份样本，通过公共卫生和/或套式聚合酶链式反应方法确认了许多通过AO方法诊断的疟疾和卵形疟原虫感染。他们的患病率分别达到20%和2.2%左右。此外，三个卵形肺孢子虫感染的样本为AO阳性，但MPH阴性。对目标序列的分析表明，这些分离株与越南发现的分离株具有相同的突变类型(两个核苷酸缺失和一个核苷酸替换)。另一方面，恶性疟原虫分离株在18S rRNA基因的靶区存在点突变。在中国，也用这三种方法在四川省发现了许多疟原虫感染。套式聚合酶链式反应扩增产物在探针区有一长串缺失，提示这可能是疟原虫新的突变类型。后来，在泰国、印度尼西亚和缅甸也检测到了相同的突变形式，表明它在东南亚地区广泛分布。在缅甸，也发现了许多疟疾和卵形疟原虫感染。对越南发现的疟疾和卵形疟原虫的突变类型也进行了检测。相比之下，在印度尼西亚只发现了六个疟疾样本和两个卵形疟原虫样本。一份疟原虫样本是相同的新类型，但其他样本都是正常的。

Field survey of malaria was conducted in Thailand, Indonesia, Myanmar and China using an acridine orange (AO) staining method. Diagnostic results were compared with those by microtiter plate hybridization (MPH), and a nested PCR methods.1. In Thailand, a total of 548 samples were obtained, and many P.malariae and P.ovale infections diagnosed by the AO method were confirmed by the MPH and/or nested PCR methods. Their prevalence reached about 20% and 2.2%, respectively. In addition, three samples of P.ovale infections were AO-positive but MPH-negative. Analysis of the target sequences revealed that these isolates were the same mutated type (two nucleotide deletion and one nucleotide substitution) with that found in Vietnam. On the other hand, P.falciparum isolates were found to possess a point mutation at the target region in the 18S rRNA gene.2. In China, many P.malariae infections were also detected from the Sichuan Province by the three methods. By the nested PCR method, a long deletion from amplified PCR product was found at the probe region, indicating that this may be a new mutated type of P.malariae. Later, the same mutated form was detected from Thailand, Indonesia, and Myanmar, indicating that it is widely distributing in SEA.3. In Myanmar, many P.malariae and P.ovale infections were also detected. The mutated types of both of P.malariae and P.ovale which had been found in Vietnam was also detected. In contrast, in Indonesia only six samples of P.malariae and only two of P.ovale were found. One sample of P.malariae was the same new type, but others were normal.