目的　探索河南省基本消灭疟疾地区疟疾暴发流行程度及原因。　方法　在信阳市二十里河村选择 5个居民组 ,运用寄生虫学与昆虫学方法进行调查。　结果　 1999年 7、8两个月居民带虫发病率为 7.37% ,6月小学生原虫率和疟疾抗体阳性率分别为 2 .0 0 %和 8.40 % ,1998年居民疟史率为 16 .72 % ;仅捕获嗜人按蚊和中华按蚊 ,前者 7、8月份平均叮人率 4.82 ,后者为 6 .77;人血指数前者为 0 .785 7,后者为 0 .15 19;腺子孢子率前者为 0 .0 8% ,后者为 0 ;媒介能量前者为 5 .5 2 96 ,后者为 0 .892 4,前者是后者的 6 .2倍。　结论　嗜人按蚊为当地疟疾的主要传播媒介 ,该蚊的种群数量增加是疟疾暴发流行的主要因素。 Objective To explore the prevalence and causes of malaria outbreak in areas where malaria was basically eliminated in Henan Province. Methods Five residents groups were selected in Twenty Shilihe Village, Xinyang City, and the parasitology and entomological methods were used to investigate. Results The incidence of resident insects was 7.37% in July and August of 1999. The prevalence of protozoan and malaria antibodies in June was 2.0% and 8.40% respectively. In 1998, the rate of resident malaria was 16.72% ; Anopheles anthropophagus and Anopheles sinensis were only captured, the former in July and August average bite rate of 4.82, which is 6 .77; the former is 0.785 7 human blood index, the latter is 0.15 19; gland The former was 0.08% of the sporulation rate, the latter was 0; the former of the medium energy was 5.52 96, the latter was 0.892 4, while the former was 6.2 times of the latter. Conclusion Anopheles anthropophagus is the major transmission medium for malaria in the country. The increased population of this mosquito is a major factor in the outbreak of malaria.