Appawu Maxwell, Owusu-Agyei Seth, Dadzie Samuel, Asoala Victor, Anto Francis, Koram Kwadwo, Rogers William, Nkrumah Francis, Hoffman Stephen L, Fryauff David J
Noguchi Memorial Institute for Medical Research, Legon, Accra, Ghana.
Trop Med Int Health. 2004 Jan;9(1):164-70. doi: 10.1046/j.1365-3156.2003.01162.x.
We studied the malaria transmission dynamics in Kassena Nankana district (KND), a site in northern Ghana proposed for testing malaria vaccines. Intensive mosquito sampling for 1 year using human landing catches in three micro-ecological sites (irrigated, lowland and rocky highland) yielded 18 228 mosquitoes. Anopheles gambiae s.l. and Anopheles funestus constituted 94.3% of the total collection with 76.8% captured from the irrigated communities. Other species collected but in relatively few numbers were Anopheles pharoensis (5.4%) and Anopheles rufipes (0.3%). Molecular analysis of 728 An. gambiae.s.l. identified Anopheles gambiae s.s. as the most dominant sibling species (97.7%) of the An. gambiae complex from the three ecological sites. Biting rates of the vectors (36.7 bites per man per night) were significantly higher (P<0.05) in the irrigated area than in the non-irrigated lowland (5.2) and rocky highlands (5.9). Plasmodium falciparum sporozoite rates of 7.2% (295/4075) and 7.1% (269/3773) were estimated for An. gambiae s.s. and An. funestus, respectively. Transmission was highly seasonal, and the heaviest transmission occurred from June to October. The intensity of transmission was higher for people in the irrigated communities than the non-irrigated ones. An overall annual entomological inoculation rate (EIR) of 418 infective bites was estimated in KND. There were micro-ecological variations in the EIRs, with values of 228 infective bites in the rocky highlands, 360 in the lowlands and 630 in the irrigated area. Approximately 60% of malaria transmission in KND occurred indoors during the second half of the night, peaking at daybreak between 04.00 and 06.00 hours. Vaccine trials could be conducted in this district, with timing dependent on the seasonal patterns and intensity of transmission taking into consideration the micro-geographical differences and vaccine trial objectives.
我们研究了加纳北部拟用于疟疾疫苗测试的卡塞纳-南卡纳区（KND）的疟疾传播动态。在三个微观生态地点（灌溉区、低地和岩石高地）使用人饵诱捕法进行了为期1年的密集蚊虫采样，共捕获18228只蚊子。冈比亚按蚊复合种和费氏按蚊占总捕获量的94.3%，其中76.8%捕获自灌溉社区。其他捕获数量相对较少的种类有法老按蚊（5.4%）和棕足按蚊（0.3%）。对728只冈比亚按蚊复合种进行分子分析，确定冈比亚按蚊指名亚种是来自这三个生态地点的冈比亚按蚊复合种中最主要的姐妹种（97.7%）。媒介的叮咬率（每人每晚36.7次叮咬）在灌溉区显著高于非灌溉低地（5.2次）和岩石高地（5.9次）（P<0.05）。估计冈比亚按蚊指名亚种和费氏按蚊的恶性疟原虫子孢子率分别为7.2%（295/4075）和7.1%（269/3773）。传播具有高度季节性，最严重的传播发生在6月至10月。灌溉社区人群的传播强度高于非灌溉社区。卡塞纳-南卡纳区的总体年度昆虫接种率（EIR）估计为418次感染性叮咬。EIR存在微观生态差异，岩石高地为228次感染性叮咬，低地为360次，灌溉区为630次。卡塞纳-南卡纳区约60%的疟疾传播发生在夜间后半段的室内，在凌晨04:00至06:00之间达到高峰。可以在该地区进行疫苗试验，时间安排取决于传播的季节性模式和强度，同时考虑微观地理差异和疫苗试验目标。
