Sabtiu Abdul Rahim Mohammed, Sraku Isaac Kwame, Mfum Christopher Owusu-Asenso, Akuamoah-Boateng Yaw, Doe Richard Tettey, Boadu Emmanuel Nana, Azumah Judith Dzifa, Eyeson Nana Aba, Abdulai Anisa, Amoateng Godfred, Attah Simon Kwaku, Aboagye-Antwi Fred, Afrane Yaw Asare
University of Ghana.
Res Sq. 2025 Feb 14:rs.3.rs-6008722. doi: 10.21203/rs.3.rs-6008722/v1.
Urban malaria transmission in sub-Saharan Africa is often underestimated, emphasizing the need for research on vector distribution, abundance, behavior, and infectivity in cities. Since 2003, urban malaria transmission has intensified. Monitoring populations is crucial for developing effective interventions. This study examined the biting and resting habits, distribution, abundance, and infection of malaria vectors in Accra.
Adult malaria vectors were collected using human landing catch (HLC) and Prokopack aspiration (PPK) at ten sites in Accra, categorized into five groups: sites with Irrigated Urban Farming (IUF), Lower Socioeconomic Status (LS), Middle Socioeconomic Status (MS), High Socioeconomic Status (HS), and Peri-urban (PU) areas. Biting patterns and entomological transmission indices of s.l. were assessed, Molecular methods were used to detect sporozoite infection, bloodmeal sources, vector species, and insecticide resistant mutation genes.
A total of 41,747 mosquitoes were collected. Of these, 95.49% (39,863/41,747) were host-seeking collected through human landing catch (HLC), consisting of (52.54%, 20,945/39,863), (42.00%, 16,742/39,863), (3.74%, 1,491/39,863), and Mansonia (1.72%, 685/39,863). The remaining 4.51% (1,884/41,747) were resting mosquitoes collected using a Procopack aspirator, comprising (31.26%, 589), (57.21%, 1,078), and (11.52%, 217). Overall, the irrigated urban farming (IUF) site category recorded the highest abundance of s.l. (48.63%, 10,466/21,520), followed by the peri-urban (PU) site category (18.06%, 3,887/21,520), high socioeconomic (HS) site category (16.42%, 3,533/21,520), middle socioeconomic (MS) site category (13.74%, 2,956/21,520), and low socioeconomic (LS) site category (3.15%, 678/21,520) in both HLC and Procopack collections.Significantly higher mosquito biting activity was observed during the late evening (LE), the classical mosquito biting time, in both the rainy (71.45%, 11,337/15,865) and dry (72.21%, 3,658/5,066) seasons. Indoor An. gambiae s.l. had higher sporozoite infectivity (70.64%, 77/109) than outdoor mosquitoes (29.35%, 32/109) (χ = 6.78, P = 0.009). Tuba from the IUF site had the highest sporozoite infectivity (32.11%, 35/109), with higher indoor (24.77%, 27/109) than outdoor (7.34%, 8/109) rates.
s.l. drives urban malaria transmission in Accra, with high human bloodmeal indices and sporozoite infectivity, especially indoors. Urban agriculture promotes vector proliferation. Targeted indoor control and management of breeding sites in IUF areas are essential to reduce transmission.
撒哈拉以南非洲地区的城市疟疾传播情况常常被低估，这凸显了对城市中病媒分布、数量、行为和感染性进行研究的必要性。自2003年以来，城市疟疾传播有所加剧。监测人群对于制定有效的干预措施至关重要。本研究调查了阿克拉市疟疾媒介的叮咬和栖息习性、分布、数量及感染情况。
在阿克拉的十个地点，采用人饵诱捕法（HLC）和Prokopack吸捕法（PPK）收集成年疟疾媒介，这些地点分为五组：灌溉式城市农业（IUF）区、低社会经济地位（LS）区、中等社会经济地位（MS）区、高社会经济地位（HS）区和城郊（PU）区。评估了按蚊复合体的叮咬模式和昆虫学传播指数，采用分子方法检测子孢子感染、血餐来源、病媒种类及杀虫剂抗性突变基因。
共收集到41747只蚊子。其中，95.49%（39863/41747）是通过人饵诱捕法（HLC）收集的宿主寻找蚊，包括冈比亚按蚊（52.54%，20945/39863）、阿拉伯按蚊（42.00%，16742/39863）、塞内加尔按蚊（3.74%，1491/39863）和曼蚊属（1.72%，685/39863）。其余4.51%（1884/41747）是使用Prokopack吸捕器收集的栖息蚊，包括冈比亚按蚊（31.26%，589只）、阿拉伯按蚊（57.21%，1078只）和塞内加尔按蚊（11.52%，217只）。总体而言，在人饵诱捕法和Prokopack吸捕法收集的样本中，灌溉式城市农业（IUF）地点类别记录的按蚊复合体数量最多（48.63%，10466/21520），其次是城郊（PU）地点类别（18.06%，3887/21520）、高社会经济地位（HS）地点类别（16.42%，3533/21520）、中等社会经济地位（MS）地点类别（13.74%，2956/21520）和低社会经济地位（LS）地点类别（3.15%，678/21520）。在雨季（71.45%，11337/15865）和旱季（72.21%，3658/5066）的傍晚时分（LE），即典型的蚊子叮咬时间，观察到显著更高的蚊子叮咬活动。室内冈比亚按蚊复合体的子孢子感染性（70.64%，77/109）高于室外蚊子（29.35%，32/109）（χ = 6.78，P = 0.009）。IUF地点的图巴村子孢子感染性最高（32.11%，35/109），室内感染率（24.77%，27/109）高于室外（7.34%，8/109）。
按蚊复合体在阿克拉市推动城市疟疾传播，具有较高的人血餐指数和子孢子感染性，尤其是在室内。城市农业促进了病媒繁殖。在IUF地区有针对性地进行室内控制和繁殖地管理对于减少传播至关重要。
