Field Trial of Netlon
Trial area and trial village
Villages in the northern and eastern parts of the Vhembe district, Limpopo province, ar situated in a medium to high risk malaria zone. Spraying for vector control does occur in many of the villages. The trial village is partly sprayed during the annual malaria spraying programme. In addition to mosquitoes, people living in this area are also exposed to annoying and biting insects. The housing in the village consists of traditional mud huts with thatched roofs and brick and cement houses with mostly metal or tiled roofs (western styled houses). The trial was performed on homes in the unsprayed section of the village.
A total of 40 households (20 traditional mud huts and 20 western style houses) were included in the trial. The Netlon® lining was installed in the sleeping room of the household. Data was collected using a questionnaire and physical observation of the linings. A trained field worker fluent and familiar in the local language and culture conducted the interview. Participants were people who mostly slept in the sleeping area. Participants were enrolled prior to installation of the linings and an enrolment questionnaire was completed, which served as a baseline for future questionnaires.
The Netlon® lining was installed on the upper parts of the wall near the roof. Wooden strips were first bolted onto the wall. The lining was then fixed on these wooden strips using Velcro® tape. One part of the Velcro® tape was attached onto the wooden strip using the adhesive side. The Netlon® lining was then fixed in between the two Velcro® tape parts (male and female). Each respective type of lining (Table 19) was installed in eight sleep areas (four huts and four houses).
Overall user acceptability, lining durability and perceived effectiveness of linings.
Face to face interviews to ascertain the overall user acceptability, lining durability and perceived effectiveness of linings were done monthly over a period of six months. Questions focused on the use of household pesticides and cleaning products within the sleeping area for that month; perceived activity of insects in the sleeping area since the lining was installed; physical change of the lining such as damage and discolouration, integrity of the installation and perceived adverse effects on the occupants and domesticated animals that might have had access to the sleeping area.
Field trial results and discussion
Only one western style house had ever been sprayed by DDT spray workers to prevent malaria, whilst 35% of the huts had been sprayed. None of dwellings were sprayed less than six years ago based on what the participants could remember. Not all participants were head of the house or kept the spraying records, so they did not necessarily have accurate information on the spray history of the dwelling. In general, 30% of participants in western style houses and 45% in mud huts used insecticides to kill mosquitoes and other nuisance insects. Only two participants in western styled houses indicated that they had an untreated mosquito net to sleep under, which they have used before. In general 40% in western styled houses and 60% in huts had burnt mosquito coils before.
All participants except for one had an electricity connection to their home during the field trial. This made it possible to use electric drills to install wooden strips for attaching the wall linings. The general features of the households involved in the field trial are shown in Table 20.
2. A review of physical, chemical and biological malaria vector control interventions .
2.1 Vector elimination
2.2 Preventing mosquito bites
2.3 Killing mosquitoes after they have bitten
2.4 Future developments in vector control
2.5 Limitations (gaps) of current vector control interventions
3. Problem statement
3.1. Aim .
4. Development of ITWL
4.4 Work pla
4.8 Field Trial of Netlon®
5. Conceptual development of a mosquito repellent bracelet
5.2 Problem statement
5.6 Work plan.
5.10.1 Free absorption of DEET by EVA matrix
5.11 Discussion .
6. Overall discussion
7. Overall conclusions and recommendations
8. Publications and conference presentations