**2. Potential options for frame materials other than aluminium, prototype design and manufacturing**

The study involved different research topics/components related to using different materials rather than aluminium to instal HS. First, our team searched, reviewed, and selected different materials to replace aluminium frames, then designed and

#### *Low-Cost Materials for Do-It-Yourself (DIY) Installation of House Screening… DOI: http://dx.doi.org/10.5772/intechopen.107838*

constructed prototypes with those materials. Using Google and other shopping platforms such as Amazon, eBay, and Mercado Libre, from March to April 2019 we sought "mosquito screens", "insect screens", "window screens", and "door screens" in order to identify different potential models and materials that were different from aluminium. As the inclusion criteria, we considered availability in the market, less expensive than aluminium, and suitability for housing structures, such as the ability to keep mosquito nets fixed on doors and windows. After the online review, the team visited local suppliers to check for the availability of the materials in the localregional-national market.

In the initial phase, we designed and built small-scale prototypes (1: 5 of a window and 1:10 of a door) and real-sized versions (average size of 2.20 × 0.95 m for doors and 1.20 × 0.80 m for windows found in houses from different neighbourhoods in Merida) (**Figure 1**). All materials required for installation including rivets, adhesives, screws, nails, fabric, locks, among others, along with some additional information such as handling, time for manufacturing per square meter, were identified, evaluated, and recorded, information later used to calculate the total costs based on the different options (**Table 1**, **Figure 1**). A regular fibber-glass net (brand Herralum®)

#### **Figure 1.**

*Different options and materials for the installation of house screening other than aluminum: (1a−1d) wood, (2a−2c) polyvinyl chloride plastic (PVC), (3a−3c) velcro and (4a−4c) magnets.*


#### **Table 1.**

*Costs associated with different materials that can be used for the construction of frames for house-screening. Costs for installing house-screening per house: including seven windows and two doors. Costs only consider materials and exclude cost of installation (1 USD = \$23.00 MX PESOS).*

with the following dimensions and features: 30 m length × 1.50 m width rolls, colour grey, mesh light 0.6 × .07 mm, density 0.32 mm was used to as blocking barrier.

To replace aluminium for HS frames, several potential options were identified as follows: wood, polyvinyl chloride plastic (PVC), Velcro, and magnets. All these materials can be installed in doors and windows and are less expensive than aluminium. In fact, magnets and Velcro were the less costly options, followed by PVC and wood. Additionally, these were available within local and national markets, and more importantly, easily accessible to the population.

Several options were identified for the installation of HS, including fixed (not mobile), retractable, and removable HS frames. Fixed insect HS screens are the most common insect screens, not mobile and held by a stable frame. Like fixed HS, retractable screens are also fixed, but they can be opened/closed with a "rolling" system. Finally, removable screens use adhesive or magnetic elements, contain a temporarily fitting system, and are usually an "easy DIY installation". All of these options are versatile and functional with an enriched market, including numerous accessories and colours that you can choose from.

#### **3. Evaluation of prototypes in experimental huts**

On March 2019, a trial following a 6 × 6 Latin-square experimental design was performed to evaluate the HS installation in experimental huts at the unidad colaborativa para bioensayos entomologicos (UCBE) in Merida using different low-cost prototype options vs. the gold standard (aluminium frames) (**Figure 2**). We quantified the entomological impact (entry or exclusion) of each of the different materials/installation as a physical barrier against female *Ae. aegypti* mosquitoes using experimental huts as testing systems. Experimental huts are simplified, standardised representations of human habitations that provide model systems to evaluate mosquito responses to different control methods [24, 25].

Mosquito screens (with regular fibber-glass net, brand Herralum®) with each of the different framing materials were made as real-sized doors (2.20 × 0.95 m) and fixed on an entrance located within the release tunnel of experimental huts (**Figure 2**). *Low-Cost Materials for Do-It-Yourself (DIY) Installation of House Screening… DOI: http://dx.doi.org/10.5772/intechopen.107838*

**Figure 2.** *(a and b) Experimental huts and (c–f) experimental layout of the different options and materials tested.*

All the other entries-exits of the hut were sealed. The mosquito-door-screens of each material were fixed with its corresponding method of installation (**Figure 1**) and evaluated for a 24-hour period, and next day swapped of the hut until a total of six replicates were completed following the Latin-square experimental design. One of the huts was always left without protection as control.

Groups of 2–5 days-old and non-fed female *Ae. aegypti* mosquitoes (New Orleans F3 strain reared at UCBE) (n = 100), were released in the tunnel of the experimental huts in the morning (8:30 a.m) and collected 24 hours later. A BG-sentinel mosquito trap [26] with its bait (weight 1.7 kg, Dimension 38 × 47, ventilator 12 V dc 3.6 watt.) added with CO2 (generation rate of 200 ml/min) [10, 27], was set inside the hut and active for collections for the whole 24-h period. In addition, the interior of the hut was revised, and any mosquito found was collected with Prokopack aspirators [10]. Mosquitoes that did not enter were collected (from the tunnel and outside the hut) with Prokopack aspirators. The collected mosquitoes were kept in a recovery bottle and then stored at −20°C for counting. Data was computed as the difference between initial mosquito abundance (adult) and the values at 24 hours post-release.


#### **Table 2.**

*Efficacy of protection (relative to the control treatment) against* Aedes aegypti *(entry of mosquitoes) with frames constructed from different materials in the experimental huts. A total of 100 adult female* Ae. aegypti *mosquitoes were released into entry chamber in each treatment (n = 6 huts): Control, velcro, Magnet, PVC, Wood, and Aluminum.*

**Table 2** presents the comparative results of the efficacy of frames constructed from different materials and their protection against *Ae. aegypti* (entry of female mosquitoes) in the experimental huts. All HS options had a high efficacy (>93%) in preventing female mosquitoes from passing inside the huts once compared with the control huts with no-screen. The aluminium-based HS showed the highest protection by blocking 99% of female mosquitos going inside the households (IRR = 0.01, C.I. 0.003–0.02); however, the low-cost options which cost is 60% lower than aluminium, also performed well as follow: magnets (Average protection = 93.1%, 95% CI = 89.6– 96.7) and Velcro (Average protection = 92.9%, 95% CI = 88.9–97.0).

#### **4. Consumer opinion and small company's perspective on HS prototypes**

Here, to investigate people's perception of low-cost materials to replace aluminium frames, we applied a questionnaire (**Table 3**) to 55 families that had previously received the installation of HS with aluminium frames (July–August 2019) as part of the cohort project [22, 23]. In this survey, participants were asked about the distinct material options as if they would be hypothetically installed on their houses to replace aluminium frames. Questions included whether they have any previous knowledge or experience with the alternative materials/frames, perception of the cost of the materials, durability, aesthetics, the installation process, and their preferences (if any) for a specific type of frame. During this process, smallscale prototypes constructed were shown as well as the pictures of the real-sized prototypes installed in a house (**Figure 1**) to people, but no other explanation was given to avoid bias in answers.

A high percentage of the participants interviewed were women (76.36%, 42/55) with ages ranging between 30 and 50 years old (54/55); all of them were married and heads of families from houses that had received the HS installation previously as part of the cohort project. Frames made of wood (62%, 34/55) were the most "popular" alternative among the participants, followed by magnets (45%, 25/55), PVC (45%, 25/55), and Velcro (29%, 16/55). People acknowledged the existence of wood frames, but the other materials v.gr. PVC, Velcro, and magnets were "uncommon" to them; although some participants recalled having seen the other options on the Internet, magazines, or TV programs. Regarding the cost, 45–60% of participants believed that the prices of the four different frames were between 5 and 50 USD, and they thought Velcro and magnets were expensive. The expected durability of the materials was associated with weather conditions, but most participants thought that all materials were highly resistant (which could last 1–5 years). On the aesthetics, which is the perception of "how beautiful" the frames can be seen on the houses, the wood option got the best scores (73%, 40/55), followed by magnets (56%, 31/55). More than 50% of the interview participants thought all the options were easy to instal; however, many of them disagreed on how easy to maintain them. All materials were seen as an acceptable positive improvement of the house except for PVC.

We also investigated the perspective of A&MS businesses on the prototypes/materials (November–December 2020). To do so, A&MS companies located in Merida, Yucatan were identified (n = 100) by searching on Yellow pages. Because of COVID-19 pandemic, person-to-person contact was avoided, so telephone calls were used to reach them. Forty companies dedicated to the assemblage of HS in the city of Merida were surveyed (**Table 4**). Participants were asked about costs, durability, aesthetics,


#### **Table 3.**

*Results recorded from householders about alternative frame materials other than aluminum for the installation of house-screening in Merida, Mexico.*

perceived comfort, acceptance, and an open section on the customer preferences from entrepreneurs' perspectives, and the production-manufacturing process of the HS (**Table 4**). Small-scale prototypes and a photographic catalog of the different prototypes (**Figure 1**) were also employed.

*Mosquito Research - Recent Advances in Pathogen Interactions, Immunity, and Vector Control…*


#### **Table 4.**

*Perspectives of professional small companies dedicated to the installation of house-screening about potential lowcost alternatives to replace aluminum frames.*

We identified "producers", those who manufacture and instal HS, and "distributors" who only sell materials for HS. Fifty-five percent of (22/40) the companies declared to be in the formal sector and the remaining 45% (18/40) were informal. Of those in the formal sector, 59.09% (13/22) were producers, the remaining 40.90% (9/22) were distributors, and the informal ones were only producers. Only one producer (1/31) made mosquito nets with one of the alternative materials (wood).

The interviewed producers declared that the alternative material most requested by consumers after aluminium was wood (41.93% [13/31]) (**Table 4**) and that few of them had received requests for PVC (9.67% [3/31]); and recalled that customers had never requested them for Velcro or magnets. Respondents considered aluminium to be an expensive material (97.5% [39/40]); despite not working with alternative materials, some considered wood and PVC were cheaper (7.5% [3/40], 12.5% [5/40], respectively), and considered that Velcro and magnets were the less expensive options (52.5% [21/40], 57.5% [23/40]) (**Table 4**). Regarding the duration of the alternative materials, they expected an average extent of 21.9 months for wood, 21.2 months for PVC, 8.4 months for Velcro, and 9.6 months for magnets (**Table 4**). Wood and magnets (57.5% [23/40], 47.5% [19/40]) were considered the most aesthetical alternative materials for the elaboration of HS (**Table 4**). Regarding whether alternative materials are easy to manufacture and maintain, many of the interviewees could not answer because they do not know enough about the material to give a real opinion (**Table 4**). However, those who responded considered that the alternative materials were easy to manufacture and maintain.

Although alternative materials are considered cheaper, aesthetic, easy to maintain and instal by A&MS small companies, they declared not willing to use this type of materials and rejected the use of Velcro (97.5% [39/40]), PVC (90% ([36/40]), magnets (82.5% [33/40]) and wood (77.5% [31/40]). Nevertheless, they acknowledged that consumers could request these materials, with wood being the material with the highest potential to be requested (43.1%), followed by PVC and magnets (22.5%) and finally Velcro (14.4%).

*Low-Cost Materials for Do-It-Yourself (DIY) Installation of House Screening… DOI: http://dx.doi.org/10.5772/intechopen.107838*

#### **5. Conclusions**

In this study, we examined the efficacy of low-cost frames built using different materials (e.g. wood, PVC, Velcro) to protect against *Ae. aegypti* getting inside experimental huts. All HS frame prototypes described here were highly effective in blocking the entry of *Ae. aegypti* mosquitoes (>93%), and even without "total" protection, entry was lower compared to no netting. Of note, all the prototype frames of HS made of different materials rather than aluminium, were low-priced. For instance, HS made with magnets and Velcro performed very well against mosquitoes and had a 54–68% lower cost than aluminium. Thus, it was estimated that protecting a house (with seven windows and two doors) using these no-aluminium materials costs about US\$35 [22].

Additionally, we investigated people's perceptions of using different materials to build HS. The most "popular" and more commonly used alternative was the wooden-made frame (62%) compared to magnets, Velcro, and PVC-based frames; this latter was considered the "least popular" material as it was not considered a positive improvement to the houses. To mention, aluminium is usually associated with quality and aesthetics, as well as an improvement of the home, which poses an enormous burden on using low-cost materials as these must be aesthetically accepted by the community to be perceived as an improvement in the quality of their housing and living conditions. On top of this, little or no information on the characteristics, effectiveness, cost, and availability of the different materials used to build HS rather than aluminium are available; therefore, this latter is considered the only option to build HS, limiting people's perspective on installing not-aluminium-based HS in their houses, instead leaving them unprotected.

During the interviews, people learned about these low-cost options through demonstration prototypes and expressed their doubts; expanding their options to request from A&MS or to assemble and instal themselves in their homes. Small A&MS businesses, being more accessible, provide an important service to the population, especially the low-income population. Therefore, producers and consumers need information and alternatives to evaluate. Thanks to the companies surveyed, we know that they tend to produce 30 units of aluminium mosquito nets (for one window) per month, costing on average USD 14.83 each and with an approximate profit of 40%. It will last almost 10 years and the professional service, if any, is only to change the broken/damaged ones. It would be useful to show the benefits of all the different alternatives for established producers; for example, Velcro and magnets are the materials with the highest benefits, derived mainly from the short lifetime, which increases the frequency of purchases. However, they are also easy for users to instal themselves at home.

Overall, these results support the possibility of using alternative, accessible, and less expensive materials such as wood, PVC, Velcro, and magnets, instead of aluminium-based HS to protect people's houses against *Ae. aegypti* invasion inside households. This study changes the paradigm between the A&MS seeking to maximise their profit and the consumers seeking cheaper costs. According to the A&MS, the quality and durability of aluminium are unmatched, and they do not have the "social benefit" of consumers as a policy. Low-income people are constrained by the cost of conventional house screens and the labor involved; unaware of alternative models, their households lack protection against *Ae. aegypti.* Therefore, this study suggests strategies involving the government, the private sector, and academia for disseminating and accessing these low-cost alternative materials, either through micro-credits, vouchers for people at risk (e.g., pregnant women), or partial or monthly payments.
