**8. Final considerations**

integrated in brigades separated from other health activities that were not exclusively linked to vector control. This resulted in an independent organization with equipment, vehicles, machinery and supplies (insecticides) that has been growing hand-in-hand with the problem. With IVM, a more rational use of resources is proposed, starting with the multi-sector and multidisciplinary nature (social participation) of the approach, where the social communica-

The incorporation of GMM-BCMW into the vector control programs involves the components proposed for IVM, but also requires adaptation of the technology to the local conditions, as well as the development of an infrastructure of basic technology (insectariums and laboratories) to permit mass, sustained production, implementation and appropriate evaluation of the interventions. In this case, a specialized multidisciplinary group—in addition to technical personnel—is needed to achieve the introduction, monitoring and evaluation of new inter-

*Coverage*: A problem inherent to the traditional programs of control in urban and suburban areas in countries where ABD are endemic is their limited coverage; not all breeding sites can be protected or removed, and their productive potential cannot be eliminated with biological, chemical or physical agents. It is not possible to protect or control the totality of the most productive and stable breeding sites in urban centers due to their number, seasonal productivity,

The coverage of a vector control program functions at the level of the individual, the household, the block or neighborhood, but rarely at the town level. With the IVM programs, the target for intensive application of control efforts will be the neighborhood and towns at greatest risk; there are no claims that all affected areas, neighborhoods or towns will be covered. Coverage in the case of GMM-BCMW can include areas, towns, or medium-sized urban centers, since the mass release of treated mosquitoes cannot limit itself to blocks or a neighborhood. Thus, monitoring and maintenance in such broad areas is complicated by the necessity of technical and (specially trained) human resources and not presently contemplated by

*Scale*: One of the most important challenges for any vector control intervention is reaching a level of sufficient coverage (breeding sites, houses, people or communities) in order to effectively limit transmission. These technological innovations are proposed as intervention at a scale larger than that established by traditional vector control strategies. However, all of the processes of production, introduction and maintenance must be initially evaluated at an inter-

Their application for control of mosquitoes that transmit disease is today only viewed within the context of the strategy of integrated vector management (IVM). This implies necessary adaptations in control programs as regard production of biological materials as well as in relation to the operation, which should be designed in accordance with the technical specifica-

mediate scale before considering their application at the regional or national level.

tion component is incorporated as a substantial element of this strategy.

ventional strategies.

surveillance programs.

tions of the modified organisms.

location and access ("cryptic" breeding sites).

104 Dengue Fever - a Resilient Threat in the Face of Innovation

During the last decade, the WHO has been promoting IVM but has been using only those intervention methods traditionally available. Several innovative methods are being developed to complement the current control of *Ae. aegypti* populations and affect the transmission of ABD. Some show great potential, such as the use of GMM-BCMW, but are not yet available as part of institutional prevention and control programs. In addition to the challenges exposed earlier, other limitations include a lack of scientific and technological infrastructure of the quality and capacity necessary for the implementation of novel methods of mosquito control. This extends to laboratories, systems for the mass rearing of mosquitoes and processes such as quality control, transportation, field release, monitoring and evaluation of effectiveness. Both WHO and the Pan American Health Organization (PAHO) are offering their technical cooperation to support pilot studies using innovative methods. The technical advisory group on entomology in public health and vector control explicitly recommended to PAHO "Promoting rapid, robust and accelerated evaluation of new tools complementary to the control of *Aedes*, with particular attention to the use of mosquitoes infected with the bacteria *Wolbachia* and sterile and genetically modified insects."

of the effects of different vector control interventions on the impact of the illness within the community (infection, severity of clinical cases, mortality, etc.). These limitations are the same for GMM-BCMW, and we still need indicators that will correlate efficacy in terms of entomological parameters (reduction or substitution of mosquito populations) to effects on

Challenges for the Introduction and Evaluation of the Impact of Innovative *Aedes aegypti*…

http://dx.doi.org/10.5772/intechopen.79862

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Entomological surveillance is indispensable in order to monitor vector populations and to count on the basic parameters that allow for evaluation of direct impact on affected populations. Larval densities are not sufficient for evaluating the effects expected with the inclusion of these innovations, since the introduced populations are competing adults; as a result, it is necessary to evaluate adult density (males and females) as well as vector survival, mating

Last but not least, the success of any control intervention should be measured ultimately in terms of resultant decrease in infection transmission and in the impact of the illness on the community. This process entails decreased herd immunity in human populations and would introduce the risk of greater epidemics if the intervention measures lost intensity or effectiveness or were no longer applied. Decreased immunity augments the population's susceptibility, which results in lower vector density thresholds for transmission or risk of transmission. Here, we have exposed some of the major challenges for the introduction, implementation and evaluation of innovative *Aedes aegypti* control strategies based on GMM/BCMW. Nowadays, they are still being evaluated to gauge their entomological impact; and evidence of epidemio-

Other basic requirements for the adoption of technological innovations include a regulatory and legislative framework for their use in public health (Environmental, Biosecurity and Bioethics); following a set of Protocols & Portfolio having to do with safety, quality control, efficacy, and so on; and necessary integration with local vector control programs including agreement/acceptance by institutions and communities. In terms of administrative and financial requirements, we still need to resolve whether these technological innovations can be acquired under the current budget structure (as a product or service). In order to more quickly implement these new technologies, we need to develop a medium to long-term implementation and financing plan; production, distribution, monitoring and evaluation logistics and

To the Canadian Institutes of Health Research (CIHR) and IDRC (Preventing Zika disease with novel vector control approaches Project 108412) and Fondo Mixto CONACYT–Gobierno del Estado De Yucatán (Project YUC-2017-03-01-556). Abdiel Martin-Park is supported by the Cátedras–CONACYT program. Special thanks to Ana García-Moreno Malcolm for grammar

transmission of the illness.

habits, reproductive capacities (fecundity) and so on.

logical impact is desirable in the near future.

private-public partnerships.

**Acknowledgements**

corrections.

Vector control programs do not use "single" methods. Innovations should be considered complementary tools to control programs, not substitutes. Traditional and/or new interventions of greater complexity can be implemented proactively using a risk stratification approach calling for different intensity and greater coverage in priority areas. However, we can anticipate complications on monitoring and evaluation, since there is little evidence and experience of multiple or combined interventions with intersectoral participation and IVM.

Traditional vector control has demonstrated limited impacts and transitory decreases in larval and adult mosquito populations. Monitoring of these traditional control programs is performed on an irregular basis throughout the year, without taking into account that there are important seasonal effects on vector populations. Furthermore, these evaluations are unstructured and usually not conduced at the time intervals necessary in order to estimate the magnitude and longevity of the effects on vector populations. In the case of GMM-BCMW, in addition to performing entomological monitoring to estimate the effects of suppression on target populations, in the case of substitution or population replacement strategies, it is necessary to include measurements of the reproductive and biological performance of the introduced populations.

Estimates of the effect of traditional actions (larval density) do not imply impacts on disease transmission (incidence). The IVM strategies share these limitations, although they diversify the indicators due to the multidisciplinary nature of their interventions. In the case of GMM-BCMW, the evaluations ought to incorporate continuous monitoring of adult mosquito populations (wild and introduced): their survival, performance (or *fitness*), competence as vectors or capacity to transmit the infectious agents, reproductive capacities, flight range, dispersal, and so on. The indicators should purvey information relevant to measuring the effects on reproductive capacity; reduction in infection and other entomological, epidemiological and even ecological parameters that describe the dynamics of adaptation of introduced populations.

Despite intense research on *Ae. aegypti*, we still do not have entomological parameters linking vector density to risk of transmission. It is also still difficult to define the transmission risk's direct impact on human populations and its duration (days, weeks and months) in mosquito populations—and even more difficult to count on indicators that allow for efficient evaluation of the effects of different vector control interventions on the impact of the illness within the community (infection, severity of clinical cases, mortality, etc.). These limitations are the same for GMM-BCMW, and we still need indicators that will correlate efficacy in terms of entomological parameters (reduction or substitution of mosquito populations) to effects on transmission of the illness.

Entomological surveillance is indispensable in order to monitor vector populations and to count on the basic parameters that allow for evaluation of direct impact on affected populations. Larval densities are not sufficient for evaluating the effects expected with the inclusion of these innovations, since the introduced populations are competing adults; as a result, it is necessary to evaluate adult density (males and females) as well as vector survival, mating habits, reproductive capacities (fecundity) and so on.

Last but not least, the success of any control intervention should be measured ultimately in terms of resultant decrease in infection transmission and in the impact of the illness on the community. This process entails decreased herd immunity in human populations and would introduce the risk of greater epidemics if the intervention measures lost intensity or effectiveness or were no longer applied. Decreased immunity augments the population's susceptibility, which results in lower vector density thresholds for transmission or risk of transmission.

Here, we have exposed some of the major challenges for the introduction, implementation and evaluation of innovative *Aedes aegypti* control strategies based on GMM/BCMW. Nowadays, they are still being evaluated to gauge their entomological impact; and evidence of epidemiological impact is desirable in the near future.

Other basic requirements for the adoption of technological innovations include a regulatory and legislative framework for their use in public health (Environmental, Biosecurity and Bioethics); following a set of Protocols & Portfolio having to do with safety, quality control, efficacy, and so on; and necessary integration with local vector control programs including agreement/acceptance by institutions and communities. In terms of administrative and financial requirements, we still need to resolve whether these technological innovations can be acquired under the current budget structure (as a product or service). In order to more quickly implement these new technologies, we need to develop a medium to long-term implementation and financing plan; production, distribution, monitoring and evaluation logistics and private-public partnerships.
