1) Recommended approaches for immediate inclusion in PNCD

In this category three initiatives were included. All of them have been previously tested in some Brazilian municipalities with satisfactory results and were considered viable to be incorporated into the country's control actions without a significant impact on the program costs or routine:

- The strategy known as eco-bio-social, which focuses on social participation and environmental management in controlling the vector.¹¹ This approach significantly reduced the vector density in Fortaleza, Ceará State, and is already being applied in two other municipalities, as requested by the Ministry of Health: Goiânia, Goiás State, and Belo Horizonte, Minas Gerais State.

- The risk mapping takes into consideration the spatial heterogeneity in the distribution of infections. This methodology uses relatively simple methods to identify areas that persistently accumulate dengue cases. The proposal, in this context, is to enhance the interventions in those areas.^12,13

- The spread of larvicide mediated by the mosquitoes themselves, which act as disseminators.¹⁴ The strategy is based on the fact that A. aegypti females spread their eggs in many breeding sites, reaching breeding spots that are inaccessible to men, especially in urban environments which are disorganized and are in a vulnerable situation. Mosquito mediated pyriproxyfen dispersion, the larvicide currently used by the PNCD, was conducted in the Amazon region by previously trained endemic control agents. A reduction of the vector density of at least ten times was verified.¹⁵

2) Recommended approaches for inclusion in PNCD in special situations

In this category, actions aiming the protection of pregnant women, considered a priority group on the epidemic of Zika virus, were listed. For this group, the recommendation was to include in the routine of the Program the use of window and door screens, with or without insecticides, to keep the mosquitoes away, the distribution of repellents for personal protection and the possibility of intradomiciliar insecticide spraying. However, the impact of these measures on the budget of Brazilian cities, even if applied only to this particular group of people, is an issue that cannot be overlooked. Restricting public resources to be used primarily on protecting public places, such as health facilities and schools, is a possibility to be considered.

3) Potentially promising technologies

This category included strategies that cannot be incorporated immediately in the PNCD either because their cost is incompatible with the available public resources, or because the schedule for national-level implementation is not feasible in the short-term, or even because they add important operational issues, such as a deep change in the routine of health agents - which requires time and planning. Wolbachia-infected mosquitoes, sterile mosquitoes and the application of spatial repellents for homes were added here.

Sterile males aim to reduce vector populations. Their sterilization is achieved genetically (transgenic mosquitoes) or through irradiation.^5,6 Females inseminated by sterile males do not generate a viable offspring. Nevertheless, this approach requires a frequent release of massive amounts of sterile males in order to become powerful against vector populations. This is especially relevant in the case of irradiated specimens, who have their survival and viability jeopardized by the process.

The idea behind Wolbachia-infected mosquitoes is different: these mosquitoes are intended to have a dual function, both reducing and replacing the original populations. The presence of these bacteria, precludes or impairs mosquito infection with the dengue and chikungunya virus.¹⁶ There is evidence that it also happens with Zika virus¹⁷. The introduction of Wolbachia in A. aegypti does not involve genetic engineering. This strategy has a sustainability component missing from the sterile males' technology: Wolbachia-infected females produce more offspring than wild females. Since all eggs derived from those females are already born containing Wolbachia, there is no need for frequent releases of mosquitoes. Besides, wild females inseminated by Wolbachia-infected males cannot produce offspring, causing a reduction in the original population.¹⁸

There is also a strategy that combines Wolbachia-infected males and irradiation. By using this procedure, already performed with Aedes albopictus, it is not necessary, before releasing females in the field, to separate them from males in the laboratory - one of the most expensive stages of the technique. In this case, the sterilization of males happens due to the presence of Wolbachia and the irradiation is used to sterilize females of this lineage. Because these females are more susceptible to radiation, there is little compromise in the viability of males.¹⁹

It is worth noting that, for both Wolbachia-infected mosquitoes and sterile mosquitoes, the local population partnership is an essential factor. Both methods require strong engagement of communities, since they are based on the release of mosquitoes, a task that is the opposite to the common sense of vector control. This situation reveals an additional evidence of the complexity of this issue and shows that, even if the solution was merely technological, the biomedical technology could not dispense other technologies neither the theoretical-methodological framework typical of human and social sciences, especially information, education and communication.⁹

In addition, a question remains: what is the risk of moving away from the central problem if we give priority essentially to the technical and welfare aspects of vector control? Appropriate medicines are only possible when the diagnostic is correct. Experiences from other countries, and even from some places and situations in Brazil, show that the relation among different government sectors, added to the participation of non-government sectors and the general civil society, are at the basis of a successful control of dengue epidemics.⁹ Yet, the question remains: how to support it?

This overwhelming epidemic of Zika virus is an extreme situation, with no precedents, certainly the biggest health emergency in which all living Brazilians have been through. The population is insecure, and this can lead to panic. In whatever perspective we look at, this is a unique opportunity to rethink our assumptions. From an essentially mercantilist point of view, this situation can be an excellent business opportunity. For some academic sectors, it can constitute a great opportunity to gain visibility and curriculum prestige. But it can also be an opportunity for each person to assume his social responsibility and leave his comfort zone, both individually and collectively.