Declining malaria, rising of dengue and Zika virus: insights for mosquito vector control

Abstract

The fight against mosquito-borne diseases is a challenge of huge public health importance. To our mind, 2015 was an extraordinary year for malaria control, due to three hot news: the Nobel Prize to Youyou Tu for the discovery of artemisinin, the development of the first vaccine against Plasmodium falciparum malaria [i.e. RTS,S/AS01 (RTS,S)], and the fall of malaria infection rates worldwide, with special reference to sub-Saharan Africa. However, there are major challenges that still deserve attention, in order to boost malaria prevention and control. Indeed, parasite strains resistant to artemisinin have been detected, and RTS,S vaccine does not offer protection against Plasmodium vivax malaria, which predominates in many countries outside of Africa. Furthermore, the recent outbreaks of Zika virus infections, occurring in South America, Central America and the Caribbean, represent the most recent of four arrivals of important arboviruses in the Western Hemisphere, over the last 20 years. Zika virus follows dengue (which slyly arrived in the hemisphere over decades and became more aggressive in the 1990s), West Nile virus (emerged in 1999) and chikungunya (emerged in 2013). Notably, there are no specific treatments for these arboviruses. The emerging scenario highlights that the effective and ecofriendly control of mosquito vectors, with special reference to highly invasive species such as Aedes aegypti and Aedes albopictus, is crucial. The concrete potential of screening plant species as sources of metabolites for parasitological purposes is worthy of attention, as elucidated by the Y. Tu's example. Notably, plant-borne molecules are often effective at few parts per million against Aedes, Ochlerotatus, Anopheles and Culex young instars, can be used for the rapid synthesis of mosquitocidal nanoformulations and even employed to prepare cheap repellents with low human toxicity. In addition, behaviour-based control tools relying to the employ of sound traps and the manipulation of swarming behaviour (i.e. Blure and kill^approach) are discussed. The importance of further research on the chemical cues routing mosquito swarming and mating dynamics is highlighted. Besides radiation, transgenic and symbiont-based mosquito control approaches, an effective option may be the employ of biological control agents of mosquito young instars, in the presence of ultra-low quantities of nanoformulated botanicals, which boost their predation rates.

Pakistani Healthcare Practitioners’ Understanding of the Zika Virus Disease

“…There is no known effective drug or vaccine available drug to fight against ZIKV. Patients infected with ZIKV are generally advised to rest and drink lots of water [22]. Treatment, if required, is mainly supportive, including intravenous fluids and antipyretics.…”

Green-Synthesized Mosquito Oviposition Attractants and Ovicides: Towards a Nanoparticle-Based “Lure and Kill” Approach?

“…Notably, AgNPs showed high oviposition attractiveness towards the three mosquito species (Tables 5, 6, 7). In latest years, a growing number of evidences have been provided about the larvicidal efficacy of plant-fabricated nanolarvicides, while only moderate efforts focused on their ovicidal potential and oviposition manipulation activity [17,36]. Each plant material containing unique bioactivity including repellent, larvicidal, ovicidal, and adulticidal activity, thus their efficacy of nanosynthetical routes varies from species to species and also according to the tested plant parts [1,2,37,38].…”

The human immune system’s response to carcinogenic and other infectious agents transmitted by mosquito vectors

“…Mosquitoes are well known for their ability to transmit deadly and debilitating pathogens and parasites, such as filariasis, malaria, WNV, chikungunya and increasingly dengue and Zika viruses (Benelli and Melhorn 2016). A comprehensive list of the main pathogens and parasites associated with mosquito vectors is available (see Murugan et al 2016).…”

“…This is not an easy task either, as illustated by several comprehensive reviews of the biological complexities involved in environmental mosquito control (Ferguson et al 2010;Benelli and Melhorn 2016;Webster et al 2016). The authors conclude that mosquitoes need to be controlled at multiple points in the continuum from egg to adult.…”