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Mosquitoes, Blackflies & Ticks (click here for publications in PDF format)

Aedes aegypti transmits dengue, chikungunya and Zika virus

The control of blood-sucking insects that transmit human and animal diseases remains a major challenge in many parts of the world, particularly in developing countries.

My work on mosquitoes (Aedes aegypti) and blackflies (Simulium spp.) has primarily focused on their relationships with viral pathogens (see section on iridescent viruses) or control using a naturally-derived insecticide (see section on spinosad).  I briefly collaborated in studies on saliva activated transmission of viruses by ticks.

I also became interested in habitat manipulation for control of Anopheles pseudopunctipennis, a vector of malaria in southern Mexico.  This work was performed by Guillermo Bond.
 

In Mexico, and many other parts of Latin America, the immature stages of An. pseudopunctipennis develop in river pools abundant in filamentous green algae (Spirogyra and Cladophora).
 

The algae represent an important food source and provide a refuge from predators for the mosquito larvae.

This relationship has been described in detail by Bond et al. (2005).
 

As a result, ovipositing females select habitats based on the presence of these algae.
 

Extraction of algae from these pools results in a marked decrease in the densities of larvae and adult mosquitoes that lasts for 6 – 8 weeks.
 

This effectively eliminates the mosquito population during the period of peak biting activity of this species in southern Mexico (Bond et al. 2004).
 

For its simplicity and effectiveness, the intervention has now been incorporated into the Mexican Government’s Health Department guidelines on Epidemiological Monitoring, Prevention and Control (NOM-032-SSA2-2002). Importantly, the intervention can be performed by local communities in affected areas.

Studies on the environmental impact of the intervention have concluded that algal extraction results in minor changes in the diversity of aquatic insect communities (Bond et al. 2006).

Treated areas fully recover their insect diversity in 3-4 months. Indeed, the magnitude of these changes is much lower than the natural (stochastic) variation in the aquatic community caused by year-to-year variation in rainfall and river discharge.
 

Filamentous algae form floating mats in riverside pools: ideal for the development of Anopheles mosquitoes.

Extraction of filamentous algae results in a dramatic reduction in Anopheles mosquito populations.

Loading sterile male mosquitoes into a drone fitted with a mosquito release device in Chiapas, Mexico.

In an on-going collaboration with Drs. Guillermo Bond and Carlos Marina (CRISP-INSP) and researchers in ECOSUR, the efficacy of the sterile insect technique is being evaluated as a method for control of two species of mosquito that are the principal vectors of dengue in Mexico.

For this, large numbers of male mosquitoes have to be reared, sterilized using a radiation source and released into the environment.

Wild females that mate with sterilized males will not be able to produce offspring, resulting in a rapid decrease in the mosquito population.

Recent trials compared the efficiency of ground-based release and drone-mediated release of many thousands of sterile males in a rural zone of southern Chiapas

This study was published by Marina et al. (2022).

Click here for publications on arthropod vectors
 

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