Mosquito aquatic habitat modification and manipulation interventions to control malaria

Area of Science:

• Public Health
• Infectious Disease Epidemiology
• Vector-Borne Disease Control

Background:

• Larval source management (LSM) encompasses strategies like habitat modification and manipulation to reduce mosquito breeding sites, aiming to decrease Plasmodium parasite transmission in malaria-endemic regions.
• This review is an update of a 2013 publication, examining the effectiveness of LSM approaches, with or without larviciding, for malaria control.

Purpose of the Study:

• To systematically describe and summarize interventions involving mosquito aquatic habitat modification or manipulation for malaria control.
• To evaluate the beneficial and adverse effects of these aquatic habitat interventions on malaria control.

Main Methods:

• A comprehensive Cochrane search was conducted, covering literature from January 2012 to November 2021.
• Included studies were randomized controlled trials (RCTs) and non-randomized intervention studies comparing habitat modification/manipulation to control groups.
• Primary outcomes included clinical malaria incidence, malaria parasite prevalence, and parasitaemia incidence, analyzed using narrative synthesis and assessed with GRADE methodology.

Main Results:

• Sixteen studies (RCTs, controlled before-after, non-randomized controlled) were included, primarily from Africa and Asia.
• Habitat manipulation showed mixed results for entomological outcomes; some methods like spillways and faster water drawdown may reduce immature mosquito densities, but effects on malaria prevalence are uncertain.
• Combined habitat modification and manipulation, with or without larviciding, demonstrated potential reductions in adult and immature mosquito densities, though evidence for impact on malaria parasite prevalence was often of low to very low certainty.

Conclusions:

• Habitat modification and manipulation interventions show some promise for reducing malaria through both epidemiological and entomological outcomes.
• The evidence base is mixed, and further research is necessary to enhance understanding and confirm the utility of these varied malaria control approaches in specific contexts.