Bacterial Symbionts of the Triatominae and Their Potential Use in Control of Chagas Disease Transmission

Abstract

Chagas disease is caused by the parasitic protozoan Trypanosoma cruzi and transmitted by insects in the family Reduviidae, subfamily Triatominae, commonly known as kissing bugs. Because these insects feed throughout their entire developmental cycle on vertebrate blood, they harbor populations of symbiotic bacteria in their intestinal track that produce nutrients that are lacking in the insects' limited diet. It is possible to cultivate these bacteria, genetically modify them, and place them back into their insect host, thus generating a paratransgenic insect. This procedure has allowed the expression of antitrypanosomal gene products in the insect gut, thereby resulting in insects that are incapable of transmitting Chagas disease. A method has been developed that would allow introduction and spread of genetically modified symbionts into natural populations of kissing bugs, thus leading potentially to a transgenic intervention tool for use as a part of an integrated vector control approach.

Sylvatic foci of the Chagas disease vector Triatoma infestans in Chile: description of a new focus and challenges for control programs

“…Sylvatic triatomines may occasionally invade human residences, acting as founders of new colonies (Fitzpatrick et al 2008). Hence, it is necessary to study the ecology and behavior of their populations to understand the domiciliation process and generate new strategies for their control (Beard et al 2002, Guhl et al 2009, Moncayo & Silveira 2009). …”

Genetics and evolution of triatomines: from phylogeny to vector control

“…Genetic structure of populations Vector migration is important for genetic mixing, re-infestation following pesticide treatment, the spread of genetically modified symbionts (Beard et al, 2002) and pesticide resistance genes. Although adults generally fly poorly (for example, Barbu et al, 2010), some species have been known to fly as far as 1 km, and wingless nymphs can walk tens of meters (Nú ñez, 1987).…”

“…Typically, asymbiotic triatomines suffer important developmental delays, and increased mortality (Eichler and Schaub, 2002;Vallejo et al, 2009). A potential explanation is that triatomine blood meals lack essential vitamins and nutrients, which are supplied by symbionts (Beard et al, 2002). Microorganisms may thus influence the vector-parasite interaction through their relationships with both triatomines and trypanosomes.…”

“…For example, Rhodococcus rhodnii can be transformed so that it produces peptides of Lepidoptera (Beard et al, 1998;Beard et al, 2002) or a mammalian antibody (Durvasula et al, 1999) that strongly reduces the number of T. cruzi parasites in the vector. This parasite control strategy has been referred to as paratransgenesis, and may provide new options for Chagas disease control.…”

Characterization and control of symbiotic Bacillus cereus isolated from the mid gut of Anopheles subpictus Grassi

“…It was also well established that commensal microorganisms have positive impacts across a wide range of host physiology, including regulation of immunity and metabolism (Bäck-hed et al 2005;Round 2011). Microbial symbionts which use insects as their hosts can be controlled by natural agents (Mickes and Ferguson 1961;Beard et al 2002). Natural plant extracts are safe for human when compared to that of synthetic and chemical insecticides (Sharma 1993).…”