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Effect of repeat human blood feeding on Wolbachia density and dengue virus infection in Aedes aegypti.

Amuzu HE, Simmons CP, McGraw EA - Parasit Vectors (2015)

Bottom Line: The Wolbachia infected Aedes aegypti mosquito line was used for the study.All groups were orally infected with DENV-2 and then their midguts and salivary glands were dissected 10-11 days post infection.RNA/DNA was simultaneously extracted from each tissue and subsequently used for DENV RNA copies and Wolbachia density quantification, respectively.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Monash University, Clayton, Melbourne, Victoria, Australia. hilaria.amuzu@monash.edu.

ABSTRACT

Background: The introduction of the endosymbiotic bacterium, Wolbachia into Aedes aegypti populations is a novel approach to reduce disease transmission. The presence of Wolbachia limits the ability of the mosquito to transmit dengue virus (DENV) and the strength of this effect appears to correlate with Wolbachia densities in the mosquito. There is also some evidence that Wolbachia densities may increase following the consumption of a bloodmeal. Here we have examined whether multiple blood feeds lead to increases in density or associated changes in Wolbachia-mediated blocking of DENV.

Methods: The Wolbachia infected Aedes aegypti mosquito line was used for the study. There were three treatment groups; a non-blood fed control, a second group fed once and a third group fed twice on human blood. All groups were orally infected with DENV-2 and then their midguts and salivary glands were dissected 10-11 days post infection. RNA/DNA was simultaneously extracted from each tissue and subsequently used for DENV RNA copies and Wolbachia density quantification, respectively.

Results: We found variation between replicate vector competence experiments and no clear evidence that Wolbachia numbers increased in either the salivary glands or remainder of the body with feeding and hence saw no corresponding improvements in DENV blocking.

Conclusions: Aedes aegypti are "sip" feeders returning often to obtain bloodmeals and hence it is important to assess whether repeat blood feeding improved the efficacy of Wolbachia-based DENV blocking. Our work suggests in the laboratory context when Wolbachia densities are high that repeat feeding does not improve blocking and hence this ability should likely be stable with respect to feeding cycle in the field.

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Related in: MedlinePlus

Wolbachia density in salivary gland, midgut and body of wMel.F mosquitoes. Significantly more Wolbachia was found in the remainder of the mosquito body compared to the salivary glands and midguts (P < 0.0001). Salivary glands had significantly more Wolbachia than the midguts (P = 0.0009). Y-axis shows ratio of wsp/Rps17. Letters denote distinct statistical groups and error bars are standard error of the mean of 16–17 biological replicates.
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Fig1: Wolbachia density in salivary gland, midgut and body of wMel.F mosquitoes. Significantly more Wolbachia was found in the remainder of the mosquito body compared to the salivary glands and midguts (P < 0.0001). Salivary glands had significantly more Wolbachia than the midguts (P = 0.0009). Y-axis shows ratio of wsp/Rps17. Letters denote distinct statistical groups and error bars are standard error of the mean of 16–17 biological replicates.

Mentions: The Wolbachia densities were significantly different in the tissues examined. The midgut had the lowest Wolbachia density and was 2.43-2.5 fold lower than that of salivary glands. The mosquito body had the highest density and was 3.3-5.3 fold higher than that of salivary glands and 7.9-13 fold higher than that of the midgut (Figure 1). The body included the ovaries and therefore was expected to have higher densities of Wolbachia. These findings are consistent with previously published characterisations of the wAlbB and wAlbA strains present in Ae. albopictus and the wAlbB strain stably transinfected into Ae. aegypti [20].Figure 1


Effect of repeat human blood feeding on Wolbachia density and dengue virus infection in Aedes aegypti.

Amuzu HE, Simmons CP, McGraw EA - Parasit Vectors (2015)

Wolbachia density in salivary gland, midgut and body of wMel.F mosquitoes. Significantly more Wolbachia was found in the remainder of the mosquito body compared to the salivary glands and midguts (P < 0.0001). Salivary glands had significantly more Wolbachia than the midguts (P = 0.0009). Y-axis shows ratio of wsp/Rps17. Letters denote distinct statistical groups and error bars are standard error of the mean of 16–17 biological replicates.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4413987&req=5

Fig1: Wolbachia density in salivary gland, midgut and body of wMel.F mosquitoes. Significantly more Wolbachia was found in the remainder of the mosquito body compared to the salivary glands and midguts (P < 0.0001). Salivary glands had significantly more Wolbachia than the midguts (P = 0.0009). Y-axis shows ratio of wsp/Rps17. Letters denote distinct statistical groups and error bars are standard error of the mean of 16–17 biological replicates.
Mentions: The Wolbachia densities were significantly different in the tissues examined. The midgut had the lowest Wolbachia density and was 2.43-2.5 fold lower than that of salivary glands. The mosquito body had the highest density and was 3.3-5.3 fold higher than that of salivary glands and 7.9-13 fold higher than that of the midgut (Figure 1). The body included the ovaries and therefore was expected to have higher densities of Wolbachia. These findings are consistent with previously published characterisations of the wAlbB and wAlbA strains present in Ae. albopictus and the wAlbB strain stably transinfected into Ae. aegypti [20].Figure 1

Bottom Line: The Wolbachia infected Aedes aegypti mosquito line was used for the study.All groups were orally infected with DENV-2 and then their midguts and salivary glands were dissected 10-11 days post infection.RNA/DNA was simultaneously extracted from each tissue and subsequently used for DENV RNA copies and Wolbachia density quantification, respectively.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Monash University, Clayton, Melbourne, Victoria, Australia. hilaria.amuzu@monash.edu.

ABSTRACT

Background: The introduction of the endosymbiotic bacterium, Wolbachia into Aedes aegypti populations is a novel approach to reduce disease transmission. The presence of Wolbachia limits the ability of the mosquito to transmit dengue virus (DENV) and the strength of this effect appears to correlate with Wolbachia densities in the mosquito. There is also some evidence that Wolbachia densities may increase following the consumption of a bloodmeal. Here we have examined whether multiple blood feeds lead to increases in density or associated changes in Wolbachia-mediated blocking of DENV.

Methods: The Wolbachia infected Aedes aegypti mosquito line was used for the study. There were three treatment groups; a non-blood fed control, a second group fed once and a third group fed twice on human blood. All groups were orally infected with DENV-2 and then their midguts and salivary glands were dissected 10-11 days post infection. RNA/DNA was simultaneously extracted from each tissue and subsequently used for DENV RNA copies and Wolbachia density quantification, respectively.

Results: We found variation between replicate vector competence experiments and no clear evidence that Wolbachia numbers increased in either the salivary glands or remainder of the body with feeding and hence saw no corresponding improvements in DENV blocking.

Conclusions: Aedes aegypti are "sip" feeders returning often to obtain bloodmeals and hence it is important to assess whether repeat blood feeding improved the efficacy of Wolbachia-based DENV blocking. Our work suggests in the laboratory context when Wolbachia densities are high that repeat feeding does not improve blocking and hence this ability should likely be stable with respect to feeding cycle in the field.

Show MeSH
Related in: MedlinePlus