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. 2014 May 22;8(5):e2894.
doi: 10.1371/journal.pntd.0002894. eCollection 2014.

Domestic animal hosts strongly influence human-feeding rates of the Chagas disease vector Triatoma infestans in Argentina

Ricardo E Gürtler  1 , María C Cecere  1 , Gonzalo M Vázquez-Prokopec  2 , Leonardo A Ceballos  1 , Juan M Gurevitz  1 , María Del Pilar Fernández  1 , Uriel Kitron  3 , Joel E Cohen  4
Affiliations

Domestic animal hosts strongly influence human-feeding rates of the Chagas disease vector Triatoma infestans in Argentina

Ricardo E Gürtler et al. PLoS Negl Trop Dis. .

Abstract

Background: The host species composition in a household and their relative availability affect the host-feeding choices of blood-sucking insects and parasite transmission risks. We investigated four hypotheses regarding factors that affect blood-feeding rates, proportion of human-fed bugs (human blood index), and daily human-feeding rates of Triatoma infestans, the main vector of Chagas disease.

Methods: A cross-sectional survey collected triatomines in human sleeping quarters (domiciles) of 49 of 270 rural houses in northwestern Argentina. We developed an improved way of estimating the human-feeding rate of domestic T. infestans populations. We fitted generalized linear mixed-effects models to a global model with six explanatory variables (chicken blood index, dog blood index, bug stage, numbers of human residents, bug abundance, and maximum temperature during the night preceding bug catch) and three response variables (daily blood-feeding rate, human blood index, and daily human-feeding rate). Coefficients were estimated via multimodel inference with model averaging.

Findings: Median blood-feeding intervals per late-stage bug were 4.1 days, with large variations among households. The main bloodmeal sources were humans (68%), chickens (22%), and dogs (9%). Blood-feeding rates decreased with increases in the chicken blood index. Both the human blood index and daily human-feeding rate decreased substantially with increasing proportions of chicken- or dog-fed bugs, or the presence of chickens indoors. Improved calculations estimated the mean daily human-feeding rate per late-stage bug at 0.231 (95% confidence interval, 0.157-0.305).

Conclusions and significance: Based on the changing availability of chickens in domiciles during spring-summer and the much larger infectivity of dogs compared with humans, we infer that the net effects of chickens in the presence of transmission-competent hosts may be more adequately described by zoopotentiation than by zooprophylaxis. Domestic animals in domiciles profoundly affect the host-feeding choices, human-vector contact rates and parasite transmission predicted by a model based on these estimates.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Temperature-adjusted proportion of domestic T. infestans that blood-fed the night before catch according to bug stage (A) and the chicken blood index (B).
Figueroa, October 2003 (spring). In B, each data point corresponds to a different house.
Figure 2
Figure 2. Percentage of late-stage T. infestans collected in human sleeping quarters that fed on each host species (regardless of feeding on other host species).
Figueroa, spring 2003. 95% confidence intervals clustered by site.
Figure 3
Figure 3. Proportion of late-stage domestic T. infestans that fed on humans (the human blood index) according to the proportion of bugs that fed on chickens (A) and dogs (B).
Each data point corresponds to a different house. The human and chicken blood indices include bugs that fed on humans or chickens, respectively, regardless of feeding on other species. Figueroa, October 2003 (spring).
Figure 4
Figure 4. Daily human-feeding rate of late-stage domestic T. infestans according to the proportion of chicken-fed bugs (A) and dog-fed bugs (B).
The daily human-feeding rate is the proportion of bugs that fed on humans only on the previous night. Figueroa, October 2003 (spring). Each data point corresponds to a different house.
See this image and copyright information in PMC

References

    1. Lehane MJ (2005) The biology of blood-sucking in insects, 2nd ed. Cambridge: Cambridge University Press.
    1. Gürtler RE, Cohen JE, Cecere MC, Chuit R (1997) Shifting host choices of the vector of Chagas disease Triatoma infestans in relation to the availability of hosts in houses in north-west Argentina. J Appl Ecol 34: 699–715.
    1. Basáñez MG, Razali K, Renz A, Kelly D (2007) Density-dependent host choice by disease vectors: epidemiological implications of the ideal free distribution. Trans R Soc Trop Med Hyg 101: 256–269. - PubMed
    1. Anderson RM, May RM (1991) Infectious diseases of humans. Oxford: Oxford University Press.
    1. Dye C (1992) The analysis of parasite transmission by bloodsucking insects. Annu Rev Entomol 37: 1–19. - PubMed

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