Space Grant Consortium - University of Wisconsin - Green Bay

group started in 1997 with the goal of eliminating vectorial Chagas disease transmission from its
region by 2010 (Guhl, 2007). One of the biggest challenges is coordinating governmental efforts
to s ystematically c ontrol t he ve ctors; w ithout t horough control efforts, r einfestation is lik ely,
especially when homes are close in proximity. P roximity is considered an important factor not
only in bugs spreading from one home to another, but also in determining which host species a
triatomine chooses to bite (Minter, 1976a).
Because of Chagas disease’s complex epidemiology, it is important to carefully examine
all potential risk factors; I have focused on the environmental factors that affect risk. T he host
species t hat pr ovide bl ood m eals f or t riatomines a re a n i mportant c omponent of t he C hagas
disease transmission. T. infestans feeds on a variety of mammals and birds, but birds cannot be
infected b y t he T. cruzi parasite, s o t hey pl ay a uni que role i n C hagas disease ep idemiology.
Research i n t he C haco region o f northern Argentina ha s s uggested t hat during hot w eather T.
infestans prefer feeding on c hickens and dogs over humans when all are present (Gürtler et al.,
1997). Dogs and cats also are significantly more infectious to bugs compared to humans making
them important reservoir sources of T. cruzi infection (Gürtler et al., 2007). B ecause of guinea
pigs’ abundance a nd hi gh i nfectivity o f T. cruzi, they occupy a c rucial r ole i n t he C hagas
epidemiology i n B olivia a nd P eru ( Minter, 1976b). Sheep h ave a T. cruzi seroprevalence o f
approximately 19% ( Cetron, 1995) . C attle, pi gs, a nd ot her large livestock ha ve m uch l ower
infectivities to T. cruzi, and l ess research ha s focused on t heir r ole i n transmission (Minter,
1976a). However, the importance of pigs in Chagas disease transmission has been suggested by
Pizarro and Stevens’ study of T. infestans in Bolivia (2008). Studying the factors of host animal
competence t o T. cruzi, T. infestans animal pr eference, a nd hos t be havior i s i mportant f or
understanding the role of animals in Chagas disease transmission to humans.
Survey d ata f rom a p eri-urban c ommunity of Arequipa, P eru a llows one to ex amine
explanatory v ariables o f hous ehold i nfestation o f T. infestans, a likely measure o f t he r isk o f
contracting C hagas d isease. W hile s ome Latin A merican c ountries ha ve ha d s uccessful
insecticide c ampaigns to e liminate th e T. infestans vector, s outhern P eru s till ha s T. infestans
vector presence, which is conducive for analyzing spatial patterns of infestation (Fraser, 2008).
Arequipa may be representative for other dry areas such as the arid Chaco region of Argentina
where the T. infestans vector is also present. Examining type and number of household animals
in conjunction with socio-economic indicators such as housing type in a spatial analysis allows
us to explain why certain houses are more susceptible to infestation than others.
Methods and Materials
Study Area
The s tudy was c arried out i n N ueva A lborada (Figure 1 ), a pe ri-urban c ommunity of
Arequipa, Peru, located at 16.433˚S, -71.492˚W (Levy et al., 2008).
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