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Ur=
ban
Chagas Disease
•
•T=
he New
Urban Habitat for Chagas Disease
•(=
American
Trypanosomiasis) in the US:
•
•I=
nfluences
of Climatic, Behavioral, and Demographic Factors
•
•
•
•Diaz J,
Claiborne C, Mischler P, Nieto P, Dorn P, Malone J
•
•
•LSU Sch=
ools
of Public Health and Veterinary Medicine,
•and Loy=
ola
University-New Orleans
•New Orl=
eans
& Baton Rouge, Louisiana
•
Urban
Chagas
Outline<= /b>
Outline<= /b>
1.Introduction
=
2.Epidemiology
=
3.Arthropod
vectors
4.Animal
reservoirs
5.Life cycle and hu=
man transmission
6.Rural-to-urban ecology
7.Clinical <=
span
style=3D'position:absolute;top:49.75%;left:57.67%;width:34.08%;height:6.0%=
'>manifestations
8.Methods
9.Results
10.Conclusions
=
;
11.
Urban
Chagas
Introduction=
Introduction=
•<=
u>Definition
• Chagas disease, or American=
trypanosomiasis, is a zoonotic infectious disease caused by the kinetoplastid (Subclass Kinetoplastidae) protozoan, Trypanosoma cruzi=
, & transmitted to man by local reduviid bugs (Family <=
span
style=3D'position:absolute;top:64.0%;left:4.68%;width:50.18%;height:5.25%'=
>Reduviidae, & Subfamily Triatominae) of several species. I=
n the Americas, Chagas disease shares =
many transmission features with other infectious diseases including =
malaria, plague, and yellow fever.
•
Common Latin American =
Reduviid Bug:
•<=
u>Triatoma
infestans
•
![](3D"slide0019_image002.jpg")
Urban
Chagas
Epidemiology=
Epidemiology=
Burden of disease
=
1.Chagas
disease is the 2nd most c=
ommon
cause of death from
parasitic diseases in the Americas,
next to malaria.
2.1/5
of Latin America’s population
(or 90 million person=
s) are
at risk of contracting Chagas
disease.
3.20+
million persons in the Americas
are now seropositive for
Chagas.
=
=
=
=
•<=
u>Chronic
disease epidemiology
1.70-80% of Chagas-infected persons remain subclinically seropositive, unless immuno-compromised, often by HIV.
2.Indeterminate (latent) Chagas exists in 20+ M persons, 2.5-6 M of whom will develop Chagas.
3.200,000+ seropositive persons, capable of transmitting Chagas by reduviid bites, transfusion, or organ donation live in the US.
=
4.
Chagas Vectors: Triatomines=
1.
•Family: Reduviidae, Subfamily: Triatominae-assassin, cone-nose, or, more commonly, face-biting “kissing” bugs. Genera=
: Triatoma, Rhodnius,
& Panstrongylus
spp.
•Adults:1-2 inch long lar=
ge
bugs; long snout & dark =
eyes;
4-segment antennae; thin,
straight, & retrac=
table
proboscis; triangular thorax,
folding wings-contrasting dark
(br=
own-orange) & light (yellow-pink<=
/span>) colors. Adults are powerful flyers, but often prefer walking. Like nymphs.
•Nymp=
hs: do not fly & mature over 5 blood-feeding instar stages. All stages are infective for life.
Adult Triatoma spp., note retractable proboscis
![](3D"slide0012_image004.gif")
![](3D"slide0012_image006.gif")
Chagas Vectors: Triatomines
2.
Chagas Vectors: Triatomines
3.
•Triatoma infestans
•Triatoma gerstaeckeri
![](3D"slide0033_image007.jpg")
![](3D"slide0033_image009.jpg")
Chagas Vectors: Triatomines 4.<=
/u>
•Eggs: 200-300 white-to-p=
inkish
oval eggs with constri=
cted
neck just before operculum
deposited in cracks=
&
crevices in adobe-mud walls =
&
floors, & thatched roofs.
•Nymphs: emerge after 15-=
30
days, small & pale,
resemble adults, but cannot=
fly,
5 instars-all voracious nocturnal
blood-feeders & all can transmit
Trypanosoma cruzi- triatomine
infection rates in Latin America
are 25-60% vs. 20% in US.
•Triatomine
•eggs
•
•
•
•Control: interior sprayi=
ng of residual insecticides-OPs > pyrethroids > OCs. OP-impregnated interior paints.
•Prevention: plaster or <=
/span>sheetrock interior walls, replace mud-sealed walls with bricks/concrete blocks =
to eliminate cracks; replace thatched roofs with corrugated metal roofs.
•
![](3D"slide0013_image011.gif")
Chagas Animal Reservoirs 1.
Latin America
1.Wild
animal reservoirs: armadi=
llos,
marsupials, monkeys, opossums=
, rodents, sloths.
2.Domestic
animal reservoirs (T. cruzi infection rate): dogs (≤ 80%), cats (≤ 60%), guinea pigs (≤ 60%), rabbits (≤ 60%), sheep (≤ 19%),&nb=
sp;
goats (≤ 9%). &nb=
sp;
1.Wild
animal reservoirs (T. cruzi
infection rate): armad=
illos
(≥ 20%), oposs=
ums,
raccoons (30-40%),
rodents, squirrels.
2.Domestic
animal reservoirs (T. cruzi =
infection rate): outdoor-kenneled dogs (4-50%).
![](3D"slide0021_image013.jpg")
![](3D"slide0021_image015.jpg")
Chagas Animal Reservoirs 2.
=
=
Preferred
wild reservoir: Armadillos
=
Preferred
wild reservoir: Opossums=
![](3D"slide0035_image016.jpg")
![](3D"slide0035_image017.jpg")
C=
hagas:
T. cruzi=
Life Cycle: Bug
![](3D"slide0023_image019.jpg")
Ch=
agas: T. cruzi Life Cycle: Man (1-5)
![](3D"slide0036_image021.jpg")