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Chagas disease in Mexico and Central America

R. prolixus appears to be exclusively associated with domestic environments in Central America and is thought to have been introduced from domestic South American populations, as has been demonstrated through morphometric and genetic comparisons of samples from Honduras and Colombia.80 The other two main species implicated in transmission in Central American countries are T. dimidiata and R. pallescens. T. dimidiata is endemic to the region and the most widespread vector species; it regularly invades domestic and peridomestic ecotypes from a variety of natural habitats including rock piles, palms, and caves.

It has been linked to rural and recently to urban transmission in Merida City, Yucatan, Mexico.81 R. pallescens occurs in Panama, where it is associated with Attelea palm trees and domestic infestations; recent reports demonstrate that TcI circulates in both domestic and sylvatic R. pallescens.82,83 Mexico has some 30 vector species (including T. dimidiata), with 8 that pose a risk to transmission.11 They are members of the Triatoma (Meccus) phyllosoma complex and Triatoma barberi (Fig. 5.2).

Table 5.1 Estimated demographic and epidemiological parameters of Chagas disease in Latin America by country

Latin American countries

Population

Estimated no. of people infected by T. cruzi

Estimated annual no. of new cases due to vectorial transmission

Estimated no. of women aged 15-44 years with T. cruzi infection

Estimated annual no. of cases of T. cruzi infection due to congenital transmission

Estimated prevalence of T. cruzi infection per 100 habitants

Estimated

incidence

due to

vectorial

transmission

per 100

habitants

Estimated incidence of T. cruzi infection due to congenital transmission per 100 live births

Estimated population at risk of T. cruzi infection

Estimated no. of people with Chagasic cardiopathy

Estimated

prevalence

of T. cruzi

infection

among

blood

donors

Argentina

41,343,000

1,505,235

1078

211,102

1457

3.640

0.0020

0.210

2,242,528

376,309

3.130

Belize

315,000

1040

10

272

25

0.330

0.0030

0.333

70,252

200

N/A

Bolivia

9,947,000

607,186

8087

199,351

616

6.104

0.0810

0.235

586,434

121,437

2.320

Brazil

190,755,799

1,156,821

46

119,298

571

0.03

0.084 per 1000-0.084

0.020

25,474,365

231,364

0.180

Chile

17,095,000

119,660

0

11,771

115

0.699

0

0.046

0

35,898

0.160

Colombia

45,805,000

437,960

5274

116,221

1046

0.956

0.0110

0.114

4,813,543

131,388

0.410

Costa Rica

4,516,000

7667

10

1728

61

0.169

0.0002

0.080

233,333

2300

0.045

Ecuador

14,483,499

199,872

2042

62,898

696

1.379

0.0140

0.317

4,199,793

40,384

0.190

El Salvador

6,952,000

90,222

972

18,211

234

1.297

0.0130

0.187

1,019,000

18,044

1.610

Guatemala

13,550,000

166,667

1275

32,759

164

1.230

0.0090

0.035

1,400,000

20,833

1.340

French Guyana

1,501,962

12,600

280

3818

18

0.838

0.0180

0.075

377,258

882

N/A

& Surinam

Honduras

7,989,000

73,333

933

16,149

257

0.917

0.0110

0.126

1,171,133

14,667

1.650

Mexico

112,468,855

876,458

6135

185,600

1788

0.779

0.0050

0.089

23,474,780

70,117

0.390

Nicaragua

5,604,000

29,300

383

5822

138

0.522

0.0060

0.124

642,750

5990

0.220

Panama

3,557,687

18,337

175

6332

40

0.515

0.0040

0.056

466,667

3667

0.500

Paraguay

8,668,000

184,669

297

63,385

525

2.130

0.0030

0.340

1,703,659

32,974

2.550

Peru

28,948,000

127,282

2055

28,132

232

0.439

0.0070

0.038

1,290,415

25,456

0.620

Uruguay

3,301,000

7852

0

1858

20

0.237

0

0.040

0

615

0.230

Venezuela

27,223,000

193,339

873

40,223

665

0.710

0.0030

0.110

1,033,450

38,668

0.320

(Bolivarian Republic of)

Total

543,877,115

5,742,167

29,925

1,124,930

8668

1.055

0.0050

0.089

70,199,360

1,171,193

0.930

As in northern South America, TcI predominates in Central America and Mexico in both sylvatic and domestic cycles. However, recent reports from Guatemala found domestic T. dimidiata harboring TcI and TcII concurrently.84 This surprising finding highlights a need for further molecular epidemiological studies in the region.

The Central American countries initiative (Belize, Costa Rica, El Salvador, Guatemala, Honduras, Panama) was inaugurated in 1996. This program, like the Central American countries, has more complications than the Southern Cone initiative because there are more vector species other than Rhodnius prolixus involved that maintain peridomestic habitats and pose the threat of reinvasion post control, such as Triatoma dimidiata.

 
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