05. Chagas

Mayta, H., Romero, Y., Pando, A., Verastegui, M., Tinajeros, F., Bozo, R., Henderson-Frost, J., Colanzi, R., Flores, J., Lerner, R., Bern, C., Gilman, R.; Chagas Working Group in Perú and Bolivia.

PLoS Negl Trop Dis. 2019 Jan 11;13(1)

The detection of Trypanosoma cruzi genetic material in clinical samples is considered an important diagnostic tool for Chagas disease. We have previously demonstrated that PCR using clot samples yields greater sensitivity than either buffy coat or whole blood samples. However, phenol-chloroform DNA extraction from clot samples is difficult and toxic. The objective of the present study was to improve and develop a more sensitive method to recover parasite DNA from clot samples for the diagnosis of Chagas disease.

Levy MZ, Small DS, Vilhena DA, Bowman NM, Kawai V, Cornejo del Carpio JG, Cordova-Benzaquen E, Gilman RH, Bern C, Plotkin JB.

PLoS Comput Biol. 2011 Sep;7(9):e1002146.

Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease.

Bowman NM1, Kawai V, Gilman RH, Bocangel C, Galdos-Cardenas G, Cabrera L, Levy MZ, Cornejo del Carpio JG, Delgado F, Rosenthal L, Pinedo-Cancino VV, Steurer F, Seitz AE, Maguire JH, Bern C.

Am J Trop Med Hyg. 2011 Jan;84(1):85-90.

Chagas disease affects an estimated 8 million people in Latin America. Infected individuals have 20-30% lifetime risk of developing cardiomyopathy, but more subtle changes in autonomic responses may be more frequent. Electrocardiogram findings did not differ between cases and controls. However, compared with control children, infected children had blunted autonomic responses by three different measures, the Valsalva maneuver, the cold pressor test, and the orthostatic test. T. cruzi-infected children show autonomic dysfunction, although the prognostic value of this finding is not clear. Sustained vector control programs are essential to decreasing future T. cruzi infections.

Hidron AI, Gilman RH, Justiniano J, Blackstock AJ, Lafuente C, Selum W, Calderon M, Verastegui M, Ferrufino L, Valencia E, Tornheim JA, O’Neal S, Comer R, Galdos-Cardenas G, Bern C; Chagas Disease Working Group in Peru and Bolivia.

PLoS Negl Trop Dis. 2010 May 18;4(5):e688.

Patients with Chagas disease have migrated to cities, where obesity, hypertension and other cardiac risk factors are common. The study included adult patients evaluated by the cardiology service in a public hospital in Santa Cruz, Bolivia. Data included risk factors for T. cruzi infection, medical history, physical examination, electrocardiogram, echocardiogram, and contact 9 months after initial data collection to ascertain mortality.

Chagas cardiomyopathy remains an important cause of congestive heart failure in this hospital population, and should be evaluated in the context of the epidemiological transition that has increased risk of obesity, hypertension and chronic cardiovascular disease.

Bayer AM, Hunter GC, Gilman RH, Cornejo Del Carpio JG, Naquira C, Bern C, Levy MZ.

PLoS Negl Trop Dis. 2009 Dec 15;3(12)

Vectorborne transmission of Chagas disease has been historically rare in urban settings. However, in marginal communities near the city of Arequipa, Peru, urban transmission cycles have become established. We examined the history of migration and settlement patterns in these communities, and their connections to Chagas disease transmission. This was a qualitative study that employed focus group discussions and in-depth interviews. Five focus groups and 50 in-depth interviews were carried out with 94 community members from three shantytowns and two traditional towns near Arequipa, Peru. Focus groups utilized participatory methodologies to explore the community’s mobility patterns and the historical and current presence of triatomine vectors. In-depth interviews based on event history calendars explored participants’ migration patterns and experience with Chagas disease and vectors.

Levy MZ, Quíspe-Machaca VR, Ylla-Velasquez JL, Waller LA, Richards JM, Rath B, Borrini-Mayori K, del Carpio JG, Cordova-Benzaquen E, McKenzie FE, Wirtz RA, Maguire JH, Gilman RH, Bern C.

Am J Trop Med Hyg. 2008 Oct;79(4):528-34.

We used sentinel animal enclosures to measure the rate of infestation by the Chagas disease vector, Triatoma infestans, in an urban community of Arequipa, Peru, and to evaluate the effect of deltamethrin-impregnated netting on that rate. Impregnated netting decreased the rate of infestation of sentinel enclosures (rate ratio, 0.23; 95% confidence interval, 0.13-0.38; P < 0.001), controlling for the density of surrounding vector populations and the distance of these to the sentinel enclosures. Most migrant insects were early-stage nymphs, which are less likely to carry the parasitic agent of Chagas disease, Trypanosoma cruzi. Spread of the vector in the city therefore likely precedes spread of the parasite. Netting was particularly effective against adult insects and late-stage nymphs; taking into account population structure, netting decreased the reproductive value of migrant populations from 443.6 to 40.5. Impregnated netting can slow the spread of T. infestans and is a potentially valuable tool in the control of Chagas disease.