Chagas’ Disease: An Emergent Urban Zoonosis. The Caracas Valley (Venezuela) as an Epidemiological Model

Abstract

The unprecedented emergence of important public health and veterinary zoonoses is usually a result of exponential population growth and globalization of human activities. I characterized Chagas’ disease as an emergent zoonosis in the Caracas Valley (Venezuela) due to the following findings: the presence of reservoirs (Didelphis marsupialis, Rattus rattus) and vectors (Panstrongylus geniculatus, Panstrongylus rufotuberculatus) infected with Trypanosoma cruzi in urbanized or marginalized areas; the elevated contact between P. geniculatus and human beings detected by parasitological and molecular examinations of triatomine feces demonstrated the possibility of transmission risks; a study of outbreaks of urban Chagas’ disease reported the first proven case of oral transmission of T. cruzi to human beings; the risk of transmission of glandular metacyclic stages from marsupials by experimental ocular and oral instillation; mice genitalia infected with T. cruzi contaminated blood resulted in the formation of amastigotes very close to the lumen suggesting that there may be a possibility of infection via their release into the urine and thence to the exterior; the ubiquitous histotropism and histopathology of T. cruzi was demonstrated using a mouse model; the presence of experimental T. cruzi pseudocysts in adipose, bone-cartilage, and eye tissue indicated a potential risk for transplants. Socio-sanitary programs that include improvements in housing, vector control, and access to medical treatment, as well as strategies aimed at combating social inequalities, poverty, and underdevelopment should be undertaken in those areas where zoonoses are most prevalent. Disciplines, such as Ecology, Epidemiology, Medical Entomology, Human and Veterinary Medicine, Environmental Studies, Public Health, Social and Political Studies, Immunology, Microbiology, and Pharmacology could all provide important contributions that aim to reduce the occurrence of factors governing the spread of emergent diseases.

Acute Chagas disease in the state of Pará, Amazon Region: is it increasing?

“…This finding suggests that the urban area has a larger number of inhabitants who consume açaí on a daily basis. It may also be related to the fact that in the urban area, the diagnosis and active surveillance of cases are conducted better ( Pickenhayn et al 2008 , Urdaneta-Morales 2014 , Alroy et al 2015 ).…”

Urban Trypanosoma cruzi Oral Transmission: from a Zoonotic Founder Focus to the Largest Microepidemic of Chagas Disease

“…On the hill Waraira Repano (also known as Cerro El Ávila), very close to the focus studied, all the elements of the sylvatic cycle of T. cruzi, like "armadillos", and other small mammals are present, being the Didelphis marsupialis, a Caracas valley synanthropic reservoir, one of the most common, [5,16] with an important role in the transmission cycle in the capital city. However, the area's inhabitants did not report its presence and in the study of triatomines, it is not present as blood source, which suggests the participation of other mammals.…”

Host Diversity and Origin of Zoonoses: The Ancient and the New

“…Chagas disease is an example of a successful parasitic zoonosis with a wide range (hundreds) of mammal species hosts in South America, transmitted by dozens of triatomine bug species (Table 1). Known as American trypanosomiasis, it also owes its name to Carlos Chagas, a Brazilian researcher who first described it in Brazil in 1909 as a disease due to the parasite Trypanosoma cruzi (named after Oswaldo Cruz, another Brazilian scientist), later shown to parasitize species of mammals from seven "orders" and triatomines from 15 genera [23]. A comprehensive study of reservoirs and wild hosts of T. cruzi.…”