scholarly journals Elucidating the mechanism of Trypanosoma cruzi acquisition by triatomine insects: evidence from a large field survey of Triatoma infestans

2020 ◽  
Author(s):  
Aaron W. Tustin ◽  
Ricardo Castillo-Neyra ◽  
Laura D. Tamayo ◽  
Katty Borini-Mayorí ◽  
Renzo Salazar ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Control Strategies ◽  
Protozoan Parasite ◽  
Etiologic Agent ◽  
Triatoma Infestans ◽  
Large Field ◽  
Infection Prevalence ◽  
Percentage Points ◽  
Blood Sucking ◽  
Triatomine Bugs

AbstractBlood-sucking triatomine bugs transmit the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease. We measured the prevalence of T. cruzi infection in 58,519 Triatoma infestans captured in residences in and near Arequipa, Peru. Among bugs from infected colonies, T. cruzi prevalence increased with stage from 12% in second instars to 36% in adults. Regression models demonstrated a linear relationship between infection prevalence and developmental stage. Prevalence increased by 5.4 percentage points with each additional stage. We postulate that the probability of acquiring the parasite may be related to the number of feeding events. Transmission of the parasite does not appear to be correlated with the amount of blood ingested during feeding. Similarly, other hypothesized transmission routes such as coprophagy fail to explain the observed pattern of prevalence. Our results could have implications for the feasibility of late-acting control strategies that preferentially kill older insects.

scholarly journals Elucidating the Mechanism of Trypanosoma cruzi Acquisition by Triatomine Insects: Evidence from a Large Field Survey of Triatoma infestans

2020 ◽  
Vol 5 (2) ◽  
pp. 87
Author(s):  
Aaron W. Tustin ◽  
Ricardo Castillo-Neyra ◽  
Laura D. Tamayo ◽  
Renzo Salazar ◽  
Katty Borini-Mayorí ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Regression Models ◽  
Control Strategies ◽  
Protozoan Parasite ◽  
Etiologic Agent ◽  
Triatoma Infestans ◽  
Large Field ◽  
Blood Sucking ◽  
Triatomine Bugs ◽  
Cruzi Infection

Blood-sucking triatomine bugs transmit the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease. We measured the prevalence of T. cruzi infection in 58,519 Triatoma infestans captured in residences in and near Arequipa, Peru. Among bugs from infected colonies, T. cruzi prevalence increased with stage from 12% in second instars to 36% in adults. Regression models demonstrated that the probability of parasite acquisition was roughly the same for each developmental stage. Prevalence increased by 5.9% with each additional stage. We postulate that the probability of acquiring the parasite may be related to the number of feeding events. Transmission of the parasite does not appear to be correlated with the amount of blood ingested during feeding. Similarly, other hypothesized transmission routes such as coprophagy fail to explain the observed pattern of prevalence. Our results could have implications for the feasibility of late-acting control strategies that preferentially kill older insects.

scholarly journals Hosts and vectors of Trypanosoma cruzi discrete typing units in the Chagas disease endemic region of the Paraguayan Chaco

Parasitology ◽  
2017 ◽  
Vol 144 (7) ◽  
pp. 884-898 ◽  
Author(s):  
NIDIA ACOSTA ◽  
ELSA LÓPEZ ◽  
MICHAEL D. LEWIS ◽  
MARTIN S. LLEWELLYN ◽  
ANA GÓMEZ ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Control Strategies ◽  
Triatoma Infestans ◽  
Effective Control ◽  
Primary Role ◽  
Endemic Region ◽  
Triatomine Bugs ◽  
Chaco Region ◽  
Euphractus Sexcinctus

SUMMARYActive Trypanosoma cruzi transmission persists in the Gran Chaco region, which is considered hyperendemic for Chagas disease. Understanding domestic and sylvatic transmission cycles and therefore the relationship between vectors and mammalian hosts is crucial to designing and implementing improved effective control strategies. Here we describe the species of triatomine vectors and the sylvatic mammal reservoirs of T. cruzi, in different localities of the Paraguayan and Bolivian Chaco. We identify the T. cruzi genotypes discrete typing units (DTUs) and provide a map of their geographical distribution. A total of 1044 triatomines and 138 sylvatic mammals were captured. Five per cent of the triatomines were microscopically positive for T. cruzi (55 Triatoma infestans from Paraguay and one sylvatic Triatoma guasayana from Bolivia) and 17 animals (12·3%) comprising eight of 28 (28·5%) Dasypus novemcinctus, four of 27 (14·8%) Euphractus sexcinctus, three of 64 (4·7%) Chaetophractus spp. and two of 14 (14·3%) Didelphis albiventris. The most common DTU infecting domestic triatomine bugs was TcV (64%), followed by TcVI (28%), TcII (6·5%) and TcIII (1·5%). TcIII was overwhelmingly associated with armadillo species. We confirm the primary role of T. infestans in domestic transmission, armadillo species as the principal sylvatic hosts of TcIII, and consider the potential risk of TcIII as an agent of Chagas disease in the Chaco.

scholarly journals Investigation regarding the presence of Trypanosoma cruzi in triatomines and humans in rural households in the State of Paraná, southern Brazil

2021 ◽  
Vol 10 (10) ◽  
pp. e54101018366
Author(s):  
Ana Paula de Abreu ◽  
Hevillyn Fernanda Lucas da Silva ◽  
Marcella Paula Mansano Sarto ◽  
Giullia Ferreira Iunklaus ◽  
João Vitor Trovo ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Rural Households ◽  
Etiologic Agent ◽  
The State ◽  
Molecular Techniques ◽  
Triatoma Infestans ◽  
Southern Brazil ◽  
The North ◽  
Intestinal Contents ◽  
Cruzi Infection

Trypanosoma cruzi, the etiologic agent of Chagas disease (CD), is transmitted by hematophagous insects belonging to the subfamily Triatominae. After elimination of Triatoma infestans, the infestation of human dwellings by secondary species of vectors continues to pose a risk of transmission of the parasite. Our aim was to investigate the T. cruzi presence in triatomines and humans in rural households in the State of Paraná, southern Brazil. The capture of the insects was carried out by technicians of the municipalities after residents reported the outbreak. Five residents and 27 triatomines captured in four municipalities in the North and Midwest of the state were evaluated. The research of T. cruzi was carried out using parasitological, serological, and molecular techniques, in human blood, excreta, intestinal contents and insect macerate. Panstrongylus megistus, P. geniculatus and Triatoma sp.  were identified. Ten specimens of P. megistus were captured in a house in Mandaguari with five residents and presented an infection rate of 70% for T. cruzi like. All residents tested negative for T. cruzi infection. Another 15 P. megistus were captured in the peridomicile in Janiópolis and had 100.0% positivity. The only adult specimen of P. geniculatus captured in the intradomicile in Amaporã, as well as the nymph of Triatoma in the peridomicile in Paiçandu, were negative. The finding of P. megistus naturally infected by T. cruzi in households in rural area of Paraná demonstrates a potential risk of vector transmission of CD in these regions.

Trypanosoma cruzi Infection Prevalence and Bloodmeal Analysis in Triatomine Vectors of Chagas Disease From Rural Peridomestic Locations in Texas, 2013–2014

2016 ◽  
Vol 53 (4) ◽  
pp. 911-918 ◽  
Author(s):  
Rodion Gorchakov ◽  
Lillian P. Trosclair ◽  
Edward J. Wozniak ◽  
Patricia T. Feria ◽  
Melissa N. Garcia ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Disease Surveillance ◽  
Public Awareness ◽  
Parasite Burden ◽  
Etiologic Agent ◽  
Infection Prevalence ◽  
Transmission Cycle ◽  
High Infection ◽  
History Of

Abstract Protozoan pathogen Trypanosoma cruzi (Chagas, 1909) is the etiologic agent of Chagas disease, which affects millions of people in Latin America. Recently, the disease has been gaining attention in Texas and the southern United States. Transmission cycle of the parasite involves alternating infection between insect vectors and vertebrate hosts (including humans, wildlife, and domestic animals). To evaluate vector T. cruzi parasite burden and feeding patterns, we tested triatomine vectors from 23 central, southern, and northeastern counties of Texas. Out of the 68 submitted specimens, the majority were genetically identified as Triatoma gerstaeckeri (Stal, 1859), with a few samples of Triatoma sanguisuga (LeConte, 1855), Triatoma lecticularia (Stal, 1859), Triatoma rubida (Uhler, 1894), and Triatoma protracta woodi (Usinger, 1939). We found almost two-thirds of the submitted insects were polymerase chain reaction-positive for T. cruzi. Bloodmeal sources were determined for most of the insects, and 16 different species of mammals were identified as hosts. The most prevalent type of bloodmeal was human, with over half of these insects found to be positive for T. cruzi. High infection rate of the triatomine vectors combined with high incidence of feeding on humans highlight the importance of Chagas disease surveillance in Texas. With our previous findings of autochthonous transmission of Chagas disease, urgent measures are needed to increase public awareness, vector control in and around homes, and Chagas screening of residents who present with a history of a triatomine exposure.

scholarly journals Trypanosoma cruzi infection in Triatoma infestans and high levels of human–vector contact across a rural-to-urban gradient in the Argentine Chaco

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alejandra Alvedro ◽  
María Sol Gaspe ◽  
Hannah Milbourn ◽  
Natalia Paula Macchiaverna ◽  
Mariano Alberto Laiño ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Rural Areas ◽  
Control Strategies ◽  
Blood Feeding ◽  
Urban Setting ◽  
Transmission Risk ◽  
Triatoma Infestans ◽  
Urban Gradient ◽  
Urban Settings ◽  
Feeding Sources

Abstract Background Peri-urban and urban settings have recently gained more prominence in studies on vector-borne transmission of Trypanosoma cruzi due to sustained rural-to-urban migrations and reports of urban infestations with triatomines. Prompted by the finding of Triatoma infestans across the rural-to-urban gradient in Avia Terai, an endemic municipality of the Argentine Chaco, we assessed selected components of domestic transmission risk in order to determine its variation across the gradient. Methods A baseline vector survey was conducted between October 2015 and March 2016, following which we used multistage random sampling to select a representative sample of T. infestans at the municipal level. We assessed T. cruzi infection and blood-feeding sources of 561 insects collected from 109 houses using kinetoplast DNA-PCR assays and direct enzyme-linked immunosorbent assays, respectively. We stratified triatomines according to their collection site (domestic or peridomestic), and we further categorized peridomestic sites in ecotopes of low- or high-risk for T. cruzi infection. Results The overall adjusted prevalence of T. cruzi-infected T. infestans was 1.8% (95% confidence interval [CI] 1.3–2.3) and did not differ between peri-urban (1.7%) and rural (2.2%) environments. No infection was detected in bugs captured in the urban setting; rather, infected triatomines were mainly collected in rural and peri-urban domiciles, occurring in 8% of T. infestans-infested houses. The main blood-feeding sources of domestic and peridomestic triatomines across the gradient were humans and chickens, respectively. The proportion of triatomines that had fed on humans did not differ between peri-urban (62.5%) and rural (65.7%) domiciles, peaking in the few domestic triatomines collected in urban houses and decreasing significantly with an increasing proportion of chicken- and dog- or cat-fed bugs. The relative odds ratio (OR) of having a T. cruzi infection was nearly threefold higher in bugs having a blood meal on humans (OR 3.15), dogs (OR 2.80) or cats (OR: 4.02) in a Firth-penalized multiple logistic model. Conclusions Trypanosoma cruzi transmission was likely occurring both in peri-urban and rural houses of Avia Terai. Widespread infestation in a third of urban blocks combined with high levels of human–triatomine contact in the few infested domiciles implies a threat to urban inhabitants. Vector control strategies and surveillance originally conceived for rural areas should be tailored to peri-urban and urban settings in order to achieve sustainable interruption of domestic transmission in the Chaco region.

scholarly journals Trypanosoma cruzi Parasite Load Modulates the Circadian Activity Pattern of Triatoma infestans

Insects ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 76
Author(s):  
Francisco Chacón ◽  
Catalina Muñoz-San Martín ◽  
Antonella Bacigalupo ◽  
Bárbara Álvarez-Duhart ◽  
Rigoberto Solís ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Trypanosoma Cruzi ◽  
Parasite Load ◽  
Triatoma Infestans ◽  
Oral Transmission ◽  
Host Seeking ◽  
Blood Sucking ◽  
Triatomine Species ◽  
Seeking Behavior ◽  
First Time

American trypanosomiasis is a disease caused by the flagellate protozoan Trypanosoma cruzi, which is transmitted mainly in endemic areas by blood-sucking triatomine vectors. Triatoma infestans is the most important vector in the southern cone of South America, exhibiting a nocturnal host-seeking behavior. It has been previously documented that the parasite produces changes in some triatomine species, but this is the first time that the behavior of a vector has been evaluated in relation to its parasite load. After comparing the movement events and distance traveled of infected and non-infected T. infestans, we evaluated the change produced by different T. cruzi parasite loads on its circadian locomotor activity. We observed differences between infected and non-infected triatomines, and a significant relation between the parasite load and the increase in locomotor activity of T. infestans, which was accentuated during the photophase. This could have direct implications on the transmission of T. cruzi, as the increased movement and distance traveled could enhance the contact of the vector with the host, while increasing the predation risk for the vector, which could both constitute a risk for vectorial and oral transmission to mammals.

Kindling, Logs, and Coals: The Dynamics of Trypanosoma cruzi, the Etiological Agent of Chagas Disease in Arequipa, Peru

2020 ◽  
pp. 215-226
Author(s):  
Michael Z. Levy
Keyword(s):  
Trypanosoma Cruzi ◽  
Salivary Glands ◽  
Chagas Disease ◽  
Etiologic Agent ◽  
Etiological Agent ◽  
Insect Vector ◽  
Blood Sucking ◽  
Vector Borne ◽  
Triatomine Insects

The forces that lead to the emergence of Trypanosoma cruzi, the etiologic agent of Chagas disease, are often distinct from those that maintain its transmission, and these are distinct again from those that allow the parasite to persist over decades. Just as kindling, logs, and coals all play discrete roles in the growth of a fire, a myriad of mammalian hosts contribute differently to epidemics of Trypanosoma. cruzi. Chagas disease affects millions of people in the Americas, and, through migration, thousands more on other continents. The agent of the disease, Trypanosoma cruzi, is a slender, highly-motile, unicellular parasite. T. cruzi does not migrate to the salivary glands of its insect vector–the blood-sucking triatomine insects–as many other vector-borne parasites do.

scholarly journals Bottlenecks in domestic animal populations can facilitate the emergence of Trypanosoma cruzi , the aetiological agent of Chagas disease

2015 ◽  
Vol 282 (1810) ◽  
pp. 20142807 ◽  
Author(s):  
Michael Z. Levy ◽  
Aaron Tustin ◽  
Ricardo Castillo-Neyra ◽  
Tarub S. Mabud ◽  
Katelyn Levy ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Guinea Pig ◽  
Chagas Disease ◽  
Domestic Animal ◽  
Infection Prevalence ◽  
Aetiological Agent ◽  
Force Of Infection ◽  
Animal Populations ◽  
Triatomine Bugs ◽  
High Infection

Faeces-mediated transmission of Trypanosoma cruzi (the aetiological agent of Chagas disease) by triatomine insects is extremely inefficient. Still, the parasite emerges frequently, and has infected millions of people and domestic animals. We synthesize here the results of field and laboratory studies of T. cruzi transmission conducted in and around Arequipa, Peru. We document the repeated occurrence of large colonies of triatomine bugs (more than 1000) with very high infection prevalence (more than 85%). By inoculating guinea pigs, an important reservoir of T. cruzi in Peru, and feeding triatomine bugs on them weekly, we demonstrate that, while most animals quickly control parasitaemia, a subset of animals remains highly infectious to vectors for many months. However, we argue that the presence of these persistently infectious hosts is insufficient to explain the observed prevalence of T. cruzi in vector colonies. We posit that seasonal rains, leading to a fluctuation in the price of guinea pig food (alfalfa), leading to annual guinea pig roasts, leading to a concentration of vectors on a small subpopulation of animals maintained for reproduction, can propel T. cruzi through vector colonies and create a considerable force of infection for a pathogen whose transmission might otherwise fizzle out.

scholarly journals Novel repellents for the blood-sucking insects Rhodnius prolixus and Triatoma infestans, vectors of Chagas disease

2019 ◽  
Author(s):  
Melanie Ramírez ◽  
Mario I. Ortiz ◽  
Pablo Guerenstein ◽  
Jorge Molina
Keyword(s):  
Chagas Disease ◽  
Dimethyl Sulfide ◽  
Control Strategies ◽  
Statistical Tests ◽  
Positive Control ◽  
Negative Control ◽  
Rhodnius Prolixus ◽  
Triatoma Infestans ◽  
Host Seeking ◽  
Blood Sucking

AbstractBackgroundStudying the behavioral response of blood-sucking, disease-vector insects to potentially repellent volatile compounds could shed light on the development of new control strategies. Volatiles released by human facial skin microbiota play different roles in the host-seeking behavior of triatomines. We assessed the repellency effect of such compounds of bacterial origin on Triatoma infestans and Rhodnius prolixus, two important vectors of Chagas disease in Latin America.MethodsUsing an exposure device, insects were presented to human odor alone (negative control) and in the presence of three individual tested compounds (2-mercaptoethanol, dimethyl sulfide and 2-phenylethanol, which was only tested in R. prolixus) and the gold-standard repellent NN-diethyl-3-methylbenzamide–DEET (positive control). We quantified the time the insects spent in the proximity of the host and performed nonparametric statistical tests to determine if any of the compounds evaluated affected the behavior of the insect.ResultsWe found volatiles that significantly reduced the time spent in the proximity of the host. These were 2-phenylethanol and 2-mercaptoethanol for R. prolixus, and dimethyl sulfide and 2-mercaptoethanol for T. infestans. Such an effect was also observed in both species when DEET was presented, although only at the higher doses tested.ConclusionsThe new repellents modulated the behavior of two Chagas disease vectors belonging to two different triatomine tribes, and this was achieved using a dose up to three orders of magnitude lower than that needed to evoke the same effect with DEET. Future efforts in understanding deeply the mechanism of action of repellent compounds such as 2-mercaptoethanol, as well as an assessment of their temporal and spatial repellent properties, could lead to the development of novel control strategies for insect vectors refractory to DEET.

scholarly journals Trypanosoma Cruzi Affects The Sensory Biology of Triatoma Dimidiata (Hemiptera: Reduviidae).

2021 ◽  
Author(s):  
Irving J. May-Concha ◽  
Maryrose J. Escalante Talavera ◽  
Jean-Pierre Dujardin ◽  
Etienne Waleckx
Keyword(s):  
Population Dynamics ◽  
Multivariate Analysis ◽  
Phenotypic Plasticity ◽  
Trypanosoma Cruzi ◽  
Protozoan Parasite ◽  
Etiologic Agent ◽  
Sensory Biology ◽  
Thin Walled ◽  
Positive Effect ◽  
New Habitats

Abstract Background: Triatoma dimidiata is a vector of the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease. Phenotypic plasticity allows an organism to adjust its phenotype in response to stimuli or environmental conditions. Understanding the effect of T. cruzi on the phenotypic plasticity of its vectors, known as triatomines, has attracted great interest because of the implications of the parasite-triatomine interactions in the eco-epidemiology and transmission of the parasite. We investigated whether the infection of the vector with T. cruzi can change the antennal phenotype of sylvatic, domestic, and laboratory-reared populations of T. dimidiata. Methods: The abundance of each type of sensillum (bristles, basiconic, thick- and thin-walled trichoid) on the antennae of T. cruzi-infected and non-infected T. dimidiata reared in the laboratory or collected in sylvatic and domestic ecotopes were measured under light microscopy and compared using Kruskal–Wallis non-parametric tests and Permutational Multivariate Analysis of Variance. Results: We found significant differences between sensilla patterns of infected and non-infected insects within sylvatic and domestic populations. Conversely, we found no significant differences between sensilla patterns of infected and non-infected insects within the laboratory-reared population. Besides, our results show that the infection with T. cruzi affects the sexual dimorphism linked to antennal phenotype in sylvatic and domestic populations. Conclusion: These differences could be linked, for infected insects, to higher efficiency in the perception of odor molecules related to the search of distant mates and hosts and for flight dispersal in search of new habitats, and the possibility of a positive effect on population dynamics and on the vectorial transmission of T. cruzi.

Sign in / Sign up

Export Citation Format

Share Document