Comparing vector competence of Mepraia gajardoi and Triatoma infestans by genotyping Trypanosoma cruzi discrete typing units present in naturally infected Octodon degus

Acta Tropica ◽  
2019 ◽  
Vol 190 ◽  
pp. 119-122
Author(s):  
Alejandra Sandoval-Rodríguez ◽  
Gemma Rojo ◽  
Angélica López ◽  
Sylvia Ortiz ◽  
Miguel Saavedra ◽  
...  
2019 ◽  
Vol 110 (1) ◽  
pp. 169-176 ◽  
Author(s):  
N. Pereyra ◽  
P.A. Lobbia ◽  
G. Mougabure-Cueto

AbstractTransmission of Trypanosma cruzi (Kinetoplastida: Trypanosomatidae) occurs when feces/urine of infected triatomines come into contact with mucous membranes or damaged skin, and this occurs mainly when insects defecate while feeding on the host. Thus, the vector competence of the triatomines is associated with their feeding and excretion/defecation behavior. This work studied for the first time the effect of T. cruzi infection on feeding and excretion/defecation patterns of Triatoma infestans (Hemiptera: Reduviidae). Uninfected and infected fifth-instar nymphs were fed ad libitum and their feeding behavior and defecations were registered during and after feeding. The feeding pattern did not show differences between the experimental groups. However, the infected nymphs began to defecate earlier, defecated in greater quantity and there was a greater proportion of defecating individuals compared to uninfected nymphs. These results show that T. cruzi affected the excretion/defecation pattern of T. infestans in a way that would increase the probability of contact between infective feces and the mammalian host.


Author(s):  
Ingrid dos Santos da Silva ◽  
Mônica de França Guedelha ◽  
Cíntia Alves da Silva ◽  
Lara Cristina Santos ◽  
Angela Cristina Verissimo Junqueira ◽  
...  

Chagas is a neglected disease, one of Brazil’s main medical and social problems and a serious public health problem in the Americas, with more recent occurrences in non-endemic countries outside of the Americas. Research into the microbiota of triatomines is relevant because of its potential role in vector competence and as a proposed biological control strategy. Stressing a possible insect-fungal interaction in the development of Trypanosoma cruzi, and considering the lack of studies on the subject, we analyzed the fungal microbiota of the digestive tract of two species considered important vectors of Trypanosoma cruzi: Triatoma infestans and Panstrongylus megistus. Specimens were dissected, digestive tracts macerated and contents serially diluted. Each aliquot was seeded in three culture media. The plates were incubated in type B.O.D. climate chambers for 21 days, after which isolated colonies were morphological characterized and identified. There have been few published studies on the fungal microbiota of the triatomine digestive tract. Comparing the results found here with existing data reveals that the genera Aspergillus and Penicillium are commonly found in the digestive tract of the studied triatomines. Among the several genera identified, the species found in the highest percentages were Aspergillus flavus, Paecilomyces variotii, Penicillium waksmanii, Penicillium raistrickii and Penicillium fellutanum. Quantitative differences in the number of isolated fungal strains were observed according to sex and nymphal stage of the vector. The present findings corroborate those found in the literature, showing that there is a natural fungal microbiota in triatomines. Data revealing quantitative differences in isolated fungal strains found in male, female and nymphs reinforce the idea that their presence is related to physiology and fasting resistance. The secondary metabolite-producing fungi isolated in this work have in their biology great potential to be tested with regard to the establishment of T. cruzi in the digestive tract of its vector.


1988 ◽  
Vol 101 (3) ◽  
pp. 655-660 ◽  
Author(s):  
Th. Weinke ◽  
K. Ueberrieiter ◽  
M. Alexander

SUMMARYThe prevalence of cardiac morbidity due to Change' disease was assessed in a rural community in Central Bolivia. Sixty-nine of 104 persons (66%) were seropositive to Trypanosoma cruzi by two serological methods. Two of 35 (6%) seronegative individuals presented with modest ECG alterations (left anterior hemiblock), but 21 of 69 (30%) seropositives showed modest and severe abnormalities (6 complete right bundle branch block. 2 polyfocal or frequent extrasystoles, 9 ischaemic ST alterations). A high percentage (56%) of domiciliary Triatoma infestans was infected with T. cruzi. There was a significant association between seropositivity and substandard housing. Priority preventive measures should thus include house improvement (to reduce bug infestation) and health education.


1982 ◽  
Vol 77 (4) ◽  
pp. 431-436 ◽  
Author(s):  
Nelson J. Alvarenga ◽  
Elizabeth Bronfen

O exame da hemolinfa de triatomíneos (Triatoma infestans e Dipetalogastermaxima) infectados pelo Trypanosoma cruzi há 10, 15, 20 e 30 dias não revelaram a presença do flagelado. Material colhido e lavado da hemocele de D. maxima infectados, também foi negativo. A inoculação de formas sanguíneas do parasita e daquelas obtidas do conteúdo intestinal de triatomíneos na hemocele revelou que os parasitas não foram capazes de manter na hemolinfa uma infecção por mais de 40 dias e que não puderam penetrar no intestino dos triatomíneos. A inoculação de hemolinfa de insetos naturalmente infectados em camundongos recém-nascidos não induziu infecção.


1996 ◽  
Vol 29 (6) ◽  
pp. 549-555 ◽  
Author(s):  
M. Esther Bar ◽  
E.B. Oscherov ◽  
M.P. Damborsky ◽  
B.M. Alvarez ◽  
G. Mizdraji ◽  
...  

Se llevó a cabo un estúdio epidemiológicopara obtener unpanorama general de la transmisión doméstica del Trypanosoma cruzi en áreas rurales del Departamento San Miguel, Conientes, Argentina. Se investigaron 100 viviendas precarias, 50,0% de las mismas resultó infestado por Triatoma infestans y 1,0% por T. sórdida, citãndose por primera vez para la provinda de Comentes la colonización domiciliaria de esta especie. El 23,1% de T. infestans estaba infectado por T. cruzi. La seroprevalencia de 388 pacientes analizados por hemaglutinacíôn indirecta e inmunofluorescencia indirecta fue 23,4%, destacándose el alto índice (12,9%) constatado en menores de 10 anos. Losporcentajes de seropositividad aumentaron con la edad, alcanzándose 50,0% de infectados entre los 31-40 anos. La infestación doméstica por T. infestans, la prevalencia humana de seropositivos al T. cruzi y las condiciones deprecariedad en que se desenvuelve la vida de los pobladores revelan la vigência de la endemia chagãsica en el área estudiada.


2004 ◽  
Vol 59 (3-4) ◽  
Author(s):  
INÉS ZULANTAY ◽  
FRANCISCA BOZÁN ◽  
CARLOS SALAS ◽  
NICOLÁS ZILLERUELO ◽  
ANTONIO OSUNA ◽  
...  

Author(s):  
Juciliane Haidamak ◽  
Márcia Kiyoe Shimada ◽  
Débora do Rocio Klisiowicz ◽  
Larissa Reifur

A Bahia foi o último estado brasileiro a ser declarado livre da transmissão da doença deChagas pelo Triatoma infestans em 2006. O programa designado para controle vetorial da transmissão da doença de Chagas está atualmente ativo, e os potenciais triatomíneos coletados por funcionários do Departamento da Saúde do Estado da Bahia são praticamente todos diagnosticados como negativos para Trypanosoma cruzi quando analisados pelo método parasitológico convencional direto. O objetivo deste estudo foi investigar se os triatomíneos da Bahia, de fato, não estão infectados por T. cruzi, utilizando-se, para isso, uma metodologia de diagnóstico mais sensível, como a reação em cadeia da polimerase do DNA do cinetoplasto (kDNA-PCR). Com a ajuda dos funcionários da área da saúde, foram analisados 51 triatomíneos provenientes de áreas do peridomicílio da região centro-norte do estado da Bahia.Dos insetos analisados, a maioria (60,8%) era Triatoma brasiliensis, 29,4% eram Triatoma pseudomaculata e 9,8% eram ninfas que não foram identificadas. Apenas um inseto, analisado pelo método parasitológico convencional direto, mostrou-se potencialmente positivo para T. cruzi e 31,4% foram positivos para T. cruzi pela kDNA-PCR. Quase a metade dos insetos infectados (41,9%) era constituída por T. brasiliensis, uma espécie com alto potencial para a transmissão de T. cruzi. Estes resultados demonstram que o número de triatomíneos infectados com elevado potencial de transmissão de T. cruzi pode ser maior do que o esperado em quatro localidades do estado da Bahia.


2021 ◽  
Vol 15 (5) ◽  
pp. e0009389
Author(s):  
Marta Victoria Cardinal ◽  
Gustavo Fabián Enriquez ◽  
Natalia Paula Macchiaverna ◽  
Hernán Darío Argibay ◽  
María del Pilar Fernández ◽  
...  

Background Interruption of domestic vector-borne transmission of Trypanosoma cruzi is still an unmet goal in several American countries. In 2007 we launched a long-term intervention program aimed to suppress house infestation with the main domestic vector in southern South America (Triatoma infestans) and domestic transmission in Pampa del Indio, a resource-constrained, hyperendemic municipality with 1446 rural houses inhabited by Creole and indigenous people, in the Argentine Chaco ecoregion. Here, we assessed whether the 10-year insecticide-based program combined with community mobilization blocked vector-borne domestic transmission of T. cruzi to humans and dogs. Methods We carried out two municipality-wide, cross-sectional serosurveys of humans and dogs (considered sentinel animals) during 2016–2017 to compare with baseline data. We used a risk-stratified random sampling design to select 273 study houses; 410 people from 180 households and 492 dogs from 151 houses were examined for antibodies to T. cruzi using at least two serological methods. Results The seroprevalence of T. cruzi in children aged <16 years was 2.5% in 2017 (i.e., 4- to 11-fold lower than before interventions). The mean annual force of child infection (λ) sharply decreased from 2.18 to 0.34 per 100 person-years in 2017. One of 102 children born after interventions was seropositive for T. cruzi; he had lifetime residence in an apparently uninfested house, no outside travel history, and his mother was T. cruzi-seropositive. No incident case was detected among 114 seronegative people of all ages re-examined serologically. Dog seroprevalence was 3.05%. Among native dogs, λ in 2016 (1.21 per 100 dog-years) was 5 times lower than at program onset. Six native adult dogs born after interventions and with stable lifetime residence were T. cruzi-seropositive: three had exposure to T. infestans at their houses and one was an incident case. Conclusions These results support the interruption of vector-borne transmission of T. cruzi to humans in rural Pampa del Indio. Congenital transmission was the most likely source of the only seropositive child born after interventions. Residual transmission to dogs was likely related to transient infestations and other transmission routes. Sustained vector control supplemented with human chemotherapy can lead to a substantial reduction of Chagas disease transmission in the Argentine Chaco.


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 ◽  
...  

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.


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