Penetração do Trypanosoma cruzi através do ponto da picada de triatomíneos

Soares, V.A.; Marsden, P.D.

doi:10.1590/s0037-86821986000300007

Cited by 7 publications

(6 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, metacyclic trypomastigotes, the natural infective phase for mammals, are responsible for infection. Metacyclic trypomastigotes access the body across small wounds on the skin or via mucous membranes (Brumpt, 1912 ;Romañ a, 1943 ;Soares & Marsden, 1986). Sequential description of inflammatory reaction at the inoculation site has shown polymorphonuclear cells (PMN) as early as 1 h after inoculation and peaks at 24 h. These PMN are gradually replaced by mononuclear cells (MN) that become predominant by day 15 after infection.…”

Section: Discussionmentioning

confidence: 99%

Description of inflammation and cytokine profile at the inoculation site and in heart tissue of mice re-infected with Trypanosoma cruzi vector derived-metacyclic trypomastigotes

et al. 2005

View full text Add to dashboard Cite

We studied the role of Trypanosoma cruzi reinfection in regard to inflammatory and cytokine response at the inoculation site, lymph node and heart. We reinfected Balb/c mice intradermically into the hind foot-pad with natural infective metacyclic trypomastigotes. They were followed from 24 h to 30 days after the last reinfection. At the inoculation site 24 h after the last re-infection, the infiltrating inflammatory cells increased dramatically with respect to baseline inflammation, reaching maximum infiltrates for the third day. In contrast, parasite DNA was undetectable 24 h after inoculation, despite poor cytokine induction, only IFN-gamma, IL-12 and TGF-beta were noticeable on days 7 and 15, whereas in the lymph nodes draining the inoculation site positive expression of IL-2, IL-4, IL-12 and TGF-beta were found to be induced as soon as 24 h after re-entry of parasite. In the heart, the inflammatory response increased immediately 24 h after re-entry of parasites, reaching its maximum on the 7th day and returning to baseline on day 30. In conclusion, although the inflammatory response is triggered in both compartments by re-entry of parasites, the inflammatory process returns almost to baseline after 30 days, leaving a persistent low-grade inflammation.

show abstract

Section: Discussionmentioning

confidence: 99%

Description of inflammation and cytokine profile at the inoculation site and in heart tissue of mice re-infected with Trypanosoma cruzi vector derived-metacyclic trypomastigotes

et al. 2005

View full text Add to dashboard Cite

show abstract

“…The possibility that the feeding wound of the vector’s mouthparts offer an entry was investigated by placing 2,500 T . cruzi in 50 µl excreta of triatomines for 45 min onto the intact skin of a mouse and onto the feeding wound of a third instar nymph of D. maxima (Soares and Marsden 1986 ). This resulted in no infection for the intact skin and an infection rate of 24% for the feeding wound.…”

Section: Discussionmentioning

confidence: 99%

“…Infections via the feeding wound of the triatomine vector have been considered several times (e.g. Soares and Marsden 1986 ; Schuster and Schaub 2000 ; Eickhoff et al 2013 ), but the size of wounds caused by the mouthparts of triatomines and the number of parasites invading via the feeding wound have not been determined. In the present investigation, the sizes of the mouthparts of different stages of triatomines were measured.…”

Section: Introductionmentioning

confidence: 99%

“Natural infections” with Trypanosoma cruzi via the skin of mice: size of mouthparts of vectors and numbers of invading parasites

Waldeck

Schaub

2022

Parasitol Res

View full text Add to dashboard Cite

Investigating parameters influencing natural infections with Trypanosoma cruzi via the skin, the diameters of mouthparts of different stages of triatomines vectors were measured to determine the size of the channel accessible for T. cruzi during cutaneous infection. The mean diameters of the skin-penetrating mandibles of first to fifth instar nymphs of the vector Triatoma infestans increased from 18 to 65 µm. The mean diameter in fourth instar nymphs of Dipetalogaster maxima was 86 µm. Different numbers of isolated vector-derived metacyclic trypomastigotes (10–10,000) were injected intradermally into mice. Prepatent periods, parasitemia and mortality rates were compared with those of mice obtaining 10,000 metacyclic trypomastigotes that are usually present in the first drop of faeces onto the feeding wounds of fifth and fourth instar nymphs of T. infestans and D. maxima, respectively. After injection of 50–10,000 T. cruzi, in all 42 mice the infection developed. An injection of 10 parasites induced an infection in 8 out of 15 mice. With increasing doses of parasites, prepatent periods tended to decrease. The level of parasitemia was higher after injection of the lowest dose. Except for one mouse all infected mice died. After placement of 10,000 metacyclic trypomastigotes onto the feeding wound of fifth or fourth instar nymphs of T. infestans and D. maxima, respectively, the infection rates of the groups, prepatent periods and the levels of parasitemia of T. cruzi in mice indicated that about 10–1,000 metacyclic trypomastigotes entered the skin via this route. For the first time, the present data emphasise the risk of an infection by infectious excreta of triatomines deposited near the feeding wound and the low number of invading parasites.

show abstract

“…Significant differences between the percentages of the forms of T. cruzi in the intestines of the different species were also found (Szumlewicz & Müller 1979, 1982, 1987. On the other hand, it was demonstrated (Soares & Marsden 1986) that T. cruzi was only capable of penetrating through the bite site in 24% of the animals (mice). It could finally be concluded that the chances of natural infection of humans by T. cruzi would not be very high if it were not for the long and intense contact with infected triatomines that is accumulated over the course of life, with hundreds of opportunities, from which one such contact might lead to infection.…”

Section: Determinants Of Chagas Infectionmentioning

confidence: 94%