The development of Blastocrithidia triatomae (Trypanosomatidae) in the reduviid bug Triatoma infestans (Insecta): influence of starvation

Abstract

Fifth instars of Triatoma infestans with established Blastocrithidia triatomae infections were dissected after different periods of starvation. After a short starvation period of 30 days, 60% of the total population (2,700,000 flagellates) occurred in the small intestine. Within the following 3 months, the numbers of living flagellates there (epimastigotes, cysts) were reduced by about 70% and the percentage of dead mastigotes increased to 30% of the respective total population. Epimastigotes always dominated (about 90%), followed by cysts and only up to 3% spheromastigotes. These relations were only slightly changed by starvation. In the rectum, at 30-120 days after feeding, the total population of living epimastigotes was reduced by 90% and the percentage of those attached to the rectal wall decreased from 10% to <3%. During this period, the proportion of dead from all epimastigotes increased from 34% to >99%. In the rectum, the percentage of cysts from the total population of living parasites increased from 41% to 88% at 30-60 days after feeding and remained at this percentage and total numbers, showing that especially the early phase of starvation strongly induced the encystment of B. triatomae.

A contractile vacuole complex is involved in osmoregulation in Trypanosoma cruzi

“…As T. cruzi progresses through its life cycle, it encounters diverse environmental stressors to which it must successfully adapt. Of particular interest is the parasite's ability to cope with extreme fluctuations in osmolarity that occur within the gut of the vector (Kollien et al, 2001;Kollien and Schaub, 2002) and also as the parasite moves from the insect gut through the acidic phagolysosome to the cytosol of the host cell. The infective form of the parasite passes out of the vector in the highly concentrated excreta (600-700 mOsm) (Kollien et al, 2001) and rapidly encounters the interstitial fluid of the mammalian host with a much lower osmolarity (300 mOsm).…”

The development of Blastocrithidia triatomae (Trypanosomatidae) in the reduviid bug Triatoma infestans (Insecta): influence of feeding

“…The small intestine of unfed fifth instars of Triatoma infestans was found to contain 50·10 3 or 60·10 3 T. cruzi in an unselected strain of the vector and 400·10 3 in a selected strain (summarized by Kollien and Schaub 2002). The small intestine of unfed fifth instars of Triatoma infestans was found to contain 50·10 3 or 60·10 3 T. cruzi in an unselected strain of the vector and 400·10 3 in a selected strain (summarized by Kollien and Schaub 2002).…”

“…This development is influenced by several parameters, especially by the parasite-host system. Additional factors are the region of the intestinal tract examined (summarized by Kollien and Schaub 2002) and the feeding state. The influence of the instar of bugs or the duration of the infection cannot be estimated separately if the population density increases in different instars during the course of the infection (Schaub 1989).…”

“…The influence of the instar of bugs or the duration of the infection cannot be estimated separately if the population density increases in different instars during the course of the infection (Schaub 1989). C Free cysts, F mastigote flagellates (Kollien and Schaub 2002), in the following we compare the B. triatomae populations in unfed bugs with those which had ingested a limited amount of blood 20 days earlier. Since the effects of star-x,y,z Statistically significant differences, using Student's t-test (P<0.05) for comparison of the respectivemeans.…”

“…Our previous investigation considered the effects of starvation on B. triatomae and showed that both the numbers and stages of both parasites responded differently (Kollien and Schaub 2002). after unequal divisions, we compared the response of B. triatomae and T. cruzi to changes in the milieu in the intestine.…”