Veneza zonata (Hemiptera : Coreidae)/trypanosomatid relationship: Action of hemolymph in vitro and experimental infection

The defense response of Veneza zonata (Hemiptera: Coreidae) against three d ifferent trypanosomatid infections was assessed: (1) strain 714TD, a Leptom onas which has V. zonata as vector of a plant trypanosomatid, (2) strain 56 3TD, a Leptomonas isolated from the digestive tract of Euchistus heros (Hem iptera: Pentatomidae), and (3) Leishmania (L.) amazonensis, a human parasit e that cannot infect V. zonata, Experiments with V. zonata hemolymph showed agglutination only of L. (L,) amazonensis culture forms and hemocytic reco gnition was more intense with this strain. L. (L,) amazonensis also activat ed the prophenoloxidase system, whereas strains 714TD and 563TD did not act ivate this system but rather seemed to inhibit phenoloxidase activity. No f lagellates were seen in the digestive tract, hemolymph, or salivary glands in insects infected with L. (L.) amazonensis. The digestive tract, the hemo lymph, and the salivary glands of insects fed on tomatoes inoculated with 7 14TD are sequentially invaded by the flagellate, which is inoculated in pla nts together with saliva. Insects fed on tomatoes inoculated with 563TD exh ibited culture forms in the digestive tract (6 days after) and hemocoel (th ree additional days); however, they died 12 to 14 days after exposure. The salivary glands in insects inoculated in the hemocoel with 714TD strain are rapidly invaded, whereas those with 563TD culture forms died approximately 24 h after infection. Bacterial proliferation in the hemocoel and hemocyte surface blebbing were seen in insects infected only with 563TD strain as t he probable pathogenic mechanism of insect death, (C) 2001 Academic Press.