1.The blood-sucking bug, Triatoma protracta Uhler, and the wood rat, Neotoma fuscipes macrotis Thomas are natural carriers of Trypanosoma cruzi Chagas in southern California.
2.The following animals have been experimentally infected with this trypanosome: albino rats, albino mice, rhesus monkeys, a puppy, an opossum (Didelphis virginiana virginiana Kerr), 2 species of dusky-footed wood rats (Neotoma fuscipes annectens Elliot and N. f. macrotis Thomas), and 5 species of white-footed mice (Peromyscus eremicus fraterculus [Miller], P. californicus insignis Rhoads, P. californicus californicus [Gambel], P. maniculatus gambeli [Baird], P. truei gilberti [Allen]).
3.The San Diego desert and southern parasitic mice and the Virginia opossum have all been found in wood rat nests in the infected locality, so it is possible that they, too, are carriers.
4.Leishmania bodies were seen in bone marrow, cardiac and voluntary muscle of infected animals.
5.Lesions composed of infiltration lymphocytes, monocytes, and plasma cells have been found in cardiac and voluntary muscles, cerebrum, and meninges.
6.Animals infected by this strain take light infections, showing few parasites or lesions and usually no symptoms.
7.Neither splenectomy, injection of testicle extract, nor increased temperature have any intensifying effect upon the infection.
8.Varying the host species gave progressively shorter incubation periods, indicating a stimulating effect upon the parasite.
9.One out of five attempts to reinfect animals succeeded, indicating a partial immunity.
10.This trypanosome has been cultured on semi-solid blood agar, the culture forms being comparable to the insect phase.