Persistent infection of Mongolian jirds with a non-pathogenic trypanosome,Trypanosoma (Herpetosoma) grosi

Abstract

Non-pathogenic trypanosomes of the subgenus Herpetosoma are normally host specific, and laboratory models include Trypanosoma lewisi in rats and Trypanosoma musculi in mice. Two isolates of Trypanosoma grosi, originating from Apodemus agrarius and Apodemus peninsulae, grew well in Mongolian jirds, Meriones unguiculatus, after intraperitoneal inoculation of 2 x 10(5) or a minimum 500 bloodstream forms. The course of T. grosi infection in jirds resembled T. musculi infection in mice, rather than T. lewisi infection in rats. At week 2 to 3 p.i. trypanosomes disappeared from the bloodstream, and neither prednisolone treatment nor splenectomy prevented parasite elimination from the bloodstream. However, these treatments induced a marked increase in peak parasite counts. Regardless of prednisolone treatment or splenectomy, all jirds after day 21 p.i. became resistant to the reinfection. Although no trypanosomes were detected in the bloodstream of recovered jirds, dividing parasites persisted in the medullary capillaries of the kidney, like T. musculi infection in mice. We propose the T. grosi infection in jirds as an additional laboratory model for the study of non-pathogenic trypanosomes.

Blood parasites of the striped field mouse Apodemus agrarius and their morphological characteristics

“…The results of morphometric studies of trypanosomes obtained from A. agrarius from Slovakia are in accordance with results obtained by Sato et al (2003), undertaken on SESUJI isolate T. grosi from A. agrarius caught in Vladivostok, Russia. These findings coupled with our present results confirm the morphological distinctness of Trypanosoma grosi strains parasitizing several species of Apodemus mice.…”

Temporal and spatial dynamics of trypanosomes infecting the brush-tailed bettong (Bettongia penicillata): a cautionary note of disease-induced population decline

“…No divisional stages of this parasite have been observed in the peripheral blood of the woylie, despite an extensive morphological investigation [6]. Dividing trypomastigotes, which are essential for maintaining the infection within the woylie, may be confined to the internal organs of the host, similar to Trypanosoma grosi within the Mongolian jird ( Meriones unguiculatus ), where dividing forms have been identified within the capillaries of the kidneys long after trypomastigote detection ceased from the peripheral blood [27]. …”

Trypanosoma (Herpetosoma) kuseli sp. n. (Protozoa: Kinetoplastida) in Siberian flying squirrels (Pteromys volans)

“…We could detect only low levels of parasitaemia (up to 2.0×10 5 /ml of blood) by T. otospermophili in jirds, compared with those resulting from longlasting T. grosi and short-lasting T. lewisi infection in prednisolone-treated jirds (Sato et al 2003(Sato et al -2005. Hydrothorax killed some infected jirds with T. otospermophili, and the pleural effusion contained 2.4×10 8 developed as well as dividing trypanosomes/ml (Fig.…”

“…Trypanosoma otospermophili from a Columbian ground squirrel was expanded by in vitro culture as described previously (Sato et al 2003). Cultured trypanosomes were resuspended in supplemented RPMI 1640 medium in the absence of fetal calf serum.…”

“…In addition, we carried out an experimental infection of laboratory jirds (Meriones unguiculatus) with the latter species according to our previous studies (Sato et al 2003(Sato et al -2005, which demonstrated high usability of jirds as experimental hosts for Herpetosoma trypanosomes of field mice, i.e. Trypanosoma grosi.…”