Mastomys natalensis

Sadlova, Jovana, Vojtkova, Barbora, Hrncirova, Katerina, Lestinova, Tereza, Spitzova, Tatiana, Becvar, Tomas, Votypka, Jan, Bates, Paul & Volf, Petr, 2019, Host competence of African rodents Arvicanthis neumanni, A. niloticus and Mastomys natalensis for Leishmania major, International Journal for Parasitology: Parasites and Wildlife 8, pp. 118-126 : 122-123

3.3. Experimental infections and xenodiagnosis with M. natalensis

In total, 23 M. natalensis were inoculated with two L. major strains.

Thirteen M. natalensis were all inoculated with sand fly–derived promastigotes of the Israeli strain Friedlin. Q-PCR revealed presence of L. major in 46% of the animals ( Table 1). However, none of the 13 M. natalensis tested developed lesions or other external signs of the disease. Leishmania were localized mostly in the inoculated ear pinnae (4 animals), less often in the contralateral ear pinnae (3 animals) and exceptionally also in a forepaw (1 animal) and liver (1 animal). However, since parasites were present in very low numbers (less than 100) animals were not infectious to feeding sand flies ( Tables 1 and 2).

Ten M. natalensis were experimentally infected with the LV109 strain ( Table 1), 5 with sand fly-derived Leishmania (experimental group A) and 5 with culture-derived promastigotes (experimental group C). Skin swellings developed at the site of inoculation (left ear pinnae) in animals of both experimental groups approximately 10 weeks p. i. ( Table 4, Fig. 1E ). Prior to the swelling the affected site usually reddened, which was observed more often in specimens of the group C. The size of the swelling increased gradually to 6–8 mm, then decreased and niloticus . Animals C1-C5 were infected with culture-derived promastigotes (Group C), animals A1-A5

were infected with sand fly-derived Leishmania (Group A). Black colour – hyper-pigmentation, grey colour – depigmentation in the centre surrounded with hyper-pigmented borders. The numbers are the length of the affected area in mm. *, animal died by week 10 p. i.

finally disappeared. Hyper-pigmentation often accompanied healing of the swellings ( Table 4) and it mostly persisted until the end of the experiments.

Parasites were detected by Q-PCR in all tested animals and they disseminated to draining lymph nodes, forepaws, hindpaws and tail in several animals and also to the spleen in one specimen ( Table 1). Infectiousness to sand flies was tested at weeks 15 and 25 p. i.: 0.7% of females from group A became infected after feeding on week 15 p. i., while 3.3% and 4.1% of females from the group A and C, respectively, were infected feeding on week 25 p. i. ( Table 2).

Figures

Fig. 1. Xenodiagnosis and external manifestation of L. major in rodents. Direct xenodiagnosis with P. duboscqi in plastic tubes covered with fine mesh held on the ear of the anaesthetized A. niloticus (A) and external manifestation of L. major LV109 in ear pinnae (site of inoculation) of A. neumanni by week 10 p.i., (B); A. niloticus by week 30 p.i. (C, D) and M. natalensis by week 19 p.i. (E).