Efficient infection of hamster with Leishmania donovani by retro-orbital inoculation

Figures & data

Figure 1. Live weight gain of experimental hamsters along the experimental infection with 10⁸ stationary phase promastigotes of Leishmania donovani (MHOM/SD/43/124). (○): uninfected control animals; (■): hamsters inoculated by the retro-orbital route; (▼): animals infected by intraperitoneal inoculation; (△): animal group infected by via intracardiac injection. Values are means ± standard error of the mean (SEM).

Figure 2. Peripheral serum antibody response of hamsters inoculated with L.donovani by retro-orbital (RO), intracardiac (IC) and intraperitoneal (IP) routes along the experimental period estimated by ELISA. (a) Serum IgG response. (b) Serum IgG₂ response. (○) uninfected, (■) RO, (▼) IP, and (△) IC. (c) Comparison of serum IgG, IgG₁ and IgG₂ levels of experimental groups of hamsters inoculated by different routes at the end point of the experiment. Values are mean ± SEM. **P < 0.01 and ****P < 0.0001: significant differences. Cut off was established at 0.167 for IgG, 0.027 for IgG₁ and 0.049 for IgG_2.

Table 1. Spleen and liver weight of experimental animals (mean±SEM) at the end point of the experiment.

Group	Spleen	Liver
C	0.170 ± 0.008*^RO, IC	6.699 ± 0.663
RO	0.224 ± 0.052*^C, IP	6.700 ± 1.166
IP	0.170 ± 0.031	6.527 ± 0.859
IC	0.214 ± 0.059*^C	6.898 ± 1.013

*Superscripts indicate significant differences (P < 0.05).

C: control animals; RO: retro-orbital inoculation; IP: intraperitoneal inoculation; IC: intracardiac inoculation.

Figure 3. Spleen (a) and liver (b) relative weight to the total live weight of experimental hamsters inoculated with L.donovani by different routes. Abbreviations as in Figure 2. Values are means ± SEM. *P < 0.05: significant differences.

Figure 4. Levels (mean±SEM) of hepatic and liver functionality markers of hamsters inoculated with L.donovani by different routes at the end point of the experiment. (a) alanine aminotransferase (ALT); (b) aspartate aminotransferase (AST); (c) AST/ALT; (d) alkaline phosphatase (ALP); (e) creatinine; (f): urea. *P < 0.05; **P < 0.01: significant differences.

Table 2. Leishmania parasite burden (PB, parasites/gram) (Mean ± SEM) in spleen and liver estimated by Limiting Dilution Assay (LDA) at the end of the experiment.

Group	Spleen	Liver
C	0.00 ± 0.00	0.00 ± 0.00
RO	1.58 x10^8 ± 1.88 x10^8 * IP (6/6)	1.23 x10^7 ± 1.61 x10^7 (6/6)
IP	8.70 x10^6 ± 13.84 x10^6 * RO, IC (4/5)	2.07 x10^6 ± 3.52 x10^6 *IC (4/5)
IC	1.47 x10^8 ± 1.90 x10^8* IP (6/6)	1.40 x10^7 ± 1.48 x10^7 *IP (6/6)

*Significant differences (P < 0.05) with different superscripts.

C: control animals; RO: retro-orbital; IP: intraperitoneal; IC: intracardiac inoculations. In brackets: success rate of the infection (number of animals infected/number of animals inoculated).

Figure 5. Normalized L.donovani parasite burden (log) of spleen (a) and liver (b) of hamsters inoculated by different routes. Both individual and mean±SEM values are given. (■) RO, (▼) IP, and (△) IC. *P < 0.05: significant differences.