that the relevance and availability of leptospirosis models is variable
in many countries affected by leptospirosis, such as Australia.
Importantly, all methods presented here on the hamster model
can directly be transposed to the mouse model, using specific
mouse qPCR primers.
2 Materials
2.1 Animals
1. Golden Syrian hamsters (Mesocricetus auratus): 6- to 8-weekold, male and female hamsters are used for infection experiments (see Notes 1 and 2). Body mass of laboratory hamsters
between 6 and 8 weeks might be approximately 100 Æ 10 g
[17]. Hamsters are housed in cages with 1–5 animals per cage,
in the animal house facility with controlled temperature and
light conditions (ambient temperature, 20–24
C; relative
humidity, 55–65%; semi-artificial light-dark cycle of 12 L:12
D hours), except during experimental procedures. Food and
water are provided ad libitum, and sunflower or millet seeds are
distributed as part of their environmental enrichment, at the
time of cage cleaning and/or daily check during an experiment.
2.2 Leptospira
Culture
1. Leptospira interrogans serovar Icterohaemorrhagiae strain Verdun (LiVV; see Note 3): Leptospires are cultivated in glass
tubes with screw cap filled with liquid Ellinghausen, McCullough, Johnson, and Harris (EMJH) medium at 30
C under
aerobic conditions (with loosely closed screw cap for tube
aeration) and possibly with shaking to boost the bacterial
growth if required. Cultures used for experimental infections
should be in the course of their exponential phase of growth.
Bacterial virulence is regularly maintained by intraperitoneally
injecting hamsters and isolating leptospires from infected animals’ blood.
2. EMJH basal salt solution: Dissolve 2.3 g of Difco™ Leptospira
Medium Base EMJH (Becton Dickinson) in 900 mL of distilled or deionized water and autoclave.
3. Albumin supplement (for 1 L): Mix together 100 g of bovine
serum albumin, 10 mL of ZnSO 4 (stock 0.4 g/100 mL of ZnSO 4 ·7H 2 O), 10 mL of MgCl 2 (stock 1.5 g/100 mL of
MgCl 2 ·6H 2 O), 10 mL of CaCl 2 (stock 1.5 g/100 mL of
CaCl 2 ·2H 2 O), 10 mL of sodium pyruvate (stock 10 g/
100 mL of sodium pyruvate), 20 mL of bi-distilled glycerin
(stock 20 g/100 mL of bi-distilled glycerin), 125 mL of Tween
80 (11.58 g of Tween 80 in sterile water, final volume of
125 mL), 1 mL of CuSO 4 (stock 0.3 g/100 mL of
CuSO 4 ·5H 2 O), 100 mL of FeSO 4 (0.5 g of FeSO 4 ·7H 2 O in
100 mL of sterile water), and 4 mL of 500 μg/mL vitamin
Hamsters as a Model to Study Leptospirosis
245
in many countries affected by leptospirosis, such as Australia.
Importantly, all methods presented here on the hamster model
can directly be transposed to the mouse model, using specific
mouse qPCR primers.
2 Materials
2.1 Animals
1. Golden Syrian hamsters (Mesocricetus auratus): 6- to 8-weekold, male and female hamsters are used for infection experiments (see Notes 1 and 2). Body mass of laboratory hamsters
between 6 and 8 weeks might be approximately 100 Æ 10 g
[17]. Hamsters are housed in cages with 1–5 animals per cage,
in the animal house facility with controlled temperature and
light conditions (ambient temperature, 20–24
C; relative
humidity, 55–65%; semi-artificial light-dark cycle of 12 L:12
D hours), except during experimental procedures. Food and
water are provided ad libitum, and sunflower or millet seeds are
distributed as part of their environmental enrichment, at the
time of cage cleaning and/or daily check during an experiment.
2.2 Leptospira
Culture
1. Leptospira interrogans serovar Icterohaemorrhagiae strain Verdun (LiVV; see Note 3): Leptospires are cultivated in glass
tubes with screw cap filled with liquid Ellinghausen, McCullough, Johnson, and Harris (EMJH) medium at 30
C under
aerobic conditions (with loosely closed screw cap for tube
aeration) and possibly with shaking to boost the bacterial
growth if required. Cultures used for experimental infections
should be in the course of their exponential phase of growth.
Bacterial virulence is regularly maintained by intraperitoneally
injecting hamsters and isolating leptospires from infected animals’ blood.
2. EMJH basal salt solution: Dissolve 2.3 g of Difco™ Leptospira
Medium Base EMJH (Becton Dickinson) in 900 mL of distilled or deionized water and autoclave.
3. Albumin supplement (for 1 L): Mix together 100 g of bovine
serum albumin, 10 mL of ZnSO 4 (stock 0.4 g/100 mL of ZnSO 4 ·7H 2 O), 10 mL of MgCl 2 (stock 1.5 g/100 mL of
MgCl 2 ·6H 2 O), 10 mL of CaCl 2 (stock 1.5 g/100 mL of
CaCl 2 ·2H 2 O), 10 mL of sodium pyruvate (stock 10 g/
100 mL of sodium pyruvate), 20 mL of bi-distilled glycerin
(stock 20 g/100 mL of bi-distilled glycerin), 125 mL of Tween
80 (11.58 g of Tween 80 in sterile water, final volume of
125 mL), 1 mL of CuSO 4 (stock 0.3 g/100 mL of
CuSO 4 ·5H 2 O), 100 mL of FeSO 4 (0.5 g of FeSO 4 ·7H 2 O in
100 mL of sterile water), and 4 mL of 500 μg/mL vitamin
Hamsters as a Model to Study Leptospirosis
245