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Updated: Feb 16, 2026
In vivo Imaging of Transgenic Leishmania Parasites in a Live Host
Published on: July 27, 2010
Use of In Vivo Imaging System Technology in Leishmania major BALB/c Mouse Ear Infection Studies
Alicia Cawlfield1, Brian Vesely1, Franklyn Ngundam1
1Walter Reed Army Institute of Research, Silver Spring, MD.
Abstract:
Novel treatments for cutaneous leishmaniasis (CL) are needed, due to current lack of effective universal treatments, increasing resistance among the parasite, and toxic effects or impracticality of the current therapeutics. Models of direct infection with high number of Leishmania parasites in the current research of CL involving the BALB/c mouse or Golden Syrian Hamster are considered not suitable for the assessment of antileishmanial drug efficacy because of the lack of disease similarities with humans. The saliva of the sand fly vector is known to affect the host response to infection by the Leishmania parasite. Here, we build upon a previous BALB/c model infected with luciferase-expressing Leishmania major parasites. In the present study, we infect the ear dermis instead of the foot pad or base of the tail, and compare multiple methods of infection, using parasites alone or mixed with either bites from uninfected sand flies (Phlebotomus duboscqi Diptera Psychodidae:Neveu-Lemaire) or salivary gland sonicate from sand flies. Our data show a dose-response of bioluminescent signal (which represents the parasite load at the infection site), dermal lesion development, and Leishmania Donovan Units in liver and spleen. This in vivo L. major ear infection model, once optimized, can be used for assessing the efficacy of drug compounds that have been determined as very effective in the other, high inoculum CL models.
Insights
Developing a new mouse model for cutaneous leishmaniasis (CL) infection in the ear dermis improves assessment of antileishmanial drug efficacy. This optimized model better mimics human disease for evaluating novel CL treatments.
Area of Science:
- Parasitology and Tropical Diseases
- Infectious Disease Modeling
- Drug Discovery and Development
Background:
- Current cutaneous leishmaniasis (CL) treatments face challenges including parasite resistance, toxicity, and impracticality.
- Existing mouse models (BALB/c, Golden Syrian Hamster) with high Leishmania parasite loads lack disease similarity to human CL.
- Sand fly saliva influences host response to Leishmania infection, a factor often overlooked in current models.
Purpose of the Study:
- To develop and optimize an in vivo model for cutaneous leishmaniasis (CL) in the ear dermis of BALB/c mice.
- To evaluate different infection methods, including parasites alone, sand fly bites, or salivary gland sonicate, for Leishmania major.
- To establish a more relevant model for assessing the efficacy of novel antileishmanial drug compounds.
Main Methods:
- BALB/c mice were infected with luciferase-expressing Leishmania major in the ear dermis.
- Infection methods compared: parasites alone, parasites with bites from uninfected Phlebotomus duboscqi sand flies, or with sand fly salivary gland sonicate.
- Parasite load was monitored via bioluminescent signal; dermal lesion development and Leishmania Donovan Units in liver and spleen were assessed.
Main Results:
- A dose-response relationship was observed for bioluminescent signal, indicating parasite load.
- Dermal lesion development and parasite burden in the liver and spleen showed clear responses to infection methods.
- The optimized ear dermis infection model demonstrated sensitivity to infection parameters.
Conclusions:
- The developed in vivo Leishmania major ear infection model offers a more suitable platform for evaluating antileishmanial drug efficacy.
- This model addresses limitations of previous CL models by incorporating relevant infection dynamics.
- Further optimization of this model can facilitate the discovery and development of effective treatments for cutaneous leishmaniasis.
