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Thermosensitivity patterns of Old vs. New World cutaneous strains of Leishmania growing within mouse peritoneal
Abstract:
Infection of mouse peritoneal macrophages in vitro was used to examine the effect of elevated temperature on the intracellular replication of various strains of Leishmania. Of eight cutaneous strains examined, all grew optimally at 35 degrees C. At 37 degrees C the reduction in growth was most pronounced for the New World cutaneous strains, and at 39 degrees C three of four New World cutaneous strains were completely destroyed whereas all of the L. tropica strains survived and exhibited at least 100% growth after 3 days. The results of these in vitro studies correlate closely with the outcome of heat therapy on two patients with cutaneous disease, suggesting that, in general, cutaneous lesions due to L. tropica strains might be less responsive to heat therapy than lesions due to L. mexicana and related strains.
Insights
Elevated temperatures differentially affect Leishmania parasite growth. New World cutaneous Leishmania strains are more susceptible to heat than Leishmania tropica, suggesting varied responses to heat therapy for cutaneous leishmaniasis.
Area of Science:
- Parasitology
- Immunology
- Infectious Diseases
Background:
- Leishmania parasites cause cutaneous leishmaniasis.
- Heat therapy is a potential treatment for cutaneous leishmaniasis.
- Understanding parasite thermotolerance is crucial for treatment efficacy.
Purpose of the Study:
- To investigate the impact of elevated temperatures on the intracellular replication of various Leishmania strains.
- To compare the thermotolerance of New World cutaneous Leishmania strains with Leishmania tropica.
Main Methods:
- Infection of mouse peritoneal macrophages in vitro with different Leishmania strains.
- Incubation at various temperatures (35°C, 37°C, 39°C).
- Assessment of intracellular parasite replication and survival.
Main Results:
- All eight cutaneous Leishmania strains grew optimally at 35°C.
- Growth reduction was most significant for New World cutaneous strains at 37°C.
- At 39°C, three of four New World strains were destroyed, while L. tropica strains survived and grew.
Conclusions:
- Leishmania tropica strains exhibit greater thermotolerance than New World cutaneous strains.
- In vitro findings suggest differential responses to heat therapy for cutaneous leishmaniasis.
- Lesions caused by L. tropica may be less responsive to heat therapy compared to those caused by L. mexicana and related strains.