Effect of Ambient Temperature on the Clinical Manifestations of Experimental Diffuse Cutaneous Leishmaniasis in a Rodent Model

Abstract

Dermal species of Leishmania have a relatively broad temperature range for optimal growth in vitro, with temperature differences accompanied by a form change. This suggests that when the host is living in moderate temperatures (22°C), infection may proceed at temperatures lower than those that occur in tropical regions (32°C), and a different clinical expression of the disease due to a different parasitic form may result. The aim of this study was to investigate the effect of environmental temperature on the clinical expression of the disease. BALB/C mice infected with Leishmania mexicana were housed at 32°±2°C or 22°±1°C, and assessed for the development of inflammation and the presence of parasites in organs using PCR and immunohistology. The clinical expression of leishmaniasis at 32°C included inflammation at the site of inoculation with swelling of the nose and tail, whereas at 22°C, up to 50% of the infected mice developed dry exfoliative dermatitis with alopecia on the dorsum. In both cases, parasite colonization was confirmed in the skin, with parasites at more external locations at 22°C. Parasite visceralization was confirmed in all internal organs and glands in both cases based on PCR and immunohistology. In conclusion, the clinical expression of diffuse leishmaniasis by Leishmania mexicana in laboratory mice is modified by temperature, from nodular inflammation at 32°C, to dry exfoliative dermatitis and alopecia at 22°C, with parasite visceralization in both cases.

A Review: The Current In Vivo Models for the Discovery and Utility of New Anti-leishmanial Drugs Targeting Cutaneous Leishmaniasis

“…These variables involve methods in the administration of the disease and affect phenotypes, such as modular or ulcerative lesions and fast or slow development of disease. These variables, including parasite dose [ 74 ], site of inoculation [ 75 ], co-injection with sandfly saliva [ 76 ], and temperature [ 77 ], have all been shown to affect disease outcome in animal models, thus demonstrating the importance of mimicking the natural route of infection in all animal models.…”

An investigation of the effects of environmental and ecologic factors on cutaneous leishmaniasis in the old world: a systematic review study

“…The effect of the time lag of temperature is related to the average incubation period of CL 17. Other studies have also ended up with the same results observing a significant positive correlation between the prevalence of CL and the temperature, such as Ali-Akbarpour et al's study in 2012 in different regions of Iran [32] and other countries [26,31,[33][34][35] as well as Roger et al' study in 2013 in Cayenne, French Guiana, 15 with lags of 4-8 months due to the incubation period of CL. Other studies have reported that an increase in temperature can rise the trend of CL cases [15,19,27,[36][37][38][39], and the morbidity of the disease starts in March and reaches its peak in July.…”

Environmental risk modelling and potential sand fly vectors of cutaneous leishmaniasis in Chitral district: a leishmanial focal point of mount Tirich Mir, Pakistan

“…Association patterns of CL and sand fly abundance with climate change events like ENSO have been shown in many parts of the world . In addition, temperature is an important factor in regulating the morphogenesis and growth of disease parasite .…”