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Updated: Aug 19, 2026

06:57
In Vivo Infection with Leishmania amazonensis to Evaluate Parasite Virulence in Mice
Published on: February 20, 2020
Visceral leishmaniasis presenting as fever of unknown origin
Abstract:
A 41-year-old male presented with a prolonged febrile disease with marked splenomegaly. Bone marrow and liver biopsy smears and cultures for Leishmania were repeatedly negative and there was no hyperglobulinemia. Leishmania parasites were ultimately demonstrated only in the spleen at laparotomy, performed because of severe pancytopenia. The epidemiology of leishmaniasis in Israel is reviewed.
Related Concept Videos
Increased Body Temperature
A body temperature above 38°C (100.4 °F) is known as fever or pyrexia, and a person with fever is termed 'febrile.' Typically, the hypothalamus, a part of the brain that acts as the body's thermostat, regulates body temperature through a thermoregulatory setpoint. It receives signals from cold and warm thermal receptors throughout the body and adjusts the body's temperature accordingly. Fever occurs when this hypothalamic setpoint is altered, usually in response to an infection or illness.
Types of Fever
Fever can be triggered by several factors, including infections, nervous system disorders, certain cancers, blood diseases like leukemia, embolism, thrombosis, heatstroke, dehydration, surgical trauma, crushing injuries, and allergic reactions.
Here are the different types of fever:
Here are the different types of fever:
Patterns of Fever
Before understanding the types and patterns of fever, it is essential to know its phases.
Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever (RMSF) is a severe tick-borne illness caused by Rickettsia rickettsii, a Gram-negative, coccobacillary bacterium. This pathogen is an obligate intracellular parasite, requiring a host cell for replication. Transmission occurs through the bite of an infected tick. In the United States, the most important vectors are Dermacentor variabilis (American dog tick) and Dermacentor andersoni (Rocky Mountain wood tick), though other tick species may also serve as vectors.
Yellow Fever
Yellow fever is a viral hemorrhagic disease caused by the yellow fever virus (YFV), a member of the Flaviviridae family. It is transmitted primarily by Aedes and Haemagogus mosquitoes in tropical and subtropical regions of Africa and South America. After transmission through a mosquito bite, the virus initially replicates in skin-resident immune cells such as dendritic cells and macrophages. These cells then migrate to the lymph nodes, where viral replication increases, eventually leading to...
Leishmaniasis
Leishmaniasis is a protozoal disease caused by species of the genus Leishmania and transmitted through the bite of infected female sandflies. The parasite exists in two principal morphological forms during its life cycle. A sandfly acquires intracellular amastigotes from an infected reservoir host, such as a dog. Within the sandfly, these forms differentiate into motile, flagellated promastigotes. During a subsequent blood meal, promastigotes are injected into the human host, where they...

