Which of the following infection is diagnosed by aldehyde test?

Formol-gel test or (Napier's aldehyde test) and Chopra's antimony test are useful in the diagnosis of chronic kala-azar. The gel-test is performed by the addition of two drops of commercial formalin to 2 ml of patient's serum in a test tube; the mixture is shaken and allowed to stand at room temperature. If there is opacification and solidification of the serum within 20 minutes, it denotes a positive reaction. It often occurs within a month or two after having the disease. Other lab findings of Leishmaniasis for its diagnosis: Progressive leukopenia with mononuclear increase is most characteristic Demonstration of the parasite in the peripheral blood, spleen, liver, or bone marrow is diagnostic The complement fixation test Leishmanian skin test or Montenegro test Ref: Achars Textbook Of Pediatrics By Swarna Rekha Bhat (ed.), 4th edition, Page 309.