Likewise, patients with abnormal immune systems (e.g., HIV infection) will have false-negative tests.Other tests being developed include detects erythrosalicylic acid. Prevention
As of 2018, there are no vaccines or preventive drugs for visceral leishmaniasis, but vaccines are in development. The most effective method to prevent infection is to protect from sand fly bites. To decrease the risk of being bitten, these precautionary measures are suggested:
Outdoors:1. Avoid outdoor activities, especially from dusk to dawn, when sand flies generally are the most active. 2. When outdoors (or in unprotected quarters), minimize the amount of exposed (uncovered) skin to the extent that is tolerable in the climate. Wear long-sleeved shirts, long pants, and socks; and tuck your shirt into your pants. 3. Apply insect repellent to exposed skin and under the ends of sleeves and pant legs. Follow the instructions on the label of the repellent. The most effective repellents generally are those that contain the chemical DEET (N,N-diethylmetatoluamide). Indoors:1. Stay in well-screened or air-conditioned areas. 2. Keep in mind that sand flies are much smaller than mosquitoes and therefore can get through smaller holes. 3. Spray living/sleeping areas with an insecticide to kill insects. 4. If you are not sleeping in a well-screened or air-conditioned area, use a bed net and tuck it under your mattress. If possible, use a bed net that has been soaked in or sprayed with a pyrethroid-containing insecticide. The same treatment can be applied to screens, curtains, sheets, and clothing (clothing should be retreated after five washings)."
L. donovani itself is not usually the direct cause of death in people with kala-azar, however. Pneumonia, tuberculosis, and dysentery are omnipresent in the immuno-depressed regions where leishmaniasis thrives, and, as with AIDS, it is these opportunistic infections that are more likely to kill, flaring up in a host whose immune system has been weakened by the L. donovani infection. Progress of the disease is extremely variable, taking anywhere from one to twenty weeks, but a typical duration for the Sudanese strain of the disease is narrower, between twelve and sixteen weeks.Even with recovery, kala-azar does not always leave its hosts unmarked. Some time after successful treatment—generally a few months with African kala-azar, or as much as several years with the Indian strain—a secondary form of the disease may set in, called post kala-azar dermal leishmaniasis, or PKDL. This condition manifests first as small, measle-like skin lesions on the face, which gradually increase in size and spread over the body. Eventually the lesions may coalesce to form disfiguring, swollen structures resembling leprosy, and occasionally causing blindness if they spread to the eyes. (This disease is not the same as cutaneous leishmaniasis, a milder disease caused by another protozoan of the Leishmania genus which also causes skin lesions.) Cause
Two species of Leishmania are known to give rise to the visceral form of the disease.