NEB Exam Q: Leishmaniasis - Types - Diagnosis | Microbiology

Leishmaniasis


A tropical and subtropical disease caused by leishmania and transmitted by the bite of sandflies. It affects either the skin or the internal organs.


Types of Leishmaniasis


There are two main forms of Leishmaniasis. Different species of Leishmania are associated with each form. About 30 Leishmania species have been defined. At least 20 of these are thought to cause disease in mammals.


Visceral Leishmaniasis


Visceral leishmaniasis is sometimes called systemic leishmaniasis. It usually occurs two to eight months after a sandfly bite. It damages the internal organs, such as the spleen and liver. It also affects the immune system, through damage to those organs. The condition is almost always fatal if not treated.


Cutaneous Leishmaniasis


Cutaneous leishmaniasis only causes ulcers on the skin. It is the most common form of leishmaniasis. Treatment may not always be necessary. However, it can speed healing and prevent complications.


Mucocutaneous Leishmaniasis


A third, rare form of the disease is called mucocutaneous leishmaniasis. It can occur several months after skin ulcers heal. This type of leishmaniasis affects the mucous membranes of the nose and palate. It is usually considered a subset of cutaneous leishmaniasis. However, it is more serious. It does not heal on its own. It always requires treatment.


What Are the Symptoms of Leishmaniasis?


People can carry some species of Leishmania for long periods without becoming ill. Symptoms depend on the form of the disease.


Cutaneous Leishmaniasis


The main symptom of this condition is painless skin ulcers. Cutaneous symptoms may appear only one to two weeks after the sand-fly bite. However, sometimes symptoms will not appear for months or years.


In people with mucocutaneous disease, symptoms usually appear one to five years after skin lesions have healed. These are primarily ulcers in the mouth and nose or on the lips. Other symptoms may include:


Stuffy or runny nose


Nose bleeds


Difficulty breathing


Visceral Leishmaniasis


Symptoms often do not appear for months after the bite. Most cases are detected two to six months after infection.


Symptoms include:


Weight loss


Weakness


Cough


A fever that lasts for weeks or months


An enlarged spleen


An enlarged liver


Decreased production of red blood cells (RBCs)


Bleeding


Other infections


Night sweats


Thinning hair


Scaly skin or dark ashen skin


How Is Leishmaniasis Diagnosed?


It is important to tell your doctor if you have lived in or visited a place where leishmaniasis is common. That way your doctor will know to test you for the parasite. If you are found to be infected, other tests will be used to determine which species of Leishmania are causing the disease.


Diagnosing Cutaneous Leishmaniasis


Your doctor may take a small amount of skin for a biopsy. This is done by scraping one of the ulcers. To identify the parasite, the samples may be examined under a microscope or grown in culture. Culture is a way of seeing if there are parasites in a sample. It gives a small amount of parasites the opportunity to grow to detectable levels.


Diagnosing Visceral Leishmaniasis


Many times, people do not remember a sand-fly bite or skin sore. Therefore, this condition may be hard to diagnose.


A doctor may first perform a physical exam to look for an enlarged spleen or liver. Then a bone marrow biopsy or blood sample may be taken for examination. These samples will be checked for the parasite. Diagnosis may take two to four weeks if culture is required.


Lab-Diagnosis:


1. Detection of amastigotes in bone marrow, spleen, or lymph node biopsy.


2. Serologic test.


3. Very high level of serum IgG is indication of infection.


4. Skin test is also available.

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