Kala-Azar is a condition caused due to leishmania parasite infections. It may affect the internal organs like the liver, spleen, liver, and bone marrow. Some people with leishmania infection have no symptoms. Others may show symptoms like fever, swelling of the spleen & liver, and weight loss.
Post-Kala-Azar Dermal Leishmaniasis (PKDL)
Post-Kala-Azar Dermal Leishmaniasis is a type of infection in which Leishmania invade skin cells. The invaded parasite grows there and shows symptoms like dermal lesions.
Symptoms of Kala- Azar infection
- Intermittent or remittent fever with often higher temperatures in later high-temperature cycles
- Loss of appetite
- Weight loss with progressive emaciation
- Dry, thin, and scaly skin
- Loss of hair
- Grayish discoloration of the skin of feet, hands, face, and abdomen (that is why called Kala-Azar or “Black fever”)
- Splenomegaly or spleen enlargement
- Hepatomegaly or liver – enlargement
Causes of Kala- Azar
Kala-Azar is a vector-transmitted disease. The vector responsible for transmission is sandfly or Phlebotomus argentipes. Sandfly is an insect less than one-fourth of the mosquito size, ranging from 1.5 to 3.5 mm. Sandfly breeds in areas with the following conditions:
- High relative humidity
- Warm temperatures
- High subsoil water
- An abundance of vegetation that serves as nutrition for proliferating larvae
They rapidly grow in these favorable conditions. Sandflies need moisture to thrive and cannot survive dry conditions.
Diagnosis of Kala- Azar
- A detailed history of the patient:
When the patient comes with a history of fever for more than two weeks, not responding to antibiotics.
- Laboratory Tests:
a. Clinical laboratory:
- The patient may show
- Anemia (decrease in red blood cells)
- Progressive leucopenia (decrease in levels of white blood cells)
- Thrombocytopenia (decrease in platelets)
b. Serology tests:
There are a variety of serology tests available for diagnosing Kala-azar. These tests use principles of relative sensitivity, specificity, and operational feasibility.
Some serological tests for diagnosing Kala-Azar include:
- the Direct Agglutination Test (DAT)
- rk39 dipstick
These tests detect the presence of long-lasting IgG antibodies. One more serological test is the non-specific aldehyde test.
IgM detecting tests for Kala-Azar are still under-development.
c. Confirmatory Tests: Parasite demonstration in the following may confirm the infection:
- Bone marrow aspiration
- Spleen aspiration
- Lymph node aspiration
- Culture medium
The sensitivity of the tests varies with the organ aspirated. The spleen aspiration test has the highest specificity and sensitivity.
Why diagnosing Kala- Azar is a challenge?
Kala- Azar diagnosis is challenging for healthcare professionals. The confirmatory diagnosis of Kala-Azar is through tissue specimens. The pathologist gets these tissue specimens by organ needle aspiration. The pathologist examines these aspirates under a microscope for amastigote formation in stained smears. The tissues commonly used for samples are bone marrow, spleen, and lymph nodes. (in some regions) are the tissues most often sampled in patients with suspected infection. The specificity and sensitivity of splenic aspiration are highest (95% – 98%). But this aspiration is risky and may cause bleeding during the procedure. The sensitivity of bone marrow aspirate examination is lower (53% – 95%). All these tissue aspiration procedures need an accurate smear examination and technical skills unavailable in all healthcare facilities, particularly in rural areas.
Prevention of Kala-Azar
Prevention is the best cure for Kala- Azar. Since no vaccine or preventive drug is available for visceral leishmaniasis, protection from sand fly bites is the single most effective measure against this infection.
There are various ways to prevent yourself from Kala- Azar mosquito bites, such as:
- Sand flies are generally most active from dusk to dawn. It is better to avoid during this time.
- If you are outdoor, it is better to have minimal skin exposure. Try to wear long-sleeved shirts and long pants.
- Use insect repellent creams on exposed skin parts. The most effective repellents against sandflies are the ones that contain a chemical called DEET (N, N–diethylmetatoluamide).
- It is better to stay in air-conditioned or adequately screened areas.
- Use proper nets with smaller holes since sand flies being smaller than mosquitoes, can penetrate through smaller holes
- Regularly spray your house with an insecticide to kill sand flies.
- Always soak or spray with a pyrethroid-containing insecticide. Use can also apply pyrethroid-containing insecticide to your bed sheets, curtains, and clothes.
Kala-Azar is a dangerous disease. It is difficult to diagnose. There are no vaccines or preventive medications against it. But adopting simple changes in our lifestyle can prevent us from this disease.