Today is our topic of discussion Definition of Kalaazar
Definition of Kalaazar
Definition:
Leishmaniasis is a protozoal disease caused by parasite Leishmania donovani, transmitted to man by the bite of sand fly (female phlebotome).
Kala-azar means black fever; kala (black) and azar (fever).
Situation in Bangladesh:
Incidence of kala-azar in Bangladesh is about 175 per 100,000 per annum with the highest rates in Mymensingh, Pabna, and Tangail. In Mymensingh, currently the average annual incidence is as high as 300/10,000 in the most affected communities.
During the 1960s, it almost disappeared as a result of malaria control activities due to DDT spraying. A resurgence of the disease, including post-kala-azar dermal leishmaniasis (PKDL) was seen in several parts of the country during the late 1970s when large scale use of DDT ceased.
Agent factors:
Agents:
Leishmania donovani (obligate intracellular protozoa within macrophage)
Reservoirs of infection:
Humans are incidental hosts and rodents are reservoir hosts.
Host factors:
Age:
All ages may be affected. Young adults are common victims
Sex:
More in males due to occupational exposure
Population movement:
Between endemic and non-endemic area favour spread.
Socio-economic status:
It usually strikes the poorest of the poor.
Occupation:
Those who are engaged in farming practices, forestry and fishing are at risk.
Immunity:
Cell-mediated, but during active phase, impairment of the cell-mediated immunity.
Environmental factors:
Altitude:
Confined to the plains.
Season:
High prevalence during and after rains.
Rural areas:
Rural areas where the conditions of breeding of sandfly exists.
Vector:
‘Phlebotomus argentipes’. Overcrowding, ill-ventilation and accumulation of organic matter in the environment facilitate transmission. Habits are nocturnal.
Development projects:
Forest clearing, cultivation projects etc. brings human nearer to sandfly areas.
Mode of transmission:
Person-to-person by bite of female sandfly ‘Phlebotomus argentipes’.
Incubation period:
1 to 4 months (10 days to 2 years)
Clinical feature and types of leishmaniasis:
Visceral leishmaniasis –
Serious and potentially fatal if untreated. The features are –
- Fever – low grade and for prolonged duration (more than two weeks) dziddu to alig
- Splenomegally – soft and non-tender b mod bas butslitev el tiom, hab
- Hepatomegally
- Progressive weight loss and anemia (may be pancytopenia)
- Appetite is good with clean tongue and the patient may continue working.
- Blackening of skin: Generally occurs in hands, feet, abdomen and face.
Cutaneous leishmaniasis –
Causes an ulcer at the bite site, which heal in a few months to a year, leaving an unpleasant looking scar.
Post-kalazar dermal leishmaniasis (PKDL):
May develop during or after therapy for Kala-azar or several years after initial treatment, characterized by macules, papules, nodules, and patches mostly in the face. It requires further treatment.
Life cycle of leishmania:
Sandfy inject the infective stage (promastigotes with flagella) during blood meals →→ Promastigote phagocytized by macrophages → Transform into amastigotes (without flagella) → Multiply in infected cells and affect different tissues → Sandfly become infected during blood meals on an infected host containing macrophages with amastigotes → In the sandfly’s gut, the parasite differentiate into promastigotes and multiply → Migrate to the mouth-part for next bite.
LD body:
Macrophages containing amastigote form of parasite is called LD body (Leishman- Donovan body).
Investigations:
- Indirect evidence:
- Blood TC, DC, ESR: Leucopenia or even pancytopenia and increased ESR
- ICT for Kalazar: positive
- DAT for kalazar: positive
Direct evidence:
Demonstration of parasite in stained smears of bone marrow aspirate or splenic puncture
Treatment:
- Inj. Sodium stibogluconate (I/V) – 20 mg/kg daily for 28 days. If relapse, retreated for 2 months with same dose.
- Miltefosine – Oral (not in pregnancy and women of reproductive age not using contraceptive regularly) – 2.5 mg/kg/day for 28 days b grub oslavil ons?
- Amphotericin B-I/V
Complication of kala-azar:
- Pneumonia
- Diarrhoea
- Tuberculosis, causing persistent fever, anaemia, weight loss
- If untreated, death.
Prevention & control measure:
- Early case detection and prompt treatment.
- Vector control – Phlebotomus (sandfly) breeds in moist dirt, cracks, crevices, side of drains, piles of rubbish and all kinds of refuse; keep compounds clean and walls in good condition; dark, moist places ventilated and kept dry; spraying of possible breeding places with DDT.
- Avoiding sleeping on floor.
- Health education as well as poverty alleviation measures.
- In endemic districts, it may be advisable to use a net while sleeping.
- Insect repellent ointments are useful for application to the skin.
Leishmaniasis control programme in Bangladesh
Bangladesh is now running a program against Kala azar with the objective to eliminate the disease by 2015 and with an aim to reduce the cases to less than one case per 10,000 populations in endemic upazila of Bangladesh.
India, Bangladesh and Nepal have expressed a commitment to eliminate Kala azar by 2015. In May 2005, the three countries signed a Memorandum of Understanding (MOU), in Geneva during the World Health Assembly in this regard and a Regional Strategic Plan has been prepared and endorsed by the WHO and partners supporting elimination
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