The document discusses the life cycle, transmission, signs and symptoms, and treatment of leishmaniasis. It notes that leishmania parasites infect and divide within macrophages, and are transmitted between a vertebrate host (where they exist as amastigotes) and sandfly vectors (where they exist as promastigotes). Kala-azar symptoms include fever, weight loss, anemia and enlarged spleen/liver. Treatment involves sodium stibogluconate or miltefosine, and liposomal amphotericin B for treatment failures or post-kala-azar dermal leishmaniasis. Poverty, malnutrition, occupation, population movement and environmental/climate factors can influence transmission

4. Life cycle

5. Epidemiological determinants
Agent factors
AGENTS : The leishmania are intracellular parasites. They infect
and divide within macrophages. At least nineteen different
leishmania parasites have been associated with human infection.
Further, the majority of these offer no cross immunity of one
against the other .
Leishmania donovani is the causative agent of kala-azar (VL); L.
tropica is the causative agent of cutaneous leishmaniasis (oriental
sore); and, L. braziliensis is the causative agent of muco-cutaneous
leishmaniasis
. The life cycle is completed in two different hosts - a vertebrate
and an insect; in the former, it occurs in an amastigote form (called
"leishmania bodies") and in the latter as a flagellated
promastigote.
(b) RESERVOIRS OF INFECTION : There is a variety of animal
reservoirs, e.g., dogs, jackals, foxes, rodents and other mammals.
Indian kala-azar is considered to be a nonzoonotic infection with
man as the sole reservoir. This assumption is based largely on the
absence of evidence

6. Host factors
• (a) AGE: Kala-azar can occur in all age groups including
infants below the age of one year. In India, the peak age is 5
to 9 years
• (b) SEX: Males are affected twice as often as females.
• (c) POPULATION MOVEMENT : Movement of population
(migrants, labourers, tourists) between endemic and non-
endemic areas can result in the spread of infection.
• (d) SOCIO-ECONOMIC STATUS: Kala-azar usually strikes the
poorest of the poor. Poverty increases the risk for kalaazar.
Poor housing and domestic sanitary conditions (e.g. lack of
waste management, open sewerage) may increase sandfly
breeding and resting sites, as well as their access to
humans.
• sleeping outside or on the ground, may increase risk

7. • (e) MALNUTRITION: Diets lacking protein-energy; iron,
vitamin A and zinc increases the risk that an infection will
progress to kalaazar
• (f) OCCUPATION: The disease strongly associates with
occupation. People who work in various farming practices,
forestry, mining and fishing have a great risk of being bitten
by sandflies.
• (g) IMMUNITY : Recovery from kala-azar and oriental sore
gives a lasting immunity. During the active phase of kala-
azar, there is impairment of cell mediated immunity, this is
reflected in the negative skin reaction to leishmanin test.

8. •Environmental factors
• (a) ALTITUDE : Kala-azar is mostly confined to the plains; it does
not occur in altitudes over 2000 feet (600metres).
• (b) SEASON :. Generally there is high prevalence during and after
rains.
• (c) CLIMATE CHANGES : Kala-azar is climate sensitive, and is
strongly affected by changes in rainfall, temperature and
humidity. Global warming and land degradation together affect
the epidemiology of kala-azar in many ways. It can have strong
effects on vector and reservoir hosts by altering their distribution
and influence their survival.
• Drought famine and flood resulting from climate changes can
lead to massive displacement and migration of people to areas
with transmission of kala-azar, and poor nutrition could
compromise their immunity .
• (d) RURAL AREAS : The disease is generally confined to rural
areas, where conditions for the breeding of sandflies readily exist
compared to urban areas.

9. • (e) VECTORS : In India, P. argentipes is a proven vector of
kala-azar. Cutaneous leishmaniasis is transmitted by P.
papatasi and P. sergenti. Sandflies breed in cracks and
crevices in the soil and buildings, tree holes, caves etc.
Overcrowding, ill-ventilation and accumulation of organic
matter in the environment facilitate transmission.
• (f) DEVELOPMENT PROJECTS ; Ironically many
development projects are exposing more people to
leishmaniasis. Forest clearing, and cultivation projects,
large water resource schemes, and colonization and
resettlement programmes are bringing human beings
into areas of high vector and reservoir concentration

10. • Mode of transmission
In India, Kala-azar is transmitted from person to person by the bite
of the female phlebotomine sandfly, P. argentipes which is a highly
anthrophilic species.
Transmission may also take place by contamination of the bite
wound or by contact when the insect is crushed during the act of
feeding.
Cutaneous leishmaniasis is transmitted by P. papatasi and P.
sergenti.
After an infective blood meal, the sandfly becomes infective in 6
to 9 days (extrinsic incubation period). This is the time required for
the development of the parasite in the insect vector.
Transmission of kala-azar has also been recorded by blood
transfusion , and is also possible by contaminated syringes and
needles .
Incubation period
• The incubation period in man is quite variable, generally 1 to 4
months; range is 10 days to 2 years.

11. Signs and symptoms
(Kala azar)

17. Haematological findings
These include progressive leucopenia, anaemia and
reversed albumin-globulin ratio, with greatly increased
IgG. The WBC:RBC ratio is 1:1500 or even 1:2000
(normal 1:750). ESR is increased

23. Treatment
2. SSG and Miltefosine failure
- Liposomal Amphotericin B
(when final results are available
with proven efficacy and safety)
Treatment of PKDL : SSG in usual
dosage for kalaazar could be
given for 120 days- Repeated 3-4
courses of Amphotericin B can be
given in patients failing SSG
treatment.
A new drug namely "Liposomal
Amphotericin B" in dose
of 10 mg, administered
intravenously as a single dose
therapy has been introduced in
the Kala-azar therapy.