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wildlife and zoo assay data sheet
Leishmania donovani
complex
Test code:
X0032
- Ultrasensitive qualitative detection but not differentiation
of
Leishmania donovani
and Leishmania infantum ("Leishmania
donovani complex") by real time PCR.
Leishmaniasis is a vector-borne disease whereby an obligate intracellular
protozoan of the genus
Leishmania is transmitted through a sandfly bite. Approximately 21
of 30 known species of
Leishmania can infect human. These include the
L. donovani complex with 2
species (L. donovani and
L. infantum [also known as
L. chagasi in the New
World]); the L. mexicana
complex with 3 main species (L.
mexicana, L. amazonensis, and L.
venezuelensis); L. tropica;
L. major;
L. aethiopica; and the subgenus
Viannia with 4 main species
(L. (V.) braziliensis,
L. (V.) guyanensis,
L. (V.) panamensis, and
L. (V.) peruviana). These
different Leishmania species
are morphologically indistinguishable, and can only be distinguished
by biochemical or molecular methods.
Among these species, L. donovani
causes the most severe form of the disease in humans. It is
responsible for visceral leishmaniasis or “kala-azar”, when it infects
spleen, liver and bone marrow. The parasite is prevalent throughout
tropical and temperate regions including Africa (mostly in Sudan),
China, India, Nepal, southern Europe, southern Russia and South
America.
Similar to other Leishmania
species, the development of L.
donovani requires two different hosts to complete its life cycle:
human is the definitive host and sandfly is the intermediate host.
Some 70 animal species can be natural reservoir hosts of Leishmania parasites.
Of these reservoir
species, dogs are of particular concern to epidemiologists because
their cohabitation with humans can facilitate transmission of the
disease. Symptomatic leishmaniasis disease can occur in canines,
rodents and some other animal species (World Health Organization,
2014).
Incubation period is generally 3 to 6 months after infection, and in some
cases may be over a year, though in India leishmaniasis incubation can
be as short as 10 days. Infected individuals may develop recurring
high fever, enlargement of spleen and liver, and dark skin
pigmentation. Morphological changes around the facial and abdominal
regions are especially prominent. Skin becomes coarse and hard. Warty
eruptions are common in African infections. In advanced stages,
infected patients become emaciated and anemic. The mortality rate is
high in regions with poor medical facilities.
Diagnosis of L. donovani
complex infection can be conducted by either parasitological or
serological methods. Parasitological identification relies on skillful
microscopic examination of stained splenic aspirate smears obtained
through invasive procedures; the sensitivity and specificity of
serological methods are poor. However, molecular detection by
polymerase chain reaction is rapid, highly specific and sensitive, and
can be performed directly on a small blood sample, thus avoiding
invasive procedures to obtain specimens for diagnosis (Abbasi et al.,
2013).
Utilities:
-
Help confirm the disease causing agent
-
Shorten the time required to confirm a clinical
diagnosis of Leishmania
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Help ensure that animal facilities are free of this
parasite
-
Early prevention of spread of
Leishmania in
a facility or geographic area
-
Minimize human exposure to this parasite
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Safety monitoring of biological products that derive
from susceptible animals
References:
Abbasi, I., Aramin, S., Hailu, A., Shiferaw, W., Kassahun, A., Belay,
S., Jaffe, C. and Warburg, A. (2013) Evaluation of PCR procedures for
detecting and quantifying
Leishmania donovani DNA in large numbers of dried human blood
samples from a visceral leishmaniasis focus in Northern Ethiopia. BMC
Infect. Dis. 13:153.
World Health
Organization, Leishmaniasis Fact Sheet N°375, January 2014
Specimen
requirement: 0.2 ml
EDTA whole blood, or 0.2 ml tissue or bone marrow, or 0.2 ml cell
culture.
Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.
For all
specimen types, if there will be a delay in shipping, or during
very warm weather, refrigerate specimens until shipped and ship
with a cold pack unless more stringent shipping requirements are
specified. Frozen specimens should be shipped so as to remain
frozen in transit. See shipping
instructions for more information.
Turnaround time:
2 business days
Methodology:
Qualitative real time PCR
Normal range:
Nondetected
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