primate assay data sheet
Malaria
Test codes:
X0014
-
Ultrasensitive qualitative screen for
Plasmodium species
by real time PCR. This assay detects but does not differentiate
most malaria-causing
Plasmodium species, including
P. falciparum, P. malariae, P.
vivax,
P. ovale,
P. knowlesi, P. fieldi, P. hylobati, P. juxtanucleare, P.
yoelii, P. brasilianum, P. cynomolgi, P. inui, P.
schwetzi, P. reichenowi, P. eyles, P.jefferyi, P. youngi, P.
pitheci, P. silvaticum, P. coatneyi, P. fragile, P. simiovale,
P. gonderi,
P. simium, P. cathemerium, P.
gallinaceum, P. elongatum, and P.
relictum.
X0012
-
Ultrasensitive qualitative detection of
Plasmodium inui by
real time PCR. This assay does not detect other
Plasmodium species.
Malaria in
primates is caused by protozoan parasites of the genus
Plasmodium. The parasites are transmitted by infected
Anopheles
mosquitos. As
the infected female mosquito takes a blood meal, it injects the
parasite, which travels in the bloodstream to the liver. Inside
the liver, the organism undergoes several developmental changes
leading to the release of a large number of merozoites. These
merozoites invade the red blood cells. The asexual stages often
seen in blood films are young trophozoites (also known as “ring
forms”), mature trophozoites, and the dividing schizonts that
yield the merozoites for a new generation. The liver then acts
as a reservoir from which periodic bouts of parasitemia may
emanate.
Species of
Plasmodium that infect old world primates include P.
schwetzi, P. reichenowi, P. eyles, P.jefferyi, P. youngi, P.
hylobati, P. pitheci, P. silvaticum, P. cynomolgi, P. inui, P.
fieldi, P. coatneyi, P. knowlesi, P. fragile, P. simiovale
and P. gonderi (Cogswell, 2000). In New World monkeys,
only P. brasilianum and P. simium have been
detected. Monkeys infected with these parasites are usually
subclinical, making identification of carriers extremely
difficult. Only when carriers are immunosuppressed or
splenectomized will they develop jaundice, anorexia,
listlessness, fever and anemia.
Splenomegaly may occur in immunosuppressed spleen-intact
animals. Parasitemia in infected animals can fluctuate
dramatically over short periods, so Plasmodium
screening should be performed at multiple time
points. In particular, stress or other immune-suppressive events
may trigger an increase in parasitemia from previously
undetectable levels. Therefore it is ideal when feasible to
screen using liver or spleen biopsy, because the titer of
Plasmodium organisms is more consistently detectable in
these tissues than in peripheral blood.
Traditionally, malaria screening and diagnosis relied on
microscopic examination of blood smears. This method is fast and
cheap but has a very low sensitivity. Successful detection in
blood smears also depends on collecting the specimen at the peak
of the parasitemia. Antibody detection can be used to diagnose
the disease but paired serum samples several weeks apart are
required in order to identify actively infected animals, making
rapid diagnosis impossible. Furthermore, most serology testing
currently available targets the Plasmodium species that
infect humans, such as P. malariae, P. falciparum, P. vivax
and P. ovale. Reagents used for these human serology tests
are not appropriate for screening nonhuman primates. Molecular
detection by PCR is a rapid, specific and sensitive method for
accurately diagnosing and identifying carriers.
Utilities:
-
Help confirm the disease causing agent
-
Help ensure that animal colonies are free of malaria
-
Early prevention of spread of malaria among a colony
-
Minimize personnel exposure to malaria
-
Safety monitoring of biological products and vaccines
that derive from primates
References:
Cogswell, F.B. (2000) Malaria and Piroplasms of non-human
primates. In: Companion and Exotic Animal Parasitology, Bowman
D.D. (Ed). A0304.0600.
Preferred specimen:
0.2 ml liver or spleen tissue.
Less preferred specimen: 0.2 ml whole blood in EDTA (purple top) tube.
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