wildlife and zoo assay data sheet
Monkeypox
Test code:
S0025 - Qualitative detection of monkeypox virus (MPV) by
polymerase chain reaction
Monkeypox
virus (MPV) is an orthopoxvirus that is genetically distinct
from other members of the Poxviridae family, including the
variola, vaccinia, ectromelia, camelpox, and cowpox viruses. It
was first identified as the cause of a pox-like illness in
captive monkeys at the State Serum Institute in Copenhagen in
1958. Currently, MPV is regarded as the most important
orthopoxvirus infection in human beings since the eradication of
smallpox. By contrast with variola virus, however, MPV has a
wide range of hosts, which has allowed it to maintain a
reservoir in wild animals while sporadically causing human
disease, and has precluded its global eradication by human
vaccination.
Serological
surveys suggest that many animals are infected with MPV under
natural conditions, including squirrels, non-human primates, and
rats. After 1997, human monkeypox attracted little attention
worldwide until May, 2003, when the CDC received reports from
the central USA of patients who developed fever and a rash after
close contact with pet prairie dogs and other mammals. This
outbreak, with a total of 81 identified cases (40% laboratory
confirmed), was due to human monkeypox, a disease that had
previously never been recorded in the western hemisphere.
Traceback investigations identified an international shipment of
about 800 small mammals from Ghana to Texas as the probable
source for the introduction of MPV into the USA. Gambian giant
rats from this shipment were transported from Texas via an Iowa
animal vendor to a pet distributor in the Chicago area, where
they were co- LOCATED with prairie dogs (Cynomus spp). Infected
prairie dogs were subsequently transported from the distributor
to a vendor in Wisconsin, where they were sold to the index
patient and others. Infected prairie dogs, which through a
non-linear chain of distribution may have also been sold at
"swap meets" in Illinois, Indiana, and Ohio, have been
implicated as the source of primary infection for most of the US
cases.
Although
virus isolation can be used to diagnose monkeypox virus
infection, a long incubation period is required to obtain
results. Viral culture also increases the potential risk of
laboratory personnel contacting this virus. Furthermore, viral
culture is less sensitive, reliable and specific than polymerase
chain reaction (PCR)-based techniques. Serological testing for
MPVantigens is difficult because of the close antigenic relation
between surface antigens among the orthopoxviruses. Various
serological methods are available, including a virus-neutralising
test with hyperimmune reference sera, a haemagglutination-inhibition
assay with chicken erythrocytes, and detection of specific viral
antibodies. The sensitivities of these tests vary (50–95%),
however, and serological tests are not useful for the diagnosis
of acute infection. Expert opinion is that no serological assay
currently available can reliably diagnose orthopoxvirus
infections with high sensitivity.
Monkeypox
detection by PCR is the most rapid, sensitive and specific
method for the diagnosis of this infection.
Utilities:
-
Help confirm the disease causing agent
-
Help ensure that animal groups and populations are free of
MPV
-
Early prevention of spread of this virus among a
population
-
Minimize human exposure to this virus
Specimen requirement:
Lesion scab or vesicle fluid swab.
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
Methodologies:
Qualitative PCR
Normal range:
Nondetected