Parvo virus is a highly contagious virus that mainly affects dogs. It spreads between dogs through contact with their feces. Vaccines can prevent infection but mortality reaches 91% in untreated cases. Parvo virus causes vomiting, diarrhea, and leukopenia in infected dogs. It replicates in actively dividing cells and is shed in feces, vomit, urine, and saliva, making it very stable in the environment.

1. PARVO VIRUS
(PARVOVIRIDAE)
HAZEL JEAN M. LOZADA

2. PARVO VIRUS IS A CONTAGIOUS VIRUS
MAINLY AFFECTING DOGS. IT IS A HIGHLY
CONTAGIOUS AND IS SPREAD FROM DOG TO
DOG BY DIRECT OR INDIRECT CONTACT WITH
THEIR FECES.
PARVO VIRUS
a. Family Parvovoridae (parvus meaning small)
b. Comprises of two subfamilies: Parvovirinae (viruses
of vertebrates) and Densovirinae (viruses of insects)
VACCINES CAN PREVENT THIS INFECTION,
BUT MORTALITY CAN REACH 91% IN UNTREATED
CASES.

3. GENERA:
a. Feline panleukopenia virus- includes canine parvovirus,
mink enteritis virus, raccoon parvovirus, parvoviruses of
rodents and lagomorphs, porcine and chicken
parvoviruses.
b. Erythrovirus- includes human B19, related virus of non-
primates, bovine parvoviruses type 3 and chipmunk
parvovirus.
c. Dependovirus are so called adeno- associated viruses
that are themselves replication defective and do not
cause disease as they are unable to replicate except in
the presence of a helper virus; usually adenovirus.
d. Amdovirus- aleutian mink disease virus
e. Bocavirus- bovine parvovirus and canine minute virus

4. Virion Properties:
Are non-enveloped, 25nm in
diameter and have icosahedral
symmetry. Capsid displays a
number of surface features that
are associated with its
functioning.
includes: hollow cylinder at
each fivefold axis of symmetry
that is sorrounded by a circular,
prominent protrusions around
the threefold axis symmetry,
and in most viruses a
depression at each two fold axis
of symmetry.

5. -The Parvovirus capsid is
composed of a total of 60
protein molecules,
approximately 90% of being VP2
and approximately 10% being
the overlapping but larger VP1
protein.
- Genome consists of a single
molecule of a linear single-
stranded DNA, approximately
4.5 - 5.5 kilobase pairs (kb).

6. - Some Parvoviruses
encapsidate only the negative-
sense DNA strand (canine
prvovirus, minute virus of
mice). Others encapsidate
different proportions of both
negative and positive strands,
so that individual virions of
these viruses may contain
single-stranded DNA of either
polarity.

7. Parvovirus capsid proteins all
contains a central eight-stranded,
antiparallel B-barrel motis; the
strands of beta-barrel are linked
by four extensive loop. These loops
form most of the outer surface of
the virus particle and are
responsible for their receptor
binding, their antigenic properties
and their environmental stability.
- extremely stable at extreme
heat and ph
- are very stable, resisting
60 °C for 60mins and ph of 3 to
ph9

8. RECEPTOR BINDING AT THE PLASMA MEMBRANE
INITIATES VIRAL INFECTION OF SUSCEPTIBLE CELLS
AND VIRION ARE TAKEN UP INTO THE CELL BY
ENDOCYTOSIS
UTILIZATION OF THE TTRANSFERRIN RECEPTOR
PROBABLY ALSO FACILITATES REPLICATION OF
PARVOVIRUS AS IT IS MARKEDLY UPREGULATED ON
PROLIFERATING CELLS.
PARVOVIRUS REPLICATION IS INTIMATELY
ASSOCIATED WITH CELLULAR REPLICATION
BECAUSE VIRUS REPLICATION OCCURS ONLY IN
CELLS THAT PASS THROUGH MITOTIC PHASE.
REPLICATION:

9. Life Cycle of the Parvovirus:

10. EPIDEMIOLOGY
The virus may be acquired by direct contact
with infected dogs or via fomites. Fleas and
humans may act as mechanical vector
vectors.
Virus is shed in feces, vomitis, urine, and saliva,
and is very stable in the environment.
Feline panleukopenia is most common in
kittens infected around time of weaning when
maternal anti-body wanes, but all cats of all
ages are susceptible.
The incubation period is approximately
5days (range 2-10 days) at the onset of
clinical signs, there is a profound
leukopenia(reduced number of WBC)

11. Clinical signs include fever(greater than 40 °C) which
can persist for 24 hours.
Affected kittens are noticeably ataxic when they
become ambulatory around 3 weeks of age (so-
called spastic or wobbly cat syndrome)
Severity of leukopenia is grave when the WBC falls at
1000 cells per mL of blood.
In 3rd to 4th days of illness, at which time there is
lassitude, inappetence, a rough coat and often
repeating vomiting.
A profuse, persistent and frequently bloody diarrhea
may develop at approximately the 3rd or 4th day.
Dehydration from severe malabsorption diarrhea
frequently is a major contributing factor to fatal
infections.

12. After virus enters the oropharynx, initial virus
replication occurs in the pharyngeal
lymphoid tissue.
At necropsy, there may segmental
congestion of the mucosa or petechial
hemorrhage in the bowel serosa, although
gross lesion are often very subtle, even in
severely infected cats.
Histologically marked contraction of villi and
attenuation of the lining epithelium, the
crypts are dilated and distended with
mucus and cell debris.
In fetuses infected during the last 2 weeks
of pregnancy and the first 2 weeks of life,
dramatic lesions are present in the
external granular layer of the cerebellum.
PATHOGENESIS:

13. DIAGNOSIS:
Clinical signs, hematological data and
postmortem findings are characteristic
and sufficient for presumptive diagnosis
of panleukopenia. The usual confirmatory
tests include either antigen-capture
enzyme immunoassay or
immunoflourescence for the detection of
antigen in tissues.
Polymerase chain reaction(PCR) assay
for the detection of viral DNA in feces or
tissue. Virus isolation or
hemagglutination-inhibition assays,
enzyme immunoassay, or indirect
immunoflourescence.

14. IMMUNITY, PREVENTION
AND CONTROL
Presence of high-titer antibody is correlated with
protection against reinfection.
Vaccination is widely practiced, with both inactivated and
live-attenuated virus vaccines are available.
Stability of the virus and the very high rates of virus
excretion result in high levels of environmental
contamination, hence it may be difficult to disinfect
contaminated premises (half cup of bleach mixed in
water with a ratio of 1:30)
Wash hands with soap to kill the virus (non-enveloped
virus)
Organic phenolic or iodine, or glutaraldehyde-based
disinfectants, together with thorough cleaning with
detergent-based cleansers, can also be used in these
circumstances.