10-PARVOVIRUS Flashcards
(238 cards)
1
Q
What are the simplest DNA animal viruses?
A
Parvoviruses
2
Q
Why do parvoviruses have a small coding capacity in their genome?
A
Because their genome is small and viral replication is dependent on replicating host cells or by helper viruses
3
Q
Which parvovirus is pathogenic in humans?
A
Parvovirus B19
4
Q
What type of cells does Parvovirus B19 have tropism for?
A
Every erythroid progenitor cell
5
Q
What does the term “tropism” mean in virology?
A
The ability of the virus to successfully infect host cells
6
Q
Which specific cells are infected by parvovirus B19?
A
Erythroid progenitor cells from bone marrow and liver
7
Q
What receptor does parvovirus B19 require to enter a cell?
A
P blood antigen receptor or globoside
8
Q
On which cells is the P antigen expressed?
A
Mature erythrocytes; erythroid progenitors; megakaryocytes; endothelial cells; placenta; fetal liver; heart
9
Q
What explains the narrow tissue tropism of B19 virus?
A
The P antigen is only expressed on certain cells such as mature erythrocytes; erythroid progenitors; megakaryocytes; endothelial cells; placenta; fetal liver; and heart
10
Q
Once inside the host cell
A
where does the viral DNA of parvovirus B19 go?
11
Q
What is the shape of the parvovirus virion?
A
Icosahedral
12
Q
How many sides does an icosahedral structure have?
A
20 sides
13
Q
What is each side of an icosahedral structure composed of?
A
Each side is composed of an equilateral triangle
14
Q
How do icosahedral viruses expand their capsid size?
A
By increasing the structural units in each phase
15
Q
Does the parvovirus have an envelope?
A
No; it is non-enveloped
16
Q
What is the diameter range of the parvovirus virion?
A
18 to 26 nm
17
Q
What is the molecular weight of the parvovirus virion?
A
5.5 to 6.2 x 10^6
18
Q
What is the density of the parvovirus virion?
A
1.39 to 1.42 g/cm3
19
Q
How resistant is the parvovirus to inactivation?
A
It is extremely resistant to inactivation
20
Q
At which pH levels is the parvovirus stable?
A
Stable at pH 3 and 9
21
Q
How long and at what temperature can parvovirus resist heat?
A
Resists heat at 56°C for 60 minutes
22
Q
By which agents can parvovirus be inactivated?
A
Formalin; ß-propiolactone; and oxidizing agents
23
Q
What type of genome does parvovirus have?
A
Single stranded DNA
24
Q
Is the parvovirus genome linear or circular?
A
Linear
25
What is the size of the parvovirus genome?
5.6 kb
26
What is the molecular weight of the parvovirus genome?
1.5 to 2.0 x 10^6
27
What is the major capsid protein of parvovirus called?
VP2
28
What is the function of the VP2 protein in parvovirus?
It provides the antireceptor that interacts with the cellular receptor leading to further internalization of the virus
29
What is the minor capsid protein of parvovirus called?
VP1
30
What is a characteristic of the VP1 protein in parvovirus?
It consists of unique and terminal residue
31
32
Which subfamily of Parvoviridae infects vertebrates such as mammals
birds
33
Which subfamily of Parvoviridae infects invertebrates such as insects
crustaceans
34
What is the most common species in the genus Erythrovirus under the subfamily Parvovirinae?
B19 virus (human parvovirus B19)
35
Which virus is classified under the genus Bocavirus in the subfamily Parvovirinae?
Human bocavirus
36
Which viruses are included in the genus Parvovirus under the subfamily Parvovirinae?
Feline panleukopenia virus; Canine parvovirus; Minute virus of mice
37
Which genus in the subfamily Parvovirinae contains members that are defective and depend on a helper virus for replication?
Dependovirus
38
What is an example of a virus in the genus Dependovirus that requires a helper virus for replication?
Adeno-associated virus 2
39
Which virus is classified under the genus Amdovirus in the subfamily Parvovirinae?
Aleutian mink disease virus
40
Which genus and species in the subfamily Densovirinae infects the silkworm Bombyx mori?
Iteravirus; Bombyx mori densovirus (Silkworm pathogen)
41
What is the primary criterion distinguishing the subfamilies Parvovirinae and Densovirinae?
Host range; Parvovirinae infect vertebrates and Densovirinae infect invertebrates
42
How many genera are recognized in the subfamily Parvovirinae according to the ICTV?
Eight genera: Bocaparvovirus; Dependoparvovirus; Erythroparvovirus; Protoparvovirus; Tetraparvovirus; Amdoparvovirus; Aveparvovirus; Copiparvovirus
43
How many genera are recognized in the subfamily Densovirinae according to the ICTV?
Five genera: Ambidensovirus; Brevidensovirus; Hepandensovirus; Iteradensovirus; Penstyldensovirus
44
What is the genome type of all parvoviruses?
Linear single-stranded DNA (ssDNA)
45
What is the typical size range of the parvovirus genome?
4–6 kilobases (kb)
46
What is the structure of the parvovirus virion?
Small
47
What is the replication mechanism of parvoviruses?
Rolling hairpin replication
48
What is the main non-structural protein required for parvovirus replication?
NS1 protein
49
What is the function of the NS1 protein in parvovirus replication?
Acts as a helicase
50
What is the main cellular receptor for human B19 parvovirus entry?
Blood group P antigen (globoside)
51
Which cells express the P antigen required for B19 parvovirus entry?
Mature erythrocytes; erythroid progenitors; megakaryocytes; endothelial cells; placenta; fetal liver; heart
52
What is the co-receptor for B19 parvovirus entry?
α5β1 integrin
53
Which host cells are permissive for B19 parvovirus infection?
Only primary erythroid progenitors
54
Where does parvovirus replication occur within the host cell?
In the nucleus
55
During which phase of the host cell cycle does parvovirus replication occur?
S phase
56
What is the endocytic mechanism by which parvovirus enters the host cell?
Clathrin-mediated endocytosis
57
After endocytosis
how is the parvovirus transported to the nucleus?
58
What is the outcome of parvovirus replication in the host cell?
Viral replication results in cell death
59
How is the single-stranded parvovirus genome converted to double-stranded DNA in the host cell?
By a host cell DNA polymerase in the nucleus; even naked viral nucleic acid is infectious as no special viral polymerases are required
60
Where does transcription of parvovirus genes occur and which enzyme is responsible?
In the nucleus using host RNA polymerase II
61
When does parvovirus transcription initiate during the host cell cycle?
When the host cell enters S phase (synthesis phase)
62
What post-transcriptional processes occur in parvovirus mRNA production?
Splicing events create smaller and larger mRNA classes from primary transcripts
63
Where does translation of parvovirus mRNA occur?
In the cytoplasm
64
Which parvovirus mRNAs encode structural proteins?
Smaller mRNAs
65
Which parvovirus mRNAs encode non-structural proteins?
Larger mRNAs
66
What mechanism replicates the parvovirus genome?
Rolling-hairpin replication (RHR)
67
Which viral protein initiates and terminates rolling-hairpin replication?
NS1 (or Rep in some parvoviruses)
68
What role does NS1 play during genome excision?
Acts as an endonuclease introducing single-strand nicks at replication origins
69
How are parvovirus procapsids formed?
Constructed from structural proteins as empty protein shells
70
How is the viral genome inserted into parvovirus procapsids?
A non-structural helicase unwinds dsDNA so single strands enter during or after capsid assembly
71
What happens to newly synthesized parvovirus ssDNA after replication?
Either converted to dsDNA for transcription/replication or encapsidated into new virions released by cell lysis
72
What cellular condition is essential for autonomous parvovirus replication?
Actively cycling host cells (S phase); otherwise requires helper viruses like adenovirus
73
Which cells are primary targets of B19 parvovirus pathogenesis?
Immature erythroid lineage cells in adult marrow
74
What is the consequence of B19 parvovirus replication in erythroid cells?
Cell death leading to interrupted RBC production
75
Which antibodies are produced against B19 parvovirus?
Virus-specific IgG and IgM
76
What causes persistent B19 parvovirus infections?
Immune deficiencies preventing production of neutralizing antibodies
77
Where is B19 parvovirus found in infected patients?
Blood and respiratory secretions
78
What are the modes of transmission for B19 parvovirus?
Respiratory route; blood transfusions; infected blood products (clotting factors/immunoglobulin); mother-to-fetus
79
Why do hemophilia patients have higher B19 antibody prevalence?
Frequent exposure through blood product transfusions containing the virus
80
What is unknown about parvovirus B19 transmission via blood products?
Minimal infectious dose required for transmission
81
Which human parvovirus is found in respiratory specimens and stool?
Human bocavirus
82
Which animal parvovirus causes intestinal replication and enteritis?
Canine parvovirus type 2 (replicates in intestinal mucosal cells of dogs)
83
What distinguishes human bocavirus pathogenesis?
Unknown pathogenic mechanisms despite detection in respiratory/stool samples
84
How does parvovirus B19 resist inactivation in blood products?
High stability against harsh treatments that inactivate enveloped viruses
85
What cellular receptors are critical for B19 parvovirus entry?
Erythrocyte P antigen (globoside) and α5β1 integrin co-receptor
86
Which host genomic feature enables parvovirus replication?
Terminal hairpin structures acting as self-priming replication origins
87
What happens during rolling-hairpin replication?
NS1 nicks replication origins; host polymerases extend DNA using hairpin-primed strand displacement
88
What is the final replication product before genome excision?
Concatemeric DNA containing multiple genome copies
89
How are individual parvovirus genomes excised from concatemers?
NS1-mediated terminal resolution or asymmetric junction resolution
90
What determines parvovirus genome packaging polarity?
Species-specific replication origin efficiency and strand synthesis preferences
91
Which parvovirus protein has HUH endonuclease and helicase domains?
NS1 (critical for replication initiation and genome excision)
92
What triggers parvovirus mRNA translation into proteins?
Host ribosomes in the cytoplasm after nuclear export of mature transcripts
93
Why do parvoviruses require dividing cells for replication?
They lack enzymes to stimulate resting cells into DNA synthesis (S phase dependence)
94
What happens to host cell nuclei during late parvovirus infection?
Disruption via necrosis/apoptosis releases virions through cell lysis
95
Which parvovirus genus includes adeno-associated viruses requiring helpers?
Dependovirus (e.g.
96
What structural feature enables parvovirus capsid stability?
Non-enveloped T=1 icosahedral symmetry with small diameter (18-26 nm)
97
How does NS1 modulate the host cell cycle?
Arrests cell cycle at G1 phase to promote viral replication
98
What role do microtubules play in parvovirus infection?
Transport endosome-released virions to nuclear pores
99
What prevents non-erythroid cells from supporting B19 replication?
Lack of specific co-receptors and intracellular transcriptional blocking
100
How are parvovirus capsid proteins synthesized?
Translated from spliced mRNAs encoding VP1/VP2 structural proteins
101
What enables parvovirus genome flexibility during replication?
Terminal palindromes refolding into hairpins to redirect replication forks
102
Which clinical feature links parvovirus B19 to fetal complications?
Transplacental transmission causing fetal anemia and hydrops fetalis
103
What diagnostic sample types detect human bocavirus?
Respiratory secretions
104
Why are parvovirus capsids resistant to environmental inactivation?
Non-enveloped structure with stable icosahedral protein shell
105
What cellular process do parvoviruses exploit for genome uncoating?
Nuclear import machinery during microtubule-based transport
106
Which parvovirus protein mediates nuclear entry of the genome?
Capsid proteins interacting with nuclear pore complexes
107
How does NS1 facilitate viral DNA synthesis?
By providing helicase activity to unwind DNA at replication forks
108
What is the role of host DNA polymerases in parvovirus replication?
Extend DNA strands using 3’ hairpin primers and viral/host replication factors
109
Which parvovirus component determines tissue tropism?
Capsid-receptor interactions (e.g.
110
What happens to parvovirus mRNAs before translation?
5’ capping
111
How do parvoviruses overcome host DNA damage responses?
NS1-mediated cell cycle arrest and inhibition of apoptotic pathways
112
What is the significance of parvovirus genome hairpins?
Serve as self-priming origins and replication direction switches during RHR
113
Which host factors assist parvovirus genome conversion to dsDNA?
DNA repair proteins and replication machinery (e.g.
114
Why are parvovirus infections often acute rather than persistent?
Rapid cell lysis and immune clearance in immunocompetent hosts
115
What clinical symptom links B19 to erythema infectiosum?
“Slapped cheek” rash from immune complex-mediated vasculitis
116
How does B19 evade antibody responses in persistent infections?
Antigenic variation and immune suppression in erythroid progenitors
117
What distinguishes autonomous parvoviruses from dependoparvoviruses?
Ability to replicate without helper viruses in cycling cells
118
Which parvovirus protein interacts with host transcription machinery?
NS1’s C-terminal activation domain upregulates viral gene expression
119
What is the role of VP1 unique region in parvovirus infection?
Contains phospholipase A2 activity for endosomal escape
120
How does B19 parvovirus affect erythroid differentiation?
Induces apoptosis in CFU-E progenitors via NS1 cytotoxicity
121
What mechanism prevents parvovirus genome integration?
Lack of integrase and reliance on episomal replication in nuclei
122
Which population is at highest risk of chronic B19 anemia?
Immunocompromised patients (e.g.
123
What is the primary site of B19 replication during pregnancy?
Fetal liver erythroid progenitors leading to severe anemia
124
How does human bocavirus differ clinically from B19?
Associated with respiratory/gastrointestinal symptoms rather than hematologic
125
What enables parvovirus genome packaging into preformed capsids?
Portal complex at one vertex facilitating ssDNA insertion
126
Which cellular compartment stores parvovirus structural proteins?
Nucleus where capsid assembly occurs
127
What triggers parvovirus virion release from host cells?
Lysis due to NS1-induced cytotoxicity and replication stress
128
How does NS1 inhibit host gene expression?
Transcriptional repression and mRNA degradation via nuclease activity
129
What role do parvovirus non-structural proteins play in immune evasion?
Interference with IFN signaling and antigen presentation
130
Which parvovirus feature allows survival in harsh environments?
Heat/pH-resistant capsid lacking lipid envelope
131
How does B19 parvovirus impair erythropoiesis?
Direct cytotoxicity and immune-mediated destruction of erythroid precursors
132
What diagnostic marker confirms acute B19 infection?
IgM antibodies against VP2 capsid protein
133
Which therapeutic approach treats chronic B19 anemia?
Intravenous immunoglobulin (IVIG) providing neutralizing antibodies
134
What epidemiologic trait complicates B19 prevention?
Asymptomatic infections and respiratory transmission before rash onset
135
How does parvovirus NS1 cause DNA damage?
Nicking activity at replication origins and helicase-induced replication stress
136
Which cellular pathway does NS1 activate during infection?
ATM/ATR DNA damage response due to replication fork collapse
137
What is the role of VP2 in parvovirus antigenicity?
Dominant target for neutralizing antibodies due to surface exposure
138
How does B19 parvovirus infect placental cells?
Via P antigen expression on syncytiotrophoblasts
139
What fetal complication requires prenatal B19 diagnosis?
Hydrops fetalis from severe anemia and heart failure
140
Which animal parvovirus model informs B19 research?
Minute virus of mice (MVM) for replication mechanisms
141
What limits parvovirus genome size?
Reliance on host replication machinery and capsid volume constraints
142
How do parvoviruses achieve high mutation rates?
Error-prone replication by host polymerases and lack of proofreading
143
What is the clinical significance of B19 VP1 unique region?
Contains epitopes for neutralizing antibodies and receptor binding
144
Which host factor restricts B19 replication in non-erythroid cells?
Lack of erythroid-specific transcription factors (e.g.
145
How does B19 parvovirus cause arthralgia?
Immune complex deposition in joints triggering inflammation
146
What is the role of microRNAs in parvovirus persistence?
Potential regulation of viral/host gene expression (hypothesized)
147
Which parvovirus feature enables long-term environmental survival?
Non-enveloped capsid resisting desiccation and disinfectants
148
How does NS1 modulate host chromatin?
Remodeling nucleosome positioning to access viral replication origins
149
What is the significance of parvovirus genome terminal palindromes?
Form cruciform structures guiding replication origin nicking
150
Which host enzyme repairs parvovirus nicked DNA?
DNA ligase I/III sealing gaps after NS1 excision
151
How does B19 parvovirus inhibit apoptosis early in infection?
NS1 interaction with pro-survival Bcl-2 proteins
152
What triggers apoptosis late in B19 infection?
Accumulation of NS1 and viral DNA exceeding repair capacity
153
Which parvovirus protein determines host range?
Capsid surface loops mediating receptor binding specificity
154
How do parvoviruses exploit S phase?
Access to nucleotide pools and replication machinery for RHR
155
What is the role of ubiquitination in parvovirus replication?
NS1 hijacks host ubiquitin ligases to degrade antiviral proteins
156
Which immune cells clear parvovirus-infected cells?
Cytotoxic T lymphocytes recognizing NS1/VP epitopes
157
What is the significance of B19 quasi-species?
Antigenic drift potential under immune pressure
158
How does NS1 inhibit interferon response?
Blocking IRF3 activation and STAT1 phosphorylation
159
Which parvovirus vaccine strategy shows promise?
Virus-like particles (VLPs) eliciting VP2-neutralizing antibodies
160
What limits parvovirus oncogenic potential?
Inability to integrate genomes and strict S phase dependence
161
How does B19 parvovirus cause transient aplastic crisis?
Massive erythroid progenitor lysis in marrow
162
Which host factor enhances B19 entry?
α5β1 integrin co-receptor binding after P antigen attachment
163
What is the role of sialic acid in some parvovirus infections?
Alternative receptor for certain animal parvoviruses
164
How does NS1 regulate viral gene expression?
Transcriptional activation via C-terminal domain binding promoters
165
What is the fate of parvovirus-infected stromal cells?
Non-permissive but support erythroid progenitor infection
166
Which syndrome associated with B19 parvovirus presents with a cutaneous rash in children (fifth disease)?
Erythema infectiosum
167
Which syndrome associated with B19 parvovirus presents with arthralgia-arthritis in adults?
Erythema infectiosum
168
Which syndrome associated with B19 parvovirus presents with severe acute anemia in patients with underlying hemolysis?
Transient aplastic crisis
169
Which syndrome associated with B19 parvovirus presents with chronic anemia in patients with immunodeficiencies?
Pure red cell aplasia
170
Which syndrome associated with B19 parvovirus presents with fatal anemia in the fetus?
Hydrops fetalis
171
hat is the most common clinical manifestation of parvovirus B19 infection in humans?
Erythema infectiosum (Fifth Disease)
172
Which cells does parvovirus B19 infect to cause the characteristic rash in erythema infectiosum?
Endothelial cells in blood vessels
173
Why does erythema infectiosum resolve spontaneously?
It is self-limiting due to a Th1-mediated immune response and IgM production
174
What immune mechanism explains the rash and joint symptoms in erythema infectiosum?
Antigen-antibody complex deposition in skin/joints
175
What is the classic facial rash appearance in erythema infectiosum?
"Slapped cheek" appearance with red malar rash
176
Where does the erythema infectiosum rash typically spread after affecting the face?
Arms
177
How long does the erythema infectiosum rash typically last?
2-4 days (may recur for weeks)
178
What is the primary clinical feature of parvovirus B19 infection in adults?
Arthralgia/arthritis (hands and knees most affected)
179
How long can parvovirus-associated arthropathy persist in adults?
Weeks to years (resembles rheumatoid arthritis)
180
What is the incubation period for parvovirus B19 infection?
1-2 weeks (up to 3 weeks)
181
When does viremia occur after parvovirus B19 infection?
1 week post-infection (lasts ~5 days)
182
Where is parvovirus B19 shed during viremia?
Upper respiratory tract (pharynx/nasal secretions)
183
What symptoms appear during the first phase of parvovirus B19 infection?
Flu-like symptoms (fever
184
When do IgG antibodies against parvovirus B19 develop?
~15 days post-infection
185
What percentage of parvovirus B19 infections are asymptomatic?
~25%
186
Why does immunity to parvovirus B19 typically last a lifetime?
Single infection induces durable protective immunity
187
What is the recommended symptomatic treatment for erythema infectiosum?
NSAIDs for pain/fever; antihistamines for pruritus
188
What is transient aplastic crisis (TAC) in parvovirus B19 infection?
Temporary cessation of RBC production causing severe anemia
189
Which patients are most susceptible to transient aplastic crisis?
Those with hemoglobinopathies (e.g.
190
How does parvovirus B19 cause anemia in TAC?
Destroys erythroid precursors via P antigen-mediated infection
191
What are common underlying conditions predisposing to TAC?
Sickle cell disease
192
What complications can occur during transient aplastic crisis?
Pancytopenia
193
How long does recovery from transient aplastic crisis typically take?
2 weeks (with normal RBC precursors)
194
What defines pure red cell aplasia (PRCA) in immunocompromised patients?
Chronic anemia requiring blood transfusions
195
Which patient populations develop parvovirus-associated PRCA?
AIDS
196
What is the fetal risk of maternal parvovirus B19 infection?
Hydrops fetalis and fetal death due to severe anemia
197
Why does parvovirus B19 cause hydrops fetalis?
Fetal erythroid progenitor destruction → anemia → high-output heart failure
198
What mechanism explains fetal liver damage in congenital B19 infection?
Extramedullary erythropoiesis → portal hypertension → hepatocyte damage
199
Does parvovirus B19 cause congenital malformations?
No evidence of physical abnormalities
200
When is maternal-fetal transmission most likely?
High maternal viral load during pregnancy
201
What hematologic changes occur during parvovirus viremia?
Reticulocytopenia (0-1% reticulocytes)
202
Why are TAC patients highly contagious?
High viral shedding during active viremia
203
What isolation precautions are needed for TAC patients?
Respiratory/droplet precautions to prevent transmission
204
What is the detection rate of human bocavirus in respiratory tract samples from young children with respiratory infections?
1.5% to 11.3%
205
In which group is human bocavirus prevalent and often associated with acute wheezing?
Young children
206
Is human bocavirus often found alone or in mixed infections?
Often found in mixed infections with other viruses
207
What percentage of stool samples from children with acute gastroenteritis contain human bocavirus?
About 3%
208
Why is human bocavirus not yet considered a definitive causative agent of acute respiratory disease in children?
Because it is often found in mixed infections and coinfection rates with other enteric pathogens are high
209
What is the most sensitive laboratory test for detecting parvovirus DNA?
Polymerase Chain Reaction (PCR)
210
Which samples can PCR detect parvovirus B19 DNA in?
Serum
211
What is a limitation of PCR testing for parvovirus B19?
It may miss non-B19 strains due to sequence differences
212
Which assay is the only available test for detecting human bocavirus?
PCR
213
In which sample types is bocavirus DNA detected?
Serum
214
What do serological assays for parvovirus B19 detect?
Antibodies against recombinant parvovirus B19 antigens
215
What does detection of B19 IgM antibody indicate?
Recent infection within 2-3 months
216
When do B19 IgG antibodies against conformational epitopes on VP1 and VP2 typically appear?
Around 4 years of age
217
Why might antibodies not be detected in immunodeficient patients with chronic B19 infections?
Because they may fail to produce antibodies; diagnosis relies on viral DNA detection
218
What other diagnostic methods can identify parvovirus B19?
Antigen detection assays and immunohistochemistry in bone marrow
219
Is virus isolation commonly used for parvovirus B19 or bocavirus?
No
220
In which age groups does parvovirus B19 infection occur?
All age groups
221
Where do parvovirus B19 outbreaks most commonly occur?
Schools
222
At what ages do most people develop antibodies to parvovirus B19?
Between 5 and 19 years
223
What percentage of adults and elderly people are seropositive for parvovirus B19?
60% of adults and 90% of elderly people
224
Where has bocavirus been found globally?
In young children worldwide
225
What is the main mode of transmission for parvovirus B19?
Respiratory tract via respiratory secretions during viremia
226
How does parvovirus B19 spread through respiratory secretions?
Through coughing
227
What environmental factor contributes to parvovirus transmission in schools and daycare centers?
Virus stability on contaminated surfaces
228
Who is the common source of maternal parvovirus B19 infection during pregnancy?
The mother’s older child
229
What fetal complications can result from maternal parvovirus B19 infection?
Fetal anemia
230
Can parvovirus B19 be transmitted by blood transfusions?
Yes
231
What is the main treatment approach for parvovirus infections?
Supportive care and symptom management
232
Which parvovirus-related conditions are treated symptomatically?
Fifth disease and transient aplastic crisis
233
When is transfusion therapy indicated in parvovirus infection?
In cases of severe anemia
234
What is the role of commercial immunoglobulin preparations in parvovirus B19 infection?
They contain neutralizing antibodies and help treat persistent infections in immunocompromised patients
235
Is there a specific treatment for human bocavirus infections?
No
236
Are vaccines or antiviral drugs available for parvovirus B19 or bocavirus?
No vaccines or antiviral drugs are currently available
237
What preventive measures help reduce parvovirus transmission?
Good hygiene (hand washing
238
What general advice helps prevent respiratory virus spread?
Covering mouth and nose when coughing or sneezing
