166: Poxvirus Infections Flashcards
(250 cards)
1
Q
What are the main genera of poxviruses that affect humans?
A
The main genera of poxviruses that affect humans include Orthopoxvirus, Parapoxvirus, Mulloscipoxvirus, and Yatapoxvirus.
Examples: Orthopoxvirus includes Variola (smallpox), Vaccinia, Cowpox, and Monkeypox.
2
Q
What is variolation and how did it relate to smallpox prevention?
A
Variolation is the intentional introduction of smallpox virus from a pustule of an infected person into a healthy nonimmune person to induce a mild form of the disease as prophylaxis against a full-scale infection.
3
Q
What are the two main strains of variola virus and how do they differ?
A
The two main strains of variola virus are Variola major and Variola minor. Variola major is more common, severe, and often lethal, while Variola minor is milder and less lethal.
4
Q
What are the clinical features of smallpox during the prodrome phase?
A
During the prodrome phase of smallpox, the clinical features include an asymptomatic incubation period lasting 7-17 days, high fever (39-41°C), chills, myalgia, severe headache, and a duration of 2-3 days.
5
Q
What are the cutaneous findings associated with smallpox?
A
The cutaneous findings associated with smallpox include an enanthem of red macules on the mouth, tongue, and oropharynx that vesiculate and ulcerate, followed by a skin rash that begins as macules on the face and extremities.
6
Q
What is the primary mode of transmission for smallpox?
A
Smallpox is primarily transmitted via respiratory droplets and requires close contact. Factors influencing its spread include aerosol spread, seasonal outbreaks, and high population density.
7
Q
What are the clinical features of smallpox during the prodromal phase?
A
During the prodromal phase of smallpox, the clinical features include an asymptomatic incubation period lasting 7-17 days, high fever (39-41°C), chills, myalgia, severe headache, and a duration of 2-3 days.
8
Q
Describe the cutaneous findings associated with smallpox and their timeline.
A
The cutaneous findings associated with smallpox include an enanthem of red macules on the mouth, tongue, and oropharynx developing 1 day after fever onset, followed by a skin rash starting a day later.
9
Q
What historical practice involved the intentional introduction of smallpox virus?
A
The historical practice known as variolation involved the intentional introduction of smallpox virus from a pustule of an infected person into a healthy nonimmune person to induce a mild form of the disease.
10
Q
What was the significance of the first vaccine developed in 1796 in relation to smallpox?
A
The first vaccine developed in 1796 involved inoculating patients with cowpox virus to protect them against smallpox virus, marking the beginning of vaccination efforts that led to the eradication of smallpox.
11
Q
What are the implications of the discovery of a misplaced vial of variola virus in 2014?
A
The discovery of a misplaced vial of variola virus in 2014 raised concerns about the potential existence of other unreported stocks of the virus, suggesting risks for public health and biosecurity.
12
Q
How does the susceptibility to smallpox vary among different populations?
A
Susceptibility to smallpox varies among populations, with the very young, elderly, and pregnant women being more susceptible.
13
Q
What are the adverse effects associated with the smallpox vaccine?
A
Adverse effects associated with the smallpox vaccine are particularly concerning in immunocompromised patients and individuals with atopic dermatitis or other skin barrier defects.
14
Q
What is the significance of the histopathologic features of poxviral cutaneous lesions?
A
The histopathologic features of poxviral cutaneous lesions, including intracytoplasmic eosinophilic inclusion bodies, are significant for diagnosis and differentiating poxvirus infections.
15
Q
What role does the environment play in the transmission of smallpox?
A
The environment plays a significant role in the transmission of smallpox, with seasonal outbreaks more common in winter and early spring due to favorable conditions for virus survival.
16
Q
What is the likely condition for a patient with suspected smallpox but no rash?
A
The likely condition is variola sine eruption, a brief febrile illness without a rash that can occur in vaccinated individuals exposed to variola major.
17
Q
What form of smallpox might a patient with soft, velvety lesions that coalesce into confluent plaques have?
A
This might be flat smallpox (malignant smallpox), characterized by soft, velvety lesions that coalesce into confluent plaques.
18
Q
What are the key characteristics of lesions in variola major?
A
Lesions in variola major progress synchronously, with macules turning to papules, then vesicles, and finally pustules, with all stages lasting 1-2 days.
19
Q
What are the different forms of variola major and their characteristics?
A
Forms of variola major include Modified smallpox (mild, nonfatal), Flat smallpox (uncommon, high mortality), Hemorrhagic smallpox (rarest and deadliest), Variola sine eruption (brief febrile illness), and Variola minor infection (milder strain).
20
Q
What are the noncutaneous findings associated with variola major?
A
Noncutaneous findings associated with variola major include arthritis, osteomyelitis variolosa, swelling of eyelids, cough, bronchitis, encephalopathy, and gross hematuria in the hemorrhagic type.
21
Q
What is the transmission process of the variola virus?
A
Variola virus spreads by implantation of droplets onto mucous membranes, accidental inoculation into the skin, aerosolization of viral particles, and remains transmissible until all scabs have fallen off.
22
Q
What are the diagnostic criteria for smallpox?
A
An acute, generalized rash with characteristic well-circumscribed, firm, deep-seated vesicles or pustules should raise concern for smallpox.
23
Q
What are the key characteristics of the lesions associated with variola major?
A
Lesions progress synchronously, with macules turning to papules, then vesicles, and finally pustules, with all stages lasting 1-2 days.
24
Q
What are the complications associated with variola major?
A
Complications include secondary bacterial infections, keratitis, respiratory complications, limb deformities, orchitis, and encephalitis.
25
What is the CDC protocol for evaluating acute, generalized rash that raises concern for smallpox?
The evaluation includes assessing an acute, generalized rash with characteristic well-circumscribed, firm, deep-seated vesicles or pustules.
26
What is the clinical significance of the pitted scars associated with smallpox survivors?
Pitted scars, known as 'pock-marks', occur in 65-80% of survivors, primarily affecting the face and are disfiguring.
27
What is the role of PCR in the diagnosis of smallpox?
PCR can differentiate between minor and major strains of smallpox, aiding in diagnosis and understanding disease severity.
28
What are the characteristics of variola sine eruption?
Variola sine eruption is characterized by a brief febrile illness without a rash, occurring in vaccinated individuals exposed to variola major.
29
What are the implications of the hemorrhagic forms of smallpox?
The early hemorrhagic form shows massive hemorrhage before rash development, leading to death, while the late form occurs after rash onset.
30
What steps should you take to assess the risk of smallpox in a patient with a vesicular rash and febrile prodrome?
Assess the patient's history, exposure to smallpox, and follow the CDC protocol for evaluation of acute, generalized rash.
31
What are the implications of the hemorrhagic forms of smallpox?
The early hemorrhagic form shows massive hemorrhage from mucosal surfaces before any rash develops, leading to death before the 6th day of illness. The late hemorrhagic form occurs after the onset of a typical rash, with death occurring within 12 days, affecting both men and women equally.
32
What steps should you take to assess the risk of smallpox in a patient with a vesicular rash and febrile prodrome?
1. Implement airborne and contact precautions immediately. 2. Evaluate the patient using the CDC's major and minor smallpox criteria. 3. Determine the risk level: HIGH (all major criteria met), MODERATE (febrile prodrome + 1 major or 4+ minor criteria), or LOW (febrile prodrome + fewer than 4 minor criteria or no febrile prodrome).
33
What is the next step in management for a patient who meets all major criteria for smallpox suspicion?
Contact the local and state health department immediately. They will coordinate diagnosis and management efforts with the CDC.
34
What diagnosis should you consider if a patient with suspected smallpox has lesions in different stages of development?
Consider chickenpox, as its lesions are more superficial, appear in crops, and are in multiple stages of development simultaneously.
35
What is the likely diagnosis for a patient with a rash concentrated on the face and distal extremities, with all lesions in the same stage of development?
The likely diagnosis is smallpox, as it presents with a centrifugal distribution and lesions in the same stage of development.
36
What form of smallpox might a patient with hemorrhagic lesions and severe thrombocytopenia have?
This might be hemorrhagic smallpox, which is characterized by hemorrhage into the skin or mucous membranes and severe thrombocytopenia.
37
What are the major criteria for defining suspicion of smallpox?
1. Febrile prodrome: 1 to 4 days before rash onset. 2. Classic smallpox lesions: Defined as deep-seated, firm/hard, round, well-circumscribed vesicles or pustules. 3. Lesions in the same stage of development: All vesicles or all pustules on any one part of the body.
38
What are the minor criteria for smallpox suspicion?
1. Centrifugal distribution: Lesions concentrated on the face and distal extremities. 2. Lesions first occurred on the oral mucosa/palate, face, or forearms. 3. Appearance: Patient appears toxic or moribund. 4. Slow evolution of lesions: Evolving from macules to papules to pustules, with each stage lasting 1 to 2 days. 5. Lesions on palms and soles.
39
What laboratory tests are recommended for high-risk smallpox cases?
For high-risk smallpox cases, the following laboratory tests are recommended: 1. All testing should be performed by a biosafety level 3 laboratory. 2. Electron microscopy: Performed under biosafety level 3 conditions. 3. PCR: For variola and other nonvariola Orthopoxvirus, coordinated by the CDC.
40
What are the laboratory abnormalities associated with smallpox?
Laboratory abnormalities associated with smallpox include: - Increased WBC: Observed during the pustular stage. - Severe thrombocytopenia: Seen in hemorrhagic smallpox (early and late forms). - Decrease in factor V: (accelerator globulin) level and increase in thrombin time, indicating early hemorrhagic form. - Late hemorrhagic form: Exhibits a smaller degree of coagulation disturbances.
41
What differentiates chickenpox from smallpox?
Key differences between chickenpox and smallpox include:
| Feature | Chickenpox | Smallpox |
|---------|------------|----------|
| Lesion appearance | More superficial ("dewdrops on a rose petal") | Deep-seated, firm lesions |
| Stages of lesions | Appear in crops and multiple stages at once | All lesions in the same stage |
| Progression | Evolves quickly from macule to papule to vesicle to crust in less than 24 hours | Slower evolution of lesions |
| Disease course | Shorter; all lesions crusting within 4-6 days | Longer disease course |
| Prodrome | Not preceded by significant prodrome | Preceded by febrile prodrome |
42
What should be done when a high-risk smallpox case is identified?
When a high-risk smallpox case is identified, the following actions should be taken: 1. Contact local and state health departments immediately. 2. Lead diagnosis and management efforts in coordination with the CDC. 3. High-risk specimens should be tested only at laboratories with appropriate expertise and biosafety levels.
43
What laboratory tests are recommended for moderate- and low-risk cases of smallpox?
For moderate- and low-risk cases, the following laboratory tests are recommended to rule out more common causes of febrile exanthema: - Tzanck smear (HSV) - Direct fluorescent antibody assay (HSV, VZV) - PCR (HSV, VZV, enterovirus) - Electron microscopy, if possible, to distinguish between poxvirus and VZV. - Biopsy to evaluate for EM. - PCR for variola and other nonvariola Orthopoxvirus (coordinated by CDC).
44
What is the role of real-time PCR (RT-PCR) in the diagnosis of smallpox?
Real-time PCR (RT-PCR) is the quickest and most sensitive assay for detecting and differentiating between orthopoxviruses. It includes: - Orthopoxvirus RT-PCR: Detects all Orthopoxvirus including variola. - Nonvariola Orthopoxvirus RT-PCR: Detects all Orthopoxvirus except for variola. - RT-PCR assay that detects only variola.
45
What are the pathological findings in smallpox lesions?
Pathological findings in smallpox lesions include:
- **Early papules**: Edema and dilatation of capillaries of papillary dermis; perivascular infiltrate of lymphocytes, histiocytes, and plasma cells.
- **Progression**: Epidermal cells become vacuolated and swollen with balloon degeneration.
- **Vesicles**: Contain intracytoplasmic inclusion bodies (Guarnieri bodies).
- **Pustules**: Migration of PMNs into the vesicles.
- **Mucous membrane lesions**: Extensive necrosis of epithelial cells leading to rapid ulceration.
46
What differentiates chickenpox from smallpox in terms of lesion characteristics?
Differentiating characteristics between chickenpox and smallpox include:
| Feature | Smallpox | Chickenpox |
|---------|----------|------------|
| Lesion appearance | Deep-seated, firm, round, well-circumscribed | More superficial, "dewdrops on a rose petal" |
| Stages of lesions | All lesions in the same stage | Multiple stages seen at once |
| Progression | Slower evolution from macule to papule to vesicle | Faster progression from macule to vesicle to crust |
| Disease course | Longer duration | Shorter duration, crusting within 4-6 days |
| Prodrome | Significant prodrome | Not preceded by significant prodrome |
47
What is the recommended approach for high-risk cases of smallpox regarding testing?
For high-risk cases of smallpox, the recommended approach for testing is:
1. **All testing should be performed by a biosafety level 3 laboratory.**
2. **Electron microscopy**: Performed under biosafety level 3 conditions at a local facility.
48
What are the conditions for testing under biosafety level 3?
All other testing should be performed by a Laboratory Research Network facility or by the CDC, including PCR.
49
What should be considered for a patient with a rash and lymphadenopathy after recent travel to an area with monkeypox outbreaks?
Consider human monkeypox, which clinically resembles smallpox but often manifests with lymphadenopathy.
50
What differential diagnoses should be considered for a patient with a rash that includes the palms and soles?
Consider smallpox, secondary syphilis, or other conditions like meningoencephalitis or viral hemorrhagic fevers.
51
How does a history of vaccination affect the risk for a patient with suspected smallpox?
Vaccination provides full protection for 3-5 years and waning immunity for at least another 10 years. Revaccination may provide significant protection for at least 30 years.
52
What should be done for a patient with suspected smallpox who has a history of recent exposure to laboratory handling orthopoxviruses?
Vaccination is indicated for lab workers handling non-highly attenuated orthopoxviruses. If exposure is confirmed, post-exposure vaccination should be administered.
53
What is the role of post-exposure vaccination for a patient with suspected smallpox who has a history of recent exposure to a confirmed case?
Post-exposure vaccination within 2-3 days of exposure can provide protection against severe disease, and within 4-5 days may protect against death.
54
What should be done for a patient with suspected smallpox who has a history of recent exposure to a confirmed case but is severely immunodeficient?
The management for this scenario is not specified in the provided text.
55
What should you do for a patient with suspected smallpox who has a confirmed case but is severely immunodeficient?
Treatment with antiviral therapy is preferred, but there is no absolute contraindication to vaccination during an outbreak.
56
What should you do for a pregnant woman with suspected smallpox who has a history of recent exposure to a confirmed case?
Pregnant women should be vaccinated with a replication-competent vaccine unless antivirals are available.
57
What should you do for a breastfeeding woman with suspected smallpox who has a history of recent exposure to a confirmed case?
Breastfeeding women should be vaccinated with a replication-competent vaccine unless antivirals are available.
58
What should you do for a patient with suspected smallpox who has a history of recent exposure to a confirmed case and has atopic dermatitis?
Vaccination with replication-competent vaccine is relatively contraindicated. Instead, vaccinate with Immune if available.
59
What should you do for a patient with suspected smallpox who has a history of recent exposure to a confirmed case and has HIV with a CD4 count of 150 cells/L?
Vaccination with replication-competent vaccine is relatively contraindicated. Instead, vaccinate with Immune if available.
60
What is the overall mortality rate for variola major and variola minor?
**Variola major**: 30%
**Variola minor**: <1%
61
What are the indications for postexposure vaccination against smallpox?
**Within 2-3 days of exposure**: Provides protection against severe disease.
**Within 4-5 days of exposure**: May protect against death.
62
What antiviral medication is specific for smallpox?
The specific antiviral medication for smallpox is not provided in the text.
63
What antiviral medication is specific for Orthopoxvirus and how does it work?
**Tecovirimat**:
- Used under Emergency Use Authorization during a smallpox outbreak.
- Targets the F13L vaccinia gene.
- Prevents viral egress from infected cells and reduces morbidity and mortality of variola infection in nonhuman primates.
64
What are the recommendations for vaccination in individuals with known exposure to smallpox?
Individuals with known exposure should be vaccinated with **replication-competent smallpox vaccine** unless they are severely immunodeficient and not expected to benefit from the vaccine.
65
What is the effectiveness of vaccination with vaccinia virus in preventing smallpox disease?
Vaccination with vaccinia virus is **90-96% effective** in preventing smallpox disease when given before exposure to the variola virus.
66
What are the potential adverse effects of vaccination with vaccinia virus?
- Risk of outbreak is generally low.
- Risk of adverse effects is significant, which is why vaccination is not currently available to the general public.
67
What is the significance of revaccination for smallpox?
- Revaccination may provide significant protection for at least **30 years** after the initial vaccination, which typically offers full protection for **3 to 5 years** with waning immunity thereafter.
68
What is the overall mortality rate for variola major and variola minor?
- Variola major: 30%
- Variola minor: <1%
69
What are the indications for postexposure vaccination against smallpox?
- Within 2-3 days of exposure: protection against severe disease.
- Within 4-5 days of exposure: may protect against death.
70
What is exposure in the context of smallpox?
Exposure may protect against death.
71
What antiviral medication is specific for Orthopoxvirus and how does it work?
Tecovirimat is an Orthopoxvirus-specific antiviral medication that targets the F13L vaccinia gene, preventing viral egress from infected cells and reducing morbidity and mortality of variola infection in nonhuman primates.
72
What is the risk associated with vaccination with vaccinia virus for the general public?
The risk of outbreak is generally low.
## Footnote
The risk of adverse effects is significant.
73
What is the recommended management for a patient suspected of having smallpox?
Isolate the patient in a negative-pressure room.
## Footnote
Administer postexposure vaccination before the development of symptoms to reduce occurrence and severity.
74
What are the characteristics of hemorrhagic smallpox?
Hemorrhagic smallpox has a mortality rate of nearly 100%.
75
What should be done for individuals with known exposure to smallpox during an outbreak?
They should be vaccinated with replication-competent smallpox vaccine unless they are severely immunodeficient and not expected to benefit from the vaccine.
76
What is the significance of revaccination for smallpox?
Revaccination may provide significant protection for at least 30 years, as primary vaccination gives full protection for 3 to 5 years with waning immunity thereafter.
77
What are the potential treatments being studied for smallpox?
Tecovirimat and Brincidofovir are being studied; Tecovirimat targets the F13L gene, while Brincidofovir is a lipid conjugate of cidofovir with broad-spectrum activity against double-stranded DNA viruses.
78
What is the mortality rate for modified smallpox?
The mortality rate for modified smallpox is not provided in the text.
79
What is the mortality rate for modified smallpox?
The mortality rate for modified smallpox is <10%.
80
What is the role of the U.S. government in the event of a smallpox outbreak?
The U.S. government has stockpiled enough smallpox vaccine to vaccinate the entire U.S. population.
81
What are the contraindications for vaccination with replication-competent vaccine?
It is relatively contraindicated for individuals with atopic dermatitis and those with HIV infection with CD4 counts 50 to 199 cells/mm³.
82
What is the expected outcome for those who survive smallpox?
Those who survive smallpox will have lifetime immunity.
83
What is the effectiveness of vaccination with vaccinia virus in preventing smallpox disease?
Vaccination with vaccinia virus is 90-96% effective in preventing smallpox disease when given before exposure to variola virus.
84
What is the importance of isolation for smallpox patients?
Isolation in a negative-pressure room is crucial to prevent the spread of the virus to others.
85
What are the clinical features that can be confused with smallpox?
Disseminated herpes zoster, coxsackievirus, measles, human monkeypox, secondary syphilis, and various hemorrhagic fevers can resemble smallpox.
86
What is the role of post-exposure vaccination in smallpox management?
Post-exposure vaccination can reduce the occurrence and severity of smallpox if administered before the development of symptoms.
87
What is the mortality rate for flat smallpox?
The mortality rate for flat smallpox is >90%.
88
What should be done for pregnant and breastfeeding women in the context of smallpox vaccination?
They should be vaccinated with replication-competent vaccine if there is a risk of exposure.
89
What is the expected mortality for ordinary smallpox based on lesion presentation?
The mortality for ordinary smallpox ranges from less than 10% when lesions are discrete to 50-75% when lesions are confluent.
90
What is the significance of the F13L gene in smallpox treatment?
Targeting the F13L gene with Tecovirimat prevents viral egress from infected cells, reducing morbidity and mortality.
91
What is the expected duration of immunity after primary smallpox vaccination?
Primary vaccination provides full protection for 3 to 5 years, with waning immunity for at least another 10 years.
92
What is the role of the National Institutes of Health in smallpox treatment development?
They aim to identify broad-spectrum antivirals that have obtained FDA approval for other viral indications for use against orthopoxviruses.
93
What is the clinical significance of secondary syphilis lesions in relation to smallpox?
Secondary syphilis lesions can appear on palms and soles but do not progress, differentiating them from smallpox lesions.
94
What is the importance of vaccination for lab workers handling orthopoxviruses?
Vaccination is indicated for lab workers handling non-highly attenuated orthopoxviruses to protect against suspected smallpox outbreaks.
95
What are the implications of using Imvamune during a smallpox outbreak?
Imvamune is a replication-deficient strain that may be used under investigational mechanisms for individuals who cannot receive replication-competent vaccines.
96
What is the expected outcome for individuals with hemorrhagic smallpox?
The expected outcome is nearly 100% mortality for individuals with hemorrhagic smallpox.
97
What is the significance of the ACAM2000 vaccine in smallpox prevention?
ACAM2000 contains replication-competent virus and is used for postexposure protection in smallpox outbreaks.
98
What is the clinical course of smallpox in terms of death occurrence?
Death typically occurs during the 2nd week of illness, often due to toxemia leading to hypotension, shock, and multiorgan failure.
99
What is the role of Brincidofovir in smallpox treatment?
Brincidofovir is being studied as a potential smallpox therapy, showing promising results in reducing mortality in initial studies.
100
What is the expected mortality for flat smallpox?
The mortality rate for flat smallpox is >90%.
101
What is the significance of vaccination timing in relation to smallpox exposure?
Vaccination within 2-3 days of exposure provides protection against severe disease, while vaccination within 4-5 days may protect against death.
102
What is the expected outcome for individuals who survive smallpox?
Those who survive smallpox will have lifetime immunity.
103
What is the likely cause for a patient with a history of recent vaccination presenting with conjunctivitis and keratitis?
The patient likely has accidental vaccinia due to autoinoculation of the vaccinia virus from the vaccination site to the eye.
104
What are the indications for vaccination against smallpox using vaccinia virus?
Preexposure prevention of smallpox for laboratory workers, first responders, and some military personnel.
## Footnote
- Postexposure prophylaxis against severe disease and death.
105
What are the common local skin reactions following smallpox vaccination?
Normal local skin reaction begins 3-5 days after administration.
## Footnote
Progression: Papule → vesicle (Jennerian vesicle) → pustule (days 7-9) → crusts and scabs (days 10-14) → scab detaching (days 17-21) leaving residual scar.
106
What is a robust local cutaneous reaction?
Robust local cutaneous reaction (≥7.5 cm) occurs in up to 16% of vaccinations, peaking 6-12 days after vaccination and improving spontaneously in 24-72 hours.
107
What are the noncutaneous findings associated with smallpox vaccination?
Soreness at the vaccination site (almost universally occurs).
## Footnote
Lymphadenopathy/lymphangitis.
108
What systemic symptoms are considered normal reactions to smallpox vaccination?
Fever (>37.7°C [99.9°F], more common in children), chills, headache, myalgias, malaise.
## Footnote
Peak at days 8-10, lasting 1-3 days.
109
What percentage of individuals feel too ill to carry out normal activities after vaccination?
Approximately 30% feel too ill to carry out normal activities.
110
What are the potential cutaneous complications from vaccination?
Adverse effects from vaccination were studied most extensively for the first-generation vaccine (Dryvax).
## Footnote
Second-generation vaccines (ACAM2000, APSV, Imvambune) are less well-studied.
111
What are the characteristics of adverse cutaneous reactions?
Adverse cutaneous reactions can be localized or generalized and are 10x more common in primary vaccination vs. revaccination.
112
What secondary infections can occur at the primary site after vaccination?
Secondary bacterial infections (e.g., Staph or Group A strep) can occur at the primary site.
113
What is accidental vaccinia and what are its common adverse events?
Accidental vaccinia refers to autoinoculation of vaccinia virus from the vaccination site to another area.
## Footnote
Most common adverse event seen (1/2 of all adverse events).
114
What are common sites for accidental vaccinia?
Common sites include eyelids, nose, mouth.
115
What are common sites for cutaneous reactions following vaccination?
Common sites include eyelids, nose, mouth, and genitalia.
116
When are cutaneous reactions usually seen after vaccination?
Usually seen 7-10 days after vaccination, following the time course of the original primary lesion.
117
What are the indications for vaccination against smallpox using vaccinia virus?
Indications include:
- Preexposure prevention for laboratory workers, first responders, and some military personnel.
- Postexposure prophylaxis against severe disease and death.
118
What are the contraindications for vaccination in the preexposure setting?
Contraindications include:
- History of atopic dermatitis or disruption of the skin barrier.
- Immunosuppression in self or close contact.
- Heart disease or significant cardiac risk factors.
- Serious allergy to vaccine components.
- Age younger than 12 months.
- Pregnancy, breastfeeding, or pregnant close contact.
119
What are the typical cutaneous findings following vaccination with vaccinia virus?
Typical cutaneous findings include:
- Normal local skin reaction begins 3-5 days after administration.
- Progression from papule to vesicle to pustule, followed by crusts and scabs.
- Robust local cutaneous reaction occurs in up to 16% of vaccinations, which can be mistaken for bacterial cellulitis.
- Secondary bacterial infections may occur within the first 5 days or 30 days after vaccination.
120
What systemic symptoms are considered normal reactions to vaccination?
Systemic symptoms include:
- Fever (>37.7C [99.9F], more common in children).
- Chills, headache, myalgias, malaise.
- Symptoms typically peak at days 8-10 and last for 1-3 days.
121
What are the potential cutaneous complications associated with vaccination?
Potential cutaneous complications may include secondary bacterial infections and robust local reactions.
122
What are potential cutaneous complications associated with vaccination?
Potential cutaneous complications include:
- Adverse effects such as localized or generalized reactions.
- Secondary bacterial infections (e.g., Staph or Group A strep).
- Accidental vaccinia leading to autoinoculation of the virus to another area, commonly affecting eyelids, nose, mouth, and genitalia.
123
How does the risk of adverse reactions differ between primary vaccination and revaccination with vaccinia virus?
Adverse reactions are 10 times more common in primary vaccination compared to revaccination.
124
What is the expected timeline for local skin reactions following vaccinia vaccination?
The expected timeline is as follows:
1. Normal local skin reaction begins 3-5 days after administration.
2. Papule forms and progresses to vesicle (days 7-9).
3. Vesicle becomes pustule (days 7-9).
4. Crusts and scabs form (days 10-14).
5. Scab detachment occurs (days 17-21), leaving a residual scar.
125
What are the common adverse effects associated with the first-generation smallpox vaccine, Dryvax?
Common adverse effects include:
- Localized skin reactions.
- Secondary bacterial infections.
- Systemic symptoms such as fever and malaise.
- Risk of more severe adverse effects in immunocompromised individuals.
126
What is the significance of a robust local cutaneous reaction following vaccinia vaccination?
A robust local cutaneous reaction (≥7.5 cm) indicates that the vaccination has been effective, as it occurs in up to 16% of vaccinations and can be mistaken for bacterial cellulitis.
127
What are the implications of accidental vaccinia, and what are the common sites affected?
Accidental vaccinia refers to autoinoculation of the virus to another area, commonly affecting sites such as eyelids, nose, mouth, and genitalia.
128
What does accidental vaccination refer to?
Accidental vaccination refers to autoinoculation of the vaccinia virus from the vaccination site to another area.
129
What are common sites affected by accidental vaccination?
Common sites affected include:
- Eyelids
- Nose
- Mouth
- Genitalia
130
How common is accidental vaccination as an adverse event?
This is the most common adverse event seen, occurring usually 7-10 days after vaccination.
131
What are the characteristics of the Imvamune vaccine compared to replication-component vaccines?
Imvamune is a highly attenuated vaccine that:
- Is incapable of replicating in human cells.
- Produces no skin reaction and has no risk of secondary transmission.
132
What are the clinical features of generalized vaccinia following vaccination?
Generalized vaccinia can present as:
- Macular, popular, or vesicular lesions.
- Occurs without evidence of autoinoculation.
- May be associated with generalized, nonspecific immune-mediated reactions such as morbilliform and roseola-like rashes.
133
What is the expected duration of systemic symptoms following vaccination?
Systemic symptoms typically peak at days 8-10 and last for 1-3 days, with about 30% of individuals feeling too ill to carry out normal activities during this time.
134
What are the contraindications for vaccination in the postexposure setting?
In the postexposure setting, there are no absolute contraindications to vaccination, but caution is advised in immunocompromised individuals and those with certain skin conditions.
135
What is the relationship between vaccinia virus and other orthopoxviruses?
Vaccinia virus is closely related to other orthopoxviruses, such as monkeypox and cowpox, providing protection against these viruses as well as smallpox.
136
What are the common local reactions that can occur near the vaccination site?
Common local reactions include:
- Intense surrounding erythema and swelling.
137
What are common local reactions to vaccination?
Common local reactions include:
- Intense surrounding erythema.
- Edema.
- Satellite lesions.
138
What is the significance of the vaccination history in the context of smallpox vaccination?
Vaccination against smallpox was discontinued in the US in 1972 and globally after 1980, but was reinitiated in 2002 for military and health care workers, indicating a need for preparedness in case of outbreaks.
139
What are the expected cutaneous findings in infants and children under 5 years following vaccination?
Adverse cutaneous reactions are more common in infants and children under 5 years, with reactions being localized or generalized and potentially leading to secondary infections.
140
What is the timeline for the development of a robust local cutaneous reaction after vaccination?
A robust local cutaneous reaction typically peaks 6-12 days after vaccination and improves spontaneously within 24-72 hours.
141
What are the common systemic reactions observed in children following vaccination?
Common systemic reactions in children include:
- Fever (>37.7C [99.9F]).
- Chills.
- Headache.
- Myalgias.
- Malaise, which may lead to significant discomfort.
142
What is the expected progression of skin lesions following vaccination?
The expected progression of skin lesions is as follows:
1. Papule forms (days 7-9).
2. Vesicle develops (Jennerian vesicle).
3. Pustule formation occurs (days 7-9).
4. Crusts and scabs form (days 10-14).
5. Scab detachment occurs (days 17-21).
143
What are the potential risks associated with vaccination in individuals with atopic dermatitis?
Individuals with atopic dermatitis carry a risk of more severe adverse reactions.
144
What risk is associated with vaccination in individuals with atopic dermatitis?
Individuals with atopic dermatitis carry a risk of more severe adverse effects from vaccination, necessitating careful consideration before vaccination.
145
What is the role of vaccinia virus in the context of smallpox vaccination?
Vaccinia virus serves as the primary vaccine used to confer immunity against smallpox, as it is a member of the Orthopoxvirus genus and provides cross-protection against related viruses.
146
What are the clinical implications of the timeline for local skin reactions following vaccination?
Understanding the timeline for local skin reactions helps healthcare providers anticipate and manage potential adverse effects, ensuring timely intervention if complications arise.
147
What are the characteristics of the second-generation vaccines ACAM2000 and APSV?
ACAM2000 and APSV are second-generation vaccines that:
- Are derived from the same viral strain as Dryvax.
- Have a safety profile expected to be similar to Dryvax.
- Are less well-studied compared to first-generation vaccines.
148
What is the significance of vaccination history for healthcare workers in the context of smallpox outbreaks?
Healthcare workers' vaccination history is crucial for preparedness in case of smallpox outbreaks, as they are often the first responders and may be at higher risk of exposure.
149
What are the expected outcomes for individuals who experience robust local cutaneous reactions after vaccination?
Individuals with robust local cutaneous reactions can expect:
- Symptoms to improve spontaneously within 24-72 hours.
- Monitoring for potential secondary infections due to the size of the reaction.
150
What is the diagnosis for a patient with eczema who develops widespread lesions after contact with a recently vaccinated individual?
The diagnosis is eczema vaccinatum, which can occur in individuals with atopic dermatitis after secondary transmission of vaccinia virus.
151
What is generalized vaccinia and how does it manifest in immunocompromised individuals?
Generalized vaccinia can be limited or extensive and can occur anywhere on the body. It is thought to be caused by the spread of the virus via the bloodstream, occurring 6-9 days after primary vaccination. In immunocompetent individuals, it is self-limited, but it can be more severe in immunosuppressed individuals.
152
What are the symptoms and complications associated with eczema vaccinatum?
Eczema vaccinatum is characterized by localized or generalized spread of the vaccinia virus in individuals with atopic dermatitis or other chronic dermatoses. Symptoms include fever, malaise, and lymphadenopathy. Lesions can occur anywhere on the body, often in areas with prior lesions of atopic dermatitis, and can range from several to hundreds. Serious cases can result in substantial loss of skin barrier.
153
What are the potential CNS complications following smallpox vaccination?
CNS complications can include postvaccinal encephalopathy, which presents with symptoms like fever, headache, seizures, and can lead to confusion and coma. Other complications include postvaccinal encephalitis and myelitis, which can occur 11-15 days after vaccination and may result in severe neurological deficits.
154
What is the mortality rate associated with eczema vaccinatum and progressive vaccinia?
The mortality rate for eczema vaccinatum is approximately.
155
What is the mortality rate for eczema vaccinatum?
The mortality rate for eczema vaccinatum is approximately 30-40%.
156
What is the outcome of untreated progressive vaccinia?
Progressive vaccinia is universally fatal if untreated.
157
What are the CNS complications associated with eczema vaccinatum?
CNS complications have a mortality rate of 15-25%, with survivors potentially experiencing residual sequelae such as mental impairment and paralysis.
158
What management strategies are recommended for generalized vaccinia?
Management of generalized vaccinia typically requires only symptomatic treatment.
159
What additional treatment may be beneficial for severe cases of generalized vaccinia?
In severe cases, especially in immunocompromised individuals, intravenous vaccinia immune globulin (VIG) may be beneficial.
160
How should secondary bacterial infections be treated in generalized vaccinia?
Secondary bacterial infections should be treated with appropriate antimicrobial therapy.
161
What are the potential complications of generalized vaccinia in immunosuppressed individuals?
Generalized vaccinia can lead to severe complications such as:
- **Hypersensitivity reactions**: erythema multiforme, Stevens-Johnson syndrome (SJS)
- **Eczema vaccinatum**: localized or generalized spread of vaccinia virus, presenting with fever, malaise, and lymphadenopathy, often occurring at the same time as lesions at the vaccination site.
- **Progressive vaccinia**: characterized by non-healing lesions that progress to painless ulcers with central necrosis, and can lead to viremia and metastatic lesions in distant sites.
162
How does eczema vaccinatum present in individuals with atopic dermatitis?
Eczema vaccinatum presents as:
- Localized or generalized spread of vaccinia virus in individuals with atopic dermatitis (AD).
- Symptoms include fever, malaise, and lymphadenopathy.
- Lesions can occur anywhere on the body, particularly in areas with prior AD lesions.
163
What is the clinical significance of postvaccinal encephalopathy and its symptoms?
Postvaccinal encephalopathy is a serious complication that can occur in children under 2 years old, characterized by:
- Abrupt onset of symptoms 6-10 days after vaccination, including fever, headache, seizures, hemiplegia, aphasia, and transient amnesia.
- It is associated with cerebral edema without inflammation and can lead to long-term neurological deficits.
164
What are the management strategies for secondary bacterial infections following smallpox vaccination?
Management strategies for secondary bacterial infections following smallpox vaccination include:
- **Appropriate antimicrobial therapy** to treat the infection.
- **Symptomatic treatment** for minor local events and typical systemic symptoms.
- Monitoring for complications and providing supportive care as needed.
165
What is the expected clinical course following smallpox vaccination, and what are the key stages?
The expected clinical course following smallpox vaccination includes:
1. **Papule** at the inoculation site (several days after administration).
2. Progression to **vesicle**.
3. Development of **pustule**.
4. Formation of **scabs** (within 2 weeks).
5. Scabs fall off (within 3 weeks) and leave a scar.
## Footnote
This progression indicates an effective immune response to the vaccination.
166
What are the potential outcomes of progressive vaccinia if left untreated?
If progressive vaccinia is left untreated, it can lead to severe complications, including extensive tissue damage and systemic infection.
167
What are the potential outcomes if progressive vaccinia is left untreated?
1. Universally fatal if untreated.
2. Development of extensive lesions that do not heal, leading to severe systemic complications.
3. Risk of viremia and metastatic lesions affecting distant sites in the body, including skin, bone, and viscera.
168
What role do IgM antibodies play in the immune response following smallpox vaccination?
IgM antibodies play a crucial role in the immune response following smallpox vaccination by:
1. Being detectable as early as day 4 post-vaccination.
2. Potentially preventing the spread of the virus, thereby reducing the risk of severe complications.
3. Indicating an early immune response to the vaccination.
169
What are the implications of vaccinating during pregnancy regarding fetal health?
Vaccination during pregnancy can have serious implications for fetal health, including:
1. Rarely leading to fetal or congenital vaccinia.
2. Transmission to the fetus can occur at any time during pregnancy, resulting in lesions on the skin, mucous membranes, and placenta.
3. The appearance of lesions can be similar to generalized or progressive vaccinia, which can be extensive and life-threatening.
170
What are the common adverse events associated with smallpox vaccination?
Common adverse events associated with smallpox vaccination include:
1. **Eczema vaccinatum**: 30-40% mortality rate if untreated.
2. **Progressive vaccinia**: universally fatal if untreated.
3. **CNS complications**: 15-25% may recover in approximately 2 weeks, but 25% of survivors may have residual sequelae such as mental impairment or paralysis.
171
What are potential complications from smallpox vaccination?
Complications can include mental impairment or paralysis.
172
How is the diagnosis of complications from smallpox vaccination typically made?
The diagnosis is typically made through:
- A **recent history of vaccination**.
- A history of recent vaccination of a close contact, which may suggest **secondary transmission** of the virus.
173
What should be done if a pregnant woman is inadvertently vaccinated with a replication-competent smallpox vaccine?
Vaccination during pregnancy is not ordinarily a reason for termination. However, VIG might be considered for a viable infant born with vaccination lesions.
174
What should you do for a patient with suspected smallpox who has a history of recent exposure to a confirmed case and has cardiac disease?
The CDC advises against vaccination of individuals with known cardiac disease.
175
What should you do for a patient with suspected smallpox who is under 18 years old?
Prevent vaccination of individuals under 18 is not recommended, and vaccination of children under 1 year old is contraindicated.
176
What should you do for a patient with suspected smallpox who is under 1 year old?
Vaccination of children under 1 year old is contraindicated.
177
What should you do for a patient with suspected smallpox who is allergic to the vaccine components?
Vaccination is contraindicated for individuals allergic to any component of the vaccine.
178
What should you do if a suspected smallpox patient has a history of recent exposure to a confirmed case and has a disrupted skin barrier?
Vaccination is contraindicated for individuals with a disrupted skin barrier.
179
What should you do if a suspected smallpox patient has a history of recent exposure to a confirmed case and has household contact with atopic dermatitis?
Vaccination is contraindicated for individuals with household contacts who have atopic dermatitis.
180
What should you do if a suspected smallpox patient has a history of recent exposure to a confirmed case and has household contact who is immunosuppressed?
Vaccination is contraindicated for individuals with household contacts who are immunosuppressed.
181
What should you do if a suspected smallpox patient has a history of recent exposure to a confirmed case and has household contact who is pregnant?
Vaccination is contraindicated for individuals with household contacts who are pregnant.
182
What should you do if a suspected smallpox patient has a history of recent exposure to a confirmed case and has household contact who is breastfeeding?
Vaccination is contraindicated for individuals with household contacts who are breastfeeding.
183
What should you do if a suspected smallpox patient has a history of recent exposure to a confirmed case and has household contact who is under 1 year old?
Vaccination is contraindicated for individuals with household contacts who are under 1 year old.
184
What should you do if a suspected smallpox patient has a history of recent exposure to a confirmed case and has household contact who is under 18 years old?
Vaccination is contraindicated for individuals with household contacts who are under 18 years old.
185
What should you do if a household contact is under 18 years old?
Prevent vaccination of individuals under 18 is not recommended.
186
What should you do if a patient with suspected smallpox has a household contact with cardiac disease?
The CDC advises against vaccination of individuals with household contacts who have cardiac disease.
187
What should you do if a patient with suspected smallpox has a household contact with a disrupted skin barrier?
Vaccination is contraindicated for individuals with household contacts who have a disrupted skin barrier.
188
What should you do if a patient with suspected smallpox has a household contact who is allergic to the vaccine components?
Vaccination is contraindicated for individuals with household contacts who are allergic to the vaccine components.
189
What should you do if a patient with suspected smallpox has a household contact who is immunosuppressed?
Vaccination is contraindicated for individuals with household contacts who are immunosuppressed.
190
What should you do if a patient with suspected smallpox has a household contact who is pregnant?
Vaccination is contraindicated for individuals with household contacts who are pregnant.
191
What should you do if a patient with suspected smallpox has a household contact who is breastfeeding?
Vaccination is contraindicated for individuals with household contacts who are breastfeeding.
192
Who is breastfeeding?
Vaccination is contraindicated for individuals with household contacts who are breastfeeding.
193
What is the role of VIG in the treatment of eczema vaccinum?
Early treatment with VIG has been shown to reduce mortality from 30-40% down to 7%. VIG administration in an ICU setting reduces the case fatality rate of progressive vaccinia from 100% to 20-30%.
194
What precautions should be taken to prevent inadvertent transmission of the live virus from the vaccination site?
The vaccination site should be covered with gauze and an overlying semipermeable membrane bandage until scabs have shed. Contact precautions and frequent hand washing are also important when caring for the vaccination site.
195
Who should not receive the smallpox vaccination?
Vaccination is contraindicated for individuals with a history of atopic dermatitis, those with a currently disrupted skin barrier, immunosuppressed individuals, those allergic to any component of the vaccine, pregnant or breastfeeding women, and individuals with known cardiac disease. Vaccination is also not recommended for individuals under 18 years old, and it is contraindicated for children under 1 year old.
196
What is the clinical significance of inadvertent vaccination during pregnancy?
Inadvertent vaccination during pregnancy is not ordinarily a reason for termination. There is no indication for VIG administration to a pregnant woman, but it might be considered for a viable infant born with vaccinia lesions.
197
What is the recommended care for patients with eczema vaccinum?
Meticulous skin care and fluid and electrolyte replenishment are needed.
198
What is the effect of VIG administration in an ICU setting for progressive vaccinia?
VIG administration and care in an ICU setting reduces the case fatality rate of progressive vaccinia from 100% to 20-30%.
199
What are the indications for VIG administration in pregnant women?
There is no indication for VIG administration to pregnant women, but it might be considered for a viable infant born with vaccinia lesions.
200
What precautions should be taken to prevent inadvertent transmission of the live virus from the vaccination site?
The vaccination site should be covered with gauze and an overlying semi-permeable membrane bandage until scabs have shed. Contact precautions and frequent hand washing are also important.
201
Who should not receive preemptive vaccination against smallpox?
Preemptive vaccination is contraindicated for individuals with a history of atopic dermatitis, currently disrupted skin barrier, immunosuppressed individuals, those allergic to any component of the vaccine, and pregnant or breastfeeding individuals.
202
What is the recommendation regarding vaccination for individuals under 18 years old?
Vaccination is not recommended for individuals under 18 years old, and vaccination of children under 1 year old is contraindicated.
203
What is the CDC's stance on vaccinating individuals with known cardiac disease?
The CDC is against vaccination of individuals with known cardiac disease.
204
What supportive care is recommended for neurologic complications associated with smallpox vaccination?
Supportive care is recommended, but there is no evidence that VIG is effective in treating neurologic complications.
205
What is the effect of early treatment with VIG on mortality rates?
Early treatment with VIG has been shown to reduce mortality from 30-40% down to 7%.
206
Is VIG effective in cases of inadvertent vaccination during pregnancy?
There is no evidence that VIG is effective in these cases.
207
What should be done if inadvertent vaccination occurs during pregnancy?
Inadvertent vaccination during pregnancy is not ordinarily a reason for termination.
208
What is the role of VIG in the treatment of eczema vaccinatum?
VIG has been shown to reduce mortality in eczema vaccinatum, particularly when administered early, but its effectiveness in neurologic complications is not supported by evidence.
209
What are the main clinical features of Variola virus infection in humans?
High fever and malaise precede oropharyngeal erythema and centrifugal exanthem. Simultaneous progression of skin lesions from macules to papules, pustules, and crusts results in significant scars.
210
What is the treatment approach for Vaccinia virus infection?
Symptomatic treatment for minor local reactions. Vaccination with immune globulin or cidofovir for severe cases. Postexposure vaccination to reduce severity and disease occurrence prior to onset of clinical symptoms.
211
How does the clinical presentation of Monkeypox virus compare to that of Smallpox?
Clinical presentation is similar to that of smallpox but with more prominent lymphadenopathy and lower mortality.
212
What is the main portal of entry for Cowpox virus in humans?
The main portal of entry for Cowpox virus is through the skin, typically via contact with infected animals.
213
What are the clinical features associated with Molluscum contagiosum virus infection?
Discrete firm, dome-shaped papules; may be external in individuals with competent or immune-compromised systems. Most lesions resolve spontaneously.
214
What are the characteristics of lesions in immunocompromised individuals?
Most lesions resolve spontaneously in months to years, but can be treated to reduce symptoms and minimize potential for infection.
215
What is the treatment for Yatapox virus infection?
Self-resolving within 6 weeks, resulting in immunity. In severe cases, treatment may include debridement and supportive care.
216
What are the main clinical features associated with Variola virus infection in humans?
High fever and malaise precede oropharyngeal erythema and centrifugal rash. Progression of skin lesions from macules to papules, pustules, and crusts results in significant scars.
217
What is the treatment approach for Vaccinia virus infection?
Used as a vaccine for smallpox. Adverse events occur when virus spreads locally in immunocompromised individuals, leading to severe skin lesions.
218
What are the main clinical features of Cowpox virus infection?
Infection can lead to papules that become vesicular, hemorrhagic, pustular, and ulcerative, resolving over several weeks. Constitutional symptoms and lymphadenopathy are common.
219
What is the main portal of entry for Orf virus in humans?
The main portal of entry for Orf virus is through the skin, typically from contact with infected animals.
220
What is the treatment for Yatapox virus infection?
Treatment is supportive; self-resolving within 6 weeks, with resulting immunity.
221
What are the clinical features of Molluscum contagiosum virus infection?
Discrete firm, dome-shaped papules that may become centrally umbilicated. Can be extensive in individuals with atopic dermatitis or immune compromise.
222
What is the significance of the healing process in Cowpox virus infection?
Healing occurs over 4-6 weeks, usually without scarring, but can be extensive in immunocompromised individuals.
223
What is the primary mode of transmission for Pseudocowpox virus?
Transmission occurs by contact with infected teats or milking equipment, similar to Cowpox virus.
224
What are the common symptoms associated with Orf virus infection?
Symptoms include painful papules that can become vesicular and may lead to ulceration, typically resolving without significant complications.
225
What is the recommended treatment for severe cases of Vaccinia virus infection?
Vaccinia immune globulin is recommended for severe cases, especially in immunocompromised individuals.
226
How does the clinical course of Yatapox virus infection differ from other poxviruses?
Yatapox virus infection is self-limiting, resolving within 6 weeks, and typically does not require specific treatment.
227
What is the main portal of entry for the Variola virus?
The main portal of entry for Variola virus is the respiratory tract.
228
What are the potential complications of Monkeypox virus infection?
Potential complications include severe skin lesions and secondary bacterial infections due to skin integrity loss.
229
What is the significance of lymphadenopathy in Monkeypox virus infection?
Lymphadenopathy is a notable feature of Monkeypox virus infection, indicating systemic involvement.
230
What is the significance of lymphadenopathy in Monkeypox virus infection?
Lymphadenopathy is more prominent in Monkeypox compared to Smallpox, indicating a different immune response.
231
What are the clinical features of Bovine papular stomatitis virus infection?
Clinical findings are similar to those of Cowpox virus, with lesions on the mouth and muzzle of cattle.
232
What is the treatment for Orf virus infection?
Treatment is generally supportive, with resolution expected within 4-6 weeks.
233
What is the primary host for the Pseudocowpox virus?
The primary host for Pseudocowpox virus is cattle, particularly during milking.
234
What are the common clinical features of Yatapox virus infection?
Yatapox virus infection can cause lesions that resemble those of other poxviruses, with potential for ulceration.
235
What is the significance of the immune response in individuals infected with Molluscum contagiosum virus?
Individuals with compromised immune systems may experience more extensive lesions and prolonged infection.
236
What is the treatment for Cowpox virus infection?
There is no known treatment; management is supportive, focusing on symptom relief.
237
What is the main clinical concern regarding the use of Vaccinia virus as a vaccine?
Adverse events can occur, particularly in immunocompromised individuals, leading to severe local reactions.
238
What is the typical presentation of lesions caused by the Orf virus?
Lesions typically present as painful papules that can progress to vesicular and ulcerative stages.
239
What is the role of supportive care in the management of Yatapox virus infection?
Supportive care is crucial as the infection is self-limiting, focusing on symptom management.
240
What are the potential outcomes of untreated Cowpox virus infection?
Untreated Cowpox virus infection typically resolves without complications, but can lead to significant scarring in some cases.
241
What is the clinical significance of the rash progression in Variola virus infection?
The progression from macules to papules, pustules, and crusts is characteristic and helps in diagnosis.
242
What is the expected resolution time for lesions caused by Yatapox virus?
Lesions typically resolve within 6 weeks, leading to lasting immunity.
243
What is the primary mode of transmission for Molluscum contagiosum virus?
Transmission occurs through direct skin-to-skin contact, often in individuals with compromised immune systems.
244
What are the common symptoms associated with Cowpox virus infection?
Symptoms include fever, malaise, and the development of skin lesions that can become vesicular and ulcerative.
245
What is the significance of the central umbilication in Molluscum contagiosum lesions?
Central umbilication is a distinctive feature that helps differentiate Molluscum contagiosum from other skin lesions.
246
What is the treatment for severe cases of Orf virus infection?
Severe cases may require topical antiseptics and pain management, but most cases resolve spontaneously.
247
What is the clinical presentation of lesions caused by Pseudocowpox virus?
Lesions are similar to those of Cowpox virus, typically presenting as papules that can become vesicular.
248
What is the expected clinical course for individuals infected with the Yatapox virus?
The clinical course is generally mild, with self-limiting lesions that resolve without significant complications.
249
What are self-limiting lesions?
Lesions that resolve without significant intervention.
250
What is the typical healing time for lesions caused by Cowpox virus?
Lesions typically heal over 4-6 weeks, often without scarring, but can be extensive in immunocompromised individuals.
