Virus
Monkeypox
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Monkeypox
, Monkey Pox, Monkeypox Virus, Human Monkeypox, Monkeypox Virus Infection
Pathophysiology
Virus
in the
Orthopoxvirus
genus (same genus as
Smallpox
and
Cowpox
)
Viral Infection
whose natural hosts are primates and rodents
Primarily in the tropical forests of West and Central Africa (esp. Congo Basin)
Transmission to humans from animals is typically via bites or contact with the animal's blood
Human to human transmission (much less common than with
Smallpox
)
Respiratory transmission (primary route)
Contact with infectious skin lesions
Outbreaks
Originally limited to Democratic Republic of Congo (and
Refugee
s and
Immigrant
s from that region)
Cases seen primarily in Africa (e.g. Cameroon, Liberia, Nigeria, Sierra Leone) with rare reported cases in Europe
Isolated outbreak occurred in U.S. in 2003, related to rodents imported from West Africa
In 2022, cases have been seen globally including the United States
Course
Incubation Period
: 5 to 17 days
Duration: 2 to 4 weeks
Types
Strains
West African Monkeypox
Milder illness with fewer deaths than with Central African Monkeypox
Limited human-to-human transmission
Central African Monkeypox Virus
More severe cases with higher mortality
Higher risk of person-to-person spread
Risk Factors
Recent travel to endemic regions (esp. central and west african countries)
Men who have Sex with Men
Findings
Febrile Prodrome
Fever
Chills
Malaise
Headache
Marked
Lymphadenopathy
(generalized or localized)
Rash
Characteristics
Vesiculopustular rash
Deep seated, firm, well-circumscribed lesions
Lesions are of similar size to one another and are typically in same stage in a particular body region
Lesions are painful until they crust or scab and begin to heal, at which time they are pruritic
Distribution:
Gene
ralizes over first 24 hours as Centrifugal Rash (trunk is more spared)
First:
Tongue
and mouth often show initial lesions
Next: Face is often involved
Next: Extremities (esp. Palms and soles)
May also be found in perianal and genital regions (sexually transmitted)
Lesions progress over a 2 to 4 week period
Macule
(1 to 2 days)
Papule
(1 to 2 days)
Vesicle
s with clear fluid (1 to 2 days)
Pustule
with opaque fluid and
Central DI
mple or umbilication (5 to 7 days)
Crust
or scab (7 to 14 days)
Variations
Lesion may coalesce into larger scabs
Labs
Orthopoxvirus
DNA PCR
Preferred primary test in U.S.
Orthopoxvirus
Immunochemical stain
Anti-
Orthopoxvirus
IgM
Positive from day 5 to day 56 after rash onset
Differential Diagnosis
Secondary Syphilis
Herpes Simplex Virus
Varicella Zoster Virus
Chancroid
Other Pox
Virus
es
Smallpox
Cowpox
Complications
Hemorrhagic disease
Sepsis
Encephalitis
Management
Supportive Care
Antivirals
Background
Indicated in patients with high risk of severe disease (see prognosis below)
These agents were primarily developed for use in
Smallpox
, and efficacy in Monkeypox is unclear
Agents
Tecovirimat (TPOXX, ST-246)
Vaccinia
Immune Globulin Intravenous (VIGIV)
Cidofovir (Vistide, primary indication is for
CMV Retinitis
)
Brincidofovir (CMX001, Tembexa)
Prognosis
High Risk Patients for Severe Disease
Immunocompromised
State
Human Immunodeficiency Virus
Infection (HIV or
AIDS
)
Gene
ralized Malignancy
Leukemia
Lymphoma
Solid Organ Transplant
ation
Immunosuppressants (e.g.
Alkylating Agent
s, antimetabolites,
Tumor Necrosis Factor Inhibitor
s, high-dose
Corticosteroid
s)
Status
Hematopoietic Stem Cell Transplant
(<24 months post-transplant or =24 months with graft-versus-host disease)
Other
Immunodeficiency
(e.g.
Autoimmune Condition
)
Other factors
Age <8 years old
Atopic Dermatitis
Active exfoliative skin conditions (e.g.
Eczema
, burns,
Impetigo
, VZV, HSV, severe acne, severe
Diaper Dermatitis
,
Psoriasis
)
Women in pregnancy or
Lactation
Disease complications
Secondary
Bacteria
l
Skin Infection
Gastroenteritis
with severe
Nausea
,
Vomiting
,
Diarrhea
or
Dehydration
Bronchopneumonia
Resources
McCollum (2020)
Smallpox
and Other
Orthopoxvirus
-Associated Infections, Yellow Book, Accessed 6/27/2022
https://wwwnc.cdc.gov/travel/yellowbook/2020/travel-related-infectious-diseases/smallpox-and-other-orthopoxvirus-associated-infections
Monkeypox Response (CDC), Accessed 6/27/2022
https://www.cdc.gov/poxvirus/monkeypox/response/2022/hcp/index.html
Monkeypox Clinical Recognition (CDC), Accessed 6/27/2022
https://www.cdc.gov/poxvirus/monkeypox/clinicians/clinical-recognition.html
Monkeypox Treatment (CDC), Accessed 6/27/2022
https://www.cdc.gov/poxvirus/monkeypox/clinicians/treatment.html
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