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MonkeyPox (Orthopoxvirus sp.)

BASICS

•Monkeypox is a rare disease caused by infection with monkeypox virus.

•Monkeypox virus belongs to the Orthopoxvirus genus in the family Poxviridae. The Orthopoxvirus genus also includes variola virus (which causes smallpox), vaccinia virus (used in the smallpox vaccine), and cowpox virus.

•There are two clades of monkeypox virus: the West African clade and the Congo Basin (Central African) clade.

DESCRIPTION

•Is a double-stranded DNA virus related to variola virus (the cause of smallpox), vaccinia virus, and cowpox virus.

•Discovered first in monkeys used for research in late 1950’s; first human case in the 1970’s in the Democratic Republic of Congo.

EPIDEMIOLOGY

•Predominately a disease found in Africa

•In the US in 2021, outbreak occurred in Texas related to imported pets

•Detected in a variety of animals, including man, rodents and monkeys

•As of 21 May, 13:00, 92 laboratory confirmed cases, and 28 suspected cases of Monkeypox with investigations ongoing, have been reported to WHO from 12 Member States. For non-endemic countries Portugal, Spain and the UK currently have the greatest documented cases.(https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON385)

ETIOLOGY AND PATHOPHYSIOLOGY

•Transmission can be through contact with infected bodily secretions (including saliva), via respiratory tract, skin injury, or fomites.

•Natural reservoir is unknown, however rodents and primates have been found to harbor the virus and infect humans.

•Animal to human transmission has occurred with animal bites, scratches, contact with infected secretions and skin lesions.

•Human to human transmission has been reported via respiratory and direct contact with infected secretions and skin lesions as well as sexual contact.

•Incubation is seen within 21 days of exposure.

RISK FACTORS

•Travel to Africa

•Physical or respiratory contact with contaminated exposures

GENERAL PREVENTION

•Smallpox vaccine may be effective at limiting severity of Monkeypox infection

•Limit exposure to those infected

•No travel to endemic regions (primarily Africa)

DIAGNOSIS

•HISTORY

•Almost 100% of patients have a prodrome of fever with chills, malaise and headaches.

•Travel to or exposure to someone who has traveled to an endemic region

•PHYSICAL EXAM

•Evolving rash begins within 1-3 days of fever onset, starting on the face and progressing to the rest of the body.

•Initially macules that become papular, then vesicular to pustules that eventually scab

•Rash can become painful as it evolves

DIFFERENTIAL DIAGNOSIS

•Syphilis, Chicken pox, Hand/foot/mouth disease (Coxsackie virus), Smallpox

DIAGNOSTIC TESTS & INTERPRETATION

•PCR from multiple skin lesions

•Culture is possible as specialized laboratories

TREATMENT

•Monkeypox is usually self-limiting but may be severe in some individuals, such as children, pregnant women or persons with immune suppression due to other health conditions.

•Smallpox vaccine may be of benefit

•Vaccinia immune globulin (VIG) maybe considered

•Anti-virals (Cidofovir, brincidofovir, tecovirimat) have been considered based upon outcomes in animal studies.

GENERAL MEASURES

•Supportive Care

•Patient Education: isolate until the scabs have fallen off and abstain from sex, including oral sex.

ALERT:

•Anyone caring for a person sick with monkeypox should use personal protective measures, including wearing a mask, and cleaning objects, and surfaces that have been touched.

ISSUES FOR REFERRAL

•For any potential case, contact the CDC at 770-488-7100

PROGNOSIS and COMPLICATIONS

•For those without immunodeficiency, the infection is usually self-limited.

•Severe scarring from healed lesions, Ocular complications (keratitis, corneal ulceration, and eventual blindness), pneumonia, respiratory failure, cyanosis, bacteremia, sepsis, hemodynamic shock and death.

REFERENCES:

•CDC: https://www.cdc.gov/poxvirus/monkeypox/index.html

•Multi-country monkeypox outbreak in non-endemic countries; https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON385

•Poxviruses; https://www.ncbi.nlm.nih.gov/books/NBK558959/