infectious diseases
Mpox (Monkeypox)
Introduction
Mpox (monkeypox)is caused by the monkeypox virus, anorthopoxvirusstructurally related to the smallpox virus. Patients present with a vesicular or pustular rash that may be painful and often with fever, malaise, and lymphadenopathy. Diagnosis is by polymerase chain reaction (PCR). Treatment is generally supportive and potentially with antiviral drugs. Prevention involves vaccination. Monkeypox virus, like Smallpox , is a member of the Historically, human disease was mainly limited to sporadic cases and occasional epidemics, mainly in Africa. Most reported cases have been in the Democratic Republic of the Congo. Since 2016, confirmed cases have also been reported in Sierra Leone, Liberia, Central African Republic, Republic of the Congo, and Nigeria. A dramatic increase in incidence in Africa since 2000 is thought to be due to the cessation of smallpox vaccination in 1980; people who have receivedsmallpox vaccine, even > 25 years prior, are at reduced risk of mpox. Cases of mpox in Africa are also increasing because people are encroaching more and more on the habitats of animals that carry the virus. Prior to 2022, cases outside of Africa were directly linked to travel to western and central Africa or animals imported from the region. A notable outbreak of mpox occurred in the United States in 2003, when infected rodents imported as pets from Africa spread the virus to pet prairie dogs, which then infected people in the Midwest. The outbreak involved 37 confirmed and 10 probable cases in 6 states, but there were no deaths ( References ). ). The number of new cases has dramatically decreased since the peak in August 2022. All cases associated with the 2022 global outbreak have been the West African clade. Cases have been reported primarily in men who have sex with men, but mpox should be considered in anyone who presents with a rash consistent with mpox ( References , In animal-to-person transmission, mpox is probably transmitted via body fluids, including salivary or respiratory droplets or contact with wound exudate. This can occur through bites or scratches from an animal or through preparation and consumption of infected animal meat. Person-to-person transmission occurs through prolonged close contact. Routes of transmission include respiratory droplets via prolonged face-to-face or intimate physical contact, direct contact with infectious lesions or other bodily fluids, and fomites via contact with clothing or linens contaminated with lesion crusts or bodily fluids. Maternal-fetal transmission can occur via the placenta. It is currently unknown whether transmission can occur through semen or vaginal fluids. In the 2022 outbreak, many cases appear due to transmission during sexual or intimate encounters, but this is likely through direct contact with infectious lesions or respiratory secretions. The incubation period is 1 to 2 weeks but can be as long as 3 weeks. People are infectious from the time symptoms start until all lesions have crusted and scabs have fallen off to reveal healthy skin. This typically takes 2 to 4 weeks. Based on a transmission study in Africa, the overall secondary attack rate following contact with a known human source is 3%, and attack rates up to 50% have been reported in people living with a mpox-infected person ( References ). Transmission in hospital settings has been documented in an endemic setting. One case of transmission to a healthcare worker has been reported ( 