Things you need to know about mpox (I)
What is mpox?
Mpox, formerly known as monkeypox, is a zoonotic infectious disease caused by the monkeypox virus (MPXV), and is characterized by fever, a rash and swollen lymph nodes.
The virus was first discovered in monkeys in 1958, and was first isolated from a specimen of a suspected smallpox patient from the Democratic Republic of the Congo in 1970, which was the first confirmed human mpox case.
What are its transmission routes?
Sources of mpox infection include humans, rodents, monkeys, apes and other primates that are infected with the MPXV. The virus usually invades the human body through mucous membranes and damaged skin.
It is mainly transmitted through direct contact with skin lesions or the mucous membranes of those infected. Sometimes it can spread through contact with virus-contaminated items, long-term close-range inhalation of respiratory droplets of infected individuals, and contact with respiratory secretions, lesion exudates, blood and other body fluids of infected animals, or through bites or scratches from infected animals.
How has mpox spread since 2022?
Until 2021, mpox had been generally endemic in Central and West Africa, mainly through contact with infected animals. At that time, the disease rarely spread to other countries and regions through family or travel, as the resulting human-to-human transmission chain was relatively short.
The outbreaks in many countries that have taken place since May 2022 are mainly found among men who have sex with men (MSM). Most of the cases are young and middle-aged men. The virus was spread through large gatherings and subsequent MSM in the community, even to many other countries and regions around the world.
What are the main symptoms?
The incubation period of mpox is 5 to 21 days, most infected cases will show symptoms 6 to 13 days after exposure. Symptoms such as fever, headache, back pain, muscle aches, and swollen lymph nodes may appear in the early stage of the infection.
Rash and enanthema usually appear after the fever subsides. For some cases, rash appears before other symptoms. The rash usually goes through stages of macule, papule, vesicle, pustule, scab and shedding of the scab. Different forms of rash may exist simultaneously, and some may be itchy or painful. The rash can appear on the body parts such as oral and throat mucosa, the anus, genital, conjunctiva and cornea.
The course of mpox is about 2 to 4 weeks, and it may be longer in immunocompromised patients. As a self-limiting disease, the symptoms will disappear in most cases. However, in some cases, especially children, pregnant women and people with weak immunity, the infected can become severely ill and lose their lives after infection.
What are the characteristics of mpox cases since 2022?
During the outbreaks that have taken place in many countries since 2022, most of the cases have seen mild clinical manifestations. Some cases have no systemic symptoms, with their rash being limited to the genitals and anorectal mucosa. Reported deaths mainly occurred in people with hypoimmunity, such as HIV-infected patients who had not received treatment. Since 2022, the fatality rate of cases in non-endemic areas around the world is about 0.1 percent.
Where can I get tested for mpox?
At present, there is no self-test method for mpox. Someone suspected to be infected had better go to the hospital. When seeing a doctor, report the symptoms and take a sample for testing.
How can the mpox infection be treated?
Current therapy is mainly symptomatic and supportive treatment, which is used to prevent secondary bacterial infections.