Clinical features
The clinical symptoms of MPXV infection are similar to those of other
orthopoxviruses, but lymphadenopathy is a unique hallmark of MPXV
infection [56]. There are three periods of human MPXV infection:
incubation, onset, and rash periods. The incubation period is about 6 to
13 days and may be up to 21 days. The onset period lasts about 5 days
and has atypical symptoms, including fever, chills, sweating, headache,
sore throat, muscle pain, back pain, fatigue, and lymphadenopathy. The
rash period usually begins after 1 to 3 days of fever and
lymphadenopathy. The rash may initially start in the mouth, then on the
face, and then appear elsewhere in the body. The rash goes through
several stages of change, evolving in turn from maculae to papules,
vesicles, and pustules, which may appear simultaneously in different
stages, eventually crusting and healing [57]. However, in the 2022
MPX pandemic, many patients presented with atypical disease
manifestations such as anal pain and bleeding, and these lesions were
usually located in the genital, perineal, or perianal regions [2].
MPX is a self-limiting disease, the duration of its symptoms usually
lasts 5 to 21 days, and most MPXV-infected patients will heal on their
own within 2 to 4 weeks [58]. However, in some cases, it can make
the condition worse and may even lead to life-threatening complications.
For example, those patients with untreated HIV infection who are
co-infected with MPXV have a longer duration of disease, more severe
lesions, and a higher incidence of secondary bacterial skin infections
and genital ulcers [59]. The overall mortality rate of MPXV
infection varies depending on the age of the patient, the branch of the
virus, and the region of the outbreak.