Monkeypox is an emerging zoonotic disease caused by the monkeypox virus (MPXV), a member of the Orthopoxvirus genus in the Poxviridae family; it is a DNA virus similar to the smallpox virus. The incubation period in humans typically lasts 7 to 14 days, but it can range from 4 to 21 days. Depending on the mode of transmission, the major site of infection could be mucosal surfaces, skin, or the respiratory tract. The virus subsequently spreads through the lymphatic system, causing viremia; the classic pock lesions are the result of a skin infection.
Common Symptoms
The condition begins with a fever prodrome lasting 1-4 days, followed by headaches, muscle aches, and backache, as well as weariness, sweating, fatigue, and a cutaneal appearance. Skin rashes begin within 1-3 days of fever onset. The rash may develop on the face, inside the lips, hands, feet, chest, genitals, anus, or in the eyes. Lesions begin as a flat rash (macula) and then rise from the skin (papules), eventually taking on a “vesicle” appearance by filling with clear liquid. The clear liquid inside the vesicles turns yellowish, forming “pustules”. Pustules, crusts, and lesions diminish when the crusts fall. After the crust has fallen off, patients are termed noninfectious.
Lymphadenopathy
One characteristic that separates smallpox from monkeypox is lymphadenopathy. This usually happens when the fever starts, sometimes a few days before the rash starts. The submental, submandibular, cervical, and inguinal lymph nodes are typically the largest. Additionally, those who have been exposed may experience a sore throat, cough, and/or oral mucous membrane rash. However, observations have been made of nonspecific clinical presentations, lesions, and inflammation of the vaginal, conjunctival, and pharyngeal mucosae.
Vaginal Lesions
The latest outbreak of monkeypox presents with distinct clinical symptoms compared to the previous one. Historically, human monkeypox has caused rare vaginal lesions along with monomorphic pustular rashes. It is noteworthy that the primary symptom of monkeypox in the present outbreak is surprisingly vaginal rashes. Outside of Africa, the vaginal rash often appears before the generalized pustular rash. Gnitourinary involvement is widespread in MPXV infection and is often the basis for the consultation session, according to a prospective observational study of 14 individuals with monkeypox disease. This presentation suggests that a primary infection that generates a localized rash and, in some cases, a secondary widespread illness originates in the genital area. Furthermore, there is a possibility of misdiagnosis due to the similarities between the clinical signs and symptoms of monkeypox and syphilis.
Myopericarditis and Neurologic Symptoms
The present monkeypox outbreak has also been linked to various clinical pathology signs, such as myopericarditis and neurologic symptoms, in addition to primary genitourinary involvement. Myopericarditis was observed in a 40-year-old Caucasian man with proven MPXV infection by Sanromán Guerrero et al., 2023, underscoring the possibility of cardiovascular involvement as an MPXV infection consequence days after skin lesions first emerged. Additionally, there is early evidence for a broad spectrum of neurological symptoms associated with monkeypox, including anorexia, vomiting, nausea, agitation, altered consciousness, lethargy, malaise, headaches, and myalgia. According to reports, olfactory epithelium and infected circulatory monocytes/macrophages are the primary routes via which MPXV penetrates the central nervous system.
MPX is a self-limiting disease, and the severity of the disease is related to the degree of exposure to the virus, the patient’s health conditions, and the nature of its complications.
Difference for subclade IIb infection
When MPXV clade I or subclade IIa causes monkeypox, the typical rash that develops on the face, body, mucous membranes, palms of the hands, soles of the feet, and vesicles moves centrifugally from maculopapules to crusts. The clinical presentation of monkeypox includes fever, headache, lymphadenopathy, and/or malaise. Different from classical monkeypox, the clinical presentation of subclade IIb infection is characterized by a good prognosis, self-limiting but infectious skin lesions that usually appear at the genital, perineal/perianal, and/or perioral areas and are self-limiting before fever, lymphadenopathy, and malaise develop. The typical sign of a generalized illness is a rash, which has not been extensively reported in this outbreak.
References
- Altindis, M., Puca, E., & Shapo, L. (2022). Diagnosis of monkeypox virus–An overview. Travel medicine and infectious disease, 50, 102459.
- Gong, Q., Wang, C., Chuai, X., & Chiu, S. (2022). Monkeypox virus: a re-emergent threat to humans. Virologica Sinica, 37(4), 477-482.
- Kaler, J., Hussain, A., Flores, G., Kheiri, S., & Desrosiers, D. (2022). Monkeypox: a comprehensive review of transmission, pathogenesis, and manifestation. Cureus, 14(7).
- Hraib, M., Jouni, S., Albitar, M. M., Alaidi, S., & Alshehabi, Z. (2022). The outbreak of monkeypox 2022: An overview. Annals of medicine and surgery, 79, 104069.
- Sepehrinezhad, A., Ashayeri Ahmadabad, R., & Sahab-Negah, S. (2023). Monkeypox virus from neurological complications to neuroinvasive properties: current status and future perspectives. Journal of Neurology, 270(1), 101-108.
- Letafati, A., & Sakhavarz, T. (2023). Monkeypox virus: A review. Microbial Pathogenesis, 176, 106027.
- Sanromán Guerrero, M. A., Sánchez, E. H., Ruanes, B. D. N., Fernández-González, P., Ugalde, S. A., Leal, A. G., … & Vivancos-Gallego, M. J. (2023). Case report: From monkeypox pharyngitis to myopericarditis and atypical skin lesions. Frontiers in cardiovascular medicine, 9, 1046498.
