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Monkeypox

by Dragon Claw’s Researcher, 

Nurse Jill

The Monkeypox virus is one of 12 double-stranded DNA viruses that belongs to the Orthopoxvirus genus of the Poxviridae family. These include Smallpox, Camelpox, Cowpox, and Horsepox.

And Chickenpox you ask?

No, Chickenpox is from a completely different genus.  They are viral zoonotic diseases meaning they are passed from animals to humans. With the eradication of Smallpox in 1980 and the subsequent cessation of the Smallpox vaccine, Monkeypox has emerged as the most important Orthopoxvirus for public health and occurs mainly in Central and West Africa.

A recent Monkeypox outbreak has been declared a global emergency with more than 16,000 cases reported in 75 countries, most notably in Europe, where the risk is high. In Australia so far, 44 cases have been reported except in Western Australia and Tasmania. There are approximately 681 confirmed cases across 5 Provinces in Canada and these numbers are expected to continue to rise as the outbreak evolves.

Signs and Symptoms:

  • The incubation period (interval from infection to onset of symptoms) is usually from 6 to 13 days.
  • The invasion period (between 0–5 days) is characterized by fever, headache, swelling of the lymph nodes, back pain, myalgia (muscle aches) and intense asthenia (lack of energy).
  • The skin eruption begins within 1–3 days after the fever. The rash tends to be more concentrated on the face and extremities rather than on the trunk. It affects the Face, Palms of the Hands and Soles of the Feet, oral Mucous Membranes, Genitalia and Eye Cornea and Conjunctiva.
  • The rash evolves from macules (lesions with a flat base) to papules (slightly raised firm lesions), vesicles (lesions filled with clear fluid), pustules (lesions filled with yellowish fluid), and crusts which dry up and fall off. The number of lesions varies from a few to several thousand.

Monkeypox is usually a self-limited disease with the symptoms lasting from 2 to 4 weeks. Severe cases are related to the extent of virus exposure, patient health status and nature of complications. Underlying immune deficiencies may lead to worse outcomes.

Today people younger than 40 to 50 years of age may be more susceptible to Monkeypox.  Complications of monkeypox can include secondary infections, Bronchopneumonia, Sepsis, Encephalitis, and infection of the Cornea with ensuing loss of vision.

Transmission:

  • Animal-to-human (zoonotic) transmission can occur from direct contact with the blood, bodily fluids, or skin lesions of infected animals.
  • Human-to-human transmission can result from close contact with respiratory secretions, skin lesions of an infected person or recently contaminated objects. Transmission via droplet respiratory particles usually requires prolonged face-to-face contact.
  • Transmission can also occur via the Placenta from mother to Fetus, which can lead to Congenital Monkeypox or during close contact during and after birth.  The WHO (World Health Organization) is warning gay and bisexual men - particularly those with multiple sexual partners - as 98% of cases have so far occurred in men from those groups, with 95% of cases emerging from sexual activity.

Treatment:

Patients should be given fluids and food to maintain nutritional status and secondary bacterial infections should be treated with antibiotics. An antiviral agent known as Tecovirimat, developed for Smallpox, was licensed by the European Medicines Agency (EMA) for Monkeypox in 2022 based on data in animal and human studies.

Vaccination against Smallpox was demonstrated through studies to be about 85% effective in preventing Monkeypox and so prior Smallpox vaccination may result in milder illness. Unfortunately, the original (first-generation) smallpox vaccines are no longer available to the general public. A new vaccine based on a modified attenuated Vaccinia Virus (Ankara Strain) was approved for the prevention of Monkeypox in 2019. This is a two-dose vaccine for which availability remains limited.