Monkeypox is caused by the monkeypox virus (MPXV), a member of the genus Orthopoxvirus. The name monkeypox was given as the disease was first recognized in an outbreak of vesicular lesion amongst captive monkeys in 1958. Human disease was first observed in early 1970s in West and Central Africa particularly Congo Basin countries after the eradication of smallpox from these regions. Monkeypox is presently the most important Orthopoxvirus for humans after the eradication of smallpox virus and cessation of smallpox vaccine. The disease in human resembles clinically with smallpox but in a milder form and its cross-protection by smallpox vaccine makes the virus more relevant clinically.

Epidemiology: The primary animal reservoir host for MPXV remains unknown, however, evidence of infection implicates squirrels and rodents. Infection in monkeys and humans is incidental.

The disease in humans is rare and occurs mostly as zoonosis. The primary zoonotic infection occurs by direct or indirect contact with the body fluids of the infected animals through handling, bites or scratches. The secondary human to human transmission occurs through infected respiratory droplets or direct or indirect contact with infected lesion material, body fluids or contaminated materials or surfaces. The virus enters through respiratory tract or through broken skin or mucosa (Fig. 1).

Fig1. Monkeypox virus: Modes of transmission

Monkeypox usually considered as a geographically restricted disease being confined to West and Central Africa particularly in the tropical rain forest areas. Two different monkeypox virus clades exist: (1) Congo Basin clade which is prevalent in Central Africa, and (2) West Africa clade which is prevalent in West Africa. Both clades are found in Cameroon. Congo Basin clade has been found to be more virulent and transmissible.

The first human case was reported in the year 1970 in a 9-year-old boy in the Democratic Republic of Congo. Since 1970, several sporadic and outbreaks have been reported in central and West African regions. However, the number of human cases is rising in recent years with possible human-to-human trans mission. Amongst the large outbreaks of human poxvirus infection, outbreaks in Democratic Republic of Congo (previously known as Zaire) in 1996–97 affecting >500 people and in 2017–18 in Nigeria affecting >100 people are of concern.

Imported human monkeypox outbreaks: The first report of MPXV infection in western hemisphere was reported in USA in 2003 where >80 people from different states were affected. The infection was traced to contact with prairie dogs that were kept along with the exotic rodents imported from Africa.

Imported cases were reported from Israel in 2018, from United Kingdom in 2018 and 2019 and from Singapore in 2019 in individuals who had travelled to Nigeria.

Clinical features in MPXV infection is similar to smallpox. The incubation period is 7–17 days. The symptoms start with prodrome of fever, headache, myalgia, followed by development of lesion on skin and mucosa within 1–3 days. Lesions are maculopapular to start with and become fluid filled vesicles and pustules and finally become crusted by 10 days. Crust disappears within 3 weeks.

Pronounced lymphadenopathy is common and is the clinical distinguishing feature than smallpox.

Smallpox and Monkeypox Vaccines

Currently two vaccines have been licensed in USA for prevention of smallpox, ACAM2000 and JYNNEOS^TM and the later one JANNEOS^TM is also licensed for prevention of monkeypox. Both are live virus preparation.

ACAM2000 is a replicating virus, given by skin prick. Successful inoculation leads to development of lesion at the site. As the virus propagates at the site, it can spread to other parts of the body and also to other persons. Individuals who receive this vaccine are advised to take adequate precaution to prevent spread of vaccine virus. The present recommendation by CDC and Advisory Committee for Immunization Practice (ACIP) is for individuals who are at high-risk for smallpox like laboratory personnel working on orthopoxviruses and military personnel.

JYNNEOS^TM (also named Imvamune or Imvanex) is also a live vaccinia virus containing Modified Vaccinia Ankara (MVA). Unlike ACAM2000, it is non-replicating, given in two doses, at 4 weeks apart by subcutaneous route. There is no risk of spread of vaccine virus to other parts of body or to other people.

Efficacy of these vaccines is around 85% in preventing against monkeypox when given before exposure. In case of postexposure, vaccine is recommended within 4 days of exposure to prevent the disease. When given between 4 and 14 days of exposure, it may reduce the disease severity. Table 1 summarizes the important facts on human monkeypox virus infection.

Table1. Important facts of human monkeypox virus infection

اخر الاخبار

اخبار العتبة العباسية المقدسة

قسم الشبابيك: تقديم أكثر من 50 ألف وجبة طعام لزائري الأربعين

قسم الشؤون الخدمية يطلق حملة تنظيف لمنطقة باب بغداد بعد انتهاء زيارة الأربعين

قسم الشؤون الفكرية: نحو 5000 مستفيد من خدمات محطة مجمّع سيد الماء الثقافي

مجمع أبي الفضل العباس (عليه السلام): أكثر من 30 ألف مستفيدة من الخدمات الصحية في زيارة الأربعين

المزيد

الآخبار الصحية

9 أسباب شائعة للرؤية الضبابية يجب معرفتها

تتناولها كل يوم.. 10 وجبات شائعة غنية بـ"السكر الخفي"

7 أسباب شائعة لفقدان الشهية لدى كبار السن

7 فواكه قد تسبب قفزة مفاجئة في سكر الدم

المزيد

الآخبار التكنلوجية

هل تشغيل تكييف السيارة على "الحد الأقصى" ضار؟

دور المكابح في تحسين كفاءة استهلاك الوقود بالسيارات

بالذكاء الاصطناعي.. باحثون يبتكرون مضادات جديدة لنوعين من العدوى البكتيرية

فيتامين سي والتجاعيد.. طبيب يكشف وقت الاستخدام الصحيح

المزيد

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