MONKEYPOX: A NEW THREAT

Pox defines as a disease, caused by virus which is characterized by skin lesions, pustules, or rashes. Generally, pox caused by viruses in the Poxviridae family and other related viruses. There are several types of pox, such as Chickenpox, Small pox, Monkey pox, cowpox etc.

In recent period Monkeypox or Mpox is the most talked topic. Basically, monkeypox is caused by the Monkeypox virus, a member of the orthopoxvirus genus. It is similar to smallpox but generally less severe.

Outbreak:

Monkeypox was first identified in 1958 when outbreaks of a pox-like disease occurred in monkeys kept for research, hence the name "monkeypox." Here’s a timeline of key events in the history of monkeypox:

1958: The monkeypox virus was first identified in laboratory monkeys in Denmark.

1970: The first human case of monkeypox was recorded in the Democratic Republic of Congo (DRC). This occurred during intensified efforts to eradicate smallpox, leading to heightened surveillance for pox-like diseases. Monkeypox cases in humans were sporadically reported afterward, mostly in rural, rainforest regions of Central and West Africa.

1980s–1990s: Monkeypox continued to be observed in African countries, with cases predominantly found in the DRC. It was recognized as an emerging zoonotic disease due to its transmission from animals to humans.

2003: The first outbreak outside Africa occurred in the United States. The virus spread through imported African rodents that infected pet prairie dogs, which then transmitted the virus to humans. Over 70 cases were reported, highlighting monkeypox's potential to spread outside its usual geographic region.

2017: Nigeria experienced its largest monkeypox outbreak after decades of no reported cases. This outbreak led to increased awareness and surveillance, revealing that the virus was more widespread and possibly reemerging due to factors like deforestation and human-animal interaction.

2022 Global Outbreak: In May 2022, cases of monkeypox were reported in multiple countries outside of Africa, with infections spreading predominantly through close physical contact rather than animal exposure. The World Health Organization (WHO) declared this outbreak a "Public Health Emergency of International Concern" in July 2022. This was the first time monkeypox spread widely through human-to-human transmission outside Africa, primarily affecting men who have sex with men. This outbreak also led to a surge in demand for the Jynneos (Imvanex) vaccine, initially developed for smallpox but effective against monkeypox.

Renaming as "Mpox": In late 2022, due to concerns about stigma and to standardize naming conventions, the WHO recommended changing the disease name from "monkeypox" to "mpox."

Types of Monkeypox:

Monkeypox is primarily divided into two distinct clades based on geographic and genetic differences. These are:

Clade I. Clade I is endemic to Central Africa. It tends to cause more serious illness than clade II. It is associated with higher mortality rates and more pronounced symptoms, such as a more extensive rash and larger, fluid-filled lesions. Human-to-human transmission is more common with this clade.

Clade II. Clade II is endemic to East Africa. There’s been a global outbreak of clade II mpox since 2022. It’s less likely to be fatal than clade I. 

Sign and Symptoms:

The sign and symptoms of monkeypox typically appearing in 1 to 2 weeks after exposure. Common symptoms of monkeypox may include:

• rash
• fever
• sore throat
• headache 
• muscle aches 
• back pain 
• low energy 
• swollen lymph nodes.  

For some people, the first symptom of mpox is a rash, while others may have fever, muscle aches or sore throat first.  

The mpox rash often begins on the face and spreads over the body, extending to the palms of the hands and soles of the feet. It can also start on other parts of the body where contact was made, such as the genitals. It starts as a flat sore, which develops into a blister filled with liquid that may be itchy or painful. As the rash heals, the lesions dry up, crust over and fall off. 

Some people may have one or a few skin lesions and others have hundreds or more. These can appear anywhere on the body including: 

• palms of hands and soles of feet 
• face, mouth and throat 
• groin and genital areas 
• anus.

Some people also have painful swelling of their rectum (proctitis) or pain and difficulty when peeing (dysuria) or when swallowing. 

Transmission:

This pox mainly spreads through close contact with an infected person, animal. Some transmission methods of mpox is,

A. Human to Human transmission

In human to human transmission this may occur by

Direct Contact: Touching skin lesions, body fluids like saliva or respiratory secretions of an infected person.

Respiratory Droplets: Prolonged face to face contact can spread the virus through large respiratory droplets.

Contaminated Objects: Touching objects or surface, such as bedding, clothing or towels contaminated with fluid from monkeypox lesions.

Intimate Contact: Close physical interactions, including sexual contact can transmit the virus.

B. Animal to Human Transmission:

Bite or Scratch from Infected Animals: Primarily from rodents or small mammals that carry the virus.

Direct Contact with infected animal: Touching blood, bodily fluids or lesions of an infected animal.

Eating Undercooked Meat: Consuming undercooked meat or other products from infected animals can also be a source.

Treatment:

The treatment of mpox generally focuses on managing symptoms, as the infection is often self-limiting and resolves in 2-4 weeks. However, there are specific treatments and supportive care measures used in cases of sever infection or when complications areise.

A primary antiviral known as Tecovirimat is approved for mpox in some countries.

Vaccine

Historically, smallpox vaccine had been reported to reduce the risk of mpox among previously vaccinated persons in Africa. The decrease in immunity to poxviruses in exposed populations is a factor in the increasing prevalence of human mpox. It is attributed to waning cross-protective immunity among those vaccinated before 1980, when mass smallpox vaccinations were discontinued, and to the gradually increasing proportion of unvaccinated individuals.

As of August 2024, there are four vaccines in use to prevent mpox. All were originally developed to combat smallpox.

MVA-BN (marketed as Jynneos, Imvamune or Imvanex) manufactured by Bavarian Nordic. Licensed for use against mpox in Europe, United States and Canada.

LC16 from KMB Biologics (Japan) – licensed for use in Japan.

OrthopoxVac, licensed for use in Russia and manufactured by the State Research Center of Virology and Biotechnology VECTOR in Russia

ACAM2000, manufactured by Emergent BioSolutions. Approved for use against mpox in the United States as of August 2024.

The MVA-BN vaccine, originally developed for smallpox, has been approved in the United States for use by persons who are either considered at high risk of exposure to mpox, or who may have recently been exposed to it. The United States Centers for Disease Control and Prevention (CDC) recommends that persons investigating mpox outbreaks, those caring for infected individuals or animals, and those exposed by close or intimate contact with infected individuals or animals should receive a vaccination.

This article is taken from the Galen Gazette, November 2024, Issue No. 07.  The author, Sakib Hasan, is a sixth-semester pharmacy student at Comilla University.