Understanding Monkeypox: Symptoms, Transmission, and Prevention

In this article, we will delve into the monkeypox virus’s symptoms, modes of transmission, historical context, and prevention strategies. We will also explore the public health implications of recent outbreaks and consider what the future might hold for managing this disease.

What is Monkeypox?

Monkeypox is a viral disease that occurs primarily in remote areas of Central and West Africa, near tropical rainforests, where humans are more likely to come into contact with infected animals. The virus was first discovered in laboratory monkeys, which led to its name. However, rodents such as squirrels, Gambian pouched rats, and dormice are considered the likely primary animal reservoir. The virus has two distinct genetic clades: the Central African (Congo Basin) clade and the West African clade. The Central African strain is generally more severe, with higher mortality rates and greater potential for human-to-human transmission.

Since the eradication of smallpox in 1980, monkeypox has emerged as the most significant orthopoxvirus in humans. The cessation of smallpox vaccination campaigns has left a larger portion of the global population susceptible to monkeypox. As immunity from the smallpox vaccine wanes, the risk of monkeypox outbreaks rises, particularly in regions with close human-animal interaction.

Symptoms of Monkeypox

The symptoms of monkeypox are similar to, but milder than, those of smallpox. However, monkeypox has a notable feature that differentiates it from smallpox: swollen lymph nodes, also known as lymphadenopathy. Symptoms typically appear within 5 to 21 days following exposure, and the disease progresses in two stages:

1. The Invasion Period (0–5 Days)

This initial stage of infection is characterized by a number of non-specific symptoms that resemble other viral infections such as influenza. These symptoms include:

Fever: The body’s initial response to the virus.

Severe Headache: Often intense and debilitating.

Muscle Aches: Generalized myalgia, particularly in the back and legs.

Exhaustion and Fatigue: This is often significant, with the patient feeling profoundly weak.

Swollen Lymph Nodes: Lymphadenopathy typically occurs in the neck, armpits, or groin. This is a distinguishing feature of monkeypox compared to smallpox.

2. The Eruptive Stage (1–3 Days After the Onset of Fever)

The second phase of monkeypox is marked by the appearance of a rash, which is the most distinctive clinical feature of the disease. The rash typically begins on the face and then spreads to other parts of the body, particularly the hands and feet, including the palms and soles. The rash progresses through several stages, from macules (flat lesions) to papules (raised lesions), vesicles (fluid-filled blisters), pustules (lesions filled with pus), and finally scabs that fall off after the lesions heal.

The rash can be painful and disfiguring, with some patients experiencing lesions inside the mouth, eyes, and genitalia. Although the symptoms generally resolve within 2 to 4 weeks, severe cases can occur, especially in children, pregnant women, and individuals with weakened immune systems. In some cases, complications such as secondary bacterial infections, respiratory distress, or even encephalitis (inflammation of the brain) may develop, necessitating hospital care.

Transmission of Monkeypox

Monkeypox is primarily a zoonotic disease, meaning it spreads from animals to humans. However, human-to-human transmission is also possible, though it requires closer contact than many other viral diseases like influenza or measles. Understanding the various transmission pathways is crucial to preventing outbreaks.

Animal-to-Human Transmission

In regions where monkeypox is endemic, contact with infected animals is the primary route of transmission. People may contract the virus through:

Direct Contact with Animal Fluids or Lesions: This can occur when hunting, skinning, or butchering animals such as rodents or primates that carry the virus.

Bites or Scratches from Infected Animals: In the wild, contact with the saliva, blood, or other fluids of infected animals can transmit the virus to humans.

Consumption of Under-cooked Meat from Infected Animals: Bushmeat, or meat from wild animals, is a common food source in many parts of Africa, but it carries the risk of zoonotic disease transmission if improperly handled or cooked.

Human-to-Human Transmission

Although less common, human-to-human transmission does occur, particularly during close, prolonged contact. Transmission typically happens through:

Respiratory Droplets: Monkeypox can spread via large respiratory droplets, which require extended face-to-face interaction to transmit. This is why most human-to-human transmissions occur among family members or healthcare workers caring for infected individuals.

Contact with Bodily Fluids or Skin Lesions: The virus can spread through direct contact with the rash, bodily fluids, or contaminated materials such as bedding or clothing.

Vertical Transmission: In rare cases, the virus can spread from a pregnant woman to her fetus via the placenta.

Human-to-human transmission is generally considered inefficient compared to more contagious diseases like COVID-19, but it remains a significant concern in outbreak scenarios.

Prevention of Monkeypox

Preventing monkeypox requires a combination of strategies aimed at reducing animal-to-human transmission, controlling human outbreaks, and promoting vaccination in high-risk areas. Here are the primary methods of prevention:

1. Avoid Contact with Wild Animals

In areas where monkeypox is endemic, avoiding contact with wild animals is the most effective preventive measure. This includes not handling sick or dead animals and avoiding hunting or consuming bushmeat. Public education campaigns are essential in these regions to raise awareness about the risks associated with wildlife exposure.

2. Practicing Good Hygiene

Handwashing is a simple but effective measure to prevent the spread of monkeypox. Individuals should wash their hands frequently with soap and water, especially after coming into contact with animals or sick people. Alcohol-based hand sanitizers can be used when soap and water are unavailable.

3. Isolation and Quarantine of Infected Individuals

Infected individuals should be isolated to prevent the spread of the virus. Health authorities may implement quarantine measures for people who have been in close contact with an infected individual during an outbreak. Isolation and proper handling of contaminated materials, such as bedding and clothing, are essential to reduce secondary infections.

4. Personal Protective Equipment (PPE)

Healthcare workers and those caring for infected individuals should use appropriate PPE, including gloves, masks, and protective clothing, to prevent direct contact with the virus. In healthcare settings, ensuring that medical staff have access to adequate protective measures is vital for controlling outbreaks.

5. Vaccination

The smallpox vaccine has demonstrated cross-protection against monkeypox due to the similarities between the viruses. Though routine smallpox vaccination ended decades ago, in regions with ongoing monkeypox outbreaks, vaccination is recommended for healthcare workers and people who may be at higher risk of exposure. The newer generation of smallpox vaccines, such as the JYNNEOS vaccine, has been approved for use against both smallpox and monkeypox in some countries, offering a safer option with fewer side effects than older vaccines.

6. Animal Control

Controlling the animal population in areas prone to monkeypox outbreaks can help reduce the risk of zoonotic transmission. Reducing human contact with wild animals and improving food safety measures, particularly in regard to the handling and cooking of bushmeat, are critical components of animal control efforts.

Treatment and Management of Monkeypox

Currently, there is no specific treatment for monkeypox, and care is generally supportive, aimed at alleviating symptoms and preventing complications. However, several antiviral medications originally developed for smallpox have shown some efficacy against monkeypox in clinical settings. These include:

Tecovirimat (TPOXX): This antiviral drug is approved for treating orthopoxvirus infections, including monkeypox. It works by targeting the viral protein needed for the virus to exit infected cells, thereby reducing viral spread.

Cidofovir and Brincidofovir: These drugs, typically used for other viral infections, have shown some promise in treating severe cases of monkeypox. However, their use is often limited by potential side effects.

For severe cases, particularly those with secondary bacterial infections, hospitalization may be necessary. In such instances, antibiotics may be prescribed, and respiratory support may be provided to patients who develop complications like pneumonia.

Global Impact and Public Health Response

Historically, monkeypox was largely restricted to parts of Africa. However, in recent years, there have been outbreaks in countries far from its endemic regions. In 2022, an unprecedented number of monkeypox cases were reported across Europe, North America, and Asia, raising alarms about the global spread of the virus. International travel, increased human-wildlife interaction, and the decline in immunity due to the cessation of smallpox vaccination programs have all contributed to these outbreaks.

The World Health Organization (WHO) and national health agencies have called for increased surveillance and preparedness to manage the rising number of monkeypox cases. Efforts are underway to strengthen public health infrastructure, develop better diagnostic tools