Monkeypox: Causes, Symptoms, Diagnosis and Treatment

Monkeypox is a viral zoonosis that resembles smallpox. The disease affects a person when the virus transmits from infected animals to humans. Since the symptoms resemble smallpox, most people can confuse with the deadly disease. It is because the disease is triggered by the type of orthopoxvirus that triggers smallpox. With the eradication of smallpox in 1980, the virus triggering monkeypox has emerged as the most significant one causing discomfort to people. Most doctors recommend the use of smallpox vaccine to prevent the disease or reduce its severity. With the smallpox vaccine ceased to exist for public use, people find it difficult to find an alternative cure for the disease. The infectious disease mostly occurs in West and Central Africa, usually near the tropical rainforests.

History Of Monkeypox

Monkeypox As the name suggests, the virus was identified first in a monkey. In 1958, scientists detected the type of virus in crab-eating monkeys. Scientists used the monkey species as laboratory animals for neurological experiments. The virus has double-stranded DNA and belongs to the Poxviridae family that targets humans. Scientists identified the first case of the virus in humans in 1970. A nine-year-old boy in the Democratic Republic of the Congo (earlier known as Zaire) exhibited the signs of the disease that mimicked smallpox. It baffled scientists as the region successfully eliminated smallpox in 1968. Tests detected the specific orthopoxvirus causing the disease. Since 1970, several regions of rural, rainforest in Africa reported similar cases. It has affected several countries in the African continent like:

  • Cameroon
  • The Democratic Republic of the Congo
  • The central African Republic
  • Gabon
  • Liberia
  • Ivory Coast
  • Nigeria
  • Sierra Leone
  • The Republic of the Congo
  • South Sudan

Notable Monkeypox Outbreaks

Notable Monkeypox Outbreaks

Many cases of the virus outbreak have occurred from its discovery in 1958 to date. The notable outbreaks are:

2003 U.S.A Outbreak

For the first time in its history, the outbreak of virus occurred in the USA. It is the first case of the disease outside Africa. A young child suffered from symptoms of the disease after getting a bite from the prairie dog. The outbreak resulted in the infection affecting 71 people. The cases uncovered link of the infection to Gambian pouched rats imported by an exotic animal distributor in Texas.

2017-2019 Nigeria Outbreak

It is the largest documented outbreak of monkeypox affecting humans. The disease caused the West African clade of the virus to spread to several states. The outbreak also indicated the evidence of secondary human-to-human transmission.

Monkeypox Vs Smallpox

The appearance of the disease mimics smallpox. But, it is milder and less infectious compared to smallpox. While smallpox is eradicated from the world, monkeypox is triggered by a virus from the orthopoxvirus family. Smallpox is an easily transmittable disease with a high rate of fatality as 30% of the infected people die. The last known case of smallpox occurred in 1977. So, in 1980, the WHO (world health organization) declared that the disease is completely eradicated from the world. The global vaccination campaign helped eradicate smallpox, the contagious and deadly disease. In earlier times, the health department in different countries suggested compulsory and routine vaccinia-based vaccine for smallpox. The vaccination not just prevented smallpox, but also monkeypox. With no vaccination for smallpox, people in West and Central Africa are now vulnerable to the less infectious orthopoxvirus.

Since you have no vaccine for smallpox, you may wonder how to combat other diseases triggered by orthopoxvirus. Scientists around the world working in the global health sector remain cautious to avoid reappearance of smallpox due to laboratory accidents, bio-war or natural mechanisms. To prepare the world for such reemergence, scientists are trying to develop newer vaccines, antiviral agents, and the latest diagnostic method to detect the case early. Scientists have developed a third-generation vaccinia vaccine and antivirals to combat diseases triggered by orthopoxvirus.

Causes Of Monkeypox

The disease is caused by the Monkeypox virus. The virus belongs to the orthopoxvirus group. The members of the genus of the virus are responsible for causing infection in humans like cowpox virus, vaccinia or variola (smallpox). The disease is commonly found in Cameroon. In the African country, scientists have uncovered two distinct genetic clades of orthopoxvirus triggering the disease. The two clades are:

  • West African Clade
  • Congo Basin Clade

Congo Basin clade is the more transmissible and virulent one compared to the other. Scientists have found the two types of virus clades in Cameroon, which point to the country as the geographical division.

Transmission Of Monkeypox

Transmission Of Monkeypox

The disease is found in African regions. The viral infection is found in many animals. So, the natural reservoir of the orthopoxvirus virus remains unclear. Most scientists suggest rodents are the likely source of infection. The virus infects the following animals:

  • Dormice
  • Rope Squirrels
  • Gambian poached rats
  • Tree squirrels
  • Different species of monkeys

Animal To Human Transmission

The primary cause of infection occurs when people come directly in contact with the infected animal’s bodily fluids, blood, mucosal/cutaneous lesions. Some people contract the infection when they eat meat or products from infected animals. The inadequately cooked meat of the infected animals poses a major risk.

Human-To-Human Transmission

The secondary infection is relatively limited. In most cases, human-to-human transmission occurs due to the following:

  • People coming in close contact with respiratory secretions of infected individuals.
  • Individuals who touch the skin lesions of the infected person.
  • Touch the surfaces recently contaminated by the infected person.
  • Transmission of the virus from an infected mother to fetus through the placenta (It is referred to as congenital monkeypox).

Respiratory secretions like droplets reach another person when the infected person coughs or sneezes. So, it requires face-to-face contact for the infection to transmit. It means healthcare workers or household members taking care of the infected person are at greater risk of secondary infection.

Symptoms Linked To Monkeypox

When you get exposed to the virus causing the disease, it takes six to thirteen days to see the signs associated with the condition. After the incubation period (the time taken for the infection to trigger symptoms), you can see the signs associated with the disease. The symptoms can appear anywhere from five to twenty-one days. The disease has two periods with different signs that include:

Invasion Period

The invasion period of the disease lasts from the day of contracting the disease to five days (0 to 5 days) with nonspecific symptoms. So, you can develop the following signs:

While the initial symptoms may mimic other conditions like measles, chickenpox, or smallpox, swelling of the lymph nodes is the distinctive feature of the disease. So, during the initial stages of the disease, doctors determine the problem due to the presence of lymphadenopathy.

Skin Eruptions

After one to three days after the appearance of fever, the infected person can develop skin eruptions. It usually develops in the face as well as extremities. So, instead of developing on the trunk, it also affects the following areas of the body:

  • More than 95% of people develop a rash on the face and chest.
  • 75% of the people develop a rash on soles of the feet and the palms of the hands.
  • 70% of the infected people develop rashes on the oral mucous membranes.
  • Around 30% of the people have rashes on genitalia.
  • Only 20% of the infected people develop pustules on cornea and conjunctiva.

Appearance Of The Rash

An infected person first develops a lesion with a flat base known as macules. Later, the macules can develop into papules. Papules are the firm and slightly raised lesions. It can also cause vesicles, which are lesions with clear fluids or pustules that contain yellowish fluid in it. As days progress, they ulcerate and crust over. It dries up after two to three weeks and falls off. People with infection can develop a few to thousand lesions on their skin. In severe cases, infected people can see the lesions merging to form a large section. Later, the large section of the skin sloughs off.

As you develop the rash, you can also see swelling of the lymph nodes. In some cases, the pox lesions that develop on the infected person becomes necrotic and starts destroying the sebaceous glands. So, it leaves a pox scar (a depression), which can fade as time passes. Unlike smallpox, people with infection may not see toxemia.

Complications Of Monkeypox

The disease is usually self-limited with infected people suffering from the symptoms from two to four weeks. Severe cases commonly affect children and people with a longer period of virus exposure. The duration of the disease also depends on your overall health status and the presence of other medical conditions as well as complications. People who suffer from the infection can expect the following complications:

The fatality rate among young children and people above the age of 50 years who suffer from the disease is high. People who live near or in the forested areas with low-level or indirect exposure to infected animals may develop an asymptomatic infection. So, people may not see any signs associated with the infection.

Diagnosis Of Monkeypox

Since the condition mimics several other skin conditions triggering rashes, you need to see a doctor confirm the diagnosis. Your doctor adopts the following methods to detect the problem conclusively.

Eliminate The Presence Of Other Diseases

The differential diagnosis is the first step your doctor adopts to determine the actual illness. So, your doctor performs tests to eliminate the following:

  • Syphilis
  • Bacterial skin infections
  • Measles
  • Chickenpox
  • Scabies
  • Medication-induced skin allergies

Physical Examination

The next steps are to perform a thorough physical examination to detect lymphadenopathy. It is the classical feature of the illness, which makes it different from the above-mentioned diseases. The disease causes adenopathy of the lymph nodes. The inflammation of the lymph nodes can lead to its enlarged size. So, swollen lymph nodes are the main indicators of the disease.

PCR Testing

To detect the condition conclusively, the doctor suggests for a polymerase chain reaction. It is the lab-based test known for its sensitivity and accuracy. To make a proper diagnosis, you need to provide a sample of the skin lesions (it includes, the roof or the vesicles/pustule fluid and dry crust). You need to take the sample needed for the PCR test just a few hours before the test. It is because of the short duration of viremia in the specimen. So, the timing of specimen collection holds significance.

Instructions For Testing Monkeypox

When the healthcare workers suspect the monkeypox virus, they need to collect the needed sample from the infected person as per the requirement. It is also essential to transport it safely to the laboratory with appropriate facility and capability. Since the conformation of the disease relies on the type and quality of the specimen provide and the type of laboratory tests, healthcare workers need to maintain caution. So, they must follow the national and international protocols/requirements for packing as well as the shipping of the specimen. Storing the lesion samples in a sterile, dry, and cool place is necessary while transporting the sample. The orthopoxviruses are not easy to detect using antigen and antibody detection methods due to its serologically cross-relative nature.

To detect orthopoxviruses in an infected person, serology and antigen detection are not recommended. People who have recently or remotely received vaccinia vaccine (like people who received vaccination before smallpox eradication or healthcare professionals with a high risk of coming in contact with orthopoxvirus) have chances of receiving false-positive results. For making a proper diagnosis, the healthcare professionals must provide the following details of the infected persons along with the specimen:

  • Date of commencement of the fever
  • The exact date of the beginning of rash on the skin
  • Specimen collection date
  • The current state of the infected person (stage of rash)
  • Age of the infected person

Treatment For Monkeypox Disease And Vaccination

No specific treatment is available for monkeypox. The only option used by the doctors to manage the condition is to use smallpox vaccination. Vaccinia vaccine has shown effective results in preventing the condition. So, people who have received smallpox vaccination can see 85% effectiveness in avoiding the disease or experience only mild symptoms due to the disease. It is effective because the disease is closely related to smallpox. So, it offers cross-protection.

In some cases, the doctor has seen positive results in patients undergoing human immune globulin or antiviral treatment. Remember, the treatment only offers relief from the symptoms. Your immune system needs to fight the virus to get relief.

Vaccination For Monkeypox

As the original vaccination developed for smallpox is not available for the general public, ongoing research tries to develop a new vaccine. While it is not available for public use, the new vaccinia-based vaccine has obtained the approval for preventing smallpox as well as monkeypox.

Identifying Natural Host Of Monkeypox

Along with trying to find a treatment for the disease, studies also try to find the various animal species that act as the natural host for the virus causing the disease. Laboratory experiments along with the field investigations suggest the following animals are susceptible to the infection and have a high risk of passing it to humans:

  • Gambian poached rats
  • Tree squirrels
  • Rope squirrels
  • Primate
  • Dormice

While doubts persist on the ability of the virus to infect different animals. So, further studies are essential to conclude how the virus is maintained in nature.

Preventing Monkeypox

The disease is easy to prevent an increase in awareness regarding the risk factors. By educating the people who are prone to the disease regarding the measures to take to reduce viral exposure. With increased awareness, people can devise the right preventive strategies to avoid the disease. Scientists are trying to determine the appropriateness and feasibility of using vaccines to prevent the condition and control it from becoming an outbreak. Different countries have developed or developing policies to use vaccines as a preventive measure to avoid infection in people who are at risk. So, people who work in the healthcare sector or come in contact with the virus (lab workers) need to use vaccines to avoid exposure.

Steps To Prevent Animal-To-Human Transmission

Since the infection occurs due to the primary contact between an infected animal and humans, it is essential to maintain caution. So, to avoid zoonotic transmission, you need to follow the steps suggested below:

  • Always avoid unprotected contact with wild animals. So, you need to use the suggested guidelines before touching sick or dead animals.
  • Use protection while touching blood, meat or other parts of the wild animals.
  • Never eat uncooked or raw food containing meat or other parts. Always thoroughly cook meat and other parts before eating it.

Steps To Reduce Risk Of Human-To-Human Transmission

Human-to-human transmission can occur, which results in the outbreak of the disease. So, you need to follow the steps suggested below to reduce the risk of transmission:

Active Monitoring

It is essential to monitor the areas prone to viral infection. Constant surveillance can help with the rapid identification of new cases. So, it aids in containing the outbreak.

Avoid Close Contact

The outbreak of the disease occurs when you come in close contact with people who suffer from the infection. So, healthcare workers and family members of an infected person face the risk of infection more. There are several measures that you can take to prevent infection. Therefore, you need to follow the pointers like:

  • You need to avoid coming in direct contact with animals that can harbor the virus. So, stay away from sick or dead animals found in the areas with a virus outbreak.
  • If you need to handle the sick or dead animals with the infection, then you need to use PPE (personal protective equipment). Using PPE is essential when healthcare workers care for infected people.
  • You need to avoid any contact with items or materials (like bedding) that has come in contact with the infected animal.
  • Isolate infected patients from healthy people or others who are at high risk of infection.
  • Practicing good hand hygiene is necessary after coming into contact with infected animals or humans. So, you need to use soap and water to wash your hands every time after handling infected humans or animals. If water is not available, using an alcohol-based hand sanitizer to eliminate the virus.

Instructions For Healthcare Workers

People working in the healthcare sector are more prone to coming into contact with infected people or virus specimens. So, people working in such areas need to follow the instructions like:

  • Healthcare workers coming in close contact with patients who suffer or are suspected of the viral infection. So, you need to handle the specimen with care and follow standard infection control protocols.
  • If possible, it is ideal to select people who have received vaccination against smallpox to care for the patients.
  • All the specimen taken from animals or people suspected of the disease needs proper handling. Only trained and experienced staff must handle the specimen.
  • Healthcare professionals should only test the specimen in a fully equipped laboratory. The lab must follow all the safety protocols while transporting or handling infectious substances.

Preventing Monkeypox Through Animal Trade Restrictions

It is important to follow the regulations put in place by the countries regarding the import of non-human primates to avoid the spread of the virus. Among the guidelines, the following holds high priority and avoids the spread of infection:

  • It is important to isolate the animals suspected of infection from others and place them in immediate quarantine to avoid the spreading of the virus.
  • If any animals come in contact with infected animals, then it is essential to place them in quarantine. Following the standard precaution is necessary. Observing the symptoms for at least a month is necessary.


Monkeypox is a rare disease that occurs due to direct contact with infected animals. But, the disease is preventable by maintaining some precautions. You must always avoid direct contact with infected animals (sick or dead). If you face more risk of contracting the disease, then it is better to get the vaccination. No vaccination is available commercially to avoid the disease. So, doctors suggest using smallpox vaccination to avoid the disease as it 85% chance of preventing the infection.

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