Monkeypox

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Monkeypox

What is Monkeypox

Monkeypox is a rare disease caused by infection with the monkeypox virus.
Monkeypox virus belongs to the Orthopoxvirus genus in the family Poxviridae.
The Orthopoxvirus genus also includes variola virus (which causes smallpox), vaccinia virus (used in the smallpox vaccine), and cowpox virus.
Monkeypox was first discovered in 1958 when two outbreaks of a pox-like disease occurred in colonies of monkeys kept for research.

Hence the name ‘Monkeypox.’

The first human case of monkeypox was recorded in 1970 in the Democratic Republic of the Congo (DRC) during a period of intensified effort to eliminate smallpox.
Since then, Monkeypox has been reported in people in several other central and western African countries: Cameroon, Central African Republic, Cote d’Ivoire, the Democratic Republic of the Congo, Gabon, Liberia, Nigeria, Republic of the Congo, and Sierra Leone.
The majority of infections are in the Democratic Republic of the Congo.
Monkeypox cases have occurred outside Africa linked to international travel or imported animals, including patients in the United States, Israel, Singapore, and the United Kingdom.
The natural reservoir of monkeypox remains unknown. However, African rodents and non-human primates (like monkeys) may harbour the virus and infect people.

The pathogen of Monkeypox

Monkeypox virus is an enveloped double-stranded DNA virus that belongs to the Orthopoxvirus genus of the Poxviridae family.
There are two distinct genetic clades of the monkeypox virus: the central African (Congo Basin) clade and the West African clade.
The Congo Basin clade has historically caused more severe disease and was thought to be more transmissible.
The geographical division between the two clades has been in Cameroon, the only country where both virus clades have been found.

The natural host of the monkeypox virus

Various animal species have been identified as susceptible to the Monkeypox virus.
This includes rope squirrels, tree squirrels, Gambian pouched rats, dormice, non-human primates and other species.
Uncertainty remains on the natural history of the Monkeypox virus, and further studies are needed to identify the same reservoir(s) and how virus circulation is maintained in nature.

Outbreaks of monkeypox

Human monkeypox was first identified in humans in 1970 in the Democratic Republic of the Congo in a 9-year-old boy in a region where smallpox had been eliminated in 1968.
Since then, most cases have been reported from rural.
Rainforest regions of the Congo Basin, particularly in the Democratic Republic of the Congo
Human cases are increasingly reported from across central and west Africa.
Since 1970, human cases of Monkeypox have been reported in 11 African countries: Benin, Cameroon, and the Central African Republic.
The Democratic Republic of the Congo, Gabon, Cote d’Ivoire, Liberia, Nigeria, the Republic of the Congo, Sierra Leone and South Sudan.
The actual burden of monkeypox is not known.

See this example

For example, in 1996–97, an outbreak was reported in the Democratic Republic of the Congo with a lower case fatality ratio and a higher attack rate than usual.
A concurrent outbreak of chickenpox (caused by the varicella virus, which is not an orthopoxvirus) and Monkeypox was found.
This could explain real or apparent changes in transmission dynamics in this case.
Since 2017, Nigeria has experienced a large outbreak, with over 500 suspected cases, over 200 confirmed cases, and a case fatality ratio of approximately 3%.
Cases continue to be reported until today.
Monkeypox is a disease of global public health importance as it affects countries in west and central Africa and the rest of the world.

The outbreak of the Monkeypox

In 2003, the first Monkeypox outbreak outside Africa was in the United States of America and linked to contact with infected pet prairie dogs.
These pets had housed with Gambian pouched rats and dormice imported into the country from Ghana.
This outbreak led to over 70 cases of Monkeypox in the U.S.
Monkeypox also reported in travellers from Nigeria to Israel in September 2018, to the United Kingdom in September 2018, December 2019, May 2021 and May 2022, Singapore in May 2019, and the United States of America in July and November 2021.
In May 2022, multiple cases of Monkeypox were identified in several non-endemic countries.
Studies are currently underway to further understand the epidemiology, sources of infection, and transmission patterns.

Signs and Symptoms of monkeypox

In humans, the symptoms of Monkeypox are similar to but milder than the symptoms of smallpox.
Monkeypox begins with fever, headache, muscle aches, and exhaustion.
The main difference between symptoms of Smallpox and Monkeypox is that Monkeypox causes lymph nodes to swell (lymphadenopathy) while smallpox does not.
The incubation period (time from infection to symptoms) for Monkeypox is usually 7−14 days but can range from 5−21 days.

The illness begins with:

Fever
Headache
Muscle aches
Backache
Swollen lymph nodes
Chills
Exhaustion

Within 1 to 3 days (sometimes longer) after the appearance of fever, the patient develops a rash, often beginning on the face and then spreading to other parts of the body.

Lesions progress through the following stages before falling off:

Macules
Papules
Vesicles
Pustules
Scabs

The illness typically lasts for 2−4 weeks. In Africa, Monkeypox has been shown to cause death in as many as 1 in 10 persons who contract the disease.

Monkeypox is usually a self-limited disease with symptoms lasting 2 to 4 weeks.

Severe cases occur more commonly among children and are related to the extent of virus exposure, patient health status and complications.

Underlying immune deficiencies may lead to worse outcomes.

Complications of Monkeypox

Although vaccination against smallpox was protective in the past, today, persons younger than 40 to 50 years of age (depending on the country).

Monkeypox may be more susceptible to the cessation of smallpox vaccination campaigns globally after eradicating the disease.

Complications of Monkeypox can include secondary infections, bronchopneumonia, sepsis, encephalitis, and condition of the cornea with ensuing loss of vision.

The extent to which asymptomatic infection may occur is unknown.

The case fatality ratio of Monkeypox has historically ranged from 0 to 11 % in the general population and has been higher among young children.

The case-fatality ratio has been around 3–6% in recent times.

Transmission of Monkeypox

Transmission of the Monkeypox virus occurs when a person comes into contact with the virus from an animal, human, or contaminated material.
The virus enters the body through broken skin (even if not visible), respiratory tract, or mucous membranes (eyes, nose, or mouth).
animal-to-human transmission may occur by bite or scratch, bush meat preparation, direct contact with body fluids or lesion material,
Even indirect contact with lesion material, such as through contaminated bedding.

Human-to-human transmission

Human-to-human transmission is thought to occur primarily through large respiratory droplets.
Respiratory droplets generally cannot travel more than a few feet, so prolonged face-to-face contact is required.
Other human-to-human methods of transmission include direct contact with body fluids or lesion material,
Indirect contact with lesion material, such as contaminated clothing or linens.
The reservoir host (leading disease carrier) of Monkeypox still unknown, although African rodents are suspected of playing a part in transmission.
The virus that causes Monkeypox only recovered (isolated) twice from an animal in nature.
In the first instance (1985), the virus recovered from an ill African rodent (rope squirrel) in the Equateur region of the Democratic Republic of Congo.
In the second (2012), the virus recovered from a dead infant mangabey found in the Tai National Park, Cote d’Ivoire.

Diagnosis of Monkeypox

The clinical differential diagnosis that must consider includes other rash illnesses, such as chickenpox, measles, bacterial skin infections, scabies, syphilis, and medication-associated allergies.
Lymphadenopathy during the prodromal stage of illness can be a clinical feature to distinguish the virus from chickenpox or smallpox.
If Monkeypox suspected, health workers should collect an appropriate sample and transport it safely to a laboratory with proper capability.
Confirmation of Monkeypox depends on the type and quality of the specimen and the type of laboratory test.
Thus, specimens should package and shipped to national and international requirements.
Polymerase chain reaction (PCR) is the preferred laboratory test given its accuracy and sensitivity.
For this, optimal diagnostic samples for monkeypox are from skin lesions – the roof or fluid from vesicles, pustules, and dry crusts.
Where feasible, a biopsy is an option. Lesion samples must stored in a dry, sterile tube (no viral transport media) and kept cold.

PCR Monkeypox blood tests

PCR blood tests are usually inconclusive because of the short duration of viremia relative to the timing of specimen collection after symptoms begin
And should not routinely collected from patients.
As orthopoxviruses serologically cross-reactive, antigen and antibody detection methods do not provide monkeypox-specific confirmation.
Serology and antigen detection methods not recommended for diagnosis or case investigation where resources are limited.
Additionally, recent or remote vaccination with a vaccinia-based vaccine (e.g. anyone vaccinated before smallpox eradication.
More recently vaccinated due to higher risk such as orthopoxvirus laboratory personnel) might lead to false-positive results.

To interpret test results,

patient information must be provided with the specimens, including:

The date of onset of fever,
Also, the date of onset of rash,
furthermore, the date of specimen collection,
current status of the individual (stage of rash),
and e) age.

Therapeutics of Monkeypox

Clinical care for Monkeypox should fully optimised to alleviate symptoms, manage complications and prevent long-term sequelae.
Patients offered fluids and food to maintain good nutritional status.
Secondary bacterial infections should treated as indicated.
An antiviral agent known as tecovirimat that developed for smallpox was licensed by the European Medical Association (EMA)
Monkeypox in 2022 based on data in animal and human studies.
It is not yet widely available.
If used for patient care, tecovirimat should ideally be monitored with prospective data collection in a clinical research context.

Vaccination of Monkeypox

Vaccination against smallpox demonstrated through several observational studies to be about 85% effective in preventing Monkeypox.
Thus, prior smallpox vaccination may result in milder illness.
Evidence of prior vaccination against smallpox can usually found as a scar on the upper arm.
at present, the original (first-generation) smallpox vaccines are no longer available to the general public.
Some laboratory personnel or health workers may have received a more recent smallpox vaccine to protect them from exposure to orthopoxviruses.
A newer vaccine based on a modified attenuated vaccinia virus (Ankara strain) was approved to prevent monkeypox in 2019.
This is a two-dose vaccine for which availability remains limited.
Smallpox and Monkeypox vaccines are developed based on the vaccinia virus due to cross-protection for the immune response to orthopoxviruses.

Prevention of Monkeypox

Raising awareness of risk factors and educating people about the measures they can take to reduce exposure to the virus is the primary prevention strategy for this virus.
Scientific studies are now underway to assess the feasibility and appropriateness of vaccination for the prevention and control of Monkeypox.
Some countries have or are developing policies to offer vaccines to persons at risk, such as laboratory personnel, rapid response teams, and health workers.

1- Reducing the risk of human-to-human transmission

Surveillance and rapid identification of new cases are critical for outbreak containment.
During human virus outbreaks, close contact with infected persons is the most significant risk factor for monkeypox virus infection.
Health workers and household members are at a greater risk of infection.
Health workers caring for patients with suspected or confirmed monkeypox virus infection or handling specimens from them,
It should implement standard infection control precautions.
If possible, persons previously vaccinated against smallpox could selected to care for the patient.

Taken samples

Samples taken from people and animals suspected that virus infection should handled by trained staff in suitably equipped laboratories.
Patient specimens prepared for transport with triple packaging by WHO guidance for the transport of infectious substances.
The identification in May 2022 of clusters of Monkeypox cases in several non-endemic countries with no direct travel links to an endemic area is atypical.
Further investigations are underway to determine the likely infection source and limit further spread.
As the source of this outbreak investigated, it is essential to look at all possible modes of transmission to safeguard public health.

2- Reducing the risk of zoonotic transmission

Over time, most human infections have resulted from direct, animal-to-human transmission.
Unprotected contact with wild animals, especially those sick or dead, including their meat, blood and other parts, must avoid it.
Additionally, all foods containing animal meat or parts must eat it thoroughly cooked.

3- Preventing Monkeypox through restrictions on animal trade

Some countries have put regulations restricting the importation of rodents and non-human primates.
Captive animals potentially infected with monkeypox should isolate from other animals and placed into immediate quarantine.
Any animals that might come into contact with an infected animal should quarantine

How monkeypox relates to smallpox

The clinical presentation of this virus resembles that of Smallpox, a related orthopoxvirus infection which require eradicated.
Smallpox more easily transmitted and more often fatal as about 30% of patients died.
The last case of naturally acquired smallpox occurred in 1977,
In 1980, Smallpox declared eradicated worldwide after a global campaign of vaccination and containment.
It has been 40 or more years since all countries ceased routine smallpox vaccination with vaccinia-based vaccines.
As vaccination is also protected against it in west and central Africa, unvaccinated populations are now more susceptible to monkeypox virus infection.
Whereas smallpox no longer occurs naturally,
The global health sector remains vigilant in the event it could reappear through natural mechanisms, laboratory accidents or deliberate release.
Ensuring global preparedness event reemergence of Smallpox, newer vaccines, diagnostics antiviral agents developed.
These may also now helpful for the prevention and control of monkeypox.

New Outbreak at a glance

Since 13 May 2022, cases of Monkeypox have reported to WHO from 12 Member States that are not endemic to the Monkeypox virus across three WHO regions.
Epidemiological investigations are ongoing, however, reported cases thus far have no established travel links to endemic areas.
As of 21 May, 13:00, 92 laboratory-confirmed cases and 28 suspected Monkeypox cases with ongoing investigations.
The WHO reported that 12 Member States are not endemic to the Monkeypox virus across three WHO regions.
No associated deaths reported to date.
Reported cases thus far have no established travel links to an endemic area.
Based on currently available information, cases have mainly but not exclusively identified amongst men who have sex with men (MSM)
Seeking care in primary care and sexual health clinics.
To date, all cases whose samples confirmed by PCR have identified as infected with West African clade.

sequence of Genome

Genome sequence from a swab sample from a confirmed case in Portugal indicated a close match of the virus causing the current outbreak.
To export cases from Nigeria to the United Kingdom, Israel and Singapore in 2018 and 2019.
The identification of confirmed and suspected cases of these vires with no direct travel links to an endemic area represents a highly unusual event.
Surveillance in non-endemic areas limited but now expanding.
WHO expects cases will report.
Available information suggests that human-to-human transmission occurs among people in close physical contact with symptomatic cases.

Conclusion:

Monkeypox is a rare disease caused by infection with the Monkeypox virus.
Firstly identified in humans in 1970 in the Democratic Republic of the Congo.
Since 13 May 2022, cases of Monkeypox have reported to WHO from 12 Member States that are not endemic to the Monkeypox virus across three WHO regions.
Epidemiological investigations are ongoing, however, reported cases thus far, no established travel links to endemic areas.

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