Monkeypox is the latest disease to hit the headlines in a troubling trend for emerging diseases.

The monkeypox virus (MPXV) was identified in a laboratory in 1958, and monkeypox as a disease in humans in 1970.

The current outbreak was declared a Public Health Emergency of International Concern by the World Health Organization in July 2022. On September 1, 2022 there were 52,090 confirmed cases globally, of which less than 500 are in areas where monkeypox historically has occurred. 

What is MPXV?

MPXV is a member of the Poxviridae family, under the Orthopox genus. It is an enveloped, double-stranded DNA virus with a diameter of 200 to 250 nm. There are two clades (groups) within MPXV: Clade 1 (previously

known as the Congo Basin Clade) and Clade 11 (previously known as the West African Clade). Clade 1 is considered a high-consequence infectious disease in the UK. Clade 11 is less virulent. For Clade 1 the RO is between 0.6 and 1.0 and believed to be lower for Clade 11. The current monkeypox outbreak is caused by Clade 11b.

Modes of Transmission

MPXV is transmitted primarily through direct contact. It can also be transmitted through indirect contact, respiratory secretions, and as a zoonotic disease. Direct human-to-human transmission is the most common mode of transmission, involving close (often intimate) contact with the source individual’s rash, scabbed pustules or body fluids (including blood).

·        Transplacental transmission from mother to foetus is possible, as well as from pregnant women to babies during birth. Potential transmission by faecal transplants has been reported, as MPXV has been found in stool samples and rectal swabs. 

·        Respiratory secretions in exhaled large droplets can spread MPXV at short distance from the source individual. It is believed that MPXV does not linger in the air.  Aerosolized transmission has not been reported. However, aerosolized transmission in experimental studies in monkeys has occurred. In the UK, MPXV is included under airborne transmission. 

Signs and Symptoms

·       Signs and symptoms include a rash, malaise, fever, chills, lymphadenopathy, headaches, and myalgia. An estimated 98.6% of individuals with

·       Most of the signs and symptoms are common to smallpox and to chickenpox. Lymphadenopathy is a key feature for monkeypox and does not occur with chickenpox or smallpox.

Oral and Oropharyngeal Manifestations

An estimated 70% of individuals with monkeypox are reported to experience intraoral lesions.  Oral lesions can present as ulcerations or erythematous areas, on any area of oral mucosa. Skin lesions develops later.  Perioral lesions may also be present. In some cases, lesions have a similar appearance to herpes lesions (cold sores), trauma or hand, foot and mouth disease. 

Testing and Treatment

Non-variola orthopox/MPXV testing is available and recommended for individuals with a rash or lesions consistent with monkeypox.  Polymerase chain reaction testing is performed for confirmation. Antiviral agents, including TPOXX, can be used to treat patients with monkeypox, under an Expanded Access Investigational New Drug (EA-IND) protocol.

Vaccines against monkeypox

The vaccine JYNNEOS is FDA-approved against monkeypox (and smallpox) in individuals 18 years-of-age and older and administered as two subcutaneous injections 28 days apart. Peak immunity is attained 14 days after the second dose. The vaccine is contraindicated during pregnancy and while breastfeeding. It is also in short supply and is now being used in the US at a 20% dose and given intradermally. The alternative is the ACAM2000 vaccine, which is effective against smallpox.

Considerations for pets and animals

It has been advised that ‘veterinarians should consider all mammals susceptible to monkeypox’. It is also advised to individuals with monkeypox to avoid contact with pets, domestic animals, and wildlife to prevent transmission.

Conclusions

Transmission during the current outbreak is largely by direct contact and infectivity is relatively low. Identification, tracing, and isolation are important in combatting transmission.

 Dental professionals are uniquely qualified to identify oral and peri-oral lesions, as well as oropharyngeal lesions. Early identification of potential cases together with earlier isolation for suspected and confirmed cases lead to reduced opportunity for further transmission.