Monkeypox virus causes a disease with symptoms similar to smallpox

Amid the scare and increasing number of Covid-19 cases in the world, a rare case of Monkeypox virus has been recently confirmed in a patient travelling to Nigeria. In relation to this the CDC, which is a Health Protection Agency at the US said that this virus has shown to cause death to 1 in 10 persons.

Monkeypox is a rare disease, caused by infection with 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.

The virus is a double-stranded DNA, zoonotic virus and a species of the genus Orthopoxvirus in the family Poxviridae. It is one of the human orthopoxviruses that includes variola, cowpox, and vaccinia viruses.

According to WHO, Monkeypox is an orthopoxvirus that causes a disease with symptoms similar , but less severe , to small pox.  

Transmission of the virus can occur when a person comes in contact with the fomite or get exposed to the virus/germ via exhaled large droplets. The virus then enters the body through the broken skin (even if not visible), respiratory tract, or the 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, or indirect contact with lesion material, such as through contaminated bedding.

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, and indirect contact with lesion material, such as through contaminated clothing or linens.

The symptoms of monkeypox are similar to but milder than the symptoms of the small pox. The main difference is that monkeypox causes lymph nodes to swell while small pox does not. The symptoms include fever, headache, muscle aches, pain in backbone, swelling up of lymph nodes and exhaustion.

In this context, WHO adds that the infection in humans can be fatal even though this disease is often self-limiting and the signs and symptoms generally resolve spontaneously within 3-4 weeks.

The main difference is that monkeypox causes lymph nodes to swell while small pox does not. The symptoms include fever, headache, muscle aches, pain in backbone, swelling up of lymph nodes and exhaustion.

The reservoir host (main disease carrier) of monkeypox is still unknown although African rodents are suspected to play a part in transmission.

Monkeypox is a zoonosis: a disease that is transmitted from animals to humans. Cases are often found close to tropical rainforests where there are animals that carry the virus. Evidence of monkeypox virus infection has been found in animals including squirrels, Gambian poached rats, dormice, different species of monkeys and others.

Human-to-human transmission is limited, with the longest documented chain of transmission being six generations, meaning that the last person to be infected in this chain was six links away from the original sick person. It can be transmitted through contact with bodily fluids, lesions on the skin or on internal mucosal surfaces, such as in the mouth or throat, respiratory droplets and contaminated objects.

Detection of viral DNA by polymerase chain reaction (PCR) is the preferred laboratory test for monkeypox. The best diagnostic specimens are directly from the rash " skin, fluid or crusts, or biopsy where feasible. Antigen and antibody detection methods may not be useful as they do not distinguish between orthopoxviruses. No vaccine has come up which will be giving protection against this virus. For purposes of controlling a monkeypox outbreak in the United States, smallpox vaccine, antivirals, and vaccinia immune globulin (VIG) can be used.

"It is important to emphasise that monkeypox does not spread easily between people and the overall risk to the general public is very low," Dr. Colin Brown, Director of Clinical and Emerging Infections at the UKHSA, said on Saturday.

"We are working with NHS England and NHS Improvement (NHSEI) to contact the individuals who have had close contact with the case prior to confirmation of their infection, to assess them as necessary and provide advice. UKHSA and the NHS have well established and robust infection control procedures for dealing with cases of imported infectious disease and these will be strictly followed," he said.

The patient is being treated in a specialist isolation unit at St. Thomas Hospital by expert clinical staff with strict infection prevention procedures, added Dr. Nicholas Price, Consultant in Infectious Diseases at Guy's and St. Thomas' Hospital.

As a precautionary measure, UKHSA experts said they are working closely with England's state-funded National Health Service (NHS) and will be contacting people who might have been in close contact with the individual to provide information and health advice.