With the WHO declaring monkeypox a global public health emergency of international concern and India reporting four cases of the disease, experts on Sunday said there is no need to panic as it is less contagious and rarely fatal.

According to these experts, a monkeypox outbreak can effectively be tackled by strong surveillance. The virus spread can be contained by isolation of confirmed cases and quarantine of contacts, they said, and underlined that immunocompromised individuals need to take care.

Senior scientist at Pune's National Institute of Virology (NIV) Dr Pragya Yadav said monkeypox virus is an enveloped double-stranded DNA virus having two distinct genetic clades -- the central African (Congo Basin) clade and the west African clade.

"The recent outbreak which has affected several countries leading to a worrisome situation is caused by the west African strain which is less severe than the Congo lineage reported earlier. The cases reported in India are also of the less severe west African lineage," she told PTI.

The NIV is one of the major institutes of the Indian Council of Medical Research.

Epidemiologist and infectious diseases physician Dr Chandrakant Lahariya said monkeypox is not a new virus. It has been present globally for five decades, and there is a reasonable understanding of its viral structure, transmission and pathogenicity, he added.

"The virus causes mostly mild illness. It is less contagious and requires close personal contact with symptomatic individuals in contrast to the SARS-CoV-2 that had a respiratory spread and a high proportion of asymptomatic cases.

"There is every reason, as of now, to believe that a monkeypox outbreak can effectively be tackled and the virus contained by isolation of confirmed cases, quarantine of contacts and the use of authorised smallpox vaccines as 'off-label' for 'ring vaccination," Lahariya said, adding that vaccination for the general population is not currently recommended.

The World Health Organisation (WHO) on Saturday declared monkeypox a global public health emergency of international concern and called on nations to work closely with communities of men who have sex with men and adopt measures that protect the health, human rights and dignity of affected communities.

More than 16,000 cases of the disease have now been reported from 75 countries and there have been five deaths so far as a result of the outbreak.

Chief of Covid Working Group of NTAGI Dr N K Arora said there is no need to panic because the disease is less infectious and rarely fatal. But individuals with immunocompromised states need to be particularly careful, he said.

"Even though its spread is a matter of concern, there is no need to panic. The virus can be contained by strong surveillance, isolation of confirmed cases, contact-tracing," he told PTI.

Based on the lessons learnt from the COVID-19 pandemic, India has put in a surveillance system for detection and tracking of monkeypox cases in the country.

India has so far reported four cases of the disease three in Kerala and one in Delhi. The Centre on Sunday held a high-level review meeting after a 34-year-old man from the national capital with no history of foreign travel tested positive for the monkeypox virus.

The Union Health Ministry had last week reviewed the functioning of health screening of international travellers arriving in India at airports and ports.

Airport and port health officers (APHOs and PHOs) and directors from regional offices of Health and Family Welfare who attended the meeting were advised to ensure strict health screening of all arriving international travellers to minimise the risk of importation of monkeypox cases into the country, a health ministry statement had said.

According to WHO, monkeypox is a viral zoonosis (a virus transmitted to humans from animals) with symptoms similar to those seen in the past in smallpox patients, although it is clinically less severe.

Monkeypox typically presents with fever, rash and swollen lymph nodes and may lead to a range of medical complications.

It is usually a self-limited disease with the symptoms lasting from two to four weeks.

In the 'Guidelines on Management of Monkeypox Disease' issued to states and Union territories, the Centre has stated that human-to-human transmission occurs primarily through large respiratory droplets generally requiring a prolonged close contact.

It can also be transmitted through direct contact with body fluids or lesion material, and indirect contact with lesion material, such as through contaminated clothing or linens of an infected person.

Animal-to-human transmission may occur by bite or scratch of infected animals like small mammals, including rodents (rats, squirrels), and non-human primates (monkeys, apes) or through bush meat preparation.

The incubation period (interval from infection to onset of symptoms) of monkeypox is usually from six to 13 days but can range from five to 21 days, the document stated.

The case fatality ratio of monkeypox has historically ranged from zero to 11 per cent in the general population and has been higher among young children. In recent times, the case fatality ratio has been around three-six per cent, it said.

Its symptoms include lesions, which usually begin within one-three days of fever onset, lasting for around two-four weeks and are often described as painful until the healing phase when they become itchy (in the crust stage).