While clinically less severe than smallpox, monkeypox is a viral zoonosis (a virus that spreads from animals to people). It has symptoms that are comparable to those of smallpox. Monkeypox has replaced smallpox as the most significant orthopoxvirus for public health since smallpox was eradicated in 1980 and smallpox vaccinations were subsequently discontinued. Primarily affecting central and west Africa, monkeypox has been spreading into cities and is frequently seen close to tropical rainforests. Numerous rodent species and non-human primates serve as hosts for animals.
A double-stranded DNA pathogen with an envelope, the monkeypox virus is a member of the Poxviridae family and belongs to the genus Orthopoxvirus. The central African (Congo Basin) clade and the west African clade are two separate genetic clades of the monkeypox virus. In the past, the Congo Basin clade was thought to be more contagious and to produce more severe illness. The only nation where both viral clades have been discovered is Cameroon, which serves as the geographic boundary between the two groups.
The monkeypox virus’s natural host
The monkeypox virus has been found to be susceptible to several animal species. This comprises non-human primates, dormice, rope and tree squirrels, Gambian pouched rats, and other species. There is still uncertainty about the monkeypox virus’s natural history, and further research is required to pinpoint the precise reservoir or reservoirs and understand how the virus circulates in the wild.
In the Democratic Republic of the Congo, where smallpox had been eradicated in 1968, a 9-month-old boy was the first person to be diagnosed with human monkeypox. Since then, human cases have progressively been recorded from central and west Africa, with the majority of cases coming from the rural, rain forest parts of the Congo Basin, mainly in the Democratic Republic of the Congo.
Benin, Cameroon, 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 are the 11 African nations where human cases of monkeypox have been documented since 1970. Unknown is the true cost of monkeypox. For instance, an epidemic with a lower case fatality ratio and a higher attack rate than typical was reported in the Democratic Republic of the Congo in 1996–1997. Monkeypox and chickenpox outbreaks that occurred simultaneously in this instance could be explained by real or apparent modifications in the dynamics of transmission produced by the varicella virus, which is not an orthopoxvirus. Over 500 suspected cases, over 200 confirmed cases, and a case fatality rate of about 3 percent have been reported in Nigeria since 2017. Cases are still being reported today.
Given that it affects the rest of the world in addition to countries in west and central Africa, monkeypox is a disease of worldwide public health significance. The first monkeypox outbreak outside of Africa occurred in the United States of America in 2003, and contact with pet prairie dogs that had the disease was to blame. These pets had been kept with dormice and pouched rats from Ghana that were imported from the Gambia. Over 70 cases of monkeypox were brought on by this outbreak in the US.
Travelers from Nigeria to Israel in September 2018, the UK 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 have also been reported to have monkeypox. Monkeypox cases were found in a number of non-endemic nations in May 2022. Studies are being conducted right now to learn more about the epidemiology, sources of illness, and patterns of transmission.
Transmission Direct contact with the blood, body fluids, cutaneous or mucosal lesions of infected animals can result in animal-to-human (zoonotic) transmission. Numerous animals in Africa, including rope squirrels, tree squirrels, Gambian pouched rats, dormice, various species of monkeys, and others, have shown signs of monkeypox virus infection. Rodents are the most plausible candidates for the monkeypox natural reservoir, though this has not yet been determined. Eating undercooked meat and other diseased animal products is a potential risk factor. People who live in or close to forests may be indirectly or minimally exposed to diseased animals.
Close contact with respiratory secretions, skin sores on an infected person, or recently contaminated objects can cause human-to-human transmission. Health professionals, family members, and other close contacts of current patients are more at risk because droplet respiratory particles typically require extended face-to-face contact. The number of person-to-person infections in a community’s longest documented chain of transmission has increased from 6 to 9 in recent years.
This might be an indication of a general decline in immunity brought on by the end of smallpox vaccination campaigns. Congenital monkeypox can result through transmission through the placenta, which can also happen during intimate contact during labour and after delivery. Although close physical contact is a known risk factor for transmission, it is not known at this time whether monkeypox can particularly spread through sexual intercourse. Studies are required to comprehend this risk better.
Symptoms and signs
Monkeypox typically takes 6 to 13 days to incubate, although it can take anything from 5 to 21 days for symptoms to appear. There are two phases to the infection: the 0–5-day invasion period is marked by fever, severe headache, lymphadenopathy (swelling of the lymph nodes), back pain, myalgia (muscle aches), and severe asthenia (lack of energy). Compared to other diseases that may initially seem similar, monkeypox has a specific characteristic called lymphadenopathy (chickenpox, measles, smallpox)