As the world unwinds from Covid-19, a new scare knocks at our door, monkeypox. Could this viral disease become the next pandemic? Learn more about this disease and its capacity to jump from animals to humans.
By Ricardo Ribas
What is Monkeypox?
Monkeypox is a rare viral infectious disease that affects both animals and humans. The agent, an Orthopoxvirus, is an enveloped double-stranded DNA virus usually endemic in the tropical forests of Central and West Africa and a close relative from the smallpox viruses, a family with a tendency to attack skin cells. Monkeypox is not a recent disease, the virus was first identified in 1958 in laboratory monkeys in Denmark and subsequently in humans in the 1970s in the Republic of the Congo. In contrast to what the name indicates, the natural reservoir of this virus is not the monkey and scientists are still unsure which animal would be, but there are some indications that it might be a rodent. It is known, however, that the monkeypox virus can affect a broad range of animals including rope squirrels, Gambian pouched rats, mice, dormice, non-human primates and humans. There are two known types of monkeypox in humans: one predominantly found in West Africa and responsible for a mild disease (with a fatality rate of about 3-4%) and a second one prominent in Central Africa (Democratic Republic of Congo) and responsible for more severe disease with a fatality rate reaching 10%. Recent studies confirmed that the 2022 outbreak is related to the West African variant and as of the date of this publication, no deaths have been recorded during the current outbreak of the disease.
How is monkeypox transmitted?
The routes of transmission from animals to humans is usually by direct contact with blood, body fluids and the cutaneous lesions (blisters and scabs) as well as by the consumption of uncooked meat or other products from infected animals.
Infection between humans is often a result of sharing clothing, bedding and towels used by someone infected with the virus particularly when suffering from rashes, blisters and scabs. Contamination is also possible through droplets of respiratory particles during coughing or sneezing. Recent research also suggests the possibility for vertical transmission between mother-to-child.
Given the high frequency of human to human transmission observed in the current outbreak of the disease, together with the fact that most of the patients are young adults and middle-aged men who have sex with men, scientists suspect that the close contact during sexual activities might be the main route of transmission. It is, however, important to note, that monkeypox is not a sexually transmitted disease.
So, what are the symptoms?
The incubation period for monkeypox (time between the infection and the appearance of the first symptoms) is between 5 to 21 days. In the first stages, the person will show fever, headache, muscle aches, shivers, swollen gland and tiredness, followed by a rash a few days later. The rash is characterized by the presence of raised spots often starting in the face and later spreading throughout other parts of the body and genitals. The spots eventually turn into small blisters filled with liquid and then into scabs that will fall off within a few weeks. The duration of the symptoms are approximately 2-4 weeks.
Children, immunocompromised individuals and pregnant women are more susceptible to develop severe forms of the disease as well as to suffer complications and a higher fatality rate. Scientists are still not sure why the 2022 outbreak is causing milder symptoms than previously observed, but it may relate to the fact that the virus is infecting a healthier and stronger population (mainly men between 20-50 years of age), from countries with better health care systems than previous outbreaks. There is no evidence that the virus has mutated to become less deadly.
How to treat the disease?
The great majority of people infected will recover from the disease without requiring any specific therapy. However, in severe cases involving immunocompromised patients, pregnant women and children, additional therapy may be required. There is currently no specific treatment approved for monkeypox, but a series of antiviral agents developed for patients suffering from smallpox might be effective. Administration of smallpox vaccines also appear to reduce the severity of the disease and should be consider in the most serious cases.
How to prevent from catching monkeypox?
A series of recommendations are important to keep in mind to prevent infection from monkeypox:
• Avoid direct contact with animals infected with the disease or with any of their derived products, such as blood and uncooked meat,
• Avoid contact with any materials that have been in contact with infected animals or humans,
• Thoroughly cook all foods containing animal meat or their parts before eating,
• Humans infected with monkeypox should isolate until all the symptoms are over and the scabs have fallen off,
• Use protective equipment and practice good hygiene (such as wash the hands with soap and water or hand sanitizer), particularly if in contact with infected animals or humans,
• Professional health workers should implement standard infection control precautions,
• Smallpox vaccines appear to be 85% effective against monkeypox and it can be used as a post-exposure prophylaxis for close contacts of known cases,
• Preferably select people already vaccinated against smallpox to care for animals and patients infected with the disease.
• The governments should improve regulations for animal trade and importation of rodents and non-human primates, such as promotion of isolation and quarantine of animals.
New Outbreak 2022
Monkeypox is generally a mild disease, confined to Central and West Africa, often endemic in Benin, Cameroon, Central African Republic, Democratic Republic of the Congo, Ghana, Ivory Coast, Liberia, Nigeria and Sierra Leone. While it is not the first time that monkeypox spreads to regions outside Africa, this is quite rare. For instance, in 2003, the West African strain managed to reach 70 humans in the United States. This was linked to the direct contact of humans with infected pet prairie dogs who have been housed with Gambian pouched rats imported from Ghana. All 2003 cases resulted from an animal to human contact and there was no evidence of human to human transmission.
The recent 2022 outbreak appears to be the result of the importation of the disease through infected humans with the first case reported in England in an individual recently arrived from Nigeria. As of the day of this publication, more than 1300 cases have been reported throughout Europe, North America, Middle East and Australia, the majority of which as a result of human to human transmission particularly affecting men who have sex with men. Scientists are trying to understand the reason for the spread of the disease outside Africa but are concerned that human monkeypox virus may have already been established as a reservoir in non-African wildlife species creating the perfect environment for future outbreaks and the opportunity for the virus to mutate to more dangerous and transmissible variants.
By Ricardo Ribas, Veterinary Doctor, doctorate in veterinary sciences and scientific researcher.
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The subjects and ideas discussed on this article are for informational purposes only. For more information consult a vet or a professional in the area. Whilst every effort is made to make sure the article is accurate at the time of publication, I take no liability for any new developments on the subject as well as any errors or omissions.