From UPSC perspective, the following things are important :
Prelims level : Monkey Pox
Mains level : Rise in zoonotic diseases
With cases being reported from across the world, monkeypox has caught everyone’s attention.
What is Monkeypox?
- Monkeypox is not a new virus.
- The virus, belonging to the poxvirus family of viruses, was first identified in monkeys way back in 1958, and therefore the name.
- The first human case was described in 1970 from the Democratic Republic of Congo.
- Many sporadic outbreaks of animal to human as well as human to human transmission has occurred in Central and West Africa in the past with significant mortality.
- After the elimination of smallpox, monkeypox has become one of the dominant poxviruses in humans, with cases increasing over years along with a consequent reduction in the age-group affected.
How is it transmitted?
- Since the transmission occurs only with close contact, the outbreaks have been in many cases self-limiting.
- Since in the majority of affected people, the incubation period ranges from five to 21 days and is often mild or self-limiting, asymptomatic cases could transmit the disease unknowingly.
- The outbreaks in Central Africa are thought to have been contributed by close contact with animals in regions adjoining forests.
- While monkeys are possibly only incidental hosts, the reservoir is not known.
- It is believed that rodents and non-human primates could be potential reservoirs.
Does the virus mutate?
- Monkeypox virus is a DNA virus with a quite large genome of around 2,00,000 nucleotide bases.
- While being a DNA virus, the rate of mutations in the monkeypox virus is significantly lower (~1-2 mutations per year) compared to RNA viruses like SARS-CoV-2.
- The low rate of mutation therefore limits the wide application of genomic surveillance in providing detailed clues to the networks of transmission for monkeypox.
- A number of genome sequences in recent years from Africa and across the world suggest that there are two distinct clades of the virus — the Congo Basin/Central African clade and the West African clade.
- Each of the clades further have many lineages.
What do the genomes say?
- With over a dozen genome sequences of monkeypox, it is reassuring that the sequences are quite identical to each other suggesting that only a few introductions resulted in the present spread of cases.
- Additionally, almost all genomes have come from the West African clade, which has much lesser fatality compared to the Central African one.
- This also roughly corroborates with the epidemiological understanding that major congregations in the recent past contributed to the widespread transmission across different countries.
Does it have an effective vaccine?
- It is reassuring that we know quite a lot more about the virus and its transmission patterns.
- We also have effective ways of preventing the spread, including a vaccine.
- Smallpox/vaccinia vaccine provides protection.
- While the vaccine has been discontinued in 1980 following the eradication of smallpox, emergency stockpiles of the vaccines are maintained by many countries.
- Younger individuals are unlikely to have received the vaccine and are therefore potentially susceptible to monkeypox which could partly explain its emergence in younger individuals.