MPXV is generally self-limiting in nature. The symptoms resolve within 14–21 days after the appearance of initial symptoms. Currently, two types of MPXV are found: the Western and Central-African strains. The mortality rate of the West-African type is around 3.6%, but sometimes it may cause severe illness. In contrast, the Central-African type has a high mortality of approximately 10.6%. The epidemiological study of MPXV can be divided into two parts, endemic regions, and non-endemic regions. The endemic area includes the Democratic Republic of the Congo, Nigeria, Cameroon, the Central African Republic, and the Republic of the Congo (Ladnyj et al. 1972; Cho and Wenner 1973). The non-endemic areas include Europe, America, and Asia, which reported recent cases. The first outbreak of MPXV in a non-endemic region was reported in 2003 in the US due to some infected rodents and prairie dogs imported from Ghana (Cho and Wenner 1973).
The incidence of human monkeypox was sporadically reported from 1970 till 2017. However, the number of cases increased rapidly, with 2,828 suspected cases and 69 mortalities in 5 endemic countries. In 2020, 6368 suspected cases were reported, with 231 mortalities in 7 countries. However, in 2021, more cases reduced by 49% than in 2020 (Bunge et al. 2022). The leading cause of the upsurge is still unknown, but deforestation, contact of humans with wild animals, and bushmeat consumption could be one of the major causes. 23,428 cumulative suspected cases with 589 mortalities have been reported from the endemic region since 2017 (Chakraborty et al. 2022). The fatality rate was around 2.5%. The Democratic Republic of the Congo includes approximately 96% of the cases in the endemic belt. Fatalities have been higher in young patients and HIV-infected individuals (Chakraborty et al. 2022; Oprea et al. 2022).
Table 1
Table showing cumulative cases and deaths due to human monkeypox in the endemic regions from 1st January 2022 to 12th October 2022 (https://www.afro.who.int/health-topics/disease-outbreaks/outbreaks-and-other-emergencies-updates).
Sl. No. | Country | Confirmed cases (Cumulative) | Suspected cases | Confirmed deaths (Cumulative) |
1 | Nigeria | 400 | 110 | 7 |
2 | Democratic Republic of the Congo | 200 | 1356 | 64 |
3 | Ghana | 103 | 12 | 4 |
4 | Central African Republic | 10 | 17 | 2 |
5 | Cameroon | 8 | 28 | 2 |
6 | Republic of Congo | 2 | 7 | 3 |
7 | Liberia | 2 | 4 | 0 |
8 | Sierra Leone | 0 | 2 | 0 |
| Total | 725 | 1536 | 82 |
The first MPXV infection in 2022 outside the endemic region was reported in the United Kingdom from a patient with a travel history from Nigeria. The case was confirmed on 7th May 2022 and immediately isolated. Six more confirmed cases were reported between 13th – 15th May 2022 (https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON383). Two belonged to the same family as the case reported on 7th May. Most of the samples tested positive for the Western-African strain (Kugelman et al. 2014). At the end of May, 190 confirmed cases were recorded in the UK. The government of the UK gave particular emphasis on sexual contact, especially for patients who showed blisters within three weeks of sexual contact. On 7th June 2022, they declared MPX as a "Notifiable Disease" and emphasized diagnosis and contact tracing. The number of cases crossed a thousand by the end of June. Till 15th August 2022, a total of 3,201 confirmed cases were recorded (https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON383).
Apart from the UK, confirmed cases were reported from other European nations and non-European nations such as Argentina, Canada, French Guiana, United States of America, United Arab Emirates, Sudan, Belgium, Austria, Czechia, Denmark, France, Finland, Germany, Israel, Italy, Netherlands, Slovenia, Portugal, Spain, Switzerland, Sweden, Northern Ireland, United Kingdom of Great Britain, Australia, Benin, Poland, Latvia, Serbia, Luxemburg, and India (Oprea et al. 2022) (https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON383). Cases began to increase from May 2022 among individuals with a travel history from the endemic African countries and the UK. The Centers for Disease Control and Prevention (CDC) emphasizes contact tracing and diagnosis of infected individuals in both US and other countries. The CDC has guidelines for vaccination strategies, including post-exposure and pre-exposure prophylaxis. These vaccines include ACAM2000 and JYNNEOS, which are smallpox vaccines discussed in the later sections of this article (https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON396). India also reported a total number of 10 cases by 29th August 2022. The Ministry of Health and Family Welfare, Government of India, published the protocol for healthcare professionals and patients on 31st May 2022. However, the most alarming aspect is that the 4th confirmed case was reported from West Delhi, who had no travel history to any country (https://timesofindia.indiatimes.com/india/indias-4th-monkeypox-case-in-delhi-patient-has-no-foreign-travel history/articleshow/93096145.cms).
Table 2
Table showing total confirmed cases of human monkeypox in the non-endemic regions till 12th October 2022 (Mathieu et al. 2015).
Sl. No. | Country | Confirmed cases (Cumulative) | Confirmed deaths (Cumulative) |
1 | United States | 26393 | 2 |
2 | Brazil | 8270 | 3 |
3 | Spain | 7219 | 2 |
4 | France | 4043 | 0 |
5 | United Kingdom | 3654 | 0 |
6 | Germany | 3645 | 0 |
7 | Peru | 2587 | 2 |
8 | Colombia | 2453 | 0 |
9 | Mexico | 1968 | 1 |
10 | Canada | 1411 | 0 |
11 | Netherlands | 1221 | 0 |
12 | Chile | 977 | 0 |
13 | Portugal | 930 | 0 |
14 | Italy | 854 | 0 |
15 | Belgium | 775 | 1 |
16 | Switzerland | 517 | 0 |
17 | Argentina | 479 | 0 |
18 | Austria | 317 | 0 |
19 | Israel | 254 | 0 |
20 | Bolivia | 215 | 0 |
21 | Sweden | 198 | 0 |
22 | Ireland | 198 | 0 |
23 | Poland | 195 | 0 |
24 | Puerto Rico | 188 | 0 |
25 | Denmark | 187 | 0 |
26 | Ecuador | 142 | 1 |
27 | Australia | 138 | 0 |
28 | Norway | 92 | 0 |
29 | Greece | 82 | 0 |
30 | Hungary | 78 | 0 |
31 | Czechia | 72 | 1 |
32 | Luxembourg | 55 | 0 |
33 | Dominican Republic | 52 | 0 |
34 | Slovenia | 47 | 0 |
35 | Finland | 41 | 0 |
36 | Romania | 40 | 0 |
37 | Serbia | 40 | 0 |
38 | Guatemala | 38 | 0 |
39 | Malta | 33 | 0 |
40 | Croatia | 29 | 0 |
41 | Singapore | 19 | 0 |
42 | Sudan | 17 | 1 |
43 | United Arab Emirates | 16 | 0 |
44 | Panama | 16 | 0 |
45 | Iceland | 16 | 0 |
46 | Slovakia | 14 | 0 |
47 | Jamaica | 14 | 0 |
48 | India | 12 | 1 |
49 | Turkey | 12 | 0 |
50 | Estonia | 11 | 0 |
51 | Lebanon | 11 | 0 |
52 | New Zealand | 11 | 0 |
53 | Thailand | 10 | 0 |
54 | Uruguay | 9 | 0 |
55 | El Salvador | 9 | 0 |
56 | Saudi Arabia | 8 | 0 |
57 | Venezuela | 8 | 0 |
58 | Japan | 7 | 0 |
59 | Bulgaria | 6 | 0 |
60 | Latvia | 6 | 0 |
61 | Costa Rica | 6 | 0 |
62 | Honduras | 6 | 0 |
63 | Bosnia and Herzegovina | 6 | 0 |
64 | Lithuania | 5 | 0 |
65 | South Africa | 5 | 0 |
66 | Cyprus | 5 | 0 |
67 | Qatar | 5 | 0 |
68 | Ukraine | 5 | 0 |
69 | China | 5 | 0 |
70 | Andorra | 4 | 0 |
71 | Philippines | 4 | 0 |
72 | Cuba | 4 | 1 |
73 | Benin | 3 | 0 |
74 | Taiwan | 3 | 0 |
75 | Monaco | 3 | 0 |
76 | Morocco | 3 | 0 |
77 | Greenland | 2 | 0 |
78 | Georgia | 2 | 0 |
79 | Moldova | 2 | 0 |
80 | Montenegro | 2 | 0 |
81 | Bahamas | 2 | 0 |
82 | Russia | 2 | 0 |
83 | South Korea | 2 | 0 |
84 | Guyana | 2 | 0 |
85 | Barbados | 1 | 0 |
86 | Martinique | 1 | 0 |
87 | Bermuda | 1 | 0 |
88 | New Caledonia | 1 | 0 |
89 | Indonesia | 1 | 0 |
90 | Iran | 1 | 0 |
91 | Bahrain | 1 | 0 |
92 | Egypt | 1 | 0 |
93 | Hong Kong | 1 | 0 |
94 | Jordan | 1 | 0 |
95 | Paraguay | 1 | 0 |
| Total | 70458 | 16 |