Epidemiology

Monkeypox is a viral zoonosis disease caused by monkeypox virus. Like cowpox virus and variola virus (which causes smallpox), the monkeypox virus is a species of the genus Orthopoxvirus in the family Poxviridae. Clinically, monkeypox has similar symptoms as like Smallpox but smallpox is more contagious and fatal in nature.

The classical feature which differentiate monkeypox with smallpox, chickenpox and measles is swelling of lymph nodes. Monkey pox was considered as a disease of non-primates and rodents before 1970 before the first case of monkey pox in human was identified in the Democratic Republic of Congo.

While smallpox was eradicated in 1980, monkeypox continues to occur as an endemic to about 12 Western and Central African nations, frequently near tropical rainforests, and outbreaks in other nations were uncommon. Monkeypox endemic countries of this region includes: Benin, Cameroon, the Central African Republic, the Democratic Republic of the Congo, Gabon, Ghana (identified in animals only), Ivory Coast, Liberia, Nigeria, the Republic of the Congo, Sierra Leone, and South Sudan. In 2003, the first monkey pox outbreak outside of Africa was in the United States of America and was linked to contact with infected pet prairie dogs who were housed with Gambian pouched rats and dormice that had been imported to USA from Ghana. This outbreak led to over 70 cases of monkeypox in the U.S. Monkey pox has also been reported in travelers from Nigeria to Israel in September 2018, to the United Kingdom in September 2018, December 2019, May 2021 and May 2022, to Singapore in May 2019, and to the United States of America in July and November 2021. In May 2022, multiple cases of monkey pox were identified in several non-endemic countries. Even one case of monkey pox in a non-endemic country is considered an outbreak.

The monkeypox virus has two distinct genetic clades:

1. Clade I: Formerly known as Central African clade, is a subtype prevalent in the Central African Republic and the Democratic Republic of the Congo. The  virus of this subtype causes more severe illness and the case fatality rate is 11%.

2. Clade II:  Formerly known as The West African clade is a subtype prevalent in Nigeria, Côte d’Ivoire, Liberia and Sierra Leone This subtype is has relatively less human to-human transmission with less severe illness, and the case fatality rate is 6%. All cases whose samples were confirmed by PCR till date have been identified as being infected with the West African clade.

Transmission of monkeypox to humans occurs mainly through contact with body fluids, skin lesions, or respiratory droplets from infected animals directly or indirectly through contaminated fomites. The extent of viral circulation in animal populations and the range of species that may harbour the virus has not been fully established, although several lines of evidence point to rodents as major potential reservoirs. However, the primary reservoir for human infection remains unknown. Human-to-human transmission results from close contact with infected respiratory droplets, skin lesions, or contaminated objects.  Health care workers and household members of active cases are at higher risk of infection. 

As human-to-human transmission is limited, most outbreaks consist of only a few cases within families. The interval from infection to onset of symptoms is usually 6 to 13 days, but can range from 5 to 21 days. The infection progresses in two phases:  the invasion period (0-5 days) characterized by fever, headache, lymphadenopathy (swelling of the lymph nodes), back pain, myalgia (muscle aches), and fatigue; and A characteristic rash appearing in stages 1-3 days after the onset of fever, beginning on the face and spreading to the trunk and limbs. The rash lesions evolve from macules (lesions with a flat base) to papules (raised firm lesions) to vesicles (filled with clear fluid) to pustules (filled with yellowish fluid), followed by crusts  The rash affects the face in 95% of cases,  the palms and soles of the feet (75%), oral mucous membranes (70%),  genitalia (30%), the conjunctivae and cornea (20%). It may take three weeks for crusts to disappear. Lesions range from a few to several thousand and are painful in nature. Severe lymphadenopathy (swollen lymph nodes) is a distinctive feature of monkey pox and generally develops before the rash.

Is Nepal at Risk?

Nepal is at the risk of outbreak of monkey pox as a disease outbreak to any country is a disease threat to every country across the globe. Ever since a case of monkey pox was reported in UAE most of the south Asian countries including Nepal remains at the high risk of outbreak as large number of migrant workers from this region work in UAE and have frequent to and froth movement to their country of origin. In 14 July 2022, India became the first country from South Asia to report the case of monkey pox. It was confirmed that the patient had a travel history from UAE and had a close contact with a person contracting monkey pox back in UAE. India reported the first case of monkey pox induced death on 31 July, 2022 in Kerala state. The patient also had the history of travel from UAE and was in close contact with the positive case of monkey back in UAE.

Nepal reported a suspected case of monkeypox on 16 July, 2022. The suspect was returning from UAE and exhibited the symptoms of monkeypox like fever and rashes all over the body. He was referred to the Sukraraj Tropical and Infectious Disease Hospital for further treatment and isolation. Large number of migrant workers traveling from UAE, country’s dependence on tourism sector leading to frequent movement of people from abroad and open border with India poses Nepal to the risk of disease outbreak.

Monkey pox is an emerging disease with potential for outbreak both in humans, animals and rodents. So, Nepal must work to various health education measures focusing on risk of handling or consuming wild animals and close contact with them, maintenance of slaughter hygiene and isolation of patients to avoid close contact during monkey pox outbreaks should be focused.

Monkeypox must be integrated to disease surveillance and reporting system to detect the suspected case and respond immediately for proper outbreak management. Crisis communication during health emergencies must be strengthened to combat stigma and discrimination which are likely to occur in monkey pox as it is reported to be transmitted via sexual intercourse and the disease is more prevalent in gay men. Such stigma may lead to a situation where suspected patients may not seek healthcare and diagnosis. Health education and awareness programs must be given to communities of men who have sex with men and LGBTIQ community.

Nepal has been adopting one health initiative to tackle the problem of rabies which focus on outbreak management of rabies in humans and dogs and other highly pathogenic avian influenza. Presence of monkeys in temples and parks which are the major touristic destinations of Kathmandu might contribute to the outbreak of monkey pox in Nepal. Zoonosis like monkeypox requires a collaborative efforts from multiple stakeholders.

There must be good coordination between different government and non-government sectors to obtain optimal health for people, animals and environment to tackle zoonotic diseases having outbreak potential. The global community must prioritize stronger global surveillance and international collaboration for rapid case detection to combat the viral infection and hinder the spread of the disease.

 

References

1.         Monkeypox: Epidemiology, preparedness and response for African Available from: https://openwho.org/courses/monkeypox-intermediate

2.         Subedi D, Acharya KP. Risk of monkeypox outbreak in Nepal. Travel Med Infect Dis. 2022 Jun 9;49:102381.