Monkeypox virus: A spreading threat for Pakistan?

1. Main text

With over 200 cases detected worldwide in the past month, the recent Monkeypox viral outbreak has sparked a global concern since its re-emergence in May 2022. [1] The rare contagion, belonging to the orthopoxvirus family was initially identified as a familial cluster of two cases in the United Kingdom on the 13th of May. [2] Since then, sporadic outbreaks have been reported in 20 countries around the globe, including England, Spain, Portugal, Germany, Netherlands, Canada, Italy, Belgium, France, United States, and Australia. [1, 3].

First discovered in 1958 amongst research monkeys, Monkeypox disease, caused by the Monkeypox virus (MPXV) is a sylvatic zoonosis closely related to the Variola virus (smallpox virus). [4] The first human case was recorded in 1970 in the Democratic Republic of Congo (DRC). [5] Since then, the virus has spread substantially due to the rapid surge in human urbanization of virus reservoirs and environmental deterioration; [6] eight Monkeypox viral outbreaks have been recorded thus far in countries including, DRC, Nigeria, and United States. [[7], [8]] Furthermore, the disease is considered an endemic in several parts of Western and Central Africa, [9] where a few thousand cases are recorded each year. [10] However, the recent surge in Monkeypox cases in non-endemic countries is alarming; thus compelling us to evaluate the potential threat posed by the contagion to developing countries, particularly Pakistan.

Monkeypox typically transmits to humans from wild animals, such as rodents and primates (animals-to-humans), or in some cases, from other infected individuals (humans-to-humans). [[5], [8]] The opportunistic infection predominantly spreads through contact, such as hunting or consuming disease-ridden animals. [2] It can also spread through large aerosol droplets or contact with body fluids (saliva and blood), infected skin lesions, or contaminated materials, such as the clothing of an infected individual. [5] Following an incubation period of 5–21 days, the virus clinically manifests as fever, headache, myalgia, lymphadenopathy, and fatigue, similar to the presentation of the smallpox infection. [5] Individuals infected with a more barbaric form of the disease may also develop a characteristic ‘Monkeypox rash’, starting from their face and hands and later spreading to other body parts. The lesions which typically start as macules progress into papules, followed by fluid-filled vesicles, pus-filled pustules, and subsequently, scabs that crust and eventually fall off. [5] The disease is often self-limiting, with the symptoms eventually resolving within 2–4 weeks. [5] As supported by historical data, the smallpox vaccine (Imvanex) is 85% effective against Monkeypox. [11] Similarly, antivirals, including Tecovirimat, Cidofovir, and Vaccinia Immune Globulin Intravenous (VIGIV) approved for smallpox infection, can also be used for Monkeypox treatment. [5]

Due to the atypical disease presentation and transmission patterns, the recent MPXV surge is “rare and unusual” [12] compared to earlier outbreaks. As reported by health experts, most of the Monkeypox cases recorded in the past month in the Western Hemisphere have no known epidemiological links to endemic countries. Additionally, most of the cases were documented among young men engaging in homosexual or bisexual activities, commonly known as “men who have sex with men” (MSM). [2] Most of these cases presented with genital or peri-genital lesions, indicating a new route of disease spread: sexual contact. [13] Although a definite cause for the sudden upsurge in cases is yet to be determined, health experts worldwide have suggested several theories which are currently under investigation.

As of May 29, 2022, genomic sequences of ten MPXV strains, associated with the recent countrywide outbreak, have been determined. [14] While all data suggests that the strain causing the recent viral surge is closely related to the West African clade [14], whether or not the virus underwent genetic mutations leading to its intensified transmissibility, remains unknown.

Health officials stopped recommending smallpox inoculation following the eradication of smallpox in the late nineties. [11] Given that smallpox and Monkeypox viruses belong to the same genus (Orthopoxvirus), the cessation of the smallpox vaccine resulted in populations developing a weakened immunity to MPXV. [11] The waning immunity against the virus over several years served as a nidus for infection, resulting in the latest re-surge. As per a study, almost five decades ago, MPXV was considered a “disease of young children”, predominately affecting children aged 4–5 years. By the 2000s, this number had increased five times, with ages 20–25 years old being most vulnerable to infection. [11] This is in line with the current data, which suggests that most of the recently reported MPXV cases have been in young men. [13] It is highly likely that most of these individuals were not administered the smallpox vaccine either because they were too young or were born after the termination of routine vaccination.

The resumption of everyday life following the Coronavirus-2019 (COVID-19) pandemic can also be attributed as a factor favoring MPXV spread. With the lifting of travel restrictions coupled with the easing of social distancing measures, individuals were more likely to have been in close physical contact, thereby encouraging viral transmission. [9] Moreover, the decline in the number of dendritic cells, and consequently the wearying immune system response post-COVID-19 infection, results in recovered individuals being more vulnerable to secondary infections [15]; the Monkeypox re-surge might be just another testament to this fact.

As of May 29, 2022, no cases of Monkeypox have been registered in Pakistan. While a high alert has been issued by the provincial health department and airport restrictions have been implemented to pre-empt a potential outbreak, [16] the lack of diagnostic facilities to detect the virus is an alarming matter requiring urgent addressing. [17] According to the World Health Organization's (WHO) guidelines, confirmed diagnosis of suspected MPXV cases is based on a conventional real-time polymerase chain reaction (PCR). [18] Even though most eminent Pakistani laboratories are equipped with PCR machines, they lack the testing kits required. [17] Given that diagnosing Monkeypox patients based on their symptoms is not a reliable approach, it is imperative that the Pakistani government urgently procures the required testing kits, primers, and reagents to combat a possible viral epidemic.

As a developing country recovering from the COVID-19 inflicted economic reparations, Pakistan cannot afford to bear the burden of an endemic. Raising awareness among healthcare providers and the general population, implementing strict surveillance measures and timely contact tracing (in case of a viral outbreak) are the best preventative measures to effectively prevent or manage a potential Monkeypox outbreak in the country. Per expert-issued guidelines, mass smallpox vaccination campaigns are not a requirement. Instead, a ring vaccination approach needs to be utilized, that is, to only vaccinate people in close contact with infected individuals. [8] This way the challenges presented due to the limited global supply of smallpox vaccine and the prevalent vaccination hesitancy [19] in Pakistan can be overcome, albeit to some extent.

In conclusion, despite public-health experts declaring Monkeypox a ‘containable disease’ (unlike COVID-19), the Pakistani government and health ministries must take this matter seriously and adequately prepare for a potential outbreak.

Ethical approval

This paper did not involve patients, therefore no ethical approval was required.

Sources of funding

No funding was acquired for this paper.

Author contribution

Hala Najeeb: conception of the study, drafting of the work, final approval and agreeing to the accuracy of the work. Zunera Huda: conception of the study, drafting of the work, final approval and agreeing to the accuracy of the work.

Registration of research studies

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Guarantor

Hala Najeeb, Zunera Huda.

Consent

This study was not done on patients or volunteers, therefore no written consent was required.

Declaration of competing interest

The authors declare that there is no conflict of interest.