Nagpur College of Pharmacy, Hingna Road, Wanadongri, Nagpur 4401110
Monkeypox is an emerging zoonotic disease attributed to the monkeypox virus, which belongs to the Orthopoxvirus genus. Recently, this virus has been designated a global health emergency, prompting serious concerns regarding its transmission, pathogenesis, and clinical management. This review examines the origins, clinical symptoms, diagnostic approaches, and treatment alternatives for monkeypox, with a particular focus on comparisons with other poxviruses. We evaluate the effectiveness of antiviral therapies, smallpox vaccinations, and innovative diagnostic methods such as FDG-PET/CT imaging in elucidating disease progression. Additionally, the review highlights the significant influence of climate change and environmental factors on the transmission of monkeypox, emphasizing the contributions of deforestation, urbanization, and climate variations to the virus's resurgence and dissemination. A comparative analysis with other poxviruses enhances the understanding of the unique features of monkeypox and emphasizes the importance of ongoing surveillance, particularly in regions vulnerable to environmental changes. Ultimately, this review advocates for a comprehensive approach to monkeypox management, taking into account both clinical and ecological aspects to reduce the likelihood of future outbreaks.
Monkeypox is a zoonotic disease caused by an enveloped DNA virus that belongs to the Orthopoxvirus genus, which is part of the Poxviridae family and the Chordopoxvirinae subfamily1. The immune response of the host is pivotal in determining the progression of the disease and its clinical features. Infections with the monkeypox virus primarily result in skin lesions, which are a significant concern during the current outbreak, and provoke a robust immune response that can lead to deep tissue abscesses, severe respiratory complications, and damage to various organs2(Tehranchinia et al., 2023a; Zaib et al., 2023)?. Recent concerns have arisen regarding the human-to-human transmission of the monkeypox virus, which can occur through close contact with infected individuals or animals, as well as through contaminated surfaces3(Jezek et al., 1983a)?. The World Health Organization has declared this situation a global health emergency in Africa, emphasizing that transmission can occur from animals to humans and between humans.4 The early clinical signs, including fever, myalgia, headache, and lymphadenopathy, are essential for initial diagnosis. Laboratory diagnostic methods, such as conventional polymerase chain reactions (PCR) and real-time PCR (RT-PCR), are the most common and reliable techniques for identification. Additionally, assessing altered metabolic activity at sites involved in the immune response through Fluorodeoxyglucose and positron emission tomography/computed tomography imaging offers an effective approach to pinpointing critical disease-specific time points and locations relevant to pathogenesis and treatment? (Dyall et al., 2017a)?.5 Antiviral treatments are utilized to address viral infections, with most targeting specific viruses. For monkeypox, antiviral medications such as tecovirimat and brincidofovir are employed. Although there is no specific vaccine for monkeypox, existing smallpox vaccines have shown efficacy in enhancing immunization rates, as evidence indicates that monkeypox infection rates were lower among individuals who had received smallpox vaccinations compared to those who had not6 ?(Liu et al., 2024a; Karagoz et al., 2023)? Multiple factors such as decline in cross- protective herd immunity( cessation of smallpox vaccination), deforestation, civil war, refugee displacement, enhanced global association and even changes in climatic conditions may facilitate the unexpected appearance of the disease.1
2. Characteristics of Monkeypox
2.1 Origin and transmission
Human-to-human transmission can take place via sexual intercourse, inhalation of respiratory droplets, and direct contact with the skin. After inoculation, the viruses multiply swiftly and spread into the bloodstream, resulting in viremia that affects various organs, including the skin, gastrointestinal tract, genitals, lungs, and liver7 (Niu et al., 2023)?. The transmission of the virus from rodents to primates occurs through exposure to contaminated bodily fluids, skin lesions, and respiratory droplets. It is crucial to differentiate the Monkeypox virus from other Poxviruses during the diagnostic process, which can be effectively accomplished through DNA analysis of swab samples8 ?(Zaib et al., 2023)?.
2.2 Symptoms
The disease begins with symptoms that are similar to those of influenza, including fever, headaches, muscle and back pain, swollen lymph nodes, chills, and fatigue. The virus is transmitted from rodents to primates via infected bodily fluids, skin lesions, and respiratory droplets. After infection, patients generally exhibit fever, muscle pain, a maculopapular rash, and fluid-filled blisters. A distinctive rash typically appears first on the face before spreading to other parts of the body. This rash progresses through several stages, starting with flat lesions, then developing into raised bumps, followed by fluid-filled blisters, and eventually forming scabs 8?(Zaib et al., 2023)?.
2.3 Diagnosis
It is essential to differentiate the monkeypox virus from other poxviruses during the diagnostic assessment, a process that can be efficiently achieved through DNA analysis of swab samples ?(Zaib et al., 2023)?. The uptake of fluorodeoxyglucose in lymphoid tissues acts as a prognostic marker in the non-human primate model of monkeypox virus infection. The integration of fluorodeoxyglucose (FDG) with positron emission tomography-computed tomography (PET/CT) enhances the visualization of altered metabolic activity in regions associated with the immune response. This imaging technique is a vital resource for identifying significant disease-specific timeframes and locations, which are crucial for understanding pathogenesis and guiding treatment approaches. Furthermore, FDG-PET/CT imaging offers real-time observations of changes in metabolic activity due to viral infections (Dyall et al., 2017b)5.? The assessment of clinical symptoms, alongside laboratory diagnostic tests such as conventional polymerase chain reaction (PCR) or real-time PCR (RT-PCR), remains the most prevalent and dependable diagnostic approach.
2.4 Treatment
The evidence suggests that smallpox vaccination considerably reduces the likelihood of experiencing severe Monkeypox. Third-generation vaccines have shown greater effectiveness in comparison to their first-generation counterparts. The smallpox vaccination is effective in stimulating the production of neutralizing antibodies against the Monkeypox virus6. Additionally, vaccination with the vaccinia virus for the prevention of smallpox is also beneficial against Monkeypox, due to a significant degree of sequence conservation?9 (Keasey et al., 2010)?. The JYNNEOS vaccine, which is approved for use against the Monkeypox virus, presents fewer adverse effects than previous smallpox vaccines and has demonstrated immunogenicity against Monkeypox in animal research8. Infections caused by the Monkeypox virus elicit strong B-cell and T-cell responses, whereas immunization with JYNNEOS results in more robust T-cell responses10 ?(Cohn et al., 2023)?.
3. Pathophysiology of Monkey Pox
Monkeypox is mainly spread through two primary routes: from animals to humans and from person to person. The transmission from animals to humans can occur when handling or consuming infected meat, through direct contact with the blood and bodily fluids of infected animals, or as a result of bites from these animals11. Human-to-human transmission takes place via skin lesions, contaminated surfaces, and respiratory droplets. Once the virus enters the host's body, it begins to replicate and subsequently disseminates through the bloodstream to the lymph nodes and other lymphoid tissues. This process is followed by an initial phase of viremia, which is then succeeded by a secondary phase. As the infection progresses, individuals may exhibit symptoms such as skin rashes, fever, back pain, headaches, and swollen lymph nodes12 ?(Karagoz et al., 2023)?.
4. Comparative analysis with other poxviruses
Infections caused by the monkeypox virus elicit pronounced B-cell and T-cell responses when contrasted with other poxviruses. Research indicates that the monkeypox virus exhibits a greater virulence compared to its related counterparts, with lymphadenopathy being a prominent characteristic of monkeypox infections, a symptom typically absent in other poxvirus infections. Furthermore, the emergence of skin lesions in monkeypox occurs at a markedly slower pace ?(Jezek et al., 1988; MacNeil et al., 2009). Unlike other poxviruses, the transmission of monkeypox necessitates an animal reservoir. While a vaccine for smallpox exists, there is presently no vaccine available for monkeypox. Additionally, a notable increase in leukocyte migration has been observed in monkeypox infections relative to other poxviruses ?(Liu et al., 2024b; Song et al., 2013; McFadden, 2005; Depero & Bontempi, 2023)?
|
Sr.no |
Features |
Monkey-pox |
Other Poxviruses |
|
1. |
Response of B-cell and T-cell |
vigorous |
Lower than monkey pox13 (37475115) |
|
2. |
Lymphadenopathy |
Present |
Absent 14(2907258) |
|
3. |
virulence |
More virulent15 |
Less Noxious 19346366 |
|
4. |
Appearance of skin lesion |
slower |
Faster as compared to monkey pox16 2907258 |
|
5. |
Animal reservoir |
present |
Absent17 33167496 |
|
6. |
Vaccination |
Not available |
For smallpox-available18 . 36403582 |
|
7. |
Leukocyte migration and activation (induction of genes) |
Yes |
No(exception-cowpox)1924147080 |
|
8. |
Cellular tropism |
broader |
Narrower 2015738948 |
5. Variation in monkey pox due to climate changes
Monkeypox is a viral zoonotic disease that is re-emerging and is primarily found in the intentionally forested areas of West and Central Africa21. The disease was first recognized in Zaire in 1970 and, while it shares some clinical characteristics with smallpox, it demonstrates considerable differences in its epidemiological behavior22. Over the past fifty years, monkeypox has been reported in various regions across Africa 23(Reynolds et al., 2019a)?. Climate change is recognized as a significant factor affecting the environment, economy, and society, as well as influencing the variability in the transmission of infectious diseases?24 (Jezek et al., 1983b)?. Elements such as globalization, urban expansion, alterations in ecosystems, deforestation, and changes in agricultural and livestock management practices contribute to the dynamics of disease dissemination25 ?(Delfraissy, 2023)?. Several elements may account for the unexpected resurgence of monkeypox, including the reduction in cross-protective immunity following the cessation of smallpox vaccinations, deforestation, civil unrest, population displacement, and climate variations26. It is noteworthy that monkeypox cases are more commonly reported during the dry season, with children under the age of ten constituting 84 percent of the documented cases27 Significant environmental elements affecting the disease encompass yearly precipitation, diverse temperature indicators, primary productivity, water evaporation, soil moisture levels, and other associated factors28. Deforestation and climate play pivotal roles in the proliferation of the monkeypox virus, with forecasts indicating a heightened potential for the virus in the eastern part of the Democratic Republic of Congo29. Several variables influence the identification of MPVX in waste water, such as the routes and duration of viral shedding by those infected, the prevalence of infections within the community, environmental circumstances, and the efficacy and sensitivity of the analytical techniques employed30
6. Future Direction
The recent emergence of the monkeypox virus has intensified worries about the urgent need for effective vaccines and therapeutic options. It is crucial to create dependable diagnostic tests for accurately identifying the monkeypox virus, especially in comparison to other poxviruses. To mitigate the risk of transmission through human contact, individuals are advised to avoid close interactions with infected persons. Existing treatment guidelines, combined with the innovation of new antiviral drugs, could play a significant role in controlling its dissemination.
7. CONCLUSION
The monkeypox virus is classified within the same taxonomic family as other poxviruses; however, it exhibits notable differences in terms of epidemiology, transmission patterns, and clinical manifestations. This review emphasizes the unique characteristics of monkeypox, particularly its zoonotic origins, transmission methods, and the wide range of symptoms it can cause, which set it apart from other poxviruses such as smallpox. Furthermore, the ongoing shifts in global climate and environmental conditions are exacerbating the spread of the virus. Factors like deforestation, which disrupts wildlife habitats and increases human-animal interactions, along with civil unrest and the forced migration of populations, have created an environment that facilitates the virus's spread. The global interconnectedness through travel and trade further amplifies the risk of outbreaks in new areas. The impact of climate change is not merely an ancillary issue; it is central to the resurgence and increased transmission of monkeypox, as warmer climates and altered ecosystems enable vectors to thrive and expand. This scenario, combined with socio-political instability, has led to more frequent and widespread outbreaks. Given these complexities, it is imperative to prioritize the development and distribution of vaccines and antiviral treatments specifically targeting monkeypox. Current preventive measures and therapies are inadequate, and without a focused public health response, monkeypox could become a persistent global health challenge. Proactive strategies, including the establishment of global surveillance systems, improvement of diagnostic capabilities, and ensuring equitable access to medical resources, are vital to mitigate the impact of future outbreaks. Effective international cooperation in addressing these issues will not only reduce the burden of monkeypox but also safeguard against the emergence and re-emergence of similar zoonotic threats.
REFERENCES
Yamin Ansari*, Ashwini Pawar, Krutika Channe, Vinod Thakare, Understanding Monkey pox: A Comparative Analysis with Other Poxviruses and Environmental Influences, Int. J. of Pharm. Sci., 2025, Vol 3, Issue 1, 371-379. https://doi.org/10.5281/zenodo.14607580
10.5281/zenodo.14607580
