On June 18, 2025, a 37-year-old male, who had recently returned from Saudi Arabia, was admitted to Sukraraj Tropical and Infectious Disease hospital with the complaints of rash, fever and lethargy. The following day, a polymerase chain reaction (PCR) test confirmed that he had the Mpox virus. This is the first reported Mpox case in Nepal in 2025. Previously, Nepal reported three instances of Mpox, two of which involved Nepali citizens who had also returned from Saudi Arabia. This case, however, was clinically different from the previous cases.

Mpox, also known as monkeypox, was first identified in monkeys kept for research in Denmark in 1958. It was detected in humans for the first time in the Democratic Republic of Congo (DRC) in 1970. Since then, the virus has been commonly observed in Africa, particularly in Central and West African countries. The region has been classified into two distinct clades: the Central African (or Congo Basin) Clade and the West African Clade, now called Clade I and II, respectively.

Clade I is considered to be more severe (case fatality rate up to 10 percent) compared to Clade II (case fatality rate up to 3.6 percent). In 2022, Mpox caused an outbreak beyond Africa for the first time. Clade IIb was responsible for this outbreak, which spread even to Nepal. This outbreak led to a Public Health Emergency of International Concern (PHEIC) declaration in July 2022, which ended in May 2023. However, the virus re-emerged in 2023 and was again declared an emergency in 2024. This time, Clade I was responsible for the outbreak.

In the DRC, Clade I is believed to predominantly affect children, with 67 percent of cases and 78 percent of deaths among individuals aged 15 years and younger. Although Nepal continues to detect imported Mpox cases, the presence of Clade I has not yet been confirmed.

Signs and symptoms of Mpox can appear between 1-21 days after exposure, and typically last for 2-4 weeks. Common symptoms include rash, fever, sore throat, headache, lethargy and swollen lymph nodes. The first symptom can be a rash, fever or sore throat. In the case of the 37-year-old Saudi returnee, the patient first noticed a rash, followed by chills and fatigue. Generally, the rash first appears on the face and then spreads across the body, including the palms and soles of the feet. However, in this patient, the rash first appeared on the abdomen, followed by the face and one hand.

As observed in many Mpox cases worldwide, the patient did not develop a rash in the genital or anal areas. Moreover, unlike cases reported elsewhere, the rashes did not progress to blisters and were not painful. Therefore, it can be concluded that the classical symptoms and typical rash distribution patterns associated with Mpox were not observed in this patient. To date, no specific antiviral medication for Mpox exists, and vaccines are not available on the market or in pharmacies in Nepal.

The most striking concern in this case is the unclear source of infection. The patient reported having sexual contact six months ago, while his roommate was diagnosed with a sexually transmitted disease three months ago. After returning to Nepal, he also reported having sexual contact with his wife. This raises important questions: Could the infection have been transmitted by his partner (maybe in an asymptomatic phase), given that the incubation period for Mpox can be as short as one day? Alternatively, could the incubation period extend beyond the previously established maximum of 21 days, given the patient’s reported history of sexual contact six months ago and his roommate’s contraction of a sexually transmitted disease—raising the possibility of Mpox transmission—three months ago? This timeline of potential exposures challenges the current understanding of the virus’s incubation period and warrants further research.

It would be prudent to conduct orientation sessions on infectious diseases for individuals planning to travel to countries where Mpox is circulating. According to the patient, over 80 percent of workers at his workplace in Saudi Arabia were Nepali, indicating a significant risk of potential Mpox transmission among this population in the coming days. In addition to awareness programmes, it is advisable to recommend Mpox vaccination for individuals departing to Saudi Arabia and other countries where the virus is endemic or actively circulating. Such preventive measures could reduce the risk of infection among the Nepali population residing or working abroad.

In summary, the clinical presentations of the three Nepali individuals infected with Mpox (including two from the previous year) have not been consistent with one another. In other words, the current patient showed an atypical clinical presentation of Mpox infection. Thus, individuals with a history of travel to Mpox-endemic countries who develop a rash—regardless of its location on the body—should seek medical attention and undergo testing for the virus.

The continued importation of Mpox cases from Saudi Arabia necessitates the recommended Mpox vaccination for Nepalis, who are planning to travel to, or reside in, or work in this country or regions (The Middle East) for an extended period. Such preventive measures could significantly reduce the risk of infection among Nepalis and help prevent the potential spread of the virus within Nepal, given that thousands of Nepalis travel to and from Middle Eastern countries each week. Many may not seek medical care or testing even after developing signs and symptoms of Mpox.

Hence, proactive measures, such as vaccination and pre-departure health education, play a key role in mitigating the potential risk of an Mpox outbreak in Nepal in the coming days.