Historically, monkeypox outbreaks have been primarily present in Central and West Africa. This zoonotic infection is brought on by the monkeypox virus (MPXV), which belongs to the Poxviridae family of the Orthopoxvirus genus. Until 2022, the incidence of monkeypox outside Africa was a rare event.

The recent detection of monkeypox outside Africa was found to be linked to patients’ household contacts. Interestingly, a monkeypox case outside Africa was reported in 2003 connected to importing exotic pets.

Study: Ten-Week Follow-Up of Monkeypox Case-Patient, Sweden, 2022. Image Credit: MIA Studio/Shutterstock

Background

The monkeypox outbreaks in Australia, Europe, Israel, and the U.S., were reported in May 2022. This infection was predominantly present in men involved in sexual intercourse with other men. Interestingly, in comparison with the previous outbreaks, the brand new monkeypox outbreak exhibited distinct clinical symptoms with localized rashes and mucosal lesions, mainly within the genital area. Other than these clinical manifestations, patients with monkeypox also suffered lymphadenopathy and fever. 

In a recent monkeypox case in Sweden, scientists focussed on clinical symptoms, viral kinetics, and microbial diagnostics. Moreover, bioinformatic evaluation of genomic sequences was performed. This case study is obtainable in Emerging Infectious Diseases.

Case study

The present study analyzed a male patient with monkeypox from Sweden. He didn’t have a history of smallpox vaccination and was otherwise healthy. The patient reported an inguinal swelling on day 0, with a manifestation of a small skin change on his foreskin the next day. This modification within the foreskin quickly transformed right into a deeper and well-circumscribed lesion with local lymphadenopathy inside the subsequent few days.

On the fifth and sixth day, fever developed peaking at 39°C. The patient sought care at an outpatient clinic after per week from the symptom onset. During this time, the fever subsided and no recent lesions erupted.

The patient reported receiving oral sex from several male partners, inside the three weeks before the manifestation of clinical symptoms. On day 11, the lesions increased to 2 cm in diameter. Clinicians performed microbiologic analyses for syphilis, herpes simplex virus, and Haemophilus ducreyi, and all tests were negative. The patient was also subjected to MPXV evaluation on the Public Health Agency of Sweden.

The actual-time PCRs evaluation for orthopoxvirus DNA and MPXV DNA was conducted using the genital swab samples. This test showed a positive result that was reconfirmed using the Sanger sequencing method. 

Although the genital lesions healed, local lymphadenopathy increased. On day 25, the patient suffered a ruptured lymph node with discharge. During a follow-up visit on day 25, he was reported to be feeling significantly better; nonetheless, he had enlarged lymph nodes. Moreover, the genital lesions also reduced to five mm and only bled barely when touched. The ruptured lymph nodes also healed during this era.

Throughout the ten-week follow-up, clinicians collected repeated samples from the ruptured local lymph node, urine, blood, semen, respiratory tract, and genital lesion. MPXV DNA was detected from most samples. Nevertheless, genital samples, which initially tested positive, exhibited a rapid decline within the viral DNA content. MPXV DNA was detected in ruptured lymph node samples 40 days after symptoms onset. Similarly, the virus was present in semen samples after 54 days and in saliva after 76 days.

Electron microscopic evaluation of skin lesions revealed characteristic of orthopoxviruses that were 220–450-nm long and 140–260-nm wide. Metagenomics sequencing of the extracted DNA sample from genital lesions helped the viral genomic reconstruction. This evaluation strongly indicated that the case virus belonged to the West African clade. Moreover, a single-nucleotide polymorphism distance of 4nt was observed.

Implications

Monkeypox is being reported each day in numerous countries. The clinical symptoms and transmission route of recent cases have been found to be different from previous monkeypox infection symptoms. These recent points strongly influence the clinical management of the infection, and the formulation of public health measures. There may be an urgent need to manage the monkeypox outbreak at an early stage and forestall further transmission of infection.

Many vital pieces of knowledge regarding monkeypox have been highlighted on this case study. As an example, the clinical manifestation of single genital lesions and enlarged local lymph nodes were observed. These clinical manifestations clearly indicated that the MPXV strain, related to the 2022 monkeypox outbreak, is different from previous outbreaks. 

The brand new strain related to the incidence of localized lesions is significantly different from the classic generalized rash or vesicles that spread over the body. As well as, rupture of the lymph nodes can also be a recent symptom. Interestingly, differential viral kinetics were also observed in numerous samples over time. The persistence of MPXV DNA in semen and respiratory samples implicates the transmission route.

Phylogenetic analyses showed that the brand new strain of virus belongs to the Western African clade of monkeypox, which has exhibited lower mortality rates in comparison with the Central African clade. The present study presented a quick and accurate bioinformatic evaluation to categorise viruses at a comparatively low price.