In a recent study published in Eurosurveillance, researchers described the spread of monkeypox virus (MPX) (MPXV) in the city of Barcelona, Spain.
Study: Frequent detection of monkeypox virus DNA in saliva, semen and other clinical samples of 12 patients, Barcelona, Spain, from May to June 2022. Image credit: FOTOGRIN/Shutterstock
Background
MPX was first detected in the Democratic Republic of the Congo in 1970, and a non-endemic outbreak of MPX occurred in the United States (USA) in 2003. From then on, MPX was considered an emerging infectious disease and a potential threat to public health. To date, MPX continues to expand globally, with more than 9,000 confirmed cases of MPX reported in 57 countries as of July 11, 2022.
From 2018 to 2021, there were seven cases in the UK with MPXV deoxyribonucleic acid (DNA) detected in urine, blood and nasopharynx samples. Furthermore, four cases detected in Italy showed the presence of MPXV DNA in saliva, feces and semen. The continuing rise in MPX cases warrants a greater understanding of MPXV clearance.
About the study
In the present study, researchers characterized MPX shedding to improve understanding of the potential role of body fluids in MPXV transmission.
The study was conducted between May and June 2022, for which 147 samples including saliva, rectal swabs, semen, nasopharyngeal swabs, urine, and feces were obtained from 12 MPXV-positive patients at 23 different time points by reaction in real-time polymerase chain reaction (PCR). In addition, Sanger sequencing was performed for the first three MPX cases diagnosed. Epidemiological and clinical data were retrieved from patient records and retrospectively reviewed.
Samples were obtained from two lesions for the diagnosis of MPX, and additionally, samples were analyzed for other sexually transmitted infections (STIs) by PCR: Mycoplasma genitalium, Chlamydia trachomatis, Neisseria gonorrhoeae and in the rectum, urine and pharynx, respectively. In addition, serological screening was performed for lymphogranuloma venereum, Treponema pallidum and herpes virus in anal genital ulcers and human immunodeficiency virus (HIV), hepatitis B and C viruses and syphilis.
Results and Discussion
All participants were young men who have sex with men (MSM), their median age was 38.5 years, most of them (nine patients) had a history of STIs, and concurrent STIs were reported among three participants. All participants were sexually active and had ≤10 sexual partners in the past month, seven of whom were taking HIV pre-exposure prophylaxis (PEP) medications.
Five participants attended sex sessions on the premises or chemsex, and three participants traveled within Spain, although none of them visited Madrid or the Canary Islands, where MPXV transmission was initially detected in the country. Four participants had sexual intercourse with confirmed cases of MPX and four patients had received the smallpox vaccine.
MPXV DNA was detected in saliva and skin lesion samples from all cases (12/12), with high viral loads [quantification cycle (Cq) values ranging between 16 and 21] in the skin pustules. In addition, MPXV DNA was detected in samples obtained between day 4 and day 16 after the onset of MPX symptoms.
Other samples were frequently positive for MPXV: nasopharyngeal swabs (10 cases), rectal swabs (11 cases), semen (seven cases), feces (eight cases), and urine (nine cases). Intermittent shedding of MPXV (PCR-negative samples that became PCR-positive) was observed in the saliva and urine samples of two participants.
The study results are in agreement with previous studies that reported the detection of MPXV DNA in semen, blood, nasopharyngeal swabs, saliva, and feces. Of interest, saliva was previously analyzed only once in one patient. In the present study, MPXV DNA was detected in saliva samples from all patients obtained 4 to 16 days after symptom onset.
Conclusions
Overall, the study findings highlighted the transmission routes of MPX in Barcelona and improved understanding of the spread of MPXV. The results of the study could provide valuable information for the diagnosis of MPX and the development of interventions to improve public health. However, more research is needed to determine the ability of MPXV to cause proctitis and several other unusual clinical manifestations.
Additionally, future studies with larger sample sizes should further assess the infectivity of bodily fluids and their potential role in MPX transmission by close physical contact during sexual intercourse. Furthermore, data on smallpox vaccination history from large case series along with serological tests should be analyzed to improve understanding of the beneficial role of smallpox vaccines in protection against MPXV infections. In addition, the frequency of asymptomatic and secondary cases should be evaluated, and the impact of MPX on behavioral and social factors that affect MPX transmission should be evaluated.
Source: www.news-medical.net