How do you confirm a case of monkeypox?
Date : 2024.08.23
● Understand monkeypox: signs and symptoms
Monkeypox is a zoonotic virus similar to smallpox, with unique signs and symptoms. Early recognition of these signs and symptoms is essential for timely diagnosis and control. Common symptoms include acute fever, severe headache, muscle pain (myalgia), back pain, extreme weakness, and swollen lymph nodes (lymph nodes). The hallmark of monkeypox is its characteristic rash, which ranges from maculopapular to blistering and pustular. These lesions usually start on the face and then spread to other parts of the body, including the palms and soles of the feet, which is not common in other diseases that cause rashes.
● Preliminary assessment: Suspected case of monkeypox
Identification of suspected monkeypox cases requires evaluation of clinical manifestations and recent exposure history. According to the World Health Organization (WHO), a suspected case is an individual who has been in contact with a suspected or confirmed case of monkeypox in the 21 days prior to the onset of symptoms. This time period is critical because it corresponds to the incubation period of the monkeypox virus. Symptoms to watch out for include unexplained acute rashes, mucosal lesions, and systemic symptoms such as fever and myalgia. Given the overlap with other diseases, a thorough differential diagnosis is essential.
● Suspected cases: Bridging the diagnostic gap
A person is defined as likely to have monkeypox when he or she has an acute rash or mucosal lesion of unknown cause and has one or more of the following symptoms: an epidemiologic link to a confirmed case, multiple or temporary partners in the past 21 days, or tests positive for a posix-virus infection. Rashes, especially in the anogenital area, can be similar to other infections, so additional epidemiological and laboratory criteria are essential for accurate classification.
● Laboratory confirmation: Final diagnosis
Confirmation of monkeypox cases depends on laboratory testing, mainly through polymerase chain reaction (PCR) testing for viral DNA. This involves collecting samples from skin lesions, such as diseased fluid, skin crusts, or swabs from multiple sites. Real-time PCR is the gold standard because of its high sensitivity and specificity. Sequencing can also be used to detect unique viral DNA sequences to ensure accurate identification of the monkeypox virus. Rapid tests such as
monkeypox virus rapid tests are available from various vendors and can facilitate rapid initial screening, but must be confirmed by PCR.
● Dropping monkeypox cases: negative results and criteria
If the PCR test for the lesion fluid, skin sample or scab is negative for monkeypox virus, the case can be ruled out. However, it is important to note that if the level of clinical suspicion remains high, a negative result from a non-diseased sample (such as blood or oropharyngeal swabs) is not enough to rule out the disease. Proper sample collection and processing is essential to avoid false negatives. Cases should only be ruled out when all relevant laboratory and clinical evidence cannot support a monkeypox diagnosis.
Understand the Mpox death definition in surveillance
In surveillance, monkeypox related deaths are defined as suspected or confirmed cases unless there is another cause (such as trauma). This includes cases where monkeypox significantly caused death, even if it was not the primary cause. If there is sufficient lesion material for PCR testing, autopsy confirmation can also be performed. Accurate classification is essential for epidemiological tracking and resource allocation during outbreaks.
● Reinfection: Identify recurrent monkeypox cases
The criteria for reinfection are very strict, including documented previous monkeypox cases and current confirmed cases. Suspected reinfection is considered when a new episode of symptoms occurs without a clear clinical resolution of the previous symptom. A possible reinfection is a recurrence within three months of the first full recovery. Confirming reinfection requires at least three months between episodes and, where possible, genetic sequencing to distinguish strains.
● Contact tracing: Identify contacts
Effective contact tracing is essential to contain the outbreak, including identifying people who have been in contact with suspected or confirmed cases. This includes direct skin contact, exposure to contaminated substances, and prolonged face-to-face respiratory contact. Health workers without proper personal protective equipment also fall into this category. Comprehensive contact tracing helps early identification, isolation and prevention of further spread of the virus.
● Initial diagnostic testing: Best practice
The primary diagnostic tool for confirming monkeypox is PCR assay of skin lesion material. Alternative samples such as oral or nasopharyngeal swabs can be used, but are less reliable. Due to its low reliability, blood PCR and serology should not be used as the first line of diagnosis. Rapid diagnostic tests, such as the monkeypox virus rapid test, can provide rapid initial results, but should be followed by a confirmatory PCR test. Choosing the right test and sample type is crucial to an accurate diagnosis.
● Public health measures: prevention of monkeypox transmission
Public health measures are essential to control the spread of monkeypox. Isolating confirmed cases, proper use of personal protective equipment and vaccination are key strategies. Public health advice tailored to high-risk communities and environments can help minimize transmission. Vaccination, if available, can provide important protection, and public awareness campaigns play a vital role in educating the population about prevention and early detection.
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Colonki BiotechFounded in 2004, Hangzhou Colongi Biotechnology Co., Ltd. is a national high-tech enterprise specializing in biological raw materials, diagnostic reagents and CRO/CDMO services. With 20 years of industry experience, Colonki consistently delivers high quality products and professional technical services. Their products include antigens, antibodies and molecular diagnostic enzymes for a variety of diagnostic platforms. Colongi Biotech is committed to bringing more value to its global partners through innovative products and comprehensive services.