Major Sponsor: Clinipath Pathology Dr Smathi Chong Clinical Microbiologist Clinipath Pathology – Not Always Simple

Herpes simplex (HSV) 1 and 2 are HSV has a more limited role. Many The highest risk is in symptomatic primary closely related to each other and more clinicians (and patients) expect Herpes herpes of the birth canal/genital distantly related to serology to be able to do more than it can! track. (VZV), which causes Varicella (chicken Test results may not answer many clinical or pox) and Herpes Zoster (). patients’ questions. Herpes simplex serology may be more useful in the setting of pregnancy in patients with Traditionally HSV1 causes most oral herpes A positive serology simply indicates a patient genital suggestive of herpes to help and HSV2 causes most . has been infected with HSV at some time risk stratify whether the episode is likely to be But this is no longer so and has changed, in the past. It is not able to time the initial primary HSV. The highest risk would be PCR probably due to more frequent . infection unless (HSV IgG proven active genital lesions and negative changing from negative to positive) can be serology. Figures from Clinipath 2017: demonstrated. In Herpes reactivation, the IgG would already be positive. Treatment including anti-viral therapy HSV Swab Origin HSV1 HSV2 VZV and consideration of Oral sites 93% 2% 5% Serology does not indicate the site of infection may be discussed with the obstetrician. (e.g. oral or genital) although a strong positive Management of the neonate with high risk of Genital/perineal sites 45% 50% 5% HSV2 serology in the setting of painful HSV should be handled by a neonatologist or genital lesions is likely to indicate genital paediatrician. HSV1 is frequently acquired in childhood herpes. Serology does not confirm whether and 75% of Australian adults would have had symptoms are due to herpes. A positive PCR Treatment HSV1 by early adulthood. This would have on a genital would be more helpful. These may be treated with , been from oral contact with close friends and or . relatives who were shedding the virus, often Positive serology is not able to tell if the asymptomatically. The classic “cold sores” person is infectious at the time of the test. Detailed therapeutic advice is beyond the are a blistering painful around the mouth. HSV Serology or PCR would NOT be able to scope of this article. Guidelines may be determine whether a person’s partner has obtained from the Therapeutic Guidelines Like other viruses in the Herpes family, this been unfaithful! and from the King Edward Memorial Hospital ‘lifelong’ infection can lay dormant and (KEMH) website for management of HSV in reactivate. The risk of reactivation and severe False positive (perhaps up to 5%) and false pregnancy and in neonates reactivation is higher in immunosuppressed negative serology results can occur. individuals but in most people there is Further Reading: Australian STI Management Guidelines no readily identifiable reason for their Australian Therapeutic Guidelines reactivation. Stress is often blamed. King Edward Memorial Hospital Guidelines Less common include: så (36åENCEPHALITISå(36åINåADULTS åANDå(36å meningitis (usually HSV2 in adults) så #ONJUNCTIVITISKERATITISånåUSUALLYå(36åORå VZV (shingles affecting ) så (ERPETICåWHITLOWånåPAINFULåVESICLESå affecting the fingers and thumb caused by HSV1 or 2 Genital Herpes Key Points This causes most angst in patients as there Serology is often negative in acute primary is a social stigma. Approximately 1 in 7 herpes infection as HSV IgG can take a few så (36åANDå(36åMAYåBEåCLINICALLYå of the general Australian adult population weeks to a few months to become positive. indistinguishable is seropositive to HSV2 but most are Serology positivity may also decline over time. så $IAGNOSISåOFåCHOICEåISå0#2åFROMåAå or subclinical. ‘dry swab’ or viral transport medium HSV IgM is no longer performed in most labs testing as they often throw up more confusion due to så (36å3EROLOGYåISåOFåMOREåLIMITEDåUTILITY HSV PCR is performed on a swab of a lesion the non-specific nature of the test. så (36åINåPREGNANCY åESPECIALLYåPRIMARYå genital infection, needs to be taken to detect viral DNA. It is the test of choice for HSV in Pregnancy diagnosis of HSV infections. Clinical diagnosis seriously may be confirmed by swabs of the lesions/ HSV can cause severe neonatal infections så !NTIVIRALSåAREåAVAILABLEåFORåTREATMENTå vesicles for HSV PCR. This can accurately including meningo-, disseminated or viral suppression distinguish between HSV1, HSV2 and VZV. and even death.

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