Administrative Office
St. Joseph's Hospital Site, L301
50 Charlton Avenue East
HAMILTON, Ontario, CANADA L8N 4A6
PHONE: (905) 521-6141
FAX: (905) 521-6142
Issue No. 90
QUARTERLY NEWSLETTER
April 2007
Type-specific Herpes Simplex Virus Serology
Genital Herpes (GH) is one of the most common Sexually Transmitted Infections (STI), however, access
to clinically valuable tests is limited and is often associated with a high cost for patients. Most cases are
caused by type 2 Herpes Simplex Virus (HSV-2). The prevalence of HSV-2 has been evaluated in
Canada with seropositivity rates in women in British Columbia at 17.3%1, 19% in an STD clinic in
Alberta2 and greater than 20% in men and women over the age of 40 in Ontario.3 The incidence of this
infection is not known in Canada but has been shown to be increasing in the United States.4 Type 1
Herpes Simplex Virus (HSV-1) is also an important cause of GH with Canadian reports of up to 58% of
cases caused by HSV-15.
Genital Herpes is a challenging infection to treat. Effective management requires not only drug therapy
for symptomatic recurrences, but also counseling for dealing with the psychological impact of the
infection.4,6,7 HSV may have a significant psychological impact on patients due to the fact that infection
is lifelong and there is a risk of transmission to all subsequent sexual partners. Effective counseling can
have a positive impact on patient well-being and improve quality of life.6 Important issues to be covered
when counseling patients include the natural history of the infection, clinical recurrences and risks of
transmission.6 These issues differ depending on the type of herpes simplex causing the infection.4,7
HSV-2 infected patients can be informed that the median number of recurrences is four per year 8,9, high
rates of asymptomatic shedding occur12, oral infection alone is rare, condom use >25% of the time
significantly protects against HSV-2 acquisition among women7 and chronic suppressive therapy has
been shown to reduce the risk of transmission to seronegative partners10. For HSV-1 infections the
patient can expect a median recurrence rate of less than one per year8,9, oral infection alone is common,
less asymptomatic shedding occurs4 and less data is available addressing the benefit of chronic
suppressive antiviral therapy for reducing the risk of transmission.
There are few tests available for diagnosing genital herpes. The most readily available test is viral
culture, which can detect both HSV-1 and HSV-2 and provide the type specific information which is
important for clinical management. This test is somewhat limited as up to 60% of infected patients do
not have any symptoms of genital herpes11 and therefore have no lesions for swabbing.12 Culture is also
limited by the fact that the yield from culture decreases as the age of the lesion increases. 13 PCR is at
least four times more sensitive than culture for HSV during periods of viral shedding14, however it is
offered by few laboratories. Type-specific serology can be used to detect infection with HSV-1 and
HSV-2. Routine serology is not reliable in distinguishing between the two types of virus, however
newer, commercial type-specific serologic tests which are based on glycoprotein G are now available
and are more accurate for serotyping15.
- 2 Type-specific serology is useful for managing select populations such as pregnant women, discordant
couples (where one has a herpes infection and is seropositive, the other does not and is seronegative),
HIV infected patients, patients with atypical lesions, and high risk patients 15,16. Patients who are
seropositive for HSV-2 have genital herpes4 while HSV-1 seropositivity must be interpreted in the
context of the clinical presentation. Despite its clinical utility, type specific serology for herpes simplex
virus is not widely available and has a price tag which prohibits its use in many patients.
1) Patrick DM, Dawar M, Cook DA, Krajden, Ng HC, Rekart ML. Antenatal seroprevalence of Herpes simplex virus
type 2 (HSV-2) in Canadian women: HSV-2 prevalence increases throughout the reproductive years. Sex Trans Dis.
2001; 28:424-428.
2) Singh AE, Romanowski B, Wong T et al. Herpes simplex virus seroprevalence and risk factors in 2 Canadian
sexually transmitted disease clinics. Sex Trans Dis 2005; 32: 95-100.
3) Howard M, Sellers JW, Jang D, Robinson N.J, Fearon M, Kaczorowski J and Chernesky M. Regional Distribution
of Antibodies to Herpes Simples virus Type 1 (HSV-1) and HSV-2 in men and women in Ontario, Canada. J Clin
Micro 2003; 41(1): 84-89.
4) Aoki F.Y. Genital Herpes Simples Virus. Canadian STD Treatment Guidelines. 2006.
5) Forward KR, Lee SHS. Predominance of herpes simplex virus type 1 from patients with genital herpes in Nova
Scotia. Can J Infect Dis 2003; 14:94-6.
6) Clarke P. The impact of a herpes diagnosis and the implications for patient counseling. In: Sacks SL, Straus SE,
Whitley RJ, Griffiths PD, eds. Clinical Management of Herpes Viruses. Burke, VA: IOS Press, Inc.; 1995:75-86.
7) Leone P. Reducing the risk of transmitting genital herpes: advances in understanding and therapy. Current Medical
Red and Opin. 2005; 21(10):1577-82.Corey L, Adams HG, Brown ZA et al. Genital herpes simplex virus infections:
Clinical manifestations, course and complications. Ann Intern Med. 1982;98:958-72.
9) Benedetti J, Corey L, Ashley R. Recurrence rates in genital herpes after symptomatic first-episode infections. Ann
Intern Med. 1994; 121:847-54.
10) Corey et al. Once-Daily Valacyclovir to reduce the risk of transmission of genital herpes. New England J Med.
2004; 350:11-20.
11) Corey L, Adams HG, Brown ZA, Holmes KK. Genital herpes simples infections: clinical manifestations, course
and complications. Ann Intern Med. 1983; 98:958-972.
12) Mertz G.J, Benedetti J, Ashley R, Selke SA, Corey L. Risk factors for the transmission of genital herpes. Ann
Intern Med. 1992; 116:197-202.
13) Kimberlin D.W, Rouse D.J. Genital herpes. New England J Med. 2004; 350:1970-77.
14) Wald A, Huang M-L, Carrell D, Selke S, Corey L. Polymerase chain reaction for detection of herpes simples virus
(HSV) on mucosal surfaces: comparison with HSV isolation in cell culture. J Infect Dis. 2003; 188:1345-51.
15) Wald A, Ashley-Morrow R. Serological testing for Herpes Simplex Virus (HSV)-1 and HSV-2 Infection. CID.
2002; 35: 173-182.
16) Guerry S.L, Bauer H.M, Klausner J.D, Branagan B, Kerndt P.R, Allen B.G and Bolan G. Recommendations for the
selective use of herpes simples virus type 2 serological tests. CID. 2005; 40: 38-45.
Dr. Cheryl Main
Discipline of Microbiology
Directory, Hamilton STI Clinic
Hamilton Regional Laboratory Medicine Program
Hamilton General Hospital Site