80% in adultsA DNA herpes virus consisting of types EBV1 and EBV2. Infects >90% of humans, persisting for life. Probably evolved from a non-human primate virus.
Virtually all children infected in developing countries (especially with socio-economic deprivation).
In developed countries most infections are acquired by those aged 15–25 years. Characteristically spread by ingestion of infected saliva from a seropositive carrier during kissing. Although unproven, reports of EBV isolated from a vulval ulcer, semen, and cervical secretions, suggest the potential for sexual transmission.
Incubation period: 4–6 weeks. Infection in children usually asymptomatic. In adolescents and young adults >50% present with infectious mononucleosis (glandular fever):
• >10% develop hepatosplenomegaly and palatal petechiae (Forscheimer spots).
Other less common features include anaemia (haemolytic and aplastic), thrombocytopenia, myocarditis, hepatitis, genital ulcers, Guillain–Barré syndrome, encephalitis, and meningitis.
Non-specific diffuse central rashes may be found in up to 50% with an immune complex macular rash and in >70% of those taking ampicillin or amoxicillin.
• Haematology: lymphocytosis with 20% of cells atypical. May also be thrombocytopenia.
• Biochemistry: elevated liver enzymes in up to 100%.
• Monospot test—heterophil antibodies; sensitivity 80% in adults
• EBV antibody tests—IgM to viral capsid antigen (transient); most reliable test is paired IgG showing >4-fold titre rise; IgG to EBV nuclear antigen (EBNA) appears in convalescence, denotes past infection
• EBV PCR can be used to detect virus in blood and/or CSF if significant complication.
• Bed rest, analgesics, antipyretics.
• Antibiotics (not ampicillin/amoxicillin) if 2° bacterial infection.
• Steroids if airways obstruction.
Self-limiting, although associated with persisting tiredness and possible relapses during the first 6–12 months.
These include:
• Burkitt’s and Hodgkin’s lymphomas.
The largest known DNA herpesvirus; host-specific, with four human/higher primate subtypes.
Worldwide distribution favouring developing countries and low socioeconomic classes. Spread through contact with infected saliva (kissing), urine, genital fluids (cervical, vaginal seminal), breastmilk, and blood. Infection with multiple strains reported in sexually active individuals. 
rates found in those with history of STIs, BV, seroprevalence proportional to number of lifetime partners. In STI clinics, prevalence of CMV antibodies in MSM is about 1.5 times that of heterosexual ♂.
Most common vertically transmitted viral infection. Worldwide incidence of foetal CMV acquisition during pregnancy 0.8–4%. In UK 50% ♀ becoming pregnant are CMV seronegative, with 3% becoming infected during their pregnancy (largely from young children). 30–40% with 1° infection and about 1% with recurrent CMV will infect their foetus (overall congenital infection rate 0.5–1%).
Acquired by foetal ingestion of infected amniotic material, haematological transplacental spread, and lactation.
• Generally causes asymptomatic infection unless immunosuppressed.
• Only 10% of 1° infections cause an infectious mononucleosis type illness, consisting of fever, myalgia, cervical lymphadenopathy, and less commonly pneumonitis and hepatitis.
• Illness self-limiting, although lifelong viral persistence, often with extended periods of asymptomatic viral shedding (e.g. during pregnancy).
Severity of neonatal symptoms/signs less if mother seropositive (neutralizing antibodies). Range from none (in about 80%) to the classical congenital syndrome—hepatosplenomegaly (with jaundice) and thrombocytopenia (with purpura), which are self-limiting. Less common, but permanent CNS features include microcephaly, chorioretinitis, a progressive sensorineuronal deafness.
• Immunocompetent adults: serology; 4-fold in IgG CMV antibodies from paired blood samples taken 10–14 days apart or IgM from single specimen (persists up to 20 weeks).
• Foetal infection: CMV detection from amniotic fluid by PCR after 21 weeks gestation.
• Congenital/neonatal infection: cmv culture or pcr from urine and pharynx.
Symptomatic treatment (as for EBV infection, see Chapter 26, ‘Epstein–Barr virus’, p. 324).
For CMV associated with HIV infection see Chapter 44, ‘HIV: Disorders’ of the eye’, pp. 513–521.
A number of other viruses may be sexually transmitted, including Zika virus, Marburg haemorrhagic fever virus, Lassa virus, Ebola virus, and many of the other haemorrhagic fever viruses.
It is likely that other viruses will be found to have significant sexual transmission in the future. For highly significant viruses, such as the category 4 haemorrhagic fever viruses, that are known to be transmitted via seminal fluid, condoms should be used or abstinence should be practiced. Sexual transmission may occur months after the symptomatic phase is over (varying between viruses). Seminal fluid may be taken for PCR.
If PCR is negative on 2 separate occasions, it is thought that transmission is unlikely to occur. Specialist advice should be sought.
Zika virus is now endemic in many countries within the tropics. It is mainly transmitted through mosquito bite, but sexual transmission can occur.
If contracted during pregnancy, birth defects can occur, including microcephaly. It is advised that pregnant women consider carefully the risks of travelling to areas where Zika is endemic and, if travel is undertaken, avoid mosquito bites, where possible, with insect repellent and bed nets.
♀ should avoid becoming pregnant up to 8 weeks after travel and ♂ should use condoms for 6 months. Testing is available for symptomatic patients who are ill within 2 weeks of travel or during travel, and should be considered in those who have travelled and have become pregnant or whose partner has become pregnant within the above time periods (8 weeks for ♀ or 6 months for ♂).
Single-stranded RNA retrovirus.
Endemic in Japan and parts of the Caribbean, South America, and sub- Saharan Africa. Main transmission routes are breastfeeding and sexual intercourse (mostly heterosexual), but also from blood products and sharing injecting drug equipment.
Serology: enzyme immunoassay for HTLV antibody must be followed up by PCR or Western blot. HTLV testing is recommended in transplant for donor and recipient, blood transfusion, and in pregnant women from high-prevalence areas.
Most infected individuals remain healthy carriers adult T-cell leukaemia (ATL) or myelopathy (cumulative lifetime risk 1–4%).
Leukaemic involvement with wide-ranging skin lesions in 40%. Other manifestations include hepatosplenomegaly, lymphadenopathy, hypercalcaemia, and sometimes immunosuppression.
Demyelination of long motor neurons of spinal cord producing lower- extremity weakness, spasticity, urinary incontinence, and erectile dysfunction.
ATL has poor prognosis (median survival without treatment <1 year). Besides conventional chemotherapy and allogeneic stem-cell transplantation, other therapeutic approaches include interferon alfa plus zidovudine, and retinoid derivatives. Mogamulizumab (monoclonal antibody against CCR4) may have activity by reducing proviral DNA and is under investigation in ATL and myelopathy.
Herpes virus with five major variants (A–E). Variants B and C predominate in Europe and the USA.
Sexual contact, particularly oro-anal sex, and also mouth-to-mouth contact as HHV-8 is found in saliva. Implicated in close family contact in endemic areas (Africa), especially when associated with poor hygiene. In developed countries rates among MSM. Transmission does not appear to be related to pregnancy or breastfeeding.
• Associated with >95% of cases of Kaposi’s sarcoma with immunosuppression an important co-factor, although now less common with use of antiretroviral treatment (Chapter 54, ‘Kaposi’s sarcoma’, p. 596).
• Associated with Castleman’s disease—of nearly all HIV cases (Chapter 54, ‘Multicentric Castleman’s disease’, p. 617) and ~50% of non-HIV cases