PTK and PDPT do not reduce re-infection rates in women with chlamydia compared with patient referral. However, PDPT may offer other advantages such as simplicity and cost compared with patient referral.

To investigate the mechanism and functional significance of infection of CD8؉ lymphocytes by human immunodeficiency virus type 1 (HIV-1) in vivo, we determined frequencies of infection, proviral conformation, and genetic relationships between HIV-1 variants infecting naive (CD45RA ؉ ) and memory (CD45RO ؉ ) peripheral blood CD4 ؉ and CD8 ؉ lymphocytes. Infection of CD3 ؉ CD8 ؉ CD45RA ؉ cells was detected in 9 of 16 study subjects at frequencies ranging from 30 to 1,400 proviral copies/10 6 cells, more frequently than CD3 ؉ CD8؉ lymphocytes expressing the RO isoform of CD45 (n ‫؍‬ 2, 70 and 260 copies /10 6 cells). In agreement with previous studies, there was no evidence for a similar preferential infection of CD4 ؉ naive lymphocytes. Proviral sequences in both CD4؉ and CD8 ؉ lymphocyte subsets were complete, as assessed by quantitation using primers from the long terminal repeat region spanning the tRNA primer binding site. In six of the seven study subjects investigated, variants infecting CD8 ؉ lymphocytes were partially or completely genetically distinct in the V3 region from those recovered from CD4؉ lymphocytes and showed a greater degree of compartmentalization than observed between naive and memory subsets of CD4 ؉ lymphocytes. In two study subjects, arginine substitutions at position 306, associated with use of the chemokine coreceptor CXCR4, were preferentially found in CD4 lymphocytes. These population differences may have originated through different times of infection rather than necessarily indicating a difference in their biological properties. The preferential distribution of HIV-1 in naive CD8؉ lymphocytes indeed suggests that infection occurred early in T-lymphocyte ontogeny, such as during maturation in the thymus. Destruction of cells destined to become CD8 ؉ lymphocytes may be a major factor in the decline in CD8؉ lymphocyte frequencies and function on disease progression and may contribute directly to the observed immunodeficiency in AIDS.

Although it is established that infection with GB virus C (GBV-C) or hepatitis G virus (HGV) can be transmitted parenterally, the prevalence of GBV-C/HGV viremia in the general population (2-5%) is relatively high compared with other parenterally borne viruses such as hepatitis C virus. To investigate the possibility of sexual transmission of GBV-C/HGV, we determined the frequency of viremia by the polymerase chain reaction and serological reactivity to the E2 protein by ELISA in samples collected from individuals at risk for sexually transmitted diseases attending a city genitourinary medicine clinic. GBV-C/HGV viremia was detected in 27 of 87 male homosexuals (31%) and 9 of 50 prostitutes (18%), frequencies significantly greater than those in matched controls (2/63) and local blood donors (2.3%). Among nonviremic individuals, a high frequency of serological reactivity to the E2 protein of GBV-C/HGV was also observed in the risk groups (male homosexuals: 14/60; prostitutes: 11/41), although these figures are likely to be underestimates of the frequency of past infection as detectable anti-E2 reactivity may attenuate rapidly over time following resolution of infection. Infection with GBV-C/HGV was more frequent among those coinfected with human immunodeficiency virus type 1. Among male homosexuals from whom retrospective samples were available, evidence for de novo infection was found in 9 of 22 individuals over a mean sampling time of 2.9 years, predicting an annualized incidence of GBV-C/HGV infection of approximately 11% in this group. The high prevalence and incidence of GBV-C/HGV infection in these individuals and prostitutes provides strong evidence for its spread by sexual contact. Further studies are required to investigate the mechanism of its transmission and the clinical significance of acute and persistent infection in these risk groups.

Transmission of the mite Sarcoptes scabiei generally occurs by protracted direct body contact; although in crusted scabies, transmission also occurs via infected clothing or bedding. Diagnosis is usually clinical and topical antiscabietics are the mainstay of treatment. Oral ivermectin is not licensed in most countries, but may have a role in certain patients. Treatment of sexual contacts is indicated.

TT virus (TTV), a recently discovered DNA virus, has been implicated as a cause of non-A to non-C posttransfusion hepatitis. The frequency of TTV in persons considered at high risk for sexual and parenteral infection was investigated (52 prostitutes, 81 homosexual men, 65 intravenous drug users) to assess its mode of transmission. TTV DNA was assayed by polymerase chain reaction using primers from conserved regions in the N22 clone. Viremia frequency was 4.5%-13.0% in study subjects, not significantly different from that in low-risk controls (2 [4.5%] of 44). The frequency of TTV viremia increased significantly with age (P=.018) but was not associated with human immunodeficiency virus coinfection. The low frequency of infection detected in both risk groups suggests that spread by sexual contact or by intravenous drug use is relatively inefficient and unlikely to account for the high prevalence of TTV observed worldwide.