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Higher concentrations of HIV-1 in serum aid viral transmission
SCIENCE AND MEDICINE
Warsaw conference on emerging infections in central and eastern Europe n March 28–29, epidemiologists and microbiologists convened in Warsaw, Poland, to discuss emerging, re-emerging, and drug-resistant infections in central and eastern Europe. Attending the meeting were representatives from the Czech Republic, Greece, Hungary, Latvia, Poland, Romania, Russia, and Yugoslavia, but with the exception of the USA and the UK, no other western countries sent delegates. Some of the worstaffected countries in central-eastern Europe in terms of infectious-disease morbidity were not represented either. A common focus for prevention in eastern-bloc states had been vaccination. Delegates heard that the diphtheria epidemics in several countries in the mid-1990s resulted from breakdown of vaccination campaigns following social dislocation. Although diphtheria morbidity has now been brought back down to expected levels through targeted vaccination programmes, fundamental socioeco-
O
nomic problems continue to threaten public health. Thus, the evolution of tuberculosis and HIV/AIDS remains largely unpredictable, the delegates were told. M Grzemska (WHO, Geneva, Switzerland) said that Russia has the greatest tuberculosis burden of any country in Europe, and that Romania, the Baltic states, and Caucasian and central-Asian republics are all facing a steadily increasing incidence of the disease, with central Asia experiencing rates similar to those of developing countries. Participants heard that the incidence of multidrug-resistant tuberculosis is also growing in such countries. Major problems in tuberculosis control include late diagnosis, non-existent or erratic drug supplies, and unreliable reporting. In parts of Poland, up to 40% of cases go undetected. A sharp rise in HIV/AIDS and injecting drug use has recently been recorded throughout the area. The
“syringe ecosystem”, both in healthcare settings and for injecting drug users, was singled out by P Alcabes (Hunter College School of Health Sciences, New York, USA) for its crucial role as a vector of HIV and hepatitis B and C. Appropriate intervention strategies need to be developed urgently, he said. Delegates agreed that central and eastern European public-health is cruelly under financed. Surveillance systems throughout the WHO European region must therefore be supported, refined, and co-ordinated to a much greater degree than at present, they said. Western Europe and the USA must become more involved through ongoing exchange of all kinds. The overriding importance of providing specialised training and the building up of networks of public-health specialists was a recurrent theme throughout the conference. Marta Aleksandre Balinska
Identification of taste-receptor family may improve patients’ compliance
S
cientists in the USA believe they have identified a family of G-protein-coupled receptors that mediate perception of substances that taste bitter. If such receptors could be blocked, bitter medications could be made palatable, and compliance could be improved. Two possible G-protein-coupled bitter/sweet taste receptors have been identified previously, but because of the chemical diversity of bitter and sweet compounds, Hiroaki Matsunami and colleagues (Harvard Medical School, Boston, MA, USA) proposed that a much larger number of related receptors
might exist. Matsunami and colleagues used a database of G-protein-coupled receptor sequences to search a region of chromosome 12 that corresponds to a murine locus known to be involved in the detection of the bitter compound sucrose octa-acetate. They found one gene encoding a G-protein-coupled receptor in the region of interest, and after more searching, identified six closely related genes on chromosome 12, and one on chromosome 5. The latter was within a locus that governs our ability to detect the bitter compound 6-n-propyl-2-thiouracil.
The researchers identified a series of five similarly related genes in mice, and used in-situ hybridisation to show that the genes were expressed only in the taste-receptor cells of the taste buds (Nature 2000; 404: 601–04). In an accompanying News and Views article, Stuart Firestein (Columbia University, New York, USA) suggests that compliance may be improved if bitter medicines could be made more palatable: “The development of bitter antagonists is now within reach”. Zoë Mullan
Higher concentrations of HIV-1 in serum aid viral transmission ndividuals with higher concentrations of HIV-1 in serum are more likely to infect their partners than those with lower values, report Thomas Quinn (Johns Hopkins University, Baltimore, MD, USA) and colleagues. A ten-fold increase in HIV-1 RNA concentration more than doubled HIV-1 transmission. “The results suggest that interventions that lower viral loads may reduce transmission”, Quinn says. The researchers prospectively studied 415 heterosexual Ugandan cou-
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ples; one partner was HIV-1 positive and one was HIV-1 negative. 90 of the HIV-1-negative partners seroconverted in the 30-month study (incidence 11·8 per 100 personyears), with the highest incidence of seroconversion among those 15–19 years of age (15·3 per 100 personyears) and among women with uncircumcised partners (16·7 per 100 person-years). No seroconversions occurred among women with circumcised partners. The rate of transmission was zero in participants with less
than 1500 copies of HIV-1 RNA per mL serum, 2·2 in those with less than 3500 copies per mL, and 32 in those with 50 000 or more copies per mL (N Engl J Med 2000; 342: 921–29). In an accompanying editorial, Myron Cohen (University of North Carolina, NC, USA) comments that the study confirms the importance of infectiousness in HIV-1 transmission, and begins to show a dose–response effect for the infection. Khabir Ahmad
THE LANCET • Vol 355 • April 8, 2000
Warsaw conference on emerging infections in central and eastern Europe n March 28–29, epidemiologists and microbiologists convened in Warsaw, Poland, to discuss emerging, re-emerging, and drug-resistant infections in central and eastern Europe. Attending the meeting were representatives from the Czech Republic, Greece, Hungary, Latvia, Poland, Romania, Russia, and Yugoslavia, but with the exception of the USA and the UK, no other western countries sent delegates. Some of the worstaffected countries in central-eastern Europe in terms of infectious-disease morbidity were not represented either. A common focus for prevention in eastern-bloc states had been vaccination. Delegates heard that the diphtheria epidemics in several countries in the mid-1990s resulted from breakdown of vaccination campaigns following social dislocation. Although diphtheria morbidity has now been brought back down to expected levels through targeted vaccination programmes, fundamental socioeco-
O
nomic problems continue to threaten public health. Thus, the evolution of tuberculosis and HIV/AIDS remains largely unpredictable, the delegates were told. M Grzemska (WHO, Geneva, Switzerland) said that Russia has the greatest tuberculosis burden of any country in Europe, and that Romania, the Baltic states, and Caucasian and central-Asian republics are all facing a steadily increasing incidence of the disease, with central Asia experiencing rates similar to those of developing countries. Participants heard that the incidence of multidrug-resistant tuberculosis is also growing in such countries. Major problems in tuberculosis control include late diagnosis, non-existent or erratic drug supplies, and unreliable reporting. In parts of Poland, up to 40% of cases go undetected. A sharp rise in HIV/AIDS and injecting drug use has recently been recorded throughout the area. The
“syringe ecosystem”, both in healthcare settings and for injecting drug users, was singled out by P Alcabes (Hunter College School of Health Sciences, New York, USA) for its crucial role as a vector of HIV and hepatitis B and C. Appropriate intervention strategies need to be developed urgently, he said. Delegates agreed that central and eastern European public-health is cruelly under financed. Surveillance systems throughout the WHO European region must therefore be supported, refined, and co-ordinated to a much greater degree than at present, they said. Western Europe and the USA must become more involved through ongoing exchange of all kinds. The overriding importance of providing specialised training and the building up of networks of public-health specialists was a recurrent theme throughout the conference. Marta Aleksandre Balinska
Identification of taste-receptor family may improve patients’ compliance
S
cientists in the USA believe they have identified a family of G-protein-coupled receptors that mediate perception of substances that taste bitter. If such receptors could be blocked, bitter medications could be made palatable, and compliance could be improved. Two possible G-protein-coupled bitter/sweet taste receptors have been identified previously, but because of the chemical diversity of bitter and sweet compounds, Hiroaki Matsunami and colleagues (Harvard Medical School, Boston, MA, USA) proposed that a much larger number of related receptors
might exist. Matsunami and colleagues used a database of G-protein-coupled receptor sequences to search a region of chromosome 12 that corresponds to a murine locus known to be involved in the detection of the bitter compound sucrose octa-acetate. They found one gene encoding a G-protein-coupled receptor in the region of interest, and after more searching, identified six closely related genes on chromosome 12, and one on chromosome 5. The latter was within a locus that governs our ability to detect the bitter compound 6-n-propyl-2-thiouracil.
The researchers identified a series of five similarly related genes in mice, and used in-situ hybridisation to show that the genes were expressed only in the taste-receptor cells of the taste buds (Nature 2000; 404: 601–04). In an accompanying News and Views article, Stuart Firestein (Columbia University, New York, USA) suggests that compliance may be improved if bitter medicines could be made more palatable: “The development of bitter antagonists is now within reach”. Zoë Mullan
Higher concentrations of HIV-1 in serum aid viral transmission ndividuals with higher concentrations of HIV-1 in serum are more likely to infect their partners than those with lower values, report Thomas Quinn (Johns Hopkins University, Baltimore, MD, USA) and colleagues. A ten-fold increase in HIV-1 RNA concentration more than doubled HIV-1 transmission. “The results suggest that interventions that lower viral loads may reduce transmission”, Quinn says. The researchers prospectively studied 415 heterosexual Ugandan cou-
I
1246
ples; one partner was HIV-1 positive and one was HIV-1 negative. 90 of the HIV-1-negative partners seroconverted in the 30-month study (incidence 11·8 per 100 personyears), with the highest incidence of seroconversion among those 15–19 years of age (15·3 per 100 personyears) and among women with uncircumcised partners (16·7 per 100 person-years). No seroconversions occurred among women with circumcised partners. The rate of transmission was zero in participants with less
than 1500 copies of HIV-1 RNA per mL serum, 2·2 in those with less than 3500 copies per mL, and 32 in those with 50 000 or more copies per mL (N Engl J Med 2000; 342: 921–29). In an accompanying editorial, Myron Cohen (University of North Carolina, NC, USA) comments that the study confirms the importance of infectiousness in HIV-1 transmission, and begins to show a dose–response effect for the infection. Khabir Ahmad
THE LANCET • Vol 355 • April 8, 2000