RESUMO
Zika virus (ZIKV) has recently caused a large epidemic in the Americas that is associated with birth defects. Although ZIKV is primarily transmitted by Aedes mosquitoes, ZIKV RNA is detectable in blood and semen of infected individuals for weeks or months, during which sexual and other modes of transmission are possible. However, viral RNA is usually detectable longer than infectious virus is present. We determined the frequency of isolation of infectious virus from semen and serum samples prospectively obtained from a cohort of patients in Puerto Rico. We confirmed isolation of infectious virus on the basis of a tissue culture cytopathic effect, an increase in virus genome copy equivalents (GCE), and positive results of immunofluorescence analysis; virus in infected cells was quantitated by flow cytometry. These criteria confirmed the presence of infectious virus in semen specimens from 8 of 97 patients for up to 38 days after initial detection when virus loads are >1.4 × 106 genome copy equivalents/mL. Two serum isolates were obtained from 296 patients. These findings can help guide important prevention guidelines for persons that may potentially be infectious and transmit ZIKV sexually.
Assuntos
RNA Viral/isolamento & purificação , Sêmen/virologia , Infecção por Zika virus/sangue , Zika virus/isolamento & purificação , Animais , Linhagem Celular Tumoral , Chlorocebus aethiops , Feminino , Humanos , Masculino , Estudos Prospectivos , Porto Rico , RNA Viral/sangue , Manejo de Espécimes , Células Vero , Carga Viral , Replicação Viral , Zika virus/fisiologiaRESUMO
Quantitative analysis of the scientific literature is important for evaluating the evolution and state of science. To study how the density of biological literature has changed over the past two decades we visually inspected 1464 research articles related only to the biological sciences from ten scholarly journals (with average Impact Factors, IF, ranging from 3.8 to 32.1). By scoring the number of data items (tables and figures), density of composite figures (labeled panels per figure or PPF), as well as the number of authors, pages and references per research publication we calculated an Average Publishable Unit or APU for 1993, 2003, and 2013. The data show an overall increase in the average ± SD number of data items from 1993 to 2013 of approximately 7±3 to 14±11 and PPF ratio of 2±1 to 4±2 per article, suggesting that the APU has doubled in size over the past two decades. As expected, the increase in data items per article is mainly in the form of supplemental material, constituting 0 to 80% of the data items per publication in 2013, depending on the journal. The changes in the average number of pages (approx. 8±3 to 10±3), references (approx. 44±18 to 56±24) and authors (approx. 5±3 to 8±9) per article are also presented and discussed. The average number of data items, figure density and authors per publication are correlated with the journal's average IF. The increasing APU size over time is important when considering the value of research articles for life scientists and publishers, as well as, the implications of these increasing trends in the mechanisms and economics of scientific communication.