Genetic Drift of HIV Populations in Culture

Populations of Human Immunodeficiency Virus type 1 (HIV-1) undergo a surprisingly large amount of genetic drift in infected patients despite very large population sizes, which are predicted to be mostly deterministic. Several models have been proposed to explain this phenomenon, but all of them implicitly assume that the process of virus replication itself does not contribute to genetic drift. We developed an assay to measure the amount of genetic drift for HIV populations replicating in cell culture. The assay relies on creation of HIV populations of known size and measurements of variation in frequency of a neutral allele. Using this assay, we show that HIV undergoes approximately ten times more genetic drift than would be expected from its population size, which we defined as the number of infected cells in the culture. We showed that a large portion of the increase in genetic drift is due to non-synchronous infection of target cells. When infections are synchronized, genetic drift for the virus is only 3-fold higher than expected from its population size. Thus, the stochastic nature of biological processes involved in viral replication contributes to increased genetic drift in HIV populations. We propose that appreciation of these effects will allow better understanding of the evolutionary forces acting on HIV in infected patients

Hantavirus infection epidemiology in Belgium

In Europe, Puumala (PUU) is a hantavirus responsible for a human disease called nephropathia epidemica and its natural reservoir is the red bank vole, (Clethrionomys glareolus). Although the population densities and the prevalence rates of infection were high in red bank voles in southern Belgium during the 1996 and 1999 epidemic years, the percentages of infected rodents were low in 1997 and 1998, when only a few positive sites were found. Antibodies against PUU virus were mainly detected in the red bank vole but also in the wood mouse (Apodemus sylvaticus) and the red fox (Vulpes vulpes). The analysis of genomic sequences has shown that the Belgian viruses and the German strain Erft constitute a genetic lineage well separated from the other European PUU strains

Characterization of divergent and atypical canine coronaviruses from Sweden

Field canine coronaviruses (CCVs) identified during a series of outbreaks of gastroenteritis in Swedish dogs were subjected to genetic analysis involving the open reading frame 1b (ORF1b) and the membrane (M) and spike (S) protein genes. Four field viruses originating from the Stockholm region presented identical sequences and segregated separately from other CCVs characterized so far and from GOT/05, the variant recovered in Western Sweden. A recombinant origin of the fifth virus identified in the Stockholm region is suggested. In addition, the five viruses originating from the same geographical area displayed atypical 5' S gene sequences

Incidence of hantavirus infections in Belgium

Over the last two decades, and from the moment that serological detection was possible, human hantavirus infections have been documented in most European countries. This paper summarises the available data on hantavirus cases in Belgium. These data enable the demonstration of the existence of a 3-year epidemic cycle in Belgium, which is apparently linked to rodent population dynamics

Rodent host specificity of European hantaviruses: Evidence of Puumala virus interspecific spillover

In order to investigate rodent host specificity of European hantaviruses, experimental infection of colonized and wild-trapped rodents was performed. In addition to the natural rodent reservoir, Clethrionomys glareolus, Puumala hantavirus (PUUV) could infect colonized Microtus agrestis and Lemmus sibiricus, but not Syrian hamsters or Balb/C mice. Neither C. glareolus, nor M. agrestis, could be readily infected by Tula hantavirus (TULV). Wild-trapped Apodemus flavicollis and A. agrarius, the natural reservoirs of Dobrava (DOBV) and Saaremaa (SAAV) hanta-viruses, respectively, could both be infected by SAAV. NMRI mice could also be infected by SAAV, but with lower efficiency as compared to Apodemus mice. Balb/C and NMRI laboratory mice, but not C. glareolus, could be infected by DOBV. To our knowledge, this is the first time DOBV and SAAV have been shown to infect adult laboratory mice. Moreover, potential hantavirus spillover infections were investigated in wild-trapped rodents. In addition to the natural host C. glareolus, we also found M. arvalis and A. sylvaticus with a history of PUUV infection. We did not find any C. glareolus or A. sylvaticus infected with TULV, a hantavirus which is known to circulate in the same geographical regions of Belgium. © 2002 Wiley-Liss, Inc.SCOPUS: ar.jFLWINinfo:eu-repo/semantics/publishe

Tula hantavirus in Belgium.

European common voles (Microtus arvalis), captured in Belgium in 1999, were proven by molecular as well as by serological techniques to be infected with Tula hantavirus (TULV). This is the first evidence for the presence of TULV in this country. No indication of spill-over infections of Puumala virus, known to be highly endemic among bank voles (Clethrionomys glareolus) within the same geographical regions as the trapped TULV-infected common voles, was observed. Together with previous reports on the circulation of TULV in eastern/central Europe, this finding suggests a more wide-spread circulation of this hantavirus serotype throughout the continent