A novel method to identify routes of hepatitis C virus transmission.
BACKGROUND
We propose a new approach based on genetic distances among viral strains to infer about risk exposures and location of transmission at population level.


METHODS
We re-analysed 133 viral sequences obtained during a cross-sectional survey of 4020 subjects living in a hepatitis C virus (HCV) endemic area in 2002. A permutation test was used to analyze the correlation between matrices of genetic distances in the NS5b region of all pairwise combinations of the 133 viral strains and exposure status (jointly exposed or not) to several potential HCV risk factors.


RESULTS
Compared to subjects who did not share the same characteristics or iatrogenic exposures, the median Kimura genetic distances of viral strains were significantly smaller between brothers and sisters (0.031 versus 0.102, P<0.001), mother and child (0.044 versus 0.102, P<0.001), father and child (0.045 versus 0.102, P<0.001), or subjects exposed to periodontal treatment (0.084 versus 0.102, P = 0.02). Conversely, viral strains were more divergent between subjects exposed to blood transfusions (0.216 versus 0.102, P = 0.04) or tooth filling or extraction (0.108, versus 0.097, P = 0.05), suggesting acquisition of the virus outside of the village.


CONCLUSIONS
This method provided insights on where infection took place (household, village) for several socio-demographic characteristics or iatrogenic procedures, information of great relevance for targeting prevention interventions. This method may have interesting applications for virologists and epidemiologists studying transmission networks in health-care facilities or among intravenous drug users.
Inserm 955, Hopital Henri Mondor, Créteil, France.
Cyrille
C
Féray
Institut Pasteur, Unité d'Epidémiologie des Maladies Emergentes, Paris, France.
Julie
J
Bouscaillou
Unité INSERM 669, La maison de Solenn, Paris, France.
Bruno
B
Falissard
Department of Community, Environmental and Occupational Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
Mostafa K
MK
Mohamed
Department of Community, Environmental and Occupational Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
Naglaa
N
Arafa
Department of Community, Environmental and Occupational Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
Iman
I
Bakr
Department of Community, Environmental and Occupational Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
Mostafa
M
El-Hoseiny
National Liver Institute, Menoufia University, Shebeen El-Kom, Menufia, Egypt ; Viral Hepatitis Research Laboratory, National Hepatology and Tropical Medicine Research Institute, Cairo, Egypt.
Mai El
ME
Daly
National Liver Institute, Menoufia University, Shebeen El-Kom, Menufia, Egypt ; Viral Hepatitis Research Laboratory, National Hepatology and Tropical Medicine Research Institute, Cairo, Egypt.
Sherif
S
El-Kafrawy
Unité INSERM 550, Paris, France.
Sabine
S
Plancoulaine
Viral Hepatitis Research Laboratory, National Hepatology and Tropical Medicine Research Institute, Cairo, Egypt ; Department of Microbiology, Faculty of Medicine, Minia University, Minya, Egypt.
Mohamed
M
Abdel-Hamid
Unité INSERM 785, Centre Hépato-Biliaire, Villejuif, France.
Valérie
V
Thiers
Institut Pasteur, Unité d'Epidémiologie des Maladies Emergentes, Paris, France ; Conservatoire National des Arts et Métiers, Chaire Santé et Développement, Paris, France.
Arnaud
A
Fontanet
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D015331:Cohort Studies; D004279:DNA, Viral / Q000235:genetics; D004534:Egypt / Q000453:epidemiology; D004812:Epidemiologic Methods; D005260:Female; D016174:Hepacivirus / Q000235:genetics*; D006526:Hepatitis C / Q000453:epidemiology / Q000635:transmission* / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D017361:Viral Nonstructural Proteins / Q000235:genetics; D055815:Young Adult; D012324:RNA-Dependent RNA Polymerase
D004279:DNA, Viral; D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase