Transmission of hepatitis C virus among people who inject drugs: viral stability and association with drug preparation equipment

Abstract

Background: Hepatitis C virus (HCV) transmission among people who inject drugs remains a challenging public health problem. We investigated the risk of HCV transmission by analyzing the direct association of HCV with filters, water to dilute drugs, and water containers.

Methods: Experiments were designed to replicate practices by people who inject drugs and include routinely used injection equipment. HCV stability in water was assessed by inoculation of bottled water with HCV. Viral association with containers was investigated by filling the containers with water, inoculating the water with HCV, emptying the water, and refilling the container with fresh water. Transmission risk associated with drug preparation filters was determined after drawing virus through a filter and incubating the filter to release infectious particles.

Results: HCV can survive for up to 3 weeks in bottled water. Water containers present a risk for HCV transmission, as infectious virions remained associated with water containers after washing. Physical properties of the water containers determined the degree of HCV contamination after containers were refilled with water. HCV was also associated with filter material, in which around 10% of the viral inoculum was detectable.

Conclusions: This study demonstrates the potential risk of HCV transmission among injection drug users who share water, filters, and water containers and will help to define public health interventions to reduce HCV transmission.

Figure 1.

Stability of hepatitis C virus (HCV) in bottled water. A, Cell culture-grown Jc1 viral particles with a titer of 10⁶ median tissue culture infective doses (TCID₅₀)/mL were spiked at different concentrations into 100 mL of drinking water in plastic containers and incubated for several days at room temperature. At indicated time points, samples were collected and used to inoculate naive Huh7.5 cells. Infectivity was determined by a limiting dilution assay, and viral titers are displayed as TCID₅₀. A representative experiment of 3 independent repetitions is shown with SDs of infection replicates. B, HCV RNA at the respective time points of the 200 µL virus spike was isolated and quantified by real-time reverse transcription polymerase chain reaction. A representative experiment of 3 independent repetitions is shown with SDs of the means.

Figure 2.

Association of hepatitis C virus (HCV) with different container materials. A, Three water containers of different materials were filled with 100 mL of standard drinking water and spiked with 40 µL of cell culture–grown Jc1 virus. A 1-mL sample was collected (virus spike), and the remaining water was discarded. The same containers were filled with 100 mL of drinking water and tested for associated infectivity by concentration of the complete liquid suspension in centricons (recovery concentrated). After inoculation of viral samples on naive Huh7.5 cells, infectivity was determined by a limiting dilution assay, and viral titers are displayed as median tissue culture infective doses (TCID₅₀). A representative experiment of 3 independent repetitions is shown with SDs of infection replicates. B, HCV RNA of the respective samples was isolated and quantified by real-time reverse transcription polymerase chain reaction. A representative experiment of 3 independent repetitions is shown with SDs of mean values.

Figure 3.

Association of hepatitis C virus (HCV) with drug preparation filters. Viral suspensions of 800 µL were drawn through a cigarette filter, using a syringe and present the filtered output. Contaminated filters were stored for indicated time periods at room temperature without (A) or with (B) standard household foil. Associated infectious particles were released by incubation of filters in 1 mL of cell culture medium, infectious particles in filters were released by incubation of filters in 1 mL of cell culture medium for 5 minutes at 37°C under shaking. Infectivity was determined by infection of naive Huh7.5 cells and performance of a luciferase reporter assay. A representative experiment of 3 independent repetitions is shown with SDs of mean values.