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    Transmission of Hepatitis C Virus
     
    Mohamed A Daw*
     
    Professor of Clinical Microbiology & Microbial, Epidemiology, Faculty of Medicine, Tripoli, Libya
     
    *Corresponding author: Mohamed A Daw, Professor of Clinical Microbiology & Microbial, Epidemiology, Faculty of Medicine, Tripoli, Libya, E-mail: mohamedadaw@gmail.com
     
    1. Introduction

    1.1 Background

    Hepatitis C has been considered to be the most commonly emerging viral Hepatitis worldwide with major universal devastating consequences. Every year, a round four million people are infected with the Hepatitis C Virus and over 150 million people are chronically infected and at risk of developing liver cirrhosis and/or liver cancer. More than 350 000 people die from Hepatitis C-related liver diseases every year. Hepatitis C is an infectious disease affecting primarily the liver caused by the Hepatitis C Virus (HCV). The existence of Hepatitis C (originally “non-A non-B Hepatitis”) was postulated in the 1970s and proven in 1989.Hepatitis C infects only humans and chimpanzees [1].

    Transmission of HCV has been changed immensely since its discovery, Blood and blood products was the primary mood of transmission particularly prior to 1992, though nowadays has been replaced by IUDs. Further it has been changed according the clinical status of infected individuals as the viral particles were confined to the serum and lymphocytes in acute and chronic cases of HCV, though in occult cases, the virus is not detectable with conventional testing but can be found with ultra-sensitive tests. Methods of transmission has been reflected considerably on the geo-epidemiology of HCV worldwide, in the developing countries where the prevalence of HCV is IUD is accounted for up to 90% of reported cases though in developing countries as they have the highest prevalence rates, blood, nosocomial and occupational transmission methods still taking the lead [2,3].

    This chapter aims to high light the method of transmission of HCV and outlining the preventive measure to be taken to minimize the spread of Hepatitis C Virus.

    1.2 Nature of Hepatitis C Virus particle

    Hepatitis C Virus belongs to the genus Hepacivirus a member of the family Flaviviridae. Until recently it was considered to be the only member of this genus. However a member of this genus has been discovered in dogs-canine Hepacivirus. There is also at least one virus in this genus that infects horses. Several additional viruses in the genus have been described in bats and rodents.

    As illustrated in (Figure 1), Hepatitis C Virus particle consists of a core of genetic material (RNA), surrounded by an icosahedral protective shell of protein, and further encased in a lipid (fatty) envelope of cellular origin. Two viral envelope glycoproteins, E1 and E2, are embedded in the lipid envelope.
     
     
    Figure 1: Diagrammatic illustration of Hepatitis C Viral particles.
     
    Hepatitis C Virus has a positive sense single-stranded RNA genome. The genome consists of a single open reading frame that is 9600 nucleotide bases long. This single open reading frame is translated to produce a single protein product, which is then further processed to produce smaller active proteins. At the 5' and 3' ends of the RNA are the UTR that are not translated into proteins but are important to translation and replication of the viral RNA. The 5' UTR has a ribosome binding site (IRES - Internal Ribosome Entry Site) that starts the translation of a very long protein containing about 3,000 amino acids. The core domain of the Hepatitis C Virus (HCV) IRES contains a four-way helical junction that is integrated within a predicted pseudo knot. The conformation of this core domain constrains the open reading frame's orientation for positioning on the 40S ribosomal subunit. The large pre-protein is later cut by cellular and viral proteases into the 10 smaller proteins that allow viral replication within the host cell, or assemble into the mature viral particles. Structural proteins made by the Hepatitis C Virus include Core protein, E1 and E2; nonstructural proteins includeNS2, NS3,NS4, NS4A, NS4B, NS5, NS5A, and NS5B.

    1.3 Environment and survival conditions of Hepatitis C Virus

    Environmental and survival conditions vary greatly from on pathogen to another and it was found to play an important role in Transmission of viruses. Compared to other viruses, HCV is a relatively hardy pathogen. The half-life of the virus particles in the serum is around 3 hours and may be as short as 45 minutes. In an infected person about 1012 virus particles are produced each day. In addition to replicating in the liver the virus can multiply in lymphocytes. Like many viruses, the Hepatitis C Virus is gradually inactivated outside the body of a host. The presence of heat can have a drastic impact on the virus's lifespan outside the body. The virus can remain infectious outside a host for about sixteen days at 25°C and two days at 37°C, while it can remain active for more than six weeks at temperatures less than or equal to 4°C. When heated to temperatures of 60°C and 65°C, however, the Hepatitis C Virus can be inactivated in eight and four minutes, respectively [4,5].

    Several variables have a direct impact on how long HCV can survive outside the body. Testing blood on exposed surfaces while considering the surface’s texture, room temperature, amount of blood exposed, viral load (low/high) and various contaminants in the environment makes the determination of how long Hepatitis C survives outside the body very complex. Infectivity studies in a chimpanzee suggest that HCV may survive on environmental surfaces at room temperature at least 16 hours but not longer than 4 days. The potential for HCV to survive in the environment re-emphasizes the importance of cleaning and disinfection procedures, safe therapeutic injection practices, and harm reduction counseling and services for injection drug users [6-8].

    HCV Known to survive outside the body for days in dried blood on surfaces, Hepatitis C can persist for months in a liquid medium under favorable conditions. According to the U.S. Centers for Disease Control and Prevention, HCV can survive on environmental surfaces at room temperature for at least 16 hours but no longer than four days. In contrast, the HIV virus can only live on surfaces for several hours. Recent advances in on the survival of HCV have shown;

    - HCV survives longer in liquids than it does when dried on surfaces. They found that in a liquid environment, HCV was detectable for up to five months at lower temperatures.

    - HCV could survive in a liquid medium for two days at 37°C (body temperature), 16 days at 25°C and at least six weeks at 4.4°C (average refrigerator temperature).

    - HCV remained viable in a syringe for up to 63 days. Circumstances that increased HCV infectivity include syringes with detachable needles, lower temperature and larger volume syringes.

    HCV’s ability to live for a prolonged period of time outside the body under the right conditions has extraordinary implications for its transmission. Some of the carriers known to transmit the virus include straws used for nasal drug use, needles used for administering drugs, tattooing, sharing personal care equipment like razors or toothbrushes, certain sexual devices and reuse of medical equipment in healthcare settings. Although we know that it spreads between blood sources, inanimate objects often act as the intermediary to transmit infection. Thus, understanding how long the Hepatitis C Virus can survive outside the body - in all situations - can help guide us toward failsafe practices for reducing the risk of HCV transmission [9].

    2. Concepts of Transmission of Hepatitis C Virus

    2.1 Laboratory diagnosis of Hepatitis C Virus

    Diagnosis of Hepatitis C Virus involves detection and confirmation of the diagnosis of Hepatitis C Virus (HCV) infection and assessment of the severity of liver disease. In addition, evaluation of patients with Hepatitis C should include determination of the patients' suitability for treatment.

    Diagnostic tests for Hepatitis C as shown in (Table 1) can be divided into the following two general categories:

    1-Serological assays that detect antibody to Hepatitis C Virus (anti-HCV)

    2-Molecular assays that detect, quantify, and/or characterize HCV RNA genotypes and subtypes within an infected patient.

    Serological assays have been subdivided into screening tests for anti-HCV, such as the Enzyme Immunoassay (EIA), and supplemental tests such as the Recombinant Immuno Blot Assay (RIBA). Three generations of anti-HCV tests have been developed, and each generation has resulted in an improvement in the sensitivity of detecting anti-HCV Third-generation anti-HCV tests (EIA-3 and RIBA-3, respectively) contain antigens from the HCV core, non- structural 3, nonstructural 4, and nonstructural 5 genes. Detection of HCV RNA in patient specimens by polymerase chain reaction (PCR) provides evidence of active HCV infection and is potentially useful for confirming the diagnosis and monitoring the antiviral response to therapy.

    Currently, the second-generation enzyme immunoassay (EIA-2) for antibodies to HCV (anti-HCV) is the most commonly screening test for HCV infection. The diagnosis of HCV infection can be supported or confirmed by the Recombinant Immunoblot Assay (RIBA) or tests for HCV RNA. Nowadays, the second-generation enzyme immunoassay (EIA-2) for antibodies to HCV (anti-HCV) is the most favorite practical screening test for HCV infection. The diagnosis of HCV by EIA can be supported or confirmed by the Recombinant Immunoblot Assay (RIBA) or tests for HCV RNA. RIBA detects antibodies to individual HCV antigens and confers increased specificity compared to EIA-2. Qualitative Reverse Transcription- Polymerase Chain Reaction (RT-PCR) assays for HCV RNA are simpler than quantitative tests and sufficient for confirmation of the diagnosis of HCV infection.
     

    Type of the Test

    1. Anti-HCV (antibody)

    EIA ( Enzyme Immunoassay)

    Uses:
    Verify if necessary positive EIA with HCV RNA detection Indicates past or present infection, but does not differentiate between acute, chronic or past infection.

    Recombinant Immunoblot Assay (e.g. RIBA™)

    1. HCV RNA (virus)

    Qualitative tests

    Quantitative tests

    PCR – Amplicor HCV™

    PCR - Amplicor HCV Monitor™

    Transcription-Mediated Amplification (TMA) - Versant HCV

    Branched DNA signal amplification – a) Quantiplex™ HCV RNA (bDNA)
    b) Versant HCV RNA Quantitative Assay

     

    Other tests - Super Quant, LCx, real-time PCR…

    TO; Detect presence or absence of virus. Detects virus 1-3 weeks after exposure. Detection of HCV RNA during course of infection may be intermittent. A single negative PCR is not conclusive.

    TO; Determines *titre of HCV. Used to monitor patients on antiviral therapy.

    1. HCV core antigen EIA

    Trak-C

    TO; Detects presence or absence of virus. Detects virus 1-3 weeks after exposure. Under evaluation for the monitoring of patients on antiviral therapy

    1. Genotype

    TO; Groups isolates of HCV into 6 genotypes based on genetic differences.

    With new therapies, length of treatment varies based on genotype.

     
    Table 1: Diagnostic tests for Hepatitis C Virus.
     
    While the vast majority of anti-HCV-positive patients who present with chronic liver disease have ongoing HCV infection as confirmed by the presence of HCV RNA in serum, only 35 percent and 25 percent of anti-HCV-positive blood donors are RIBA-and HCV RNA-positive, respectively. The proportion of anti-HCV-positive blood donors who are confirmed to be HCV RNA-positive varies from 70 percent for those who are RIBA-positive to 2-25 percent for those who are RIBA-indeterminate and none for those who are RIBA-negative. Thus, supplementary and confirmatory tests for HCV infection should always be performed in asymptomatic low-risk subjects who are found to be anti-HCV-positive, particularly if they have normal aminotransferase (ALT) levels; but these tests may not be necessary in all anti-HCV-positive patients who present with chronic liver disease [10].

    Severity of liver disease is best assessed by liver biopsy. There is in general a poor correlation between serum ALT level and activity of liver disease. More importantly, several recent studies found that significant liver disease can be found in anti-HCV-positive patients despite normal ALT levels. These studies reported that 70 percent of RIBA-positive blood donors who had persistently normal ALT levels have chronic Hepatitis or cirrhosis on biopsy. Although most donors (77 percent) who had abnormal liver histology were HCV RNA-positive, significant liver disease was also found in 30 percent of RIBA- positive donors who were HCV RNA- negative and had normal ALT levels on three separate occasions. This may be related to the fluctuating course of chronic HCV infection with intermittently normal ALT levels and undetectable levels of viremia. It may also reflect variations in sensitivities of “home-made” RT-PCR assays for HCV RNA. Liver biopsy should be always recommended except in elderly patients, patients with severe concomitant medical problems, and those with coagulopathy, since neither serum HCV RNA nor ALT level can reliably predict activity or degree of fibrosis. HCV genotyping could be used to monitor the clinical response of HCV therapy, it could only be recommended as a research tool rather than a routine diagnostic test [11].

    2.2 Epidemiology and risk factors of Hepatitis C Virus

    Hepatitis C Virus is one of the most important viral Hepatitis that appears to be endemic in many parts of the world. There are, however, substantial geographic and temporal variations in the incidence and prevalence of HCV infection, largely due to differences in regional risk factors for the transmission of HCV. The overall world prevalence of HCV was estimated to be 3% as an over 170 million person were infected. Such prevalence varies greatly from one country to another and even among the province within the same country. Most of the studies however were based on testing of selected populations such as blood donors [12]. However, population-based surveys are rarely available for most parts of the world. Low rate area (0.1-0.9%) such as Northern Europe to 0.1–0.5% in Western Europe, North America, parts of Central and South America,, intermediate area (1-5%), have been reported from Brazil, Eastern Europe, the Mediterranean area, the Indian subcontinent, and parts of Africa and Asia., High rate area >5% such Arabian peninsula, Africa and the highest prevalence of HCV has been found in Egypt (17–26%) [13,14].

    The major risk factors for HCV infection are blood transfusions from unscreened donors and intravenous drug use as shown in (Figure 2). However, exposure to HCV-infected blood from other health-care-related procedures and regional cultural practices are increasingly recognized as having an important function in HCV transmission in some parts of the world. Since the introduction and improvement in the 1990s of the screening of blood donors, HCV transmission by blood transfusions is now exceedingly rare (around or less than one per million) in developed countries. Unfortunately, the screening of blood donors for HCV is not yet routinely performed by some blood banks in developing countries. Most new cases in developed countries are related to intravenous drug use. Health-care-related procedures leading to nosocomial HCV transmission are not restricted to hemodialysis facilities. Several reports from Western countries have clearly documented nosocomial transmission of HCV through inadvertent sharing of multi-dose vials or unsterilized instruments, among others [15]. Similar nosocomial transmission of HCV outside dialysis units is certainly not less likely to occur in developing countries but has not been reported until now. Additional risk factors for HCV transmission include occupational exposure, especially by accidental needle stick, as well as perinatal transmission (about 6%), whereas the transmission of HCV by sexual activity appears relatively inefficient.

    New social groups are highly prone to HCV these include individual incarceration centers and those with Mental disorders. Different studies found that the sero-prevalence of Hepatitis C Virus among mentally ill patients, approximately 11 times that of the general adult population. Unique risk factors were associated with spread of HCV among these groups include, homelessness , alcohol, drug abuse and risky sexual activities hence then special attention should be directed to such important social groups in order to prevent spread of HCV and comply with the consequences associated with it [16].

    Patients infected with HCV usually confected with Hepatitis B and HIV viruses. The exact number of patients co-infected with HCV and HBV is unknown. In patients with chronic Hepatitis B, estimates of the rates of HCV co-infection vary from 9% to 30%. The primary concern with HBV/HCV co-infection is that it can lead to more severe liver disease and an increased risk for progression to liver cancer (HCC) [2,17]. This is also evident in patients who are HIV-positive are commonly co-infected with HCV. These viruses have shared routes of transmission: percutaneous exposure to blood, sexual intercourse, and from a mother to her infant. Infection with HCV can be asymptomatic, self-limiting, or progress to cirrhosis or cancer.
     
     
    Figure 2: Risk factors associated with Transmission of HCV.
     
    The clinical history of HCV is a unique, usually its mild and rarely patients need a clinical consultation and thus it is usually discovered at the chronic stage. Chronicity rates range from 50 to 90%, with somewhat lower rates in children and young healthy women (50-60%) and higher rates in older individuals and African descents. This however more complicated when the patients co-infected with HIV or HBV.

    3. Transmission of HCV

    HCV is generally transmitted by the parenteral route. Well known and common modes of transmission involve blood transfusions and/or other parenteral contact with blood products. In the developed world, the primary route of transmission is Intravenous Drug Use (IDU), while in the developing countries the main methods are blood transfusions and unsafe medical procedures. However ever, up to 50% of individuals deny exposure to any of these known risk factors, and infection is often designated as “community acquired,” though strong believe suggest these could be accounted for by IDU.

    3.1 Blood transfusion-transmission

    Before the initiation of HCV antibody screening, approximately 10% to 20% of individuals, who had received multiple blood transfusions or plasma products sero-converted to anti-HCV positive. Thus, the relative risk was 0.45% per unit transfused. However, the introduction of routine HCV antibody screening of blood products has led to a sharp decrease in the transmission rate of HCV. For example, the risk of acquiring antibodies to HCV by blood transfusions using current screening procedures was calculated as 1/100,000 units transfused. This remaining low risk is believed to be principally caused by blood’s susceptibility to infection just after acquisition of HCV infection and before the appearance of anti-HCV antibodies. Therefore, the detection of HCV RNA by RT-PCR would potentially allow for the identification of such infectious units, although this technique is not in routine use for screening blood donor population [18].

    Retrospective studies of blood donor and recipient repositories from the mid 1960’s and early 1970’s demonstrated that almost 25% of recipients were infected with HCV several events in the 70’s and 80's, such as moving to volunteer blood donation, implementation of screening and exclusion of Hepatitis B surface antigen (HBsAg) positive blood, allowed for a significant reduction in Transfusion-Transmission of HCV (TT HCV). In addition, in the early 1980’s the recognition of TT HIV led to more stringent exclusion criteria for blood donations and a reduction in TT HCV.

    Nowadays the current risk of TT HCV in developed countries is 1 in a million (0.0001%) per unit transfused. In developing countries such Indian-subcontinent, China, South-East Asia and Africa the situation is still ambitious, and transfusion transmission of HCV is still a leading mode of transmission among these countries as illustrated in (Figure 3). This is particularly due lack of adapting the safety standard regulations among blood banks. These may include; policies and systems that encourage t blood donation by volunteers have not been successfully implemented; lack basic blood banking practices, lack of standardization and adapting modern blood testing and adding newly needed tests such as NAT testing. Therefore, policies are urged to prevent TT HCV among these countries and the experiences of the developed countries have to be mirrored At the time of identification and deferral, blood donors may be notified of their HCV status, including RNA and antibody confirmatory test results that may help HCV infected individuals to receive timely therapy to deter disease progression [20]. In the era of new and potent antiviral agents against HCV, timely intervention can help prevent future public health burden associated with HCV-related liver diseases.
     
     
    Figure 3: Geo-epidemiology of HCV transfusion-transmission worldwide.
     
    3.2 Intravenous Drug Users (IDUs)

    Injection drug use is known to play a major role in HCV transmission and there has been an emerging epidemic of Hepatitis C Virus (HCV) infection among Injection Drug Users (IDU) - particularly among developed countries. Injection Drug Users (IDUs) account for a disproportionately large burden of Hepatitis C Infection. Ninety percent of new infections worldwide (∼90% in Australia, ∼72% in Canada, and ∼54% in the United States) are contracted through injection drug use, and the majority of chronic infections, particularly in developed countries, are attributed to injection drug use In Injecting Drug Users (IDUs) population there has been increased shifts among addicts from inhalatory to injectable drugs due decrease in quality and availability of heroin. Further, the effect of injecting drugs is more intense and satisfying as HCV is found in a high concentration in spoons and rinsing liquids that could be used in association with needle drug use [21].

    A variety of variables has to be considered when differentiating risk for these infections within injecting drug users. These include the duration of injection drug use as the prevalence of infection increases with longer duration of injection drug use which reflects the effect of cumulative exposure and thus the higher rate of HCV transmission among IUDs. More recent initiates into injection drug use have higher rates of new infection compared with more experienced drug users. This highlights the importance of targeting preventive interventions early for them to be most effective as there is increased risk among newer injectors

    Despite advancements in the management of chronic Hepatitis C and suggestions that treatment of recently acquired Hepatitis C can lead to Sustained Virological Response (SVR) rates of up to 98%,there continues to be a low rate of treatment uptake among current IDUs [22]. Studies conducted in IDU populations in developed countries suggest that very few IDUs infected with Hepatitis C Virus have received antiviral therapy. The continuing reluctance to treat IDUs is driven by concerns about the risk of reinfection, high rates of concomitant alcohol abuse, and high rates of concomitant mental health issues, all potentially impacting treatment compliance and effectiveness

    A variety of measures which should be taken may include;

    - Create community-led education and messaging strategies on Hepatitis C risks, injection transmission risks (e.g., sharing drug preparation equipment in addition to sharing drug injection equipment), and HCV testing resources.

    -Improve and increase infrastructure for HCV surveillance and data collection

    - Create age-appropriate (e.g., young adult) substance use and Hepatitis C interventions and prevention strategies that are evidence based and effective

    - Expand both community-based and basic science research activities to better understand how to effectively address the emerging crisis of Hepatitis C Infection among young IDUs

    3.3Contaminated needles

    HCV is transmitted by contaminated needles. The rate of transmission probably depends, in part, on the quantity of blood transferred to the recipient by the needle stick, the titer of virus, and the depth of inoculation. Approximately 2% of exposed individuals will develop viremia and/or anti-HCV antibodies after needle stick exposure. The rate of HCV infection after sticks with solid needles appears to be lower as compared with accidents with hollow cannula devices. The risk of acquiring Hepatitis C by needle-stick injury ranging from 3 to 10.3%, comparable to HBV risk= 5 - 40%and HIV risk = 02 - 0.5 %.The prevalence of anti-HCV in health workers does not differ significantly from blood donors. However, viremia can be detected very rapidly (within an hour) in exposed personnel without this leading to persistent infection while sero conversion to anti-HCV can occur very late. Epidemiologic studies of HCV have indicated that transmission among patients in health care settings is associated with contaminated vehicles such as multi-dose medication vials and re-used needles and syringes and among injecting drug users is associated with contaminated drug paraphernalia such as cookers and cotton [23,7].

    3.4 Sexual transmission

    Sexual transmission of HCV infection has been demonstrated but is less frequent compared with Hepatitis B. Studies in the United States and Europe have revealed low rates of exposure (0%-6.3%) in heterosexual partners of individuals with chronic HCV infection. Interestingly, recent reports from Asian countries have found higher positivity rates of 7.3% to 27.5%.It is noteworthy that HCV RNA has not generally been found in semen, vaginal fluid, urine, stools and Saliva. Antibodies to HCV have been found in 1% to 12% of prostitutes, an increase of the HCV antibody positivity rate from 4% to 9% has been described in heterosexual partners if there is co-infection with HIV [24]. It appears however, that the prevalence of HCV antibodies in sexual partners of heterosexual and homosexual relationships is similar.

    While Hepatitis C is not classified as an (Sexual Transmitted Infection) STI, there is a risk of Hepatitis C transmission if the blood of one person enters the bloodstream of another person during sexual intercourse. Men who have sex with men and who also have HIV have a higher proportion of Hepatitis C transmission through sexual exposure compared to all people with the Hepatitis C infection.

    3.5 Nosocomial acquisition of HCV

    Hepatitis C Virus has been known to be an important nosocomial pathogen, and several outbreaks have been linked to breaches in standard precautions for blood-borne infections during nursing procedures or interventions such as colonoscopy surgery and dialysis. Hepatitis C Infection is commonly associated with patients with hemodialysis particularly among developing countries health care settings. HCV prevalence in HD varies geographically, both within and between countries. The prevalence of HCV antibodies ranged between 8% to 80%.A number of risk factors have been identified for HCV infection among dialysis patients, including the number of blood transfusions, the duration of ESRD, the mode of dialysis, and the prevalence of HCV infection in the dialysis unit. The risk of HCV infection appears to correlate with the duration and frequency of hemodialysis [25]. A variety of other nosocomial factors may affect the risk of transmission of HCV to patients and staff in dialysis units.

    -Transmission of HCV from infected patient to dialysis staff by needle-stick injury
    -Breakdown in standard infection control practices
    -Physical proximity to an infected patient
    -Dialysis machines
    -Dialyzer membranes, hemodialysis ultra-filtrate, and peritoneal fluid
    -Reprocessing of dialyzers


    A variety prophylactic measures have been suggested to avoid infection by HCV in the hemodialysis environment, and range from isolating patients with HCV infection to adopting a series of biosafety measures specific for HD, such as preparing medications in a separate area, cleaning and disinfecting dialysis station surfaces, washing hands and changing gloves between patient contacts, and items dedicated for use only with a single patient. Strict adherence to universal infection control precautions seems to be enough to control the spread of disease in HD units.

    3.6 Habitual and community-Associated factors

    Community has been considered to be an important source for Hepatitis C, and up to 50% of individuals deny exposure to any of these known risk factors where, infection is often designated as community. Persons incarcerated in correctional systems comprise a certain proportion among population and have a disproportionately greater burden of infectious diseases, including infections with Hepatitis Viruses and other infections of public health importance. As most of inmates of prisons and jails were released and returned to the community [1,24].

    Within the community incarcerated populations are particularly at a higher risk of HCV infection. Among adult prison inmates, 16%-41% have serologic evidence of HCV infection, and 12%-35% have chronic HCV infection; rates vary by geographic region. Though prevalence of HCV antibody among detained or incarcerated juveniles is estimated at 2%-3.5%, approximately 12% of persons aged 16 years reported at least one arrest in their lifetimes. Upon incarceration, all adults and the majority of juveniles lose access to the usual public and private health-care and disease-prevention services. Their health care becomes the sole responsibility of either the correctional system or less frequently, the public health system. In some countries entry into the correctional system provides an opportunity to access health care.

    3.7 Vertical transmission of Hepatitis C Virus

    Compared with adults, infection in children is much less well understood. Worldwide the prevalence of Hepatitis C Virus infection in pregnant women and children has been estimated to 1-8% and 0.05-5% respectively. The vertical transmission rate has been estimated to be 3-5% and there is a high rate of spontaneous clearance (25-50%) in the children. Higher rates have been reported for both vertical transmission (18%, 6-36% and 41%) and prevalence in children (15%).

    In developed countries perinatal transmission is now the leading mechanism of HCV transmission. In the absence of virus in the mother's blood transmission seems to be rare. Factors associated with an increased rate of perinatal infection include membrane rupture of longer than 6 hours before delivery and procedures exposing the infant to maternal blood. Cesarean sections are not recommended. Breast feeding is considered safe if the nipples are not damaged. Perinatal infection of a child does not increase the risk in a subsequent pregnancy. All genotypes appear to have the same risk of transmission.HCV infection is frequently found in children who have previously been presumed to have non-A, non-B Hepatitis and cryptogenic liver disease. The presentation in childhood may be asymptomatic or with elevated liver function tests. While infection is commonly asymptomatic both cirrhosis with liver failure and hepatocellular carcinoma may occur in childhood.

    4. Prevention of Hepatitis C Virus Transmission

    Understanding the modes of Transmission of HCV and the ways it spreads among communities and heath care settings, plays important steps in formulating the strategies of prevention of such infectious virus. Hepatitis C transmission is preventable [26]. Effective prevention interventions reduce transmission and the subsequent impact of infection on individuals and the community. Reducing HCV transmission minimizes greatly morbidity and mortality caused by, Hepatitis C and to minimize the personal and social impact of the disease. Although the priorities of such strategies may vary from one country to another and even among health care centers themselves. Immediate and long run strategies should be implemented targeting both the community and health care settings. (Table 2) illustrates the most of these strategies [15]. However, special emerging programs should be highlighted these include.
     
    1. Immediate continuous prevention strategies
    a) Universal prevention planning
    (i) Well-planned educational programs regarding the risk of HCV both at the community and health institutions levels.
    (ii) Implementation of international and national guidelines regarding the prevention of HCV particularly at special hospital settings as blood banks and hemodialysis units and high risk groups at the community.
    (iii) Strict adherence to such guidelines and regular assessment to its applications.
    (iv) Introducing specific patient-care practices.
    b) Special settings prevention programs
    (i) Blood and blood products, HCV screening program and using thioproprin, haemovigilance.
    (ii) Hemodialysis; strict adherence to nosocomial prevention program; review practices to ensure they are consistent with recommendations and applied routinely,
    (iii) Laboratory and health care; improving laboratory testing, better sterilization, safer injection, and less exposure to blood products.
    2. Long-run preventive strategies
    a) Universal preventive planning
    (i) Vigilance and health alert programs which should report any problem and allow to interfere at any time.
    (ii) Elucidation is needed for better prevention, screening, and updating HCV treatment
    (iii) Prevention of HCV infection progress
    (iv) Eradicate the massive use of unsafe medical procedures
    b) Special settings preventive planning
    (i) Injecting drug users
    (ii) HIV-HCV co-infected patients
    (iii) Prisoners inmates
    (IV) Patients with Mental Disorders
    3. Research planning and priorities
    Well-designed research programs should be established both at country level and regional levels which may include.
    (i) Population-based surveillance studies.
    (ii) Evaluation of safety and efficacy of antiviral therapy for HCV alone and with other co-infected viruses particularly HIV.
    (iii) Further evaluation of iatrogenic causes of HCV.
     
    Table 2: Preventive and combat strategy programs for Hepatitis C Virus.
     
    4.1Blood banking services

    Despite the great scientific progress that has been achieved in preventing transmission of HCV among blood banking services as blood has been considered to be very safe nowadays such burden still exist. Improved blood banking practices and the development and implementation of increasingly sensitive serological and nucleic acid amplification technology assays for screening donors for HCV over the past few decades have helped minimize the residual risk from transfusion transmitted HCV in the developed world [25,27].

    Transfusion-transmission of HCV continues to be a problem particularly among developing nation. This however, may be related to many factors among these countries such as infrastructure, cultural and behavioral circumstances, human resources, political structure and economy. These countries should introduce key preventive mechanisms to ensure safe blood include elimination of paid donors and development of national donor pools comprising volunteer repeat blood donors, combined with implementation of standardized and maximally sensitive screening assays for HCV.

    4.2 Hospital care settings

    Nosocomial transmission of HCV particularly among hemodialysis still poses the main burden on health services worldwide. The nosocomial type of transmission was probably the dominant means of HCV spread in the dialysis unit. We would advocate strict enforcement of the universal measures for infection control, and assignment of patients to different dialysis machines, depending on their viral marker positivity. The incidence and prevalence of HCV infection among dialysis patients is steadily declining. The decline was initially due to the reduction in post-transfusion HCV infections, subsequently, it has reflected the implementation of infection-control measures to prevent nosocomial transmission within dialysis units. In developing countries medical-related transmission of HCV, such as hospitalization and/or surgical and dental procedure still accounted for a higher risk among hospital care setting, hence then adhering to universal precautions within healthcare facilities becomes priority. Further, more lack of insufficient supply of sterile syringes, dictates that medications should be given orally rather than via injection (when possible).

    4.3 Community prevention programs

    HCV is considered to a dynamic disease particularly among young people within the community. Hence then education and social programs should be introduced and special care centers has to be established particularly for IUDs and individuals with Mental disorders. These groups are particularly at a higher risk of HCV, due to poverty, literacy, homelessness, ignorance, multiple sex partners and despair. Furthermore, they have less access to health care services within the societies. Strengthening the capacity of education providers and the providers of services to young people to ensure they have access to harm. Enhance training and support for community based Hepatitis C educators, including injecting drug user peer educators’ reduction knowledge and skills.

    4.4 Post exposure prophylaxis for Hepatitis C Virus infection

    At the moment there is no proved effective post exposure prophylaxis to HCV and no clear evidence for using immunoglobulin and ant-viral agents despite the ongoing clinical trials for using such antiviral agents. This however adds a further burden on the prevention programs for HCV particularly among health care workers, hence then particular attention should be taken regarding education and preventive methods to HCV. Therefore, implementing primary preventive strategies should be the corner stone for any program this include behavior modification both in community and health care settings. Awareness of the existing risk of acquiring HCV, education and training the involved personnel to implement the universal standard precautions avoid exposure to HCV [27]. However, (Figure4) highlights the management of exposure to Hepatitis C infection this includes performing the testing for anti-HCV antibodies and liver enzymes as shown in (Table 1).
     
     
    Figure 4: Diagnosis and management of post exposure to Hepatitis C infection.
     
    5. Conclusions and Recommendations

    There is an urgent need to better understand HCV prevalence and incidence rates in different countries around the world to help curb transmission from preventable causes, and especially through blood transfusion. Blood transfusion and other parenteral exposures in health care settings are still major routes of HCV transmission among individuals in developing countries compared to the rest of the world where the major route of transmission is currently IDU. Further tight global cooperation is particularly needed to make the blood more safe among developing countries. As studies of transfusion transmitted infections and of donors identified as infected by routine screening have provided significant insights into HCV transmission, epidemiology and pathogenesis. There is also a need to develop up-to-date data on HCV disease burden on a global scale, in part, derived from systematic screening of donors for HCV infection. Furthermore, a creation of blood donor databases and specimen repositories, both at national and international levels, to facilitate epidemiological surveillance and pathogenesis and treatment studies in the future may be needed. Strict adherence to a nosocomial prevention programs among health care center, screening and isolation of patients at risk if needed. A combination of harm reduction strategies, such as the provision of new needles and syringes and treatment of substance use, decrease the risk of Hepatitis C in intravenous drug users by about 75% among communities. Hepatitis C surveillance systems need to be developed and enhanced to provide accurate data to inform the planning and delivery of prevention and disease management options.

    Workforce development is critical for minimizing the impact of Hepatitis Con individuals and the community as a whole. Easy access to information about transmission, testing, treatment and referral through a broad range of professionals underpins the majority of the priority action areas. Clinical, prevention and community services and organizations which support people with Hepatitis C need to be adequately resourced and informed to deliver appropriate services to people with Hepatitis C. Specific support should also be provided to peer-education and support services. Improving research activities that could solely contribute to reducing the impact of Hepatitis C on the community and understanding of Hepatitis C, including the economic impact of actions and inactions. These should be clearly linked to the needs of affected communities and identify methods of overcoming the barriers to prevention, testing, diagnosis, treatment and management of Hepatitis C, including identifying preferred models of care. Future concepts may include vaccination though, no vaccine protects against contracting Hepatitis C yet. However, a number are under development and some have shown encouraging results.
     
     
    References
     



























     
     
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