Outbreak of hepatitis C virus infection in a hemodialysis unit: potential transmission by the hemodialysis machine?

Updated Evidence on the Epidemiology of Hepatitis C Virus in Hemodialysis

Prevalence rates of HCV infection are decreasing in hemodialysis units of most developed countries; however, nosocomial transmission of HCV continues to occur in the hemodialysis setting, not only in the emerging world. According to the Dialysis Outcomes and Practice Patterns Study (DOPPS, 2012–2015), the prevalence of HCV among patients on regular hemodialysis was 9.9%; in incident patients, the frequency of HCV was approximately 5%. Outbreaks of HCV have been investigated by epidemiologic and phylogenetic data obtained by sequencing of the HCV genome; no single factor was retrieved as being associated with nosocomial transmission of HCV within hemodialysis units. Transmission of HCV within HD units can be prevented successfully by full compliance with infection control practices; also, antiviral treatment and serologic screening for anti-HCV can be useful in achieving this aim. Infection control practices in hemodialysis units include barrier precautions to prevent exposure to blood-borne pathogens and other procedures specific to the hemodialysis environment. Isolating HCV-infected hemodialysis patients or using dedicated dialysis machines for HCV-infected patients are not currently recommended; reuse of dialyzers of HCV-infected patients should be made, according to recent guidelines. Randomized controlled trials regarding the impact of isolation on the risk of transmission of HCV to hemodialysis patients have not been published to date. At least two studies showed complete elimination of de novo HCV within HD units by implementation of strict infection control practices without isolation practices. De novo HCV within hemodialysis units has been independently associated with facility HCV prevalence, dialysis vintage, and low staff-to-patient ratio. Antiviral treatment of HCV-infected patients on hemodialysis should not replace the implementation of barrier precautions and other routine hemodialysis unit procedures.

Clinical practice guideline management of blood borne viruses within the haemodialysis unit

Some people who are receiving dialysis treatment have virus infection such as hepatitis B, hepatitis C and/or HIV that is present in their blood. These infections can be transmitted to other patients if blood is contaminated by the blood of another with a viral infection. Haemodialysis is performed by passing blood from a patient through a dialysis machine, and multiple patients receive dialysis within a dialysis unit. Therefore, there is a risk that these viruses may be transmitted around the dialysis session. This documents sets out recommendations for minimising this risk.There are sections describing how machines and equipment should be cleaned between patients. There are also recommendations for dialysing patients with hepatitis B away from patients who do not have hepatitis B. Patients should be immunised against hepatitis B, ideally before starting dialysis if this is possible. There are guidelines on how and when to do this, for checking whether immunisation is effective, and for administering booster doses of vaccine. Finally there is a section on the measures that should be taken if a patient receiving dialysis is identified as having a new infection of hepatitis B, hepatitis C or HIV.

Hepatitis C virus transmission in a Dutch haemodialysis unit: detailed outbreak investigation using NS5A gene sequencing

BACKGROUND

Haemodialysis is a risk factor for hepatitis C virus (HCV) transmission. Two patients receiving haemodialysis in a Dutch dialysis unit in The Hague were found to seroconvert to HCV in December 2016 after the yearly routine control for blood-borne viruses. Following the presumed time of infection, three chronically infected HCV patients were identified as possible index cases.

AIM

To confirm inter-patient transmission and to identify the source.

METHODS

Molecular investigation and review of medical records were performed.

FINDINGS

Both of the incident cases and one of the three possible index cases were demonstrated to be infected with HCV genotype 2b based on 5'UTR sequencing. Epidemiological relatedness between these viruses was further investigated by sequencing of the NS5A region. Phylogenetic analysis clearly identified the incident cases and the index case to represent a cluster distinct from unrelated controls with HCV genotype 2b. Detailed review of the medical records identified two possible incidents that might have resulted in the HCV transmission cases: contamination of the venous pressure-sensing port due to high venous pressures or incomplete compliance with infection control precautions of the unit staff during handling of two incidents, that occurred at the same time in a single haemodialysis session with the index patient as well as both incident cases present.

CONCLUSION

This study demonstrates that detailed incident recording in combination with state-of-the-art molecular investigations such as sequencing of the NS5A region resulted in unravelling a set of two HCV transmissions that occurred at a haemodialysis unit.

Dangerous practices in a hemodialysis unit in Vietnam identify from mixed methods

BACKGROUND

Non-compliance with infection control practices poses a serious risk to patients receiving chronic hemodialysis. We aimed to identify the type and frequency of non-compliance with infection control practices in a hemodialysis unit in Vietnam where a large outbreak of hepatitis C infection had occurred.

METHODS

Mixed methods approach included observations and discussions of non-compliance with all 12 nurses at the Hemodialysis Unit, District-6 Hospital in Ho Chi Minh City. Observations of nursing care activities were made between September 2013 and January 2014. Compliance with hand hygiene and glove use during nursing care activities were classified according to the potential for a serious risk of transmission of infection and reported as percentages. Each nurse was expected to provide 11 nursing care activities to three patients assigned per hemodialysis sessions. Activities were to be given on an individual patient-centered care basis, that is, one patient was to receive all 11 activities by their assigned nurse. On completion of the observations all nurses were enrolled in a focus group where observed non-compliance was discussed and transcripts were examined for themes.

RESULTS

Hand hygiene compliance rate was low (27%, 95%CI 25%-28%, 1633/6140) regardless of classification of seriousness of risk from this breach. Although glove use (76%, 95%CI 74-78%, 1211/1586) and other personal protective equipment use (81%, 95%CI 78%-83%, 773/959) were high gloves were observed to be reused with multiple patients during a single nursing care activity provided to consecutive patients. Nurses explained the breakdown of providing nursing care activities on an individual patient-centered basis was a response to limited supply of gloves and hand hygiene facilities and was exacerbated by nursing being co-opted by overly demanding patients to provide services without delay.

CONCLUSIONS

The adaption by the nurses to provide 11 single care activities to multiple consecutive patients in the absence of changing gloves and low hand hygiene compliance was potentially the central risk factor that facilitated the hepatitis C outbreak. Patient-centered care needs to be enforced to minimize multiple nurse-patient contacts that are associated with non-compliance classified as serious risk of infection transmission. Nurse empowerment to resist unreasonable patient demands may also be pivotal to assisting their compliance with hand hygiene and single patient-centered care. An audit program to measure infection control resources and practices may facilitate enforcement of the guidelines.

Patient-to-Patient Transmission of Hepatitis C Virus Through the Use of Multidose Vials During General Anesthesia

A duster of four patients with hepatitis C virus (HCV) infection was identified in a surgery clinic. Molecular characterization revealed close homology between viruses. This cluster was related to unsafe injection practices through multidose vials and reused materials. Among 796 patients potentially exposed to and screened for HCV, no other cluster was identified.

A Large Nosocomial Outbreak of Hepatitis C Virus Infections at a Hemodialysis Center

Objective:

To identify modes of HCV transmission during an outbreak of HCV infection in a hemodialysis unit.

Design:

An epidemiologic study, virologie analysis, assessment of infection control practices and procedures, and technical examination of products and dialysis machines.

Setting:

A private hemodialysis unit treating approximately 70 patients.

Patients:

Detection of HCV RNA by PCR was performed among patients receiving dialysis in 2001. Case-patients were patients who had a first positive result for HCV RNA between January 2001 and January 2002 and either acute hepatitis, a seroconversion for HCV antibodies, or a previous negative result. Three control-patients were randomly selected per case-patient.

Results:

Of the 61 patients treated in the unit in 2001 and not infected with HCV, 22 (36.1%) became case-patients with onset from May 2001 to January 2002 for an incidence density rate of 70 per 100 patient-years. Phylogenic analysis identified four distinct HCV groups and an index case-patient for each with a similar virus among patients already known to be infected. No multidose medication vials or material was shared between patients. Connection to a dialysis machine by a nurse who had connected an HCV-infected patient “just before” or “one patient before” increased the risk of HCV infection, whereas using the same dialysis machine after a patient infected with HCV did not. Understating, lack of training, and breaches in infection control were documented. Direct observation of practices revealed frequent flooding of blood into the double filter on the arterial pressure tubing set.

Conclusions:

During this outbreak, HCV transmission was mainly patient to patient via healthcare workers' hands. However, transmission via dialysis machines because of possible contamination of internal components could not be excluded.

Viral hepatitis in hemodialysis: An update

Hepatitis outbreaks in hemodialysis (HD) patients and staff were reported in the late 1960s, and a number of hepatotropic viruses transmitted by blood and other body fluids have been identified. Hepatitis B virus (HBV) was the first significant hepatotropic virus to be identified in HD centers. HBV infection has been effectively controlled by active vaccination, screening of blood donors, the use of erythropoietin and segregation of HBV carriers. Hepatitis delta virus is a defective virus that can only infect HBV-positive individuals. Hepatitis C virus (HCV) is the most significant cause of non-A, non-B hepatitis and is mainly transmitted by blood transfusion. The introduction in 1990 of routine screening of blood donors for HCV contributed significantly to the control of HCV transmission. An effective HCV vaccine remains an unsolved challenge; however, pegylation of interferon-alfa has made it possible to treat HCV-positive dialysis patients. Unexplained sporadic outbreaks of hepatitis by the mid-1990s prompted the discovery of hepatitis G virus, hepatitis GB virus C and the TT virus. The vigilant observation of guidelines on universal precaution and regular virologic testing are the cornerstones of the effective control of chronic hepatitis in the setting of HD. Major recent advances in the viral diagnosis technology and the development of new oral, direct-acting antiviral agents allow early diagnosis and better therapeutic response. The current update will review the recent developments, controversies and new treatment of viral hepatitis in HD patients.

Transmission of Hepatitis C Virus Between Hemodialysis Patients Sharing the Same Machine

After a patient acquired hepatitis C virus (HCV) infection in our unit, we performed epidemiologic and virologic investigations, including genotyping and phylogenetic analyses. The results provided evidence for HCV transmission between two patients sharing the same machine and suggested possible transmission via accidental contamination of the venous pressure monitoring system.

Hepatitis C Virus Transmission From a Healthcare Worker to a Patient

We investigated the source of infection in a patient who developed acute hepatitis C virus infection after cardiothoracic surgery. A healthcare worker was found to be infected with hepatitis C virus, and molecular analysis indicated the strain was similar to that found in the patient. The exact mode of transmission was not identified; however, atopic eczema on the healthcare worker's hands may have contributed to the transmission.

HIV transmission at a Saudi Arabia hemodialysis unit

This study confirms the occurrence of hemodialysis-associated HIV infection. The occurrence of such transmission is linked to the suboptimal compliance with prevention and control of infection measures.

Background. Hemodialysis is associated with increased risk of healthcare-associated infections but considered a low-risk setting for human immunodeficiency virus (HIV) transmission. We investigated 3 hemodialysis unit (HDU) patients with new HIV infections to determine whether transmission was hemodialysis-associated and to correct factors that contributed to transmission.

Methods. Each patient was evaluated for HIV risk factors. Blood samples were tested to determine relatedness of HIV strains. Clinical data (gathered over 18 months) was reviewed to identify seroconversions at 12 HDUs. Infection prevention and control practices were evaluated at 14 HDUs.

Findings. No other HIV seroconversions were identified during the study. HIV gag, pol, and env gene sequences were consistent with a clonal relationship. HIV and hepatitis C virus prevalence rates at one HDU 1 (5.7% and 6.5%, respectively) were higher than for 11 other HDUs (0% and 0.15%, respectively).

Conclusions. Sequencing supports either patient-to-patient or common-source transmission. Infections occurred despite Saudi Arabia's low HIV prevalence and national dialysis policies that emphasize stringent infection prevention and control practices.

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.

Conclusion

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.

Profile of hepatitis B virus, hepatitis C virus, hepatitis d virus and human immunodeficiency virus infections in hemodialysis patients of a tertiary care hospital in uttarakhand

BACKGROUND AND AIM

Viral hepatitis and human immunodeficiency virus (HIV) infection are important causes of morbidity and mortality in hemodialysis (HD) patients. The present study was performed to assess the prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV) and HIV infections in hemodialysis patients of a tertiary care hospital in Uttarakhand.

METHODS

All patients undergoing maintenance HD at our center were screened for hepatitis B surface antigen (HBsAg), antibody to HCV (anti-HCV), antibody to HDV (anti-HDV) and HIV antibody by ELISA. Detailed history regarding age, sex, duration of dialysis, blood transfusions, number of dialysis centers, dialyzer reuse and laboratory data was recorded.

RESULTS

A total of 118 patients (79 males and 39 females) were followed for 18 months with screening for the presence of HBV, HCV and HIV infections. At baseline, 12 (10.2%) patients were positive for HBsAg, 19 (16.1%) for anti-HCV and 2 (1.7%) for HIV antibody. Over 18 months, one additional patient became HBsAg positive and an additional 17 became anti-HCV-positive to give a total of 36 HCV-positive patients. Dual HBV and HCV infection was seen in 5 (4.2%) and anti-HDV antibodies were found in 1 (0.9%) patient. History of blood transfusions, duration of HD, dialyzer reuse and dialysis at multiple centers were found to be important risk factors for anti-HCV positivity.

CONCLUSIONS

Implementation and adherence to universal work precautions by dialysis staff is imperative to prevent transmission of these infections.

Healthcare workers and prevention of hepatitis C virus transmission: exploring knowledge, attitudes and evidence-based practices in hemodialysis units in Italy

BACKGROUND

Evidence exists regarding the full prevention of HCV transmission to hemodialysis patients by implementing universal precaution. However, little information is available regarding the frequency with which hospitals have adopted evidence-based practices for preventing HCV infection among hemodialysis patients. A cross-sectional survey has been conducted among nurses in Calabria region (Italy) in order to acquire information about the level of knowledge, the attitudes and the frequencies of evidence-based practices that prevent hospital transmission of HCV.

METHODS

All 37 hemodialysis units (HDU) of Calabria were included in the study and all nurses were invited to participate in the study and to fill in a self-administered questionnaire.

RESULTS

90% of the nurses working in HDU participated in the study. Correct answers about HCV pattern of transmission ranged from 73.7% to 99.3% and were significantly higher in respondents who knew that isolation of HCV-infected patients is not recommended and among those who knew that previous bloodstream infections should be included in medical record and among nurses with fewer years of practice. Most correctly thought that evidence-based infection control measures provide adequate protection against transmission of bloodborne pathogens among healthcare workers. Positive attitude was significantly higher among more knowledgeable nurses. Self-reporting of appropriate handwashing procedures were significantly more likely in nurses who were aware that transmission of bloodborne pathogens among healthcare workers may be prevented through adoption of evidence-based practices and with a correct knowledge about HCV transmission patterns.

CONCLUSIONS

Behavior changes should be aimed at abandoning outdated practices and adopting and maintaining evidence-based practices. Initiatives focused at enabling and reinforcing adherence to effective prevention practices among nurses in HDU are strongly needed.

High false-negative rate of anti-HCV among Egyptian patients on regular hemodialysis

Routine serological testing for hepatitis C virus (HCV) infection among hemodialysis (HD) patients is currently recommended. A dilemma existed on the value of serology because some investigators reported a high rate of false-negative serologic testing. In this study, we aimed to detect the false-negative rate of anti-HCV among Egyptian HD patients. Seventy-eight HD patients, negative for anti-HCV, anti-HIV, and hepatitis B surface antigen, were tested for HCV RNA by reverse transcriptase polymerase chain reaction (RT-PCR). In the next step, the viral load was quantified by real-time PCR in RT-PCR-positive patients. Risk factors for HCV infection, as well as clinical and biochemical indicators of liver disease, were compared between false-negative and true-negative anti-HCV HD patients. The frequency of false-negative anti-HCV was 17.9%. Frequency of blood transfusion, duration of HD, dialysis at multiple centers, and diabetes mellitus were not identified as risk factors for HCV infection. The frequency of false-negative results had a linear relation to the prevalence of HCV infection in the HD units. Timely identification of HCV within dialysis units is needed in order to lower the risk of HCV spread within the HD units. The high false-negative rate of anti-HCV among HD patients in our study justifies testing of a large scale of patients for precious assessment of effectiveness of nucleic acid amplification technology testing in screening HD patient.

Prevalence and incidence of hepatitis C virus in hemodialysis patients in British Columbia: Follow-up after a possible breach in hemodialysis machines

BACKGROUND

A possible breach of the transducer protector in specific dialysis machines was reported in June 2004 in British Columbia (BC), which led to testing of hemodialysis patients for hepatitis C virus (HCV), hepatitis B virus (HBV) and HIV. This testing provided an opportunity to examine HCV incidence, prevalence and coinfection with HBV and HIV, and to compare anti-HCV and HCV polymerase chain reaction (PCR).

METHODS

The results of hemodialysis patients who were dialyzed on the implicated machines (65% of BC dialysis patients), and tested for HCV, HBV and HIV, between June 1, 2004, and December 31, 2004, were reviewed and compared with available previous results.

RESULTS

Of 1286 hemodialysis patients with anti-HCV and/or HCV-PCR testing, 69 (5.4%) tested positive. Two HCV genotype 4 seroconversions were identified. HCV incidence rate on dialysis was 78.8 cases per 100,000 person-years. Younger age, history of renal transplant and past HBV infection were associated with HCV infection. No occult infection was identified using HCV-PCR.

INTERPRETATION

Hemodialysis patients had three times the HCV prevalence rate of the general BC population, and more than 20 times the incident rate of the general Canadian population. One of the two seroconversions occurred before the testing campaign; the patient was likely infected during hemodialysis in South Asia. The other was plausibly a late seroconversion following renal transplant in South Asia. Nosocomial transmission cannot be ruled out because both patients were dialyzed in the same centre. Baseline and annual anti-HCV testing is recommended. HCV-PCR should be considered at baseline for persons with HCV risk factors, and for returning travellers who received dialysis in HCV-endemic countries to identify HCV infection occurring outside the hemodialysis unit.

Patient-care practices associated with an increased prevalence of hepatitis C virus infection among chronic hemodialysis patients

OBJECTIVE

To identify patient-care practices related to an increased prevalence of hepatitis C virus (HCV) infection among chronic hemodialysis patients.

DESIGN

Survey.

SETTING

Chronic hemodialysis facilities in the United States.

PARTICIPANTS

Equal-probability 2-stage cluster sampling was used to select 87 facilities from all Medicare-approved providers treating 30-150 patients; 53 facilities and 2,933 of 3,680 eligible patients agreed to participate.

METHODS

Patients were tested for HCV antibody and HCV RNA. Data on patient-care practices were collected using direct observation.

RESULTS

The overall prevalence of HCV infection was 9.9% (95% confidence interval [CI], 8.2%-11.6%); only 2 of 294 HCV-positive patients were detected solely by HCV RNA testing. After adjusting for non-dialysis-related HCV risk factors, patient-care practices independently associated with a higher prevalence of HCV infection included reusing priming receptacles without disinfection (odds ratio [OR], 2.3 [95% CI, 1.4-3.9]), handling blood specimens adjacent to medications and clean supplies (OR, 2.2 [95% CI, 1.3-3.6]), and using mobile carts to deliver injectable medications (OR, 1.7 [95% CI, 1.0-2.8]). Independently related facility covariates were at least 10% patient HCV infection prevalence (OR, 3.0 [95% CI, 1.8-5.2]), patient-to-staff ratio of at least 7 : 1 (OR, 2.4 [95% CI, 1.4-4.1]), and treatment duration of at least 2 years (OR, 2.4 [95% CI, 1.3-4.4]).

CONCLUSIONS

This study provides the first epidemiologic evidence of associations between specific patient-care practices and higher HCV infection prevalence among hemodialysis patients. Staff should review practices to ensure that hemodialysis-specific infection control practices are being implemented, especially handling clean and contaminated items in separate areas, reusing items only if disinfected, and prohibiting mobile medication and clean supply carts within treatment areas.

Decreased prevalence and incidence of HCV markers in haemodialysis units: a multicentric French survey

BACKGROUND

A variety of epidemiological data provide evidence for the nosocomial transmission of hepatitis C virus (HCV) infections to haemodialysis patients. We conducted a multicentric study to determine the prevalence and incidence of HCV infection in French haemodialysis units.

METHODS

Patients undergoing chronic haemodialysis in 56 French units (4718 patients) were systematically screened for anti-HCV antibodies using third-generation tests. The incidence was estimated by detecting HCV RNA in seronegative patients using a standardized real-time PCR assay on pooled samples.

RESULTS

Testing for HCV antibodies identified 361 patients with anti-HCV antibodies, giving a prevalence of 7.7%. Multivariate analysis demonstrated that anti-HCV status was linked to the time on haemodialysis, previous kidney transplantation and the presence of anti-HBc antibodies, whereas erythropoietin therapy and carrying out dialysis in dedicated spaces seem to protect against HCV infection. Only two of the 4357 patients without anti-HCV antibodies tested positive for HCV RNA, giving an estimated incidence of 0.05% new HCV infections/year. Molecular analyses indicated that the two patients probably acquired HCV outside the haemodialysis unit.

CONCLUSION

This decreased prevalence and incidence emphasizes the importance of adhering to the recommended universal infection-control precautions. Virological follow-up based on detecting anti-HCV antibodies with sensitive, specific new-generation serological tests could be adequate for dialysis units with few HCV infections. However, new infections in haemodialysis units should be identified by determining the HCV RNA status of seronegative patients. Standardized real-time PCR assays, plus pooling serum samples, make this a promising method for large-scale epidemiological studies.

Molecular epidemiology of a hepatitis C virus epidemic in a haemodialysis unit: outbreak investigation and infection outcome

Background

HCV is a leading cause of liver chronic diseases all over the world. In developed countries the highest prevalence of infection is reported among intravenous drug users and haemodialysis (HD) patients. The present report is to identify the pathway of HCV transmission during an outbreak of HCV infection in a privately run haemodialysis (HD) unit in Italy in 2005.

Methods

Dynamics of the outbreak and infection clinical outcomes were defined through an ambi-directional cohort study. Molecular epidemiology techniques were used to define the relationships between the viral variants infecting the patients and confirm the outbreak. Risk analysis and auditing procedures were carried out to define the transmission pathway(s).

Results

Of the 50 patients treated in the HD unit 5 were already anti-HCV positive and 13 became positive during the study period (AR = 28.9%). Phylogenic analysis identified that, all the molecularly characterized incident cases (10 out of 13), were infected with the same viral variant of one of the prevalent cases. The multivariate analysis and the auditing procedure disclosed a single event of multi-dose vials heparin contamination as the cause of transmission of the infection in 11 out of the 13 incident cases; 2 additional incident cases occurred possibly as a result of inappropriate risk management.

Discussion

More than 30% of all HCV infections in developed countries results from poor application of standard precautions during percutaneous procedures. Comprehensive strategy which included: educational programmes, periodical auditing on standard precaution, use of single-dose vials whenever possible, prospective surveillance for blood-borne infections (including a system of prompt notification) and risk assessment/management dedicated staff are the cornerstone to contain and prevent outbreaks in HD

Conclusions

The outbreak described should serve as a reminder to HD providers that patients undergoing dialysis are at risk for HCV infection and that HCV may be easily transmitted whenever standard precautions are not strictly applied.

An overview about hepatitis C: a devastating virus

Hepatitis C (HCV) is the disease that has affected around 200 million people globally. HCV is a life threatening human pathogen, not only because of its high prevalence and worldwide burden but also because of the potentially serious complications of persistent HCV infection. Chronicity of the disease leads to cirrhosis, hepatocellular carcinoma and end-stage liver disease. HCV positive hepatocytes vary between less than 5% and up to 100%, indicating the high rate of replication of viral RNA. HCV has a very high mutational rate that enables it to escape the immune system. Viral diversity has two levels; the genotypes and Quasiaspecies. Major HCV genotypes constitute genotype 1, 2, 3, 4, 5 and 6 while more than 50 subtypes are known. All HCV genotypes have their particular patterns of geographical distribution and a slight drift in viral population has been observed in some parts of the globe.

Analytical evaluation of HCV core antigen and interest for HCV screening in haemodialysis patients

BACKGROUND

It is important to diagnose a hepatitis C virus infection in the acute phase in order to reduce the incidence of this infection in high-risk populations like haemodialysis patients. But detection systems for serum HCV antibodies are insensitive in the acute phase because of the long serological window. Previous studies showed that the HCV core antigen (HCV Ag) may be an alternative to HCV RNA in this context.

OBJECTIVES

To evaluate the performances of the new Abbott ARCHITECT((R)) HCV Ag test and its usefulness in screening for HCV infections in haemodialysis patients.

STUDY DESIGN

The serum HCV Ag titre was compared to the HCV RNA viral load in 98 samples from HCV-infected patients to determine the correlation between the two markers and the influence of genotype. We screened 2752 patients from 37 French haemodialysis units who tested negative for HCV antibodies using the HCV Ag and RNA assays.

RESULTS

The HCV Ag titre was correlated with the HCV RNA (Spearman test coefficient 0.9041, p<0.0001) and all genotypes and subtypes were detected. The HCV Ag and HCV RNA results agreed well for haemodialysis patients. Diagnostic specificity of HCV Ag was high (99.2%) considering HCV RNA as the reference. The two seronegative patients (of 2752) who were HCV RNA positive were also HCV Ag positive.

CONCLUSIONS

The ARCHITECT HCV Ag test is a reliable, highly specific assay for screening acute HCV infections in haemodialysis units. It is a robust alternative to HCV RNA testing.

Infection control guidelines for prevention of health care-associated transmission of hepatitis B and C viruses

Viral hepatitis was first identified as an occupational hazard for health care workers more than 60 years ago. For the past few decades, hepatitis B has been one of the most significant occupational infectious risks for health care providers. With the increasing prevalence of hepatitis C infections around the world, occupational transmission of this flavivirus from infected patients to their providers has also become a significant concern. Several factors influence the risk for occupational blood-borne hepatitis infection among health care providers, among them: the prevalence of infection among the population served, the infection status of the patients to whom workers are exposed (ie, the source patient's circulating viral burden), the types and frequencies of parenteral and mucosal exposures to blood and blood-containing body fluids, and whether the patient or provider has been immunized with the hepatitis B vaccine. This article reviews patient-to-provider, patient-to-patient, and provider-to-patient transmission of hepatitis B and C in the health care setting. Current prevention strategies, precautions, and guidelines are discussed.

A shield against a monster: Hepatitis C in hemodialysis patients

Hepatitis C virus (HCV) infection is highly prevalent among patients on hemodialysis (HD). The prevalence of HCV infection in HD patients varies markedly from country to country. Some factors are especially related to these high prevalence rates, such as blood transfusions and length of dialysis time. Nosocomial routes of transmission including the use of contaminated equipment and patient-to-patient exposure is considered more important. Several prophylactic measures have been suggested to avoid infection by HCV in the HD environment.

Epidemiological characteristics and medical follow-up of 61 patients with acute hepatitis C identified through the hepatitis C surveillance system in France

This study aimed to describe current epidemiological and clinical characteristics, medical follow-up and outcome in the real practice of acute hepatitis C (AHC) patients. AHC cases were retrospectively identified through the French Hepatology Reference Centres Surveillance system and additional data were collected. Sixty-one patients with AHC were identified (sex ratio: M/F 1.7/1; mean age 39 years). Forty-four (72%) had documented seroconversion within a 6-month period. Main reported risk exposures were intravenous or nasal drug use (35%), invasive medical procedures (25%) and sexual contact with a HCV-positive partner (20%). Spontaneous clearance of HCV RNA was observed in seven out of 16 patients followed without therapy. This study confirms the major role of drug use in HCV transmission and highlights the role of invasive medical procedures and occupational exposure.

Occult hepatitis C virus infection is more common than hepatitis B infection in maintenance hemodialysis patients

Patients of end stage renal disease on maintenance hemodialysis were enrolled to study the prevalence of occult and dual hepatitis B virus (HBV) and hepatitis C virus (HCV) infection and non-occult hepatitis B and C virus infection. One hundred and two patients were enrolled. Thirty patients had HCV infection, three of them were positive in anti-HCV. So, 27 (90%) of HCV-positive patients had occult HCV infection. Eleven (11%) patients had HBV infection. Five patients were positive in anti-HBc or HBV-DNA, but negative in HBsAg (occult HBV infection). Three (3%) patients had dual HBV and HCV infection. None of the patients showed changes in viral markers during the follow-up of 8 mo on average (1-12 mo).

Transfusion-transmitted infections among multitransfused patients in Iran: a review

Transfusion-transmitted infections (TTI) continue to be a major challenge for Blood transfusion organizations across the world. The problem is more serious in the developing countries with lower economic means. Multitransfused patients (MTPs) in these countries are at higher risk of infection, and studies of infection in these patients can be a useful index for examining the blood safety filters in place. The present article reviews the situation in Iran, where prevalence of the major viruses of concern, namely, hepatitis B virus, hepatitis C virus (HCV) and human immunodeficiency virus, studied in these patients is reported over a 9-year period. It is demonstrated that HCV is the most prevalent TTI and remains a major health problem for these patients.

Hepatitis C in hemodialysis patients: current global magnitude, natural history, diagnostic difficulties, and preventive measures

Hepatitis C virus (HCV) infection is a significant cause of morbidity and mortality in hemodialysis (HD) patients. The reported prevalence of HCV among the HD population has varied greatly from 1.9 to 84.6% in different countries in recent years. The length of time on HD is generally believed to be associated with HCV acquisition in HD subjects. Nevertheless, several recent reports failed to recognize any significant role of blood transfusion. Although there are some considerations about the accuracy of serologic testing in detecting HCV in HD patients, the accumulated data in this review suggest the false-negativity rate to be not more than 1.66% (153/9,220). Therefore, substituting virologic for serologic testing in the routine diagnosis of HCV infection in HD patients seems unreasonable. Several phylogenetic analyzes of viral isolates suggested nosocomial patient-to-patient transmission of HCV among HD patients for which the main potential source is believed to be contaminated hands and articles. However, isolation of HCV-infected HD patients and use of dedicated machines are currently unjustified while strict adherence to universal precautions seems to be enough to control disease spread in HD units. The present article is an update on epidemiological and clinical features of HCV in HD population.

[Prevalence of anti-HCV antibodies and seroconversion incidence in five haemodialysis units in Morocco]

Dialysis patients are among groups at risk for development of hepatitis C infection (HCV). The aim of the study was to evaluate the prevalence and the incidence of seroconversion for HCV in five haemodialysis units in Morocco. The study was conducted during the period from September 2003 to September 2004. We studied 303 patients (148 females), mean age 49+/-16 years; dialysis duration was higher than five years in 64% of the cases. The prevalence of HCV infection was evaluated by using a fourth generation enzyme immunoassays. In the seronegative patients, we performed anti-HCV tests at three and six months intervals and monthly testing of alanine aminotransferase (ALT) activity and assessment of anti-HCV tests if the ALT activity was elevated. Moreover, risk factors, such as blood transfusion, surgery and other invasive procedures were recorded. Seroprevalence of HCV was 68.3%. Among 85 patients who were tested negative for anti-HCV at the entry of the study, four (4.60%) seroconverted in six month (estimated incidence: 9.41 new cases per year). HCV seropositivity was associated with longer duration of dialysis (p=0.000), and previous blood transfusions (p=0.047). The follow-up of the ALT in the seronegative patients did not show any significant variation. In conclusion, the prevalence and incidence of HCV infection in haemodialysis units in Morocco are dramatically elevated. High incidence seropositivity suggested nosocomial transmission of HCV; the dialysis processes itself, and blood transfusions are important risk factors for HCV transmission in these patients.

Analyzing pathogen transmission in the dialysis unit: time for a (schedule) change?

BACKGROUND AND OBJECTIVES

Infectious diseases and antimicrobial-resistant microorganisms are a growing problem for the dialysis population. The frequency of patient visits and intimate, prolonged physical contact with the inanimate environment during dialysis treatments make these facilities potentially efficient venues for nosocomial pathogen transmission. Isolation measures and infection control practices can be inconvenient and consume limited resources. Quantitative tools for analyzing the effects of different containment strategies can help to identify optimal strategies for further study. However, spatial and temporal considerations germane to the dialysis unit greatly complicate analyses relying on conventional mathematical approaches.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A stochastic, individual-based, Monte Carlo simulation tool that predicts the effects of various infection control strategies on pathogen dissemination through the dialysis unit in the face of diagnostic uncertainty was developed. The model was configured to emulate a medium-sized dialysis unit. The predicted consequences of various policies for scheduling patients who were suspected of being infectious were then explored, using literature-based estimates of pathogen transmissibility, prevalence, and diagnostic uncertainty.

RESULTS

Environmental decontamination was predicted to be of paramount importance in limiting pathogen dissemination. Temporal segregation (scheduling patients who were suspected of being infectious to dialysis shifts that are later in the day) was predicted to have the greatest effectiveness in reducing transmission, given adequate environmental decontamination between successive days.

CONCLUSIONS

Decontamination of the patient's environment (chair) can markedly attenuate pathogen dissemination. Temporal segregation could be a simple, low-cost, system-level intervention with significant potential to reduce nosocomial transmission in the dialysis unit.

Prevalence of occult hepatitis B and hepatitis C virus infections in Turkish hemodialysis patients

BACKGROUND AND OBJECTIVE

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are important causes of morbidity and mortality in maintenance hemodialysis patients. Although their exact prevalence is not known, HBV and HCV viral infections and occult viral hepatitis are frequent in these patients. This study aimed to determine the prevalence of occult HBV and HCV infections in maintenance hemodialysis patients.

MATERIALS AND METHODS

One hundred and eighty-eight end-stage renal disease patients on maintenance hemodialysis (100 male, mean age 49+/-29 [16-80] years, and mean duration of hemodialysis 98+/-66 [12-228] months) were enrolled in this study. Serological markers for HBV and HCV were determined with immunoenzymatic assay (ELISA) by using commercial diagnostic kits (Access and BioRad, Beckman-Coulter). HCV-RNA (Cobas Amplicor HCV kit) and HBV-DNA (Artus GmbH HBV kit) were determined quantitatively by polymerase chain reaction.

RESULTS

Among the patients screened, 25 (13.3%) had HBV infection alone and 38 (20.2%) had HCV infection alone, while seven (3.7%) had dual infection of both viruses. Serological markers for occult hepatitis B and occult hepatitis C were positive in five (2.7%) and nine (4.8%) of the patients, respectively. Isolated anti-HBc was positive in 12 (6.4%) of all patients, three (7.9%) of the patients with anti-HCV and two (40%) of the patients with occult hepatitis B. Isolated anti-HBc positivity was more frequent in patients with occult hepatitis B than in those without (40% [2/5] vs. 5.5% [10/183], p=0.002). None of the patients with HCV had occult hepatitis B.

CONCLUSIONS

Both occult and non-occult forms of HCV infection are more prevalent than HBV infection in hemodialysis patients. Especially the patients with isolated anti-HBc positivity should be tested for probable occult hepatitis B infection.

Acute hepatitis C virus infection assessment among chronic hemodialysis patients in the Southwest Parana State, Brazil

Background

Chronic hemodialysis patients are at higher risk for acquiring hepatitis C virus (HCV). The prevalence varies among different countries and hemodialysis centers. Although guidelines for a comprehensive infection control program exist, the nosocomial transmission still accounts for the new cases of infection. The aim of this study was analyze the follow up of newly acquired acute hepatitis C cases, during the period from January 2002 to May 2005, in the Hemodialysis Center, located in the Southwest region of Parana State, Brazil and to analyze the effectiveness of the measures to restrain the appearance of new cases of acute hepatitis C.

Methods

Patients were analyzed monthly with anti-HCV tests and ALT measurements. Patients with ALT elevations were monitored for possible acute hepatitis C.

Results

During this period, 32 new cases were identified with acute hepatitis C virus infection. Blood screening showed variable ALT levels preceding the anti-HCV seroconversion. HCV RNA viremia by PCR analysis was intermittently and even negative in some cases. Ten out of 32 patients received 1 mcg/kg dose of pegylated interferon alfa-2b treatment for 24 weeks. All dialysis personnel were re-trained to strictly follow the regulations and recommendations regarding infection control, proper methods to clean and disinfect equipment were reviewed and HCV-positive patients were isolated.

Conclusion

Laboratory tests results showed variable ALT preceding anti-HCV seroconversion and intermittent viremia. The applied recommendations contributed importantly to restrain the appearance of new cases of acute hepatitis C in this center and the last case was diagnosed in May 2004.

Infection by the hepatitis C virus in chronic renal failure patients undergoing hemodialysis in Mato Grosso state, central Brazil: a cohort study

BACKGROUND

Hepatitis C virus (HCV) is a significant problem for patients undergoing hemodialysis therapy. This situation has never been studied in Mato Grosso state, central Brazil. This study was conducted aiming to estimate the prevalence of the anti-HCV and the incidence of seroconversion in the main metropolitan region of the state.

METHODS

433 patients from the six hemodialysis units were interviewed and anti-HCV was tested by a third-generation enzyme immunoassay. An open cohort of patients who tested negative for anti-HCV at the entry of the study was created and seroconversions was assessed monthly. The staff responsible for the units were interviewed to assess whether the infection control measures were being followed. Logistic and Cox regression analysis were performed in order to assess risk factor to HCV.

RESULTS

The entry on the study took place between January 2002 and June 2005. 73 out of 433 (16.9%, CI 95%: 13.3-20.8) was found to be anti-HCV reactive. The multivariate analysis indicated as risk factors associated to anti-HCV the duration of the hemodialysis treatment, the number of transfusions received, and the unit of treatment. An open cohort of 360 patients who tested negative for anti-HCV was created, with a following average of 24 (+/- 15) months. Forty seroconversions were recorded corresponding to an incidence density of 4.6/1000 patient-months, ranges 0 to 30 among the units. Cox regression indicated the time of hemodialysis (RR = 2.2; CI 95%: 1.1-4.6; p < 0.05) and the unit where treatment was performed (RR = 42.4; CI 95%: 9.9-180.5; p < 0.05) as risk factors for seroconversion. The three units with highest anti-HCV prevalence and incidence were identified as those that more frequently failed to apply control measures.

CONCLUSION

The study demonstrated high prevalence and incidence of anti-HCV in some of the hemodialysis units. Time on hemodialysis therapy was an independent factor associated to HCV. Blood transfusion was associated with anti-HCV in initial survey but was not important in incident cases. Failure of applying control measures was more evident in units with the highest HCV prevalence and incidence. The results suggest that nosocomial transmission was the main spread factor of HCV in the studied population.

[Principles of an outbreak investigation in public health practice]

An outbreak (or epidemic) is a higher number of cases of a given disease in a given population and time interval. A timely investigation has for aim to identify the source and vehicle of the outbreak and provides unique opportunities to better understand its occurrence and the role of contributing risk factors to implement the most appropriate measures to control it and prevent further recurrences. The investigation of an outbreak is based on a multidisciplinary approach (clinical, epidemiological, environmental, and microbiological) with a descriptive and analytical (hypothesis testing) phase. In this article, we describe the methodological approach of a field outbreak investigation illustrated by examples taken from our experience. The investigation includes the following steps: establishing the existence of the outbreak; defining the disease; finding cases; describing cases by time, place, and person characteristics; establishing a hypothesis related to the mode of occurrence; testing the hypotheses; conducting an environmental investigation; conducting a microbiological investigation; controlling the outbreak, preventing further occurrences, and writing an investigation report to share experience with the public health and scientific community. The investigation of an outbreak is an evolving process: information gathered or conclusions made at a given stage must be fully used for following steps. The social, institutional, and political background associated with outbreaks usually makes their investigation complex and should be taken into account. The earlier the outbreak is detected and investigated in close relation with public health authorities, the greater will be the potential preventive impact of control measures.

Retrospective investigation of patients exposed to possible transmission of hepatitis C virus by a capillary blood glucose meter

A 75-year-old female with no known risk factors for hepatitis C virus (HCV) infection was hospitalized and a diagnosis of HCV seroconversion was established (HCV immunoblot and a positive quantitative viral load). An epidemiological investigation revealed that, during a previous hospitalization resulting in a diagnosis of diabetes, she had shared a Glucotrend capillary blood glucose meter (CBGM; Roche Diagnostics, France) with a known HCV-positive diabetic patient. Poor hygiene practices were observed when using this device. Since the Glucotrend CBGM had been purchased, the suspected source patient had been hospitalized eight times and another 19 diabetic patients with known anti-HCV antibodies also regularly attended the same hospital. Consequently, 35 diabetic patients who had been hospitalized at the same time as the suspected source patient and 1305 patients who had used the Glucotrend CBGM were invited to undergo serum anti-hepatitis B virus, anti-HCV and anti-human immunodeficiency virus testing. Among the 35 diabetic patients, none of the 24 subjects tested were positive. Among the 1305 other patients, 995 were tested and 19 (2%) were anti-HCV positive. Although this prevalence is higher than that reported in the general French population, this excess risk cannot be attributed to use of the CBGM. Furthermore, molecular analysis showed that the two HCV strains isolated did not belong to the same phylogenetic cluster. However, as a result of this incident, measures were taken to minimize the transmission of bloodborne viruses in the hospital concerned. Other French hospitals were informed by a national alert message from the French Agency for the Safety of Health Products.

Incidence of HCV infection in French hemodialysis units: a prospective study

A large prospective study was carried out from 1997 to 2000 in 25 French hemodialysis units including 1,323 patients to determine the incidence of hepatitis C virus (HCV) infection. Monthly testing of alanine aminotransferase (ALT) activity, and assessment of HCV RNA and anti-HCV antibodies if the ALT activity was elevated, identified 14 new infections in 7 different units, giving an incidence of 0.4% new HCV infections per year. Molecular analyses and epidemiological data indicated that five patients became infected with HCV outside the unit where they were dialyzed, while the nine remaining patients acquired HCV from infected patients on dialysis during the same shift at the same unit. HCV was cleared in six of the seven (85.7%) patients with acute hepatitis C who were given standard doses of alpha-interferon (alpha-IFN). The persistence of nosocomial transmission of HCV in hemodialysis units emphasizes the need to implement infection control practices. Identifying new infections is crucial because alpha-IFN treatment results in long term clearance of HCV RNA in a large proportion of patients.