Transmission visualizations of healthcare infection clusters: A scoping review

OBJECTIVE

To evaluate infectious pathogen transmission data visualizations in outbreak publications.

DESIGN

Scoping review.

METHODS

Medline was searched for outbreak investigations of infectious diseases within healthcare facilities that included ≥1 data visualization of transmission using data observable by an infection preventionist showing temporal and/or spatial relationships. Abstracted data included the nature of the cluster(s) (pathogen, scope of transmission, and individuals involved) and data visualization characteristics including visualization type, transmission elements, and software.

RESULTS

From 1,957 articles retrieved, we analyzed 30 articles including 37 data visualizations. The median cluster size was 20.5 individuals (range, 7-1,963) and lasted a median of 214 days (range, 12-5,204). Among the data visualization types, 10 (27%) were floor-plan transmission maps, 6 (16%) were timelines, 11 (30%) were transmission networks, 3 (8%) were Gantt charts, 4 (11%) were cluster map, and 4 (11%) were other types. In addition, 26 data visualizations (70%) contained spatial elements, 26 (70%) included person type, and 19 (51%) contained time elements. None of the data visualizations contained contagious periods and only 2 (5%) contained symptom-onset date.

CONCLUSIONS

The data visualizations of healthcare-associated infectious disease outbreaks in the systematic review were diverse in type and visualization elements, though no data visualization contained all elements important to deriving hypotheses about transmission pathways. These findings aid in understanding the visualizing transmission pathways by describing essential elements of the data visualization and will inform the creation of a standardized mapping tool to aid in earlier initiation of interventions to prevent transmission.

Convex hulls in hamming space enable efficient search for similarity and clustering of genomic sequences

Background

In molecular epidemiology, comparison of intra-host viral variants among infected persons is frequently used for tracing transmissions in human population and detecting viral infection outbreaks. Application of Ultra-Deep Sequencing (UDS) immensely increases the sensitivity of transmission detection but brings considerable computational challenges when comparing all pairs of sequences. We developed a new population comparison method based on convex hulls in hamming space. We applied this method to a large set of UDS samples obtained from unrelated cases infected with hepatitis C virus (HCV) and compared its performance with three previously published methods.

Results

The convex hull in hamming space is a data structure that provides information on: (1) average hamming distance within the set, (2) average hamming distance between two sets; (3) closeness centrality of each sequence; and (4) lower and upper bound of all the pairwise distances among the members of two sets. This filtering strategy rapidly and correctly removes 96.2% of all pairwise HCV sample comparisons, outperforming all previous methods. The convex hull distance (CHD) algorithm showed variable performance depending on sequence heterogeneity of the studied populations in real and simulated datasets, suggesting the possibility of using clustering methods to improve the performance. To address this issue, we developed a new clustering algorithm, k-hulls, that reduces heterogeneity of the convex hull. This efficient algorithm is an extension of the k-means algorithm and can be used with any type of categorical data. It is 6.8-times more accurate than k-mode, a previously developed clustering algorithm for categorical data.

Conclusions

CHD is a fast and efficient filtering strategy for massively reducing the computational burden of pairwise comparison among large samples of sequences, and thus, aiding the calculation of transmission links among infected individuals using threshold-based methods. In addition, the convex hull efficiently obtains important summary metrics for intra-host viral populations.

Risk factors associated with nosocomial infections among end stage renal disease patients undergoing hemodialysis: A systematic review

Background

Profound healthcare challenges confront societies with an increase in prevalence of end-stage renal disease (ESRD), which is one of the leading causes of morbidity and mortality worldwide. Due to several facility and patient related factors, ESRD is significantly associated with increased morbidity and mortality attributed to infections.

Aims and objective

The aim of this study was to assess systematically the characteristics of patients and risk factors associated with nosocomial infections among ESRD patients undergoing hemodialysis.

Methods

A systematic literature search was performed to identify eligible studies published during the period from inception to December 2018 pertaining to risk factors associated with nosocomial infections among hemodialysis patients. The relevant studies were generated through a computerized search on five databases (PubMed, EBSCOhost, Google Scholar, ScienceDirect and Scopus) using the Mesh Words: nosocomial infections, hospital acquired infections, healthcare associated infections, end stage renal disease, end stage renal failure, hemodialysis, and risk factors. The complete protocol has been registered under PROSPERO (CRD42019124099).

Results

Initially, 1411 articles were retrieved. Out of these, 24 were duplicates and hence were removed. Out of 1387 remaining articles, 1337 were removed based on irrelevant titles and/or abstracts. Subsequently, the full texts of 50 articles were reviewed and 41 studies were excluded at this stage due to lack of relevant information. Finally, nine articles were selected for this review. Longer hospital stay, longer duration on hemodialysis, multiple catheter sites, longer catheterization, age group, lower white blood cell count, history of blood transfusion, and diabetes were identified as the major risk factors for nosocomial infections among hemodialysis patients.

Conclusion

The results of this review indicate an information gap and potential benefits of additional preventive measures to further reduce the risk of infections in hemodialysis population. Moreover, several patient-related and facility-related risk factors were consistently observed in the studies included in this review, which require optimal control measures.

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.

Transmission of hepatitis C virus infection in hemodialysis: Current concepts

A variety of epidemiological data provides evidence for the occurrence of nosocomial transmission of hepatitis C virus (HCV) infection to hemodialysis (HD) patients. The most important factor implicated in HCV transmission between patients treated in the same dialysis unit is cross-contamination from supplies and surfaces as a result of failure of staff to follow infection control procedures. Parts of the HCV genome are highly variable and lend themselves to fingerprinting of each isolate using nucleic acid testing (NAT) and sequencing. This approach has permitted investigation of possible transmission routes within HD units. A systematic review of molecular virology papers revealed transmission of HCV via internal fluid pathways of the dialysis machines in a minority of reports only. Dialyzer reuse was not identified as a risk factor for HCV acquisition in multicenter databases. No randomized controlled trials exist on the impact of isolation on the risk of transmission of HCV to hemodialysis patients. A Belgian prospective multicenter study showed a reduction from 1.4% to 0% in the annual incidence of seroconversion for HCV without any isolation measures, by implementation of strict infection control procedures designed to prevent transmission of blood-borne pathogens, including HCV. However, an isolation policy for HCV-infected dialysis patients should be considered in dialysis units where nosocomial transmission of HCV persists despite reinforcement and audit of hygienic precautions for hemodialysis. Routine audit precautions (general and for dialysis machines) are recommended on a regular basis within HD units.

Molecular characterization of hepatitis C virus in end-stage renal disease patients under hemodialysis

New direct-acting antiviral (DAA) agents are in development or already approved for the treatment of chronic hepatitis C virus (HCV) infection. The effectiveness of these drugs is related to the previous existence of resistant variants. Certain clinical conditions can allow changes in immunological characteristics of the host and even modify genetic features of viral populations. The aim of this study was to perform HCV molecular characterization from samples of end-stage renal disease patients on hemodialysis (ESRD-HD). Nested PCR and Sanger sequencing were used to obtain genetic information from the NS5B partial region of a cohort composed by 86 treatment-naïve patients. Genomic sequences from the Los Alamos databank were employed for comparative analysis. Bioinformatics methodologies such as phylogenetic reconstructions, informational entropy, and mutation analysis were used to analyze datasets separated by geographical location, HCV genotype, and renal function status. ESRD-HD patients presented HCV genotypes 1a (n = 18), 1b (n = 16), 2a (n = 2), 2b (n = 2), and 3a (n = 4). Control subjects were infected with genotypes 1a (n = 11), 1b (n = 21), 2b (n = 4), and 3a (n = 8). Dataset phylogenetic reconstruction separated HCV subtype 1a into two distinct clades. The entropy analysis from the ESRD-HD group revealed two amino acid positions related to an epitope for cytotoxic T lymphocytes and T helper cells. Genotype 1a was found to be more diverse than subtype 1b. Also, genotype 1a ERSD-HD patients had a higher mean of amino acids changes in comparison to control group patients. The identification of specific mutations on epitopes and high genetic diversity within the NS5B HCV partial protein in hemodialysis patients can relate to host immunological features and geographical distribution patterns. This genetic diversity can affect directly the new DAA's resistance mechanisms.

Efficient detection of viral transmissions with Next-Generation Sequencing data

BACKGROUND

Hepatitis C is a major public health problem in the United States and worldwide. Outbreaks of hepatitis C virus (HCV) infections associated with unsafe injection practices, drug diversion, and other exposures to blood are difficult to detect and investigate. Molecular analysis has been frequently used in the study of HCV outbreaks and transmission chains; helping identify a cluster of sequences as linked by transmission if their genetic distances are below a previously defined threshold. However, HCV exists as a population of numerous variants in each infected individual and it has been observed that minority variants in the source are often the ones responsible for transmission, a situation that precludes the use of a single sequence per individual because many such transmissions would be missed. The use of Next-Generation Sequencing immensely increases the sensitivity of transmission detection but brings a considerable computational challenge because all sequences need to be compared among all pairs of samples.

METHODS

We developed a three-step strategy that filters pairs of samples according to different criteria: (i) a k-mer bloom filter, (ii) a Levenhstein filter and (iii) a filter of identical sequences. We applied these three filters on a set of samples that cover the spectrum of genetic relationships among HCV cases, from being part of the same transmission cluster, to belonging to different subtypes.

RESULTS

Our three-step filtering strategy rapidly removes 85.1% of all the pairwise sample comparisons and 91.0% of all pairwise sequence comparisons, accurately establishing which pairs of HCV samples are below the relatedness threshold.

CONCLUSIONS

We present a fast and efficient three-step filtering strategy that removes most sequence comparisons and accurately establishes transmission links of any threshold-based method. This highly efficient workflow will allow a faster response and molecular detection capacity, improving the rate of detection of viral transmissions with molecular data.

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.

A Large Outbreak of Hepatitis C Virus Infections in a Hemodialysis Clinic

BACKGROUND In November and December 2012, 6 patients at a hemodialysis clinic were given a diagnosis of new hepatitis C virus (HCV) infection. OBJECTIVE To investigate the outbreak to identify risk factors for transmission. METHODS A case patient was defined as a patient who was HCV-antibody negative on clinic admission but subsequently was found to be HCV-antibody positive from January 1, 2008, through April 30, 2013. Patient charts were reviewed to identify and describe case patients. The hypervariable region 1 of HCV from infected patients was tested to assess viral genetic relatedness. Infection control practices were evaluated via observations. A forensic chemiluminescent agent was used to identify blood contamination on environmental surfaces after cleaning. RESULTS Eighteen case patients were identified at the clinic from January 1, 2008, through April 30, 2013, resulting in an estimated 16.7% attack rate. Analysis of HCV quasispecies identified 4 separate clusters of transmission involving 11 case patients. The case patients and previously infected patients in each cluster were treated in neighboring dialysis stations during the same shift, or at the same dialysis station on 2 consecutive shifts. Lapses in infection control were identified. Visible and invisible blood was identified on multiple surfaces at the clinic. CONCLUSIONS Epidemiologic and laboratory data confirmed transmission of HCV among numerous patients at the dialysis clinic over 6 years. Infection control breaches were likely responsible. This outbreak highlights the importance of rigorous adherence to recommended infection control practices in dialysis settings.

Accurate Genetic Detection of Hepatitis C Virus Transmissions in Outbreak Settings

Hepatitis C is a major public health problem in the United States and worldwide. Outbreaks of hepatitis C virus (HCV) infections are associated with unsafe injection practices, drug diversion, and other exposures to blood and are difficult to detect and investigate. Here, we developed and validated a simple approach for molecular detection of HCV transmissions in outbreak settings. We obtained sequences from the HCV hypervariable region 1 (HVR1), using end-point limiting-dilution (EPLD) technique, from 127 cases involved in 32 epidemiologically defined HCV outbreaks and 193 individuals with unrelated HCV strains. We compared several types of genetic distances and calculated a threshold, using minimal Hamming distances, that identifies transmission clusters in all tested outbreaks with 100% accuracy. The approach was also validated on sequences obtained using next-generation sequencing from HCV strains recovered from 239 individuals, and findings showed the same accuracy as that for EPLD. On average, the nucleotide diversity of the intrahost population was 6.2 times greater in the source case than in any incident case, allowing the correct detection of transmission direction in 8 outbreaks for which source cases were known. A simple and accurate distance-based approach developed here for detecting HCV transmissions streamlines molecular investigation of outbreaks, thus improving the public health capacity for rapid and effective control of hepatitis C.

Transmission of hepatitis C virus in dialysis units: a systematic review of reports on outbreaks

BACKGROUND

Hepatitis C virus (HCV) outbreaks among patients on hemodialysis are still an important health concern all over the world.

AIMS

We performed a systematic review of reports on HCV outbreaks within dialysis units of developed and less-developed countries (between 1992 and 2015) to evaluate risk factors and practices associated with patient-to-patient transmission of HCV in this setting.

METHODS

The research was performed using the PubMed Database and the Outbreak Database; studies were selected according to the PRISMA algorithm. Inclusion criteria were established before the papers were retrieved in order to avoid selection biases.

RESULTS

36 papers reported on 45 outbreaks that involved 335 unique patients on maintenance hemodialysis; no fatal cases were detected. Nosocomial transmission of HCV was confirmed by phylogenetic analysis in most (n=31; 69%) reports. Sharing contaminated hemodialysis machines and multidose vials (heparin or saline solution) was suggested responsible for HCV transmission in 8 (18%) and 6 (13%) outbreaks, respectively. Breaches in environmental cleaning and disinfection practices, and failures in medication preparation and administration practices was considered in 29 (65%) outbreaks; however, the exact mechanism of transmission of HCV could not be ascertained in each facility where an outbreak occurred.

CONCLUSIONS

Our systematic review of reports on hepatitis C virus outbreaks shows that, although the full extent of HCV transmission in dialysis units is unknown, outbreaks continue to occur. Full compliance to standard/specific infection control procedures and routine serologic screening for HCV antibody play a pivotal role for preventing the transmission of HCV within hemodialysis units.

Epidemiology of hepatitis C in Europe

The advent of potent and safe direct-acting antivirals against the hepatitis C virus has the potential of fulfilling the dream of eliminating this infection and its impact on global public health. However, even if effective drugs are at hand, most patients remain unaware of their infection, which may be recognized only in late stages when dire complications have occurred. Europe is not spared by this scourge, with its estimated 19,000,000 persons infected, and knowledge of the epidemiology of HCV and its drivers is a critical tool in fighting this virus. A thorough review is provided on the extent of the HCV epidemic across Europe, with a discussion of the most important subgroups affected, and of the risk factors of infection, both traditional and new.

Minimizing the risk of non-vertical, non-sexual HIV infection in children--beyond mother to child transmission

After witnessing an episode of poor injection safety in large numbers of children in a rural under-resourced hospital in Uganda, we briefly review our own experience and that of others in investigating HIV infection in children considered unlikely to be through commonly identified routes such as vertical transmission, sexual abuse or blood transfusion. In the majority of cases, parents are HIV uninfected. The cumulative experience suggests that the problem is real, but with relatively low frequency. Vertical transmission is the major route for HIV to children. However, factors such as poor injection safety, undocumented surrogate breast feeding, an HIV-infected adult feeding premasticated food to a weaning toddler, poor hygienic practice in the home and using unsterilised equipment for minor surgical or traditional procedures are of cumulative concern.

Hepatitis C viremia and genotype distribution among a sample of nonmedical prescription drug users exposed to HCV in rural Appalachia

Research has demonstrated that hepatitis C (HCV) genotype distribution varies geographically and demographically. This exploratory study examines HCV viremia, viral concentration, and genotype distribution among anti-HCV positive, rural Appalachian nonmedical prescription drug users. The study population was randomly selected from a pool of 200 anti-HCV positive participants in a longitudinal study. Those randomly chosen were representative of the overall pool in terms of demographics, drug use, and other risk behaviors. Participants were tested serologically for HCV RNA, viral concentration, and genotype, and interview-administered questionnaires examined behavioral and demographic characteristics. Of the 81 participants, 69% tested RNA positive, 59% of which had viral loads exceeding 800,000 IU/ml. Approximately 66% of the RNA positive sample had genotype 1a; types 2b (16%) and 3a (13%) were less common. RNA positive participants were not significantly different than RNA negative participants demographically or behaviorally. Likewise, with the exception of education, genotype 1 participants were not significantly different than those with genotype 2 or 3. The prevalence of active HCV infection highlights a need for prevention and treatment in this population. However, the predominance of genotype 1 may present challenges due to its association with decreased responsiveness to drug treatment, although the novel class of direct-acting antivirals such as telaprevir and boceprevir offer new hope in this regard. The prevalence of genotype 1 may also foreshadow heightened burden of hepatocellular carcinoma and elevated healthcare expenditures. More research is needed to characterize HCV infection and genotype in this population.

Re-infection following sustained virological response with a different hepatitis C virus genotype: implications for infection control policy

We report the case of a 45-year-old haemodialysis patient who achieved a sustained virological response (SVR) following pegylated interferon therapy for hepatitis C virus (HCV) genotype 2 infection. He was subsequently cohorted with other HCV-infected dialysis patients and became re-infected with HCV genotype 3a. Epidemiological and molecular investigations identified a highly viraemic HCV genotype 3a-infected dialysis patient as the likely source of this infection. This critical incident informed a revision to local and national infection control policy regarding the dialysis management of patients who achieve an SVR following anti-viral treatment.

Transmission of hepatitis C virus to recipients of parenteral vitamin therapy in a primary care facility

BACKGROUND AND OBJECTIVES

The Australian prevalence of hepatitis C virus (HCV) is approximately 1%, with the majority of cases acquired through injecting drug use. However, occasionally HCV infection occurs in healthcare settings. Three new HCV infections were identified amongst patients attending a general practice in Sydney, Australia, specialising in parenteral vitamin therapy.

STUDY DESIGN

An investigation was conducted to identify the source of infection and mechanism of transmission. Molecular analysis was conducted by sequencing the HCV NS5A, Core and NS5B regions.

RESULTS

Two sources were identified using molecular epidemiology - a genotype 3a case was the source for a case acquired in late 2004 and a genotype 1b case the source for one case acquired in late 2006 and another in early 2007. The common risk factor was parenteral vitamin C therapy.

CONCLUSIONS

Inadequate infection control was apparent and likely to have resulted in blood contamination of the healthcare workers, their equipment, the clinic environment and parenteral medications. Molecular and clinical epidemiology clearly identified parenteral transmission of HCV, highlighting the risks of blood contamination of parenteral equipment and use of multi-dose flasks on more than one patient.

Prevention of infection in patients with chronic kidney disease. Part II: healthcare-associated infections

This second article, in a three-part CE series on the prevention of infection in patients with chronic kidney disease, focuses on healthcare-associated infections and blood borne viruses that are prevalent within the haemodialysis environment. It also informs the reader of the relevant infection and prevention precaution guidelines and their application within a haemodialysis setting.

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 health care-associated transmission of hepatitis B and C viruses

The term "molecular epidemiology" has been ascribed to a host of different activities that involve gene-sequence analysis. Some examples of molecular epidemiology include modeling exercises of phylogenetic trees to reconstruct epidemics; studies of the evolution of hepatitis C virus (HCV); rates of nucleotide substitution in the hepatitis B virus (HBV) surface (S) gene; variations in the core promoter/pre-core/core region of HBV genotype C from different sources; analysis of HBV surface antigen mutations; molecular clock analyses of the short-term evolution of HCV; and analyses of clades and surface antigen polymorphisms of HBV. However, for most epidemiologists molecular epidemiology of viral hepatitis usually refers to studies of gene-sequence homology in HBV or HCV recovered from people in the community or an institution that allows better characterization and assignment of related clusters of infection.

Most common genotypes and risk factors for HCV in Gaza strip: a cross sectional study

BACKGROUND

The present work aims at determining HCV genotypes in patients with chronic HCV infection, in Gaza strip, Palestine. The most common risk factors for HCV transmission were also evaluated in conjunction with the genotyping data.

RESULTS

The study shows that there are only two major genotypes of HCV in Gaza Strip: Genotype 1 (subtypes 1a and 1b) collectively contribute to 28.3% of the cases, and genotype 4 (subtypes 4a and 4c/d) collectively contribute to 64.1% of the cases. Mixed infection with the two genotypes was also present among 7.6% of the cases. In this study a statistically significant relationship was established between the distribution of these genotypes and the patients' living place, traveling history, history of blood transfusion and history of surgical operations.

CONCLUSION

The present study is the first to link HCV genotyping in Gaza strip with its possible roots of transmission. Traveling to endemic countries, especially Egypt; blood transfusion and surgical operations are major roots of HCV infection in Gaza strip. The results indicate that iatrogenic and nosocomial procedures may be responsible for the majority of HCV infections in Gaza strip.