Iranian Journal of Public Health
Volume:37 Issue: 3, Autumn 2008

Collection of multiple processes that increase the chronological age of an organism leading to death is defined as aging, and even though important, it is poorly understood. Recent research has shown that aging is due to biochemical and genetic changes, in interaction with environmental effects, including diet and nutrition. Most knowledge on aging is based on ge netic model system, but its molecular mechanisms are still not very clear. Discoveries in molecular biology have made way to look for candidate genes influencing lifespan. Furthermore, new investigations have stressed on the roles of mitochondria as the major generators and direct targets of reactive oxygen species. This paper reviews some recent literature on genes and ag ing in model system, then discusses the role of mitochondria and nutrients in human aging.

Mutations of GJB2 gene encoding connexion 26 are the most common cause of hearing loss in many popula tions. A very wide spectrum of GJB2 gene mutations associated with hearing loss have been detected but pathogenic role has been tested only for a part of them. In this study, we have provided genetic evidence on the pathogenicity of our previ ously reported novel GJB2 allelic variants. The pathogenic role of GJB2 allelic variants were assessed using co segregation of each allelic variant with hear ing loss in family members, absence of the allelic variants in control populations, coexistence with a second GJB2 mutation, na ture of the amino acid substitution and evolutionary conservation of the appropriate amino acid. The GJB2 allelic variants including 363delC, 327delGGinsA, H16R and G200R have been co segregated with auto somal recessive non syndromic hearing loss in five families and are not found in control subjects. The G130V and K102Q were found in heterozygous state in two deaf individuals. G130V results in an exchange a residue highly conserved among all the connexins but was found with a rate of 1% in control subjects and K102Q results in an exchange a residue not con served among all the connexins and not identified in control subjects. We conclude that, 363delC, 327delGGinsA, H16R and G200R may be pathogenic. However, the pathogenic ity and inheritance of K102Q and G130V can not be assessed clearly and remains to be identified.

Molecular biomarkers are valuable in evaluation the course of malignancies. In this study, the relationship be tween HER2/neu, p53, steroid receptors and clinicopathological features of patients with breast cancer has been assessed. Three hundred thirty nine women with a primary diagnosis of breast cancer from 2001 to 2006 were included. They were evaluated for tumor features. The content of the steroid hormone receptors and expression of HER2/neu and p53 was also examined by immunohistochemistry assay. From patients arrived at this study, 52%, 36%, 46.5% and 44% were positive for HER2/neu, p53, ER and PR respec tively. No association was found between most of pairs. HER2/neu expression significantly related with grade (P= 0.016). P53 had considerable reverse relation with axillary lymph node involvement and primary distant metastasis (P= 0.010 and P= 0.023, respectively). A significant association was found between PR and lymph node involvement (P= 0.038). This study present the pattern of prognostic biomarkers in breast cancer for the first time in northeast of Iran and suggests to conduct larger studies regarding other effective variables include demographic ones.

To determine the health needs of people with multiple sclerosis living in the Southern Derbyshire region of the UK, using a quality of life postal questionnaire. This was a population-based survey using a postal questionnaire comprising the 54-item Multiple Sclerosis Qual ity of life questionnaire (MSQOL-54), Nottingham Extended Activities of Daily Living (ADL), and some additional demo graphic questions. A postal questionnaire was sent via 40 health practices (50% of general practitioners) in Southern Derby shire to all patients diagnosed with Multiple Sclerosis confirmed by a neurologist. Two hundred and one completed questionnaires (from 223 respondents) were returned using pre-paid postage. Respondents were divided into those with mild (41%), moderate (36%) and severe (23%) disability on the basis of their ADL scores. Seventy seven percent (155) of respondents were women. The POQL mean scores for three groups of mild, moderate and severe disability were 12.02.8, 9.53.0, and 8.03.5 (out of 17), respectively. The regression model showed a relationship between disability scores and POQL scores (Beta=0.58, P= 0.000). For the three groups of disabled people, different priorities emerged in relation to POQL, indicating that ser vices seeking to improve quality of life in these groups must identify and target the relevant issues appropriately and be sensi tive to the differing requirements reported by individuals at different levels of disability. Studies of this type are becom ing increasingly important for determining which outcomes should be measured when evaluating interventions de signed to maintain well-being and protect the health of patients with MS

Rh (Rhesus) is a highly complex blood group system in man deeply rooted in transfusion medicine. Isolation of RhD from cord blod, cloning and expression of recombinant RhD antigen in bacterial expression system was the aim of this study. Total RNAs were extracted from cord blood (O+). The quality of RNA was determined by electrophoresis. In or der to obtain coding sequence of RhD antigen cDNA was synthesized and Rh D gene was amplified by RT-PCR. The iso lated RhD gene was cloned to pUC18 vector and transformed to DH5α. The confirmed construct was sub cloned into expres sion vector, pBADgIII/A, and expressed in Top10 E.coli. The expressed protein was characterized by SDS-PAGE and western blot analysis. Antigenicity of the expressed protein was assessed by ELISA using commercially available hu man anti-RhD polyclonal antibody with peroxidase conjugated goat anti-human IgG, IgM, IgA as secondary antibody. RhD gene was successfully cloned and expressed. The expected size of recombinant RhD protein was detected in SDS-PAGE, and confirmed by dot and western blot analysis. RhD antibody reacted with recombinant RhD antigen as well as with RhD polypeptide extracted from RBCs membrane. The recombinant RhD may be helpful to further investigate the molecular basis of RhD protein and could be applica ble for production anti- D antibody in an animal model

To clinically characterize the cutaneous leishmaniasis and identify the causative parasite species in Mirjaveh, an important geographical region across the border of Iran-Pakistan at Southeast of Iran. A number of 116 patients during a year since March 2005 to April 2006, subjected to the study. Clinical infor mation collected and scrapings were taken from cutaneous lesions and used for microscopic examination, NNN cultivation and kinetoplast DNA-PCR amplification. The cases comprised of 48 males and 68 females, 84 (72.4%) Iranians and 32 (27.6%) non-Iranians. They aged between 2 months to 68 years with the most affection of children, 0-10 years (55.2%). The patients presented a total of 248 active lesions with an average of 2.14. The ulcers distributed mostly on upper extremity (42.3%) then on face (32.7%), fol lowed by lower extremity (20.6%) and other parts (4.4%). The majority of ulcers stated to be developed rapidly, <1 month (40.3%) or 1-2 months (45.2%). However, from 248 ulcers, only 19 (7.7%) found to be wet and the remaining were dry or moderately wet, 45 (18.1%) and 184 (74.2%), respectively. kDNA-PCR assay detected 51 out of 73 samples, all of which were identified as L. major, the causative agent of zoonotic cutaneous leishmaniasis. L. major is the species responsible for cutaneous leishmaniasis in Mirjaveh, however the pattern of clinical findings, does not completely resemble the ZCL characteristics. These indicate that the manifestation of the lesions may not necessarily correspond to the Leishmania species and may be unreliable to conclude the speciation of parasite without labo ratory identification.

Aspergillus species are associated with allergic bronchopulmonary disease, mycotic keratitis, otomycosis, na sal sinusitis and invasive infection. In this study, we developed a PCR-Single Strand Confomational Polymorphism method to identify the most common Aspergillus species and we showed some advantages of this method comparing a PCR-Restric tion Fragment Length Polymorphism with our designed restriction enzyme. We selected ITS2, as a short fragment within the rDNA region (length size: 330 bp) to be amplified as small size PCR product. We mixed 5 ml of the PCR product with an equal volume of loading buffer and followed by incubation for 5 min at 95º C and quenching in an ice bath. The mixture was applied to a 6%-12% Gradient Poly acryl amide gel to run in a verti cal electrophoresis, then gel was stained with ethidium bromide and silver nitrate which followed by an ethidium bro mide staining. Our results of restriction digestion showed a fine identification of 7 tested Aspergillus species dur ing 5-6 hours af ter an overnight mycelial growth. As our results some of tested Aspergillus species: A. nidulans, A. fisheri, A. quad ricincta, (A. fumigatus and A. niger) as a group and (A. flavus, A. tereus and A. ochraceus) as another group, can be dis criminated. More over SSCP analysis enabled us to identify above Aspergillus species within 8-12 h after an over night growth without us ing an expensive restriction enzyme. It is concluded that Single Strand Conformational Polymorphism is a simple and rapid method for identifica tion of some medically important Aspergillus

We reviewed the monthly laboratory surveillance reports and hospital laboratory database in Dhahira region, Oman. All patients for whom a stool sample examination request was made from 1st January 2002 to 31st December 2006 (5 years) were included in the study. Antimicrobial resistance pattern was studied for 2 years period. The cultures were done using standard laboratory procedures and antibiotic sensitivity by Kirby Bauer disc diffusion method. Of the 85,210 stool samples examined, 18% showed positive result for one or more parasitic infection. The most common were E. hystolytica (7.1%), Giardia (7.9%) and E. coli (1.9%). A total of 7,830 cultures were done, among them 11.4% showed positive result for bacterial pathogen. The most common were Salmonella (5.8%) and Shigella species (4.4%). The antimicrobial susceptibility patterns of 265 bacterial pathogens were analyzed. Of the Shigella strains, 71.8% were resistant to trimethoprim/sulphamethoxazole (SXT) and 39.4% to ampicillin and 32.4% to tetracycline. Salmonella and E. coli strains were frequently resistant to ampicillin (12.5% and 47.7%, respectively) This study provides important information on the prevalence and antimicrobial resistance pattern of enteric pathogens in Dhahira region population. SXT, ampicillin, and tetracycline are the drugs commonly associated with resistance.

On December 26, 2003 an earthquake measuring 6.8 on the Richter scale, shook the city of Bam in the south east of Iran and killed more than 40000 people and nearly 30000 were injured. This is an epidemiological study performed on the victims of Bam earthquake to analyze different types of injuries of patients admitted in Kerman hospitals. In a retrospective cross-sectional study the medical records of 1250 victims of Bam earthquake admitted in Kerman hospitals from December 26, 2003 till 21 March, 2004 were reviewed and general demographic data such as age, sex, date of admission, type and anatomical site of injuries, diagnoses and complications were recorded. More than half of the patients were male. The mean age was 29.28±11.89 years. Lower limb injuries (40.8%) and pelvic injuries (26.2%) were the most common. The least common injury was chest injury (10.9%). More than 50% of pa tients had fractures. There were associations between chest injuries, vertebral column injuries and abdominal injuries and between vertebral column, chest and skull fractures. The numbers of injury and fracture locations for each patient were 0.186±0.11 and 0.0886±0.098, respectively. The study of individual factors and associations between different locations of injuries indicates a careful physical examinations and attention to special groups. It is important to use findings of epidemiologic studies on disasters to establish well-organized crisis registration system for the next disasters.

Chromium (Cr) is the most important element used to plate other metals and electroplating factories are still consid ered to be the most important industries which pollute the environment to this metal. This paper describes a study con ducted to determine the efficiency of reverse-osmosis (RO) as a membrane technique for removal of Cr from wastewater sam ples synthetically prepared to be similar to electroplating effluents. The RO unit used in this study was a spiral wound module of 2521 TE made by a Korean CSM company. Syn thetic wastewater samples containing Cr ions at various concentrations of 1 to 20 mg/L were prepared and subjected to treat ment by RO, and quantitative analysis had been accomplished by a colorimetric method. Evaluation of optimized condi tions of treatment had also been carried out by determining the effects of changing operating pressure, temperature and pHS of samples. Optimum conditions of Cr-treatment by RO in 10 g/L initial Cr concentration were determined to be in the pH range of 6 to 7 and in temperature of about 25ºC at an applied pressure of 200 psi. Considering the efficiency of Cr removal which was as high as 99% at the optimized conditions it could be con cluded that RO membrane process may be selected and developed as an effective alternative for treatment of metal-contami nated effluents of electroplating and similar industries.

Gastroesophageal reflux disease (GERD) is one of the most common gastrointestinal problems in the west while different reports indicate an increase in the prevalence in Iran. The aim of this study was to estimate the preva lence and clinical spectrum of GERD in staff of a referral hospital and evaluate the risk factors. This cross-sectional study using a modified Mayo clinic questionnaire was performed on staff of Imam Hospi tal, Tabriz, Iran on a pilot of 50 subjects, and a randomly selected group consisted of 522 subjects in the year 2005. GERD symptoms were defined as at least weekly heartburn and/or acid regurgitation during the past year. Response rate was 95%. Mean age of responders was 40.02±10.72 yr. The prevalence of recurrent heart burn and/or acid regurgitation experienced at least weekly and monthly was 26.8% and 34.1%, respectively. They were not related to age and gender. The severity of symptoms was mainly reported of a mild to moderate degree. 45% of the cases reported at least one of the atypical symptoms. There was no relation between marriage status and preva lence of GERD. On the other hand, GERD was less common among cases with no family history of upper gas trointestinal disease. The prevalence of frequent GERD was more common among medical staff. Increased BMI (but no recent weight gain or lose) was associated with higher prevalence of GERD symptoms only in women. In terestingly 33% of our population had a history of using antacid or PPIs which was more among cases with frequent GERD symptoms. This study revealed a high prevalence of frequent GERD symptoms in a selected population of Tabriz. Atypi cal symptoms should be considered in this area.

To determine prospectively the prevalence of anaerobic and aerobic infection in early onset (during 72 hours of age) neonatal sepsis, in Tehran Vali-e-Asr Hospital. Among all the live birth, neonates suspecting of having septicemia were investigated for isolation of micro organisms. Culture bottle containing enriched tryptic soy broth was used for standard blood culture system to detect aerobes and an ANAEROBIC/F bottle was inoculated using BACTEC 9120 continuous monitoring blood culture system to deter mine the growth of anaerobic bacteria. Among 1724 live births, 402 consecutive neonates suspecting of having septicemia were investigated for isolation of micro organism. A total of 27 episodes of early onset neonatal sepsis occurred with an incidence of 15.66 (11.6 aerobe + 4.0 anaer obe) per 1000 live births. Aerobic bacteria were the major etiological agents, accounting for 20 cases. 7 (26%) cases had posi tive blood cultures with anaerobic bacteria. Propionibacterium and Peptostreptococccus (amongst anaerobic) and coagu lase-negative staphylococci and staphylococcus aureus (amongst aerobic) were the most commonly isolated organisms. Compari son of clinical findings and demographic characteristics between aerobic and anaerobic infection did not have a signifi cant statistical difference. Our impression is that while anaerobic bacteremia in the newborn infants can occasionally cause severe morbid ity and mortality, majority of cases experience a self limited illness with transient bacteremia

Lymphadenitis is a common form of extra-pulmonary tuberculosis. As in peripheral health centers, the facili ties for histopathology and culture are lacking, material obtained by fine needle aspiration (FNA) in suspected cases of tubercu lar lymphadenitis (TBL) can be stained for Acid Fast Bacilli (AFB) by Ziehl Neelson method as every Designated Micros copy centre under Revised National Tuberculosis Control Programme has facility to perform it. This study was con ducted with the aim of establishing the utility of performing AFB on aspirated material at a DMC over performing cytology at a higher centre. Fifty eight suspected cases of TBL attending urban health training centre, Dept. of Community Medicine were in cluded in the study. FNA was performed and at least two slides were prepared, one for acid fast staining at centre itself and the other was sent for cytology, in the Dept. of Pathology. SPSS 11.0 was used to data analysis. 75.9% slides were AFB Positive; there was significant correlation of duration of disease and cytomorphology with AFB positivity. It was concluded that performing AFB staining at a peripheral centre on material aspirated from lymph nodes could alone be sufficient for diagnosis of tuberculosis in majority of cases

Human papillomavirus infection is one of the most common genital infections. More than 100 types of this virus have been identified, and most of them are capable of infecting the genital mucosa. Human papillomavirus is in association with cancerous and precancerous lesions of the cervix; some types like HPV 16 and 18 are highly carcinogenic, some types like HPV 31 and 33 are moderately and some types like HPV 6 and 11 are mildly carcinogenic. In this research, the relationship between cytological changes of the squamous epithelial cells and the presence of HPV infections in our cases has been assessed. In this prospective study, we collected 681 samples from women admitted to different hospitals and private gynecological clinics in Tehran, during the years 2003-2005. Two specimens were collected from each patient; one for a Pap smear study and the other for PCR assay in order to detect HPV. Out of our 681 samples, 600 specimens were suitable for PCR assay, and 34 cases were HPV positive in PCR assay. This means that 5.7 percent of our patients were infected with HPV. HPV infection is common in Iran and is nearly identical to European countries such as Germany, and Spain. Also, we found that using PCR assay in order to detect the presence of HPV viruses in vaginal discharges can be very helpful.

To perform a prospective case control study of blood stream infection to determine the infection rate of Acine tobac ter baumannii and the risk factors associated with mortality. From February 2004 to January 2005, 579 consecutive episodes of blood stream infection were obtained at two neo na tal intensive care units Al Nasser and Al Shifa hospitals in Gaza City. Forty (6.9%) isolates of A. baumannii were ob tained from the neonates under 28 d. Most of the isolates (92%) were from hospitalized patients in the intensive care units. Community acquired infection was 8%. Sixty three percent of the patients were males. The isolates of A. bauman nii were resistant to commonly used antibiotics while being sensitive to meropenem (92.5%), imipenem (90%), chloram pheni col (80%), ciprofloxacin (75%), gentamicin (57.5%), ceftriaxone (50%), amikacin (37.5%), cefuroxime and ce fo taxime (35%). Over all crude mortality rate was 20% with much higher crude mortality among patients with noso co mial infec tion. Based on logistic regression, the following factors were statistically significant: weight < 1500g, age < 7 d, mean of hospitalization equal 20 days, antibiotic use, and mechanical ventilation, when compared to the control group (P< 0.05). Infection rate of nosocomial blood stream infection was considerable and alarming in neonatal intensive care unit infants and associated with a significant excess length of NICU stay and a significant economic burden.

Trichomoniasis is an extremely common infection worldwide and is associated with important public health prob lems, including amplification of HIV transmission. This disease is in forms of symptomatic and asymptomatic in women and may depend on host as well as parasite variables. Thus the aim of this study was to evaluate the patients attend ing gynecology clinic with different symptoms and checked them for Trichomonas vaginalis infection. The vaginal secretion and urine samples of the patients attending gynecology clinic, Imam Reza Hospital, Amol City, were checked by direct smear and cultured in TYI-S-33 culture media. Out of 853 samples collected, 8(0.9%) were positive for T. vaginalis and the number of asymptomatic patients for tricho moniasis were 1.3 times more than infected samples belong to symptomatic ones. Per speculum examination revealed that 75% of T. vaginalis positive subjects had normal appearance of vagina and cervix. According to the epidemiological aspects, these asymptomatic patients are very important as healthy carriers, and T.vaginalis infections are commonly associated with other STDs and are a marker of high-risk sexual behavior. Thus laborato ries could play important role for diagnosis of infection and help the physicians for properly treatment.

The aim of study was to assess serum homocysteine and its relation with serum folate, vit B12 and lipid pro files in gestational diabetes mellitus and comparison with normal pregnant women as well as effect of different doses of fo lic acid on Homocysteine (Hcy) and pregnancy outcome. In a biphasic study first prospective controlled study 80 pregnant women were chosen at 24-28 weeks of gesta tion. In case group pregnant women with gestational diabetes mellitus and control group who had normal Oral Glucose Toler ance test (GTT) results. Levels of fasting glucose, homocysteine, vit B12, and folic acid, uric acid, total cholesterol, triglyc eride, LDL, HDL, were measured. In phase II study a randomized clinical trial was done with diabetic women 15 with 1mg folic acid and 15 with 5 mg folic acid for six weeks and then above variables and pregnancy outcome was evalu ated. The mean levels of homocysteine in Gestational Diabetes Mellitus (GDM) group were significantly higher but fo lic acid and vit B12 were significantly lower. Hcy levels were decreased in both groups after six weeks folic acid but de crease in Hcy for group 5mg was significantly more than 1mg group. Homocysteine levels were higher in GDM than normal pregnancy. High dose folic acid can reduce Hcy levels more than low dose and it may be a safe, simple, inexpensive intervention that prevents major pregnancy complications.

Enteroviruses can easily circulate in the population through sewage and they are suitable indicators for environ mental surveillance. On the other hand, in some countries there are evidences of silent circulation of viruses in sew age specimens despite no virus isolation from clinical specimens. Therefore, WHO has suggested environmental surveil lance using surface water and sewage specimens for final confirmation of Poliovirus eradication. In this research, according to wild Poliovirus circulation in Afghanistan and Pakistan and probability of virus entrance to Iran, and also to assure wild Poliovi rus eradication, the environmental surveillance was performed in Sistan and Balouchestan Province of Iran. From March 2004 to February 2005, 86 specimens from 2 sewage disposal systems, 5 hospitals and surface water from several villages were collected by Grab Sample method and tested for Enteroviruses directly and using 2 concentration meth ods: Pellet and Two-phase. Then Poliovirus and Non-Polio Enteroviruses (NPEV) were serotyped by microneutraliza tion method and Polioviruses were intratypically differentiated using ELISA and Probe Hybridization techniques. From a total of 86 specimens, Enteroviruses and Non-Polio Enteroviruses were isolated from 49(56.98%) and 46(53.49%) of specimens respectively. Polioviruses were isolated from 18(20.93%) specimens and none of them was wild Poliovi rus fortunately. 13(17.81%), 39(53.42%) and 57(78.08%) of enteroviruses were isolated using Direct, Pellet and Two-phase methods, respectively. The results of this research confirm the validity of environmental surveillance and Polio eradication in Sistan and Balouchestan Province.

Aspergillus flavus is the second most important Aspergillus species causing human infections particu larly fun gal sinusitis. Since little is known about aflatoxin producing ability of clinical isolates, this study was under taken to de tect the aflatoxigenic isolates amongst these isolates. A total of 23 isolates of A. spp. which were recovered from patients proved to have fungal sinusitis by morpho logi cal and histological methods and also 5 additional aflatoxigenic and non-aflatoxigenic reference of A. fla vus group strains were studied. The isolates were identified morphologically using Czapek Yeast Agar and A. flavus and parasiticus Agar (AFPA). Aflatoxin producing ability of the isolates was confirmed by Thin Layer Chromatogra phy. Existing of aflR gene the regulatory gene in aflatoxin biosynthesis, were studied in all isolates by PCR method. All twenty three Aspergillus isolates confirmed as A. flavus group by their macroscopic and microscopic fea tures. One clinical isolate confirmed as A. oryzae by mycological methods. A. oryzae as well as A. flavus JCM2061 and NCPF2008 and 3 clinical isolates were not able to produce orange pigment on AFPA. From total of 23 iso lates 4 (17.4%) con firmed to be aflatoxigenic by TLC method. A banding pattern which matched to aflR primers was amplified with approxi mate size of 800 bp in all 23 clinical A. flavus isolates. A larger banding pattern 1050 bp was revealed in clinical iso late; strain no.20 as well. Some clinical sinus isolates are able to produce aflatoxin and all of studied isolates including; A. oryzae, A. parasiti cus and A. sojae were able to amplify aflR gene under our laboratory conditions.

Crystalline silica may act as an immune adjuvant to increase inflammation and antibody production. The high est exposures to silica are known to occur in the dusty trades industries such as stone- cutting. We undertook this popula tion based study to examine the association between occupational silica exposure and humoral immune system. In this historical cohort study, 47 workers from 10 stone-cutting factories in Rey City, south of Tehran, Iran that had more than 10 years exposure to silica were included in case group and 45 individual without any exposure to silica were selected for control group. We measured serum immunoglobulins (IgM, IgG, and IgA) of participants with ELISA method and compared the results between exposed workers and control groups. The mean concentrations of two immunoglobulines (IgG, IgA) and IgM in case group in comparison with control group were higher and lower respectively but both were in normal range. IgA concentration between two groups was statisti cally significant (P< 0.05). Crystalline silica exposure may promote the humoral immune system in some individuals. Additional research is recommended in other population, using study design that minimize potential selection bias and maximize the quality of expo sure assessment.

To evaluate the prevalence of hepatitis C by antibody testing, HCV-RNA detection by PCR and relative risk fac tors of HCV infection among HD patients and staff members in Markazi Province/Iran. The other purpose was to deter mine genotypes of HCV in this population. The study group consisted of 204 HD patients and 47 staff members from all 9 dialysis centers in Markazi Prov ince, Iran. Anti-HCV antibodies were tested using a third generation ELISA and confirmed by RIBA. HCV RNA was deter mined by RT-PCR and genotyping was performed by a reverse hybridization assay (LiPA). The overall prevalence of HCV (HCV antibody and HCV-RNA) was 5.4%. Female sex (P= 0.019), duration of dialy sis (P= 0.003) and kidney transplant (P= 0.049) were significantly correlated with HCV infection. The predominant sub type was HCV-1a, detected in 4(50%) of the 8 HD patients. Genotype 4, 3a and 1b were found in 2(25%), 1(12.5%) and 1(12.5%) patients respectively. The prevalence of anti-HCV among staff members of HD units was 0%. The presence of anti HCV positive patients who had never been transfused, high prevalence of genotype 4 in this population, duration of HD as a risk factor for HCV positivity and non significant association between blood transfu sion and HCV infection suggest nosocomial transmission of the virus in dialysis units that needs to be confirmed by phyloge netic analysis of subgenomic regions of HCV. HD staff members dose not seem to be at increased risk of hepatitis C de spite the frequent blood exposure and lack of strict adherence to universal infection control precautions.