Prevalence and risk factors of hepatitis B in Tunisia

Background

Hepatitis B virus (HBV) infection is a major public health problem. Data related to epidemiology, distributions and outcomes of VHB infections in Tunisia remains scarce. This work aimed to study the prevalence of HBV infections and their distribution as well as the main risk factors associated to HBV infection.

Methods

Our study was a cross-sectional household- based study carried out among a representative sample of 22 275 from January 2014 to December 2015. Sampling was based on the National Census of 2014. For data collection, questionnaires were administrated by trained investigator and blood samples were sent to the Reference laboratory for analysis of HBV markers.

Results

Among 21720 surveyed subjects, 19663 subjects had a laboratory tests and the serological results reached to 19155. Overall prevalence of HBs Ag was 1.7% [1.6-1.9]. Prevalence of HBsAg was significantly higher in men (2.1% against 1.4%; p < 10-3), in age group more than 20 years (2.1% against 0.1% p ≪10-3) and in the Central region (2.3%; p < 10-3). Among the associated risk factors in univariate analysis were chronic dialysis, dental care, surgical intervention, hospitalization, traditional circumcision, scarification and multiple sexual partners. Multivariate analysis showed that male gender, age over 20 years, center and south regions, hospital follow-up of a chronic pathology and having a family member chronic carrier of HBs Ag were the associated risk factors of HBV infection and vaccination was the only protective factor.

Conclusions

Our study allowed to have a clear estimate of the national prevalence of HBsAg and to classify Tunisia as a country of low endemicity of Hepatitis B. This decline is mainly due to the introduction of vaccination since 1995 and the improvement of the health system. However, more efforts should be paid to reduce nosocomial transmission and traditional high-risk behaviors.

Key messages

Tunisia has become a country of low endemicity for hepatitis B. This was a result to the introduction of vaccination since 1995.

Impact of hepatitis B vaccine in Tunisia 20 years after its introduction

Introduction

Vaccination against hepatitis B represents the most effective preventive measure to reduce the global impact of this infection. In Tunisia hepatitis B vaccination was introduced for health professionals in 1992 and for the general population in 1995. The objectives of this study were to evaluate the impact of vaccination twenty years after its introduction.

Methods

It was a descriptive study of data provided by the national survey of prevalence of Hepatitis B in Tunisia, which was a household-based study conducted in 2015. Blood samples sent to the reference laboratory to test markers of hepatitis B virus infection. The Vaccine effectiveness rate was calculated using the following formula: VE = 1 - Odds-ratio (OR), where OR = ratio of odds of being vaccinated among subjects with positive HBsAg test results to the odds of being vaccinated among subjects with negative HBsAg test results.

Results

Approximately a quarter of our population reported having been vaccinated against HBV, a coverage rate of 26.9%. Among subjects above 20 years of age, this rate was 85.3%. Besides, 83.7% of vaccinated subjects had received the three required doses of the HBV vaccine. Analysis of vaccination status by great regions of the country showed that the vaccination coverage rate was higher in the southern region. Regarding HBsAg prevalence, the rate was significantly higher among unvaccinated subjects 0.3% vs 2.2% in those vaccinated (OR = 0.11 [0.07-0.18]). We found that among vaccinated subjects, the serologic response rate at vaccination was only 63.2% which represented 16.2% of the total population. The vaccine effectiveness indicated that vaccination reduced by 88.6% the risk of HBV infection.

Conclusions

These results demonstrate that vaccination against hepatitis B introduced in the national immunization schedule since 1995 has reduced the infection although the vaccination coverage rate remains below 90%.

Key messages

Importance of vaccination that reduced by 88.6% the risk of HBV infection. More effort required to raise awareness about vaccination against HBV.

[Bacteriospermia: Effects on semen parameters]

OBJECTIVES

Bacteriospermia may result in male hypofertlity. Indeed, 60% of patients treated by Assisted Reproductive Techniques had a local infection or inflammation of genital tract. However, direct effects of bacteriospermia on semen parameters remain controversial. The aim of our work was to explore the effect of bacteriospermia on sperm parameters among patients consulting for hypofertility.

METHODS

A retrospective comparative study of two groups: a group of 70 patients with bacteriospermia (group 1) and a control group of 70 patients without bacteriospermia (group 2). For these groups, we studied the standard semen parameters (seminal volume and viscosity and spermatozoa count, initial and secondary mobility, vitality and morphology). Comparison of these parameters was made by the Chi² test and the Fisher test.

RESULTS

The mean age of our population was 40.4±6.7 years. There was no significant difference between ejaculate average volume in the 2 groups (group B: 2.78mL versus group A: 2.92mL with P=0.2). Similarly, for the viscosity no difference was noted (P=0,68). The altered parameters in the presence of bacteriospermia were mean concentration and sperm motility (P=0.001 and P=0.049 respectively). The prevalence of secondary asthenospermia was higher in the presence of bacterospermia (P=0.006). No statistically significant differences were observed for morphology and vitality of spermatozoa (P=0.276 and P=0.075 respectively). The leucospermia was associated with bacteriospermia in 10% patients. Ureaplasma urealyticum was the germ most found (45.7%) followed by Streptococcus and Staphylococcacae (20.3% for each), Gram negative rods accounted for 12.9%, while Corynebacterium spp was isolated only in 4,3% patients. U. urealyticum was associated with hypospermia in 33% of cases (P=0.031). Spermatozoa motility was significatively decreased not only in the presence of this bacteria (FT=0.002) but also when cultures were positive for Streptococcus (0.04) and Corynebacterium (P<0.001). Morphological abnormalities were also noticed with Streptococcus with index of teratozoospermia of 46% versus 19% in the 2nd group (P=0.046).

CONCLUSION

Bacteriospermia may impair sperm parameters. The treatment of this affection seems to improve sperm fertilizing potential. In addition, it could prevent contamination of culture media.

[Role of Toscana virus in meningo-encephalitis in Tunisia]

OBJECTIVES

To detect the presence of Toscana virus (TOSV) circulation in Tunisia and to study its role in viral meningo-encephalitis.

PATIENTS AND METHODS

A total of 315 (167 sera and 178 cerobrospinal fluid [CSF]) samples was investigated. These samples are colleted from Tunisian patients with neurological diseases during the period between January 2003 and December 2009. All samples were tested negative for enterovirus, Herpes Simplex virus and West Nile virus. Detection for IgM and IgG specific to TOSV was done by ELISA tests.

RESULTS

Specific IgM for TOSV were detected in 10 % of patients with neurological diseases (31 cases). These recent infections were distributed throughout the study period and predominated during summer and automn. Patients were originated, in the majority from the coastal region. IgG were isolated in 22 cases (7 %) corresponding to previous infection.

CONCLUSION

This is the first report of TOSV circulating in Tunisia and its frequent implication in neurological diseases. These results incited to include TOSV as one of the viral etiologies to target in the diagnosis of viral meningitis and encephalitis in the country.

[Second epidemic of West Nile virus meningoencephalitis in Tunisia]

The West Nile virus (WNV) re-emerged in Tunisia in 2003, causing an outbreak of meningoencephalitis.

OBJECTIVE

The authors studied the epidemiological, clinical, biological, and imaging features of WNV-associated neurological disease observed in central eastern Tunisia.

DESIGN

A retrospective descriptive study was made on patients with West Nile meningitis and/or encephalitis observed in the Sousse area, from August 15 to November 15, 2003. Screening for specific anti-WNV antibodies in serum was performed with Elisa.

RESULTS

Recent central nervous system infection due to WNV was confirmed in 21 patients with a mean age of 53 years and a sex ratio of 3.2. The clinical presentation was meningitis in 11 cases, meningoencephalitis in seven cases, and encephalitis in three cases. Patients with encephalitis were older than those with meningitis. An acute flaccid limb paralysis was observed in three patients. The CSF assay showed lymphocytosis, high protein (67 %), and normal glucose levels (83 %). Brain CT scan and MRI were normal. Three patients died, the remaining evolved uneventfully.

CONCLUSIONS

These first cases of WNV meningoencephalitis in Sousse area suggest a possibility of reemergence of this infection. Preventive measures and epidemiological surveillance are necessary.

[Risk of vertical transmission of hepatitis B virus in Tunisia]

The risk of vertical transmission of hepatitis B virus (HBV) varies with type of viral endemicity, degree of maternal infection and genomic characteristics of the virus. The aim of this study is to estimate this risk in Tunisia using serological and molecular methods to evaluate HBV replication, to determine viral genotypes and to detect presence of occult hepatitis in 2709 pregnant women. Serological markers were detected by ELISA methods, Genotype was determined by PCR-RFLP and occult hepatitis by nested-PCR. Four percent of women were positive for HBsAg; only 3% of them were also positive for HBeAg. Viral replication, over than 10(3) copies/ml, was detected in 61% of positive HBsAg patients. Three viral genotypes were detected: D (95%), B (3%) and A (3%). Occult hepatitis was detected in 4% of sera with "anti-HBc isolated" profile. In conclusion, the risk of vertical transmission of HBV exists in Tunisia. It increases by frequency of precore mutants, predominance of the genotype previously associated with high levels of replication and possibility of occult hepatitis B. These results show the importance of screening by serological HBV markers systematically during pregnancy with evaluation of viral replication in order to prevent vertical risk by efficient tools.

Association of interleukin-18 polymorphisms and plasma level with the outcome of chronic HCV infection

Hepatitis C virus (HCV) infection is the main cause of chronic liver disease throughout the world, and may progress to cirrhosis and hepatocellular carcinoma (HCC). Immunological factors, especially cytokines and some host genetic variations, rather than direct HCV action, seem to play an important role in the pathogenesis of HCV infection. Elevated levels of interleukin-18 (IL-18) were described previously for chronically (HCV)-infected patients. This study is aimed at investigating IL-18 promoter polymorphisms (-607C/A and -137G/C) in HCV-infected patients with different disease severities (chronic hepatitis C, liver cirrhosis and HCC) and establishing an association between these polymorphisms and IL-18 plasma concentration with the outcome of chronic HCV infection. The carriage of at least one C allele at position -607 (CC + CA) was associated with a higher risk of cirrhosis and HCC (P = 0.032). Compared with controls, HCV-infected patients had significantly higher levels of IL-18 (P = 0.0001) that correlate with disease severity (P = 0.01, P = 0.001, P = 0.0006, respectively). In conclusion, we supposed a possible implication of IL-18 promoter polymorphisms in the pathogenesis of chronic HCV infection.

Genetic features of polioviruses isolated in Tunisia, 1991-2006

BACKGROUND

Genetic characterisation of polioviruses remains highly important even in countries where wild poliovirus circulation has been interrupted. Sequence data on representative wild strains from all geographical regions is required for surveillance purposes and surveillance for vaccine-related isolates with increased potential for transmissibility in humans should continue.

OBJECTIVE

To report the genetic characteristics of wild and vaccine-related polioviruses isolated in Tunisia from 1991 to 2006.

STUDY DESIGN

Wild isolates were sequenced in the VP1 genomic region and compared to each other. Vaccine-related isolates were assessed for genetic recombination by PCR/RFLP and sequence analysis of the 3D region. Recombinant viruses were assessed for genetic drift in the VP1 region.

RESULTS

The VP1 sequences of the last wild isolates, all from serotype3, showed 97.7-98.7% nucleotide homology. Nineteen percent of vaccine-related isolates were vaccine/vaccine intertypic recombinants. No recombinant with non-poliovirus enteroviruses was identified. Mutational differences in the VP1 sequences of recombinant viruses ranged from 0.0% to 0.7% indicating a limited replication period.

CONCLUSIONS

This study provides sequence data on wild polioviruses from Tunisia/North Africa and shows that in countries with continuous high vaccine coverage transmission of vaccine-related polioviruses is time-limited.

Genomic stability prevails in North-African hepatocellular carcinomas

The molecular pathogenesis of hepatocellular carcinoma, a tumour characterized by a vast clinical heterogeneity, remains unexplored outside Europe and Eastern Asia. We analysed by direct sequencing or loss of heterozygosity assay, the common targets of genomic alterations in 42 hepatocellular carcinomas collected in western North-Africa. Overall, genomic instability was uncommon, allelic losses affecting mostly chromosomes 1p, 4q, 8p and 17p (24-28% of cases). CTNNB1 and TP53 were infrequently mutated (9 and 17% of cases, respectively). Surprisingly, TP53 mutation R249S, diagnostic of aflatoxin B1 exposure, usually frequent in Africa, was exceptional (one case), indicating that in western North-Africa, hepatocellular carcinoma genetics differs markedly from that of the remainder of the continent.

Molecular characterisation of a coxsackievirus A24 that caused an outbreak of acute haemorrhagic conjunctivitis, Tunisia 2003

This study reports the genetic characteristics of coxsackievirus A24 isolates from Tunisia, including a coxsackievirus A24 variant (CVA24v) that caused an outbreak of acute haemorrhagic conjunctivitis (AHC) between September and November 2003. The virus genome was detected by PCR from conjunctival swabs obtained from patients with AHC. Four virus isolates were obtained from PCR-positive samples and were serotyped by sequence analysis of the VP1 and VP4 genomic region and by seroneutralisation. Phylogenetic analysis of the VP1, VP4 and 3C genomic regions was performed. Other Tunisian CVA24 isolates from paralytic cases and healthy individuals were also amplified, sequenced and included in the phylogenetic analysis. The epidemic strain belonged to the CVA24 serotype. Phylogenetic analysis of the 3C region of the genome revealed a strong relationship between the Tunisian epidemic strain and strains that caused outbreaks in Korea (2002) and Guadeloupe and French Guiana (2003). Phylogenetic analysis of the VP1 and VP4 regions showed a clear distinction between serotype CVA24 isolates from conjunctivitis and non-conjunctivitis cases. This is the first study to report an outbreak of AHC caused by CVA24v in the North African region.

A case control study to assess risk factors for hepatitis C among a general population in a highly endemic area of northwest Tunisia

A matched case-control study was undertaken in 2004 in Béja, north-western Tunisia, to evaluate potential risk factors for hepatitis C infection. Cases were anti-HCV positive subjects screened in 1996 serosurvey. HCV seronegative controls (5 per case) were selected in the proximity of cases and matched for age and gender. A standardized questionnaire was used to collect demographic, socioeconomic, social behavior, medical and surgical history information. Matched odds ratios (OR) and adjusted OR (AOR) and their 95% CI were calculated in multivariate analysis using logistic regression. 57 HCV positive cases (mean age 61.63 +/- 14,84; 68.4 % female) and 285 HCV negative controls (mean age 60.95 +/- 14.66; 68.4 % female) were enrolled. Multivariate analysis revealed that intravenous drug injections (AOR=1.96; 95%CI[1.02-3.8] p=0.045), past history of invasive procedures (AOR=2.53; 95%CI[1.21-5.29] p=0.0014) and medical history of hypertension (AOR=2.31; 95%CI [1.17-4.56]p=0.015) were significantly associated to HCV infection. These results suggest that nosocomial transmission of HCV infection in north-west Tunisia is common.

[Identification of adenoviruses serotypes implicated in haemorrhagic conjunctivitis in Tunisia]

Human adenoviruses (ADV) are distributed worldwide; they are associated with a variety of diseases. Some ADV can be implicated in large epidemics of conjunctivitis, gastroenteritis and respiratory infections. Classical diagnosis of ADV infections is based on virus isolation on cell culture and identification of the serotype by neutralization test or hemagglutination inhibition assay. However, these methods have a lack of rapidity that makes them impractical in clinical situations. With the advent of PCR, the diagnosis of ADV was improved. In this work, we have used molecular techniques for the identification of ADV serotypes implicated in conjunctivitis in Tunisia. A total of 199 conjunctival swabs received between October 2000 and May 2005 were investigated. Serotype identification was performed using a PCR followed by restriction enzyme analysis in the hexon gene. Typing by sequencing of the PCR product was used to confirm the serotype identification. Among the 199 tested clinical specimens, 24% were positive for ADV. Two different profiles were observed: one predominant corresponding to the majority of the detected ADV; this profile is in favour of two distinct serotypes, ADV37 or ADV8; the second profile was specific of ADV4 and was found in one case observed in 2005. Sequencing confirmed two serotypes: ADV8 with an endemoepidemically circulation in our country and ADV4 that appeared sporadic. The present work showed the importance of molecular techniques not only for ADV detection but also for identification of the circulating serotypes. These techniques are practical and interesting mainly for the rapid virological investigation during epidemics.

Hepatitis B genotypes, precore and core promoter mutants circulating in Tunisia

Hepatitis B virus (HBV) is characterized by genetic heterogeneity, including genotypes and mutations. Eight genotypes (A-H) have been identified throughout the world with a characteristic geographical distribution. Previous studies also suggest that the viral genotypes may correlate with differences in clinical features of the infection. Two types of mutations were particularly described, precore and basal promoter mutations; they may play an important role in the clinical outcome of HBV infection. The aim of this study was to investigate the prevalence of HBV genotypes and HBV variants in Tunisia, and their eventual association with severity of liver disease. Using a molecular method, HBV genotypes, precore and basal core promoter mutations were determined in 56 asymptomatic carriers and in 82 patients with histologically verified chronic liver disease and hepatocellular carcinoma (HCC). Three genotypes (D, A, and E) were detected; the prevalence was 80%, 8%, and 9%, respectively. No significant difference was observed for genotype D with clinical status. HBV mutants were detected in 93% of cases, precore mutants were the most prevalent. Basal core promoter mutants were observed in 61% of cases, they were frequently characterized by a double mutation in 1762 and 1764. Co-infection by these two types of mutants was detected in 50% of cases. Genotype D was the most prevalent HBV genotype in Tunisia. High circulation of precore and basal core promoter mutants are common in chronic hepatitis B infection in Tunisia.

[Blood-transmitted viral infections among haemophiliacs in Tunisia]

In this work, we proposed to evaluate prevalences of hepatitis B and C viruses and Parvovirus B19 among 70 Tunisian haemophiliacs treated with clotting factors imported from Europe and/or locally produced cryoprecipitate; among them 6 (8.6%) are known HIV positive patients. HBs antigen, anti-HBc antibodies and anti-Parvovirus B19 antibodies were detected in 7.1%, 52.9% and 91.8%, respectively. HCV prevalence, defined as positive ELISA with positive Immunoblot and/or PCR was 50.0%. Prevalences of these viral infections in haemophiliacs are higher than prevalences detected among general population and in the control group of the study. HCV infection is less frequent in haemophiliacs born after 1985, the year of introduction of the inactivation procedures in the production of coagulation factors concentrates; it decreases more considerably after 1994, date of introduction of systematic screening of HCV among blood donors. In contrast, despite the inactivation of the factors concentrates and the systematic screening of the blood donations against HBs antigen, since 1973, the risk of HBV infection contamination remains high in the Tunisian haemophiliacs. The introduction in 1995 of hepatitis B vaccination in the national schedule of new-born vaccination may resolve in the future the problem of HBV infection in haemophiliacs and in the other categories of the Tunisian population.

Enteroviruses in Tunisia: virological surveillance over 12 years (1992-2003)

This report is an overview of enterovirus epidemiology in Tunisia during a 12-year period from 1992 to 2003. A total of 4700 clinical samples were collected as part of the national poliovirus surveillance programme and the routine diagnostic programme for aseptic meningitis. Enterovirus detection was performed by isolation on cell culture according to World Health Organization recommended protocols. Serotype identification was performed by seroneutralization of the cytopathic effect using pools of specific antisera and sequencing in the VP1 region of the genome. Poliovirus isolates were assessed for their wild or vaccine-related origin by standard World Health Organization recommended methods (PCR, probe hybridization and ELISA). The results confirm the interruption of wild poliovirus circulation since 1995. A total of 236 non-polio enterovirus (NPEV) strains were isolated; seroneutralization allowed typing of 93 % (219 out of 236) of them. The antisera used allowed the identification of the most common enterovirus serotypes. The remaining 17 isolates were sequenced; 16 of them belonged to enterovirus serotypes that were not targeted by the antisera pools used. A total of 29 different serotypes of NPEV were detected in the country during the study period. Echoviruses of serotypes 6, 11 and 30 were the most frequently isolated, almost every year; other serotypes had a cyclic occurrence and others were detected during a limited period with very few isolates. The NPEV isolation rate varied from year to year but was steadily under 10 %, suggesting a relatively low prevalence of these viruses in comparison to that in other developing countries. A seasonal variation was also noted; the high transmission period starts in March and peaks in September-November. This study is the first report of the epidemiology of NPEV in Tunisia. These viruses are associated with various diseases and epidemiological data may help to clarify their impact on human health.

Étude de l’infection par le virus de la rubéole chez l’enfant et l’adolescent en Tunisie

Rubella is a worlwide common infection; its importance in public health relates to the risk of malformation when primary infection occurs during pregnancy. This serosurvey was conducted to assess the kinetics of rubella infection in Tunisian children and teenagers and to determine the proportion of girls who remain seronegative at childbearing age. The studied population included 2481 individuals aged seven (N =1136), 13 (N =711) and 19 years (N =634), this sample was collected in 1996 and is representative of all geographical regions of the country. Our results indicate that 42% of tunisians are infected before seven years, 73% before 13 and 89% before 19 years of age. These rates are lower than those previously reported in the country. The proportion of seronegatives at 19 years of age was higher in costal regions than in the rest of the country: 14 vs 5% (p =0,0008). This difference should be due to the higher socio-economic level of the population living in costal regions. Our study indicates that primary infection with rubella virus in Tunisia is progressively shifting to older ages, which may increase the risk of congenital rubella syndrome. The introduction of rubella vaccination in the national program of vaccination may be considered, however only very high coverage levels will have a positive effect. Beside the reduction of the risk of congenital rubella syndrome, rubella vaccination will reduce the incidence of febrile rush cases and thus facilitate the surveillance activities conducted as part of the national program of measles elimination.

[Role of enteroviruses in aseptic meningitis in Tunisia]

Despite the favourable clinical outcome in most cases, viral meningitis can cause a serious public health problem especially when several cases occur during outbreaks. The first part of this work is a retrospective study conducted in three hospitals in Tunisia and covering a period of three years. It showed an incidence of viral meningitis 2.4. The second part of the study is a prospective one, it included 94 cases of aseptic meningitis notified during a period of 12 months. Virus isolation in cell culture was performed on CSF and stool samples, using cell lines sensitive to enteroviruses. A PCR to detect enteroviruses was also used in parallel. This study represents a first approach to viral meningitis in Tunisia. It highlights the importance of a regular surveillance of the disease and the contribution of molecular methods to a more sensitive diagnostic. However, cell culture remained necessary for viral isolation and serotyping.

Genotypes of hepatitis C virus circulating in Tunisia

Hepatitis C virus (HCV) isolates from 93 patients living in Tunisia, including 16 haemophiliacs, were genotyped by INNO LiPA and partial sequencing of the 5' untranslated region of the viral genome. In non-haemophiliacs, subtype 1b was largely predominant (79%), types 1a, 2a, 2b, 3a and 4a occurred much less frequently at 5, 7, 3, 3 and 1% of cases, respectively. In the group of haemophiliacs, a co-dominance between subtypes 1a and 1b was noticed (38%). Type distribution of HCV in Tunisia differs from that reported in other countries of the Mediterranean and Middle East regions. Genotyping results in respect of clinical status, age, and genotyping methods, are discussed.

[West Nile viral meningo-encephalitis in Tunisia]

In autumn 1997 an epidemic outbreak of meningoencephalitis was observed in two coastal districts of Tunisia. A total of 173 cases were recorded with 8 deaths. Detection with IgM capture and indirect IgG ELISAs demonstrated West Nile virus infection in 86% of patients from whom specimens were collected. West Nile is endemic in Asia and Sub-Saharan Africa. Epidemics in humans and horses have also been reported in the Mediterranean region and southern European countries. However this is the first report in Tunisia. Special West Nile virus surveillance is necessary especially in countries at high-risk for repeated introduction of this arbovirus.

Molecular epidemiology of poliovirus infection in Tunisia

This report is an overview of poliomyelitis surveillance in Tunisia from 1991 to 1996. In all, 2088 stool specimens, collected from 152 acute flaccid paralysis (AFP) cases and from 1747 of their healthy contacts were investigated. Virus isolation was done systematically in RD and HEp-2C cell lines and isolated viruses were typed by sero-neutralisation as polioviruses or non-polio enteroviruses. Poliovirus isolates were analysed systematically for their wild or vaccine-related origin by two methods--one based on antigenic differences and one on genetic differences between strains. All type 2 polioviruses were vaccine-related and most wild viruses belonged to polio serotype 3. Wild polio type 3 viruses were detected in 1991 and 1992 in six cases of paralytic polio. A silent circulation of wild polio 1 and wild polio 3 was detected in 1994. No wild virus was detected in Tunisia from 1995 onwards. Wild polioviruses were sequenced and compared with Tunisian wild strains isolated during the 1980s, as well as other genotypes from the international database. These investigations revealed a single Tunisian polio 3 genotype that has been circulating from 1985 to 1994 and two different polio 1 genotypes. These results reflect effective control strategies within the country and contribute to the improvement of the polio eradication programme effectiveness at national and global levels.