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.

[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.

[Comparison of different methods of hepatitis C virus genotyping]

In order to introduce the approach of HCV genotyping in our laboratory, a comparative study of 3 molecular and 1 serological methods, was conducted on 62 HCV RNA positive sera. The molecular genotyping methods target the 5'untranslated (UTR) region of the virus genome and are based on an amplification of the viral genome, followed by partial sequencing, analyses of restriction fragment length polymorphisms (RFLP) or molecular hybridation (Inno LiPA, Innogenetics). The serological method or serotyping is based on the detection of antibodies to genotype specific epitopes derivated from the Non Structural (NS) 4 region of the viral genome (HCV 1-6 Serotyping Assay, Murex Biotech). "In house" methods, sequencing and RFLP, identified the genotype for 13 samples classified as non-typables by commercial kits Inno LiPA test and HCV 1-6 Serotyping Assay. Mixed infections revealed, especially by Inno LiPA, could not be identified by partial sequencing, which seems to detect only predominant genotype. For 4 samples, genotyping results of the methods targeting the 5'UTR were discordant with those of the serotyping of the NS4 region. Commercial kits are efficient to determine HCV genotypes, particularly in the context of antiviral therapy and patient's follow-up, sequencing remains the best alternative for more complete characterisation of viral strains and for epidemiological investigations.

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.

[Combination of Emla cream and nitrous oxide for venous cannulation in children]

OBJECTIVE

To assess the efficacy of an combination of Emla cream and N2O for venous cannulation in children.

STUDY DESIGN

Prospective, randomized, double blind trial.

PATIENTS

The study included 75 unpremedicated children, aged 3 months to 5 years, ASA physical class I and II, undergoing an elective surgical procedure, randomized into three groups.

METHODS

In group I and III, children received Emla cream one hour before entering the theatre. In group II, children received a placebo. Children of group I and III also inhaled 50 vol% nitrous oxide in oxygen and those of groupe II 100 vol% oxygen, 3 min prior and during venous cannulation. A blinded observer recorded the following items: pain assessment with CHEOPS scoring, conditions of venous puncture and behaviour of children. Heart rate, blood pressure and oxygen saturation were assessed at three timepoints: before, 3 min after facial mask application and following venous cannulation.

RESULTS

There were non significant differences between the three groups for the conditions of venous cannulation. The CHEOPS score was better in group I (7[4-11]), compared to group II (10[6-13]; P < 0.01) and to group III (9[6-12]; P < 0.01).

CONCLUSION

Emla cream combined with nitrous oxide is effective for venous cannulation in providing satisfactory analgesia and in controlling anxiety elicited by the vision of needle.

[Fatal hepatitis in a young child: probable role of halothane]

A 3-year-old boy, who underwent multiple anaesthetics including halothane in a short period of time, developed 3 days after the last operation abdominal pain, jaundice and fever. Laboratory tests showed hepatic failure, with cytolysis, cholestasis and eosinophilia. Tests for hepatitis A, B, C, CMV and EBV were negative. No other causes of postoperative jaundice were identified. Despite symptomatic treatment, the child died 5 days after the last anaesthetic. Post mortem liver biopsy showed massive hepatic necrosis. The authors discuss factors increasing the risk for halothane-hepatitis, especially multiple exposures.

[Hemodynamic diagnosis of aortocaval fistula complicating abdominal aortic aneurysm]

A 78-year-old man with a history of hypertension was admitted for a fall with back pain. The blood pressure was at 110/50 mmHg and the pulse at 115 b.min-1. A pulsatile abdominal mass was palpated. No signs of respiratory insufficiency or congestive heart failure were found. The diagnosis of abdominal aortic aneurysm was promptly confirmed by echography. Before laparotomy, a pulmonary artery catheter was inserted for haemodynamic monitoring which showed a high cardiac output, low systemic vascular resistances, increased pulmonary artery wedge pressure and a high SvO2 (93%). This was not consistent with a hypovolaemic shock but rather an aortocaval fistula. After incision and aortic clamping, surgical procedure consisted of transaortic closure of the fistula and restoration of arterial continuity with a prosthetic graft. Initial control of venous bleeding was obtained by passing a Foley's catheter distally and by clamping the vena cava. The postoperative course was initially satisfactory. The patient was extubated, but remained with a major renal insufficiency. After a stay of 15 days in the intensive care unit, he died from nosocomial pneumonia. Aortocaval fistulas are either traumatic or spontaneous. Spontaneous fistulas are more common, and in about 90% of the cases result from a rupture of an atherosclerotic aortic aneurysm. Clinical findings include signs of high cardiac output symptoms of venous hypertension and regional arterial insufficiency. Haemodynamic changes can be of value for the recognition of an aortocaval fistula. Most authors emphasize the importance of preoperative diagnosis, allowing the use of appropriate operative techniques and a prompt control of the fistula. This could decrease haemodynamic instability and transfusion requirements.

[Pulmonary edema following laryngospasm in a child]

A case is reported of a pulmonary oedema secondary to a laryngospasm in a 10-year-old child during a scheduled orchidopexy. Anaesthesia was induced with 50% nitrous oxide in oxygen and halothane via a face mask. Pulmonary oedema occurred before the relief of the laryngospasm and its course was uneventful after tracheal intubation and mechanical ventilation with PEEP. Hydrostatic forces or an increased capillary permeability are likely causes of the oedema. The outcome is usually favourable.

[Caustic lesions of the upper digestive tract]

A study of 108 patients who had ingested variable quantities of a caustic substance, most often for suicidal reasons. Hydrochloric acid was the substance most often encountered After stabilisation of any hemodynamic and respiratory disorders, all patients received emergency endoscopy. Subsequent therapy was based on the following endoscopic findings: --Patients, in whom the mucosa was normal, were not hospitalised. --The digestive tract of patients with stage I disorders was rested for 10 days. --Patients with stage III, disorders were operated on as an emergency especially when signs of gravity were present. --Patients with stage II disorders constituted the group which posed most problems in our study. These patients required enteral feeding as soon as possible, via a simple jejunostomy.