Central-eastern Tunisia Research Articles

Combination of morphological and molecular markers for the characterization of ancient native olive accessions in Central-Eastern Tunisia

Increasing olive germplasm erosion in the coastline of Tunisia has required an imperious conservation of the traditional genotypes before an ultimate disappearance. This region has been relatively neglected in the literature sources of olive identification. In this context, a prospection effort and a preliminary selection of olive accessions belonging to Central-Eastern Tunisia was carried out. Twenty-seven ancient olive accessions were studied by combining molecular and morphological data in order to fingerprint them, and to evaluate their relationships with classical cultivars. Compared to known classic Tunisian olive cultivars, the new prospected olive accessions were well distinguished, presenting a potential use as promising genotypes. The morphological and molecular data showed a high diversity between genotypes. 92 and 63 polymorphic bands were scored using 10 RAPD and 9 SSR markers, respectively. Significant correlation coefficients were obtained among fruit and stone sizes (r=0.90) and among their shapes (r=0.73). The genetic distances obtained with the two DNA marker systems were significantly correlated (r=0.45) according to Mantel's test. No significant correlation was observed between distances based on molecular and morphological markers. UPGMA analysis based on molecular data showed no clear clustering trends according to morphological traits or fruit use. Despite the high genetic variation among accessions in each prospected area, geographical origin seemed to have significant impact on the observed variability. The relationship between morphological and molecular data has confirmed that each marker expressed different aspects of variability. Integration between all markers will be useful for distinguishing new accessions and genotyping local varieties.

A mixed methods study of ruminant brucellosis in central-eastern Tunisia.

In this study, we conducted an investigation to determine the true prevalence of bovine and ovine brucellosis in central-eastern Tunisia. A total of 1134 veterinary samples taken from 130 ruminant herds were screened for brucellosis using IS711-based real-time PCR assay. Sera collected from the ruminants were tested using the Rose Bengal test and indirect enzyme-linked immunosorbent assay. Based on serological and molecular results, the true adjusted animal population level prevalence was 23.5% in cattle, against 13.5% in sheep. In addition, the true adjusted herd level prevalence of brucellosis was 55.6% in cattle and 21.8% in sheep. A statistically significant association was found between vaginal and milk shedding for ruminants. In addition, our results showed that Brucella abortus could be responsible for bovine and ovine brucellosis. Multivariable logistic regression analysis at the animal population level indicated that age and origin variables were important risk factors for cattle. However, age and abortion variables were found to be associated with ovine brucellosis. At the herd level, risk factors for Brucella positivity were as follows: abortion and herd composition for cattle against herd composition, mortality rates, and hygiene for sheep. Animal hygiene, food quality, and sanitary practices on the farm should be applied as strategies to control brucellosis in herds.

Molecular prevalence of bovine noroviruses and neboviruses detected in central-eastern Tunisia

Two genetically distinct bovine enteric caliciviruses are known: noroviruses of genogroup III (NoVsGIII), which are genetically related to human noroviruses, and neboviruses, which represent a new calicivirus genus. To investigate the presence of NoVsGIII and nebovirus strains in diarrheic calves in Tunisia, a total of 169 faecal specimens were collected from January 2006 to October 2010 from different cattle herds located in the central-east regions. RT-PCRs and sequencing were carried out using primers targeting the 3' end of the polymerase gene of NoVsGIII and neboviruses. This study revealed that NoVsGIII and nebovirus are endemic in diarrheic calves in Tunisia. NoVsGIII infections, all with genotype 2, had an apparent molecular prevalence of 16.6 % and were more frequent than nebovirus infections. NoVsGIII infections showed clear seasonality, with a peak in winter. Nebovirus infections, with a prevalence of 3.0 %, were all related to the reference strain Bo/Nebraska/80/US.

Une deuxième épidémie de méningo-encéphalite à virus West Nile en Tunisie

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. Preventives measures and epidemiological surveillance are necessary.