Distribution of G (VP7) and P (VP4) genotypes of group A bovine rotaviruses from Tunisian calves with diarrhoea.

AIMS: To investigate the incidence, viral load and genetic diversity of bovine rotaviruses strains in Tunisia. METHODS AND RESULTS: A total of 169 faecal specimens, collected from diarrhoeic calves from several farms located in the central eastern regions of Tunisia, between January 2006 and October 2010, were analysed by semi-nested multiplex RT-PCRs for P and G genotypes identification or were genotyped by DNA sequencing. Positive samples were tested by TaqMan real-time RT-PCR to quantify the viral load. Group A bovine rotaviruses were detected in 15·4% (26/169) of the total studied cases of diarrhoea. Overall, G10 was the predominant G type, detected in 12/26 samples (46·2%) and G6 accounted for 42·3% (11/26) while P[11] was the predominant P type, detected in 12/26 samples (46·2%). Two P[5] genotypes (7·7%) were found in the collection. Dual G or P combination and genotype G8 were not found. The most common VP7/VP4 combinations were G6P[11] (30·8%; n = 8) and G10P[11] (11·5%; n = 3). The combination G10P[14] was seen in one sample, and partial typing was assessed in 53·8% (n = 14) of the cases. The viral load determined by real-time RT-PCR showed an average of 1·68 × 10(9) genome copies/g of faeces. CONCLUSION: Knowledge of P and G types could help us understand the relatedness of animal rotaviruses to viruses causing disease in humans. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first time that the viral load and P types of bovine rotaviruses have been determined in Tunisia, and this study contributes to a better understanding of the epidemiology of such viruses circulating in Tunisia. Nevertheless, continuous surveillance is necessary to detect the emergence of new variants.

Detection of the human Parvovirus B19 in nonimmune hydrops fetalis using immunohistochemistry and nested-PCR in formalin-fixed and paraffin-embedded placenta and fetal tissues.

The aim of the present study was to determine whether there is an association between Parvovirus B19 infection and hydrops fetalis setting in fetus and neonate. Twenty-nine samples were analyzed by three methods. Each sample was histologically examined for viral nuclear inclusions in fetal organs and placenta, then immunohistochemical study using Parvovirus B19 antibody that recognized the VP2 protein of the Parvovirus B19 capsid was done in tissue embedded in paraffin (lungs, liver, thymus, kidneys, heart and placenta). Nested-PCR analysis was done after DNA extraction from paraffin blocks and using specific primers of the Parvovirus B19 VP1 gene. Apparent causes of hydrops were eliminated such as metabolic diseases, cardiac failure or malformation. The standard histological study objects viral inclusion in one case (lung tissue). However, the immunohistochemical study was negative in all cases. Nested-PCR demonstrates the presence of the viral DNA in five cases. Our study demonstrates that the implication of Parvovirus B19 in hydrops fetalis must be affirmed by the use of more than one method. Nested-PCR is the most sensitive method in our study and can be easily used for the detection of Parvovirus B19 in formalin-fixed paraffin-embedded tissues.

[Molecular phylogeny and genetic variability of echovirus 30 based on the analysis of the 3' end of the VP1 gene]. / Phylogénie moléculaire et variabilité génétique des échovirus 30 basées sur l'analyse de la région 3' terminale du gène VP1.

Echovirus 30 represent one of the most frequently isolated enterovirus serotype, incriminated in various pathologies, essentially aseptic meningitis. Several works studied the molecular epidemiology of these viruses. By analysing a region of 260 nucleotides situated in the end of the VP1 gene (region regrouping the majority of the sequences of the Echovirus 30), we proposed to realise a synthesis work which regroup the main epidemiological studies on the Echovirus 30. We established a phylogenetic profile of 87 Echovirus strains geographically distinct and isolated during a half a century (1957-2003). The phylogentic tree permitted to distinguish 2 genogroups which the nucleotide divergence exceeds 20%. The 2 genogroups also present internal subdivisions named genotypes which the nucleotide divergence is more than 15%. Finally, we noted phylogenetic regroupings within a same genotype. The general profile of the phylogenetic tree is characterised by a distribution of the Echovirus 30 strains in the time independently of their geographically isolation, which reveals a genetic evolution of these viruses related to their high genetic plasticity and the rapid circulation from a geographic area to another.

Molecular diversity of the aminoterminal region of the G protein gene of human respiratory syncytial virus subgroup B.

Two major antigenic subgroups (designated A and B) have been described for human respiratory syncytial virus (HRSV). Between and within the two main subgroups, there is antigenic variation in the attachment protein G. The variability of the G protein is known to be located in two hypervariable regions of the ectodomain. Most investigators have studied the gene segment coding the C-terminal end of the protein, and little is known about the N-terminal variable region. In the present study, the genetic variability of HRSV subgroup B was evaluated by nucleotide sequencing of the N-terminal region of the G gene of 52 Tunisian isolates. Tunisian subgroup B isolates clustered into two main lineages designated arbitrarily as Tu-GB1 and Tu-GB2. Three distinct subtypes were identified within genotype Tu-GB2. The inter- and intragenotype nucleotide variability ranged from 4 to 8% and from 0 to 4%, respectively. Overall divergence values of the G sequences were inferior or equal to 15% at the aminoacid level. Comparison of sequences among Tunisian HRSV strains and viruses isolated in other geographical areas during different epidemics demonstrated close similarity to strains from Kenya, Belgium, the UK, Qatar, Canada and South Korea.

[Genotypes of echovirus 6 in Monastir region]. / Génotypes d'échovirus 6 circulant dans la région de Monastir.

UNLABELLED: OBJECTIVE OF THE WORK: Echoviruses of serotype 6 were reported to be endemic in Tunisia and even in other country over the world. they are associated with many outbreak meningitis. The Objective of this study was to genetically characterize echovirus 6 fields isolates. It gives a first approach on the molecular epidemiology of this serotype. MATERIAL AND METHODS: Phylogenetic analysis of partial sequence in the 3'half of the VP1 region (2874-3529) from 25 strains of echovirus 6. RESULTS: 9 genotypes of echovirus 6 were individualized. Study area was Monastir, a touristic tunisian city. Strains were isolated from wastewater during one year, may correspond to three genotypes. CONCLUSION: Many genotype could circulating during the same time and in the same region. This phenomena was reported to be atypic in the case of poliovirus.