Serological, molecular characterization and epidemiological situation of equine influenza in the Arabic Maghreb countries between 1972 to 2010

AbstractEquine influenza is an infectious and contagious disease of horses. Studies on this topic are rare in the Maghreb countries. Therefore, the aim of this work is to present the various studies conducted on serological and molecular equine influenza virus since 1972 in the Maghreb region in particular in Morocco, Algeria and Tunisia.A total of four equine influenza strains were isolated in the Maghreb Arab region. A/equine/Nador/1/1997(H3N8), A/equine/Essaouira/2/2004(H3N8), A/equine/Essaouira/3/2004(H3N8) and A/equine/Algiers/1/1972(H3N8).The highest homology of HA nucleotide sequences of A/equine/Nador/1/1997(H3N8) with European strains: A/equine/Italy/1199/1992(H3N8) and A/equine/Brescia/1999(H3N8) clearly clustered A/equine/Nador/1/1997(H3N8) with the strains belonging to the European lineage. However, A/equine/Algiers/1/1972(H3N8), A/equine/Essaouira/2/2004(H3N8) and A/equine/Essaouira/3/2004(H3N8) were placed in the predivergent lineage indicating that like-Miami/63 strains infected equids in Morocco in 2004.This finding does not corroborate the recent studies of the H3N8 subtype of equine influenza viruses which have demonstrated that the oldest equine H3N8 strains, circulating before 1990 apparently went extinct

Phylodynamics and Human-Mediated Dispersal of a Zoonotic Virus

Understanding the role of humans in the dispersal of predominately animal pathogens is essential for their control. We used newly developed Bayesian phylogeographic methods to unravel the dynamics and determinants of the spread of dog rabies virus (RABV) in North Africa. Each of the countries studied exhibited largely disconnected spatial dynamics with major geo-political boundaries acting as barriers to gene flow. Road distances proved to be better predictors of the movement of dog RABV than accessibility or raw geographical distance, with occasional long distance and rapid spread within each of these countries. Using simulations that bridge phylodynamics and spatial epidemiology, we demonstrate that the contemporary viral distribution extends beyond that expected for RABV transmission in African dog populations. These results are strongly supportive of human-mediated dispersal, and demonstrate how an integrated phylogeographic approach will turn viral genetic data into a powerful asset for characterizing, predicting, and potentially controlling the spatial spread of pathogens

Diagnostic moléculaire par RT-PCR de la grippe équine au Maroc

Twenty-four nasopharyngeal swabs from suspect horses with equine influenza, taken from the Casablanca region, were analyzed by RT-PCR (Reverse Transcription Polymerase Chain Reaction) to research for the gene encoding the matrix protein M of equine influenza virus. The aim of this article is to check the specificity of each methods: RT-PCRq (real time) and conventional RT-PCR (classic), in order to confirm their correct application and comparison of their analytical sensitivity. The results of the sensitivity confirmed the high sensitivity of RT-PCRq detecting the virus diluting at 5.10.4 (viral charging: 150DCPE50/100μl), while the classical RT-PCR revealed a detection limit at the dilution 5.10-3 (viral Charging: 1,5.103DCPE50/100µl). Due to its high sensitivity, RT-PCRq was used to test the 24 swabs from horses with suspected equine influenza whose results were negative. However, the simultaneous amplification of a sequence of the gene Beta-actin specific equine increases the reliability of our results by the RT-PCRq inhibition control.Vingt quatre écouvillons naso-pharyngiens issus de chevaux suspects atteints de la grippe équine, prélevés dans la région de Casablanca, ont été analysés par la technique RT- PCR (Reverse transcription Polymerase Chain Reaction» pour la recherche du gène codant la protéine de la matrice M des virus d’influenza équins. L’objectif du présent article, est la vérification de la spécificité de deux méthodes RT-PCRq (= RT-PCR quantitative = RT-PCR en temps réel) et la RT-PCR conventionnelle ou classique dans le but de confirmer leur application correcte et la comparaison de  leur sensibilité analytique. Les résultats  de la sensibilité ont confirmé la haute sensibilité de la RT-PCR en temps réel détectant le virus porté à une dilution de 5.10-4 (Charge virale de 150DECP50/100μL), tandis que la PCR  classique, a révélé un seuil de détection au niveau de la dilution 5.10-3 (Charge virale de 1,5.103 DECP50/100μL). Vu sa haute sensibilité,  la RT-PCRq a été utilisée pour  tester les 24 prélèvements de chevaux  suspects atteints de la grippe équine  dont les résultats étaient négatifs.  Toutefois, l’amplification simultanée d’une séquence du gène Béta-actine spécifique des équidés augmente la fiabilité de nos résultats par un contrôle d’inhibition de la RT-PCRq

Évaluation de la primo- vaccination contre le virus influenza équin (H3N8) au Maroc

The present work is to evaluate the humoral response provided by two injections of primary vaccination (day 0 and day 28) recombinant vaccine in 31 seronegative equids against equine influenza (9 horses, 16 donkeys and 6 mules), of which eight sets of blood samples were performed weekly. After centrifugation, the sera obtained were analyzed by the hemagglutination inhibition test. The results of the follow of the variation in antibodies showed that the primary vaccination of recombinant vaccine provides a protective humoral response against equine influenza for the three species studied. The protective antibody levels well above the range of vaccine protection adopted by several authors (1 / 20, 1 / 40).  Antibody production exceeds the title of 1 / 20 (> 4log2) in less than a week and to the maximum immunity from the 14 to 21 day of the first injection of the primary vaccination. The mules have increased antibody titers of 2 log2 after the second injection. For all equines tested the antibody titer remained high two months after primary vaccination (1/64 or (8 log 2)).Le présent travail consiste à  évaluer la réponse humorale procurée par deux injections de primo-vaccination  (J0 et J28) d’un vaccin recombinant  chez 31 équidés séronégatifs pour la grippe équine (9 chevaux, 16 ânes et 6 mulets), sur lesquels  huit séries de prélèvements sanguins ont été réalisés. Les sérums ainsi obtenus sont analysés par le test d’inhibition de l’hémagglutination. Les résultats de la cinétique d’anticorps anti-hémagglutinine (H3) ont montré  que la primo-vaccination par le vaccin recombinant confère une réponse humorale protectrice contre la grippe équine pour les trois espèces étudiées, les titres d’anticorps protecteurs dépassent largement l’intervalle de protection vaccinale (1/20, 1/40). La production d’anticorps dépasse le titre de 1/20 (> 4log2) en moins d’une  semaine et l’immunité est obtenue à  son maximum à partir des 14 à 21 jours de la première injection de la primo-vaccination. Les mulets ont augmenté leurs titres en anticorps de 2 log2 après la deuxième injection. Pour l’ensemble des équidés testés le titre d’anticorps est maintenu élevé deux mois après la primo- vaccination (1/64 ou (8 log2))

Duration of Immunity Induced after Vaccination of Cattle with a Live Attenuated or Inactivated Lumpy Skin Disease Virus Vaccine

Vaccines have proven themselves as an efficient way to control and eradicate lumpy skin disease (LSD). In addition to the safety and efficacy aspects, it is important to know the duration for which the vaccines confer protective immunity, as this impacts the design of an efficient control and eradication program. We evaluated the duration of immunity induced by a live attenuated vaccine (LSDV LAV) and an inactivated vaccine (LSDV Inac), both based on LSDV. Cattle were vaccinated and challenged after 6, 12 and 18 months for LSDV LAV or after 6 and 12 months for the LSDV Inac. The LSDV LAV elicited a strong immune response and protection for up to 18 months, as no clinical signs or viremia could be observed after a viral LSDV challenge in any of the vaccinated animals. A good immune response and protection were similarly seen for the LSDV Inac after 6 months. However, two animals developed clinical signs and viremia when challenged after 12 months. In conclusion, our data support the annual booster vaccination when using the live attenuated vaccine, as recommended by the manufacturer, which could potentially even be prolonged. In contrast, a bi-annual vaccination seems necessary when using the inactivated vaccine

Susceptibility of Moroccan sheep and goat breeds to peste des petits ruminants virus

Abstract Background Peste des petits ruminants (PPR) is a highly contagious viral disease of small ruminants in Asia and Africa. In 2008, a PPR outbreak was reported for the first time in Morocco and a mass vaccination campaign allowed control of the disease. In this study, the susceptibility of four Moroccan local breeds of small ruminants to PPR virus was investigated by experimental infections. The objective was to make recommendations for improved epidemiological surveillance in Morocco by evaluating the susceptibility of the dominant Moroccan small ruminant breeds. Three parameters were studied: hyperthermia, clinical scoring and virus excretion. The outcome was compared to Alpine goats, which are considered one of the most sensitive breeds. Results The study showed that the local goat breed was the most sensitive breed with a susceptibility rate of 67%, followed by Timahdit, Beni Guil and Sardi sheep with 48, 29 and 26%, respectively. Serological testing including enzyme-linked immunosorbent assay and viral neutralization showed that the Timahdit breed developed a stronger antibody response compared to the other breeds. Although the clinical signs observed in the sheep were mild, evidence of viral excretion was detected by means of a polymerase chain reaction assay. Conclusions It is recommended that effective surveillance should focus on susceptible breeds complemented with serological surveillance of the sheep population