Pathogenicity of field strain of fowl aviadenovirus serotype 11 isolated from chickens with inclusion body hepatitis in Morocco.

Outbreaks of inclusion body hepatitis have emerged in Morocco since 2013 and has resulted in significant economic losses to poultry farms. Three isolates of the causative virus, Fowl adenonovirus (FAdV)were characterized from chickens with IBH, but their pathogenicity has never been investigated. In this work, the pathogenicity of an isolate FAdV 11 (MOR300315 strain) was evaluated by inoculating a group of 40 SPF chickens at 3 days of age by oral route. A group of 40 chicks injected with phosphate-buffered saline solution was used as a control group. The infected chickens showed decreased weight gain from 3dpi. Necropsy displayed pallor and enlargement in liver, swelling and slight hemorrhage in kidney and spleen at 6 dpi. Histopathological changes were mainly characterized by severe and extensive hepatic necrosis associated with the presence of basophilic intra-nuclear inclusion bodies within hepatocytes. The FAdV was reisolated in chicken embryo fibroblast cell culture from liver tissue homogenate of infected chicken from 3 to 6 dpi. Viral DNA was detected by PCR in liver, kidney, spleen and cloacal swabs from 3 to 13 dpi. Antibody response against inoculated FAdV was appeared from 9 dpi. These results confirmed that the FAdV 11 strain is pathogenic in chicken. This study is the first experimental infection of FAdV 11 in chicken in Morocco, which increase our understanding of its pathogenicity in chickens and indicate that preventive measures against FAdV infection in poultry farms should be implemented in Morocco.

External quality assessment of Rift Valley fever diagnosis in countries at risk of the disease: African, Indian Ocean and Middle-East regions.

Rift Valley fever virus (RVFV), an arbovirus belonging to the Phlebovirus genus of the Phenuiviridae family, causes the zoonotic and mosquito-borne RVF. The virus, which primarily affects livestock (ruminants and camels) and humans, is at the origin of recent major outbreaks across the African continent (Mauritania, Libya, Sudan), and in the South-Western Indian Ocean (SWIO) islands (Mayotte). In order to be better prepared for upcoming outbreaks, to predict its introduction in RVFV unscathed countries, and to run efficient surveillance programmes, the priority is harmonising and improving the diagnostic capacity of endemic countries and/or countries considered to be at risk of RVF. A serological inter-laboratory proficiency test (PT) was implemented to assess the capacity of veterinary laboratories to detect antibodies against RVFV. A total of 18 laboratories in 13 countries in the Middle East, North Africa, South Africa, and the Indian Ocean participated in the initiative. Two commercial kits and two in-house serological assays for the detection of RVFV specific IgG antibodies were tested. Sixteen of the 18 participating laboratories (88.9%) used commercial kits, the analytical performance of test sensitivity and specificity based on the seroneutralisation test considered as the reference was 100%. The results obtained by the laboratories which used the in-house assay were correct in only one of the two criteria (either sensitivity or specificity). In conclusion, most of the laboratories performed well in detecting RVFV specific IgG antibodies and can therefore be considered to be prepared. Three laboratories in three countries need to improve their detection capacities. Our study demonstrates the importance of conducting regular proficiency tests to evaluate the level of preparedness of countries and of building a network of competent laboratories in terms of laboratory diagnosis to better face future emerging diseases in emergency conditions.

Using geostatistics to better understand the epidemiology of animal rabies in Morocco: what is the contribution of the predictive value?

This study aims to characterize the spatial distribution of animal rabies in Morocco in order to provide appropriate control approaches. Descriptive analyses of the epidemiological data show that the number of reported canine rabies cases greatly underestimates the true incidence of the disease. Underreporting subsequently affects the coherence of its spatial distribution. To perform accurate geographic distribution mapping of the disease based on interpolation methods, a data set was created using data between 2000 and 2018 to compare the derived disease cases with known true values in order to identify disease clusters. The subsequent interpolation was conducted using Ordinary Kriging regression methods and the semi variogram to focus on short distances and reduce uncertainty. The estimated clusters of rabies were evaluated using a cross validation step which revealed predicted cases close to the true values. To improve the precision of analysis, the authors displayed georeferenced dog and human rabies cases reported during the last three years, demonstrating reliable results that correspond to the estimated cluster areas similar to the true disease incidence on the field. This work highlights a strong correlation between infrastructure projects (i.e. railways, roads, facilities) and rabies epizootics for several specific locations. This study is the first attempt to use geostatistics to build upon the understanding of animal rabies in Morocco and shed light on the most appropriate strategies to sustainably reduce and mitigate the risk of rabies. There has been little literature on the use of kriging methods in animal health research. Thus, this study also aimed to explore a novel method in the veterinary sciences to establish kriging as a valid and coherent analysis tool to identify the extent to which the geostatistic area can objectively support understanding on animal rabies and saw it as being highly instrumental in coping with gaps in the data.

Isolation and characterization of fowl aviadenovirus serotype 11 from chickens with inclusion body hepatitis in Morocco.

The present study was conducted in order to isolate, identify and characterize fowl aviadenovirus associated with inclusion body hepatitis (IBH) in three poultry farms (two of broiler chickens and one of breeder broiler chickens) in Morocco during 2015. Liver samples collected from affected three poultry farms were examined by histopathological examination. Tissue samples showing necrosis of hepatocytes associated with basophilic intranuclear inclusion bodies were homogenized and submitted to FAdV isolation in chicken embryo fibroblast (CEF) cell cultures and in SPF embryonated eggs. The cytopathic effect (CPE) was observed in the second passage with swelling and rounding of infected cells. The inoculated embryos were hemorrhagic and showed hepatitis with the presence of basophilic intra-nuclear inclusion bodies within hepatocytes. The presence of the virus was confirmed by conventional polymerase chain reaction based on hexon gene from all investigated samples. Moreover, phylogenetic analysis of the hexon gene revealed that FAdVs isolated from different affected poultry belonged to FAdV 11 serotype of the D genotype group. This work is the first isolation in cell culture and SPF embryonated eggs of FAdV from Moroccan broilers and breeder broiler chickens with IBH.

Molecular epidemiology of canine parvovirus in Morocco.

Since it first emergence in the mid-1970's, canine parvovirus 2 (CPV-2) has evolved giving rise to new antigenic variants termed CPV-2a, CPV-2b and CPV-2c, which have completely replaced the original strain and had been variously distributed worldwide. In Africa limited data are available on epidemiological prevalence of these new types. Hence, the aim of the present study was to determine circulating variants in Morocco. Through TaqMan-based real-time PCR assay, 91 samples, collected from symptomatic dogs originating from various cities between 2011 and 2015, were diagnosed. Positive specimens were characterised by means of minor groove binder (MGB) probe PCR. The results showed that all samples but one (98.9%) were CPV positive, of which 1 (1.1%) was characterised as CPV-2a, 43 (47.7%) as CPV-2b and 39 (43.3%) as CPV-2c. Interestingly, a co-infection with CPV-2b and CPV-2c was detected in 4 (4.4%) samples and 3 (3.3%) samples were not characterised. Sequencing of the full VP2 gene revealed these 3 uncharacterised strains as CPV-2c, displaying a change G4068A responsible for the replacement of aspartic acid with asparagine at residue 427, impacting the MGB probe binding. In this work we provide a better understanding of the current status of prevailing CPV strains in northern Africa.

A sheeppox outbreak in Morocco: isolation and identification of virus responsible for the new clinical form of disease.

BACKGROUND: Sheeppoxvirus (SPPV) is a member of the Capripoxvirus genus of the Poxviridae family, which causes significant economic losses in Morocco. The resurgence of the sheeppox disease during 2010 was characterized by an emergence of a classical nodular form for the first time in Morocco. However, little is known about the virus strain responsible for nodular form. In this study, thirty three sheep, from the eastern region of Morocco, clinically infected were examined and dead animals were autopsied.A rapid diagnostic assay for SPPV using different type of clinical samples would be useful for outbreak management. The aim of this work was to isolate the virus strain responsible for nodular form and we identified and compared by phylogenetic analysis the field strain with Moroccan vaccine strain targeting the thymidine kinase (TK) gene and the chemokine analogue receptor of interleukin (IL8) gene. Further, it was important to investigate and validate a real-time PCR using different clinical and post-mortem samples to manage epidemic sheeppox disease. RESULTS: The nodular form of sheeppox disease observed in Morocco was clinically characterized by fever, depression, lacrimation, diarrhea in lambs and nodule. At necropsy, the most affected organ was the lung. The etiological strain was successfully isolated from lung nodule in a dead lamb and was identified by using real-time PCR that has been tested and validated on different types of clinical and post mortem samples from naturally infected animals. Sequence and phylogenetic analysis of TK and IL8 gene showed that there was a very close relationship between field and vaccine strain. They were clustered within other SPPV strains. CONCLUSION: In the current study, we show for the first time the nodular form of sheeppox in Morocco. We demonstrate a robust real-time PCR-based diagnostic assay to detect the sheeppox virus in multiple sample that can be implemented to efficiently manage the disease outbreak. Our study also offers the prospect for future molecular studies to understand the clinical forms.