Intratumoral Canine Distemper Virus Infection Inhibits Tumor Growth by Modulation of the Tumor Microenvironment in a Murine Xenograft Model of Canine Histiocytic Sarcoma.

Histiocytic sarcomas refer to highly aggressive tumors with a poor prognosis that respond poorly to conventional treatment approaches. Oncolytic viruses, which have gained significant traction as a cancer therapy in recent decades, represent a promising option for treating histiocytic sarcomas through their replication and/or by modulating the tumor microenvironment. The live attenuated canine distemper virus (CDV) vaccine strain Onderstepoort represents an attractive candidate for oncolytic viral therapy. In the present study, oncolytic virotherapy with CDV was used to investigate the impact of this virus infection on tumor cell growth through direct oncolytic effects or by virus-mediated modulation of the tumor microenvironment with special emphasis on angiogenesis, expression of selected MMPs and TIMP-1 and tumor-associated macrophages in a murine xenograft model of canine histiocytic sarcoma. Treatment of mice with xenotransplanted canine histiocytic sarcomas using CDV induced overt retardation in tumor progression accompanied by necrosis of neoplastic cells, increased numbers of intratumoral macrophages, reduced angiogenesis and modulation of the expression of MMPs and TIMP-1. The present data suggest that CDV inhibits tumor growth in a multifactorial way, including direct cell lysis and reduction of angiogenesis and modulation of MMPs and their inhibitor TIMP-1, providing further support for the concept of its role in oncolytic therapies.

Detection of canine parvovirus type 2c (CPV-2c) in Palestine.

INTRODUCTION: The objective of the present study was to report, for the first time, the presence of canine parvovirus type 2c (CPV-2c) in domesticated dogs with acute gastroenteritis and to characterize the antigenic variants circulating in Palestine. METHODOLOGY: A veterinary clinical-based epidemiological study was carried out between December 2022 and April 2023. Fifty fecal samples were collected from dogs with gastroenteritis and screened for CPV-2 infection by polymerase chain reaction. The distribution of positive cases according to various epidemiological factors was studied. Partial sequencing of the viral protein 2 (VP2) gene was performed for the analysis of CPV-2 variants. RESULTS: Most of the investigated samples (60%; n = 50) during the study period were found positive for CPV-2 infection. There was no difference in the distribution of positive cases of CPV-2 infection based on age group, gender, location, and vaccination status. The analysis of nucleotide and amino acid sequences from amplified products, as well as phylogenetic analysis, revealed the presence of CPV-2c clustered with Asian CPV-2c variants. CONCLUSIONS: In summary, this study represents the initial genetic analysis of CPV-2 present in Palestinian dogs with gastroenteritis and provides evidence that confirms the existence of the CPV-2c variants. To determine the prevailing CPV-2 variant associated with the infection, it is crucial to conduct further sequence analysis using large populations of both domestic and wild canines.

Occurrence and phylogenetic analysis of fowl adenovirus E in broiler flocks from Gaza Strip Palestine.

INTRODUCTION: Inclusion-body hepatitis (IBH) and hydropericardium syndrome (HPS) are highly infectious diseases caused by fowl adenoviruses (FAdVs). IBH and HPS cause major economic losses in poultry production. IBH is caused by multiple FAdV serotypes such as FAdV-11, FAdV8a, and FAdV8b; while HPS is mainly caused by the FAdV-4 serotype. In 2018, we detected FAdVs in West Bank - Palestine for the first time. This study aims to monitor the emergence of new FAdVs in broiler farms in Gaza Strip-Palestine in 2022. METHODOLOGY: The clinical signs, necropsy, and histopathological findings associated with IBH in the suspected birds were recorded. Polymerase chain reaction (PCR) was performed using primers matching the virus-encoded L1 loop of the hexon gene. The sequences of the L1 loop were analyzed and a phylogenetic tree was constructed and compared with the related FAdV field isolates and reference strains from different regions of the world available in GenBank. RESULTS: The infected broiler displayed FAdVs-induced clinical symptoms and pathological lesions with mortality rates ranging from 20-46%. The L1 loop sequences from the infected flocks were submitted to GenBank with accession numbers ON638995, ON872150, and ON872151. The identified L1 loop gene has high nucleotide homology (96.7-97.9%) to the highly pathogenic FAdV E serotype 8b strain FAdV_isolate_04-53357-122_Canada_2007 (GenBank: EF685489) and 94.5-94.6% to FAdV_10_Belgium_2010 isolate 11-15941 (GenBank: AF339924.1). Furthermore, the phylogenetic analysis indicated that they belong to FAdV-E serotype 8b. CONCLUSIONS: Our study reports the emergence of FAdV-E causing IBH disease in broiler chickens for the first time in Gaza in Palestine.

First report of mobile colistin resistance gene mcr-1 in avian pathogenic Escherichia coli isolated from turkeys in the Gaza Strip, Palestine.

Background and Aim: Colistin is used to treat avian pathogenic Escherichia coli (APEC), a microorganism that affects turkey meat production in the Gaza Strip and worldwide. However, the recent emergence of plasmid-borne mobile colistin resistance (mcr) genes in pathogenic E. coli strains is a serious antimicrobial resistance (AMR) challenge for both human and animal health. In December 2018, colistin was banned as a veterinary antimicrobial in the Gaza Strip. This study aimed to detect and track the prevalence of colistin-resistant APEC isolated from turkey flocks in the Gaza Strip. Materials and Methods: This study investigated 239 APEC isolates from turkey flocks in the Gaza Strip between October 2018 and December 2021 (at 6-month intervals). The colistin-resistant APEC strains were detected using the broth microdilution method. The mcr-1 gene was identified using a polymerase chain reaction. Results: The overall colistin resistance among the isolated APECs was 32.2% during the study period. The average resistance in the first interval was 37.5%, which significantly decreased to 9.3% in the last interval. Among the 77 phenotypically resistant isolates, 32.4% were positive for mcr-1. The average abundance of mcr-1 in the first interval was 66.6%, which decreased to 25% in the last interval. Conclusion: To the best of our knowledge, this is the first study reporting the presence of the mcr-1 gene among the APEC isolates from turkeys in the Gaza Strip. Banned veterinary use of colistin significantly decreased the percentage of resistant APEC isolates from turkeys in Gaza Strip. Further studies are needed to investigate other colistin resistance genes and track the emergence of AMR.

The Impact of Thyme and Oregano Essential Oils Dietary Supplementation on Broiler Health, Growth Performance, and Prevalence of Growth-Related Breast Muscle Abnormalities.

The objective of this study was to investigate the effects of thyme and oregano essential oils (as growth promotors), individually and in combination, on the health, growth performance, and prevalence of muscle abnormalities in broiler chickens. Six hundred day-old Cobb 500 hybrid chickens were randomized into four dietary treatment groups with three replicates each. Chicks in the control group (C) received a basal diet, while the experimental treatment groups received basal diets containing 350 mg/kg of thyme oil (T1), 350 mg/kg of oregano oil (T2), and 350 mg/kg of thyme and oregano oil (T3). Growth performance parameters were evaluated at 14, 28, and 42 days. The broilers in treatments T1 and T2 had significantly higher body weights than the control group. The feed conversion ratio was the lowest in chicks who received oregano oil, followed by those fed thyme oil. The overall prevalence of growth-related breast muscle abnormalities (including white striping and white striping combined with wooden breast) in groups receiving essential oils (T1, T2, and T3) was significantly higher than in the control group (C). The thyme and oregano oil diets showed no significant differences in antibody titers against Newcastle disease or interferon-γ (INF-γ) serum levels. In conclusion, thyme and oregano oils had a positive impact on the growth performance of broiler chickens but increased the incidence of growth-related breast muscle abnormalities.

No evidence of Rift Valley fever antibodies in veterinarians and sheep in Northern Palestine.

Background and Aim: Rift Valley fever virus (RVFV) is a vector-borne virus that causes RVF in humans and ruminants. The clinical symptoms in humans and animals are non-specific and often misdiagnosed, but abortions in ruminants and high mortality in young animals are characteristic. Since the initial outbreak in the Rift Valley area in Kenya, the disease has spread to most African countries and the Middle East. The presence and epidemiological status of RVFV in humans and animals in Palestine are unknown. This study aimed to investigate the presence and risk factors for RVF seroprevalence in veterinarians, as occupational hazard professionals, and sheep, as highly susceptible animals, in Northern Palestine. Materials and Methods: A cross-sectional study was conducted. Data and blood samples of 280 Assaf sheep and 100 veterinarians in close occupational contact with sheep were collected between August and September 2020 using an indirect enzyme-linked immunosorbent assay. Results: No evidence of RVF antibodies was found in any human or animal sample. Conclusion: Our results suggest that RVFV has not circulated in livestock in Northern Palestine, yet. Surveillance and response capabilities and cooperation with the nearby endemic regions are recommended. The distribution of competent vectors in Palestine, associated with global climate change and the role of wild animals, might be a possible route for RVF spreading to Palestine from neighboring countries.

Phylogenetic analysis and pathological characterization of fowl adenovirus isolated during inclusion body hepatitis outbreak in Tubas, Palestine.

Fowl adenoviruses (FAdVs) associated with inclusion body hepatitis (IBH) was identified in commercial broiler chickens in Palestine. Investigated birds showed primary clinical signs and lesions of IBH including growth retardation, congested and enlarged liver with necrosis, petechial hemorrhage and basophilic intra-nuclear inclusion bodies. The mortality rate was from 15.00%. The FAdV was detected and sequenced in the liver samples of infected chicken by polymerase chain reaction using hexon gene-specific primers. Phylogenetic analysis revealed that FAdVs belong to FAdV-D serotype 10, clustered within the European highly pathogenic isolates. The highest nucleotide sequence similarity was 99.48% with highly pathogenic FAdV-D serotype 10 detected from infected chicken in Poland (GenBank: LN907532.1) and FAdV-D from infected chicken in Sweden (GenBank: HE961828.1). The lowest similarity was 93.46% with Canadian FAdV-D (GenBank: EF685576.1). In conclusion, this is the first report describing the presence of IBH revealing that the causative virus is closely similar to the highly pathogenic FAdV-D serotype 10 of IBH in broiler chickens in Palestine.

Seroprevalence and risk factors of West Nile virus infection in veterinarians and horses in Northern Palestine.

BACKGROUND AND AIM: West Nile fever (WNF) is a neurotropic, mosquito-borne disease affecting humans and domesticated animals, caused by a member of the genus Flavivirus. Over the last decades, this virus has been responsible for several cases of illness in humans and animals. The current epidemiological status of WNF in horses is insufficient, and in veterinarians, as an occupational hazard is unknown. This study aimed to investigate and determine the seroprevalence and risk factors for WNF in veterinarians and horses in Palestine. MATERIALS AND METHODS: In this study, serum samples from 100 veterinarians and 87 horses were collected between August 2020 and September 2020 from different cities of Northern Palestine. West Nile virus (WNV) antibodies were detected using an enzyme-linked immunosorbent assay. RESULTS: Our results showed that 60.9% of the horse serum samples were positive in all investigated cities. In horses, location is a risk factor for the seropositivity for WNF, whereas age, sex, breed, and intended use of the horses, were not associated with increased WNF seropositivity. In veterinarians, 23.0% of the serum samples were positive. Positive samples were detected in all locations, age groups, experience length, and work sectors. However, the seropositivity for WNF was not influenced by these variables. CONCLUSION: The results revealed that WNV circulates in most regions of Palestine. Our results will help determine the risk of infection in animals and humans and control WNV transmission. Surveillance studies on humans, vectors, and animals are needed to better define endemic areas.

A molecular and pathological study of peste des petits ruminants virus (PPRV) from field outbreaks in Palestine, 2017-2019.

Peste des petits ruminants (PPR) is a severe, highly contagious and fatal viral disease of small ruminants causing high economic losses. Therefore, the disease was targeted for eradication by 2030. The aim of this study was to investigate for the first time the molecular and pathological characterization of the circulating PPR virus (PPRV) in sheep and goat in Palestine. Samples were collected from suspected necropsy cases of sheep and goats during recent outbreaks in two provinces in Palestine between 2017 and 2019. In this study, severe PPR outbreaks occurred in sheep and goats causing typical lesions which include erosive and ulcerative stomatitis, bronchointerstitial pneumonia and severe enteritis. For the molecular investigation of PPRV, suspected animals were examined for the presence of PPRV by RT-PCR. PPRV genome was detected in all samples. Subsequently, two samples were used for N gene sequencing and phylogenetic analysis of PPRV isolates. The nucleotide sequence and phylogenetic analysis indicated that the Palestinian PPRV isolates were genetically clustered within the lineage IV isolates of the virus among populations of sheep and goats which most prevalent in Asia, the Middle East and recently Africa. Further analysis showed that the Palestinian isolates were closely related to those described in Turkey and Iraq, suggesting a common origin of PPRV isolates in the region. This information is critical to understand the molecular epidemiology of this disease in the region and helps to develop appropriate control measures for eradication of this disease.

Matrix metalloproteinases expression in spontaneous canine histiocytic sarcomas and its xenograft model.

Canine histiocytic sarcoma (HS) represents a malignant neoplastic disorder often with a rapid and progressive clinical course. A better understanding of the interaction between tumor cells and the local microenvironment may provide new insights into mechanisms of tumor growth and metastasis. The influence of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) on tumor angiogenesis, invasion and metastasis has been detailed in previous studies. In addition, inflammatory cells infiltrating neoplasms especially tumor associated macrophages (TAM) may contribute significantly to tumor progression. Due to the high variability of spontaneously occurring canine HS, standardized models are highly required to investigate tumor progression and interaction with its microenvironment. Therefore, the present study comparatively characterized the intratumoral macrophage infiltration as well as the expression of MMP-2, MMP-9, MMP-14 and TIMP-1 in spontaneous canine HS and its murine model. In spontaneous canine HS, scattered MAC 387-positive macrophages were randomly found in tumor center and periphery, whereas tumor cells were negative for this marker. Interestingly, quantitative analysis revealed that MMPs and TIMP-1 were mainly expressed at the invasive front while tumor centers exhibited significantly reduced immunoreactivity. Similar findings were obtained in xenotransplanted HS. Interestingly, murine tumor associated macrophages (TAM), characterized by Mac3 expression (CD107b/LAMP2), which was not present in xenotransplanted histiocytic sarcoma cells, strongly express MMPs and TIMP-1. In addition, MMPs are known to regulate angiogenesis and a positive correlation between MMP-14 expression and microvessel density was demonstrated in xenotransplanted histiocytic sarcomas. Summarized similar findings with respect to MMP and TIMP distribution and the role of macrophages in spontaneously-occurring and xenotransplanted HS indicate the high suitability of this murine model to further investigate HS under standardized conditions. Moreover results indicate that MMP expression contributes to tumor progression and invasion and TAMs seem to be major players in the interaction between neoplastic cells, the microenvironment and vessel formation indicating that therapeutic approaches modulating TAM associated molecules might represent promising future treatment options.