The Coronaviruses of Animals and Birds: Their Zoonosis, Vaccines, and Models for SARS-CoV and SARS-CoV2.

The viruses of the family Coronaviridae are ubiquitous in nature due to their existence in a wide spectrum of mammals and avian species. The coronaviruses, as RNA viruses, exist as quasispecies because of their high rate of mutations. This review elaborates on the pathogenesis and the developed vaccines of most of the ubiquitous coronavirus' diseases, mainly bovine, dromedary camel, porcine, feline, canine, and avian coronaviruses. The review emphasizes the significant setbacks in the full exploitation of most of the pathogenesis of the coronavirus' diseases, raising the prospect of effective vaccines for these diseases. The therapeutical trials for the treatment of SARS-CoV2 and the setbacks of these trials are also addressed. The review draws attention to the lessons accumulated from the large number of studies of the pathogenesis of animals and birds' coronaviruses and their vaccines, particularly the bovine, feline, and avian coronaviruses. The lessons drawn from the studies will have an immense influence on how the human coronaviruses pathogenesis and vaccine development will proceed. In addition, the extensive efforts to designate suitable animal models to study the lately emerged human coronaviruses are one of the invaluable contributions carried out by veterinarian scientists. Finally, factors and determinants that contribute to the possibility of emerging new coronavirus zoonotic disease are elaborated on and a call goes out to urge transdisciplinary collaboration in the implementation of the "One Health" concept.

Investigation of Mycobacterium paratuberculosis in Arabian dromedary camels (Camelus dromedarius).

AIM: Mycobacterium avium subspecies paratuberculosis (MAP) causes Johne's disease in ruminants. This study aimed to investigate Mycobacterium paratuberculosis infection in clinically infected camels on the immunological, conventional bacteriological, and molecular biological basis. MATERIALS AND METHODS: A total of 30 Arabian camels (Camelus dromedarius) were examined in this study. The camels were suffering from signs ranging from mild to severe infections (that did not respond to antibiotic treatment) to chronic or intermittent diarrhea. Camels were grouped into three groups based on their age, sex, and breed. Detection of anti-MAP antibodies in camels' serum, Ziehl-Neelsen (ZN) staining technique on rectal scraps, direct recognition of MAP in stool and tissue specimens by IS900 polymerase chain reaction (PCR) assay, and finally isolation and molecular description of MAP from fecal and tissue samples were carried out. RESULTS: Five MAP isolates were recovered from these investigated camel samples giving an isolation rate of 16.6%, while eight camels were identified by PCR (26.6%). Five camels yielded MAP in their feces by ZN fecal staining (16.6%), whereas ELISA detected anti-MAP antibodies in nine camels only (30%). CONCLUSION: From the obtained results, we concluded that the gold standard for the diagnosis of MAP is the culture method despite its limitations. Molecular diagnosis (PCR) could be a useful tool in the identification of truly positive and negative camels; however, great care should be given regarding the primers specificity and sensitivity.

Reactivity of commercially available monoclonal antibodies to human CD antigens with peripheral blood leucocytes of dromedary camels (Camelus dromedarius).

Monoclonal antibodies (mAbs) to cell surface molecules have been proven as a key tool for phenotypic and functional characterization of the cellular immune response. One of the major difficulties in studying camel cellular immunity consists in the lack of mAbs that dtect their leukocyte differentiation antigens. In the present study two-parameter flow cytometry was used to screen existing commercially available mAbs to human leukocyte antigens and major histocompatibility molecules (MHC) for their reactivity with camel leukocytes. The comparison of patterns of reactivity obtained after labelling human and camel leukocytes have shown that mAbs specific to human cluster of differentiation (CD) 18, CD11a, CD11b and CD14 are predicted to be cross-reactive with homologous camel antigens.

The CD markers of camel (Camelus dromedarius) milk cells during mastitis: the LPAM-1 expression is an indication of possible mucosal nature of the cellular trafficking.

Studying the cellular populations of the camel mammary glands through the expression pattern of the CD markers and adhesion molecules is a mean to define whether the cellular trafficking pathway is peripheral or mucosal nature. Camel milk cells from 8 Gram-positive and 5 Gram-negative infected camels were examined with flow cytometry using cross-reacting antibodies like, anti-CD4(+), CD8(+), WC+1(+)γδ, CD62L, CD11a(+)/CD18, LPAM-1, CXCR2. The overall results indicated high flow cytometry output of most of the CD makers. The statistical analysis of the mean percentage of the expressed CD markers has shown that CD62L, CXCR-2, LPAM-1, CD11a/CD18, CD8(+), IL-6R and CD20(+) were expressed in significant differences in either type of the infection. The LPAM-1 expression has provided further support to the notion that the lymphocyte trafficking is of the mucosal nature. The mucosal origin of cellular trafficking has important implications on the vaccine design and therapeutical approaches to mastitis.

The gammadelta cells as marker of non-seroconverted cattle naturally infected with Mycobacterium avium subspecies paratuberculosis.

Early diagnosis of MAP infection is a pressing need to enable efficient intervention with the spread of MAP infection in herds. Hence, study of lymphocyte subsets and their expressed adhesion molecules could contribute in defining a distinct diagnostic marker (or markers) at the subclinical period of the infection that could in turn facilitate the development of effective diagnostic approach. In accordance with this objective, milk and blood samples were collected from two groups of cattle naturally infected with MAP and their corresponding negative controls. Group (C) comprised 3-4 year-old ELISA negative/PCR positive-cattle that were considered as subclinical seronegative low shedder group (early stage). Group (A) included 6-8 year-old ELISA positive-cattle, which were considered as a clinical seropositive group (late stage). Flow cytometry of B cells, CD8(+), CD4(+) and gammadelta cells and the adhesion molecules CD44(+), CD62L, LFA-1 and LPAM-1 indicated increase in CD4(+) and B cells levels, with higher levels in blood than milk of group A, and significant expression of CD44(+) in blood and milk and LPAM-1 in blood only. The CD8(+) cells count in milk was higher than blood in the late stage. The peculiar feature of the early stage (group C) was the high level of gammadelta cells in the blood and milk, with tendency to express high level of CD62L. Compelling evidence could support the assumption that the dominant gammadelta cells at early stage of MAP infection could be of CD8CD2(-)WC+1(+) phenotype. gammadelta cells appear as promising markers in defining early changes of MAP infection due to their important role in priming innate and cell mediated immunity. Possible utilization of these peculiar changes in the gammadelta cells level in the early diagnosis of MAP infection should be the subject of further research.

The etiology of Mycobacterium avium subspecies paratuberculosis in Crohn's disease.

The etiology of Crohn's disease (CD) has drawn heated controversy in the literature. Compelling evidence in the literature has accumulated lately that could incriminate the Mycobacterium avium subspecies paratuberculosis (MAP), the well-known agent of John's disease in cattle. The evidence is isolation of the organism or its DNA and RNA, detection of the anti-MAP antibodies in Crohn's patients, increasing incidents of CD in areas close to the cattle pastures, and the possibility of treating the disease with the antibiotics. The group that favors the immune dysregulation theory considered this evidence circumstantial due to the variations in these reports. The treatment of CD with humanized anti-tumor necrosis factor-alpha antibodies is considered great endorsement to the immune dysregulation theory. The endless debate could jeopardize public health rather than bring a final solution. Reconciliation between the 2 theories appears inevitable in view of possible classification of this disease as a zoonotic.

Diazinon immunotoxicity in mice: modulation of cytokines level and their gene expression.

Diazinon is one of the organophosphate pesticides of wide spectrum insect-killing power. Diazinon extensive application as an effective pesticide was associated with direct or indirect modulation of major and vital immune mechanisms. This study addressed the effect of diazinon toxicity on cytokines that are involved in the regulation of innate, cellular and humoral immune responses. Mice intoxicated with 50 mg/kg (1/5 LD50) body weight for 30 days indicated gradual decrease in the level of interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-10 (IL-10), interleukin-12 (IL-12) and interferon-gamma (IFN-gamma) in the splenocytes cultures that were pulsed with phytohaemagglutinin (PHA). Sever suppression of these cytokines was confirmed by the RT-PCR. The level of IL-10 in CD4(+), CD8(+), and B cells indicated significant increase, whereas INF-gamma level was significantly decreased in B cells only. On the molecular level, the INF-gamma mRNA synthesis was significantly increased in all cells subpopulation, whereas, IL-2 mRNA synthesis was only increased in CD4(+). It was shown that diazinon immunotoxicity in mice capable of modulating the major cytokines involved in the regulation of the immune responses. In certain stage of diazinon toxicity, Th2 type responses appeared dominant. Diazinon could accelerate the INF- gamma and IL-2 mRNA synthesis but their translation might be impaired.

The cytokines of bovine mammary gland: prospects for diagnosis and therapy.

The lack of efficacy of conventional strategies for the maintenance of healthy udders in domestic cattle has prompted studies on the use of cytokines for this purpose. The adjuvant use of recombinant bovine cytokines, such as IL-2, IFN-gamma and TNF-alpha, in normal mammary gland, mobilizes innate and acquired immunity. However, stimulated immunity does not prevent or eradicate infection, particularly in the case of Staphylococcus aureus mastitis. Cytokines do, however, improve the bactericidal efficiency of certain antibiotics. The subtle and sensitive changes in the cytokine network of normal and mastitic bovine mammary gland may encourage the use of cytokines in the diagnosis and prognosis of udder health. Numerous studies support this hypothesis, and detection and monitoring of cytokines could become an important alternative management for udder health. The use of cytokines in the immunotherapy, diagnosis and prognosis of mastitis will grow with knowledge of the cytokine network in bovine mammary glands and the development of efficient cytokine diagnostic techniques.