Sheep Pox Research Articles

Cultivation of sheep pox virus on the chorioallantoic membrane of chicken embryo

Cultivation of sheep pox virus on the chorioallantoic membrane of chicken embryo

Morphology and physical characteristics of sheep and goat pox viruses

Morphology and physical characteristics of sheep and goat pox viruses

Characteristics of a virus causing a pox disease in sheep and goats in Kenya, with observations on the epidemiology and control

The sheep and goat pox viruses isolated in Kenya are not host specific as in the Middle East and India. The virus strains from one species are of a similar pathogenicity for the other, and the same virus appears to occur in the field outbreaks in mixed flocks. A silent infection with no skin lesions occurs in the field outbreaks. The virus grows well in lamb testis cell cultures, it does not haemadsorb nor haemagglutinate and is ether sensitive. Most strains could not readily be adapted to grow on the chorioallantoic membrane of embryonated eggs; one isolation only was made in this way. Staining of the virus inclusions showed that they were of DNA; the virus resembled that of lumpy skin disease in many characteristics. It was possible to cross-protect both species with virus of sheep or goat origin. A vaccine was made from tissue culture virus adsorped onto aluminium hydroxide gel and treated with formalin.

Observations on the use of live-modified tissue culture vaccine against Sheep Pox

Observations on the use of live-modified tissue culture vaccine against Sheep Pox

Experimental Sheep Pox A Histological and Ultrastructural Study

Sheep pox virus infection of the skin of susceptible sheep induced marked hyperplasia of the epithelium and proliferation of endothelial cells lining small blood vessels. When infectivity of the lesion was greatest the blood vessels developed a severe necrotising vasculitis and thrombosis with resultant necrosis of the dermis. Cells appeared in the dermis with a very characteristic morphology, the so-called ‘sheep pox’ cells or ‘cellules claveleuses’ of Borrel. These cells had a vacuolated nucleus and usually a large intracytoplasmic inclusion body. They appeared to represent a range of cell types including monocytes, macrophages and fibroblasts. The intracytoplasmic inclusion bodies were sites of sheep pox virus replication.

Tests in Sheep of Attenuated Sheep Pox Vaccines

Summary Sheep pox virus (SPV) attenuated by continuous passage in either lamb kidney (LK) or calf kidney (CK) cells was tested for immunizing properties in sheep. A mixture of the 491th and 50th LK passage of the virus, although partially attenuated, was too virulent for general use as a vaccine. By passage 72 the virus was well attenuated but gave variable protection to sheep challenged by infection with virulent virus. SPV passaged 37 times in CK cells, proved to be of low virulence, immunized sheep for at least 23 weeks, and contained at least one 50% protective dose in 0·5 ml of a 10−5.2 dilution. A duration of immunity experiment showed that Borrel-type aluminium hydroxide adsorbed vaccine gave a low level of protection which was lost before 8·5 months. In contrast the CK passaged virus protected more sheep for a longer period. The best vaccine tested was CAT 32 which produced in about 61% of sheep small subcutaneous nodules following vaccination. The immunity conferred by this vaccine protected sheep against challenge for at least 1 year.

Factors Associated with the Production of Attenuated Sheep Pox Vaccines

The production of substantial volumes of attenuated virus on calf kidney cell monolayers is described. In order to conserve stocks of seed virus it was necessary to inoculate bottles with low concentrations. With input multiplicities of less than about 0·002, virus production was reduced because of early detachment of the cell monolayers. Progress of viral destruction of the cells was always slow, particularly in monolayers prepared from kidney cells derived from calves several weeks old. In the system used virus was first released from infected cells after 51/1 and 110 improvement in yield was obtained by infecting incomplete monolayers. Release of virus from cells was obtained most readily by freezing and thawing once. Loss of infectivity during lyophilization was reduced by the addition of peptone, or lactalbumin hydrolysate or a mixture of the latter with sucrose. Lyophilized virus lost little or no infectivity when held at –20°C for 1 year. For use the lyophilized vaccine should be reconstituted and diluted 1/200 in distilled water. The half life of the virus suspension was found to be 31 days at +4°C.

Characteristics of a paravaccinia virus from cattle.

A strain of paravaccinia virus (66/1456Sc) was isolated from nasal flushings and pharyngeal swabbings collected from one calf involved in an outbreak of a respiratory disease syndrome which occurred in a group of 20 stabled cattle. The isolate appeared to be a lipovirus of the DNA type, pH 3 labile, heat sensitive, and not affected by either 2-(alpha-hydroxybenzyl)-benzimidazole in a concentration of 50 μg per ml or by a 0.125% solution of trypsin. The isolate multiplies in bovine embryo kidney (BEK) cell cultures, producing CPE characterized by the formation of “closed plaques” and intracytoplasmic inclusions. It possesses morphologic characteristics peculiar to those of the paravaccinia viruses, and dimensions of approximately 280 by 160 mμ. The virus is devoid of hemagglutination or hemadsorption activity, and failed to infect sheep, rabbits, or mice, or to produce lesions on the CAM of fertile hens' eggs. Cattle inoculated intranasally, intravenously, or intramuscularly with the isolate, or by the intradermal route in the neck or muzzle, remained clinically healthy. However, when inoculated into the submucosa of calves, or intradermally into the teats of milking cows, the virus produced small ulcerative lesions in the former and erythematous nodules in the latter animals. Neutralizing antibodies were not produced by any of the animals injected with the agent, except by rabbits in one of three attempts. The virus under study was partially neutralized by antiserum to a strain of pseudo-cowpox virus, but no serologic crossing occurred between the isolate and antiserums to any of the following viruses: parainfluenza-3, vaccinia, bovine viral diarrhea, infectious bovine rhinotracheitis, pseudorabies, Shope fibroma, or sheep pox. The isolate reactivated heat-inactivated Lancy-Vaxina strain of vaccinia virus in CAM and BEK cell cultures. Studies of the isolate in cattle indicate that it was not responsible for the respiratory signs observed in the disease outbreak from which it was isolated.

Studies on the serological relationships between avian pox, sheep pox, goat pox and vaccinia viruses.

By using neutralization, complement fixation and immunogel-diffusion tests, it has been demonstrated that cross-reactions occur between various avian pox viruses and between sheep pox and goat pox viruses. No such reactions were demonstrated between avian pox viruses and vaccinia virus or between avian pox and sheep pox and goat pox viruses. Furthermore, no serological relationship was demonstrable between vaccinia virus and sheep pox and goat pox viruses.

Clinical and Histopathological Study of Sheep Pox in Ethiopia

Clinical signs, postmortem and histopathological lesions in sheep suffering from sheep pox were evaluated. Animals were selected purposively from Yemeze Gera Midir, Kalu and Kutaber district veterinary clinics, Ethiopia. Relevant data and samples were collected for the period from November, 2007 to December, 2009. Of the total 3263 sheep examined, 49.5% (1615) showed skin lesions, suppressed appetite and depression. The lesions were detected in all ages and both sexes. The chief clinical signs observed were: fever, macules, papules, nodules, enlarged lymph nodes, dyspnea, conjunctivitis, nasal discharge and labored and noisy breathing. The mortality rate was 10.42% (340). At postmortem, the skin showed necrotic lesions and scabs surrounded by areas of edema, hemorrhage and congestion. The mucous membranes of the eyes, nose, mouth, vulva and prepuce were ulcerated. The lungs contained edematous, congested, consolidated areas, and firm gray to white nodules. Papules and ulcerated areas were common on the abomasal mucosa. The histopathologic examination of hematoxylin and eosin and van Gieson stained skin biopsy sections taken from 21 sheep were done in Sebeta National Veterinary Diagnostic Center. The degree of damage on the skin varied from minimal to severe. The reaction to the virus range from few epidermal hyperplasia to different degrees of degeneration and necrosis of epidermis and dermis. DOI: http://dx.doi.org/10.3329/ijns.v1i4.9734 IJNS 2011 1(4): 89-92

A new approach to active immunization of sheep by a combined sheep pox and anthrax vaccine.

SummaryA combined vaccine against sheep pox and anthrax has been developed and used with good results in Iran in 3 million sheep of varying susceptibility.Untreated sheep having contact with immunized ones did not show any signs of disease.The combined vaccine is of potential economic importance since a single injection confers solid immunity against two major diseases of sheep.Our experiments show that the combined sheep pox and anthrax vaccine confers the same level of immunity as single vaccines.ZusammenfassungEin neuer Versuch zur aktiven Immunisierung von Schafen mit einer kombinierten Schafpocken‐Milzbrand‐VakzineEs wurde eine neue Vakzine gegen Schafpocken und Milzbrand entwickelt, die an 3 Millionen Schafen unterschiedlicher Empfänglichkeit mit gutem Ergebnis in Iran erprobt wurde.Ungeimpfte Schafe, die in Kontakt mit immunisierten standen, zeigten keinerlei Krankheitserscheinungen.Die kombinierte Vakzine hat eine große wirtschaftliche Bedeutung. Eine einzige Injektion vermittelt eine solide Immunität gegen zwei wichtige Schafseuchen.Aus den Versuchsergebnissen kann geschlossen werden daß die kombinierte Schafpocken‐Milzbrand‐Vakzine die gleiche Immunität gewährleistet die durch getrennte Impfungen mit monovalenten Impstoffen erzielt wird.RésuméUn nouvel essai d'immunisation active des moutons à l'aide d'un vaccin combiné contre la variole ovine et le charbon bactéridienOn met au point un nouveau vaccin contre la variole ovine et le charbon bactéridien qui a été testé sur 3 millions de moutons de réceptivité variable et donné de bons résultats.Les moutons non vaccinés, qui se trouvaient en contact avec les animaux immunisés, ne manifestèrent aucun signe de maladie.Le vaccin combiné a une grande importance économique. Une seule injection confère une solide immunité contre deux maladies épizootiques sérieuses du mouton.On peut déduire des résultats de l'expérience, que le vaccin combiné contre la variole ovine et le charbon garantit une immunité identique à celle que l'on obtient à l'aide de vaccinations séparées avec des vaccins monovalents.ResumenUn ensayo nuevo para la inmunización activa de las ovejas con una vacuna combinada frente a la viruela ovina y el carbunco bacteridianoSe desarrolló una vacuna nueva frente a la viruela ovina y el carbunco bacteridiano, que se probó con éxito satisfactorio en 3 millones de ovejas de receptividad diversa.Las ovejas no vacunadas, que se hallaban en contacto con las inmunizadas, no mostraron síntomas nosológicos de ninguna clase.La vacuna combinada tiene una importancia económica grande. Una sola inyección proporciona una inmunidad sólida frente a dos enfermedades infectocontagiosas importantes para las ovejas.De los resultados ecperimentales se puede deducir que la vacuna combinada contra la viruela ovina y el carbunco bacteridiano garantiza la misma inmunidad que se logra mediante inoculaciones por separado con vacunas monovalentes.

An autoradiographic and immunofluorescent study of the infectious cycle of sheeppox virus in cell cultures exposed to 5-fluorodeoxyuridine.

No progeny virus is detected by determination of the infectivity titres when embryo muscle cell cultures are exposed to a concentration of 10−5 M of 5-fluorodeoxyuridine at the time of sheeppox virus infection. The autoradiographic preparations of FUdR treated cells showed cytoplasmic labelling into viral DNA (tritiated deoxyuridine) in 4 to 9% of the cells during the first 24 hours of infection. In cells exposed to FUdR in which viral DNA synthesis was detected by autoradiography, progeny virus not detectable by infectivity test might be produced. The demonstration of viral proteins by immunofluorescence served to establish that viral DNA synthesis is not essential for viral protein synthesis in FUdR treated cells. Under light microscopy, there is no apparent difference between the cytopathic effects of viral infection in treated and in untreated cells.

Development of an attenuated live virus vaccine against sheep pox.

SummaryLaboratory experiments and field investigations showed that the live modified sheep pox virus vaccine, strain RM/65, is completely innocuous after 30 consecutive passages in sheep kidney cells.Sheep vaccinated with a single dose of vaccine resist the challenge dose of virulent virus.The vaccine does not lose its immunizing power when kept for more than 2 months at room temperature and 20 days at 37° C.Vaccinated animals do not spread the disease.The attenuated virus is capable of stopping outbreaks in the field. Since the immunity is established within a short time after vaccination, the vaccination of apparently healthy animals in infected flocks prevents progress of an outbreak.ZusammenfassungEntwicklung einer abgeschwächten Lebendvirus‐Vaccine gegen SchafpockenLaboratoriums‐ und Feldversuche zeigten, daß die aus dem Schafpocken‐Virus, Stamm RM/65, hergestellte modifizierte Lebendvakzine nach 30 aufeinanderfolgenden Passagen auf Schafnierenzellen völlig unschädlich ist. Schafe, die mit nur einer einzigen Vakzinedosis behandelt wurden, widerstehen einer Belastung mit virulentem Virus.Auch nach mehr als zweimonatiger Aufbewahrung bei Zimmertemperatur und nach 20 Tagen bei 37° C verliert die Vakzine ihre Immunisierungskraft nicht. Vakzinierte Tiere verbreiten die Erkrankung nicht. Das abgeschwächte Virus ist imstande, in der Praxis Ausbrüche aufzuhalten. Da sich die Immunität innerhalb kurzer Zeit nach der Vakzinierung ausbildet, kann diese bei offensichtlich noch gesunden Tieren in infizierten Herden einem weiteren Umsichgreifen der Erkrankung vorbeugen.RésuméLe développement d'un virus vaccin atténué contre la claveléeDes éxperiences de laboratoire ainsi que des éssais sur le terrain, prouvent que le virus vaccin modifié, souche RM/65, est complètement inoffensif après 30 passages successifs sur les cellules rénales de mouton.Les moutons vaccinés avec une seule dose de ce vaccin résistent à l'épreuve à l'aide d'un virus virulent.Le vaccin ne perd pas son pouvoir antigénique après un stockage de 20 jours à 37° C ou de plus de 2 mois à la température du laboratoire.Les animaux vaccinés ne diffusent pas la maladie.Le virus atténué est capable de bloquer sur le terrain la propagation d'une infection naturelle. Comme l'immunité s'établit rapidement, la vaccination des moutons apparament sains dans un troupeau infecté permet l'éradication de l'épizootie.ResumenLogro de una virus‐vacuna viva atenuada frente a la viruela ovinaLos ensayos de laboratorio y campales evidenciaron que la vacuna viva modificada obtenida a partir del virus de la viruela ovina, cepa RM/65, es innocua por completo tras 30 pasajes sucesivos en células renales de oveja. Las ovejas tratadas con una sola dosis vacunal resisten un gravamen con virus virulento.Incluso tras su conservación durante más de dos meses a temperatura ambiente y tras 20 días a 37° C, la vacuna no pierde su poder inmunizante. Los animales vacunados no difunden la enfermedad. El virus atenuado es capaz de detener los brotes registrados en la práctica rural. Puesto que la inmunidad se forma dentro de un espacio breve de tiempo tras la vacunación, ésta puede prevenir el esparcimiento ulterior de la enfermedad en los animales todavía sanos en apariencia.

Autoradiographic Study on Sheeppox Virus Infection

Terrinha, António M. (National Laboratory for Veterinary Research, Lisbon, Portugal), José D. Vigário, José L. Nunes Petisca, J. Moura Nunes, and Armando L. Bastos. Autoradiographic study on sheeppox virus infection. J. Bacteriol. 90:1703-1709. 1965.-An autoradiographic study of sheep embryo cell cultures infected with sheeppox virus showed that viral deoxyribonucleic acid (DNA) synthesis starts at 10 to 11 hr after infection. The number of cells which supported viral DNA synthesis increased until 22 to 23 hr. The extent of cytoplasmic continuity between cells might permit the cell-to-cell transfer of mature virus or perhaps viral DNA. There is evidence of an inhibitory action on cellular DNA synthesis in cells which supported viral DNA synthesis, but, in all cellular populations infected, a small proportion of cells was encountered which supported viral DNA synthesis in compartment S. No evidence for cellular division of sheeppox virus-infected cells has been found. Enzymatic digestion by deoxyribonuclease combined with autoradiography provided an indirect demonstration of the time at which the first viral structural proteins were found to be synthesized, that is, 18 hr after infection. A progressive increase in synthesis of viral structural proteins was demonstrated. Virus maturation occurred within the cells in the cytoplasm, predominantly in the same sites as viral DNA synthesis.

Lumpy Skin Disease—The Determination of the Immune State of Cattle by an Intradermal Test

An intradermal test for demonstrating the immune state of cattle to lumpy skin disease (LSD) is described. The methods of antigen preparation and interpretation of the reaction are given. Forty cattle immune to LSD were subjected to the test. Immune reactions were given by 77.5 per cent, doubtful reactions by 12-5 per cent and negative reactions by 10 per cent of the cattle. Fifty-eight cattle of unknown immune state were tested and subsequently challenged with LSD virus. Eighty-eight per cent of the animals reacting to the test were immune, 90.6 per cent of the animals negative to the test were susceptible to challenge. A sheep pox antigen was as efficient as LSD antigen in the determination of susceptibility to challenge. The value of the test in detecting susceptible animals for vaccine safety tests and for experimental work is discussed.

Protection of Cattle Against Lumpy Skin Disease: II—Factors Affecting Small Scale Production of a Tissue Culture Propagated Virus Vaccine

SUMMARY A method is described for the propagation of sheep pox virus in tissue culture of prepubertal lamb testes for use as an immunizing agent against lumpy skin disease. The virus titre obtained was apparently unaffected if cultures were used between the 3rd and 8th day after preparation. Maximum infective titres were achieved by 48 hours when inocula of high titre were used and by 8 days with inocula of low titre. Freezing and thawing of whole cultures gave satisfactory release of virus associated with cells. No loss of infectivity was demonstrated after freeze-drying and the freeze-dried vaccine was stable for long periods when stored in the dark at 4°C. and minus 20°C. When freeze-dried vaccine in either the dry or reconstituted state was stored in clear glass containers and exposed to sunlight, there was a loss of infectivity. No loss occurred when reconstituted vaccine was exposed to sunlight in amber glass containers.

Protection of Cattle Against Lumpy Skin Disease: I.—Trials with a Vaccine Against Neethling Type Infection

SUMMARY It is shown that 3 strains of sheep pox will protect cattle against experimental lumpy skin disease infection. The reasons for the choice of the “Kedong” strain of sheep pox as a vaccinating agent are given. The 50 per cent protective dose (PD50) for cattle was found to consist of eight point nine 50 per cent infective doses for tissue culture (TCID50). The size of the field dose of vaccine chosen was approximately 9,000 PD50 per animal. Safety trials of vaccine produced from a stock pool of virus are described. No spread of virus from cattle to sheep was demonstrated and alternate cattle/sheep passage was unsuccessful. In approximately 1,000 cattle no severe local reactions occurred. The vaccine was issued for experimental field use in 1959 and over 111,000 doses were used. The precautions to be taken during field use and the results of a survey of 57 vaccinated farms are detailed. Local reactions were observed in 0.3 per cent of the vaccinated cattle. On 10 farms vaccinated cattle were herded with sheep but there was no outbreak of sheep pox on the vaccinated farms. The use of sheep pox virus as a vaccinating agent against lumpy skin disease in cattle is discussed.

آبله بزی در ایران. پاساژهای سریال در بزها و تخم مرغهای جنین دار و ارتباط آن با آبله گوسفندی

آبله بزی در ایران. پاساژهای سریال در بزها و تخم مرغهای جنین دار و ارتباط آن با آبله گوسفندی

Goat Pox In Iran: Serial Passage in Goats and the Developing Egg, and Relationship with Sheep Pox

Goat Pox In Iran: Serial Passage in Goats and the Developing Egg, and Relationship with Sheep Pox

The Pathogenesis of Sheep Pox in the Skin of Sheep

The Pathogenesis of Sheep Pox in the Skin of Sheep