Between 1973 and 1975, 21 outbreaks of ASF were confirmed in the endemic area of the northern Transvaal after an interval of 10 years in which the disease was silent. The new series of outbreaks coincided with the isolation, for the first time in South-Africa, of two HAd- strains of ASF virus. The first of these virus isolates, Lillie-148, was obtained from swine which, judging from circumstantial evidence, had been infected by a warthog carrier of virus. The pigs on the farm were affected by a form of disease with a lower pathogenicity than that observed in previous epidemics. The second HAd- strain 24823 was obtained from a case from which neither clinical nor pathological observations were available. From the results of the biological tests carried out at the laboratory, however, it was deduced that the disease in the field may have had a chronic course. When the carrier status of populations of the argasid tick Ornithodoros moubata collected from warthog burrows was investigated, it was found that the situation in South Africa is analogous to that in East Africa. Twenty five per cent of burrows were found to be infected; the mean infective titres of the tick suspensions varied between 104,5 and 105,2 BCHAd50 and the mean percentage of infected argasids varied between 1,62 and 3,45. Infected ticks were also found in the Marico district, which is adjacent to the endemic area, but ASF has never been recorded there. From tick suspension TS237, showing both delayed and reduced haemadsorbing effect in huffy coat cell cultures, a HAd population of ASF virus was segregated. From these observations it was inferred that ASF virus may mutate from the HAd+ to the HAd- form in the primary virus reservoir. Furthermore, the virus appears to be evolving towards less pathogenic forms irrespective of prior adaptation of the infectious agent to domestic stock under the epidemiological conditions prevailing in South Africa. During this investigation it was found that LLC-MK2 cell cultures were susceptible to ASF virus. Cytopathic effects were observed in primary isolation and peak infectivity coincided with complete destruction of the cell monolayers, attained after three to four serial passages. The sensitivity of LLC-MK2 cells for estimating the virus content of porcine tissues was in two instances comparable to that of huffy coat cells, but in another three cases it was 100 to 1000 times lower. It was concluded that LLC-MK2 cells were a suitable complement to huffy coat cultures for the cultivation of ASF virus, particularly for HAd- isolates. After 35 to 45 serial passages in LLC-MK2 cells the HAd+ strains of ASF virus lost their haemadsorbing characteristics. A similar mutation, but more gradual, was also observed in huffy coat cell cultures. The feasibility of plaque production was studied in LLC-MK2 cell monolayers. Plaques were obtained with all the strains studied, irrespective of their adaptation to LLC-MK2 or buffy coat cells when 0,4% Agarose was used as a solidifying agent. The diameter of plaques ranged from 0,3 to 3,0 mm and this characteristic was unrelated to the haemadsorbing properties of the strains used. Plaque technique was successfully used to detect the presence of HAd- virus particles in HAd+ populations by subculturing selected virus-plaques into buffy coat cultures. The results of biological tests suggested that HAd strains have a reduced virulence which can vary within broad limits. The experience with strain Lillie-148 and 24823 showed that either acute or chronic or subclinical disease can follow infection of pigs with these isolates of virus. The results obtained with the two virus populations of strain TS237 emphasized the different degree of patho-genicity between HAd+ and HAd- virus. While the former was responsible for a peracute or acute form of disease, the latter produced chronic or subclinical infections. In pigs mild forms of ASF also developed following the inoculation of HAd+ strains obtained after serial passages in cell cultures. It was concluded that haemadsorption and pathogenicity are two characteristics that are not linked and can be modified independantly. AFRIKAANS : Gedurende die tydperk 1973-1975 het Afrikaansevarkpes (AVP), na 'n afwesigheid van 10 jaar, weer sy verskyning gemaak in die endemiese gebied van Noord Transvaal en altesaam 21 bevestigde geval1e is aangemeld. Die nuwe reeks uitbrake het sa.amgeval met die eerste isolasie in Suid-Afrika van twee HAd- stamme van AVP. Die eerste virusstam wat geisoleer is, was Lillie-148. Hierdie virusstam is geisoleer van 'n vark wat volgens omstandigheidsgetuienis deur 'n v1akvark besmet is. Die virus waarmee die varke op die plaas besmet is, het 'n laer patogenisiteit gehad as virusse van vorige uitbrake. Die tweede HAd- stam nl. 24823 is verkry van 'n geval waar geen kliniese of patologiese waarnemings beskikbaar was nieo Uit die resultate van laboratoriurntoetse is die gevolgtrekking gemaak dat die siekte wel moont1ik 'n kroniese verloop kon gehad het. Uit ondersoeke na die vektorstatus van populasies van die sagte bosluis Ornithodoros moubata, wat verkry is uit vlakvarkgate, is gevind dat die situasie in Suid-Afrika soortgelyk is aan die in Oos-Afrika. Daar is bevind dat 25 persent vlakvarkgate besmet is; dat die gemiddelde virus konsentrasies van bosluissuspensies varieer tussen 104,5 en 105,2 BCHAd50 en dat die gemiddelde persentasie van besmette bos1uise wissel tussen 1,62 en 3,45. Besmette bosluise is ook aangetref in die Marico-distrik wat aangrensend is aan die ensoötiese gebied en waar AVP nog nooit voorgekom het nie. 'n HAd- populasie van AVP virus is geisoleer van 'n bosluissuspensie, TS237, wat in wit selkulture 'n vertraagde en verminderde heem-adsorberende effek getoon het. Uit hierdie waarnemings is die gevolgtrekking gemaak dat AVP virus in die aanvanklike virus reservoir instaat is om van HAd+ na HAd- te muteer. Hieruit blyk dit dat onder die huidige epidemiese toestande, wat tans in Suid-Afrika heers, die virus skynbaar verander na 'n vorm van laer patogenisiteit. Dit geskied ongeag vroeëre aanpassing van die infektiewe agens by die plaaslike varkpopulasie onder heersende epidemiologiese toestande in Suid-Afrika. Gedurende hierdie ondersoek is dit aangetoon dat LLC-MK2 selkulture vatbaar is vir AVP virus. Primere virus isolasies toon sitopatogeniese effekte. Infektiwiteit bereik 'n piek na drie tot vier agtereenvolgende oorspuitings met algehele vernietiging van sellae. Die gevoelligheid van LLC-MK2 selle vir die bepaling van die virus inhoud van varkweefsel was in twee gevalle vergelykbaar met die van wit selle. In drie ander gevalle was dit 100 tot 1000 keer laer. Die gevolgtrekking is gemaak dat LLC-MK2 selle 'n geskikte aanvulling is vir wit selkulture vir die kweek van AVP virus, veral vir HAd- isolate. Die heem-adsorberende eienskappe van die HAd+ stam van AVP virus het verlore gegaan na 35 - 45 agtereenvolgende oorspuitings in LLC-MK2 selle. In wit selkulture is 'n soortgelyke mutasie waargeneem, hoewel dit meer geleidelik plaasgevind het. Die moontlikheid van plaket vorming in LLC-MK2 sellae is ondersoek. Wanneer 0,4% agarose as stollingsagens gebruik is, het alle stamme wat ondersoek is plakette opgelewer ongeag of hulle aangepas was vir LLC-MK2 selle of wit selle. Plakette se deursnee het gewissel tussen 0,3 en 3,0 mm. Hierdie eienskap is egter nie gekorreleerd met die betrokke stamme se heem-adsorberende eienskappe nie. Die teenwoordigheid van HAd- virus partikels in HAd+ populasies is aangetoon deur subkulture van geselekteerde plakette in wit selkulture te maak. Uit die resultate van biologiese toetse is die gevolgtrekking gemaak dat die HAd- stamme 'n verlaagde virulensie het wat kan wissel tussen wye grense. Die ondervinding met stam Lillie-148 en stam 24823 het aangetoon dat varke wat met hierdie virus stamme besmet raak akute, kroniese of subkliniese siekte toestande ontwikkel. Die graad van verskil tussen die patogenisiteit tussen HAd+ en HAd- virus is beklemtoon deur die resultate wat verkry is met die twee virus populasies van starn TS237. Die HAd+ stam veroorsaak perakute of akute vorms van die siekte terwyl HAd- starn kroniese of subkliniese infeksie tot gevolg het. Matige vorme van AVP is ook verkry nadat varke geinokuleer is met 'n HAd<sup+ starn wat 'n aantal oorspuitings in selkulture ondergaan het. Die afleiding is gemaak dat heem- adsorpsie en patogenisiteit twee eienskappe is wat nie verbonde is nie en dus onafhanklik van mekaar gemodifiseer kan word. Copyright / Gedurende die tydperk 1973-1975 het Afrikaansevarkpes (AVP), na 'n afwesigheid van 10 jaar, weer sy verskyning gemaak in die endemiese gebied van Noord Transvaal en altesaam 21 bevestigde geval1e is aangemeld. Die nuwe reeks uitbrake het sa.amgeval met die eerste isolasie in Suid-Afrika van twee HAd- stamme van AVP. Die eerste virusstam wat geisoleer is, was Lillie-148. Hierdie virusstam is geisoleer van 'n vark wat volgens omstandigheidsgetuienis deur 'n v1akvark besmet is. Die virus waarmee die varke op die plaas besmet is, het 'n laer patogenisiteit gehad as virusse van vorige uitbrake. Die tweede HAd- stam nl. 24823 is verkry van 'n geval waar geen kliniese of patologiese waarnemings beskikbaar was nieo Uit die resultate van laboratoriurntoetse is die gevolgtrekking gemaak dat die siekte wel moont1ik 'n kroniese verloop kon gehad het. Uit ondersoeke na die vektorstatus van populasies van die sagte bosluis Ornithodoros moubata, wat verkry is uit vlakvarkgate, is gevind dat die situasie in Suid-Afrika soortgelyk is aan die in Oos-Afrika. Daar is bevind dat 25 persent vlakvarkgate besmet is; dat die gemiddelde virus konsentrasies van bosluissuspensies varieer tussen 104,5 en 105,2 BCHAd50 en dat die gemiddelde persentasie van besmette bos1uise wissel tussen 1,62 en 3,45. Besmette bosluise is ook aangetref in die Marico-distrik wat aangrensend is aan die ensoötiese gebied en waar AVP nog nooit voorgekom het nie. 'n HAd- populasie van AVP virus is geisoleer van 'n bosluissuspensie, TS237, wat in wit selkulture 'n vertraagde en verminderde heem-adsorberende effek getoon het. Uit hierdie waarnemings is die gevolgtrekking gemaak dat AVP virus in die aanvanklike virus reservoir instaat is om van HAd+ na HAd- te muteer. Hieruit blyk dit dat onder die huidige epidemiese toestande, wat tans in Suid-Afrika heers, die virus skynbaar verander na 'n vorm van laer patogenisiteit. Dit geskied ongeag vroeëre aanpassing van die infektiewe agens by die plaaslike varkpopulasie onder heersende epidemiologiese toestande in Suid-Afrika. Gedurende hierdie ondersoek is dit aangetoon dat LLC-MK2 selkulture vatbaar is vir AVP virus. Primere virus isolasies toon sitopatogeniese effekte. Infektiwiteit bereik 'n piek na drie tot vier agtereenvolgende oorspuitings met algehele vernietiging van sellae. Die gevoelligheid van LLC-MK2 selle vir die bepaling van die virus inhoud van varkweefsel was in twee gevalle vergelykbaar met die van wit selle. In drie ander gevalle was dit 100 tot 1000 keer laer. Die gevolgtrekking is gemaak dat LLC-MK2 selle 'n geskikte aanvulling is vir wit selkulture vir die kweek van AVP virus, veral vir HAd- isolate. Die heem-adsorberende eienskappe van die HAd+ stam van AVP virus het verlore gegaan na 35 - 45 agtereenvolgende oorspuitings in LLC-MK2 selle. In wit selkulture is 'n soortgelyke mutasie waargeneem, hoewel dit meer geleidelik plaasgevind het. Die moontlikheid van plaket vorming in LLC-MK2 sellae is ondersoek. Wanneer 0,4% agarose as stollingsagens gebruik is, het alle stamme wat ondersoek is plakette opgelewer ongeag of hulle aangepas was vir LLC-MK2 selle of wit selle. Plakette se deursnee het gewissel tussen 0,3 en 3,0 mm. Hierdie eienskap is egter nie gekorreleerd met die betrokke stamme se heem-adsorberende eienskappe nie. Die teenwoordigheid van HAd- virus partikels in HAd+ populasies is aangetoon deur subkulture van geselekteerde plakette in wit selkulture te maak. Uit die resultate van biologiese toetse is die gevolgtrekking gemaak dat die HAd- stamme 'n verlaagde virulensie het wat kan wissel tussen wye grense. Die ondervinding met stam Lillie-148 en stam 24823 het aangetoon dat varke wat met hierdie virus stamme besmet raak akute, kroniese of subkliniese siekte toestande ontwikkel. Die graad van verskil tussen die patogenisiteit tussen HAd+ en HAd- virus is beklemtoon deur die resultate wat verkry is met die twee virus populasies van starn TS237. Die HAd+ stam veroorsaak perakute of akute vorms van die siekte terwyl HAd- starn kroniese of subkliniese infeksie tot gevolg het. Matige vorme van AVP is ook verkry nadat varke geinokuleer is met 'n HAd<sup+ starn wat 'n aantal oorspuitings in selkulture ondergaan het. Die afleiding is gemaak dat heem- adsorpsie en patogenisiteit twee eienskappe is wat nie verbonde is nie en dus onafhanklik van mekaar gemodifiseer kan word. Copyright / Thesis (DVSc)--University of Pretoria, 1977. / Companion Animal Clinical Studies / unrestricted

Šiuo tyrimo tikslas buvo ištirti laukinių ir naminių kiaulių halotano geną. Tyrimo metodika. Tyrimas atliktas 2012-2013 m. LSMU Biologinių sistemų ir genetinių tyrimų institute K. Janušausko gyvūnų genetikos laboratorijoje. Viso, HAL geno atžvilgiu, ištirta 137 kiaulė (45 šernai, 5 Vietnamietiškos kiaulės, 12 Pekariai, 25 Landrasai, 25 Jorkšyrai ir 25 Pjetrėnai). Kiaulių šeriai buvo naudojami kaip genetinės medžiagos šaltinis. Halotano geno nustatymui buvo atliekama polomerazės grandininės reakcija (PGR). HAL geno įtakai mėsinėms ir penėjimosi savybėms įvertinti buvo atrinkti mišrūnai LxJxP (45) auginti Valstybinėje kiaulių veislininkystės stotyje. Penėjimosi ir mėsinių savybių duomenys gauti iš Valstybinės kiaulių kontrolinio penėjimo stoties Kauno skyriaus. Rezultatai ir išvados. Iš 75 tirtų naminių kiaulių 88 proc. buvo NN ir 12 proc. Nn genotipo. Visos (62) laukinė kiaulės buvo NN genotipo. Aukščiausias n alelio dažnis nustatytas pas Pjetrėnų (p<0,01) veislės kiaules lyginant su Landrasais ir Joršyrais. Tuo tarpų N alelio didžiausias dažnis rastas pas Jorkšyrų veislės kiaules. Kadangi visos tirtos laukinės kiaulės neturėjo streso geno (n) alelio galima daryti prielaidą, jog jos yra atsparesnės stresui. Mūsų tyrimų duomenimis HAL geno homozigotinių ir heterozigotinių kiaulių mėsinių ir penėjimosi savybių rodikliai skiriasi. Šiltos skerdėnos masė, skerdenos puselės ilgis ir bekono puselės ilgis buvo didesni pas NN genotipo namines kiaules. Pas heterozygotinius individus... [toliau žr. visą tekstą] / The aim of present study was to research halothane gene in wild and domestic pigs. Research methodology. Research was performed during 2012 – 2013 year in LSMU Biological Systems and Genetic Research Institute of K. Janusauskas Animals Genetic Laboratory. Samples for DNA testing were collected from wild and domestic pigs. Fattening and meat quality data were obtained from the State of Pigs Control fattening Station of Kaunas Department. A total of 137 pigs (45 wild boars, 5 Vietnamese pigs, 12 Pecari, 25 Landrace, 25 Yorkshire and 25 Pietrian) were tested for halothane genotype. For the effect of HAL gene on meat and fattening properties, 45 crossbreeds (LxJxP) from State Pigs Breeding Station were selected. Plucked hair was used as a source of genomic DNA. All tested animals were characterized as normal homozygotes (NN), heterozygotes (Nn) or recessive homozygotes following amplification of a target region of the HAL gene using the polymerase chain reaction (PCR), followed by a restriction endonuclease assay. The resulting PCR was digested with the restriction enzyme Alw21I, followed by agarose gel electrophoresis. Results and conclusions. In 75 tested domestic pigs, 88 % were NN and 12 % were Nn genotype. In 62 tested wild pigs all animals were NN genotipe. The frequency of n allele was higher (p<0.01) in Petrian pigs (0.25 for n) than in Landrase (0.1 for n) and Yorkshire (0.05 for n). The frequency of N allele was higher in Yorkshire than in the rest of the tested... [to full text]

African Swine Fever Virus (ASFV) is an Asfivirus and is the only member of the family Asfarviridae. It manifests as a disease that varies from acute to sub-acute or chronic forms. A true carrier state in domestic pigs is unknown but chronically affected individuals may carry and spread the virus for extended periods. African Swine Fever (ASF) is a socio-economically important disease characterized by high morbidity and mortality affecting the livelihood of many small to big scale farmers and seriously compromising international trade. Strategic measures to control this disease are by physical containment and culling in outbreak situations. There is no vaccine available. Nevertheless, every pork producer should ideally be actively involved in having biosecurity measures in place to avoid contamination and contacting their veterinary services in case of suspicion of ASF to have appropriate samples analysed. Official veterinary services must be equipped with proper diagnostic tools in order to provide a quick response. The sensitivity of currently available diagnostic tests at the Transboundary Animal Diseases Programme, Onderstepoort Veterinary Institute was analysed in order to report the best technique available. Sensitivity to ASF virus infection and therefore diagnostic potential of cell primary cultures as bone marrow macrophages, blood macrophages and alveolar macrophages was done via comparison of titre results from inoculations of ASFV SPEC 257 as control, and ASFV MOZ 1/98. In addition, molecular detection of specific DNA fragments within the viral genome were compared using five different PCRs. Bone marrow macrophage cultures and blood macrophage cultures were the most reliable cells whereas alveolar macrophages more often showed contamination. Results show that PPA PCR and real time PCR detected the highest diluted samples, thus the lowest concentration of virus, in both trials done with ASFV MOZ 1/98 and ASFV SPEC 257. In addition, animal trials were performed by inoculating domestic pigs with four different ASFV isolates of varying pathogenicity. These viruses were all from distinct geographic origins. Non-virulent ASFV OURT 3/88 and high virulent ASFV BENIN 1/97 were previously described and used as reference viruses. ASFV MOZ 1/98, suspected of having high virulence and ASFV MKUZE, which was thought to be of low virulence were included in this study to provide further information on the pathological and clinical outcome of the disease as well as measuring viral replication in various organs and blood. The study showed that ASFV MKUZE was of intermediate virulence, whilst ASFV MOZ 1/98 was highly virulent with a high mortality rate. Results confirmed the inadequacy of ASFV MKUZE to act as vaccine opposed to ASFV OURT 3/88. Following this, a potential vaccine by use of attenuated Portuguese ASFV OURT 3/88 tested against virulent heterologous challenge with a strain now known with certainty to cause acute ASF, the isolate ASFV MOZ 1/98 collected from a diseased pig in Mozambique. Domestic commercial pigs where submitted to either one or two vaccinations before challenge. Viral load in blood and tissue samples was higher in unvaccinated animals and higher in single vaccinated than in pigs vaccinated twice. However, acute ASF afflicted all groups with severe clinical signs and post-mortem lesions. Although it did not confer total immunity it was determined that pigs vaccinated with European attenuated ASFV OURT 3/88 acquired partial protection against challenge with virulent southern Africa ASFV MOZ 1/98. / Dissertation (MSc)--University of Pretoria, 2012. / gm2014 / ab2015 / Veterinary Tropical Diseases / unrestricted