Studies on Rift Valley fever. Passive and active immunity in lambs

Smithburn (1949) reported that humoral immunity to Rift Valley fever (R.V.F.), transmitted from an immune ewe to her twin lambs, persisted for about five months and was not affected by weaning. He postulated that this might be of practical value in protecting young lambs during the period of maximum susceptibility to Rift Valley Fever virus. In the Republic of South Africa, arthropod-borne diseases of sheep such as Rift Valley fever, Wesselsbron disease and bluetongue occur seasonally during the late summer and autumn, and almost invariably disappear soon after the first frosts of winter. Bearing this in mind, practical use is made of transmitted passive immunity to protect the lambs. Autumn lambing is advocated, and farmers are advised to immunise all their sheep during the spring, first with a polyvalent bluetongue vaccine and later with a combined Rift Valley fever-Wesselsbron vaccine. On account of the abortifacient and embryotropic properties of the neuroadapted Rift Valley fever and Wesselsbron disease viruses which form the basis of the live attenuated virus vaccine, prophylactic immunisation is restricted to non-pregnant animals. At present, for the preparation of the Rift Valley fever vaccine, Smithburn's neurotropic attenuated strain of virus at the 102nd mouse intracerebral passage level is used. Mulligan (1937) prepared a similar type of vaccine from a neurotropic strain of virus at the 92nd mouse passage level. He reported that “the vaccine proved safe for lambs six weeks old and produced a good immunity. Tested in the field, on a large number of pregnant ewes and newly born lambs, this vaccine was found to be unsafe for the newly born lambs and to cause abortion in some of the pregnant ewes. Vaccination of pregnant ewes, moreover, did not appear to result in the transfer of the immune bodies through the colostrum to the lamb although, in this connection, it must be stated that lambing had started at the time vaccination was practised and the interval between inoculation and the birth of a lamb was never more than a few days. It became apparent, however, that the vaccine, while it might be of service in protecting maiden ewes, was not suitable for controlling an outbreak in pregnant ewes and very young lambs." Kaschula (1953) using Smithburn's neurotropic virus at the 86th passage level reported abortions among pregnant ewes and the death of lambs shortly after birth under field conditions in South Africa. The investigations reported in this communication were undertaken initially to determine the effect of the strain of Rift Valley fever virus incorporated in the vaccine on pregnant ewes and day-old lambs. During the course of the investigations valuable information was obtained on the nature and duration of transmitted immunity in lambs and the immune response of day-old lambs to the neurotropic strain of Rift Valley fever virus.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

The significance of reflex salivation in relation to froth formation and acute bloat in ruminants

(1) Frothing of ruminal ingesta is the main cause of bloat in sheep on green lucerne (2) It was found that the formation of froth is dependent on the consistency of the ruminal ingesta which in turn is influenced by reflex salivary secretion. (3) Reflex salivary secretion is largely stimulated by the presence of coarse material in the forestomachs and the amount of saliva secreted, therefore, depends on the physical condition of the feed. The explanation for the protective action of hay is based on this finding. (4) The condition and type of lucerne fed has a direct bearing on the occurrence of bloat.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Physiological studies on eructation in ruminants

(1) The eructation reflex in sheep and cattle, and factors affecting it, have been studied mainly by the method of forced air insufflation and direct recording of intraruminal pressure. (2) Eructation is a complex, co-ordinated reflex involving the rumen, reticulum, cardiac orifice and the oesophagus. It consists essentially in the movement of free gas from the dorsal rumen, forwards and downwards to the cardia. This is accomplished by- (a) A forward wave of contraction of the ruminal musculature (as distinct from the usual backward cycle of contractions). (b) Opening of the cardiac orifice which is brought about by contraction of the lateral and medial pillars of the rumino-reticular fold . (c) The clearing of the cardia of fluid ingesta is affected by relaxation of the reticulum. The relative importance of this phase depends on the degree of filling of the rumen. (3) The main stimulus for eructation is gas pressure in the posterior dorsal sac of the rumen. (4) From variations amongst the individual experimental animals it is believed that the efficiency of the reflex may depend on hereditary factors. (5) The factors affecting the reflex are: - A. Mechanical. (i) Obstruction of the oesophagus. (ii) Frothing of the ingesta. (iii) The degree of filling of the rumen and posture. Overfilling of the rumen was found to hinder eructation by increasing the distance between the free gas and cardiac orifice. Elevation of the hindquarters had a similar effect, while elevation of the forequarters mitigated the effects of overfilling. Animals with a non-functioning reticulum were found to be particularly susceptible to overfilling. B. Alkalosis. In the absence of other factors, the efficiency of eructation was found to vary inversely with the degree of alkalosis as determined by the CO₂-combining power of the blood. This was due mainly to reticular paralysis. C. Abdominal Vagotomy. Section of the right ventral branch of the vagus caused abomasal distension and chronic tympany, again due mainly to inhibition of reticular activity. Section of the left dorsal branch diminished the strength of ruminal contractions and eructation efficiency for the first three weeks with subsequent partial recovery. D. Reflex inhibition from the Posterior Digestive Tract. Distension of both the abomasum and caecum reduced the eructation efficiency again by inhibition of the reticulum. E. The effect of Drugs influencing Ruminal Motility. (i) Hypomotility. (a) Small doses of prussic acid inhibited the reticulum and backward movement of the rumen with consequent inefficiency of eructation and abolition of the reflex. (b) Atropine, histamine and adrenaline were found to inhibit the reflex completely even before a total paralysis of the rumen was induced. (ii) Hypermotility. Carbamylcholine and veratrine both cause spasm of the rumen and reticulum with consequent interference with eructation. Their therapeutic use is contraindicated.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

A re-assessesment of the shallow paleomagnetic inclinations of the Western Cyclades, Greece

Στις Μεσο-Μειοκαινικές λιμναίες αποθέσεις και τα δακιτικά ηφαιστειακά πετρώματα της λεκάνης Κύμης-Αλιβερίου έχουν παρατηρηθεί σταθερά μικρές εγκλίσεις σε παλαιομαγνητικές μετρήσεις οι οποίες έχουν αναφερθεί ως αποδεικτικό στοιχείο είτε για τοπική γεωμαγνητική ανωμαλία είτε για μετατόπιση προς βορρά της περιοχής του Αιγαίου. Παρουσιάζονται νέα δεδομένα μετρήσεων παλαιομαγνητισμού σε λιμναία στρώματα τα οποία δεν παρουσιάζουν μικρές εγκλίσεις και είναι συμβατά με απόθεση κοντά στο σημερινό γεωγραφικό πλάτος τους. Οι ιδιαίτερα μικρές εγκλίσεις και αποκλίσεις προς τα ανατολικά που έχουν αναφερθεί στις ηφαιστειακές διεισδύσεις του Οξύλιθου είναι αποτελέσματα ακατάλληλης διόρθωσης ως προς οριζόντιο άξονα. Οι υπερβολικά μικρές παλαιομαγνητικές εγκλίσεις που έχουν αναφερθεί στα πλουτώνια σώματα της Μυκόνου και τη Νάξου, Μέσο-Μειοκαινικής ηλικίας παραμόρφωσης, είναι συμβατές με επαναπροσανατολισμό μιας αρχικής θερμο-παραμένουσας μαγνήτισης που προέκυψε κατά την ψύξη τους κάτω από 580°C την οποία ακολούθησε ιξωδοελαστική παραμόρφωση σε θερμοκρασίες 400-500°C. Δευτερεύουσες μαγνητίσεις που παρατηρήθηκαν στα πετρώματα αυτά αντικατοπτρίζουν, πιθανότατα, τη διαδικασία μίας σταθερής -χημικής προέλευσης- παραμένουσας μαγνήτισης, παράλληλα με την προϋπάρχουσα μαγνήτιση υψηλής θερμοκρασίας, ως αποτέλεσμα της δημιουργίας μαγκεμίτη σε χαμηλή θερμοκρασία (<350°C). Κατά συνέπεια δεν μπορούμε να βρούμε ικανοποιητικές αποδείξεις είτε για τοπική μαγνητική ανωμαλία ή μετακίνηση του Αιγαίου προς βορρά είτε για περιστροφή των μικρής κλίσης κανονικών ρηγμάτων που συνθέτουν το σύστημα αποκόλλησης των Βορείων Κυκλάδων.Consistently shallow paleomagnetic inclinations measured in Early to Middle Miocene lacustrine and dacitic volcanic rocks of the Kymi-Aliveri basin have been cited as evidence for an anomalous geomagnetic field geometry or northward drift of the Aegean Sea region. We present new paleomagnetic data from the lacustrine beds that are instead not anomalously shallow and consistent with deposition near their present-day latitude as predicted by global apparent polar wander paths. Anomalously shallow inclinations and easterly declinations reported from the Oxylithos volcanics are an artifact of an inappropriate tilt correction. The excessively shallow paleomagnetic inclinations reported from the deformed Middle Miocene plutons on Mykonos and Naxos are consistent with reorientation of an original thermoremanent magnetization acquired during cooling below 580°C by subsequent ductile strain at temperatures of 400-500°C. Magnetization overprints observed in these rocks may reflect the acquisition of a stable chemical remanent magnetization lying parallel to the transposed high-temperature magnetization as the result of low-temperature (<350°C) maghemitization. We therefore find no convincing evidence for an anomalous Middle Miocene field geometry, northward drift of the Aegean, or back-tilting of the low-angle normal faults that constitute the North Cycladic Detachment System

Studies on the comparative actions of carbamylcholine, physostigmine and neostigmine in different species of domestic animals

In a series of experiments the comparative actions of carbamylcholine, physostigmine and neostigmine were compared in different species. Carbamylcholine was shown to have the following undesirable effects: (i) Respiratory distress due to bronchial secretion and constriction. (ii) Marked drop in blood pressure due to vasocollapse. (iii) Production of uncoordinated contractions of the rumen and inhibition of the reticulum. (iv) Profuse salivation. . (v) Little effect on the large intestine of the horse or sheep. It was more active on the stomach and bladder than the other two drugs tested. Physostigmine and neostigmine had very similar actions characterised by: (i) A slight rise in blood pressure after therapeutic doses. Evidence is produced indicating that this may be due to adrenaline secretion. (ii) Very little effect on the heart rate, salivary secretion or bronchioles. (iii) Little effect on the stomach of the dog or donkey. Increased strength of the contractions of the rumen and reticulum. Marked stimulation of the large intestine in all species. The impression was gained that neostigmine produced purgation in equines and dogs with less signs of colic than did physostigmine.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Sedimentation of bacteria with polyethylene glycol

Experiments are reported which show that the addition of 4,0% polyethylene glycol (6 000 MW) to liquid cultures of Clostridium welchii Type D , Pasteurella and Vibrio fetus (venerialis) will effectively sediment the bacteria. Live Brucella abortus S19, a smooth S. gallinarum Strain 28 600 and a formalin inactiviated suspension of V. fetus (intestinalis) Strain 661 were, however, not sedimented. When effective the method has appreciable application in the production of vaccines and other processes requiring the easy collection of large volumes of cells, and the separation of bacteria from their soluble exotoxins.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Aureomycin in the treatment of heartwater

1. The value of aureomycin in the treatment of heartwater has been established. It is considerably more effective than the sulphonamides. 2. The minimal therapeutic dose for sheep appears to be 2•5 mg. per lb. administered intravenously either as a single dose or in divided doses at intervals of 24 hours. 3. Doses smaller than the curative dose have a marked effect upon the course of the disease. 4. In cattle even advanced cases have responded promptly to administration of 2 to 2•5 mg. per lb. It was possible that doses as small as 1 mg. per lb. were effective. 5. Administered in the incubation stage of the disease in amounts approximately double the curative dose it had a marked effect upon the subsequent course of the disease. 6. Prophylactic or curative administration in doses up to 20 mg. per lb. did not interfere with immunity production. 7. Aureomycin alone or in combination with a sulphonamide is suggested at present as the drug of choice for treatment, or together with live virus for immunization. This work was facilitated by the supply in very generous quantities of aureomycin hydrochloride with sodium glycinate by the Director, Lederle Laboratories, Pearl River, N.Y., U.S.A., to whom we wish to take this opportunity of expressing our indebtedness.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Wesselsbron virus - a virus not previously described, associated with abortion in domestic animals

1. There has been isolated from a lamb a pantropic virus with neurotropic properties and a well-marked affinity for embryonic tissue. 2. In the field the vectors are mosquitoes which have yet to be identified accurately. 3. In sheep infection with the virus causes a febrile reaction after a short incubation period of about one to four days, the mortality rate not being high. Pregnant ewes may abort during the febrile reaction in which case virus could not be isolated from the foetuses. Subsequently the virus invades the foetus causing death usually with abortion. The mortality amongst foetuses carried to full term and new-born lambs is very high (practically 100%). New born lambs suckling reacting ewes did not become infected by contact with the reacting ewe. 4. In addition to sheep, cattle, horses, pigs, mice, rabbits, guinea-pigs and man are susceptible. 5. Infant and adult mice are equally susceptible to intracerebral inoculation, the mortality being 100%. Infant mice are fully susceptible to intraperitoneal infection but in adult mice the reaction is at most inapparent.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Experimental infection of game animals with lumpy skin disease virus (prototype strain Neethling)

Calves of a giraffe, an impala, two buffaloes, and two adult black wildebeests were artificially infected with the Neethling type of lumpy skin disease virus. The giraffe and impala died with typical symptoms and lesions of the disease. Virological examinations confirmed the presence of lumpy skin disease virus in lesions of these animals. Histopathological studies revealed microscopic lesions typical of those reported in cattle suffering from lumpy skin disease. Both intracytoplasmic and intranuclear inclusions were noticed in various cell types and some additional histopathological changes are reported. Neither the wildebeests nor the buffaloes reacted clinically to artificial infection and they failed to show a rise in antibody titre subsequently.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format..mn201

The optimal conditions for the multiplication of Neethling-type lumpy skin disease virus in embryonated eggs

Maximum yields of lumpy skin disease virus were obtained in the chorio-allantoic membranes of 5- to 7-day embryonated eggs incubated at 33.5° to 35°C for 5 to 6 days. The route of inoculation did not significantly affect the growth pattern of the virus. There was no correlation between yield of virus and the appearance of lesions in the chorioallan toic membranes. Lesions were only produced in the membranes of 7- to 9-day embryonated eggs inoculated onto the membrane and incubated at 33 .5° and 35°C.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format