Journal of the South African Veterinary Association 2021-12-03T12:57:44+00:00 Robyn Marais Open Journal Systems <p>The <em>Journal of the South African Veterinary Association</em> is a contemporary multi-disciplinary scientific mouthpiece for Veterinary Science in South Africa and abroad. It provides veterinarians in South Africa and elsewhere in the world with current scientific information across the full spectrum of veterinary science. Its content therefore includes reviews on various topics, clinical and non-clinical articles, research articles and short communications as well as case reports and letters.</p> Reviewer Acknowledgement 2021-11-29T13:41:18+00:00 Editorial Office <p>The Journal of the South African Veterinary Association recognises the value and importance of the peer reviewer<br>in the overall publication process – not only in shaping the individual manuscript, but also in shaping the<br>credibility and reputation of our journal.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Salivary gland enlargement and sialorrhoea in dogs with spirocercosis: A retrospective and prospective study of 298 cases 2021-11-29T12:07:59+00:00 Liesel L van der Merwe Jevan Christie Sarah J Clift Eran Dvir <p>This longitudinal cross-sectional clinical study investigated the incidence of sialorrhoea in dogs with spirocercosis and determined whether breed, body weight and the extent of the oesophageal involvement was associated with this presentation. A retrospective analysis was performed on the medical records of 233 dogs and information pertaining to 65 dogs was collected as part of a prospective study. All the animals were client-owned. Patients from the retrospective study underwent thoracic radiography or oesophageal endoscopy to diagnose and characterise the infection and were placed on therapy with a macrocyclic lactone, whereas the patients in the prospective study had both radiography and endoscopy routinely performed and biopsies of the oesophageal nodules collected where possible. Tru-cut biopsies of affected salivary glands were taken in 10 of 13 patients demonstrating clinical signs of sialorrhoea and salivary gland enlargement. The entire salivary gland was sectioned in an additional three dogs with spirocercosis and no sialorrhoea that were presented for <em>post mortem</em> examination. Sialorrhoea was present in 33/298 cases (11%). Fox terrier breeds were over-represented in the patients with sialorrhoea, comprising 36% of cases, whereas they only comprised 1.5% of the patients without sialorrhoea (p &lt; 0.001, chi squared test) and 5% of the combined group. Dogs weighing 12 kg or less were significantly over-represented in the sialorrhoea group, 69% versus 19.5% (p &lt; 0.001, chi square test). Age was not significantly different between the two groups (p &lt; 0.08, Mann-Whitney test). The number of oesophageal nodules per case was significantly higher in the non-sialorrhoea cases (p = 0.048, Mann-Whitney test). The prevalence of distal<br>oesophageal and lower oesophageal sphincter involvement, and neoplastic transformation of the nodules were not statistically different between the two groups. None of the fox terriers in either group showed neoplastic transformation of the parasitic nodules even though they were over-represented as a breed. Mandibular salivary glands were affected in 86% of cases showing sialorrhoea. Histopathology revealed acinar hyperplasia in all cases with concurrent necrosis detected in only two cases. Sialorrhoea and salivary gland enlargement has an incidence of 11% (33/298 cases) in canine spirocercosis. Small breeds (≤ 12 kg) and particularly fox terrier breeds are over-represented in the group demonstrating sialorrhoea and this appeared to be the only risk factor. The conclusion was that sialorrhoea secondary to canine spirocercosis occurs frequently and its presence should prompt further investigation for oesophageal and gastro-intestinal disease. Severely affected patients can be managed with phenobarbitone to control the dysphagia in addition to the routine macrocyclic lactones treatment.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Prevalence of pansteatitis in African sharptooth catfish, Clarias gariepinus (Burchell), in the Kruger National Park, South Africa 2021-11-29T11:52:25+00:00 K. David A Huchzermeyer <p>Pansteatitis was confirmed in sharptooth catfish, <em>Clarias gariepinus</em> (Burchell), from three main locations within the Kruger National Park (KNP); the Olifants River Gorge, Engelhard Dam on the Letaba River and from the Sabie River in the Sabiepoort. An increasing prevalence of pansteatitis was observed in catfish during repeated samplings from the Olifants Gorge from 2009 to 2011 and co-existence of old and recent lesions indicated on-going incitement of pansteatitis. Only a low prevalence of pansteatitis was observed in catfish sampled from the Olifants River upstream of the Gorge in the KNP and no pansteatitis was observed in catfish sampled from a rain-filled dam not connected to the Olifants River. Common to both the Olifants Gorge and the Sabiepoort is the damming of the rivers in Mozambique to form lakes Massingir and Corumana respectively. Anthropogenic activities resulting in potential pollution of the rivers differ greatly between these two catchments, providing argument against a primary pollution-related aetiology of the pansteatitis found at these two sites. Compared with other sites, analysis of stomach contents of catfish from the Olifants Gorge and the Sabiepoort strongly suggested that consumption of a predominantly fish diet was associated with the development of pansteatitis in these fish. In a farmed population of catfish used as positive control, development of pansteatitis could be ascribed to consumption of rancid fish waste from a trout slaughterhouse. In the Olifants Gorge, alien invasive silver carp, <em>Hypophthalmychthys molitrix</em> (Valenciennes), seasonally migrate upstream out of Lake Massingir to spawn. This schooling species is an obligate phytoplankton feeder with consequent high levels of adipose tissue n-3 polyunsaturated fatty acids. In the Olifants Gorge, at least, this may explain seasonal exposure to levels of polyunsaturated fats in the diets of catfish and crocodiles to which these animals are not adapted. The possible roles of diet, membrane lipid composition and metabolic rate of fish, sediment pollution and seasonal drop in environmental temperature in the pathogenesis of pansteatitis in the catfish are discussed. Further studies are needed to verify some of these speculations.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association The effects of adding epinephrine or xylazine to lidocaine solution for lumbosacral epidural analgesia in fat-tailed sheep 2021-12-02T13:18:08+00:00 Maryam Rostami Nasser Vesal <p>This blinded, randomised experimental study was designed to compare the analgesic effects of lumbosacral epidural administration of lidocaine-epinephrine or lidocaine-xylazine combinations in fat-tailed sheep. Nine healthy fat-tailed male lambs (mean ± s.d. age, 4.6 ± 0.4 months; weight, 24.6 kg ± 2.5 kg) were randomly allocated into four groups of six sheep: lidocaine 2% (LID), lidocaine-epinephrine 5 µg/mL (LIDEP), lidocaine-xylazine 0.05 mg/kg (LIDXY) or bupivacaine 0.5% (BUP). The onset and duration of flank, perineum and hindlimb anaesthesia and the onset and duration of hindlimb paralysis were recorded. Epidural administration of LID, LIDEP, LIDXY or BUP produced anaesthesia within 6.6 min, 7.6 min, 3.4 min and 8.4 min, respectively. The mean onset of anaesthesia in the LIDXY group was significantly shorter compared with the BUP group (p = 0.02). The mean duration of anaesthesia was 107.9 min, 190.4 min, 147.6 min and 169.7 min for LID, LIDEP, LIDXY and BUP, respectively. The onset of hindlimb paralysis was faster in the LIDXY group than in the BUP group; however, the duration of hindlimb paralysis was shorter in LIDXY compared with LIDEP. Epidural administration of LIDEP or LIDXY provides a comparable duration of local anaesthesia without any adverse effects in fat-tailed sheep. Epidural LIDXY did not appear to be advantageous over epidural LIDEP.</p> 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Survey of blackfly (Diptera: Simuliidae) annoyance levels and abundance along the Vaal and Orange Rivers, South Africa 2021-12-02T13:46:18+00:00 Chantel J de Beer Karin Kappmeier Green <p>Blackflies (Diptera: Simuliidae) are pests in the livestock and labour-intensive farming systems along the major rivers in South Africa. Since 1995, blackflies have been controlled in the Orange River with the larvicide <em>Bacillus thuringienses</em> var. <em>israelensis (Bti)</em>. During 2006–2007, the views of livestock farmers concerning blackfly annoyance were determined by means of questionnaires. The results of the questionnaires were substantiated by seasonal abundance surveys of the sub-adult stages of blackflies, conducted in 2007 at 13 sites in the Orange River and 11 sites in the Vaal River. More than half (52%) of the 39 participating farmers along the Orange River and 79% of the 52 participating farmers along the Vaal River stated that they experienced severe blackfly problems. The majority of farmers were unaware of the availability of products that could be used to protect their animals against blackfly attacks and were willing to be involved in blackfly research. High numbers of blackfly sub-adult stages found in both rivers supported the high annoyance levels reported by the respondents. <em>Simulium chutteri, Simulium damnosum</em> s.l., <em>Simulium hargreavesi, Simulium adersi</em> and <em>Simulium </em><em>alcocki</em> were identified at Christiana and Delportshoop on the Vaal River, whilst <em>S. chutteri, </em><em>S. damnosum s.l., S. adersi, S. alcocki</em> and<em> Simulium gariepense</em> were identified at Marksdrift and Ses Bridge on the Orange River. Despite the extensive control of blackflies, farmers still experience problems and this contention is supported by surveys conducted along the rivers.</p> 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Technique for the collection of clear urine from the Nile crocodile (Crocodylus niloticus) 2021-12-02T14:00:08+00:00 Jan G Myburgh Fritz W Huchzermeyer John T Soley Dirk G Booyse Herman B Groenewald Lizette C Bekker Taisen Iguchi Louis J Guillette, Jr <p>Urine samples can be a very useful diagnostic tool for the evaluation of animal health. In this article, a simple technique to collect urine from the Nile crocodile (<em>Crocodylus niloticus</em>) was described, based on a similar unpublished technique developed for the American alligator <em>(Alligator mississippiensis</em>) using a canine urinary catheter. With this technique, it was possible to collect relatively clean urine samples from Nile crocodiles of different sizes using canine urinary catheters or small diameter stomach tubes. Based on the gross anatomical features of the cloaca of the Nile crocodile, it was confirmed that urine accumulates in a chamber consisting of the urodeum and coprodeum. Faecal material is stored temporarily in the very short rectum, which is separated from the urinary chamber by the rectocoprodeal sphincter.</p> 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Preliminary investigation into the ventilatory effects of midazolam in isoflurane-anaesthetised goats 2021-12-02T14:11:19+00:00 George F Stegmann Lynette Bester <p>The ventilatory effects of intravenous midazolam (MDZ) were evaluated in isofluraneanaesthetised goats. Eight female goats aged 2–3 years were fasted from food and water for 12 h. Anaesthesia was then induced using a face mask with isoflurane in oxygen, whilst the trachea was intubated with a cuffed tracheal tube and anaesthesia maintained with isoflurane at 1.5% end-tidal concentration. Ventilation was spontaneous. The goats were treated with either a saline placebo (PLC) or MDZ intravenously at 0.2 mg/kg. Analysis of variance for repeated measures was used for the analysis of data. Significance was taken at the 0.05 level. Differences between treatments were not statistically significant (p &gt; 0.05) for tidal volume, ventilation rate, tidal volume/kg (V<sub>T</sub>/kg) and end-tidal carbon dioxide partial pressure. Within treatments, V<sub>T</sub> and V<sub>T</sub>/kg differed 5 min after MDZ administration; this was statistically significant (p &lt; 0.05). The occurrence of apnoea in the MDZ-treated goats was statistically significant (p = 0.04) compared with the PLC treated goats. Intravenous MDZ at 0.2 mg/kg administered to isoflurane-anaesthetised goats may result in transient apnoea and a mild decrease in V<sub>T</sub> and V<sub>T</sub>/kg.</p> 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association The effect of high frequency sound on Culicoides numbers collected with suction light traps 2021-12-02T14:21:16+00:00 Gert J Venter Karien Labuschagne Solomon N.B Boikanyo Liesl Morey <p><em>Culicoides</em> midges (Diptera: Ceratopogonidae), are involved in the transmission of various pathogens that cause important diseases of livestock worldwide. The use of insect repellents to reduce the attack rate of these insects on livestock could play an important role as part of an integrated control programme against diseases transmitted by these midges. The objective of this study was to determine whether high frequency sound has any repellent effect on <em>Culicoides</em> midges. The number of midges collected with 220 V Onderstepoort white light traps fitted with electronic mosquito repellents (EMRs), emitting 5-20 KHz multi-frequency sound waves, was compared with that of two untreated traps. Treatments were rotated in two replicates of a 4 x 4 randomised Latin square design. Although fewer midges were collected in the two traps fitted with EMRs, the average number collected over eight consecutive nights was not significantly different. The EMRs also had no influence on any of the physiological<br>groups of <em>Culicoides imicola</em> Kieffer or the species composition of the <em>Culicoides</em> population as determined with light traps. The results indicate that high frequency sound has no repellent effect on <em>Culicoides</em> midges. There is therefore no evidence to support their promotion or use in the protection of animals against pathogens transmitted by <em>Culicoides</em> midges.</p> 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Effect of percutaneous transthoracic lung biopsy on oxidative metabolism in sheep 2021-11-29T09:25:40+00:00 Andreza A Silva Danilo O.L. Ferreira Bianca P Santarosa Adriano Dias Débora C Damasceno Roberto C Gonçalves <p>This study aimed to assess the effect of percutaneous transthoracic lung biopsy on the oxidative metabolism of sheep by measuring the oxidative stress markers of superoxide dismutase (SOD), total glutathione (GSH-t), peroxidase (GSH-Px) and thiobarbituric acid reactive substances (TBARS) in the red cells of these animals. Blood samples were collected from 20 clinically healthy sheep prior to, and 30 min after, percutaneous transthoracic lung biopsy. After biopsy, there was a significant decrease (p &lt; 0.05) in SOD and GSH-Px activity, with no significant change (p ≥ 0.05) in GSH-t and TBARS concentrations. These results showed that percutaneous transthoracic lung biopsy did not significantly affect the oxidative metabolism of sheep 30 min after the procedure, which may be used widely in this species without causing serious tissue damage.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association A survey of antimicrobial usage in animals in South Africa with specific reference to food animals 2021-11-29T09:36:53+00:00 Hayley Eagar Gerry Swan Moritz van Vuuren <p>The purpose of this study was to set a benchmark for a monitoring and surveillance programme on the volumes of antimicrobials available and consumed by animals for the benefit of animal health in South Africa. This survey was collated from data available from 2002 to 2004. The authorised antimicrobials available in South Africa were firstly reviewed. The majority of available antimicrobials were registered under the <em>Stock Remedies Act 36 1947</em>. Secondly, volumes of antimicrobials consumed were then surveyed and it was found that the majority of consumed antimicrobials were from the macrolide and pleuromutilin classes,<br>followed by the tetracycline class, the sulphonamide class and lastly the penicillin class. Results showed that 68.5% of the antimicrobials surveyed were administered as in-feed medications. 17.5% of the total volume of antimicrobials utilised were parenteral antimicrobials, whereas antimicrobials for water medication constituted 12% of the total and ’other‘ dosage forms,<br>for example the topical and aural dosage forms, constituted 1.5% of the total. Intramammary antimicrobials represented 0.04% of the total. The surveillance systems for veterinary antimicrobials used by other countries were scrutinised and compared. It was concluded that a combination of the surveillance systems applied by Australia and the United Kingdom is the best model (with modifications) to apply to the animal health industry in South Africa. Such a surveillance system, of the volumes of veterinary antimicrobials consumed, should ideally be implemented in conjunction with a veterinary antimicrobial resistance surveillance and monitoring programme. This will generate meaningful data that will contribute to the rational administration of antimicrobials in order to preserve the efficacy of the existing antimicrobials in South Africa.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Determination of the minimum protective dose for bluetongue virus serotype 2 and 8 vaccines in sheep 2021-11-29T09:43:49+00:00 Jacob Modumo Estelle H Venter <p>Recent outbreaks of bluetongue virus (BTV) serotypes 2 and 8 in many European countries provided an opportunity to investigate the possibility of improving the safety of the modified live vaccines administered mainly in South Africa. Modified live vaccines (MLV) released at a titre of 5 x 10<sup>4 </sup>PFU/mL, raised concerns and prompted the need to determine the minimum titre which will still be protective and also safe. The BTV serotypes 2 and 8 vaccines were produced at the following titres: 10<sup>2</sup> PFU/mL, 10<sup>3 </sup>PFU/mL and 10<sup>4 </sup>PFU/mL, and were injected into 24 sheep which were then monitored. Blood was collected on days 0, 3, 6, 9, 12, 15, 18, 21,<br>25, 28 and 4 months post vaccination, for seroconversion and viraemia studies. These sheep were later challenged at 4 months post vaccination using BTV infected cell culture material, they were then observed and bled and again tested for viraemia. There was no viraemia post vaccination, however, a febrile reaction did occur and seroconversion was demonstrated at low titres for both BTV 2 and 8. Although viraemia was demonstrated post challenge, sheep vaccinated with the low titre BTV 2 vaccine showed more than a 90% protection index at a lower titre of 10<sup>3 </sup>PFU/mL, compared with BTV 8 that showed a protection index above 90%<br>at all the titres used. It is recommended that for BTV 2 vaccine, sheep should be vaccinated at a titre of 10<sup>3</sup> PFU/mL and at a titre of 10<sup>2 </sup>PFU/mL with BTV 8 vaccine.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association An investigation to determine the cause of haemorrhagic enteritis in commercial pig grower units in the northern parts of South Africa 2021-11-29T10:03:55+00:00 Annemarie Labuscagne B. Tom Spencer Jackie A Picard Mark C Williams <p>Necropsies were performed on 36 grower pigs that died peracutely on farms in the northern parts of South Africa. All these pigs were suffering from haemorrhagic enteritis and suspected toxaemia. Samples of the duodenum, jejunum and ileum were taken for histopathological examination and a section of ileum was collected for microbiological examination from each animal. Histological lesions characteristic of enterotoxigenic Clostridium infection were found. Large, Gram-positive bacilli were sometimes abundant in sections and mucosal smears of the intestine. However, only 40% of the cultures were positive for Clostridium perfringens.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Evaluation of ‘white-spotted kidneys’ associated with leptospirosis by polymerase chain reaction based LipL32 gene in slaughtered cows 2021-11-29T10:24:53+00:00 Shahrzad Azizi Elahe Tajbakhsh Mohammad R Hajimirzaei Mohssen Gholami Varnamkhast Hossein Sadeghian Ahmad Oryan <p>The presence of white spots in the kidneys of cattle at slaughter (so-called white-spottedkidneys) can be an indication of infection with <em>Leptospira</em>, a spirochaete of public health concern because it causes zoonotic disease. In this study, 24 kidneys of 180 slaughtered cows (13.3%) showed focal to multifocal white spots at inspection. These kidneys, together with matching urine (n = 18) and blood (n = 24) samples, were examined by polymerase chain reaction (PCR) targeting the <em>LipL32</em> gene. Leptospiral deoxyribonucleic acid (DNA) was detected in 19 (79.2%) out of 24 kidneys, as well as 7 (29.2%) blood and 10 (55.5%) urine samples of cows with white spots in their kidneys. Histopathological findings revealed multifocal infiltration of mononuclear cells, including lymphocytes and a few plasma cells in the renal interstitial tissues. In addition, 14 apparently normal kidneys and associated urine and blood samples were similarly examined by PCR but did not provide any positive results. In this study, high detection of leptospirosis in kidneys with interstitial nephritis suggests that <em>Leptospira</em> spp. are associated with white spotted kidneys. The present findings indicate that white spotted kidneys can be due to leptospirosis in this region in southwestern Iran, which indicates an increased risk of zoonotic disease. The data show that <em>LipL32</em>-based primers are useful for PCR-based diagnosis of leptospirosis.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Clinical evaluation of general anaesthesia in pigeons using a combination of ketamine and diazepam 2021-11-29T09:15:39+00:00 Aidin Azizpour Yashar Hassani <p>This study was undertaken to investigate the clinical effects of ketamine, diazepam and a ketamine and diazepam combination in the general anaesthesia of pigeons. Thirty-two pigeons of both sexes with body weights ranging from 280 g to 300 g were allocated randomly to four groups comprising eight birds each. Group D received a 0.5 mL mixture of diazepam (0.2 mg/kg) and normal saline, group K a 0.5 mL mixture of ketamine 5% (30 mg/kg) and normal saline, group D, group KD a 0.5 mL mixture of ketamine 5% (10 mg/kg), diazepam (0.2 mg/kg) and normal saline, whilst group C (control) received 0.5 mL of normal saline only.<br>Each mixture was administered intramuscularly. Under standard operating room conditions, general anaesthesia was not observed in group C (normal saline alone). In group D, sedation and muscle relaxation without complete loss of consciousness was observed. Induction time of anaesthesia in group KD was significantly quicker than group K (p &lt; 0.05). Duration of anaesthesia in group KD was significantly longer than group K (p &lt; 0.05). Recovery took longer in group KD in comparison with group K, but the difference was not statistically significant (p &gt; 0.05). The birds in group KD were calm and sedated, with good muscle relaxation, whilst in group K the birds were excited and showed a drop in body temperature. According to the results of this study, the combination of low dose ketamine hydrochloride (HCL) and diazepam overcame the adverse effects of ketamine alone. This combination produced a more rapid induction of anaesthesia, as well as an increase in anaesthesia duration, with good muscle relaxation and a smooth and slow recovery. Use of a combination of ketamine HCL given at 10 mg/kg and diazepam given at 0.2 mg/kg for anaesthesia in pigeons is therefore recommended.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Preliminary evaluation of selected minerals in liver samples from springbok (Antidorcas marsupialis) from the National Zoological Gardens of South Africa 2021-11-29T10:57:18+00:00 Khanyisile R Mbatha Emily P Lane Michael Lander Adrian S.W Tordiffe Sandra Corr <p>Limited information is available on the mineral nutrition of captive antelope in South Africa. Zoo animals are usually offered a very limited array of feeds, which may result in nutritional imbalances. As a pilot study to investigate the presence of myopathy in antelope at the National Zoological Gardens of South Africa (NZG), stored liver samples from six springbok (<em>Antidorcas </em><em>marsupialis</em>) and seven other antelopes from the NZG, as well as selected food items, were submitted for analysis of selenium, copper, manganese and zinc content by spectrophotometry. Springbok liver levels of copper were 23.07 mg/kg ± 0.72 mg/kg, whilst manganese, selenium and zinc levels were 6.73 mg/kg ± 0.22 mg/kg, 0.14 mg/kg ± 0.05 mg/kg and 135.02 mg/kg ± 1.26 mg/kg, respectively. Liver mineral levels in the other species were very variable. Food item copper levels ranged from 4.00 mg/kg (<em>Eragrostis tef</em>) to 17.38 mg/kg (antelope cubes), lucerne (<em>Medicago sativa</em>) and E. <em>tef</em> contained no detectable selenium. The highest zinc levels were in antelope cubes (147.00 mg/kg) and the lowest were in lucerne (20.80 mg/kg). Interpretation of these results was hampered by the small number of samples and a paucity of information on liver mineral levels in free-ranging and captive antelope; however, results suggested that, in the springbok, whilst copper and manganese intake are likely adequate, selenium nutrition is probably insufficient and may account for the myopathy diagnosed. Zinc liver levels are possibly within the toxic range, perhaps as a result of the high levels of zinc in the antelope cubes. This pilot study highlighted the need to establish baseline mineral nutrition data for captive and freeranging antelope under South African conditions.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association An investigation into an outbreak of Rift Valley fever on a cattle farm in Bela-Bela, South Africa, in 2008 2021-11-29T11:05:31+00:00 Lourenço P Mapaco Jacobus A.W Coetzer Janusz T Paweska Estelle H Venter <p>In 2008, a suspected outbreak of Rift Valley fever (RVF) was reported on a farm in the Bela-Bela area, Limpopo Province, South Africa. Seven calves died on the affected dairy farm, where no RVF vaccination programme was practised. No apparent clinical disease was reported in the other 300 cattle (33 calves included) or 200 sheep on the farm. During the outbreak, blood samples from 77.7% (233/300) of the cattle and 36.5% (73/200) of the sheep were collected on the affected farm and 55 blood samples were taken from cattle on a neighbouring farm. Eight weeks later, 78% of the cattle (234/300) and 42.5% of the sheep (85/200) were bled on the affected farm only. All sera were tested by an Immunoglobulin M (IgM)-capture Enzymelinked immunosorbent assay (ELISA) and by an indirect Immunoglobulin G (IgG) ELISA. Selected IgM-positive (n = 14), IgG-positive (n = 23) and samples negative for both IgM and IgG-specific antibodies against RVF virus (n = 19) were tested using the serum neutralisation test (SNT). Sera from IgM-positive (n = 14) and negative (n = 20) animals were also tested by a TaqMan polymerase chain reaction (PCR). On the affected farm, 7% (16/233) of the cattle were IgM-positive and 13.7% (32/233) IgG-positive at the first bleed and 2% were IgM-positive at the second bleed, whilst the number of cattle positive for IgG-specific antibodies increased by 21.3% compared with the first bleed. Only 1.4% of sheep were positive for both IgM and IgG antibodies at the first collection; at the second bleed, IgM-positive cases decreased to 1.2%, whilst IgG-positive cases increased to 2.4%. Whilst no IgM-positive cattle were found on the neighbouring farm, 5.5% of cattle were IgG-positive. The SNT confirmed most of the ELISA results, whilst PCR results were all negative. Although serology results indicated virus circulation on both farms, the negative PCR results demonstrated that the animals were not viraemic at the time they were sampled. The movement of infected mosquito vectors by wind over long distances into a low-lying area that favoured their breeding on the Bela-Bela farm may have led to an outbreak of the disease there, but the reason for the low level of virus circulation amongst susceptible animals remains unclear.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Epizootic ulcerative syndrome: Exotic fish disease threatens Africa’s aquatic ecosystems 2021-11-29T11:13:08+00:00 Karl D.A Huchzermeyer Benjamin C.W van der Waal <p>In late 2006 an unusual ulcerative condition in wild fish was reported for the first time in Africa<br>from the Chobe and upper Zambezi Rivers in Botswana and Namibia. Concern increased<br>with subsistence fishermen reporting large numbers of ulcerated fish in their catches. In April<br>2007 the condition was confirmed as an outbreak of epizootic ulcerative syndrome (EUS).<br>The causative agent, <em>Aphanomyces invadans</em>, is a pathogenic water mould of fish that shows<br>little host specificity. Ulcers follow infection of tissues by oomycete zoospores, resulting in<br>a granulomatous inflammation associated with invading oomycete hyphae. Granulomatous<br>tracts surrounding oomycete hyphae within the necrotic tissues characterise the diagnostic<br>histological picture. The upper Zambezi floodplain at the confluence with the Chobe River<br>spans the four countries of Botswana, Namibia, Zambia and Zimbabwe, making disease control<br>a challenge. The floodplain ecosystem supports a high fish diversity of around 80 species,<br>and is an important breeding and nursery ground. The annual cycle of flooding brings about<br>changes in water quality that are thought to favour the infectivity of A. <em>invadans</em>, with diseased<br>fish appearing soon after the plains become flooded. Since 2006 the disease has spread rapidly<br>upstream along the upper Zambezi and its tributaries. By 2010 the disease was reported from<br>the Okavango Delta in Botswana and in 2011 from the Western Cape Province of South Africa.<br>EUS has the potential to disrupt floodplain ecosystems elsewhere in Africa where high fish<br>diversity forms the basis of subsistence fisheries and local economies, and is a direct threat to<br>freshwater fish culture.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Aspiration lung disorders in bovines: A case report and review 2021-11-29T12:10:48+00:00 Anthony S Shakespeare <p>Lung aspiration disorders in bovines are invariably diagnosed as infectious aspiration pneumonias. There is a distinct differentiation between aspiration pneumonia and aspiration pneumonitis in humans that can be applied to bovines. The nature and quantity of the aspirate can result in differing pathogeneses which can require differing therapeutic approaches. Whilst blood gases were important in detecting and prognosticating lung problems, changes in barometric pressure with altitude have to be considered when interpreting partial pressures of oxygen. Anatomical differences in the lungs of bovines can explain why this species is more prone to certain pneumonic problems. Pulmonary physiotherapy is important in treating lung disorders in humans and should be considered as an adjunct therapy in bovine respiratory conditions. A case work-up was used to highlight some of the points discussed in this article</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Anaesthetic management of a 10-month-old white rhinoceros (Ceratotherium simum) calf for emergency exploratory celiotomy 2021-11-29T12:17:37+00:00 Gareth E Zeiler George F Stegmann <p>A 10-month-old, 580 kg, hand-reared white rhinoceros (<em>Ceratotherium simum</em>) calf was presented for emergency exploratory celiotomy. Anaesthesia was safely induced with three successive intravenous (IV) boluses of diazepam (10 mg) and ketamine (100 mg) until the trachea could be intubated. Anaesthesia was adequately maintained with isoflurane-inoxygen (mean end-tidal isoflurane concentration of 1.1% ± 0.2%) on a circle anaesthetic machine with carbon dioxide absorption and an intravenous infusion of ketamine and medetomidine at a mean rate of 0.02 mg/kg/min and 0.02 µg/kg/min, respectively. Mean values recorded during anaesthesia and surgery were heart rate (56.9 ± 11 beats/min), mean arterial blood pressure (6.16 kPa ± 1.75 kPa), end-tidal carbon dioxide concentration (6.23 kPa ± 0.30 kPa). Abdominal gas distension contributed to hypoventilation that resulted in hypercapnoea, confirmed by arterial blood gas analysis (PaCO<sub>2 </sub>14.69 kPa), which required controlled ventilation for correction. Blood volume was maintained with the intravenous infusion of a balanced electrolyte solution at 10 mL/kg/h and blood pressure supported with a continuous infusion of dobutamine and phenylephrine. Duration of anaesthesia was 3.5 h.<br>It was concluded that anaesthesia was safely induced in a compromised white rhinoceros calf with a combination of diazepam and ketamine. A constant-rate infusion of medetomidine and ketamine allowed for a reduction in the dose of isoflurane required during maintenance of anaesthesia and improved intra-operative blood pressure management.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Immunohistochemical study of a canine neurofibroma 2021-11-29T09:52:17+00:00 Hamidreza Fattahian Pejman Mortazavi Hamidreza Moosavian Roozbeh Moridpour Hamid Mohyeddin <p>Accurate diagnostic approaches to differentiate peripheral nerve sheet tumours from others have not been firmly established. The aim of this case report was to diagnose neurofibroma using a combination of diagnostic imaging, histopathology and immunohistochemistry, which were applied to a canine neurofibroma arising in the left mandible. The tumour was surgically excised and examined histologically. Round or spindle cells, with elongated, dense and homogenous chromatin and pale cytoplasm typical of Schwann cells in an abundant fibromyxomatous stroma, with ruby collagen fibres were seen. Immunohistochemistry demonstrated that S-100 and vimentin were more than 70% positive. Neurofibroma may therefore be recognisable using markers such as S-100 and vimentin.&nbsp;</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Rhabdomyosarcoma in a terrestrial tortoise (Geochelone nigra) in Nigeria: A case report 2021-11-29T11:30:49+00:00 Oghenemega D Eyarefe Richard E Antia Cecilia O Oguntoye Olusoji O Abiola Olugbenga O Alaka John. O Ogunsola <p>A skeletal muscle tumour (rhabdomysarcoma) was diagnosed in a 4-year-old captive female<br>terrestrial tortoise (<em>Geochelone nigra</em>) weighing 7 kg presented at the Veterinary Teaching<br>Hospital, University of Ibadan, Ibadan, Nigeria. The tumour was located at the anterior right<br>portion of the body and ventral to the carapace. The location of the tumour prevented the<br>tortoise from extending its head from the body. The tumour was a sessile, smooth white<br>mass, with a soft myxomatous consistency. The histological features that were diagnostic of<br>rhabdomyosarcoma included a sparse population of haphazardly arranged spindle-shaped<br>cells within a homogenous matrix (anisocytosis), occasional tumour giant and binucleate<br>cells, and some well differentiated myofibrils with cross striations within the cytoplasm. The<br>paucity of information on tumours in the land tortoise was the reason for this report, which<br>appears to be the first report of rhabdomyosarcoma in the tortoise.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Identification of ventrolateral intramedullary intervertebral disc herniation in a dog 2021-11-29T12:56:19+00:00 Masato Kitagawa Midori Okada Kiichi Kanayama Takeo Sakai <p>A 10-year-old male cross-breed dog was brought to Nihon University Animal Hospital with a history of acute onset of paralysis in the pelvic limbs 13 days previously. Magnetic resonance imaging revealed an intramedullary linear tract in the spinal cord at the thoracic vertebrae 12–13 region, which appeared hyperintense on T2-weighted images, but was hypointense and isointense on T1-weighted images when compared with normal parenchyma of the spinal cord. A hemilaminectomy was performed and a blob of what appeared to be fibrous tissue was found adhering to the surface of the <em>dura mater</em>. The diameter of the blob was about<br>4 mm. A durotomy was performed over the affected area and chondroid material was found within the spinal cord. Material from the nucleus pulposus penetrated the <em>dura mater</em> from the ventral aspect of the spinal cord in previously reported intramedullary intervertebral disc herniation cases, but, in this case, penetration occurred from the left ventrolateral aspect and progressed through to the right lateral aspect, forming a visible blob of what appeared to be fibrous tissue on the surface of the <em>dura mater</em> at the exit point. To the best of our knowledge, this was the first case report of an intramedullary intervertebral disc herniation originating from the ventrolateral aspect of the spinal cord in a dog.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Extraskeletal osteochondroma on a cat´s elbow 2021-11-29T13:01:55+00:00 Chantal Rosa Robert M Kirberger <p>A solitary extraskeletal osteochondroma was diagnosed in a 6-year-old, castrated male Burmese cat, positive for feline leukaemia virus (FeLV). The cat presented with a rapidly growing, solid, non-painful mass on the craniolateral aspect of the left elbow. Radiographs revealed an oval, well circumscribed 2.0 cm × 1.5 cm × 1.5 cm mineralised mass separated from the underlying bone. Surgical excisional biopsy confirmed the diagnosis. Feline extraskeletal osteochondromas are benign tumours frequently seen in FeLV-positive cats which can transform into osteosarcomas or chondrosarcomas. Radiographically, they cannot be distinguished from a parosteal or an extraskeletal osteosarcoma.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Morbidity and mortality following envenomation by the common night adder (Causus rhombeatus) in three dogs 2021-11-29T13:09:07+00:00 Kurt G.M de Cramer Garreth A van Bart Freek Huberts <p>In South Africa dogs are frequently presented to veterinarians following snakebite. The offending snakes are usually puff adders (<em>Bitis arietans</em>), cobras (<em>Naja</em> spp.) and mambas (<em>Dendroaspis</em> spp.). Night adder (<em>Causus rhombeatus</em>) bites in dogs have not yet been reported in South Africa. This article deals with three cases of dogs bitten by night adders in which extensive tissue damage was noted and one fatality occurred. Night adder bites may be indistinguishable from puff adder bites. Non-specific treatment included addressing the hypovolaemia and swelling. Specific treatment involving immunotherapy using the South African polyvalent antivenom would be ineffective as it does not contain immunoglobulins against night adder venom. Veterinarians should also include night adders as the possible cause of dogs suffering from severe and painful swellings suspected to be due to snakebites</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Rumenolith formation in a Bapedi ram 2021-11-29T13:14:00+00:00 Rhoda Leask Gareth F Bath <p>During a routine flock visit, a farmer observed that one of the eight tooth Bapedi rams had been losing body condition despite being separated from the flock and fed supplementary feed. The ram’s body condition score was assessed as 2 out of 5 (one point less than the average of the rest of the rams) and the teeth appeared normal with no excessive wear. The rumen was assessed by auscultation, palpation and ballottement where a foreign body (approximately 20 cm × 5 cm – 10 cm) was clearly palpated and ballotted. A rumenotomy was performed and a large mass of tightly compacted foreign matter and plant material was removed. The mass consisted of synthetic fibre, plant material and calcium phosphate (50.5%). It appeared to have formed as the result of the ingestion of a synthetic fibre which formed the nidus of a concretion. This was probably the result of deficient nutrition, with the rams eating the synthetic fibre in an attempt to increase feed intake. The ram recovered uneventfully after the<br>rumenotomy was performed and supplementary feeding.&nbsp;</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Doramectin toxicity in a group of lions (Panthera leo) 2021-11-29T13:17:51+00:00 Remo G Lobetti Peter Caldwell <p>Ten lions (<em>Panthera leo</em>) that were treated with a single injection of doramectin at a dose ranging between 0.2 mg/kg and 0.5 mg/kg showed clinical signs consistent with avermectin toxicity, namely ataxia, hallucinations, and mydriasis. Two subsequently died whereas the other eight lions recovered after 4–5 days with symptomatic therapy. Post-mortem examinations of the<br>two that died showed cyanosis, severe pulmonary oedema, pleural effusion, and pericardial effusion, with histopathology not revealing any abnormalities. In both these lions, doramectin brain and liver tissue concentrations were elevated. Although doramectin is regularly used in wild felids, to date there have been no reports of avermectin toxicity in the literature. This<br>article highlights the potential for doramectin toxicity in this species.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Avian bornavirus genotype 4 recovered from naturally infected psittacine birds with proventricular dilatation disease in South Africa 2021-11-29T13:30:58+00:00 Robert D Last Herbert Weissenböck Nora Nedorost H.L. Shivaprasad <p>The occurrence of proventricular dilatation disease caused by avian bornavirus (ABV) in<br>captive psittacine birds has long been suspected in South Africa. This report documents the first<br>detection by polymerase chain reaction and gene sequence analyses of ABV from three clinical<br>cases of proventricular dilatation disease (PDD) in captive bred blue and gold macaws (<em>Araara</em><br><em>rauna</em>) resident in this country. Lymphoplasmacytic encephalitis, gastrointestinal myenteric<br>gangioneuritis and leiomyositis were the most prominent histopathological changes and ABV<br>genotype 4 was detected in tissues from all three birds. Immunohistochemical stains for ABV<br>antigen revealed positive labelling of neurons and glial cells of the brain, myenteric ganglia<br>and nerve fibres as well as smooth muscle cells of the gastrointestinal tract of all three birds.<br>In one bird, positive labelling of the peripheral nerves was observed. The identical sequence<br>of the analaysed genome fragment of all three samples, history that all of these birds had<br>originated from the same breeding facility, and young age at presentation raise the question<br>of possible vertical transmission.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association An outbreak of canine aflatoxicosis in Gauteng Province, South Africa 2021-12-02T13:27:40+00:00 Luke F Arnot Neil M Duncan Heleen Coetzer Christo J Botha <p>Sporadic outbreaks of aflatoxicosis occur in dogs when they consume contaminated dog food. During 2011, low-cost brands of pelleted dog food were contaminated with very high concentrations of aflatoxins. Approximately 100 dogs were presented to the Onderstepoort Veterinary Academic Hospital. Clinically, the dogs were depressed to collapsed and icteric, with haematemesis, melaena and haematochezia. The most common pathological findings were icterus, gastro-enterorrhagia and hepatosis. On histopathological examination, fatty hepatosis and bile duct proliferation were observed. A consistent, very characteristic finding<br>was the presence of a blue-grey granular material within the bile ducts. A total of 124 samples of the dog food fed to the affected dogs was analysed to determine aflatoxin concentrations. Concentrations ranged from below the limit of quantification (&lt; 5 μg/kg) to 4946 μg/kg and six samples were submitted to determine the ratio of aflatoxins in the feed. It is estimated that well over 220 dogs died in the Gauteng Province of South Africa as a result of this aflatoxin outbreak.</p> 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association A reference handbook for daily use in equine practice 2021-12-02T13:31:44+00:00 Editorial Office <p>Numerous contributors have combined their expertise to produce a textbook encompassing a comprehensive range of topics in equine medicine, surgery and reproduction. As the editors have so aptly stated in their preface, it is virtually impossible to include all aspects of equine practice into a single volume. However, they should be commended on their efforts – this is a textbook that can be used daily in general equine practice, whether hospital-based or ambulatory.</p> 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Review of Bovine Anatomy 2021-11-29T10:26:23+00:00 Editorial Office <p>Review of Bovine Anatomy</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Review of Small animal dermatology 2021-11-29T09:28:48+00:00 Editorial Office <p>Review of Small animal dermatology</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Review of Acupuncture for Dogs and Cats 2021-11-29T10:06:13+00:00 Editorial Office <p>Review of Acupuncture for Dogs and Cats</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Horses: Unique senses – unique behaviour 2021-11-29T11:41:19+00:00 Editorial Office <p>Horses: Unique senses – unique behaviour</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Review of the newly released book entitled ‘Equine Pediatric Medicine’ 2021-11-29T11:46:48+00:00 Editorial Office <p>Review of the newly released book entitled ‘Equine Pediatric Medicine’</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association The history of veterinary medicine in Namibia 2021-12-02T13:37:29+00:00 Herbert P Schneider <p>Until the middle of the 19th century, very few references exist regarding the occurrence of animal diseases in Namibia. With the introduction of contagious bovine pleuropneumonia (CBPP) in 1859, this picture changed completely and livestock owners implemented various forms of disease control in an effort to contain the spread of this disease and minimise its devastating effects. After the establishment of the colonial administration in 1884, the first animal disease legislation was introduced in 1887 and the first veterinarian, Dr Wilhelm Rickmann, arrived in 1894. CBPP and the outbreak of rinderpest in 1897 necessitated a<br>greatly expanded veterinary infrastructure and the first veterinary laboratory was erected at Gammams near Windhoek in 1897. To prevent the spread of rinderpest, a veterinary cordon line was established, which was the very beginning of the Veterinary Cordon Fence as it is known today. After the First World War, a small but dedicated corps of veterinarians again built up an efficient animal health service in the following decades, with veterinary private practice developing from the mid–1950s. The veterinary profession organised itself in 1947 in the form of a veterinary association and, in 1984, legislation was passed to regulate the veterinary profession by the establishment of the Veterinary Council of Namibia. The outbreak of foot and mouth disease in 1961 was instrumental in the creation of an effective veterinary service, meeting international veterinary standards of quality and performance which are still maintained today.</p> 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association Lamsiekte (botulism): Solving the aetiology riddle 2021-11-29T11:39:35+00:00 Rudolph D Bigalke <p>The reason or reasons why it took Sir Arnold Theiler so many years to unravel the riddle of the aetiology of lamsiekte in cattle and whether P.R. Viljoen’s lifelong grudge for receiving insufficient credit from Theiler for his research contribution was justified are analysed in this paper. By 1912, Theiler knew that Duncan Hutcheon had advocated the use of bonemeal as a prophylactic against the disease in the early 1880s. Hutcheon’s colleague, J.D. Borthwick, had shown conclusively in a field experiment in 1895 that lamsiekte did not occur in cattle fed a liberal allowance of bonemeal; and bone-craving had been identified by Hutcheon and<br>several farmers as being associated with the occurrence of the disease (a ‘premonitory’ sign). Hutcheon regarded a phosphate deficiency of the pastures as the direct cause of lamsiekte. However, Theiler did not accept this, was convinced that intoxication was involved and developed a ‘grass toxin’ theory. Viljoen (1918) also latched onto the grass toxin theory. He did not believe that osteophagia existed, stating categorically that he had not observed it on the experimental farm Armoedsvlakte where &gt; 100 cases of lamsiekte had occurred during the &gt; 3 years that he spent there. Moreover, he did not believe in the prophylactic value of bonemeal. However, careful analysis of a subsequent publication, of which he was a co-author, revealed that in late 1918 and early 1919 he reproduced the disease by drenching cattle with blowfly pupae and larvae as well as with crushed bones from decomposing bovine carcasses. For this breakthrough he did not get proper credit from Theiler. Reappointed to study lamsiekte on Armoedsvlakte in the autumn of 1919, Theiler, probably already aware that the toxin he was seeking was in the decomposing bones or carcass material rather than the grass, deliberately ‘walked with the cattle’ on the farm to encounter a classic manifestationn of bone-craving (osteophagia). The penny then immediately dropped. Theiler, actually rationalising an hypothesis that was about four decades old, did so with a vengeance. Within less than two years he had reproduced lamsiekte by exposing cattle with natural bone-craving to rotten carcass material, had chemical proof that the grazing was phosphorus-deficient, had<br>developed a satisfactory bonemeal prophylactic dosage programme, and the bacterial toxin concerned – perhaps the trickiest contribution – had been produced in culture. Hence the table was set for the later development of an excellent lamsiekte vaccine.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association History of Orbivirus research in South Africa 2021-11-29T11:45:22+00:00 Daniel W Verwoerd <p>In the early colonial history of South Africa, horses played an important role, both in general transportation and in military operations. Frequent epidemics of African horsesickness (AHS) in the 18th century therefore severely affected the economy. The first scientific research on the disease was carried out by Alexander Edington (1892), the first government bacteriologist of<br>the Cape Colony, who resolved the existing confusion that reigned and established its identity as a separate disease. Bluetongue (BT) was described for the first time by Duncan Hutcheon in 1880, although it was probably always endemic in wild ruminants and only became a problem when highly susceptible Merino sheep were introduced to the Cape in the late 18th century. The filterability of the AHS virus (AHSV) was demonstrated in 1900 by M’Fadyean in London, and that of the BT virus (BTV) in 1905 by Theiler at Onderstepoort, thus proving the viral nature of both agents. Theiler developed the first vaccines for both diseases at Onderstepoort. Both vaccines consisted of infective blood followed by hyper-immune serum, and were used for many years. Subsequent breakthroughs include the adaptation to propagation and attenuation in embryonated eggs in the case of BTV and in mouse brains for AHSV. This was followed by the discovery of multiple serotypes of both viruses, the transmission of both by Culicoides midges and their eventual replication in cell cultures. Molecular studies led to the discovery of the segmented double-stranded RNA genomes, thus proving their genetic relationship and leading to their classification in a genus called Orbivirus. Further work included the molecular cloning of the genes of all the serotypes of both viruses and clarification of their relationship to the viral proteins, which led to much improved diagnostic techniques and eventually to the development of a recombinant vaccine, which unfortunately has so far been unsuitable for mass production.</p> 2021-12-03T00:00:00+00:00 Copyright (c) 2021 Journal of the South African Veterinary Association