African Journals Online
Journal of the South African Veterinary Association

Volume 73 Number 4 December 2002
ABSTRACTS

Diagnosis and medical treatment of otitis externa in the dog and cat: review article

Jacobson, L.S.

Abstract: Otitis externa is no longer viewed as an isolated disease of the ear canal, but is a syndrome that is often a reflection of underlying dermatological disease. Causes are classified as predisposing (increase the risk of otitis) ; primary (directly induce otitis), secondary (contribute to otitis only in an abnormal ear or in conjunction with predisposing factors) and perpetuating (result from inflammation and pathology in ear, prevent resolution of otitis). Common primary causes include foreign bodies, hypersensitivity (particularly atopy and food allergy), keratinisation disorders (most commonly primary idiopathic seborrhoea and hypothyroidism) and earmites, particularly in cats. A systematic diagnostic procedure is required to identify causes and contributing factors. This should include history, clinical examination, otoscopy and cytology in all cases and culture and sensitivity as well as otitis media assessment and biopsy in severe and recurrent cases. Ancillary tests may be required depending on the underlying cause. Treatment consists of identifying and addressing predisposing and primary factors; cleaning the ear canal ; topical therapy ; systemic therapy where necessary ; client education ; follow-up ; and preventive and maintenance therapy as required.

An investigation into the usefulness of a rostrocaudal nasal radiographic view in the dog

Kirberger, R.M.; Fourie, S.L.

Abstract: A rostrocaudal (RCd) nasal view was developed in large breed mesaticephalic dogs using a complete, subsequently sectioned, skull and cadaver specimens to optimise the radiographic technique and evaluate normal anatomic features. Gelatin was placed in one nasal passage of the cadaver specimens to mimic the effects of nasal pathology. The latter specimens and 18 clinical cases with suspected nasal disease were evaluated to determine the usefulness of the RCd view compared to standard nasal views. An optimal RCd view was obtained with the dog in dorsal recumbency and the head symmetrically positioned with the hard palate perpendicular to the table using a table top technique with 8: 1 grid, collimating to the nasal region and centring the primary beam on the philtrum. The dorsolateral aspects of the maxillary bone, the nasal bones, septal sulcus of the vomer, mucosa lined nasal septum and conchae could be seen. A centrodorsal more radiolucent area representing the ethmoid bone region was also visible. Gelatin soft tissue opacification of the nasal passage could be seen more clearly in RCd nasal view than in occlusal dorsoventral view. In clinical cases the RCd view was useful to build up a 3-dimensional image of nasal passage pathology as well as to detect nasal septum and osseous nasal border pathology not visible in other views. This view is particularly useful in cases where cross-sectional imaging modalities are not available or where the nasal investigation is limited by cost considerations.

Raising livestock in resource-poor communities of the North West Province of South Africa - a participatory rural appraisal study

Getchell, J.K.; Vatta, A.F.; Motswatswe, P.W.; Krecek, R.C.; Moerane, R.; Pell, A.N.; Tucker, T.W.; Leshomo, S.

Abstract: A participatory research model was used in six village communities in the Central Region of the North West Province of South Africa in order to achieve the following broad objectives: to obtain information on the challenges owners face in raising livestock in these areas and to evaluate the livestock owners' level of knowledge of internal parasites in their animals. Information obtained at participatory workshops clearly indicated a need for improvements in water supply, schools, job creation, and health services. Lack of pasture for grazing livestock was also cited as being important. Other most frequently mentioned livestock problems included 'gall sickness' (a vaguely defined condition not necessarily referring to anaplasmosis), parasites (both external and internal), chicken diseases and ingestion of plastic bags discarded in the environment. When livestock owners were questioned during individual interviews, most were able to identify the presence of parasites in either the live or dead animal. However, it seems likely that this is limited to the identification of tapeworms. It was found that most livestock owners use a combination of treatments, ranging from traditional to folklore to commercial. There were some difficulties in using the participatory methods since it was the first time that the facilitators and the communities had been exposed to them. Many communities had difficulty in dealing with the concept of finding solutions within the community, which is such an integral part of participatory methods.

Supply of veterinary medicinal products to an emerging farming community in the North West Province of South Africa

Gehring, R.; Swan, G.E.; Sykes, R.D.

Abstract: A study was conducted in the Madikwe District of the North West Province to investigate the supply of veterinary medicinal products to small-scale, subsistence and emerging farmers. A combination of individual interviews, focus groups and direct observation was used to collect data. Stock remedies were made available to farmers within the district at Field Service Units that were managed by administrative staff of the Directorate of Field Services. The state veterinarian and animal health technicians were not directly involved with the sale of products. Most farmers still travelled to farmers' cooperatives in the larger centres outside the district to purchase the veterinary medicinal products they needed. Factors such as the quality of service provided, affordability and availability of required products as well as inaccessibility of outlets to all farmers contributed to the poor support of these outlets by the farmers of the district.

Evaluation of oestrus observation and conception rates in suckling beef cows using whole milk progesterone concentration

Lourens, D.C.; Thompson, P.N.; Bertschinger, H.J.; Ameen, M.

Abstract: A 2-sample regime was used to measure whole milk progesterone concentration on the day of oestrus and insemination (Day 0) and 6 days later (Day 6) in a sample of 50 primiparous and 100 multiparous suckling beef cows. Exposure to teaser bulls and observation by cattlemen identified the occurrence of oestrus. Three sets of criteria used to define ovulatory oestrus were compared: a) milk progesterone concentration less than 6 nmol / l on Day 0 ; b) milk progesterone less than 6 nmol / l on Day 0 and rising to greater than 6 nmol / l on Day 6; c) milk progesterone less than 6 nmol / l on Day 0 and rising to greater than 6 nmol / l on Day 6, or cow diagnosed pregnant to 1st insemination. Using only a single milk sample on Day 0 (criterion a) would have resulted in the positive predictive value of heat detection being estimated at 98.7%. Using a paired measurement (criterion b) resulted in a significantly lower estimate of 84.7%. The inclusion of cows that conceived despite not showing a marked rise in milk progesterone concentration (criterion c) resulted in a more accurate estimate of 89.3%. Use of a 2-sample regime also allowed calculation of conception rates while eliminating the effect of heat detection errors. In the cows sampled, of those in ovulatory oestrus that were inseminated, 73.1% conceived to the 1st insemination. These results demonstrate that artificial insemination within a limited breeding season can be successful if nutrition is optimal and management is intensive. The use of a 2-sample milk progesterone test may be a valuable tool in investigating heat detection and conception problems in beef herds in which artificial insemination is used.

An introductory survey of helminth control practices in South Africa and anthelmintic resistance on Thoroughbred stud farms in the Western Cape Province

Matthee, S.; Dreyer, F.H.; Hoffmann, W.A.; Van Niekerk, F.E.

Abstract: Fifty-one per cent of 110 questionnaires, designed for obtaining information on helminth control practices and management on Thoroughbred stud farms in South Africa, were completed by farmers during 2000. The number of horses per farm included in the questionnaire survey ranged from 15 to 410. Foals, yearlings and adult horses were treated with anthelmintics at a mean of 7.3+ / -3.0, 6.6+ / -2.7 and 5.3+ / -2.3 times per year, respectively. An average of 3.4 different drugs were used annually, with ivermectin being used by most farmers during 1997-2000. On 43% of farms the weights of horses were estimated by weigh band and 45% of farmers estimated visually, while both were used on 7% of farms and scales on the remaining 5%. Doses were based on average group weight on 50% of the farms and on individual weights on 46%. Forty-three per cent of farmers performed faecal egg count reduction tests (FECRT). Most farmers rotated horses between pastures and treated new horses at introduction. Faecal removal was practiced on 61% of farms and less than 50% of farmers used alternate grazing with ruminants. Faecal egg count reduction tests were done on 283 horses, using oxibendazole, ivermectin and moxidectin on 10, 9 and 5 farms, respectively, in the Western Cape Province during 2001. While the efficacy of oxibendazole was estimated by FECRT to range from 0-88% and moxidectin from 99-100%, ivermectin resulted in a 100% reduction in egg counts. Only cyathostome larvae were recovered from post-treatment faecal cultures.

Serodiagnosis of bovine cysticercosis by detecting live Taenia saginata cysts using a monoclonal antibody-based antigen-ELISA

Wanzala, W.; Onyango-Abuje, J.A.; Kang'ethe, E.K.; Ochanda, H.; Harrison, L.J.S.

Abstract: An ante mortem antigen-ELISA-based diagnosis of Taenia saginata cysticercosis was studied in artificially (n = 24) and naturally (n = 25) infected cattle with the objective of further validating the assay as a field diagnostic test. Based on total dissection as the definitive method of validity, the assay minimally detected 14 live cysticerci in artificially infected calves and 2 in naturally infected steers. In natural infections, the minimum number of live cysticerci consistently detected by Ag-ELISA was 5 while in artificial infections it was above 14. However, other animals with 12 and 17 live cysticerci in artificially infected calves, and 1 and 2 live cysticerci in naturally infected steers, escaped detection for unknown reasons. Animals harbouring dead cysticerci gave negative reactions in the assay as was the case in non-infected experimental control calves. There was a statistically significant positive linear correlation between Ag-ELISA optical density values and burdens of live cysticerci as obtained by total dissection of both artificially infected calves (r = 0.798, n = 24 ; P < 0.05) and naturally infected steers (r = 0.631, n = 25 ; P < 0.05). These results clearly show the potential effectiveness of ante mortem monoclonal antibody-based antigen detection ELISA in the diagnosis of bovine cysticercosis in cattle. Its value lies in the diagnosis of infection in cattle as a screening test in a herd, rather than as a diagnostic test at the individual level, due to false positive and negative reactions. In a herd of heavily infected cattle, the assay may, however, provide for individual diagnosis. Nevertheless, more work is recommended to increase its sensitivity so as to be able to diagnose light infections consistently in the field.

Magnetic resonance imaging of a cerebral cavernous haemangioma in a dog: clinical communication

Schoeman, J.P.; Stidworthy, M.F.; Penderis, J.; Kafka, U.

Abstract: A 13-month-old, neutered, male Golden retriever presented with seizures and progressive depression. Clinical and neurological assessment was consistent with severe intracranial disease. The neurological condition progressively deteriorated and magnetic resonance imaging (MRI) revealed the presence of a large, contrast-enhancing, space-occupying mass in the right cerebral hemisphere. Therapy with corticosteroids, mannitol and furosemide ameliorated the signs of depression and ataxia, but the owner elected euthanasia after 1 week. Post mortem examination of the brain confirmed the presence of a large haemorrhagic lesion in the right olfactory lobe, the histopathological appearance of which was consistent with cerebral cavernous haemangioma. This is the 1st case describing the MRI appearance of a cavernous haemangioma of the cerebrum in the veterinary literature.

Tremorgenic neuromycotoxicosis in 2 dogs ascribed to the ingestion of penitrem A and possibly roquefortine in rice contaminated with Penicillium crustosum: clinical communication

Naude, T.W.; O'Brien, O.M.; Rundberget, T.; McGregor, A.D.G.; Roux, C.; Flaoyen, A.

Abstract: Two dogs developed alarming tremorgenic nervous stimulation shortly after ingesting discarded rice that had been forgotten in a refrigerator for an undetermined period and that was covered with a grey-green mould. Both dogs exhibited vomition followed by slight salivation, tremors and ataxia and 1 showed such severe agitation and seizures that it necessitated anaesthesia with thiopentone followed, on recovery, by xylazine. The other dog was only sedated with xylazine. They made an uneventful recovery. The rice vomitus yielded a pure culture of Penicillium crustosum. On chemical analysis it was negative for organochlorine, organophosphor and carbamate insecticides, as well as for strychnine, but contained 2.6 mg / g of the mycotoxins penitrem A as well as 34 mg / g of roquefortine as determined by LC-MS and confirmed by MS-MS. This is the 1st South African case of naturally occurring penitrem A toxicosis and also the 1st case where quantification of the levels of mycotoxins in dog vomitus is reported. The tremorgenicity of roquefortine and its contribution towards this syndrome, is questioned.

Electrical nerve stimulation as an aid to the placement of a brachial plexus block: clinical communication

Joubert, K.E.

Abstract: Most local anaesthetic blocks are placed blindly, based on a sound knowledge of anatomy. Very often the relationship between the site of deposition of local anaesthetic and the nerve to be blocked is unknown. Large motor neurons may be stimulated with the aid of an electrical current. By observing for muscle twitches, through electrical stimulation of the nerve, a needle can be positioned extremely close to the nerve. The accuracy of local anaesthetic blocks can be improved by this technique. By using the lowest possible current a needle could be positioned within 2-5mm of a nerve. The correct duration of stimulation ensures that stimulation of sensory nerves does not occur. The use of electrical nerve stimulation in veterinary medicine is a novel technique that requires further evaluation.

Cerebral cysticercosis in a cat: clinical communication

Schwan, E.V.; De Scally, M.P.; Van Rensburg, C.L.; Durand, D.T.

Abstract: The metacestode of Taenia solium, Cysticercus cellulosae, was recovered from the brain of a cat showing central nervous clinical signs ante mortem. This is the first record of cerebral cysticercosis in a cat in South Africa.

Microsatellite analysis of cryopreserved stallion semen stored on FTA^(R) paper: research communication

Schulman, M.L.; Harper, C.K.; Bell, E.; Nel, A.; Guthrie, A.J.

Abstract: The aim of this study was to establish and validate a method to permit microsatellite analysis of DNA profiles obtained from frozen-thawed stallion sperm cells. This would provide reliable and accurate verification of the identification of a semen donor. Ejaculates from 5 pony stallions were collected, processed and frozen in 0.5 m plastic straws. Aliquots of 100 m of the frozen-thawed semen thus obtained were either placed directly, or diluted (1: 10 ; 1: 100 ; and 1: 1000) and placed on slides of FTA^(R) paper. Similarly, blood samples obtained from each of the stallions were placed onto slides of FTA^(R) paper. A punch was removed from each sample after drying. Each sample was mixed with FTA^(R) purification reagent, Dithiothreitol and Proteinase K before incubation and processing. All samples were processed with a set of 13 microsatellite markers. Further analysis permitted a comparison of the DNA profiles of the frozen-thawed semen and the blood samples. A full profile of markers was obtained from the 1: 10 and 1: 100 dilutions of the frozen-thawed semen samples as well as from the blood samples. The DNA profiles from the frozen-thawed semen and blood samples obtained from the stallions matched in all cases.

A survey of trypanosomosis in Zambian goats using haematocrit centrifuge technique and polymerase chain reaction: short communication

Ahmadu, B.; Lovelace, C.E.A.; Samui, K.L.

Abstract: The incidence of trypanosomosis was determined using the haematocrit centrifuge technique (HCT) as well as polymerase chain reaction (PCR) on 120 goat blood spots on filter paper. Both techniques failed to detect a positive reaction, implying that factors such as age, healthy appearance and small sample size notwithstanding, trypanosomosis does not seem to pose a serious threat to goat health in the districts from where the animals originated.

Overview of suspected adverse reactions to veterinary medicinal products reported in South Africa (March 2001 - February 2002): report

Naidoo, V.; Gehring, R.

Abstract: An overview of reports of suspected adverse drug reactions received by the Veterinary Pharmacovigilance and Medicines Information Centre during the period March 2001 to February 2002 is given. A total of 77 reports were received. The majority of reports involved suspected adverse reactions that occurred in dogs and cats. Most products implicated in the reports were Stock Remedies. The products were predominantly administered either by veterinarians or trained paraveterinary professionals. Although the majority of reports were received from veterinary pharmaceutical companies, the proportion of reports received directly from veterinarians increased compared with previous years.