A malignant catarrhal fever-like disease in red deer (Cervus elaphus) in New Zealand

Two case histories are presented to illustrate the clinical and pathological findings of a malignant catarrhal fever-like disease as seen in farmed red deer in New Zealand. Attention is drawn to the similarities with some exotic diseases and the suggestion is made that deer may act as a reservoir for the aetiological agent.     

Experimental transmission of malignant catarrhal fever to red deer (Cervus elaphus)

Abstract

Malignant catarrhal fever was transmitted from affected to recipient red deer (Cervus eluphus) using bloodor lymphoid suspension as inoculum. Incubation periods ranged from 11 to 26 days. The disease was also transmitted using lymphoid suspension stored overnight at 4°C or at ?70°C for 8 months.

The experimental disease was characterised by fever, depression, anorexia, diarrhoea and dysentry. The course of the disease was approximately 96 hours.

Major lesions consisted of acute mesenteric lymphadenitis and acute haemorrhagic typhlitis and colitis. Lesions in the caecum and colon started as multifocal mucosal haemorrhages and progressed rapidly to massive mucosal haemorrhage.     

Experimental transmission of malignant catarrhal fever to red deer (Cervus elaphus)

Malignant catarrhal fever was transmitted from affected to recipient red deer (Cervus elaphus) using blood or lymphoid suspension as inoculum. Incubation periods ranged from 11 to 26 days. The disease was also transmitted using lymphoid suspension stored overnight at 4 degrees C or at -70 degrees C for 8 months. The experimental disease was characterised by fever, depression, anorexia, diarrhoea and dysentry. The course of the disease was approximately 96 hours. Major lesions consisted of acute mesenteric lymphadenitis and acute haemorrhagic typhlitis and colitis. Lesions in the caecum and colon started as multifocal mucosal haemorrhages and progressed rapidly to massive mucosal haemorrhage.     

Parapoxvirus infections in New Zealand farmed red deer (Cervus elaphus)

Outbreaks of infection due to a parapoxvirus were reported on eight New Zealand deer farms. Scabby lesions were seen variably on the muzzle, lips, face, ears and neck of red deer (Cervus elaphus) with morbidity rates reaching 100%. On three farms multifocal lesions were also present on the velvet. Deaths were reported on two properties where the lesions were extensive and secondary bacterial infections had occurred. On one of these farms multifactorial disease was suspected. Poxvirus particles were seen by negative contrast electron microscopy in scab material from all eight properties. Morphologically the deer virus resembled a parapoxvirus, but restriction endonuclease analysis showed its DNA fragment patterns were distinct from those of orf (contagious ecthyma) virus.     

Changes in blood coagulation parameters of red deer (Cervus elaphus) experimentally infected with malignant catarrhal fever

Changes in blood coagulation parameters were followed in four red deer (Cervus elaphus) experimentally infected with malignant catarrhal fever (MCF) of deer. Blood platelet counts, activated partial thromboplastin time (APTT), one-stage prothrombin time (OSPT), activated clotting time (ACT), plasma anti-thrombin III (ATIII) activity, fibrinogen degradation production (FDP) and fibrinogen levels were measured. Inoculated deer became pyrexic after 17 or 19 days. Thereafter they developed watery diarrhoea which rapidly became haemorrhagic. The course of the clinical disease ranged from four to six days before the animals were killed or died. All inoculated deer developed abnormalities in laboratory parameters of blood coagulation. These varied within and between animals, but the coagulation profiles of all four animals remained abnormal until death. Post-mortem findings included extensive systemic petechiation, severe haemorrhage in the alimentary canal and vasculitis with disseminated thrombosis. Abnormal coagulation parameters included extension of APTT and OSPT, increased FDP, decreased ATIII and platelet counts and increased fibrinogen levels. The increases in fibrinogen were compatible with the acute phase response. The other coagulation abnormalities and haemorrhage and thrombosis were indicative of disseminated intravascular coagulation (DIC) with consumption coagulopathy, ACT remained normal in all deer although final clot quality was considered poor.     

An outbreak of malignant catarrhal fever in red deer (Cervus elephus)

Nine of 15 housed red deer developed an acute disease. Six died and three were killed when severely affected. The clinical and post mortem changes suggested a diagnosis of malignant catarrhal fever (MCF) which was consistent with the pantropic lymphoproliferative histopathological lesions observed. Attempts to isolate an agent or transmit the condition to cattle failed. The relation of the vasculitis to the pathogenesis of the disease and the susceptibility of red deer are discussed.     

Experimental tuberculosis in red deer (Cervus elaphus)

This study was designed to investigate experimental Mycobacterium bovis infection of red deer (Cervus elaphus). Three intravenously inoculated deer (dose 10µg–1000µg) developed miliary tuberculosis of the lungs and all died within 28 days of being infected. No clinical illnesses were observed in four subcutaneously (dose 1 uµg–100uµg) and three intratracheally (dose lµg–100µg) inoculated deer. At the conclusion of the experiment six weeks post inoculation, these seven animals reacted to 2 mg/ml of bovine purified protein derivative. The principal lesions in the intravenously inoculated deer were in the lungs which had multiple foci of necrosis containing very large numbers of acid fast bacilli. A gradation of changes was seen in the subcutaneously inoculated deer. The animal receiving the 1µg dose only had lesions at the injection site and the draining prescapular lymph node. Deer receiving higher doses also had histopathological changes in the lungs and liver. Microscopic changes in the intratracheally infected animals were restricted to the thoracic cavity. The ability of the deer to control infection was related to the route of inoculation.     

Experimental tuberculosis in red deer (Cervus elaphus)

This study was designed to investigate experimental Mycobacterium bovis infection of red deer (Cervus elaphus). Three intravenously inoculated deer (dose 10 microg-1000 microg) developed miliary tuberculosis of the lungs and all died within 28 days of being infected. No clinical illnesses were observed in four subcutaneously (dose 1 microg-1000 microg) and three intratracheally (dose 10 microg-100 microg) inoculated deer. At the conclusion of the experiment six weeks post inoculation, these seven animals reacted to 2 mg/ml of bovine purified protein derivative. The principal lesions in the intravenously inoculated deer were in the lungs which had multiple foci of necrosis containing very large numbers of acid fast bacilli. A gradation of changes was seen in the subcutaneously inoculated deer. The animal receiving the 1 microg dose only had lesions at the injection site and the draining prescapular lymph node. Deer receiving higher doses also had histopathological changes in the lungs and liver. Microscopic changes in the intratracheally infected animals were restricted to the thoracic cavity. The ability of the deer to controlled infection was related to the route of inoculation.     

Tuberculosis in imported red deer (Cervus elaphus)

An outbreak of tuberculosis due to Mycobacterium bovis in farmed red deer imported from an eastern European country is described. Twenty-six of the 106 deer examined at autopsy were found to be infected and 19 had visible lesions of tuberculosis. Single comparative intradermal tuberculin tests on 51 deer showed that the test had a specificity of 61.3 per cent and a sensitivity of 80 per cent relative to subsequent biological and cultural tests on tissues taken at autopsy. Three hundred and seventy eight culled fallow and sika deer which had been running in a park in contact with some of the infected animals were found to be free of tuberculosis.     

Epidemiology and pathogenesis of Mycobacterium bovis infection of red deer (Cervus elaphus) in New Zealand

AIMS: This study was initiated to investigate aspects of the epidemiology, pathogenesis and transmission of tuberculosis in wild red deer, with the aim of determining whether this species may be considered a reservoir host of Mycobacterium bovis in New Zealand. METHOD: One hundred and six wild red deer (Cervus elaphus) carcasses from the Castlepoint and Hauhungaroa Range areas, which are endemic for bovine tuberculosis, were examined for the presence of M. bovis infection. Samples were also examined from 46 skin test-positive farmed deer killed at two deer slaughter premises. Where possible, a standard set of tissues and excretion site samples was collected for mycobacteriological examination. RESULTS: Fifty-eight infected deer were identified, and of these 28% showed no gross lesions. The prevalence of tuberculosis confirmed by culture in the wild deer was 32%. Only one of 18 deer younger than 1 year was infected. Mature deer (>2 years) were 12 times more likely to be infected than those under 1 year of age. Infected older deer were less likely to show typical gross lesions than younger animals. Mycobacterium bovis was isolated from the oropharyngeal tonsil of 34 of 56 (61%) of the infected deer, and this was the most commonly infected site. Gross lesions were found in 18 of the 34 infected tonsils and only one of these showed a purulent tonsillitis. Mycobacterium bovis was recovered from four of 53 nasopharyngeal tonsils, four of 53 oropharyngeal swabs, one of 53 tracheal and nasal swabs, and one of 46 faecal samples, but not from any urine specimens. CONCLUSION: These findings suggest that significant bacillary excretion from infected deer was uncommon, and is more likely to occur in severely affected animals. This study has confirmed the importance of mucosa-associated lymphoid tissues (MALT), particularly the oropharyngeal tonsil, in the pathogenesis of tuberculosis in deer. The findings justify investigation of the hypotheses that the prevalence of tuberculosis in wild deer in New Zealand is high due to transmission of infection from possums, and that in the absence of an infected possum population, the prevalence of tuberculosis in deer is likely to be low, and spatially patchy. CLINICAL RELEVANCE: The results suggest that about one quarter of infected deer show no detectable gross lesions. This implies that many infected carcasses may enter the food chain unrecognised and that the estimated sensitivity and specificity of diagnostic tests may be erroneous if there is a difference in test performance between those conducted on deer with or without gross lesions. Diagnostic sensitivity following slaughter may be improved by routine culture of oropharyngeal tonsils and careful examination of lungs for adhesions and small subpleural tubercles.     

Electrical stunning of red deer (Cervus elaphus)

Eighteen of 23 red deer (Cervus elaphus) at a deer slaughtering premises were successfully stunned with an apparatus modified from that normally used to stun sheep. The five unsuccessful electrical stuns were associated with poor head restraint and poor head contact by the electrodes. The median stunning current was 0.9 A, and in the majority of cases the duration of stunning was less than 1 second. The signs of the electrically induced epileptiform seizures in the deer were dissimilar to those seen in sheep, cattle and pigs, in that the initial tonic phase was less marked, and of shorter duration. A similar shorter and less obvious tonic phase was noted in four deer shot with a captive bolt pistol. Two animals which were electrically stunned, and bled within 10 seconds, showed no signs of recovery while bleeding. The electroencephalograms of four deer stunned with currents of 1.3 A for a duration of either 0.5 or 1.0 seconds were recorded under more controlled conditions. All four animals developed electroencephalograms typical of an epileptiform seizure. The animals exhibited behavioural reactions similar to the other 18 animals in the trial at the deer slaughtering premises and were rendered unconscious for between 54 and 122 seconds. The electroencephalogram activity amplitude was greater than that recorded immediately before stunning and took between 6 and 9 seconds to build up to maximum value. It is concluded that, providing the heads of deer are adequately restrained, head-only electrical stunning can be incorporated into a humane method of slaughter for deer.     

Pharmacokinetics of ceftiofur in red deer (Cervus elaphus)

Twelve adult female red deer (Cervus elaphus) were given 250 mg of ceftiofur sodium by intramuscular injection (i.m.) and ballistic implant in a crossover design. Blood samples were taken from an in-dwelling jugular catheter prior to drug administration and at 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36, 48, and 72 h postadministration of the drug. Samples were centrifuged and plasma kept frozen at -70 degrees C until analysis for ceftiofur and active metabolites using an HPLC method. The pharmacokinetics of ceftiofur and metabolites after i.m. dosing and following ballistic implant were quite different. Absorption after i.m. injection was rapid; whereas following ballistic implant there was a lag-time until concentrations were detectable in plasma. The maximum concentration reached in plasma was higher following injection compared with ballistic implant, however the AUC calculated after ballistic implant was almost identical to the mean AUC found after i.m. dosing. The results indicate that i.m. administration of ceftiofur maintains adequate plasma levels for most susceptible bacterial pathogens for at least 12 h; therefore twice daily administration is needed in red deer. Ballistic implants produced plasma concentrations above the MIC for most bacterial pathogens from 4 to 24 h in most animals after administration; however, absorption of the drug was variable and some did not maintain effective concentrations for more than a few hours. Ceftiofur is a useful drug in red deer and twice daily i.m. administration dosing should allow treatment for susceptible bacterial pathogens.     

Pharmacokinetics of oxfendazole in red deer (Cervus elaphus)

The pharmacokinetics of oxfendazole (OFZ) in red deer (Cervus elaphus) was examined. OFZ, administered per os at 4.53 mg kg-1, was extracted in ether from plasma and identified and concentrations estimated by high pressure liquid chromatography. Irrespective of whether the animals were fed concentrates indoors as pellets or grass while on pasture, OFZ was absorbed rapidly. Concentrations of OFZ in plasma reached maxima within 20 hours (0.83 and 1.005 mg litre-1 respectively) and were undetectable 36 hours after administration. Fenbendazole was not detected at any time in the chromatograms. Metabolism of OFZ occurred rapidly producing the sulphone metabolite. In comparison with published data for OFZ in sheep, red deer appear to metabolise OFZ and excrete OFZ sulphone at much faster rates. Consequently, anthelmintic efficacy is likely to vary from species to species.     

Dictyocaulus infection in farmed red deer (Cervus elaphus)

Post mortem examination of red deer calves on a deer farm situated on hill ground in north-east Scotland revealed infection by a lungworm morphologically similar to Dictyocaulus viviparus. Trials were conducted to monitor the natural development of D viviparus infection in red deer, to investigate the value of a commercial lungworm vaccine and to evaluate methods of treating clinical cases. The findings indicate that the syndrome may be less apparent in red deer than it is in cattle, protection might be gained by vaccination and that housing and medication provide useful therapy. The extent of clinical disease is likely to depend on the general health, bodily condition and nutritional status of the animals versus the weight of infection acquired from the pasture. However, various factors can affect both sides in this confrontation.     

Babesias of red deer (Cervus elaphus) in Ireland

ABSTRACT: Blood samples were obtained from 38 wild red deer (Cervus elaphus) at two sites in Ireland and subjected to PCR analysis of the 18S rRNA gene followed by sequencing. Two fragments of the 18S rRNA gene were generated by two different PCR protocols and subsequent sequencing suggested that at least six of the deer were infected by a babesia that, in those loci, is indistinguishable from Babesia divergens, an important tick-borne pathogen of cattle and of zoonotic significance. Additionally, a B. odocoilei-like parasite was detected in three samples and a babesia that did not match any sequences in the GenBank database was found in five samples. Neither B. capreoli nor B. venatorum (EU1) were found. There have been several reports of B. divergens occurring in deer species, including red deer, roe deer (Capreolus capreolus) and reindeer (Rangifer tarandus). However, in view of recent re-sequencing of bovine-origin samples deposited previously in GenBank, it is unlikely that any of these sequences from deer are B. divergens. The present study describes the only deer piroplasm detected so far that shows complete identity with B. divergens, in just over half of the 18S rRNA gene. The entire gene of this deer parasite should be analysed and transmission experiments undertaken before the infectivity of B. divergens for red deer can be confirmed.     

Selenium supplementation of young red deer (Cervus elaphus)

Two selenium (Se) supplementation trials were conducted in successive years involving a total of 70 red deer calves 3-15 months of age grazing pasture containing 30-57 ppb of Se on a dry matter basis. The trials compared growth rate, whole blood Se and glutathione peroxidase (GSHpx) concentrations of calves which received periodic doses of oral Se or a single injection of barium selenate (equivalent to 50 mg Se) or no Se supplementation. There were no significant weight gain differences between treated and untreated groups in either trial. Whole blood GSHpx levels were strongly correlated with blood Se levels (r = 0.9278) and produced the following regression equation: GSHpx = 0.0155 Se - 2.292. In both years the 3 month old calves had GSHpx levels of 6-9 kU/I which probably derived from maternal transfer of Se. The GSHpx levels in unsupplemented calves declined from these levels to a minimum in winter (group means approximately 2.6) and then progressively rose the following spring and summer. Periodical oral dosing with Se or a single injection of barium selenate significantly elevated blood Se and GSHpx levels throughout the trials.     

Selenium supplementation of young red deer (Cervus elaphus)

Abstract

Two selenium (Se) supplementation trials were conducted in successive years involving a total of 70 red deer calves 3–15 months of age grazing pasture containing 30–57 ppb of Se on a dry matter basis. The trials compared growth rate, whole blood Se and glutathione peroxidase (GSHpx) concentrations of calves which received periodic doses of oral Se or a single injection of barium selenate (equivalent to 50 mg Se) or no Se supplementation. There were no significant weight gain differences between treated and untreated groups in either trial. Whole blood GSHpx levels were strongly correlated with blood Se levels (r = 0.9278) and produced the following regression equation: GSHpx 0.0155 Se ? 2.292.

In both years the 3 month old calves had GSHpx levels of 6–9 kU/l which probably derived from maternal transfer of Se. The GSHpx levels in unsupplemented calves declined from these levels to a minimum in winter (group means ? 2.6) and then progressively rose the following spring and summer.

Periodical oral dosing with Se or a single injection of barium selenate significantly elevated blood Se and GSHpx levels throughout the trials.