Locking Horns with the Greater Kudu

mad cow home or moly bio area or best links

Introduction to kudu and oryx issues
Comparison of amino acid sequences
Comparison of nucleic acid sequences
DNA and protein sequences of kudu, oryx, sheep, and cow
References

Locking Horns with the Greater Kudu

The greater kudu, Tragelaphus streptsiceros, is an artiodactyl apparently very susceptible to oral transmission of BSE an possibly to lateral and/or maternal transmission: a 19-month-old greater kudu , whose dam had died of a BSE-like disorder 15 months earlier, itself had not been exposed to ruminant-derived feed. Overall, 5 out of 8 animals in a kuru herd derived from 3 animals died of TSE at one zoo. So the sequence of the greater kudu prion gene is of considerable interest.

It seems that three individual animals of this species have been sequenced with three different resulting sequences, called here A, B, and C. Sequence A was published by Poidinger M, Kirkwood J, Almond JW in Arch Virol 131 (1-2): 193-199 (1993) but never submitted to Genbank. That article also contained DNA and protein sequences for the Arabian oryx, Oryx leucoryx, that are also missing from Genbank. Sequences B and C were never published but submitted directly to the databases, by Martin,T.C., Hughes,S.L., Hughes,K.J. and Dawson,M. of the Central Veterinary Laboratory, Surrey, in August, 1993.

Sequence A is that of a zoo kudu that died of TSE (as is the oryx sequence). Neither pathology nor genealogy is clear for sequences B and C. As seen below, considerable polymorphic differences in the repeat region are reported. While it is hard to believe that each of three kudus would have a different sequence, an extra octapeptide repeat is also found in cow and human. Kudu subspecies, distinct African populations, or in-bred zoo animals could also figure in. Almond notes that cDNA from a diploid animal might just pick up a haplotype, i.e., these kudus could have more in common than it appears. There are also many opportunities for errors with repeated DNA, from initial amplification, to the reading of gels, to recording of data, to copying, editing, or transmissal of sequence text, as happened with primate sequences.

Closely related species (with BSE involvement but no sequence data) include the lesser kudu, Tragelaphus imberbis, with its reduced chromosome count of 38 with X and Y chromosomes showing autosomal fusions; nyala (Tragelaphus angasi); the eland (Taurotragus oryx) which hybridizes with greater kudu; gemsbok (Oryx gazella); Arabian oryx (Oryx leucoryx); and scimitar-horned oryx (Oryx dammah).

In classical taxonomy, both kudu and oryx placed in Eukaryotae; Mitochondrial; Metazoa; Chordata; Vertebrata; Eutheria; Artiodactyla; Ruminantia; Pecora; Bovoidea; Bovidae; Bovinae; Tragelaphus. This would make them more closely related to bovine than to ovine, inconsistent with prion sequence data, considered in isolation, for the oryx.

Protein Sequence Comparisons

Kudu protein sequences B and C are identical except that C has an extra octapeptide repeat. A has the usual length as B.
Sequence BA has two unusual changes in the nonapeptide, gly to glu at position 3 and gly to asp at position 6 and a further unprecedented changein the second octapeptide at position 3, gly to val . Point mutations are not seen at the amino acid level in other mammalian octapeptides.
Sequence B is normal in the repeat region except for a pro to ser at position 1 of the nonapeptide.
All three kudu sequences are novel in having gly to ala at position 21 of the signal peptide.
Oryx differs from sheep in one position in a neutral fashion, ser to thr, both commonly found here in the highly variable post-repeat domain.

Inter-kudu differences: sequence A compared to sequence B
 40        50        60       70        80
SRYPGQGSPGGNRYPPQEGGDWGQPHGGGWGQPHVGGWGQ
...............S.G..G.............G.....  

Differences relative to sheep

Sequence A:    A   E D V           T G S M E   Arch Virol
Sequence B:    A S                 T G S M E   Martin et al
Sequence C:    A S       WGQPHGGG  T G S M E   Martin et al

DNA Sequence Comparisons

The DNA sequences for A and B differ very little (9 nucleotides), as do B and C (3 nucleotides+ 24 bp repeat), or A and C (4 nucleotides + repeat) and all nucleotide differences are in the repeat region. This is odd, to see so many second and first codon changes in this region, but none in the third position in the other 85% of the DNA. Relative to sheep or oryx, nucleotide changes are scattered widely outside the repeat region and mostly in third codon position.

162       170     180    210       220         261       270       
CCTCAAGAAGGGGGTGACTGG    CAGCCTCATGTAGGTGGC    CCACATGGTGGTGGAGGG 
T....G.G........G....     ....C....G......T    ..G..............C 
 P  Q  E  G  G  D  W      Q  P  H  V  G  G      P  H  G  G  G  G

       250       260       270       280       290       300
GGAGGTGGCTGGGGTCAGCCCCATGGTGGTGGTTGGGGACAGCCACATGGTGGTGGAGGC
-----...T.......................C...........G...............
 G  G  G  W  G  Q  P  H  G  G  G  W  G  Q  P  H  G  G  G  G

162     170       180
TCTCAGGGAGGGGGTGGCTGG
C....A.A........A....
 S  Q  G  G  G  G  W

Where did the extra repeat come from in Sequence C? This can be determined at the DNA level by looking at third codon micro-heterogeneity under a maximum parsimony assumption. The result is: R1 R1 R2 R3 R4 consistent with a DNA slippage model for the genetic origin of repeats in this region. Comparison of amino acid and nucleotide sequences A, B, C in the repeat region

Sequence A	Sequence C	Sequence B
RYP	RYP	RYP
PQEGGDWGQ	SQGGGGWGQ	SQGGGGWGQ
PHGGG.WGQ	PHGGG.WGQ	PHGGG.WGQ
PHVGG.WGQ	PHGGG.WGQ	PHGGG.WGQ
PHGGG.WGQ	PHGGG.WGQ	PHGGG.WGQ
PHGGGGWGQ	PHGGG.WGQ	PHGGGGWGQ
-	PHGGGGWGQ	-
GGTHG	GGTHG	GGTHG

cgctatcca	cgctatcca	cgctatcca
cctcaagaagggggtgactggggtcag	tctcagggagggggtggctggggtcag	tctcagggagggggtggctggggtcag
ccccatggaggtggctggggccag	ccccatggaggtggctggggccag	ccccatggaggtggctggggccag
cctcatgtaggtggctggggtcag	ccccatggaggcggctggggccag	ccccatggaggtggttggggtcag
ccccatggtggtggctggggacag	cctcatggaggtggctggggtcag	ccccatggtggtggctggggacag
ccacatggtggtggagggtggggt	ccccatggtggtggttggggacag	ccgcatggtggtggaggctggggtcaag
caaggtggtacccacggt	ccacatggtggtggaggctggggt	gtggtacccacggtc
-	caaggtggtacccacggt	-

Tragelaphus streptsiceros greater kudu 257aa; 771bp Sequence A Artiodactyla; Ruminantia; Pecora; Bovoidea Bovidae; Bovinae; Tragelaphus. ACCESSION 398938; PID g398938; EMBL: locus TSPRIP,X74771; 04-OCT-1994; Martin TC et al. MVKSHIGSWILVLFVAMWSDVALCKKRPKPGGGWNTGGSRYPGQGSPGGNRYP PQEGGDWGQPHGGGWGQPHVGGWGQPHGGGWGQPHGGGGWGQGGTHGQW NKPSKPKTNMKHVAGAAAAGAVVGGLGGYMLGSAMSRPLIHFGSDYEDRYYRENMYRY PNQVYYRPVDQYSNQNNFVHDCVNITVKQHTVTTTTKGENFTETDIKMMERVVEQMCI TQYQRESEAYYQRGASVILFSSPPVILLISFLIFLIVG 1 atggtgaaaa gccacatagg cagttggatc ctggtcctct ttgtggccat gtggagtgac 61 gtggccctct gcaagaagcg accaaaacct ggaggaggat ggaacactgg ggggagccga 121 tacccgggac agggcagtcc tggaggcaac cgctatccac ctcaagaagg gggtgactgg 181 ggtcagcccc atggaggtgg ctggggccag cctcatgtag gtggctgggg tcagccccat 241 ggtggtggct ggggacagcc acatggtggt ggagggtggg gtcaaggtgg tacccacggt 301 cagtggaaca agcccagtaa gccaaaaacc aacatgaaac atgtggcagg agctgctgca 361 gcgggagcag tggtaggggg ccttggtggc tacatgctgg gaagtgccat gagcaggcct 421 cttatacatt ttggcagtga ctatgaggac cgttactatc gtgaaaacat gtaccgttac 481 cccaaccaag tgtactacag gccagtggat cagtatagta accagaacaa ctttgtgcat 541 gactgtgtca acatcacagt caagcagcac acagtcacca ccaccaccaa gggggagaac 601 ttcaccgaaa ctgacatcaa gatgatggag cgagtggtgg agcaaatgtg catcacccag 661 taccagagag aatccgaggc ttattaccaa cgaggggcaa gtgtcatcct cttctcttcc 721 cctcctgtga tcctcctcat ctctttcctc atttttctca tagtaggata g

Tragelaphus streptsiceros greater kudu 257 aa; 771bp Sequence B Artiodactyla; Ruminantia; Pecora; Bovoidea Bovidae; Bovinae; Tragelaphus. Poidinger M, Kirkwood J, Almond W in Arch Virol 131 (1-2): 193-199 (1993): not submitted MVKSHIGSWILVLFVAMWSDVALCKKRPKPGGGWNTGGSRYPGQGSPGGNRYP SQGGGGWGQPHGGGWGQPHGGGWGQPHGGGWGQPHGGGGWGQGGTHGQW NKPSKPKTNMKHVAGAAAAGAVVGGLGGYMLGSAMSRPLIHFGSDYEDRYYRENMYRY PNQVYYRPVDQYSNQNNFVHDCVNITVKQHTVTTTTKGENFTETDIKMMERVVEQMCI TQYQRESEAYYQRGASVILFSSPPVILLISFLIFLIVG 1 atgg tgaaaagcca cataggcagt tggatcctgg 35 tCctctttgt ggccatgtgg agtgacgtgg Ccctctgcaa gaagcgacca aaacctggAg 95 gaggatggaa cactgggggg agccgatacc cgggacaggg cagtcctgga ggcaaccgct 155 atccaTctca gggagggggt ggctggggtc agccccatgg aggtggctgg ggccaGccCc 215 atggaggtgg Ttggggtcag ccccatggtg gtggctgggg acagccGcat ggtggtggag 275 gctggggtca aggtggtaCc cacGgtcagt ggaacaagcc cagtaagcca aaaaccaaca 335 tgaaAcatgt ggcaggagct gctgcagcGg gagcagtggt agggggcctt ggtggctaca 395 tgctgggaag tgccatgagc aggcctctta tacattttgg caGtgactat gaggaccgtt 455 actatcgtga aaacatgtac cgttacccca accaagtgta ctacagGcca gtggatcAgt 515 atagtaacca gaacaacttt gtgcatgact gtgtcaacat cacagtcaag caGcacacag 575 tcaccaccac caccaagggg gagaacttca ccgaaactga catcaagatG atggagcgag 635 tggtggagca aatgtgcatc acccagtacc agagagaatc cGaggcttat taccaaCgAg 695 gggcaagtgt CatcctcttC tcttcccctc ctgtgatcct cctcatctct ttcctcattt 755 ttctcatagt aggatag

Tragelaphus streptsiceros greater kudu 265 aa; 795bp Sequence C Artiodactyla; Ruminantia; Pecora; Bovoidea Bovidae; Bovinae; Tragelaphus. PID g730409; embl X74759, gi: 400491; SWISSPROT: PRP2_TRAST, P40243; updated: Feb 1995; Martin TC et al. MVKSHIGSWI LVLFVAMWSD VALCKKRPKP GGGWNTGGSR YPGQGSPGGN RYPSQGGGGW GQPHGGGWGQ PHGGGWGQPH GGGWGQPHGG GWGQPHGGGG WGQGGTHGQW NKPSKPKTNM KHVAGAAAAG AVVGGLGGYM LGSAMSRPLI HFGSDYEDRY YRENMYRYPN QVYYRPVDQY SNQNNFVHDC VNITVKQHTV TTTTKGENFT ETDIKMMERV VEQMCITQYQ RESEAYYQRG ASVILFSSPP VILLISFLIF LIVG 1 atggtgaaaa gccacatagg cagttggatc ctggtcctct ttgtggccat gtggagtgac 61 gtggccctct gcaagaagcg accaaaacct ggaggaggat ggaacactgg ggggagccga 121 tacccgggac agggcagtcc tggaggcaac cgctatccat ctcagggagg gggtggctgg 181 ggtcagcccc atggaggtgg ctggggccag ccccatggag gcggctgggg ccagcctcat 241 ggaggtggct ggggtcagcc ccatggtggt ggttggggac agccacatgg tggtggaggc 301 tggggtcaag gtggtaccca cggtcagtgg aacaagccca gtaagccaaa aaccaacatg 361 aaacatgtgg caggagctgc tgcagcggga gcagtggtag ggggccttgg tggctacatg 421 ctgggaagtg ccatgagcag gcctcttata cattttggca gtgactatga ggaccgttac 481 tatcgtgaaa acatgtaccg ttaccccaac caagtgtact acaggccagt ggatcagtat 541 agtaaccaga acaactttgt gcatgactgt gtcaacatca cagtcaagca gcacacagtc 601 accaccacca ccaaggggga gaacttcacc gaaactgaca tcaagatgat ggagcgagtg 661 gtggagcaaa tgtgcatcac ccagtaccag agagaatccg aggcttatta ccaacgaggg 721 gcaagtgtca tcctcttctc ttcccctcct gtgatcctcc tcatctcttt cctcattttt 781 ctcatagtag gatag

Oryx leucoryx Arabian oryx 257 aa;771bp Artiodactyla; Ruminantia; Pecora; Bovoidea; Bovidae; Bovinae; Oryx. Poidinger M, Kirkwood J, Almond W in Arch Virol 131 (1-2): 193-199 (1993): not submitted MVKSHIGSWILVLFVAMWSDVGLCKKRPKPGGGWNTGGSRYPGQGSPGGNRYP PQGGGGWGQPHGGGWGQPHGGGWGQPHGGGWGQPHGGGGWGQGGTHSQWNKPS KPKTNMKHVAGAAAAGAVVGGLGGYMLGSAMSRPLIHFGNDYEDRYYRENMYR YPNQVYYRPVDQYSNQNNFVHDCVNITVKQHTVTTTTKGENFTETDIKIMERV VEQMCITQYQRESQAYYQRGASVILFSSPPVILLISFLIFLIVG atgg tgaaaagcca cataggcagt tggatcctgg ttctctttgt ggccatgtgg agtgacgtgg gcctctgcaa gaagcgacca aaacctggTg gaggatggaa cactgggggA agccgatacc cgggacaggg cagtcctgga ggcaaccgct atccacctca gggagggggt ggctggggtc agccccatgg aggtggctgg ggccaacctc atggaggtgg ctggggtcag ccccatggtg gtggctgggg acagccacat ggtggtggag gctggggtca aggtggtaCc cacagtcagt ggaacaagcc cagtaagcca aaaaccaaca tgaagcatgt ggcaggagct gctgcagctg gagcagtggt agggggcctt ggAggctaca tgctgggaag Cgccatgagc aggcctctta tacattttgg caatgactat gaggaccgtt actaCcgtga aaacatgtac cgttacccca accaagtgta ctacagacca gtggatcAgt atagtaacca gaacaacttt gtgcatgact gtgtcaacat cacagtcaag caacacacag tcaccaccac caccaagggg gagaacttca ccgaaactga catcaagatC atggagcgag tggtggagca aatgtgcatc acccagtacc agagagaatc ccaggcttat taccaaagAg gggcaagtgt gatcctcttC tcttcccctc ctgtgatcct cctcatctct ttcctcattt ttctcatagt aggatag

Ovis aries Sheep gene 257 aa;771bp Artiodactyla; Ruminantia; Pecora; Bovoidea Bovidae; Caprinae; Ovis. MVKSHIGSWILVLFVAMWSDVGLCKKRPKPGGGWNTGGSRYPGQ GSPGGNRYPPQGGGGWGQPHGGGWGQPHGGGWGQPHGGGWGQPHGGGGWGQGGSHSQW NKPSKPKTNMKHVAGAAAAGAVVGGLGGYMLGSAMSRPLIHFGNDYEDRYYRENMYRY PNQVYYRPVDQYSNQNNFVHDCVNITVKQHTVTTTTKGENFTETDIKIMERVVEQMCI TQYQRESQAYYQRGASVILFSSPPVILLISFLIFLIVG 747 atgg tgaaaagcca cataggcagt tggatcctgg 781 ttctctttgt ggccatgtgg agtgacgtgg gcctctgcaa gaagcgacca aaacctggcg 841 gaggatggaa cactgggggg agccgatacc cgggacaggg cagtcctgga ggcaaccgct 901 atccacctca gggagggggt ggctggggtc agccccatgg aggtggctgg ggccaacctc 961 atggaggtgg ctggggtcag ccccatggtg gtggctgggg acagccacat ggtggtggag 1021 gctggggtca aggtggtagc cacagtcagt ggaacaagcc cagtaagcca aaaaccaaca 1081 tgaagcatgt ggcaggagct gctgcagctg gagcagtggt agggggcctt ggtggctaca 1141 tgctgggaag tgccatgagc aggcctctta tacattttgg caatgactat gaggaccgtt 1201 actatcgtga aaacatgtac cgttacccca accaagtgta ctacagacca gtggatcagt 1261 atagtaacca gaacaacttt gtgcatgact gtgtcaacat cacagtcaag caacacacag 1321 tcaccaccac caccaagggg gagaacttca ccgaaactga catcaagata atggagcgag 1381 tggtggagca aatgtgcatc acccagtacc agagagaatc ccaggcttat taccaaaggg 1441 gggcaagtgt gatcctcttt tcttcccctc ctgtgatcct cctcatctct ttcctcattt 1501 ttctcatagt aggatag

Bos taurus bovine 257 aa;771bp Artiodactyla; Ruminantia; Pecora; Bovoidea Bovidae; Bovinae; Bos. MVKSHIGSWILVLFVAMWSDVGLCKKRPKPGGGWNTGGSRYPGQ GSPGGNRYPPQGGGGWGQPHGGGWGQPHGGGWGQPHGGGWGQPHGGGGWGQGGSHSQW NKPSKPKTNMKHVAGAAAAGAVVGGLGGYMLGSAMSRPLIHFGNDYEDRYYRENMHRY PNQVYYRPVDQYSNQNNFVHDCVNITVKEHTVTTTTKGENFTETDIKMMERVVEQMCI TQYQRESQAYYQRGASVILFSSPPVILLISFLIFLIVG 1 atggtgaaaa gccacatagg cagttggatc ctggttctct ttgtggccat gtggagtgac 61 gtgggcctct gcaagaagcg accaaaacct ggcggaggat ggaacactgg ggggagccga 121 tacccgggac agggcagtcc tggaggcaac cgctatccac ctcagggagg gggtggctgg 181 ggtcagcccc atggaggtgg ctggggccag cctcatggag gtggctgggg tcagccccat 241 ggtggtggct ggggacagcc acatggtggt ggaggctggg gtcaaggtgg tagccacagt 301 cagtggaaca aacccagtaa gccaaaaacc aacatgaagc atgtggcagg agctgctgca 361 gctggagcag tggtaggggg ccttggtggc tacatgctgg gaagtgccat gagcaggcct 421 cttatacatt ttggcaatga ctatgaggac cgttactatc gtgaaaacat gcaccgttac 481 cccaaccaag tgtactacag gccagtggat cagtatagta accagaacaa ctttgtgcat 541 gactgtgtca acatcacagt caaggaacac acagtcacca ccaccaccaa gggggagaac 601 ttcaccgaaa ctgacatcaa gatgatggag cgagtggtgg agcaaatgtg cattacccag 661 taccagagag aatcccaggc ttattaccaa cgaggggcaa gtgtgatcct cttctcttcc 721 cctcctgtga tcctcctcat ctctttcctc atttttctca tagtaggata g

References

Epidemiological observations on spongiform encephalopathies in captive wild animals in the British Isles

Vet Rec 135 (13): 296-303 (Sep 24 1994) 
Kirkwood JK, Cunningham AA

Since 1986, scrapie-like spongiform encephalopathy has been diagnosed in 19 captive wild animals of eight species at or from eight zoological collections in the British Isles. The affected animals have comprised members of the family Bovidae: one nyala (Tragelaphus angasi), four eland (Taurotragus oryx), and six greater kudu (Tragelaphus strepsiceros), one gemsbok (Oryx gazella), one Arabian oryx (Oryx leucoryx), and one scimitar-horned oryx (Oryx dammah), and members of the family Felidae: four cheetah (Acinonyx jubatus) and one puma (Felis concolor). In addition, three cases of a spongiform encephalopathy of unknown aetiology have been reported in ostriches (Struthio camellus) from two zoos in north west Germany. Three features suggest that some of these cases may have been caused by the agent of bovine spongiform encephalopathy (BSE). First, they have been temporally and geographically coincident with the BSE epidemic. Secondly, in all the ungulates for which details are available, it is possible that either the affected animal itself, or the herd into which it was born or moved, had been exposed to proprietary feeds containing ruminant-derived protein or other potentially contaminated material, and all the carnivores had been fed parts of cattle carcases judged unfit for human consumption. Thirdly, the pathological results of inoculating mice with a homogenate of fixed brain tissue from the nyala and from one greater kudu were similar to the results of inoculating mice with BSE brain tissue.

Spongiform encephalopathy in a herd of greater kudu: epidemiological observations.

Kirkwood JK, Cunningham AA, Wells GA, Wilesmith JW, Barnett JE
Vet Rec 133 (15): 360-364 (Oct 9 1993)

A small herd of greater kudu, derived from three individuals, has been maintained at the Zoological Society of London since 1970. Spongiform encephalopathy has been diagnosed in five out of eight of the animals born in this herd since 1987. With the possible exception of the first confirmed case, none of these is thought to have been exposed to feeds containing ruminant-derived protein. The pattern of incidence suggests that greater kudu are very susceptible to the disease and that natural lateral transmission may have occurred among them.

Spongiform encephalopathy in an arabian oryx (Oryx leucoryx) and a greater kudu

Vet Rec 127 (17): 418-420 (Oct 27 1990) 
Kirkwood JK, Wells GA, Wilesmith JW, Cunningham AA, Jackson SI

Clinical, pathological and epidemiological details of scrapie-like encephalopathies are described in an arabian oryx and a greater kudu. Clinical signs included ataxia and loss of condition with a short, progressive clinical course (22 and three days, respectively). Histopathological examination of the brains revealed spongiform encephalopathy characteristic of that observed in scrapie and bovine spongiform encephalopathy (BSE). It seems probable that these cases have a common aetiology with BSE. Scrapie-like spongiform encephalopathies have now been described in five species of exotic artiodactyls in Britain indicating a, hitherto inapparent, wider range of ruminant species as natural hosts for these diseases. See also:

Ultrastructural features of spongiform encephalopathy transmitted to mice from three species of bovidae

Acta Neuropathol (Berl) 84 (5): 559-569 (1992)
Jeffrey M, Scott JR, Williams A, Fraser H

Studies on a male eland X kudu hybrid.

J Reprod Fertil 46 (1): 13-16 (Jan 1976) 
Jorge W, Butler S, Benirschke K

An accidental mating between a male eland and a female kudu produced an animal with primarily eland phenotypic characteristics. Despite pronounced male behaviour the animal was azoospermic. Histological examination of the testis showed complete lack of germ cells. Chromosome studies with analysis of Giemsa bands showed that the parental karyotypes differed by two reciprocal translocations and one pericentric inversion, involving chromosomes 1 and 3, 5 and 11, and 9 respectively. All other chromosomes had identical banding patterns.

The unusual karyotype of the lesser kudu, Tragelaphus imberbis.

Cytogenet Cell Genet 26 (2-4): 85-92 (1980) 
Benirschke K, Ruedi D, Muller H, Kumamoto AT, Wagner KL, Downes HS

The chromosome set of the lesser kudu, Tragelaphus imberbis, consists of 38 elements in both sexes. In contrast to most other members of the bovid subfamily Tragelaphinae, both the X and the Y chromosomes are compound, having fused with identical autosomes from ancestors presumed to have higher chromosome numbers. From a comparison of the unusual sex chromosomal rearrangements that have occurred in this family, a hypothetical lineage has been derived. This family tree and the details of various banding studies in the lesser kudu are described.

Scrapie-like encephalopathy in a greater kudu (Tragelaphus strepsiceros) which had not been fed ruminant-derived protein.

Vet Rec 130 (17): 365-367 (Apr 25 1992)
Kirkwood JK, Wells GA, Cunningham AA, Jackson SI, Scott AC, Dawson M, Wilesmith JW

A 19-month-old greater kudu (Tragelaphus strepsiceros), whose dam had died 15 months earlier with spongiform encephalopathy, required euthanasia after developing severe ataxia and depression with an apparently sudden onset. No macroscopic abnormalities were detected on post mortem examination but a scrapie-like spongiform encephalomyelopathy was apparent on histopathological examination of brain and segments of spinal cord. Negative stain electron microscopy of proteinase K-treated detergent extracts of tissue from the brain stem revealed the presence of scrapie associated fibrils, and a 25 to 28 kDa band comparable with that identified as abnormal PrP (prion protein) from the brains of domestic cattle with spongiform encephalopathy was detected using rabbit antiserum raised against mouse PrP. The animal was born nine months after the statutory ban on the inclusion of ruminant-derived protein in ruminant feeds and, as no other possible sources of the disease were apparent, it appears likely that the infection was acquired from the dam.

mad cow home or moly bio area or best links