Bone marrow depletion with haemorrhagic diathesis in calves in Germany: characterization of the disease and preliminary investigations on its aetiology.
Since 2007 a new fatal haemorrhagic diathesis in calves has been observed in all areas of Germany. Analysis of 56 cases submitted for necropsy allowed its characterization. Calves fell ill within the first month of life independent of breed and sex. Only single or a few animals per herd were affected. Petechial and ecchymotic haemorrhages in many organs and tissues, particularly in skin, subcutis and gastrointestinal tract, were major findings in all animals. Microscopically a severe depletion of bone marrow cells was always observed. Lymphocytic depletion (43%) and inflammatory lesions (46%) were less frequently observed. Blood analysis of five animals indicated an aplastic pancytopenia. The resulting thrombocytopenia is regarded as major pathomechanism of this Haemorrhagic Disease Syndrome (HDS). Pedigree analysis gave no indication of hereditary disease. Tests for specific toxins such as S-(1,2-Dichlorovinyl)-L-cysteine (DCVC), furazolidone, or mycotoxins resulting in bone marrow depletion were negative. Bacterial infections, Bovine Viral Diarrhoea Virus, and Bluetongue Virus were ruled out as cause of the disease. HDS shares similarities with a circoviral infection in chickens (chicken infectious anaemia). A broad-spectrum PCR allowed detection of circoviral DNA in 5 of 25 HDS cases and in 1 of 8 non-HDS cases submitted for necropsy. Sequencing of the whole viral genome revealed a high similarity (up to 99%) with Porcine Circovirus type 2b. Single bone marrow cells stained weakly positive for PCV2 antigen by immunohistochemistry in 1 of 8 tested HDS animals. This is the first report of circovirus detection in cattle in Germany. The exact cause of HDS still remains unknown. A multifactorial aetiology involving infection, poisoning, immunopathy, or a genetic predisposition is conceivable. Additional research is necessary to clarify the pathogenesis and the potential role of PCV2 in HDS.
Bavarian Animal Health Service, Poing, Germany. eva.kappe@tgd-bayern.de
Eva C
EC
Kappe
Mohammad Yahya
MY
Halami
Benjamin
B
Schade
Michaela
M
Alex
Doris
D
Hoffmann
Armin
A
Gangl
Karsten
K
Meyer
Wolfgang
W
Dekant
Bernd-Andreas
BA
Schwarz
Reimar
R
Johne
Johannes
J
Buitkamp
Jens
J
Böttcher
Hermann
H
Müller
D000818:Animals; D001344:Autopsy / Q000662:veterinary; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000453:epidemiology* / Q000276:immunology / Q000473:pathology; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology*; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D030242:Diarrhea Virus 2, Bovine Viral / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D001908:Diarrhea Viruses, Bovine Viral / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D005858:Germany / Q000453:epidemiology; D006470:Hemorrhage / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary; D008297:Male; D010198:Pancytopenia / Q000453:epidemiology / Q000662:veterinary; D010375:Pedigree; D010802:Phylogeny; D016133:Polymerase Chain Reaction
D004279:DNA, Viral