Describing an emerging disease: A case of thrombocytopenic syndrome of the newborn calf

Since the last 5 years, a specific hemorrhagic syndrome of unknown etiology was described in young calves. This disease has a low incidence but a very high mortality rate. No etiology has been found yet, though many labs have already gathered lots of cases around Europe. For example, more than 200 cases in 170 farms in Germany, 60 cases in 40 farms were described in Gent’s veterinary faculty in Belgium. In France and in the United Kingdom, several cases have been recorded yet, in multiple different locations. As far as we know, the disease concern young calves aging between 10 and 30 days, from different breeds. Most calves present a purpura on multiple sites on skin, gums, eye sclera and ears. Hematology indicates severe anemia, thrombocytopenia, neutropenia with or without leukopenia. Necropsy indicates multiple hemorrhages in serous membranes on every abdominal viscera. Alfort’s veterinary faculty has described acute necrotizing hepatitis on one case in France. Those calves are BVDV and BTV negative both on antigen tests.
In Liege’s veterinary faculty one live case was examined, from a modern farm with 160 calvings, and less than 5% of calf mortality per year. The farm had 3 hemorrhagic fatal cases during July 2009, of very quick evolution. From those, 2 were autopsied and diagnosed BVDV negative.
The 20 days old calf had hyperthermia in the morning, received oxytetracycline in the farm and began bleeding at noon. As many of the described cases, the calf presented mild depression with hyperthermia and tachypnoea. Skin and ear purpura, gum hematoma, melena, hematuria and hemoglobinuria were noticed. Hematology revealed a severe anemia with decreased hematocrite due to a profound thrombocytopenia (4.79*109/l). Leukocytes formula also shown neutropenia (0.10*109/l) and a monocytosis (1.32*109/l). It resulted in a mild leukopenia (3.59*109/l). We also noticed hypogammaglobulinemia (2.92 g/l and 6.8% of total protein).
This calf received an immune-suppressive treatment with a high dose of dexamethasone (0.64mg/kg), and a cover antimicrobial therapy (Enrofloxacine). A good evolution of the symptoms on day 2 was observed. Leukocyte formula had a normal answer to dexamethasone concerning the lymphocytes and neutrophils population. On day 6, blood formula was already stabilized, with increasing hematocrite from 12% on day 3 to 15%. Thrombocytes count has also increased to 58.20*109/l; leukocytes count was also back to normal with normal formula. Flow cytometric measures on the lymphocytes subpopulations indicated a subnormal Gamma-Delta and Natural Killer population, and a high number of apoptotic cells 12 hours after sampling. This syndrome can be linked to idiopathic thrombocytopenia in human newborn both regarding symptomatology and treatment answer.
Though this data helps in the understanding of this pathology, it concerns only one animal and needs to be confirmed through further experiment on live cases.