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Neospora caninum in cattle in Sweden

isolaton of the parasite and studies of its transmission

Stenlund, Susanne (2000). Neospora caninum in cattle in Sweden. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae. Veterinaria, 1401-6257 ; 85
ISBN 91-576-5940-0
[Doctoral thesis]

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Abstract

Neospora caninum is a coccidian parasite with a two-host life cycle including a canine definitive host. In cattle the parasite is an important cause worldwide of abortion, stillbirth and calves born weak. This thesis, which deals with neosporosis in Swedish cattle, is based on five separate publications. The brain of a stillborn calf, seropositive to N. caninum and born to a seropositive cow, was homogenised and cultured on Vero cells, where growth of Neospora-like tachyzoites was detected after 8 weeks. Electron microscopy, serology, immunoblot and polymerase chain reaction (PCR) revealed no dissimilarity between this new Swedish bovine isolate and previously published Neospora isolates, confirming that it was N. caninum. The isolate was designated Nc-SweB 1. In a herd of Swedish dairy cattle N. caninum antibodies were detected in 17 (29%) out of 58 animals. All seropositive cattle were descendants of two cows that were no longer alive. Evidence of congenital transmission of N. caninum and the apparent lack of other forms of transmission indicate the ability of N. caninum to be transmitted from dam to foetus for several generations. Neospora caninum antibody levels of 13 cows were monitored during two pregnancies, and of five cows during one pregnancy. The mean antibody titres rose by 1.5-2.5 dilution steps to reach a plateau 4-5 months before parturition. This pattern was consistent in both pregnancies indicating a reactivation of the parasite rather than a reinfection at mid- gestation. Four seronegative newborn calves were given cell culture-derived tachyzoites of N. caninum with their first feed of colostrum. Two calves fed by feeding bottle developed a lasting antibody response while the two calves dosed via stomach tubes remained seronegative throughout the study. This suggests that an oral route of N. caninum infection is possible in newborn calves. A N. caninum-infected herd of 110 Swedish dairy cattle was studied over 5 years to monitor the transmission within the herd and the abortion rate. During the study the proportion of seropositive animals increased from 63% to 87%. A large part of this increase was attributed to vertical transmission, but 16 animals sero-converted apparently due to an additional horizontal route of infection, possibly including infective stages of the parasite spread by a definitive host. The abortion rate was more than twice as high as that of the average Swedish herd. An increase in abortion rate was the main detectable effect in this herd where a combination of vertical and horizontal transmission had led to N. caninum infection in almost all animals. In this series of investigations the presence of N. caninum in Sweden is confirmed and it is shown how the parasite may be transmitted within herds. Processes in infected cows are demonstrated, and the potential clinical importance of N. caninum in Swedish dairy herds is illumin

Authors/Creators:Stenlund, Susanne
Title:Neospora caninum in cattle in Sweden
Subtitle:isolaton of the parasite and studies of its transmission
Year of publishing :January 2000
Volume:85
Number of Pages:40
Papers/manuscripts:
NumberReferences
ALLI. Stenlund S, Björkman C, Holmdahl OJM, Kindahl H, Uggla A. Characterization of a Swedish bovine isolate of Neospora caninum. Parasitology Research 1997, 83, 214-219. II. Björkman C, Johansson 0, Stenlund S, Holmdahl OJM, Uggla A. Neospora species infection in a herd of dairy cattle. Journal of the American Veterinary Medical Association 1996, 208, 1441-1444. III. Stenlund S, Kindahl H, Magnusson U, Uggla A, Björkman C. Serum antibody profile and reproductive performance during two consecutive pregnancies of cows naturally infected with Neospora caninum. Veterinary Parasitology 1999, 85,227-234. IV. Uggla A, Stenlund S, Holmdahl OJM, Jakubek E-B, Thebo P, Kindahl H, Bjorkman C. Oral Neospora caninum inoculation of neonatal calves. International Journal for Parasitology 1998,28, 1467-1472. V. Stenlund S, Kindahl H, Uggla A, Björkman C. A long-term study of Neospora caninum infection in a Swedish dairy herd. (Manuscript
Place of Publication:Uppsala
ISBN for printed version:91-576-5940-0
ISSN:1401-6257
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:L Animal production > L73 Animal diseases
Subjects:Not in use, please see Agris categories
Agrovoc terms:neospora caninum, parasitoses, animal diseases, cattle, epidemiology, antibodies, diagnosis, sweden
Keywords:cattle, protozoa, Neospora caninurn, abortion, isolation of organism, experimental infection, transmission.
ID Code:15
Department:?? 7024 ??
Deposited By: Staff Epsilon
Deposited On:25 Apr 2002 00:00
Metadata Last Modified:02 Dec 2014 10:01

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