Impact of field vaccination with a Theileria annulata schizont cell culture vaccine on the epidemiology of tropical theileriosis

Citation
S. Singh et al., Impact of field vaccination with a Theileria annulata schizont cell culture vaccine on the epidemiology of tropical theileriosis, VET PARASIT, 101(2), 2001, pp. 91-100
Citations number
29
Categorie Soggetti
Veterinary Medicine/Animal Health
Journal title
VETERINARY PARASITOLOGY
ISSN journal
03044017 → ACNP
Volume
101
Issue
2
Year of publication
2001
Pages
91 - 100
Database
ISI
SICI code
0304-4017(20011105)101:2<91:IOFVWA>2.0.ZU;2-R
Abstract
Tropical theileriosis, caused by Theileria annulata, is an important tick-b orne disease of cattle. A cell culture attenuated vaccine has been develope d in our laboratory by long-term in vitro propagation of the schizont stage of the parasite. A longitudinal study was conducted at selected farms hous ing indigenous, cross-bred and exotic animals to investigate the effect of vaccination on the epidemiology of the disease. A total of 120 animals in 4 age groups were vaccinated with the vaccine before the onset of disease se ason. An equal number of age-matched animals were kept as controls at the s ame sites. Animals were monitored for 14 months at monthly intervals. The 9 7.5% vaccinated animals showed a rise in antibody titres 1 month post-vacci nation, as determined by single dilution ELISA. The 78.3% of non-vaccinated animals became sero-positive over the period of observation. Mean antibody titres were significantly higher in vaccinated than non-vaccinated animals . Cross-bred animals showed higher antibody titres followed by exotic and i ndigenous animals in both the vaccinated and non-vaccinated groups. However , the antibody titres in animals of different ages were similar. The 36.7% vaccinated and 64.2% non-vaccinated animals became carriers (<0.5% piroplas ms in erythrocytes) during the observation period. Clinical cases of theile riosis were recorded only in the non-vaccinated group suggesting that vacci nated animals were sufficiently immune to withstand field tick challenge fo r at least 14 months. (C) 2001 Elsevier Science B.V. All rights reserved.