Respiratory pathogens in thoroughbred foals up to one year of age on a stud farm in South Africa

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dc.contributor.advisor Coetzer, Jacobus A.W. en
dc.contributor.postgraduate Picard, J.A. en
dc.date.accessioned 2013-09-06T13:51:11Z
dc.date.available 2006-02-27 en
dc.date.available 2013-09-06T13:51:11Z
dc.date.created 2005-07-24 en
dc.date.issued 2007-02-27 en
dc.date.submitted 2006-02-27 en
dc.description Dissertation (MSc (Veterinary Science))--University of Pretoria, 2007. en
dc.description.abstract The project was undertaken to monitor a group of 30 foals on a farm both clinically and microbiologically from birth until one year of age, to determine the aetiology of upper respiratory tract infections and to establish immune profiles of some of the known respiratory viral pathogens. One to two months prior to the birth of their foals, blood for serology was collected from the mares. The same specimens were collected from the foals just after birth, prior to suckling and a day after suckling. Thereafter the foals were examined monthly for the presence of respiratory disease and specimens taken. The following specimens were collected from each foal: three nasopharyngeal swabs, (one for virus isolation, one for bacteria and fungus isolation, and one for mycoplasma isolation) and blood that was allowed to clot. Blood was collected in heparin from sick foals with elevated rectal temperatures. Virus isolation was done on roller tube cultures of equine embryonic lung (EEL), Vero cells and rabbit kidney 13 (RK13) cells. The bacteria (including mycoplasmas) and fungi were cultured from the swabs and identified using a variety of traditional methods. The serum neutralization test (SNT) was used to detect antibodies to equid herpesvirus 1 (EHV-1), equid herpesvirus 4 (EHV-4), equine rhinovirus 1 (ERV-1), equine rhinovirus 2 (ERV-2) and equine adenovirus 1 (EAdV-1). The complement fixation test (CFT) was used to detect antibodies to EHV-1 and EHV-4 and the haemagglutination inhibition test (HIT) antibodies to equine influenzavirus (EIV). Only EHV-4 was cultured from the nasopharyngeal swabs of nine foals when they were 5 to 6 months of age and from one foal two months later. A wide variety of bacteria and fungi were cultured and it was established that coagulase-negative staphylococci, viridans streptococci, Moraxella spp. and Flavobacterium spp. predominated in most of the samples. Several potential bacterial pathogens were isolated but the most common were Streptococcus equi subsp. zooepidemicus, Actinobacillus equuland Staphylococcus aureus. Colostrum-derived antibodies were detected for all the viruses in all but two of the foals. It was found that the foals had similar or slightly higher titres than their mothers. The levels declined in direct proportion to what they initially were and were depleted by the time the foals were 2 to 7 months of age. Antibodies to natural infection was detected to EHV-4, ERV-2 and EAdV-1. A rise in antibody titres occurred when the foals were 5 to 6 months of age, two months later and when they were one year of age. Antibodies resulting from immunization was detected to EHV-1, EHV-4 and EIV. It was established that the most important virus causing upper respiratory tract disease of the foals from 5 to 12 months of age was EHV-1 with EAdV-1 playing a minor role. These viruses caused repeated bouts of infection with a two to five months interval. Streptococcus equi subsp. zooepidemicus was considered to be the most important secondary pathogen. Prior to this period most of the foals were healthy with only a few suffering from upper respiratory disease. The aetiology was not determined in these cases, but based on the bacteriology results, it was suspected that some of them were suffering from bacterial infections. en
dc.description.availability unrestricted en
dc.description.department Veterinary Tropical Diseases en
dc.identifier.citation Picard, J 2005, Respiratory pathogens in thoroughbred foals up to one year of age on a stud farm in South Africa, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/22867 > en
dc.identifier.upetdurl http://upetd.up.ac.za/thesis/available/etd-02272006-095908/ en
dc.identifier.uri http://hdl.handle.net/2263/22867
dc.language.iso en
dc.publisher University of Pretoria en_ZA
dc.rights © 2005, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. en
dc.subject Infectious respiratory tract disease en
dc.subject Foals en
dc.subject Equid herpesvirus 4 en
dc.subject Equine adenovirus en
dc.subject Equine rhinovirus 1 en
dc.subject Equine rhinovirus 2 en
dc.subject Equine influenzavirus en
dc.subject South africa en
dc.subject Equid herpesvirus 1 en
dc.subject UCTD en_US
dc.title Respiratory pathogens in thoroughbred foals up to one year of age on a stud farm in South Africa en
dc.type Dissertation en


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