MA / African horsesickness is a disease endemic in Sub Saharan Africa affecting horses, a non-native species, which are extremely susceptible to this disease. Both the ‘dunkop’ form (with its dramatic high fever, laboured breathing, frothy nasal discharge and sudden death) and the ‘dikkop’ form (with its swollen head and eyes and bleeding in the membranes of the mouth and eyes) have been visited upon equine populations and their human owners in successive epidemics through the earliest colonial settlement until recent times. This thesis traces the development of veterinary science in South Africa and the effect it had on the changing ideas surrounding African horsesickness. It explores not only the veterinary progress in the country but also the impact of the progress on African horsesickness as other diseases received attention. The discussion traces the disease from one of the major epidemics ever encountered in the country, in the mid nineteenth century, to the beginning of the development of veterinary services in South Africa when little was known about African horsesickness. It illustrates the implications of a country's struggle with animal disease, the reasons for a lack of knowledge and the ramifications of the Onderstepoort Veterinary Institute’s interventions. This thesis shows that African horsesickness not only had an impact on the veterinary developments of the country but was also indirectly involved in the South African War, 1899-1902. It demonstrates the impact of disease during wartime while illustrating the importance of horses during such difficult times. Thus, this thesis draws on works on animal diseases and on social history to explore not only the effect African horsesickness had historically on equines, but the effects it had more broadly on southern African society. This study is intended to bring insight into the social history of the disease itself: how it was experienced by livestock owners and also how settler and indigenous efforts were turned towards combating this dramatic disease.

African horse sickness (AHS) is a non-contagious viral disease transmitted by an arthropod vector and is endemic to sub-Saharan Africa. The disease affects all equine species, but is more severe in horses and other equid species not native to Africa. Vaccination is the only demonstrated means of its prevention. The horse-owning public provides much anecdotal evidence of prophylactic strategies, such as repellents, stabling, alternate hosts, traps, paraffin, blankets, smoke or fans. The present study investigated the relationship of these strategies to the incidence of AHS, and evaluated alternate hosts, wind speed and repellents on the activity of males and females of the different Culicoides species.. Cypermethrin and citronella-containing repellents repelled the most female midges. Sheep and cattle offer an alternate blood meal to gravid and nulliparous female midges. Fans are very effective in keeping midges away from horses. Methods are summarised for the horse owner to implement in addition to vaccination to prevent AHS. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

African horse sickness virus causes a non-contagious, infectious disease of equids. It is epizootic to sub-Saharan Africa and parts of the Middle East. The epizootics caused by the virus have caused widespread devastation amongst equids worldwide. Fortunately no epizootic has lasted more than 5 years outside of sub- Saharan Africa. It is vectored by species of Culicoides midges (Diptera: Ceratopogonidae) and most importantly by the two Avarita species of C. imicola Keiffer and C. bolitinos Meiswinkel. The literature pertaining to the study and research of the virus, the disease and the vectors is reviewed. Models allowing prediction of future possible outbreaks as well as details of control strategies and findings of researchers are presented and discussed. The virus needs a long term reservoir host in which to overwinter and various theories are discussed. Control measures in South Africa are suggested so that outbreaks of the disease can be reduced. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermarizburg, 2008.

Dissertation (PhD(Agric))--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: This study was carried out to investigate whether environmental and/or genetic factors had an effect on the incidence of epistaxis related to exercise-induced pulmonary haemorrhage among racehorses in Southern Africa. A further aim was to estimate the heritability of liability to epistaxis in the Southern African Thoroughbred population. For the purpose of the environmental study, the data covering the period 1986-2001 and involving a total of778 532-race runs, were analysed. This included the following race start information: date of race (day/month/year), age, sex, breeder, trainer, distance, jockey, state of going, weight carried, centre of racing and altitude. The genetic part of the data was two-fold in nature and included firstly the analysis of all horses that suffered epistaxis whilst racing in Southern Africa from 1986 to 2001 and involving 1118 individual bleeders. The second genetic analysis included the same Southern African population plus those Southern African horses exported to Mauritius and then being recorded as bleeders in that country (1252 bleeders in total). Pedigree data covering the period 1960-1986 was used as required to calculate the incidence of bleeding amongst ancestors of the post 1986 era. Only pedigrees of horses that raced were included in this study as it was not possible to predict whether non-runners would have bled had they raced. Consequently all non-runners and also those that raced overseas in countries where bleeding occurrence was not recorded were excluded. Veterinarians employed by the Jockey Club suspended officially recorded horses that showed epistaxis as demonstrated by frank bleeding from the nostrils after racing. Oncourse endoscopy is not employed as a routine on any of the Southern African racetracks. In the environmental study epistaxis was identified in 1 287 race starts (0.165%). Epistaxis related to exercise-induced pulmonary haemorrhage was significantly (p<0.001) associated with altitude, age, race year, month and the day of racing. More horses demonstrated epistaxis at sea level than at altitude, between the months of May - October than the rest of the year, in older horses than in horses less than three-years old, after 1995 than between the years 1986 and 1995, and on Fridays and Sundays than on any other week day. No association could be established between epistaxis and breeder, trainer, distance, jockey, state of going, sex and weight carried. The heritability of liability method as described by Falconer (1989) was used to estimate the relative importance of heredity and environment. For the period investigated, the population incidence for epistaxis in Southern African horses was 2.1%. The estimation of heritability ofliability showed that first-degree relatives had a figure of 55.4%. The heritability of second- and third degree relatives were 41.3% and 30.4% respectively. The data investigated depicts horses that bled almost exclusively on race days as only a small percentage (- 5%) was reported as having bled during exercise. Accordingly, the full extent of epistaxis amongst racing Thoroughbreds in Southern Africa is difficult to gauge. Pedigree and race run data from Thoroughbreds racing in Southern Africa, covering the period 1986-2002 (63 146) horses in pedigree data-set and 778 532 race runs, were further analysed in order to study genetic and environmental factors affecting the incidence of epistaxis as associated with EIPH (exercise-induced pulmonary haemorrhage). As fixed effects for the model, variables that were tested significantly in a preliminary data analyses, were included. Various combinations of such variables namely age, weight, altitude, sex, month and going were tested. Fixed effects that were included in the fmal model were gender, going and altitude. The heritability estimates from a logit transformed analysis for epistaxis fitting both the animal and sire generalized mixed models were 0.23 and 0.40 respectively, which indicated that epistaxis as associated with EIPH in the Southern African Thoroughbred sires has a strong genetic basis. Genetic trends indicating an increase in epistaxis were also found. It is concluded that the frequency of epistaxis related to pulmonary haemorrhage is associated with altitude, winter and spring months and the horse's age. It is suggested that racing at a lower altitude may increase the probability of exercise-induced pulmonary haemorrhage. It is clear that epistaxis in the racing Thoroughbred has a strong genetic basis. It is further suggested that horses showing frank bleeding from the nostrils after racing or exercise, be suspended and not used for breeding purposes. This would result in relatively fast progress being made towards eradicating this costly scourge of the modem Thoroughbred racehorse. Affected stallions and those racing whilst being treated with furosemide, should be barred from breeding and not be considered as future sires. Estimated breeding values for epistaxis should be used as a tool for selecting against it and be considered in breeding programmes to decrease the incidence thereof. / AFRIKAANSE OPSOMMING: 'n GENETIESE ANALISE VAN DIE VOORKOMS VAN LONGBLOEDING IN DIE SUID-AFRIKAANSE RENPERD: Die doel met hierdie studie was om vas te stelof omgewings- of genetiese faktore enige invloed op die voorkoms van longbloeding in die Suid-Afrikaanse renperd het. 'n Verdere doelstelling was om die oorerflikheid op die onderliggende verspreiding van longbloeding in die Suid-Afrikaanse Volbloedpopulasie te bepaal. Vir die omgewingstudie is data wat oor die periode 1986-2001 strek en wat 'n totaal van 778 532 wedren-deelnames ingesluit het, statisties ondersoek. Die data het die volgende inligting ingesluit: datum van deelname, ouderdom, geslag, teler, afrigter, afstand van wedren, jokkie, toestand van baanoppervlakte, gewig gedra, sentrum waar deelname plaasgevind het en die hoogte bo seespieël van die sentrum. Die studie van die genetiese aspekte het eerstens 'n analise van al die perde wat longbloeding tydens 'n wedren in Suider-Afrika gedurende die jare 1986-2002 ondervind het (I118 perde), en tweedens dieselfde populasie perde, plus die Suiderlike-Afrikaanse perde wat uitgevoer is na Mauritius en bloeding daar ondervind het, (1252 perde), ingesluit. Ter aanvulling is uitgebreide stamboomdata van voorouers gedurende 1960-1986 gebruik om die voorkoms van longbloeding tydens die post 1986 tydvak te bepaal. Slegs stambome van renperde wat aktief aan renne deelgeneem het, is in die data ingesluit aangesien dit nie moontlik was om te voorspel of 'n perd wat nooit aan wedrenne deelgeneem het nie, longbloeding sou ondervind indien dit wel deelgeneem het. Dus is alle renperde wat nooit aan wedrenne deelgeneem het, asook daardie perde wat in die buiteland deelgeneem en waar longbloeding nie aangeteken word nie, uitgesluit. Alle perde wat bloeding van die neus na wedrenne getoon het, is deur veeartse in diens van die Jokkie Klub van Suid-Afrika ondersoek, as 'n bloeier aangeteken en van verdere deelname aan wedrenne geskors. Endoskopie word op geen van die Suid- Afrikaanse renbane as 'n standaard praktyk na wedrenne uitgevoer nie. Longbloeding het in 1 287 perde of gedurende 0.165% van alle wedrenne plaasgevind. Longbloeding soos geassossieer met EIPH, (exercise-induced pulmonary haemorrhage), is betekenisvol (p<0.001) met hoogte bo seespieël, ouderdom, dag van deelname, maand, en jaar verbind. Meer perde het longbloeding by seevlak in vergelyking met hoër vlakke bo seespieël ondervind, tussen die maande Mei-Oktober as die res van die jaar, in perde ouer as drie-jaar, na 1995 as tussen die jare 1986-1995, op Vrydae en Sondae as enige ander dag van die week. en meer by reuns as by merries of hingste. Geen verwantskap kon tussen bloeding en teler, afrigter, afstand, jokkie, toestand van baan, geslag en gewig gedra, gevind word nie. Die oorerflikheid op die onderliggende verspreiding vir longbloeding soos omskryf deur Falconer (1989), is gebruik om die relatiewe belangrikheid van oorerflikheid en omgewing te bepaal. Vir die periode bestudeer, was die voorkoms van longbloeding in die Suid-Afrikaanse renperd 2.1%. Die oorerflikheid van longbloeding was 55.4% vir eerste-graadse verwantes. By tweede-graadse verwantes was die ooretlikheid 41.3% en by derde-graadse verwantes 30.4%. Die data wat ondersoek is, was bykans uitsluitlik die van perde wat tydens wedrenne gebloei het en slegs 'n baie klein persentasie (~ 5%) was aangeteken as perde wat tydens oefening gebloei het. Dus is die volle omvang van longbloeding in Suider-Afrikaanse Volbloedperde moeilik om akkuraat te bepaal. Die stamboom- en wedrendata van Suid-Afrikaanse Volbloedperde is verder ontleed in 'n poging om die genetiese en omgewingsfaktore se invloed op die voorkoms van longbloeding, soos geassosieer met EIPH te bepaal. As vaste effekte vir die model is veranderlikes wat betekenisvol gevind was, ingesluit. Verskeie kombinasies van hierdie veranderlikes soos ouderdom, gewig, hoogte bo seespieël, geslag, maand en toestand van die baan is ingesluit. Die vaste effekte wat in die finale model ingesluit is, was geslag, toestand van die baan en hoogte bo seespieël. Die beraamde oorerflikheid verkry vanaf 'n "logit" getransformeerde analise vir longbloeding wat beide die diere- en vader- gemengde model gepas het, was onderskeidelik 0.23 en 0.40, wat 'n aanduidending is dat longbloeding, soos geassosieer met ElPH, 'n sterk genetiese grondslag het. Genetiese tendense het ook gedui op 'n toename in die voorkoms van longbloeding, veraloor die laaste vyf jaar van die studie. Samevattend is die bevinding dat die frekwensie van longbloeding 'n betekenisvolle verwantskap toon met hoogte bo seespieël, winter en lente maande en die perd se ouderdom. Dit word voorgestel dat renperde wat deelneem aan wedrenne by laer vlakke van hoogte bo seespieël, meer onderhewig aan longbloeding sal wees. Uit die resultate verkry is dit duidelik dat longbloeding 'n genetiese grondslag het. Dit word voorgestel dat perde wat fisiese simptome van neusbloeding na of gedurende wedrenne toon, geskors word van verdere deelname en ook nie toegelaat word om mee te teel nie. Hierdie maatreëls behoort aanleiding te gee dat relatief vinnige vordering gemaak sal word in die strewe om hierdie ongewenste sindroom in die moderne Volbloed te verminder. Aangetaste hingste, asook die wat aan wedrenne deelgeneem het terwyl hul behandeling ontvang met furosemide, moet nie toegelaat word om te teel en nie as toekomstige teelhingste oorweeg word nie. Die waarde van voorspelde teelwaardes vir longbloeding moet nie onderskat word in seleksie daarteen nie en moet in teelprogamme om die voorkoms daarvan te verminder, oorweeg word.

African horse sickness (AHS) is a viral disease with high mortality rates, vectored by the Culicoides midge and affecting members of the Equidae family. AHS is endemic to South Africa, and, as a result, affects export and international competitiveness in equine trade, and impacts significantly on the South African racehorse and performance horse industries. AHS also has devastating consequences for rural and subsistence equine ownership. The protocol developed in this dissertation has the potential to serotype and confirm the AHS virus within a few hours at significantly less cost than current methods. It will ease the financial and time constraints of studying an outbreak in real time and has the potential to solve many of the unknown factors surrounding AHS, particularly and most importantly, the role that each serotype plays in outbreaks and the form of the disease contracted by horses. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.