Made available in DSpace on 2014-06-11T19:24:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-06-26Bitstream added on 2014-06-13T20:28:07Z : No. of bitstreams: 1 negrao_cb_me_botfmvz.pdf: 175176 bytes, checksum: 10263dccca0cbc5083495e568e951d3b (MD5) / Universidade Estadual Paulista (UNESP) / Foram testadas 404 amostras de soro de bubalinos (Bubalus bubalis) para se verificar a ocorrência de anticorpos anti-Neospora caninum em animais oriundos de rebanhos de cinco municípios da região oeste do Estado de São Paulo, Brasil. A técnica empregada foi a reação de imunofluorescência indireta (RIFI), na diluição inicial de 1:100. Foram observados anticorpos anti-Neospora caninum em 38,1% (154/404) dos animais testados, com freqüência variando de 100 a 12800. Constatou-se diferença entre municípios (P>0,05) com variação de 16,2% a 61,4 % de animais sororeagentes. A faixa etária dos soro positivos apresentou-se significativa no município de Lucélia, sendo os animais com idade superior a cinco anos mais freqüentemente infectados (P<0,05). Esses resultados alertam para a presença da enfermidade em bubalinos na referida região, cuja ocorrência de anticorpos supera as encontradas em bovinos expondo-os, dessa forma, com intensidade ao N. caninum / Serum samples from 404 water buffaloes (Bubalus bubalis) were tested to verify occurence of anti - Neospora caninum antibodies from the west of São Paulo State, Brazil.The technique used was indirect fluorescence antibody test (IFAT), in dilutions 1:100. It was observed anti-Neospora caninum antibodies in 38,1% (154/404) about tested animals, with frequency variating 100 - 12800. Observed a significant diference between cities (P>0,05) with minimum variation of 16,2% and maximum of 61,4%. Age influenced in Lucélia, the animals with more five years old were more infected (P<0,05). This results alarm for the infection in water buffaloes from this region because the ocurrence antibodies is bigger than cattle, expose with a high level N. caninum intensity

Made available in DSpace on 2015-03-26T13:46:47Z (GMT). No. of bitstreams: 1 texto completo.pdf: 644915 bytes, checksum: d059fb831fbd9168fde56d0f1948a13a (MD5) Previous issue date: 2005-05-25 / During the past ten years, the protozoan Neospora caninum has been described and associated as an ethyological agent of infected abortions in cattle. This disease in dogs also has an abortive character, but since dogs are definitive hosts, they have relevant importance in the life cycle of this parasite, acting as a source of the disease. Other diseases such as leptospirosis and brucelosis are also disseminated in Brazil and are associated to reproductive disturbances. The objective of this study was to evaluate the presence of infection for N. caninum in cattle and dogs of rural properties in two municipalities, Viçosa and Mercês, located in the macro-region of Zona da Mata in the state of Minas Gerais, as well as to analyze the existing risk factors for the infection. Serum samples of female cattle and dogs were collected for research of anti-N. caninum antibodies, using the indirect immunofluorescence technique; Brucella abortus selective test (Buffered Acidified Antigen - BAA) and corroborative tests (2-ME and SAT) and Leptospira sp., Microscopic Agglutination Technique (MAT) without and with sera dilution. The bovine sera were tested for the three pathogenic bioagents and the canine sera for N. caninum and Leptospira sp. In addition, information was collected by applying a structured questionnaire on type of exploration, production system and reproductive problem history in cattle and habits, type of food, demographic characteristics in dogs. The prevalence of positive properties was of 54.3% and 18.5% for N. caninum in cattle and dogs, respectively; 15.2% for Brucella abortus and 6.5% for Leptospira sp. in cattle and 7.4% for Leptospira sp.in dogs. The prevalence of positive animals presented lower results: 23.3% of N. caninum in cattle and dogs, respectively; 15.2% for Brucella abortus and 6.5% for Leptospira sp. in cattle and 7.4% for Leptospira. However, it should be emphasized that the prevalence for N. caninum in cattle was significantly higher, compared to Brucella abortus (p < 0.01) and Leptospira sp. (p < 0.01). Positive properties for bovine neosporosis were associated to the presence of reproductive disturbances in the animals (p < 0.01), when the analysis considered the type of disturbance, abortion (OR = 5.2; IC 95% = 1.32-20.54) and prenatal mortality (OR = 6.0; IC 95% = 1.22 - 29.95) presented significant association. The occurrence of positive serology for N. caninum in cattle was associated to the presence of positive dogs in the property (p<0.01); however, reproductive problem in cattle was not associated with canine neosporosis (p = 0.1046). Significant association was also verified between bovine osteoporosis and type of exploration, serum positive cattle having, approximately, three times more chance (OR = 2.82 and IC 95% = 1.05 - 9.52) of belonging to a milk production system rather than mixed. The characterization of canine neosporosis did not show significant association with the variables sex (p = 0.55), age (p = 0.34), animal habit (p = 0.03; OR = 0.00; IC 95% = 0.0-1.06) and type of food (p = 0.11). The results suggest that sanitation in neosporosis has become of utmost importance in bovine herds, especially when reproductive problems resulting from the infection are considered. Therefore, it becomes evident the need for animal health authorities and institutions to fight this disease. / Durante os últimos dez anos o protozoário Neospora caninum tem sido descrito e associado como agente etiológico de abortamentos infecciosos em bovinos. Esta doença em cães também tem caráter abortivo, mas como os caninos são hospedeiros definitivos, possuem relevante importância no ciclo de vida deste parasita, funcionando como reservatório da doença. Outras doenças como a leptospirose e a brucelose também são disseminadas em nosso país e também estão associadas a transtornos reprodutivos. O objetivo deste estudo foi avaliar a presença de infecção para N. caninum em bovinos e cães existentes em propriedades rurais de dois municípios, Viçosa e Mercês, pertencentes à Macrorregião Zona da Mata do Estado de Minas Gerais, bem como analisar a existência de fatores de risco para a infecção. Foram coletadas amostras de soro de bovinos fêmeas e cães para pesquisa de anticorpos anti-N. caninum, pela técnica de imunofluorescência indireta; Brucella abortus prova seletiva (Antígeno Acidificado Tamponado - AAT) e provas confirmatórias (2-ME e SAT) e Leptospira sp., Técnica de Aglutinação Microscópica (MAT) sem e com diluição dos soros. Os soros bovinos foram testados para os três bio-agentes patogênicos e os de cães para N. caninum e Leptospira sp. Adicionalmente, foram coletadas informações, utilizando-se questionário estruturado, relativas ao tipo de exploração, sistema de produção e histórico de problemas reprodutivos em bovinos e hábitos, tipo de alimentação, características demográficas dos cães. As prevalências de propriedades positivas foram de 54,3% e 18,5% para N. caninum em bovinos e cães, respectivamente; 15,2% para Brucella abortus e 6,5% para Leptospira sp. em bovinos e 7,4% para Leptospira sp. em cães. As prevalências de animais positivos apresentaram resultados menores: 23,3% de N. caninum em bovinos e cães, respectivamente; 15,2% para Brucella abortus e 6,5% para Leptospira sp. em bovinos e 7,4% para Leptospira, entretanto, é de se destacar que, para os bovinos, a prevalência para N. caninum, significativamente superior quando comparada a Brucella abortus (p < 0,01) e Leptospira sp. (p < 0,01). Propriedades positivas para neosporose bovina estiveram associadas à presença de distúrbios reprodutivos nos animais (p < 0,01), quando a análise considerou o tipo de distúrbio, abortamento (OR = 5,2; IC 95% = 1,32-20,54) e mortalidade perinatal (OR = 6,0; IC95% = 1,22 - 29,95) apresentaram associação significativa. A ocorrência de sorologia positiva para N. caninum em bovinos esteve associada à presença de cães positivos na propriedade (p < 0,01), entretanto, problema reprodutivo em bovinos não esteve associado à neosporose canina (p = 0,1046). Associação significativa também foi verificada entre a neosporose bovina e o tipo de exploração, sendo que os bovinos soropositivos tiveram, aproximadamente, três vezes mais chance (OR = 2,82 e IC 95% = 1,05 - 9,52) de pertencerem a sistema de produção tipo leite do que tipo misto. A caracterização da neosporose canina não revelou associação significativa com as variáveis sexo (p = 0,55), idade (p = 0,34), hábito do animal (p = 0,03; OR = 0,00; IC 95% = 0,0-1,06) e tipo de alimentação (p = 0,11). Os resultados sugerem o significado sanitário que a neosporose vem assumindo em rebanhos bovinos, notadamente quando se considera a ocorrência de problemas reprodutivos decorrentes da infecção. Nesse sentido, evidencia-se a atenção necessária das autoridades e instituições de saúde animal, no combate a esta enfermidade.

Orientador: Izidoro Francisco Sartor / Banca: Simone Biagio Chiacchio / Banca: Daniel Moura de Aguiar / Resumo: Foram testadas 404 amostras de soro de bubalinos (Bubalus bubalis) para se verificar a ocorrência de anticorpos anti-Neospora caninum em animais oriundos de rebanhos de cinco municípios da região oeste do Estado de São Paulo, Brasil. A técnica empregada foi a reação de imunofluorescência indireta (RIFI), na diluição inicial de 1:100. Foram observados anticorpos anti-Neospora caninum em 38,1% (154/404) dos animais testados, com freqüência variando de 100 a 12800. Constatou-se diferença entre municípios (P>0,05) com variação de 16,2% a 61,4 % de animais sororeagentes. A faixa etária dos soro positivos apresentou-se significativa no município de Lucélia, sendo os animais com idade superior a cinco anos mais freqüentemente infectados (P<0,05). Esses resultados alertam para a presença da enfermidade em bubalinos na referida região, cuja ocorrência de anticorpos supera as encontradas em bovinos expondo-os, dessa forma, com intensidade ao N. caninum / Abstract: Serum samples from 404 water buffaloes (Bubalus bubalis) were tested to verify occurence of anti - Neospora caninum antibodies from the west of São Paulo State, Brazil.The technique used was indirect fluorescence antibody test (IFAT), in dilutions 1:100. It was observed anti-Neospora caninum antibodies in 38,1% (154/404) about tested animals, with frequency variating 100 - 12800. Observed a significant diference between cities (P>0,05) with minimum variation of 16,2% and maximum of 61,4%. Age influenced in Lucélia, the animals with more five years old were more infected (P<0,05). This results alarm for the infection in water buffaloes from this region because the ocurrence antibodies is bigger than cattle, expose with a high level N. caninum intensity / Mestre

Um total de 237 fetos bovinos abortados foram enviados ao Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul entre junho de 1999 e maio de 2004. Tecidos destes fetos foram analisados através da histologia e imunoistoquímica (IHQ) anti-Neospora caninum. Destes, 72 apresentaram lesões histológicas sugestivas de infecção por protozoário, caraterizadas pela presença de miosite não-supurativa, miocardite não-supurativa, pneumonia intersticial mononuclear associada a focos de necrose e encefalite necrosante não-supurativa multifocal. O cérebro apresentava consistência líquida ou semi-líquida em 61,1% dos fetos, dificultando a obtenção de tecido para a análise histológica e IHQ. A IHQ revelou a presença de taquizoítos e raros cistos de N. caninum no cérebro de 33/47 (70,2%) dos fetos que apresentam lesões histológicas sugestivas de infecção por protozoário. No modelo final da análise multivariada, três variáveis estiveram associadas significativamente com resultado positivo na IHQ nos fetos abortados: consistência do cérebro (P=0,031), lesão no cérebro (P=0,028) e idade (P=0,189). As chances de um resultado positivo na IHQ de N. caninum foram 4,35 vezes maiores (OR=4,35; 95% CI:1,1320-2,8116) quando o feto apresentava cérebro com consistência considerada normal e 4,94 vezes maiores (OR=4,94; 95%CI: 0,1646-3,0313) na presença de lesão sugestiva de infecção por protozoário caracterizada por encefalite de intensidade variada. A probabilidade de resultado positivo na IHQ foi inversamente proporcional à idade fetal, cada mês adicional de gestação diminuíram as chances de um feto apresentar resultado positivo na imunoistoquímica por 0,41 (OR=0,41, 95%CI: 1,5982- 0,1436).

<p>Neospora caninum је интрацелуларна парaзитска кокцидија, која припада колу<br />Apicomplexa, фамилији Sarcocystidae, a oдгoвoрна je зa aбoртусe код крава ширoм свeтa.<br />Зоонотски карактер ове протозое за сада није доказан. Ипак, имунокомпромитованим особама<br />препоручује се избегавање контакта са познатим изворима N. caninum<br />Један од проблема у говедарству, су велики економски губици због неоспорозе у<br />стадима високо продуктивних плоткиња услед абортуса. Проценат абортуса се креће oд 0,4-<br />10,6% мада ове вредности могу бити и знатно више ако су инфективни агенси присутни у<br />стадима. Пошто болест пролази у већини случајева без клиничких симптома, абортуси у првој<br />трећини гравидитета могу бити непримећени тако да је губитке врло често тешко и<br />документовати.<br />Плод код заражене јединке може бити ресорбован код раног гравидитета, аутолизован<br />или мумифициран у каснијем стадијуму гравидитета или пак мртворођен. Међутим,<br />забележени су и случајеви живо рођених телади са клиничким симптомима болести или рођени<br />без клиничких симптома али позитивном серолошком реакцијом. Поред високе стопе абортуса<br />на фармама код животиња оболелих од неоспорозе који представљају директну штету,<br />економски губици се огледају и у смањеној концепцији. Нису занемарљиви ни индиректни<br />трошкови везани за ветеринарске услуге у првом реду у успостављању дијагнозе која је тешка<br />и скупа. Вишекратним вештачким осемењавањем се повећава индекс осемењавања, а због<br />смањене концепције продужава се и сервис период, смањује производња млека. Заражена стада<br />прати повећан број превремених тељења, као и рађање авиталне телади те смањени прираст<br />јунади у тову . Годишње серолошко тестирање би могло бити од користи за стратегију<br />контроле серопозитивности на N. caninum.<br />Циљ овог истраживања био је да се утврди серопреваленца Neospora caninum код крава<br />на територији Војводине. Истаживање је обухватило 376 млечних крава, старости преко 24<br />месеца, различитих раса, подељених у три групе:<br />прву групу обухватале су краве са репродуктивним поремећајима,<br />другу групу чиниле су краве без репродуктивних поремећаја,<br />трећу групу краве чија је репродуктивна историја непозната.<br />На основу добијених резултата може се закључити да је неоспооза код крава доказана<br />на целој територији АП Војводине. Укупна преваленца износи 15,4%. Код крава са побачајима<br />и другим репродуктивним поремећајима серопреваленца износи 12,8%, а код крава без<br />репродуктивних поремећаја она износи 18,8%. У раду није доказана статистички значајна<br />разлика у серопреваленци између крава са и без репродуктивних поремећаја.<br />Серопреваленца на малим приватним газдинствима износи 20,2% и статистички је<br />значајно већа у односу на велике комерцијалне фарме где износи 6,2%.<br />Из добијених резултата може се закључити да је једини доказани фактор ризика за<br />појаву неоспорозе код говеда у Војводини узгој на малим приватним газдинствима, што се<br />може објаснити слабом применом зоохигијенских мера, односно слободним држањем и<br />присуством паса на фарми.</p> / <p>Neospora caninum je intracelularna parazitska kokcidija, koja pripada kolu<br />Apicomplexa, familiji Sarcocystidae, a odgovorna je za abortuse kod krava širom sveta.<br />Zoonotski karakter ove protozoe za sada nije dokazan. Ipak, imunokompromitovanim osobama<br />preporučuje se izbegavanje kontakta sa poznatim izvorima N. caninum<br />Jedan od problema u govedarstvu, su veliki ekonomski gubici zbog neosporoze u<br />stadima visoko produktivnih plotkinja usled abortusa. Procenat abortusa se kreće od 0,4-<br />10,6% mada ove vrednosti mogu biti i znatno više ako su infektivni agensi prisutni u<br />stadima. Pošto bolest prolazi u većini slučajeva bez kliničkih simptoma, abortusi u prvoj<br />trećini graviditeta mogu biti neprimećeni tako da je gubitke vrlo često teško i<br />dokumentovati.<br />Plod kod zaražene jedinke može biti resorbovan kod ranog graviditeta, autolizovan<br />ili mumificiran u kasnijem stadijumu graviditeta ili pak mrtvorođen. Međutim,<br />zabeleženi su i slučajevi živo rođenih teladi sa kliničkim simptomima bolesti ili rođeni<br />bez kliničkih simptoma ali pozitivnom serološkom reakcijom. Pored visoke stope abortusa<br />na farmama kod životinja obolelih od neosporoze koji predstavljaju direktnu štetu,<br />ekonomski gubici se ogledaju i u smanjenoj koncepciji. Nisu zanemarljivi ni indirektni<br />troškovi vezani za veterinarske usluge u prvom redu u uspostavljanju dijagnoze koja je teška<br />i skupa. Višekratnim veštačkim osemenjavanjem se povećava indeks osemenjavanja, a zbog<br />smanjene koncepcije produžava se i servis period, smanjuje proizvodnja mleka. Zaražena stada<br />prati povećan broj prevremenih teljenja, kao i rađanje avitalne teladi te smanjeni prirast<br />junadi u tovu . Godišnje serološko testiranje bi moglo biti od koristi za strategiju<br />kontrole seropozitivnosti na N. caninum.<br />Cilj ovog istraživanja bio je da se utvrdi seroprevalenca Neospora caninum kod krava<br />na teritoriji Vojvodine. Istaživanje je obuhvatilo 376 mlečnih krava, starosti preko 24<br />meseca, različitih rasa, podeljenih u tri grupe:<br />prvu grupu obuhvatale su krave sa reproduktivnim poremećajima,<br />drugu grupu činile su krave bez reproduktivnih poremećaja,<br />treću grupu krave čija je reproduktivna istorija nepoznata.<br />Na osnovu dobijenih rezultata može se zaključiti da je neospooza kod krava dokazana<br />na celoj teritoriji AP Vojvodine. Ukupna prevalenca iznosi 15,4%. Kod krava sa pobačajima<br />i drugim reproduktivnim poremećajima seroprevalenca iznosi 12,8%, a kod krava bez<br />reproduktivnih poremećaja ona iznosi 18,8%. U radu nije dokazana statistički značajna<br />razlika u seroprevalenci između krava sa i bez reproduktivnih poremećaja.<br />Seroprevalenca na malim privatnim gazdinstvima iznosi 20,2% i statistički je<br />značajno veća u odnosu na velike komercijalne farme gde iznosi 6,2%.<br />Iz dobijenih rezultata može se zaključiti da je jedini dokazani faktor rizika za<br />pojavu neosporoze kod goveda u Vojvodini uzgoj na malim privatnim gazdinstvima, što se<br />može objasniti slabom primenom zoohigijenskih mera, odnosno slobodnim držanjem i<br />prisustvom pasa na farmi.</p> / <p>Sarcocystidae, responsible for abortion in cattle worldwide. Although zoonotic nature<br />of this protozoa has not been proven, it is generally recommended that immunocompromised<br />persons should avoid contact with the known sources of N. caninum.<br />One of the problems that affect cattle breeding industry are great economic losses due<br />to neosporosis-related abortions in herds of highly productive cows. The percentage of<br />abortions ranges from 0.4% to 10.6%, although it may reach considerably higher values when<br />the infectious agent is present in flocks. Since the disease is asymptomatic in the majority of<br />cases, abortions in the first trimester of pregnancy may remain undetected so that the losses<br />are often difficult to document.<br />Depending on the gestational age of the calf, the outcome of infection may vary from<br />the foetal resorption in early pregnancies, autolysis and mummification in the later course of<br />the gestation, or the occurrence of stillbirths. However, cases of birth of both clinically<br />diseased and asymptomatic, but seropositive newborns, from the infected mothers, have been<br />recorded. In addition to the direct damage reflected in the high rate of abortions, affected<br />farms also suffer significant economic losses due to decreased conception rates in infected<br />cows. Also, indirect costs of veterinary services, especially those regarding expensive and<br />toilsome diagnostic procedures, are not negligible. Finally, repeated artificial insemination<br />increases insemination index and decreased conception rate results in prolonged service<br />period and reduced milk production. Infected herd exhibits increased number of early calving<br />as well as birth of non-vital calves and reduced growth in beef cattle. Serological testing,<br />conducted on yearly basis, could contribute to the development of a control strategy of<br />seropositivity of the cattle to N. caninum.<br />Aim of this research was to determine seroprevalence of N. caninum in cows from the<br />territory of Vojvodina. The study included 376 dairy cows over 24 months of age, of different<br />breeds and divided into three groups, according to their medical history:<br /> The first group consisted of cows with reproductive disorders<br /> The second group consisted of cows without evident reproductive disorders<br /> The third group consisted of cows with unknown medical history<br />Based on these results it can be concluded that neosporosis in cows was demonstrated<br />throughout the territory of the Vojvodina province, with overall prevalence of 15.4%. In cows<br />with abortions and other reproductive disorders seroprevalence was 12.8% and in cows<br />without reproductive disorders it was 18.8%. No statistically significant difference in<br />seroprevalences between cows with and without reproductive disorders was observed.<br />In small private holdings, seroprevalence reached 20.2% which was significantly<br />higher compared to the 6.2% detected on large commercial farms.<br />According to these results, the only proved risk factor for acquisition of neosporosis<br />in cattle in Vojvodina is cattle being bred on private smallholdings, which could probably be<br />explained by poor zoohygienic measures, free-range to semi-confined production systems<br />and the presence of dogs, all of which are often associated with this type of farms.</p>

Despite Neospora caninum being recognised as a major cause of bovine abortion, its pathogenesis is only partially understood. Evidence of immune mediated placental pathology has been reported as being responsible for compromising pregnancy probably due to an exacerbated Th1 immune response at the maternal-foetal interface. Different clinical outcomes are known to follow experimental infections at different stages of gestation, with foetal death being the most common finding during early gestation infections, and the birth of live congenitally infected calves following infection in mid or late gestation. The aim of the current study was to characterise the placental cellular immune responses and cytokine expression following experimental Neospora infection during pregnancy. Placentomes were collected from cattle experimentally inoculated with the tachyzoites of the Nc-1 strain during early, mid and late gestation. Inflammation in early gestation was generally moderate to severe. Differently in mid gestation, inflammation was mild to moderate and minimal to mild in late gestation. Generally cellular infiltrates were mainly characterised by the presence of CD3+, CD4+ and γδ T-cells; whereas CD8+ and NK cells were less numerous. Macrophages were detected in larger numbers during later time-points after infection. A moderate to severe infiltration of IL-12, IFN-γ and TNF-α expressing cells was observed in the placentas collected in early gestation. This infiltration was more pronounced in the samples of placentome collected from dams carrying a dead foetus or in those that had aborted, compared with mothers carrying live foetuses at the time of sampling. The distribution of the cellular subsets observed in the three studies was similar. However, cellular infiltrates were more severe following infection during the first trimester in comparison to the second and third trimester. Similarly, the infiltration of Th1 cytokine expressing-cells was more severe in early gestation compared with the milder and more minimal infiltrations observed following N. caninum infection in mid and late gestation, respectively. These results may explain the milder clinical outcome observed when animals are infected in later stages of pregnancy.

The papers included in this thesis examine the host–parasite relationship in small and large animals following experimental challenges with Neospora caninum. This apicomplexan parasite is a major cause of abortion and reproductive losses in cattle worldwide. Economic and welfare issues make the development of a vaccine against the transplacental transmission of Neospora highly desirable. This thesis evaluates the host-parasite interactions in a non-pregnant mouse model examining whether the actively multiplying stage of the parasite (tachyzoite) could be attenuated through prolonged in vitro cultivation (passage) and used as a live vaccine. We show that continued maintenance of tachyzoites in tissue culture produced significantly reduced levels of morbidity and mortality in the mice following challenge, compared to mice receiving virulent parasites. Inoculation with a sub-lethal dose of tachyzoites was shown to protect against a subsequent lethal challenge of virulent parasites. Mice showing higher levels of cell mediated immunity (CMI) (antigen-specific splenocyte proliferation and interferon-γ (IFN-γ) production) had lower parasite burdens compared to mice with less pronounced CMI responses. Combined, these works show that it is possible to protect against a lethal challenge using attenuated tachyzoites and that a strong T-helper Type-1 CMI response is involved in protection and in reducing clinical disease severity. As the most commonly known route of infection with N. caninum is transplacental, from dam to foetus, we also wanted to examine the host-parasite relationship in pregnant cattle. This was done through the serial examination of the maternal and foetal immune responses of experimentally challenged cattle under controlled conditions at different stages throughout pregnancy. These works show the importance of the timing, location and magnitude of multiple components of the host immune response in determining foetal survival and also whether vertical transmission occurs. We show that both the maternal and foetal immune responses are critical in determining the clinical outcome of infection. A strong maternal CMI response was shown to aid foetal survival by reducing the numbers of parasites reaching and thus damaging the placenta. Due to the syndesmychorial nature of the ruminant placenta, any foetal responses observed are as a result of foetal infection. These experiments show that as pregnancy progresses the foetus goes from being immunologically immature and incapable of mounting a protective immune response (70 days of gestation (dg)) to becoming capable of mounting parasite-specific humoral, innate and CMI responses from around 140dg onwards. The experiments in pregnant cattle confirm the importance of parasite-specific proliferation and IFN-γ production, in reducing the magnitude of the parasite challenge reaching the maternal–foetal interface and aiding foetal survival. We also examined the immunodominant parasite peptides expressed in HPLC fractionated tachyzoite antigen, which are recognised by the cellular immune response of experimentally challenged cattle. Through LC-ESI-MS/MS, 6 Neospora proteins (including SAG1, SRS2 and GRA2) and a number of Toxoplasma gondii orthologues were identified and found to be recognised by CD4+ T-cells. These works collectively demonstrate the complexity of the host-parasite interaction in Neospora infections and show the importance of a CMI response in protection against the parasite.

The 16 publications presented in this thesis summarise the author’s contribution to seroepidemiological approaches for the diagnosis and monitoring of animal diseases of importance to New Zealand. The first four publications not only contribute to the above in relation to three important animal pathogens, namely Brucella ovis, Mycobacterium avium spp. paratuberculosis and Bovine Leukaemia Virus but also give an insight into more general consideration associated with the optimisation and validation of serological assays, namely regarding the definition and choice of gold standard reference sera, the determination of the cutoff threshold and discrimination between negative and positive reference populations. Two further publications deal with the establishment and validation of serological assays for the diagnosis of Neospora caninum infection and abortion in New Zealand. Then, baseline data were obtained for the sero-prevalence of the infection in dog and cattle populations in New Zealand. Three case studies provided initially information about the kinetics of serological responses after a N caninum abortion outbreak, and information about the usefulness of herd-based techniques rather than individual cowbased abortion diagnoses. A further study provided some early information about the mode of transmission seemingly predominating in New Zealand, which tends to be mainly via post-natal infection, in contrast to evidence provided by overseas researchers. A final case study, a longitudinal study of serological and other responses over a period of three years also provided data on the production effects of N caninum. The dissertation is completed by a number of reviews on sero-diagnosis of N caninum infection, its presence in Australasia and suggests finally control options, based on the present state of knowledge.

The 16 publications presented in this thesis summarise the author’s contribution to seroepidemiological approaches for the diagnosis and monitoring of animal diseases of importance to New Zealand. The first four publications not only contribute to the above in relation to three important animal pathogens, namely Brucella ovis, Mycobacterium avium spp. paratuberculosis and Bovine Leukaemia Virus but also give an insight into more general consideration associated with the optimisation and validation of serological assays, namely regarding the definition and choice of gold standard reference sera, the determination of the cutoff threshold and discrimination between negative and positive reference populations. Two further publications deal with the establishment and validation of serological assays for the diagnosis of Neospora caninum infection and abortion in New Zealand. Then, baseline data were obtained for the sero-prevalence of the infection in dog and cattle populations in New Zealand. Three case studies provided initially information about the kinetics of serological responses after a N caninum abortion outbreak, and information about the usefulness of herd-based techniques rather than individual cowbased abortion diagnoses. A further study provided some early information about the mode of transmission seemingly predominating in New Zealand, which tends to be mainly via post-natal infection, in contrast to evidence provided by overseas researchers. A final case study, a longitudinal study of serological and other responses over a period of three years also provided data on the production effects of N caninum. The dissertation is completed by a number of reviews on sero-diagnosis of N caninum infection, its presence in Australasia and suggests finally control options, based on the present state of knowledge.

The 16 publications presented in this thesis summarise the author’s contribution to seroepidemiological approaches for the diagnosis and monitoring of animal diseases of importance to New Zealand. The first four publications not only contribute to the above in relation to three important animal pathogens, namely Brucella ovis, Mycobacterium avium spp. paratuberculosis and Bovine Leukaemia Virus but also give an insight into more general consideration associated with the optimisation and validation of serological assays, namely regarding the definition and choice of gold standard reference sera, the determination of the cutoff threshold and discrimination between negative and positive reference populations. Two further publications deal with the establishment and validation of serological assays for the diagnosis of Neospora caninum infection and abortion in New Zealand. Then, baseline data were obtained for the sero-prevalence of the infection in dog and cattle populations in New Zealand. Three case studies provided initially information about the kinetics of serological responses after a N caninum abortion outbreak, and information about the usefulness of herd-based techniques rather than individual cowbased abortion diagnoses. A further study provided some early information about the mode of transmission seemingly predominating in New Zealand, which tends to be mainly via post-natal infection, in contrast to evidence provided by overseas researchers. A final case study, a longitudinal study of serological and other responses over a period of three years also provided data on the production effects of N caninum. The dissertation is completed by a number of reviews on sero-diagnosis of N caninum infection, its presence in Australasia and suggests finally control options, based on the present state of knowledge.