Background Infection with Campylobacter is thought to account for about 5% - 14% of all food and waterborne diarrhoea cases worldwide. By international standards, New Zealand has extremely high rates of campylobacteriosis which are thought to be the highest reported rates worldwide. The incidence has been steadily increasing since 1980 (when the disease became notifiable), reaching a peak of cases in 2003 (396/100,000). Although different surveillance systems complicate international comparisons, New Zealand's particularly high rate still lacks a conclusive explanation. Aims This study investigates the geographical distribution of campylobacteriosis in New Zealand and the relative importance of factors assumed to be affecting the distribution of this disease, including those related to climate, landuse, water and food. The approach aims to explain why certain areas might increase the probability of becoming infected. Methodology A Geographical Information System (GIS) is used to visualise the disease rate, investigate potential disease clustering and identify outliers. Hierarchical regression, including the analysis of residuals, is applied to analyse the variables in their complex interrelation and to investigate whether there is statistical evidence explaining the geographical variation in campylobacteriosis. This study is undertaken at the territorial local authority level, as all required data are available at this spatial scale and covers the period 1997 to 2005. Results and conclusion There is a large geographical variation in campylobacteriosis across New Zealand, ranging from an average annual rate of 97/100,000 to 526/100,000 per territorial local authority (TLA). Generally, there is statistical evidence for global and local clustering of the disease rate. There are upper and lower outliers of campylobacteriosis in New Zealand; however, higher rates primarily appear in the South Island. The hierarchical modelling confirms statistical significance for some of the environmental and sociodemographic variables. The final model explains about 58% of the variation in campylobacteriosis, and the residuals reflect this variation relatively accurately in approximately 75% of all TLAs. Although the evaluation of the results is confronted with a number of challenges, it is concluded that socioeconomic and demographic factors are crucial factors in explaining the observed spatial patterns in the notification data.

Background Infection with Campylobacter is thought to account for about 5% - 14% of all food and waterborne diarrhoea cases worldwide. By international standards, New Zealand has extremely high rates of campylobacteriosis which are thought to be the highest reported rates worldwide. The incidence has been steadily increasing since 1980 (when the disease became notifiable), reaching a peak of cases in 2003 (396/100,000). Although different surveillance systems complicate international comparisons, New Zealand's particularly high rate still lacks a conclusive explanation. Aims This study investigates the geographical distribution of campylobacteriosis in New Zealand and the relative importance of factors assumed to be affecting the distribution of this disease, including those related to climate, landuse, water and food. The approach aims to explain why certain areas might increase the probability of becoming infected. Methodology A Geographical Information System (GIS) is used to visualise the disease rate, investigate potential disease clustering and identify outliers. Hierarchical regression, including the analysis of residuals, is applied to analyse the variables in their complex interrelation and to investigate whether there is statistical evidence explaining the geographical variation in campylobacteriosis. This study is undertaken at the territorial local authority level, as all required data are available at this spatial scale and covers the period 1997 to 2005. Results and conclusion There is a large geographical variation in campylobacteriosis across New Zealand, ranging from an average annual rate of 97/100,000 to 526/100,000 per territorial local authority (TLA). Generally, there is statistical evidence for global and local clustering of the disease rate. There are upper and lower outliers of campylobacteriosis in New Zealand; however, higher rates primarily appear in the South Island. The hierarchical modelling confirms statistical significance for some of the environmental and sociodemographic variables. The final model explains about 58% of the variation in campylobacteriosis, and the residuals reflect this variation relatively accurately in approximately 75% of all TLAs. Although the evaluation of the results is confronted with a number of challenges, it is concluded that socioeconomic and demographic factors are crucial factors in explaining the observed spatial patterns in the notification data.

Bovine Genital Campylobacteriosis is characterized by early pregnancy loss and temporary infertility in cattle. The purpose of this project was to compare diagnostic approaches to detect Campylobacter fetus subsp. venerealis and evaluate the efficacy of vaccination for Bovine Genital Campylobacteriosis. This thesis describes the results of two studies that compared different sample preparation methods for bovine vaginal mucus for real-time PCR and assessed a commercial vaccine in preventing infection and reproductive loss. The first study compared real-time PCR utilizing different bovine vaginal mucus sample preparation techniques to direct culture. The magnetic bead based protocol demonstrated higher sensitivity (48.4%, P=0.02) and lower specificity (78.9%, P=0.01) than the heat lysis protocol which involved an additional dilution step (Sens=29.4%, Spec=88.2%), but did not differ from the heat lysis protocol without sample dilution (Sens=35.0%, P=0.16; Spec=81.1%, P=0.62). The sample preparation method, designed for bovine preputial samples (Chaban et al. 2012. Can J of Vet Res; 76: 166), did not work well for vaginal mucus. All modifications of that method and magnetic bead based extraction technique had low sensitivity compared to culture probably due to the biophysical properties of vaginal mucus, which could cause loss of targeted DNA during processing, or repeated sample freezing and thawing. Release of DNA directly from vaginal mucus by a modified heat lysis protocol with consequent real-time PCR could be a promising rapid screening approach after validating on fresh samples. The second study compared the risk of infection and reproductive failure in heifers, vaccinated with a commercial multivalent vaccine containing C. fetus antigen, to heifers vaccinated with a comparable product without C. fetus, that were exposed to infected bulls. There was no significant difference between groups either in risk of Campylobacter fetus subsp. venerealis isolation (P>0.17) or in the proportion of heifers that cultured positive at least once (P=0.42), as well as in the median number times of cultured positive samples (P=0.24) and the time to first cultured positive (P=0.67). There was no difference by treatment in the weekly proportions of heifers diagnosed pregnant by either ultrasound (P>0.31) or serum concentration of pragnancy specific protein B (P>0.31) during the study, as well as in the time to first pregnancy for heifers ever diagnosed as pregnant (P=0.30) and those that remained pregnant at the end of the study (P=0.70). Similarly, the difference was not detected by treatment in the proportion of animals, ever detected pregnant during the study (P=0.57) and in pregnancy loss rates (P=0.28). However, heifers that aborted were 4 times more likely to be cultured positive than those that did not abort (P=0.01). Heifers that were not pregnant at the end of the study cultured positive 1.5 times more often than pregnant animals in treatment group (P=0.04), while in control group such difference was 4 times (P=0.01). Heifers that were not pregnant at the end of the study did not differ by treatment in the number of times cultured positive (P=0.14). In this study, the mean concentrations of ELISA antibodies to C. fetus after vaccination were more than 2 times higher in treatment group than in control group (P<0.02), but vaccination did not significantly reduce infection or improve pregnancy in heifers when exposed to Cfv-infected bulls. Sample preparation technique is important for successful real-time PCR; release of DNA directly from a CVM sample by a modified heat lysis protocol was easy to perform and could be promising as a rapid screening approach for Bovine Genital Campylobacteriosis after validating on fresh samples. Vaccinating of heifers with a polyvalent commercial vaccine, containing Campylobacter fetus antigen, according to the label, did not significantly reduce infection rate or improve reproductive performance when they were naturally challenged.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-06-15T12:56:45Z No. of bitstreams: 1 Erica Chaves Lucio.pdf: 1028882 bytes, checksum: 29cc8b98781f5b6d52ee6c3c52e13e9b (MD5) / Made available in DSpace on 2016-06-15T12:56:45Z (GMT). No. of bitstreams: 1 Erica Chaves Lucio.pdf: 1028882 bytes, checksum: 29cc8b98781f5b6d52ee6c3c52e13e9b (MD5) Previous issue date: 2016-02-15 / The objective of this study was to determine the occurrence and risk factors associated with infection with Campylobacter spp. in sheep creations in the micro-region Garanhuns, State of Pernambuco, Brazil. Were collected 421 fecal samples from sheep flocks coming 20 for the isolation of Campylobacter spp. and Campylobacter jejuni and Campylobacter fetus species were identified by Polymerase Chain Reaction (PCR). To analyze the risk factors logistic regression was performed from the questionnaire with objective questions about the hygienic-sanitary and reproductive management. The occurrence of Campylobacter spp. it was 4.5% (19/421; C.I. 2.8% - 7.1%). The 19 positive samples in cultivation, eight (1.9% CI 0.9% - 3.9%) were classified as C. fetus subsp. fetus and seven (1.7% CI 0.7% - 3.5%) as C. jejuni, coinfected with four stool samples (0.95%). The number of identified focus was 35.0% (7/20) of the creations of sheep that had at least one positive animal. In logistic regression analysis did not identify any of the variables as a risk factor. This is the first report of infection with Campylobacter spp. in sheep herds in northeastern Brazil, and it is concluded that infection occurs in those herds. Thus, it is necessary to implement prevention and control measures to prevent the propagation of agent between the creations, avoiding damage to sheep production and risk to public health, since campylobacteriosis is considered an emerging zoonosis. / Objetivou-se com este estudo determinar a ocorrência e os fatores de risco associados à infecção por Campylobacter spp. em criações de ovinos na microrregião Garanhuns, no estado de Pernambuco, Brasil. Foram coletadas 421 amostras fecais de ovinos procedentes de 20 rebanhos para o isolamento de Campylobacter spp. As espécies Campylobacter fetus subsp. fetus e Campylobacter jejuni foram identificadas por Reação em Cadeia da Polimerase (PCR). Para análise dos fatores de risco foi realizada uma análise univariada e posteriormente regressão logística a partir de questionário com perguntas objetivas sobre o manejo higiênico-sanitário e reprodutivo. A ocorrência para Campylobacter spp. foi de 4,5% (19/421; I.C. 2,8% - 7,1%). Das 19 amostras positivas no cultivo, oito (1,9%; I.C. 0,9% - 3,9%) foram classificadas como C. fetus subsp. fetus e sete (1,7%; I.C. 0,7% - 3,6%) como C. jejuni, com co-infecção em quatro amostras (0,95%). O número de focos identificados foi de 35,0% (7/20) das criações de ovinos que apresentavam pelo menos um animal positivo. Na análise de regressão logística não foi identificada nenhuma das variáveis como fator de risco. Este é o primeiro registro da infecção por Campylobacter spp. em rebanhos ovinos no Nordeste do Brasil, concluindo-se que a infecção ocorre nesses rebanhos. Dessa forma, se faz necessário à implementação de medidas de controle e prevenção, para impedir a propagação do agente entre as criações, evitando prejuízos para ovinocultura e risco para saúde pública, uma vez que a campilobacteriose é considerada uma zoonose emergente.

A ovinocultura é um sistema de criação muito antigo em nosso país e ainda continua apresentando uma série de problemas que dificultam a produção econômica desses animais e necessitam de urgentes soluções. Visando minorar estes prejuízos esta pesquisa foi idealizada com o intuito de realizar um estudo minuncioso das principais enfermidades reprodutivas parasitárias e bacterianas. Todos os animais foram submetidos ao exame clínico geral e específico do sistema reprodutor e colheram-se amostras de soro, sêmen, abortamentos, lóquios, secreções, fezes e zaragatoa prepucial e vaginal dependendo da enfermidade a ser estudada. Não foi possível o isolamento nos fetos de nenhum agente etiológico. Conclui-se que a toxoplasmose é a enfermidade de maior importância nos rebanhos de estado de São Paulo e a de maior fator de risco em casos de abortamentos, a neosporose estaria relacionada principalmente com animais que apresentam repetição de cio, leptospirose foi observado em baixa titulação e a mais prevalente foi a Leptospira australis sorovar australis proveniente de animais silvestres, a campilobacteriose e a brucelose são as duas enfermidades da reprodução com menor ocorrência no estado. Foi isolado o primeiro caso de endometrite no Brasil por Histophilus somni. Foi isolado o primeiro caso de orquite por Actinobacillus seminis no estado de São Paulo. / Sheep industry is a traditional system in Brazil and presents a series of issues that complicate economical exploitation and urgently need solution. In order to reduce losses this research was idealized to carefully study the major bacterial and parasitary reproductive diseases. All animals were submitted to a general and specific reproductive system clinical examination. Blood, semen, abortions, lochia, vaginal discharges, feces, and preputial/vaginal swabs were collected according to the studied disease. It was not possible to isolate any etiological agent from aborted fetuses. The conclusion was that toxoplasmosis was the major disease on São Paulo herds and has the biggest risk factor in abortions, neosporosis would be related to animals that present heat repetition, leptospirosis was observed with low antibodies titles and the most prevalent was Leptospira australis sorovar australis arising from wild animals, campilobacteriosis and brucellosis are both the reproductive diseases with the lowest occurrence in the state. The first endometritis case caused by Histophilus somni. In Brazil was isolated. The first orchitis case caused by Actinobacillus seminis in São Paulo state was isolated.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-02-07T13:04:40Z No. of bitstreams: 1 Jonas de Melo Borges.pdf: 1057256 bytes, checksum: 5a36d4a5894648ecc348d8146d19bca1 (MD5) / Made available in DSpace on 2017-02-07T13:04:40Z (GMT). No. of bitstreams: 1 Jonas de Melo Borges.pdf: 1057256 bytes, checksum: 5a36d4a5894648ecc348d8146d19bca1 (MD5) Previous issue date: 2016-07-20 / The objective of this study was to determine the occurrence of infection with Campylobacter fetus subsp. venerealis and Tritrichomonas foetus in buffaloes in the State of Pernambuco, Brazil and identify possible risk factors associated with infection. Biological samples were collected (cervico vaginal mucus and shaved prepucial) of 113 animals, coming from 8 properties in different regions of the state. The biological material collected was transferred into phosphate buffered saline (PBS) and inoculated in the specific transport, Lander for diagnosis of C. fetus subsp. venerealis and Diamond for T. fetus subsequently. For the diagnosis of infection by Campylobacter fetus subsp. venrealis and Tritrichomonas foetus the samples were submitted to Polymerase Chain Reaction ( PCR) grown in Columbia agar plus antibiotics and Diamond, respectively. There was an occurrence of 1.8% (2/113 ; I.C. 0.2 to 6.2 % ) of positive animals in the microbiological examination with confirmation by PCR, for C. fetus subsp. venerealis. It was observed that 100% of positive samples were from two (2) males from the same herd. No animals were positive for T. foetus. It was not possible to identify risk factors associated with infection. This is the first report of infection with C. fetus subsp. venerealis in buffaloes in Brazil. Despite the low occurrence it is recommended that control measures are adopted, in order to prevent the spread of the agent to other herds. / Objetivou-se com este estudo determinar a ocorrência da infecção por Campylobacter fetus subsp. venerealis e Tritrichomonas foetus em búfalos no Estado de Pernambuco, Brasil e identificar os possíveis fatores de risco associados às infecções. Foram coletadas amostras biológicas (muco cérvico-vaginal e raspado prepucial) de 113 animais, procedentes de 8 propriedades, de diferentes regiões do Estado. O material biológico coletado foi transferido para solução salina tamponada (PBS) e posteriormente inoculado nos meios de transporte específicos, Lander para diagnóstico de C. fetus subsp. venerealis e Diamond para T. foetus. Para o diagnóstico das infecções por Campylobacter fetus subsp. venerealis e Tritrichomonas foetus as amostras foram cultivadas em meio ágar columbia acrescido de antibiótico e Diamond, respectivamente. Posteriormente as amostras de PBS foram submetidas à Reação em Cadeia da Polimerase (PCR). Para pesquisa de C. fetus subsp. venerealis, observou-se uma ocorrência de 1,8% (2/113; I.C. 0,2 – 6,2%) de animais positivos no exame microbiológico com confirmação pela PCR. Em relação à procedência, observou-se que 100% das amostras positivas pertenciam a dois machos do mesmo rebanho. Na pesquisa de T. foetus nenhum animal foi positivo. Não foi possível identificar os fatores de risco associados às infecções. Este é o primeiro registro da infecção por C. fetus subsp. venerealis em búfalos no Brasil. Apesar da baixa ocorrência recomenda-se que medidas de controle sejam adotadas, com o intuito de evitar a disseminação do agente para outros rebanhos.

Tyrimo tikslas – disertaciniame darbe suplanuotų atlikti tyrimų tikslas buvo įvertinti broilerių pulkų ir mažmeninėje prekyboje parduodamos paukštienos (broilerių sparnelių ir blauzdelių) užkrėstumo kampilobakterijomis sąsajas su žmonių susirgimais kampilobakterioze bei kampilobakterijų atsparumą antimikrobinėms medžiagoms Lietuvoje. Darbo tikslui pasiekti buvo atlikti tyrimai pagal šiuos numatytus uždavinius: 1. Nustatyti broilerių pulkų ir šviežios paukštienos produktų – sparnelių ir blauzdelių užkrėstumą kampilobakterijomis. 2. Įvertinti sąsajas tarp kampilobakterijų paplitimo paukštienos gamybos grandinėje ir žmonių susirgimų kampilobakterioze atsižvelgiant į išskirtų kampilobakterijų padermių genetinius panašumus ar skirtumus. 3. Palyginti iš skirtingų šaltinių išskirtų kampilobakterijų padermių atsparumą antimikrobinėms medžiagoms. 4. Įvertinti broilerių užsikrėtimo intensyvumo kampilobakterijomis įtaką galimam skerdenėlių užkrėstumui skerdimo metu. Tyrimai, kurių metu buvo išskiriamos kampilobakterijos iš broilerių pulkų, paukštienos produktų, bei žmonių klinikinių išmatų mėginių, atlikti vienerių metų (2009–2010) laikotarpiu. Tyrimų metu buvo įvertintas broilerių pulkų bei prekybos vietose parduodamų paukštienos produktų užkrėstumas kampilobakterijomis bei atliktas C. coli ir C. jejuni padermių, išskirtų iš broilerių pulkų, paukštienos produktų ir žmonių išmatų mėginių, genetinis charakterizavimas taikant RFIP metodą. Tokie tyrimai Lietuvoje atlikti pirmą kartą ir... [toliau žr. visą tekstą] / Aim of the study: the aim of the research was to estimate the level of contamination with Campylobacter spp., of poultry meat sold at retail (broiler wings and drumsticks) in connection with human campylobacteriosis cases in Lithuania, as well as antimicrobial resistance of Campylobacters isolated from both sources. To achieve the aim, research under the followings objectives has been carried out: 1. To evaluate the rate of contamination with Campylobacter spp. of broiler flocks and poultry products – wings and drumsticks. 2. To estimate the links between prevalence of Campylobacter spp. in poultry meat production chain and human cases of campylobacteriosis with regard to genetic diversity of Campylobacter spp. isolates. 3. To compare the antimicrobial resistance of Campilobacter spp. strains isolated from poultry meat production chain and human campylobacteriosis cases. 4. To evaluate the influence of quantitative load of Campylobacter spp. in broilers gastrointestinal tract to likely contamination of broiler carcasses during processing. The research, at which Campylobacter spp. were isolated from broiler flocks, poultry products and human stool samples, was conducted in a period of one year (2009–2010). With this study we evaluated the contamination of broiler flocks and poultry meat sold at retail with Campylobacter spp., genetic characterisation of C. coli and C. jejuni isolates from broiler flocks, poultry meat and human stool samples was made using the RFLP method... [to full text]

A ovinocultura é um sistema de criação muito antigo em nosso país e ainda continua apresentando uma série de problemas que dificultam a produção econômica desses animais e necessitam de urgentes soluções. Visando minorar estes prejuízos esta pesquisa foi idealizada com o intuito de realizar um estudo minuncioso das principais enfermidades reprodutivas parasitárias e bacterianas. Todos os animais foram submetidos ao exame clínico geral e específico do sistema reprodutor e colheram-se amostras de soro, sêmen, abortamentos, lóquios, secreções, fezes e zaragatoa prepucial e vaginal dependendo da enfermidade a ser estudada. Não foi possível o isolamento nos fetos de nenhum agente etiológico. Conclui-se que a toxoplasmose é a enfermidade de maior importância nos rebanhos de estado de São Paulo e a de maior fator de risco em casos de abortamentos, a neosporose estaria relacionada principalmente com animais que apresentam repetição de cio, leptospirose foi observado em baixa titulação e a mais prevalente foi a Leptospira australis sorovar australis proveniente de animais silvestres, a campilobacteriose e a brucelose são as duas enfermidades da reprodução com menor ocorrência no estado. Foi isolado o primeiro caso de endometrite no Brasil por Histophilus somni. Foi isolado o primeiro caso de orquite por Actinobacillus seminis no estado de São Paulo. / Sheep industry is a traditional system in Brazil and presents a series of issues that complicate economical exploitation and urgently need solution. In order to reduce losses this research was idealized to carefully study the major bacterial and parasitary reproductive diseases. All animals were submitted to a general and specific reproductive system clinical examination. Blood, semen, abortions, lochia, vaginal discharges, feces, and preputial/vaginal swabs were collected according to the studied disease. It was not possible to isolate any etiological agent from aborted fetuses. The conclusion was that toxoplasmosis was the major disease on São Paulo herds and has the biggest risk factor in abortions, neosporosis would be related to animals that present heat repetition, leptospirosis was observed with low antibodies titles and the most prevalent was Leptospira australis sorovar australis arising from wild animals, campilobacteriosis and brucellosis are both the reproductive diseases with the lowest occurrence in the state. The first endometritis case caused by Histophilus somni. In Brazil was isolated. The first orchitis case caused by Actinobacillus seminis in São Paulo state was isolated.

The traditional method for the diagnosis of bovine genital campylobacteriosis is the culture and identification of the causative organism, Campylobacter fetus subsp. venerealis (Cfv) from the genital tract. This approach is considered relatively insensitive due to the fragility of the bacteria, their specific nutritional and atmospheric requirements and their being easily overgrown by commensal bacteria. The identification of isolates is also problematic due to the limited biochemical activity of the bacteria. With the rapid advances made in the molecular field, assays have become more robust and cost-effective making them feasible for the diagnostic laboratory. The potential speed, sensitivity and specificity offered by these assays provide attractive alternatives for the identification of pathogens which are notoriously difficult to identify. The first part of this investigation was concerned with the implementation and evaluation of a polymerase chain reaction (PCR) assay for the direct detection of C. fetus in bovine preputial specimens. The specificity of a published C. fetus-specific primer pair was established by testing C. fetus reference and field isolates in addition to a collection of other Campylobacter species and organisms which may encountered in the genital tract of cattle. All C. fetus isolates tested yielded a single PCR amplicon of approximately 750 bp. No amplicons were generated when any of the other non-C. fetus isolates were tested. Following minor modifications to the assay, the sensitivity of the assay was determined using spiked Weybridge medium. A detection limit of 615 Cfv/mR Weybridge medium (or 6,15 cell equivalents per PCR assay) was obtained. Preputial material collected and submitted for laboratory testing may often be contaminated with faeces, urine, semen and/or blood. All of these components are known to be potential PCR inhibitors and the influence of each, on the sensitivity of the PCR assay, was subsequently evaluated. Faeces were identified as a potent inhibitor and contamination of specimens with as little as 1% (w/v) faeces reduced the sensitivity of the assay. Concentrations of up to 50% (v/v) of blood, urine and semen had no effect on the sensitivity of the assay. Preputial specimens, collected in Weybridge medium, were subsequently pooled and spiked and used to establish the sensitivity of both the PCR and culture methods as well as determine the influence of time on the sensitivity of the assays. Testing was carried out in triplicate on samples collected from different herds which were ascertained to be free of Cfv based on the use of specific selection criteria. The detection limit of the culture method was found to be better than that achieved using PCR only immediately after the samples were spiked. The detection limit of the culture method decreased with time whilst the detection limit of the PCR assay remain unchanged up to 72 hours post-inoculation. Ensuing field evaluation involved the testing of 212 clinical samples using both the culture method and the optimized PCR assay. Of the samples tested 4,2% were found to be positive using the PCR assay, whilst only 3,8% were found to be positive by culture. Based upon this evaluation the analytical specificity of the PCR assay was calculated to be 99% and the analytical sensitivity, 85,7%. The second part of this investigation was concerned with the subspeciation of C. fetus isolates. Currently the only test recommended by the Office International des Epizooties (OIE) for the subspeciation of isolates, is tolerance to 1% glycine. Doubts over the reliability of this test have led to alternative or supplementary tests being sought. Within the context of this investigation a collection of 40 South African field isolates were subspeciated using a previously described subspecies-specific primer set as well as the traditional 1% glycine tolerance phenotyping test. Additionally, other phenotyping tests (selenite reduction, growth at 42 °C and susceptibility to metronidazole and cefoperazone) were evaluated to determine their suitability for use as an aid in the subspeciation of C. fetus isolates. None of the field isolates yielded a Cfv-specific subspecies PCR amplicon using the published primer set suggesting that all of the isolates were Campylobacter fetus subsp. fetus (Cff). Based on tolerance to 1% glycine however, only 6 isolates were identified as Cff (glycine tolerant), whilst the remainder were classified as Cfv. The results of the ‘sensitive’ hydrogen sulphide test indicated that the Cfv isolates were specifically Cfv biovar intermedius. The lack of agreement between the PCR and the phenotyping subspeciation results concur with the findings reported by other researchers. It is consequently concluded that the published VenSF/VenSR subspecies-primer set is unsuitable for the subspeciation of South African field isolates. / Dissertation (MSc)--University of Pretoria, 2008. / Veterinary Tropical Diseases / unrestricted

Public health costs of foodborne campylobacteriosis are estimated to cost more than a billion dollars in the United States annually. This pathogen has been primarily associated with chicken production and processing which is a ~$33 billion industry. To further identify practices that could reduce Campylobacter presence, concentration, and persistence in chicken prior to consumption a quantitative microbial risk assessment (QMRA) was conducted for boneless, skinless chicken breast meals prepared and consumed domestically in the contiguous United States. This QMRA model was developed with @RISK software (Palisade Corp., Ithaca, NY) and data inputs can be easily modified and updated. QMRA is a powerful analytic method that can be utilized to model the dynamics between the food pathogen, food commodity, and ingestion. It provides insight into the impacts of the process in its interaction and its surrounding environment. The baseline model determined that consumption of this product resulted in annual means of infections: 328,257, illnesses: 108,174, hospitalizations: 27,754, deaths: 37, cases of Campylobacter-associated Guillain-Barré Syndrome (GBS): 1,373, and cases of Campylobacter-associated Irritable Bowel Syndrome (IBS): 9,501. The associated annual economic burdens were ~$192 million for acute campylobacteriosis, ~$77 million for GBS, and ~$96 million for IBS. The effects of targeting and modifying the baseline model's inputs within the farm-to-fork process were studied as follows: Post grow-out (1) prevalence and (2) concentration of Campylobacter on chickens at the farm prior to transport, (3) transport crate cleaning frequency prior to loading, (4) temperature storage conditions at post processing/ pre-retail, (5) the frequency of handwashing in the preparation and handling of a chicken meal, and (6) the combination Campylobacter mitigation models using the inputs from (2) and (4). Mean yearly illnesses are estimated to decrease by approximately half if on-farm Campylobacter prevalence was lowered to 35-50% from the baseline level of 76%. An additional ~50,000 illnesses can be expected if the proportion of home preparers who do not wash their hands increases from 8.3% (baseline) to 20%. The combined effects of reducing on-farm Campylobacter concentrations and increasing the proportion of product frozen in-plant have greater impacts on reducing yearly campylobacteriosis and associated costs than either intervention alone. / Doctor of Philosophy / Campylobacter is a major foodborne bacterial pathogen that is not well known by the general public, although public health costs are estimated to cost more than a billion dollars in the United States annually. Chicken production is a ~$33 billion industry that is affected by the contamination of this pathogen. In this study, a quantitative microbial risk assessment (QMRA) was performed to study the impact of Campylobacter on chicken meals prepared in the home. Societal and economic burdens were evaluated as well. The models developed provide comprehensive simulations that describe the spread, persistence, and the concentration of Campylobacter throughout the farm to fork process in the annual consumption of boneless, skinless chicken breast meals prepared and consumed domestically in the contiguous United States. Additional simulation models were created to compare methods for reducing Campylobacter along the food chain that could lead to fewer cases of campylobacteriosis in the United States, or what could happen if there was a breakdown in a hygiene step in the preparation of the chicken meal.