Detection of Coxiella burnetii in the mammary gland of a dairy goat

The zoonotic bacterium Coxiella (C.) burnetii can be excreted by infected goats through birth products and milk. The detection of C. burnetii DNA in the mammary gland tissue of infected dairy goats and intermittent milk shedders has been reported, but confirmation of C. burnetii bacteria in the udder remained pending. The pathogen caused abortions in a 152-head dairy goat herd, resulting in the vaccination against C. burnetii of the entire herd with annual boosters. To monitor the C. burnetii shedding at herd level, monthly bulk tank milk (BTM) samples were analyzed using PCR (IS1111). Despite vaccination, C. burnetii DNA was detected in BTM samples within the first 16 months of the study. Therefore, individual milk samples were tested on four different occasions several months apart to identify potential intermittent milk shedders. Only one goat (#67455) tested positive three times. This goat was necropsied to investigate the presence of C. burnetii in the udder and other organs. PCR detected C. burnetii DNA solely in both mammary glands and the left teat cistern. Immunohistological examination identified C. burnetii antigen in mammary gland tissue, confirmed by the detection of C. burnetii bacteria in the mammary epithelial cells using fluorescence in situ hybridization. The removal of goat #67455 led to negative BTM samples until the end of the study. The findings demonstrate the occurrence of C. burnetii in the mammary gland of a naturally infected and vaccinated goat. The presence possibly contributed to intermittent milk shedding of goat #67455, and the mammary gland tissue may serve as a replicative niche for C. burnetii.

Efficacy and Safety of an Inactivated Phase I Coxiella burnetii Vaccine to Control Q Fever in Ruminants: A Systematic Review

Q fever is a disease caused by Coxiella burnetii that affects many animal species and humans. In ruminants, the disease is responsible for several reproductive disorders (such as abortions, stillbirths, premature births, weak offspring, retained foetal membranes and infertility). An inactivated vaccine based on a phase I antigen of C. burnetii is available for cattle, goats and sheep. This review aims to summarise the scientific literature regarding the efficacy and safety of this vaccine to control the infection in these three domestic ruminant species. Forty-five publications and one experimental veterinary thesis reporting on experimental studies, case reports, mathematical modelling and intervention studies were selected according to the PRISMA guidelines. Although some studies lack control groups or statistical analyses, for all three species, published data show that vaccination often results in a reduction in abortions and an improvement in reproductive performance in comparison with absence of vaccination. There is also evidence, including in infected herds and animals, that vaccination is associated with a reduction in bacterial shedding, both in intensity and duration in comparison with absence of vaccination. For these reasons, in case of human outbreaks, vaccination is one of the pillars of control measures. Vaccination is generally well tolerated, despite the rare occurrence of mild, transient side-effects, such as hyperthermia and reduction in milk yield.

Which Factors Influence the Consumption of Antibiotics in Q-Fever-Positive Dairy Farms in Northern Germany?

It was the aim of this study to examine whether the usage of the vaccine COXEVAC® (Ceva Santé Animale) could reduce the consumption of antibiotics in Q-fever-positive dairy farms. Additionally, the effects of other herd-level factors on the consumption of antibiotics were investigated. A total of 36 farms with vaccination and 13 farms without vaccination participated in this longitudinal cohort study. In all herds, Coxiella burnetii had been directly or indirectly diagnosed. To compare the treatment frequency of antibiotics between the vaccinated group and the non-vaccinated group, the consumption of antibiotics for each farm was collected using the veterinary documents about the application and delivery of antibiotics. To gather detailed information about herd data, nutrition, milking management, housing, and animal health, the farmers were interviewed with the help of a questionnaire. The results thereof suggest that there might be an association between the vaccination against Q fever and a reduced consumption of antibiotics. Neither herd size nor milk yield level influenced the consumption of antibiotics in the study herds. Type of flooring and udder-cluster disinfection while milking were associated with a lower and higher therapy frequency, respectively. Further studies are necessary to elucidate the cause-effect relationship between vaccination and the consumption of antibiotics.

Coxiella burnetii Seroprevalence and Associated Risk Factors in Cattle, Sheep, and Goats in Estonia

Q fever, a disease caused by Coxiella burnetii (CB), is an emerging zoonotic health problem. The prevalence data from potential sources are valuable for assessing the risk to human and animal health. To estimate the prevalence of CB antibodies in Estonian ruminants, pooled milk and serum samples from cattle (Bos taurus) and pooled serum samples from sheep (Ovis aries) and goats (Capra hircus) were analyzed. Additionally, bulk tank milk samples (BTM; n = 72) were analyzed for the presence of CB DNA. Questionnaires and herd-level datasets were used to identify the risk factors for exposure using binary logistic regression analysis. The prevalence of CB-positive dairy cattle herds (27.16%) was significantly higher than that in beef cattle herds (6.67%) and sheep flocks (2.35%). No CB antibodies were detected in the goat flocks. CB DNA was found in 11.36% of the BTM samples. The odds of seropositivity were higher in dairy cattle herds, with an increasing number of cattle in the herd, and with location in southwestern, northeastern and northwestern Estonia. Dairy cattle herds had higher odds of testing positive for CB in BTM if the dairy cows were kept loose and lower odds if the herd was located in northwestern Estonia.

Phenotype of Coxiella burnetii Strains of Different Sources and Genotypes in Bovine Mammary Gland Epithelial Cells

Despite the high prevalence of C. burnetii in dairy herds and continuous shedding via milk by chronically infected cows, bovine milk is not recognized as a relevant source of human Q fever. We hypothesized that the bovine mammary gland epithelial cell line PS represents a suitable in vitro model for the identification of C. burnetii-strain-specific virulence properties that may account for this discrepancy. Fifteen C. burnetii strains were selected to represent different host species and multiple loci variable number of tandem repeat analysis (MLVA) genotypes (I, II, III and IV). The replication efficiencies of all strains were similar, even though strains of the MLVA-genotype II replicated significantly better than genotype I strains, and bovine and ovine isolates replicated better than caprine ones. Bovine milk isolates replicated with similar efficiencies to isolates from other bovine organs. One sheep isolate (Cb30/14, MLVA type I, isolated from fetal membranes) induced a remarkable up-regulation of IL-1β and TNF-α, whereas prototypic strains and bovine milk isolates tended to suppress pro-inflammatory responses. While infection with strain Nine Mile I rendered the cells partially refractory to re-stimulation with E. coli lipopolysaccharide, Cb30/14 exerted a selective suppressive effect which was restricted to IL-6 and TNF-α and spared IL-1β. PS cells support the replication of different strains of C. burnetii and respond in a strain-specific manner, but isolates from bovine milk did not display a common pattern, which distinguishes them from strains identified as a public health concern.

A cross-sectional survey of risk factors for the presence of Coxiella burnetii in Australian commercial dairy goat farms

The largest Australian farm‐based outbreak of Q fever originated from a dairy goat herd. We surveyed commercial dairy goat farms across Australia by testing bulk tank milk (BTM) samples using a commercial indirect enzyme‐linked immunosorbent assay and two quantitative polymerase chain reactions (PCRs). Of the 66 commercial dairy goat herds on record, managers from 61 herds were contacted and 49 provided BTM samples. Five of the surveyed herds were positive on at least one of the diagnostic tests, thus herd‐level apparent prevalence was 10% (95% confidence interval [CI] 4 to 22). True prevalence was estimated to be 3% (95% credible interval: 0 to 18). Herd managers completed a questionnaire on herd management, biosecurity and hygiene practices and risk factors were investigated using multivariable logistic regression. Herds with >900 milking does (the upper quartile) were more likely to be Coxiella burnetii positive (odds ratio = 6.75; 95% CI 1.65 to 27.7) compared with farms with ≤900 milking does. The odds of BTM positivity increased by a factor of 2.53 (95% CI 1.51 to 4.22) for each order of magnitude increase in the number of goats per acre. C. burnetii was not detected in samples from the majority of the Australian dairy goat herds suggesting there is an opportunity to protect the industry and contain this disease with strengthened biosecurity practices. Intensification appeared associated with an increased risk of positivity. Further investigation is required to discriminate the practices associated with an increased risk of introduction to disease‐free herds, from practices associated with maintenance of C. burnetii infection in infected dairy goat herds.

Coxiella burnetii DNA in milk, milk products, and fermented dairy products

Introduction

Q fever in dairy cattle has been investigated in Latvia since 2012. In 2015, 10.7% of farms tested positive for the DNA of C. burnetii, its aetiological agent, in bulk tank milk. The presence of C. burnetii DNA and infectious bacteria in dairy products has been assessed in several countries, and because Latvian milk may contain them, parallel assessment in this country is recommended. Accordingly, the present study tested shop and farm retail dairy products from Latvia and included foreign products for comparison.

Material and Methods

Investigation was carried out of 187 samples of a diverse range of dairy products from 41 Latvian milk producers. Twenty-six comparable samples pooled from Estonia, France, Germany, Greece, Italy, Lithuania, the Netherlands, Poland and Spain were also included. The all-countries total number of fermented milk products was 160. Special attention was paid to products that could be more attractive to children because of their added chocolate, cacao, berry and fruit content. DNA was extracted and amplification of C. burnetii IS1111 was performed using a commercial PCR kit.

Results

Overall positivity was 60.56%. Domestic products were positive more often (60.96%) than foreign ones (57.69%). Only 26.67% of unpasteurised Latvian cow’s milk samples were positive whereas 76.47% of pasteurised equivalents and 63.13% of fermented milk products were. Sweetened and fruit-containing samples were 71.43% positive.

Conclusion

The shedding of C. burnetii via milk should be monitored and only milk from healthy animals allowed for sale for direct human consumption without pasteurisation. Raw milk quality and the effectiveness of industrial heat treatment and pasteurisation methods in Latvia and other countries should be carefully assessed to ensure adequate consumer health protection.

Epidemiological study of Coxiella burnetii in dairy cattle and small ruminants in Québec, Canada

The bacterium Coxiella burnetii (C. burnetii) can infect a wide range of animals, most notably ruminants where it causes mainly asymptomatic infections and, when clinical, it is associated with reproductive disorders such as abortion. It is also the etiological agent of Q fever in humans, a zoonosis of increasingly important public health concern. A cross-sectional study was performed to estimate the apparent prevalence and spatial distribution of C. burnetii positivity in dairy cattle and small ruminant herds of two regions of Québec, Canada, and identify potential risk factors associated with positivity at animal and herd levels. In dairy cattle herds, individual fecal samples and repeated bulk tank milk samples (BTM) were collected. In small ruminant herds, serum and feces were sampled in individual animals. ELISA analyses were performed on serum and BTM samples. Real-time quantitative PCR (qPCR) was done on fecal and BTM samples. An animal was considered C. burnetii-positive when at least one sample was revealed positive by ELISA and/or qPCR, while a herd was considered C. burnetii-positive when at least one animal inside that herd was revealed positive. None of the 155 cows had a qPCR-positive fecal sample, whereas 37.2 % (95 % CI = 25.3-49.1) of the 341 sheep and 49.2 % (95 % CI = 25.6-72.7) of the 75 goats were C. burnetii-positive. The apparent prevalence of C. burnetii-positive herds was 47.3 % (95 % CI = 35.6-59.3) in dairy cattle herds (n = 74), 69.6 % (95 % CI = 47.1-86.8) in sheep flocks (n = 23) and 66.7 % (95 % CI = 22.3-95.7) in goat herds (n = 6). No spatial cluster of positive herds was detected. At the individual level, the only significant association with positivity in multivariable regressions was higher parity number in small ruminants. At the herd level, the use of calving group pen, the distance to the closest positive bovine herd, and small ruminant herd density in a 5 km radius were associated with dairy cattle herd positivity, whereas small ruminant herds with more than 100 animals and with a dog on the farm had greater odds of C. burnetii positivity. Our study shows that the infection is frequent on dairy cattle and small ruminant herds from the two studied regions and that some farm and animal characteristics might influence the transmission dynamics of the C. burnetii infection.

Apparent prevalence and risk factors of coxiellosis (Q fever) among dairy herds in India

Coxiella burnetii is a highly infectious zoonotic pathogen infecting wide range of mammals, including humans. In the present study, a total of 711 blood samples from bovines [cattle (n = 543) and buffaloes (n = 168)] from eight farms at different geographical locations in India were screened for C. burnetii targeting the IS1111 and the com1 genes. The anti-C. burnetii antibodies in serum samples were detected using indirect-ELISA kits. Also, a total of 21 parameters pertaining to animal health and farm management were identified to assess their role as possible risk factors for coxiellosis among the targeted farms. The apparent prevalence (positive for PCR and/or ELISA) for coxiellosis was reported to be 24.5% in cattle and 8.9% in buffaloes. In cattle, the detection rate of C. burnetii employing the IS1111 gene (8.5%) was found to be significantly higher (p<0.05) as compared to the com1 (6.5%) gene. The seropositivity by ELISA was higher among cattle (17.7%) than in buffaloes (8.3%). Further, on univariable analysis of risk factors, species (cattle) (OR:3.31; 95%CI:1.88–5.82), inadequate floor spacing (OR:1.64; 95%CI:1.10–2.43), mastitis (OR:2.35, 95%CI:1.45–3.81) and reproductive disorders (OR:2.54; 95%CI:1.67–3.85) were significantly (p<0.05) having high odds for coxiellosis. The multivariable logistic regression analysis of the animal level risk factors revealed that species and age were found to be significantly associated with coxiellosis. However, since the number of screened farms is limited; further research is needed with a higher number of animals to confirm the farm level odds ratio of risk factors. Quarantine and biosecurity measures including farm hygiene operations were observed to be inadequate and also the lack of awareness about coxiellosis among the farm workers. In absence of vaccination program for coxiellosis in India, robust surveillance, farm biosecurity measures and the awareness for the disease among risk groups can play an important role in the disease prevention and subsequent transmission of the pathogen.

Identification of risk factors associated with Coxiella burnetii infection in cattle and buffaloes in India

The etiological agent Coxiella burnetii is a highly infectious gram-negative bacterium that can affect multiple species. Many reports confirm its presence in humans, domestic ruminants and rodents in India. This study was aimed to investigate the risk factors associated with C. burnetii infection in bovine populations in Punjab, India. This study was conducted using a stratified two-stage random sampling approach. Twenty-two villages representing all districts of the state were selected. Bovine farmers were interviewed and detailed information about their management and husbandry practices was collected using a structured questionnaire. Blood, milk and genital swab samples were collected from the cattle and buffaloes owned by the farmers. An animal was declared C. burnetii infected by using a combination of tests in parallel, i.e. if it was positive in serological or molecular tests (IgG indirect ELISA or Trans-PCR assay). A herd was considered positive if at least one animal in the herd was declared C. burnetii infected using the above definition. Three binomial logistic regression models were constructed to evaluate the association of (a) geographical location, herd characteristics, and farm management practices with the herd status (herd model), (b) individual animal related factors with the C. burnetii infection status (individual animal model), and (c) production and health related factors with C. burnetii infection status in adult females (adult female model). We collected a total of 610 blood, 610 genital swabs and 361 milk samples from 378 cattle and 232 buffaloes in 179 herds/households. The practice of throwing away aborted materials outside the farm as compared to burial/burning (adjusted odds ratio [OR] 3.0, 95 % confidence interval [CI] 1.14-7.87, p = 0.02) was associated with larger odds of being a C. burnetii infected herd. On the other hand, separation of the animals from the rest of the herd during parturition had a protective effect for being a C. burnetii infected herd (adjusted OR 0.31, 95 % CI 0.18-0.77, p = 0.01). Being cattle as compared to buffalo (adjusted OR 3.37, 95 % CI 1.23-9.20, p = 0.02) and older (adjusted OR 3.37, 95 % CI 1.23-9.20, p = 0.02) were associated with larger odds of C. burnetii infection. The current study highlights that farm practices such as improper aborted material disposal and not separating the animals from the rest of the herd during parturition are important risks for the occurrence of C. burnetii infection in the bovine populations in the state.

Real-time quantitative PCR-based detection of Coxiella burnetii in unpasteurized cow's milk sold for human consumption

Coxiella burnetii is a zoonotic pathogen with a worldwide distribution that is responsible for Q fever in humans. It is a highly infectious bacterium that can be transmitted from cattle to humans through the consumption of unpasteurized milk. We report the molecular identification of C. burnetii in raw cow's milk being sold directly for human consumption in Brazil without official inspection or pasteurization. One hundred and twelve samples of raw milk were analysed by real-time quantitative PCR (qPCR), and C. burnetii was detected in 3.57% (4/112) of the samples at a concentration ranging from 125 to 404 bacteria per millilitre. The identification of this zoonotic pathogen in raw milk sold directly for human consumption is a public health concern since C. burnetii can be transmitted through the oral route. This result indicates that health education and other preventive measures should be officially implemented in Brazil to prevent the spread of infection. To our knowledge, this is the first qPCR-based detection of C. burnetii in raw milk samples from cows sold in Brazil that do not undergo official inspection or pasteurization.

The prevalence of Coxiella burnetii shedding in dairy goats at the time of parturition in an endemically infected enterprise and associated milk yield losses

Background

This was a panel study of the prevalence of C. burnetii infection in does in an endemic dairy goat enterprise in Victoria, Australia. Our first objective was to determine the prevalence of does shedding C. burnetii at the time of parturition and to quantify the concentration of genome equivalents (GE) present in each C. burnetii positive sample. Our second objective was to determine the proportion of positive does that were persistent shedders. Our final objective was to quantify the association between C. burnetii qPCR status at the time of kidding and daily milk volumes produced during the subsequent lactation.

Results

Vaginal swabs (n= 490) were collected from does at the time of kidding and analysed using a quantitative polymerase chain reaction (qPCR) assay. Shedding of C. burnetii was detected in 15% (95% CI: 12% to 18%) of the sampled does. Does were classified as qPCR-negative, qPCR-positive low and qPCR-positive high based on the estimated concentration of GE from the qPCR. Persistent shedding at relatively low concentrations was detected in 20% (95% CI: 10% to35%) of shedding does sampled again at their subsequent parturition. After controlling for possible confounders and adjusting for variation in daily milk yields at the individual doe level, daily milk yields for qPCR-positive high does were reduced by 17% (95% CI: 3% to 32%) compared to qPCR-negative does (p= 0.02).

Conclusions

Shedding concentrations of C. burnetii were highly skewed, with a relatively small group of does shedding relatively high quantities of C. burnetii. Further, high shedding does had reduced milk yields compared to qPCR-negative does. Early detection and culling of high shedding does would result in increased farm profitability and reduce the risk of Q fever transmission.

Q fever in Egypt: Epidemiological survey of Coxiella burnetii specific antibodies in cattle, buffaloes, sheep, goats and camels

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii. Clinical presentation in humans varies from asymptomatic to flu-like illness and severe sequelae may be seen. Ruminants are often sub-clinically infected or show reproductive disorders such as abortions. In Egypt, only limited data on the epidemiology of Q fever in animals are available. Using a stratified two stage random sampling approach, we evaluated the prevalence of Coxiella burnetii specific antibodies among ruminants and camels in 299 herds. A total of 2,699 blood samples was investigated using enzyme-linked-immunosorbent assay (ELISA). Coxiella burnetii specific antibodies were detected in 40.7% of camels (215/528), 19.3% of cattle (162/840), 11.2% of buffaloes (34/304), 8.9% of sheep (64/716) and 6.8% of goats (21/311), respectively. Odds of seropositivity were significantly higher for cattle (aOR: 3.17; 95% CI: 1.96-5.13) and camels (aOR: 9.75; 95% CI: 6.02-15.78). Significant differences in seropositivity were also found between domains (Western Desert, Eastern Desert and Nile Valley and Delta) and 25 governorates (p < 0.001), respectively. Animal rearing in the Eastern Desert domain was found to be a significant risk factor (aOR: 2.16; 95% CI: 1.62-2.88). Most seropositive animals were older than four years. No correlation between positive titers and husbandry practices or animal origin were found (p > 0.05). Only 8.7% of the interviewed people living on the farms consumed raw camel milk and none reported prior knowledge on Q fever. Findings from this nationwide study show that exposure to Coxiella burnetii is common in ruminants and camels. Disease awareness among physicians, veterinarians and animal owners has to be raised. Future epidemiological investigations have to elucidate the impact of Q fever on human health and on the economy of Egypt.

Preharvest Food Safety Challenges in Beef and Dairy Production

Foods of animal origin, including beef and dairy products, are nutritious and important to global food security. However, there are important risks to human health from hazards that are introduced to beef and dairy products on the farm. Food safety hazards may be chemical, biological, or physical in nature. Considerations about protecting the safety of beef and dairy products must begin prior to harvest because some potential food safety hazards introduced at the farm (e.g., chemical residues) cannot be mitigated by subsequent postharvest food processing steps. Also, some people have preferences for consuming food that has not been through postharvest processing even though those foods may be unsafe because of microbiological hazards originating from the farm. Because of human fallibility and complex microbial ecologies, many of the preharvest hazards associated with beef and dairy products cannot entirely be eliminated, but the risk for most can be reduced through systematic interventions taken on the farm. Beef and dairy farms differ widely in production practices because of differences in natural, human, and capital resources. Therefore, the actions necessary to minimize on-farm food safety hazards must be farm-specific and they must address scientific, political, economic, and practical aspects. Notable successes in controlling and preventing on-farm hazards to food safety have occurred through a combination of voluntary and regulatory efforts.

[Effects of vaccination against Q-fever in Lower Saxony dairy cattle farms]

OBJECTIVE

Being a notifiable and zoonotic disease, Q-fever is coming under increasing focus of epizootic disease control. Current studies indicate that the disease is more widespread in Germany than the number of notifications suggest. Therefore, since 2013, under certain conditions a hardship allowance is granted by the Animal Diseases Fund of Lower Saxony for the vaccine costs of the basic immunization to support affected farms. Material und methods: All farmers, on whose farms clinical signs of Q-fever and the pathogen Coxiella burnetii had been detected prior to vaccination and who had taken advantage of the hardship allowance during the previous 2 years were surveyed to assess the effectiveness of the measure. The survey was conducted by telephone using a previously compiled questionnaire. The topics included the observed clinical signs in cattle before and after the vaccination and the evaluation of the vaccination.

RESULTS

Clinical manifestations indicating a Q-fever infection may differ widely and include aborts and fertility disorders and/or frequently occurring inflammations (pneumonia, mastitis, metritis) and/or unspecific symptoms presenting as higher susceptibility to disease, weakness, and fever attacks. Following vaccination, the vast majority of the farmers (84 %) observed a marked health improvement in their cattle and two thirds of the respondents intend to continue with the vaccination even without financial support from the Animal Diseases Fund. Adverse effects beyond general vaccination reactions, including transiently elevated body temperature, physical weakness and fluctuations in milk performance, were rarely observed.

CONCLUSIONS AND CLINICAL RELEVANCE

The clinical signs for Q-fever were diverse and often unspecific. According to the assessments by the farmers, clinical problems in most cases were considerably reduced following Q-fever vaccination. Vaccination appears to be a valuable tool in the control of this zoonosis.

Effect of a phase I Coxiella burnetii inactivated vaccine on body temperature and milk yield in dairy cows

Q fever is a zoonotic disease caused by Coxiella burnetii. The pathogen is prevalent in ruminants (goats, sheep, cows), which are the main sources of human infection. In the cattle industry around the world, animal (15 to 20%) and herd (38 to 72%) level prevalences of C. burnetii are high. Vaccination of ruminants against Q fever is considered important to prevent spreading of the disease and risk of infection in humans. However, published information on side effects of the Q fever vaccination under field conditions is limited for cows. The objective of this study was to investigate the effect of the phase I C. burnetii inactivated vaccine Coxevac on body temperature and milk yield in dairy cows. In 2 experiments, a total of 508 cows were randomly divided into 2 groups to determine the effect of first vaccination on body temperature and milk yield. The C. burnetii serostatus of all cows was tested before vaccination with an indirect ELISA. The first experiment took place in the teaching and research barn of the Clinic of Animal Reproduction at the Freie Universität Berlin. Temperature was measured vaginally in 10 cows in a crossover design. The second experiment was conducted on a commercial dairy farm. Milk yield of 498 cows was measured 1 wk before and 1 wk after vaccination. In a subset of 41 cows, temperature was measured rectally. In both experiments, body temperature increased significantly after vaccination (1.0 ± 0.9°C and 0.7 ± 0.8°C). A significant difference was also found in body temperature between vaccinated and control cows. Thirty percent of the vaccinated animals in experiment 1 showed reversible swelling at the injection site as a reaction to the vaccination. The results indicate that vaccination against Q fever causes a transient increase of body temperature that peaks in the first 12 to 24h and declines after that. In experiment 2, vaccinated cows (26.8 ± 0.39 kg/d) produced significantly less milk than did control cows (28.2 ± 0.44 kg/d) 7d after first vaccination. The cumulative milk loss after first vaccination was influenced by an interaction between C. burnetii serostatus and average milk yield 7d before first vaccination. This was considered as part of the physiological immune response. Three out of 10 vaccinated animals in experiment 1 showed painful swelling of the skin at the injection site, which had a maximum size of 14.0 × 14.0 × 1.1cm. In conclusion, a transient increase of body temperature and a decrease in milk yield is prevalent after Coxevac vaccination.

Scientific opinion on an alternative method for the hygienic treatment of bovine colostrum through a series of filtration steps

An alternative method to the HTST treatment (High Temperature Short Time pasteurisation at 72 °C for at least 15 seconds or equivalent pasteurisation effect achieving a negative reaction to a phosphatase test), approved for the treatment of bovine colostrum (Category 3 material), was assessed. The purpose of the alternative method, based on a series of filtration steps, is the production of Colostrinov, a product whose main ingredient is bovine colostrum, to be used for foal nutrition. Since the filtration techniques used are known to eliminate particles of the size of bacteria, fungi and protozoa from liquids, it is reasonable to assume that the microfiltration process reduces these contaminants to a level at least equivalent to the treatment required by the legislation. Owing to their small size, viruses are not retained by the mechanical effect of the filters but they may be retained by physico-chemical interactions with the surface of the filter, depending on the surface properties of the viruses and those of the filter, as well as on the properties of the surrounding liquid. From the information provided by the applicant, it cannot be concluded whether or not the microfiltration process reduces the relevant viral contaminants to a level at least equivalent to a single HTST treatment as required by the legislation.

Does Coxiella burnetii affect reproduction in cattle? A clinical update

Q fever is a zoonosis produced by Coxiella burnetii, a bacterium that is widely distributed worldwide. Domestic ruminants are the most important source of C. burnetii for human infection. In sheep and goats, abortion is the main clinical consequence of infection, yet the symptoms described in cattle have so far been inconsistent. Q fever has been also scarcely reported in cattle, most likely because of its difficult diagnosis at the farm level and because of the many existing responsible C. burnetii strains. In this report, the effects of C. burnetii infection or Q fever disease on the reproductive behaviour of dairy cattle are reviewed, with special emphasis placed on the scarcity of data available and possible control actions discussed.

Coxiella burnetii associated reproductive disorders in domestic animals--a critical review

The bacterium Coxiella burnetii has been detected in the fetal membranes, birth fluids and vaginal mucus, as well as in the milk and other excretions of several domestic mammals. The finding of C. burnetii in association with abortion, parturition and in the postpartum period has led to the hypothesis that C. burnetii causes a range of reproductive diseases. This review critically evaluates the scientific basis for this hypothesis in domestic mammals.The review demonstrates a solid evidence for the association between C. burnetii infection and sporadic cases of abortion, premature delivery, stillbirth and weak offspring in cattle, sheep and goats. C. burnetii induced in-herd epidemics of this complete expression of reproductive failure have been reported for sheep and goats, but not for cattle. The single entities occur only as part of the complex and not as single events such as generally increased stillbirth rate. Studies show that C. burnetii initially infects the placenta and that subsequent spread to the fetus may occur either haematogenous or by the amniotic-oral route. The consequences for the equine, porcine, canine and feline conceptus remains to the elucidated but that infection of the conceptus may occur is documented for most species. There is no solid evidence to support a hypothesis of C. burnetii causing disorders such as subfertility, endometritis/metritis, or retained fetal membranes in any kind of domestic animal species.There is a strong need to validate non-pathology based methods such as polymerase chain reaction for their use in diagnostic and research in relation to establishing C. burnetii as the cause of abortion and to adapt an appropriate study design and include adequate control animals when linking epidemiological findings to C. burnetii or when evaluating effects of vaccination in production herds.

Molecular typing of Coxiella burnetii (Q fever)

Although we live in the age of genomics and the availability of complete genome sequences of Coxiella burnetii has increased our understanding of the genomic diversity of the agent, it is still somewhat a "query" microorganism. The epidemiology of Q fever is complex due to the worldwide distribution, reservoir and vector diversity, and a lack of studies defining the dynamic interaction between these factors. In addition Coxiella is an agent that could be used as a bioterror weapon. Therefore, typing methods that can discriminate strains and be used to trace back infections to their source are of paramount importance. In this chapter we provide an overview of historical and current typing methods and describe their advantages and limitations. Recently developed techniques such as MLVA and SNP typing have shown promise and improved the discrimination capacity and utility of genotyping methods for molecular epidemiologic studies of this challenging pathogen.

Serological screening for Coxiella burnetii infection and related reproductive performance in high producing dairy cows

The possible relationship between Coxiella-seropositivity and the reproductive performance of cows during the previous year to the serological screening was examined in three high producing dairy herds. The herds had a history of subfertility (<25% of pregnancies for the total number of AI), abortion (>18% abortions) and a positive polymerase chain reaction test for Coxiella burnetii in the bulk tank milk with an excretion higher than 10(4)Coxiella /ml for all three herds. Antibodies against C. burnetii were detected in 50.2% of the 781 parous cows analyzed. Coxiella seropositivity was linked to placenta retention, to changes in the interval from parturition to conception (with the lowest interval parturition-conception for cows with low level of seropositivity), early pregnancy (cows becoming pregnant before Day 90 postpartum) and maintenance of gestation during the early fetal period, while it failed to affect rates of abortion after Day 90 of gestation or stillbirth.

Coxiella burnetii (Q fever) seroprevalence in cattle

Human cases of Q fever appear to be common in Northern Ireland compared to the rest of the British Isles. The purpose of this study was to describe the seroepidemiology of Coxiella burnetii infection in cattle in Northern Ireland in terms of seroprevalence and determinants of infection. A total of 5182 animals (from a stratified systematic random sample of 273 herds) were tested with a commercial C. burnetii phase 2 IgG ELISA. A total of 6.2% of animals and 48.4% of herds tested positively. Results from a multilevel logistic regression model indicated that the odds of cattle being infected with Q fever increased with age, Friesian breed, being from large herds and from dairy herds. Large dairy herd animal prevalence was 12.5% compared to 2.1% for small beef herds. Preliminary seroprevalence in sheep (12.3%), goats (9.3%), pigs (0%) rats (9.7%) and mice (3.2%) using indirect immunofluorescence is reported.

Changing trends in mastitis

The global dairy industry, the predominant pathogens causing mastitis, our understanding of mastitis pathogens and the host response to intramammary infection are changing rapidly. This paper aims to discuss changes in each of these aspects. Globalisation, energy demands, human population growth and climate change all affect the dairy industry. In many western countries, control programs for contagious mastitis have been in place for decades, resulting in a decrease in occurrence of Streptococcus agalactiae and Staphylococcus aureus mastitis and an increase in the relative impact of Streptococcus uberis and Escherichia coli mastitis. In some countries, Klebsiella spp. or Streptococcus dysgalactiae are appearing as important causes of mastitis. Differences between countries in legislation, veterinary and laboratory services and farmers' management practices affect the distribution and impact of mastitis pathogens. For pathogens that have traditionally been categorised as contagious, strain adaptation to human and bovine hosts has been recognised. For pathogens that are often categorised as environmental, strains causing transient and chronic infections are distinguished. The genetic basis underlying host adaptation and mechanisms of infection is being unravelled. Genomic information on pathogens and their hosts and improved knowledge of the host's innate and acquired immune responses to intramammary infections provide opportunities to expand our understanding of bovine mastitis. These developments will undoubtedly contribute to novel approaches to mastitis diagnostics and control.