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1.
Q fever is a zoonosis caused by the obligate intracellular bacterium, Coxiella burnetii. Aborting domestic ruminants are the main source of human infection. In January 2003, an abortion episode occurred in a dairy caprine herd where 18/60 (30%) goats experienced reproductive problems: 4/60 (7%) aborted and 14/60 (23%) had stillbirths. Serological screening for abortion-related infectious diseases suggested Q fever. The diagnosis of C. burnetii infection was confirmed with PCR based on the occurrence of C. burnetii shedding into vaginal mucus, faeces and colostrums taken after kidding from the affected animals. The pregnancy following this episode resulted in one abortion and four stillbirths; three of those goats had already experienced reproductive failure during the previous kidding season. The seroprevalence of C. burnetii infection and the bacteria shedding were investigated using both ELISA and PCR assays, respectively, during the course of the initial and subsequent kidding seasons. Serological testing, performed on the whole herd 6 weeks after the abortion episode, showed 48/60 (80%) of ELISA positive goats. PCR assay performed on both vaginal swab and milk samples showed that the bacterium was shed for almost four months after the outbreak. C. burnetii DNA was also amplified from vaginal swab and milk samples taken from goats after the second kidding season. Furthermore, the bacteria were found into 14 vaginal swabs and 12 milk samples taken from infected females at both kidding seasons.  相似文献   

2.
In 290 Q fever positive cattle from three 2000 head dairy farms in the former district of Erfurt (Thüringen) the course of titers was examined serologically over several months by means of the complement fixation test (CFT). In 47.2% of the cows serologically observed for 2 up to 28 months complement fixing antibodies against Coxiella burnetii could be demonstrated til the end of the investigation period. Repeated tests during pregnancy showed increase of antibody titers in the first 4 months and after a short decrease again from the 5. til the 7. month. By observing the antibody titers during several pregnancies each time a new increase comparable to a booster immunisation could be found. This may explain the persistence of Q fever antibodies in cows for several years. The results of this investigation suggest that from a high antibody titer it can not be concluded an abortion in a positive cow being caused by a Coxiella burnetii infection.  相似文献   

3.
Enzyme immunoassay for surveillance of Q fever   总被引：4，自引：0，他引：4  
An enzyme-linked immunosorbent assay (ELISA) was developed to monitor antibodies against Coxiella burnetii among animal populations used in research and teaching facilities. Various antigenic components of C burnetii prepared from phase I and phase II whole cells and commercially available antigens were evaluated. A trichloroacetic acid extract was selected for routine use. There was a linear relationship between the transformed absorbance readings of the ELISA results and microagglutination (MA) titers. Comparison between positive or negative results of the MA test and ELISA gave 98.6% concordance. Using the MA test as the standard, ELISA results were 97.8% sensitive and 100% specific. The efficacy of ELISA was evaluated by testing ruminants with known histories of C burnetii infection. Antibody prevalence was 0 in 117 sheep with no history of C burnetii infection, 22% in 145 naturally infected sheep used for research, and 53% in 115 sheep used for vaccine field trials. Forty-eight percent of 120 dairy cows and 52% of 79 goats from endemically infected herds were seropositive. These results indicate that ELISA should be the test of choice for mass screening and surveillance of animals when Q fever is a suspected biohazard.  相似文献   

4.
Coxiella burnetii, an obligate intracellular parasite with a worldwide distribution, is the causative agent of acute and chronic Q fever in humans. Although infection is often unapparent in cattle, sheep and goats, there is increasing evidence that C. burnetii infection in these species is associated with abortion and stillbirth. This paper describes the introduction of a single-tube nested PCR protocol for the diagnosis of C. burnetii-related abortion in domestic ruminants in Italy. A total of 514 aborted foetuses from cattle (n = 138) and sheep and goat (n = 376), collected from 301 farms, were analyzed from January 2001 to March 2005. Ninety-seven of 514 (18.9%) animals tested PCR-positive, with 16/138 (11.6%) cattle and 81/376 (21.5%) sheep and goat. Eleven of 102 (10.8%) farms with reproductive disorders in cattle and 37/199 (18.6%) farms with reproductive disorders in sheep and goats were infected with C. burnetii. A greater incidence was observed in three of the seven investigated provinces (p < 0.01), with rates of infected farms of up to 23.8%. Data showed that almost all the C. burnetii-related abortions were recorded between October and April (p < 0.01). These findings suggest that Q fever in humans is largely underestimated in Italy, probably because its occurrence is obscured by flu-like symptoms in acute forms.  相似文献   

5.
Between 1999 and 2002, 9349 sera and 517 aborted samples (422 foetuses and 95 placenta) were analysed from 675 sheep and 82 goat farms distributed all over the island of Sardinia. After abortion notification, sera collected at random from adult animals were examined to detect antibodies specific to Coxiella burnetii by ELISA, whereas foetuses and placenta were analysed by PCR assay. Specific IgG antibodies were detected in 255 (38%) sheep farms and in 39 (47%) goat herds whereas 40 ovine (10%) and 3 (6%) caprine foetuses were C. burnetii PCR-positive. Although C. burnetii DNA was amplified from different types of tissues, placenta was the tissue with the highest detection rate. Seroprevalence analysis indicates that C. burnetii distribution in sheep and goats is very high, but PCR results demonstrate that C. burnetii has a relatively low role in abortion, especially in goats.  相似文献   

6.
Numerous data show that the epizootics of Q fever in goats can be particularly related to cases of this disease in humans. The aim of the study was to examine 98 goat serum samples from the farm where abortions, early parturition and parturition of weak goatlings were noted. The microaglutination method was used in this study. Serum dilution 1:8 was defined as a positive titre. The study revealed that 79.6% of serum samples were positive and numerous high titres suggested an acute form of infection. It could be supposed that Q fever was the reason of abortions in the herd. The results obtained point to the necessity of examinations for Q fever in goats, because of the possibility of infection in people who have a contact with these animals. Goats seem to be the animal species especially sensitive to C. burnetii infection. Q fever should be taken into consideration in the differential diagnosis of the goat diseases, when abortions occur.  相似文献   

7.
Q fever is a widespread zoonosis caused by Coxiella burnetii. Infected animals, shedding bacteria by different routes, constitute contamination sources for humans and the environment. To study Coxiella excretion, pregnant goats were inoculated by the subcutaneous route in a site localized just in front of the shoulder at 90 days of gestation with 3 doses of bacteria (10(8), 10(6) or 10(4) i.d.). All the goats aborted whatever the dose used. Coxiella were found by PCR and immunofluorescence tests in all placentas and in several organs of at least one fetus per goat. At abortion, all the goats excreted bacteria in vaginal discharges up to 14 days and in milk samples up to 52 days. A few goats excreted Coxiella in their feces before abortion, and all goats, excreted bacteria in their feces after abortion. Antibody titers against Coxiella increased from 21 days post inoculation to the end of the experiment. For a Q fever diagnostic, detection by PCR and immunofluorescence tests of Coxiella in parturition products and vaginal secretions at abortion should be preferred to serological tests.  相似文献   

8.
Coxiella burnetii, the causative agent of Q fever, is an obligatory intracellular bacterium with worldwide distribution. The aim of this study was to determine the prevalence of C. burnetii phase II antibodies in two different groups (high and low risk) of healthy human population and investigate the epidemiological characteristics of the infection in the island of Crete (southern Greece). Collection and testing by IFA of 493 sample sera for IgG and IgM antibodies against C. bumetii phase II antigen indicated a prevalence of IgG antibodies of 48.7%. Of the seropositive individuals, 34% also revealed IgM seropositive antibody titers. Analysis of 225 sample sera by IFA from high risk population presented a prevalence for C. burnetii of 62.2%. Our findings revealed that C. burnetii is highly endemic in Crete, indicating a high exposure of the population to the pathogen regardless of occupation or place of residence.  相似文献   

9.
To describe both shedding and serological patterns following abortions detected as being associated with Coxiella burnetii (Cb), 24 cows experiencing an abortion due to Cb were followed over a one month period. Samples taken on the day of abortion (D0) were followed 3-fold by weekly samplings from day 14 (D14) to D28 after the abortion. Milk and vaginal mucus were collected at each weekly sampling and tested using real-time PCR while blood samples were collected 2-fold on D21 and D28 and tested using ELISA. We found a very short duration of C. burnetii shedding in vaginal mucus after abortion, highlighting the need to collect samples as rapidly as possible following an abortion to avoid false negative results. In contrast with previous results, concomitancy of vaginal and mucus shedding was frequent, especially for cows shedding a high bacterial load on DO leading to the hypothesis that the clinical onset of the infection influences the modalities of Cb shedding. Lastly, serological results indicating a lack of sensitivity to detect Cb shedder cows (especially for cows for which Ct values were high) suggest that ELISA is not a useful tool to diagnose abortions at the individual level.  相似文献   

10.
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.  相似文献   

11.
The intracellular bacteria Coxiella (C) burnetii and Chlamydia (Chl) abortus induce abortion in sheep and also affect humans. While Chl. abortus only infrequently infects humans, C burnetii is the aetiological agent of numerous Q fever outbreaks during the last decades. There is only limited knowledge about the prevalence of both pathogens in sheep, although sheep are involved in almost all Q fever outbreaks in Germany. The aim of our study was to investigate the prevalence of both pathogens in flocks located in Lower Saxony, Germany, in correlation to the management form and abortion rate. Serum samples of 1714 sheep from 95 flocks located in Lower Saxony were investigated by ELISA. 2.7% of these samples were positive, 1.3% showed inconclusive results in the C. burnetii-ELISA. Elevated intra-flock seroprevalences were only detected in three migrating flocks. Chlamydia-specific antibodies could be detected in 15.1% serum samples of mainly shepherded and migrating flocks. In one of these flocks with a high intra-flock seroprevalence for C burnetii (27%) and Chlamydia (44.9%), C burnetii was detected in 21.6% of the placenta samples of normal births and in 12.5% of the colostrum samples by PCR. Aborted fetuses and the corresponding placentas were negative in C burnetii-PCR, but in most of them and also in many other placenta samples Chl. abortus could be detected by PCR and DNA microarray. This survey shows a low overall prevalence of C. burnetii in sheep in Lower Saxony in the year 2004. However, three migrating flocks with a high intra-flock prevalence are localized in the southern parts of Lower Saxony. Spreading of C burnetii could occur, because of the large radius of grazing of all three flocks.  相似文献   

12.
Coxiella burnetii is an intracellular bacterium that causes a worldwide zoonosis, the Q fever. Currently, to diagnose the infection in ruminants, whole cell antigens-based ELISAs are used. In this study a heat shock protein, the HspB, was evaluated for its ability to be recognized by the goat immune system and its capacity to sign a stage of infection. The htpB gene of C. burnetii was cloned and sequenced. A high identity (>90%) was observed among the htpB genes of four ruminant strains tested. A recombinant protein was expressed in a prokaryotic expression system. The rHspB protein was used to determine the IgG reactivity by ELISA. Sera from experimentally and naturally infected goats were tested. The rHspB is recognized early during the infection course, at 18 days post-infection. Moreover, 80-90% of the animals tested were positive at 39-60dpi. In addition, animals presenting a reactivation of the infection displayed a higher reactivity, statistically significant (p<0.05), than that of the animals in latent infection. These findings suggest that the rHspB could be a good candidate for the development of an ELISA test making possible the detection of recent C. burnetii infection in goats as well as reactivation in those with latent infection.  相似文献   

13.
Q or “query” fever is a zoonosis caused by the organism Coxiella burnetii. Cattle, sheep and goats are the most common reservoirs of this organism. The placenta of infected animals contains high numbers (up to 109/g) of C. burnetii. Aerosols occur at the time of parturition and man becomes infected following inhalation of the microorganism. The spectrum of illness in man is wide and consists of acute and chronic forms. Acute Q fever is most often a self-limited flu-like illness but may include pneumonia, hepatitis, or meningoencephalitis. Chronic Q fever almost always means endocarditis and rarely osteomyelitis. Chronic Q fever is not known to occur in animals other than man. An increased abortion and stillbirth rate are seen in infected domestic ungulates.

Four provinces (Nova Scotia, New Brunswick, Ontario and Alberta) reported cases of Q fever in 1989.

A vaccine for Q fever has recently been licensed in Australia.

  相似文献   

14.
This study examined the occurrence of Coxiella burnetii (C. burnetii), the infectious agent of Q-fever, in sheep and sheep-ticks in Baden-Wuerttemberg, Germany, as a possible source of infection in Q-fever outbreaks. Using PCR, we examined a total of 1066 Dermacentor ticks from 23 herds and 49 samples of tick excrement from 18 herds for C. burnetii. We found the infectious agent in one non-engorged tick and in one sample of tick excrement from the same herd, in Efringen-Kirchen (district Loerrach). Sequencing the PCR-products confirmed the amplifications as specific for C. burnetii. Further serological tests of random samples of the four districts of Baden-Wuerttemberg showed a seroprevalence from 0 to 1.4% using complement fixation test (CFT), as well as a 0.9 to 10.2% seroprevalence, using ELISA test. Serum samples from a Q-fever-suspicious herd resulted, however, in 6% (CFT) and 53% (ELISA) positive reactions. A comparison between CFT and ELISA showed both a correlation of the two test methods that increased with higher CFT titration levels and positive reactions using ELISA for 9.4% of the serums that had tested negative using CFT. The results of the present study reveal that ticks and their excrements are important vectors of transmission of Q-fever in Baden-Wuerttemberg. Investigations on C. burnetii using PCR as well as serological surveys of sheep are important instruments for diagnosis and disease control of Q-fever.  相似文献   

15.
本研究以Q热贝氏柯克斯体弱毒株Ⅱ相全菌为包被抗原建立Q热贝氏柯克斯体间接ELISA检测方法,通过方阵滴定法对抗原包被浓度和二抗反应浓度的确定及各项反应条件的优化,确定其阴阳性临界值为0.44。用本方法与IDEXX Q热抗体检测试剂盒对393份牛临床血清进行检测,检出的血清阳性率分别为11.45%和6.10%,符合率为94.66%。结果表明,本试验建立的检测Q热贝氏柯克斯体的间接ELISA法具有较好的特异性及较强的敏感性,可初步应用于Q热贝氏柯克斯体抗体的临床检测。  相似文献   

16.
In 2007, a human Q fever epidemic started, mainly in the south eastern part of The Netherlands with a suspected indirect relation to dairy goats, and, to a lesser degree, to dairy sheep. This article describes the Q fever prevalences in Dutch dairy goat and dairy sheep bulk tank milk (BTM) samples, using a real-time (RT) PCR and ELISA. Results of BTM PCR and ELISA were compared with the serological status of individual animals, and correlations with a history of Q fever abortion were determined. When compared with ELISA results, the optimal cut-off value for the RT-PCR was 100 bacteria/ml. In 2008, there were 392 farms with more than 200 dairy goats, of which 292 submitted a BTM sample. Of these samples, 96 (32.9 per cent) were PCR positive and 87 (29.8 per cent) were ELISA positive. All farms with a history of Q fever abortion (n=17) were ELISA positive, 16 out of 17 were also PCR positive. BTM PCR or ELISA positive farms had significantly higher within-herd seroprevalences than BTM negative farms. In the south eastern provinces, the area where the human Q fever outbreak started in 2007, a significantly larger proportion of the BTM samples was PCR and ELISA positive compared to the rest of The Netherlands. None of the BTM samples from dairy sheep farms (n=16) were PCR positive but three of these farms were ELISA positive. The higher percentage of BTM positive farms in the area where the human Q fever outbreak started, supports the suspected relation between human cases and infected dairy goat farms.  相似文献   

17.
The objective of this study was to evaluate the performance of the complement fixation test (CFT) with respect to ELISA for the serological diagnosis of Q fever and to assess the role of serology as a tool for the identification of the shedder status. During 2009-2010, sera from 9635 bovines and 3872 small ruminants (3057 goats and 815 sheep) were collected and analyzed with CFT and ELISA. In addition, 2256 bovine, 139 caprine and 72 ovine samples (individual and bulk tank milk samples, fetuses, vaginal swabs and placentae) were analyzed with a real-time PCR kit. The relative sensitivity (Se) and specificity (Sp) of CFT with respect to ELISA were Se 26.56% and Sp 99.71% for cattle and Se 9.96% and Sp 99.94% for small ruminants. To evaluate the correlation between serum-positive status and shedder status, the ELISA, CFT and real-time PCR results were compared. Due to the sampling method and the data storage system, the analysis of individual associations between the serological and molecular tests was possible only for some of the bovine samples. From a statistical point of view, no agreement was observed between the serological and molecular results obtained for fetus and vaginal swab samples. Slightly better agreement was observed between the serological and molecular results obtained for the individual milk samples and between the serological (at least one positive in the examined group) and molecular results for the bulk tank milk (BTM) samples. The CFT results exhibited a better correlation with the shedder status than did the ELISA results.  相似文献   

18.
Using PCR on aborted foetal material, Coxiella burnetii infection was confirmed as the cause of abortions in a dairy goat herd with over 1000 adults. Ninety-five (22%) abortions and 355 normal births were recorded from 440 goats over 2months. The herd was sampled three times in 6months to look at the within-herd seroprevalence, with the 1st visit done 24days after the last recorded abortion. The true seroprevalence in the herd was 79.2%, 66.5% and 45.7% on each of these visits, but introduction of a group of young goats prior to the 3d visit influenced these results. Using PCR, widespread environmental contamination was demonstrated in surface dust, bedding, muck heaps, milk, bird droppings and drinking water in the goat shed. MST and MLVA analysis showed the C. burnetii from this outbreak to be of a genotype previously observed in the UK and different from those recorded in the Netherlands outbreak of 2007-2011.  相似文献   

19.
A real-time PCR was developed to detect Coxiella burnetii (the cause of Q fever) in ruminant placentas and aborted fetuses. Primer and probe sets previously developed for human tissue studies were used to target the insertion sequence IS1111 gene for C burnetii. The assay was highly sensitive, with a limit of detection of 10 copies of template, theoretically equating to a single bacterium, and did not cross-react with a panel of other bacteria. To determine sensitivity on field samples submitted for the diagnosis of abortion, results using the IS1111 PCR assay were compared with a com1 PCR assay. When applied to ruminant abortion material, including placental cotyledons and fetal samples, the IS1111 and com1 assays yielded positive results in 23 (25 per cent) of 93 and 19 (20 per cent) of 93 samples, respectively. One infected goat herd was monitored for 31 months: 57 (92 per cent) of 62 placental cotyledon samples from aborting and non-aborting goats, and 10 (30 per cent) of 33 fetal samples were positive by the IS1111 PCR assay.  相似文献   

20.
In order to evaluate suitability of Fluorescence Polarisation Assay (FPA) for serological Brucella diagnostic, 1739 samples of sera from cattle, pigs, sheep and goats (65 Brucella-positive, 960-negative and 714 false-positive sera) were investigated at a dilution of 1:10. The cut-off was adjusted by means of ROC analysis. Furthermore, the serum samples were examined for Brucella antibodies using SAT, CFT and ELISA and the results were evaluated regarding sensitivity and specificity. FPA, SAT, CFT and ELISA attained a sensitivity of 92.3, 98.5, 84.6 and 86.2%. In comparison, specificity varied with 87.8, 72.6, 92.5 and 85.8%, respectively. Accordingly, FPA is a suitable test for serodiagnosis of brucellosis.  相似文献   

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