Q fever prevention and vaccination

The simpliest way how to avoid the development and spreading of any infection, including Q fever in extenso, is prevention. The main principles of prevention are: educate the public on sources of infection, appropriately dispose of placenta, birth products, fetal membranes, and aborted fetuses at facilities housing sheep and goats, restrict access to barns and laboratories used in housing potentially infected animals, use only pasteurized milk and milk products, use appropriate procedures for bagging, autoclaving, and washing of laboratory clothing, quarantine imported animals, periodical monitoring of seroprevalence in cattle, sheeps and goats, vaccination of the risk groups etc. Four different basic types of Q fever vaccines have been developed: 1) live attenuated vaccines were derived from the Coxiella burnetii strain Grita in phase I of a highly reduced virulence but preserved immunogenicity, 2) highly purified corpuscular formalin-inactivated vaccine derived from the C. burnetii Henzerling strain in phase I, 3) a soluble vaccine prepared from the C. burnetii strain Nine Mile corpuscules in phase I by extraction with trichloracetic acid, and 4) in the USA, the use of a chloroform-methanol extraction residue subunit vaccine of C. burnetii strain Nine Mile in phase I of a low reactogenicity has been recommended.     

Outbreak of Q fever associated with a horse-boarding ranch, Colorado, 2005

Coxiella burnetii is a bacterium located worldwide that can cause Q fever when inhaled. We describe an outbreak of Q fever associated with a horse-boarding ranch that had acquired two herds of goats. We conducted case finding and cohort studies among persons who boarded horses on the ranch and ranchers and among residents in the surrounding community, and conducted sampling of the goats and environment, to determine risk factors for infection and guide public health interventions. Sixty-six ranchers and persons who boarded horses on the ranch were interviewed; 62 (94%) were not professional ranchers. Twenty persons (53%) of 38 persons tested had evidence of infection with C. burnetii. Contact with goats was associated with seropositivity, including having helped birth goats (relative risk [RR] 2.4, 95% confidence interval [CI] 1.6-3.6), having had contact with newborn goats (RR 2.3, CI 1.2-4.3), having vaccinated goats (RR 2.1, CI 1.3-3.5), having had contact with stillbirths or newborns that died (RR 2.1, CI 1.2-3.7), and having fed goats (RR 2.1, CI 1.0-4.3). Among 138 tested persons living within 1 mile of the ranch, 11 (8%) demonstrated evidence of C. burnetii infection; eight seropositive persons (73%) had no direct contact with the ranch. Testing of the soil and goats with an IS1111 polymerase chain reaction (PCR) assay confirmed the presence of C. burnetii among the herd and in the environment. This outbreak of Q fever was caused by exposure to infected goats, but exposure to the environment likely played a secondary role. Laypersons should not participate in the birthing process of goats; professionals who come into contact with birthing goats should be educated on reducing their infection risk. This is the first time an IS1111 PCR assay has been used in an outbreak investigation in the United States.     

Outbreak of Q fever in Lohra-Rollshausen,Germany, spring 1996

Q fever is an acute (and sometimes chronic) febrile illness caused by the rickettsial organism Coxiella burnetii. The commonest animal reservoirs for C. burnetiiare cattle, sheep, and goats. Infected animals shed the organisms, which resist desiccation, i     

Pigeon pneumonia in provence: a bird-borne Q fever outbreak.

Q fever is a widespread zoonosis caused by Coxiella burnetii, an obligate intracellular bacterium, which humans usually acquire through the inhalation of infected dust from subclinically infected mammals. Human infection commonly takes place when an infected mammal gives birth, since high concentrations of the organism are found in the products of conception. Worldwide, cattle, sheep, and goats are the most common reservoirs for C. burnetii. A few investigators have also reported parturient cats and dogs as the sources of human outbreaks of Q fever. During a 10-day period in May 1996, all five members of one family living on a farm in Provence, in the south of France, became ill with fever, general malaise, and cough. All of them had acute Q fever. An epidemiological investigation suggested that this outbreak resulted from exposure to contaminated pigeon feces and ticks.     

Natural history of Q fever in goats

During the spring of 1999, an outbreak of Q fever resulted in 30 abortions among 174 (17%) goats in a caprine cooperative in Newfoundland. The intent of this study was to determine the natural history of Coxiella burnetii infection in goats. Twenty-four goats on one farm were followed through the next two kidding seasons following the Q fever outbreak. Antibodies to phases I and II C. burnetii were determined using an indirect immunofluorescence assay and samples of placentas were cultured for C. burnetii and polymerase chain reaction was used to identify C. burnetii DNA. Phase I antibody was present in high levels and was maintained over the study period, while phase II antibody levels declined to the seronegative range in 60% of the infected goats. Molecular studies suggest that excretion of C. burnetii in the placenta of infected goats seems to be limited to the next kidding season following an outbreak. We therefore conclude that C. burnetii infection in goats seems to be limited to two kidding seasons. Phase I antibody levels are maintained, while phase II antibody levels decline.     

Coxiella burnetii seroprevalence of shepherds and their flocks in the lower Saint-Lawrence River region of Quebec, Canada.

OBJECTIVE: To determine the seroprevalence of Coxiella burnetii among the shepherds and their sheep in the lower Saint-Lawrence River region (LSLRR) of Quebec, Canada. DESIGN: A prospective human-animal comparative study was conducted with 81 shepherds from 46 farms and a control group matched for sex and age. All participants answered a standardized questionnaire to evaluate their risk factors for Q fever, including a specific section on the work practices of the shepherds. All human subjects had a blood sample taken for serology to phase I and phase II antigens of C burnetii performed by indirect immunofluorescence assay. At each participating farm, seven to nine sheep had blood samples taken for C burnetii serology to be assessed by the complement fixation test. RESULTS: The seroprevalence to C burnetii was higher in the group of shepherds (28.4%) than the control group (1.2%) (P<0.005). Among the group of shepherds, spending more than 5 h/week in the sheep barn (P=0.06) and buying and/or trading sheep within the past six months (P=0.004) were associated with positive C burnetii serology. A total of 137 of 334 sheep (41%) were seropositive for C burnetii. These positive sheep were distributed in 41 of the 46 flocks (89%). No correlation could be demonstrated between a serology for C burnetii in the herds and the shepherds. CONCLUSION: Q fever is highly prevalent in the LSLRR of Quebec, affecting 89% of the flocks and 28% of the shepherds. Shepherds in this region are at increased risk for C burnetii infection in comparison to the general population.     

Q Fever in the United States: Summary of Case Reports from Two National Surveillance Systems, 2000–2012

Q fever is a worldwide zoonosis historically associated with exposure to infected livestock. This study summarizes cases of Q fever, a notifiable disease in the United States, reported to the Centers for Disease Control and Prevention through two national surveillance systems with onset during 2000–2012. The overall incidence rate during this time was 0.38 cases per million persons per year. The reported case fatality rate was 2.0%, and the reported hospitalization rate was 62%. Most cases (61%) did not report exposure to cattle, goats, or sheep, suggesting that clinicians should consider Q fever even in the absence of livestock exposure. The prevalence of drinking raw milk among reported cases of Q fever (8.4%) was more than twice the national prevalence for the practice. Passive surveillance systems for Q fever are likely impacted by underreporting and underdiagnosis because of the nonspecific presentation of Q fever.     

Coxiella burnetii, the agent of Q fever, in domestic sheep flocks from Wyoming, United States

Coxiella burnetii, the agent of Q fever, is an intracellular bacterial pathogen. It has a nearly cosmopolitan distribution. We conducted a serological survey of domestic sheep herds for infections with C. burnetii in Wyoming following reports of abortion and open ewes. Based on the serologic evidence, there was no link between reproductive problems and exposure to C. burnetii. However, the overall prevalence of C. burnetii in WY sheep was 7%, which indicates that the agent is present in the environment and could pose a threat to public health.     

An outbreak of Q fever probably due to contact with a parturient cat

Thirty-three cases (24 definite, nine probable) of Q fever were diagnosed in Victoria County, Cape Breton, Nova Scotia from May to August, 1985. Twenty-six of the cases occurred in residents of Baddeck (population 900, attack rate 2.8 percent), and 21 of the cases occurred during the month of June. There was geographic clustering of the cases: 14 of the 33 (42 percent) lived or worked in four buildings located side by side in the center of town. A case control study revealed that 25 of 29 cases were exposed to a cat that gave birth to stillborn kittens on June 8, 1985 and had bled per vaginum for three weeks prior to delivery. The cat lived in one of the buildings where geographic clustering occurred and frequently visited the other buildings. None of the 40 control subjects was so exposed (p less than 0.001). This cat had an antibody titer of 1:512 to Coxiella burnetii phase 1 antigen and a titer of 1:1024 to phase 2 antigen. Exposure to cattle, sheep and goats, the traditional reservoirs of Q fever, was uncommon among patients and control subjects and none of eight cattle tested had antibodies to C burnetii phase I antigen. We conclude that the infected parturient cat was probably responsible for this outbreak of Q fever affecting 2.8 percent of the population of the town of Baddeck.     

Coxiella burnetii pneumonia.

This report reviews the pulmonary and extrapulmonary manifestation of infections due to Coxiella burnetii. Q fever, a zoonosis, is due to infection with C. burnetii. This spore-forming microorganism is a small gram-negative coccobacillus that is an obligate intracellular parasite. The most common animal reservoirs are goats, cattle, sheep, cats, and occasionally dogs. The organism reaches high concentrations in the placenta of infected animals. Aerosolisation occurs at the time of parturition and infection follows inhalation of this aerosol. There are three distinct clinical syndromes of the acute form of the illness: nonspecific febrile illness, pneumonia, and hepatitis. The chronic form of Q fever is almost always endocarditis, but occasionally it is manifest as hepatitis, osteomyelitis or endovascular infection. The pneumonic form of the illness can range from very mild-to-severe pneumonia requiring assisted ventilation. Multiple round opacities are a common finding on chest radiography. Treatment with doxycycline or a fluoroquinolone is preferred. Susceptibility to macrolides is variable. In conclusion, Coxiella burnetii pneumonia should be considered when there is a suitable exposure history and when outbreaks of a pneumonic illness are being investigated.     

A cluster of Coxiella burnetii infections associated with exposure to vaccinated goats and their unpasteurized dairy products.

An outbreak of Q fever occurred among patients and staff of a psychiatric institution in southern France. Some of the patients and staff left the institution daily to work on a farm where goats were raised for raw milk and cheese production. The goats had all been vaccinated annually with a commercial vaccine containing phase II Coxiella burnetii antigen. A serologic survey revealed that 40 (66%) of the 61 patients and staff had elevated titers to C. burnetii. Seropositive persons were more likely to report an acute illness (P = 0.001), fever (P = 0.04), weakness (P = 0.04), arthralgia (P = 0.04), and headaches (P = 0.06) in the preceding year than were seronegative persons. Seropositivity rates were significantly higher among persons who worked on the farm and consumed unpasteurized milk products (69% [22 of 32]; P = 0.007), those who only had worked on the farm (75% [9 of 12]; P = 0.009), and those who only had consumed unpasteurized milk products (75% [9 of 12]; P = 0.009), compared with those who had not worked with the goats or consumed unpasteurized milk products (0 of 5). Despite vaccination against Q fever, no antibodies to C. burnetii were detectable in 17 (59%) of 29 goats. All 12 seropositive goats had antibodies to both phase I and phase II antigens, indicating that they were naturally infected, and two of three goats examined were shedding C. burnetii in their milk. Vaccination of this herd did not prevent the outbreak and might have increased shedding of C. burnetii in the dairy products.     

Q fever

Q fever is a worldwide zoonosis caused by the pathogen Coxiella burnetii causing acute and chronic clinical manifestations. The name "Q fever" derives from "Query fever" and was given in 1935 following an outbreak of febrile illness in an abattoir in Queensland, Australia. C burnetii is considered a potential agent of bioterrorism (class B by the Centers for Disease Control).     

Repeated pregnancies in BALB/c mice infected with Coxiella burnetii cause disseminated infection, resulting in stillbirth and endocarditis

Q fever is a widespread zoonosis caused by the obligate intracellular bacterium Coxiella burnetii. Although this highly virulent organism is most concentrated in mammals during parturition, there are few reports on the manifestations of perinatal Q fever in the human and animal host. The affinity of C. burnetii to pregnancy and its abortifacient potential were investigated in a murine animal model. Intraperitoneal infection of female BALB/c mice with C. burnetii, followed by repeated pregnancies over a 2-year period, resulted in persistent infection associated with abortion and perinatal death, with a statistically significant decrease in viable offspring. In addition, endocarditis occurred in 2 of the adult animals, and C. burnetii antigen and DNA were detected in their heart valves. Taken together, these results demonstrate the abortifacient potential of C. burnetii and the increased risk of persistent infection and endocarditis in pregnant mice, probably related to a decline in cellular immunity during pregnancy.     

An outbreak of cat-associated Q fever in the United States

Q fever is usually acquired by contact with aerosols generated during parturition of domestic ungulates (e.g., sheep, cows, goats). In the maritime provinces of Canada, parturient cats have also been implicated in its transmission. A 66-year-old woman from eastern Maine developed high fever, rigors, headache, myalgias, pulmonary infiltrates, and elevated hepatocellular enzymes, and the diagnosis of acute Q fever was confirmed serologically. She and 14 other family members had attended a family reunion in Maine 2 weeks earlier, when they were exposed to a parturient cat. All 11 adults and older children attending the reunion developed symptoms consistent with acute Q fever. Serum samples were obtained from 10 who attended the reunion and 8 who did not attend. Titers greater than or equal to 1:64 to Coxiella burnetii were present in all who attended the reunion but in none of those who did not. Cat-associated Q fever should be considered when sporadic cases of the disease occur in the United States.     

Q fever: current concepts

Persons with Q fever usually present with severe retrobulbar headache, a fever to 104 degrees F or higher with shaking chills, general malaise, myalgia, chest pain, and sometimes pneumonia and hepatitis. Cattle, sheep, goats, and ticks are the primary reservoirs of the etiologic agent, Coxiella burnetii. Humans are usually infected by inhaling infectious aerosols. Because C. burnetii can survive for long periods in the environment, it poses a continuing health hazard once it is disseminated. Q fever usually occurs sporadically, but large outbreaks are frequently observed throughout the world, particularly among abattoir workers and personnel working in research centers. Q fever endocarditis follows a chronic course and is frequently fatal. Tests for antibodies to C. burnetii are required for confirmation of the diagnosis. Tetracyclines remain the mainstay of treatment for acute Q fever, and tetracyclines in combination with other antibiotics have been advocated for patients with Q fever endocarditis. Vaccines for Q fever have been proven effective in clinical trials.     

Prevalence of Coxiella burnetii in Hungary: Screening of Dairy Cows, Sheep, Commercial Milk Samples, and Ticks

Abstract Q fever is an important zoonotic disease caused by Coxiella burnetii. There are few reliable data about C. burnetii infection available. The aim of this study was to assess the importance and potential infectious sources of Q fever in Hungary. A total of 215 milk samples (10 individual samples from each herd and 1 bulk tank milk sample from each cattle herd), and 400 serum samples (20 from each herd) were tested from 15 dairy cattle herds and 5 sheep flocks located in different parts of Hungary. The study found 19.3% (58/300) and 38.0% (57/150) seropositivity in cattle, and 0% (0/100) and 6.0% (3/50) seropositivity in sheep, by complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA), respectively. C. burnetii DNA was detected by IS1111 element-based TaqMan real-time polymerase chain reaction (PCR) in 8.7% (13/150) of individual dairy cow milk samples, 4.0% (2/50) of individual sheep milk samples, and 66.7% (10/15) of dairy bulk tank milk samples. Samples taken from nine different commercially-available pasteurized cow milk products from different Hungarian producers were also tested for the presence of C. burnetii DNA, and eight of these samples were found to be positive (88.9%). The real-time PCR examination of 5402 ixodid ticks collected from different parts of the country yielded negative results. Knowledge of the true prevalence of Q fever is crucial for policymakers involved in evidence-based decision making.     

Short report: seroprevalence of human infection by Coxiella burnetii in Barcelona (northeast of Spain)

Coxiella burnetii is the causal agent of Q fever, a worldwide-distributed zoonosis, which is endemic in Spain. C. burnetii has an extensive reservoir, including farm animals and pets. The aim of this study was to determine the seroprevalence of C. burnetii in humans in Vallés Occidental (Barcelona, northeast of Spain) and its possible related risk factors. The prevalence of phase II antibodies from 216 subjects was determined by indirect immunofluorescence assay (IFA). Age, sex, living place, occupation, and contact with animals were surveyed. A 15.3% seroprevalence was found (> or = 1/40), and 8.8% of samples had titers > or = 1/80. Seropositive cases were significantly higher in patients > 44 years of age. No statistically significant correlation was found between seropositivity and the remaining variables studied. Therefore, infection by C. burnetii seems to be endemic in our region, with a prevalence ranging from 9% to 15%, depending on the titers that are to be considered significant.     

High seroprevalence of Coxiella burnetii antibodies in veterinarians associated with cattle obstetrics, Bavaria, 2009

Q fever is a zoonosis caused by Coxiella burnetii. Infection can result in severe disease. However, little is known about the risk of infection in veterinarians. In a cross-sectional study among German veterinarians, participants provided sera and completed an exposure questionnaire. We investigated predictors for seropositivity using multivariable logistic regression modelling. The 424 participants' median age was 40 (18-74) years, and 276 (65%) were female. Sera of 162 (38%) were positive for Coxiella burnetii phase II IgG antibodies (by ELISA and IFAT). Predictors for seropositivity were occupational exposure to cattle (aOR 2.83, 95% CI 1.64-4.87), occupational exposure to sheep (2.09, 1.22-3.58), male sex (1.9, 1.15-3.13), and increasing age (30-39 years: 4.91, 2.00-12.04; 40-49 years: 5.32, 2.12-13.33; >50 years: 6.70, 2.60-17.25; compared with <30 years). When investigating occupational exposure to cattle and sheep in detail in a separate model, the seroprevalence increased with increasing numbers of cattle obstetrics procedures performed per month, and with increasing numbers of individual cattle treated per week. The high antibody prevalence implies a high lifetime-risk of Q fever in veterinarians. Cattle veterinarians, especially those frequently performing obstetrics, should be counseled early in their career on the clinical picture of Q fever, and on specific risks.     

Q fever pneumonia

Pneumonia is one of several clinical syndromes that results from inhalation of Coxiella burnetii. This microorganism, the etiologic agent of "Q" (query) fever, infects a wide range of animals and insects. Cattle, sheep, goats, and cats are the reservoirs whereby this agent is spread to humans. High concentrations of C burnetii are present in the placenta and at parturition, the organism is shed into the environment to be inhaled by humans. Following an incubation period that ranges from four to 30 days (mean 14 days), fever, headache, malaise, and cough ensue. The clinical presentation of pneumonia may range from a mild to a severe illness--the latter with the clinical picture of rapidly progressive pneumonia. There are no characteristic features of Q fever pneumonia but the severe headache and the epidemiological history should serve as clues. Treatment with tetracycline or rifampin for two weeks usually results in cure. Many cases of Q fever pneumonia remit without antibiotic therapy. The diagnosis is usually confirmed serologically using a complement fixation or microimmunofluorescence test.     

Q fever endocarditis in the United States.

A patient with Q fever endocarditis, which is almost unknown in the United States, was followed for a total of 32 months; the study was begun 3 1/2 months before aortic valve replacement. Diagnosis was confirmed by serology, visualization of Coxiella burnetii in excised aortic valve tissue by direct and immunofluorescence staining, and isolation of C. burnetii from aortic valve tissue. Serum antibodies against phase I and phase II antigens of C. burnetii were identified. Almost all phase I and phase II antibodies were IgG. These findings are compared with those in an uncomplicated case of acute Q fever. New findings on the immune response to chronic Q fever are presented.