Search

Objective—To describe the epizootiological investigation of an outbreak of Q fever (Coxiella burnetii infection). Design—Epidemiological study. Animals—17 goat herds in Washington, Montana, and Oregon. Procedures—In April 2011, an abortion storm at a commercial goat farm in Washington was determined to be caused by C burnetii. A joint epidemiological investigation by public health and veterinary professionals was subsequently performed to assess the extent of the outbreak by performing a trace-forward of goats sold from the index farm, to determine risk factors associated with infection, and to implement control measures. A herd management plan was developed to control the outbreak and reduce risk of human exposure. Quarantine and temporary holds preventing the sale or movement of goats allowed time for trace-forward investigation, education of farmers regarding disease risk, and testing to determine the scope of the outbreak. Results—17 farms were affected; 21 human Q fever cases were identified. Bacterial shedding in feces, vaginal fluid, or milk was confirmed in 156 of 629 (25%) goats tested by PCR assay. Seroprevalence of antibodies against C burnetii in goats, determined by ELISA, was 12%. The risk for C burnetii infection in goats was highest among females, those on farms associated with human Q fever, and those on Washington farms. A protective effect was observed for goats at farms where the primary form of goat carcass disposal was burial. Conclusions and Clinical Relevance—This outbreak illustrated the importance of a joint investigation for zoonotic pathogens and the need to expand and strengthen relationships between medical, public health, and veterinary partners. Heightened awareness and enhanced veterinary diagnostic capabilities for C burnetii are needed to identify and control outbreaks expediently.

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 hospitaliza- tion 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.

Q fever is a zoonotic disease caused by inhalation of the bacterium Coxiella burnetii . Ruminant livestock are common reservoirs for C. burnetii , and bacteria present in aerosols derived from the waste of infected animals can infect humans. The significance of infection from material deposited in the environment versus transmission directly from infected animals is not known. In 2011, an outbreak of Q fever cases on farms in Washington and Montana was associated with infected goats. A study was undertaken to investigate the quantity and spatial distribution of C. burnetii in the environment of these goat farms. Soil, vacuum, and sponge samples collected on seven farms epidemiologically linked to the outbreak were tested for the presence of C. burnetii DNA by quantitative PCR. Overall, 70.1% of the samples were positive for C. burnetii . All farms had positive samples, but the quantity of C. burnetii varied widely between samples and between farms. High quantities of C. burnetii DNA were in goat housing/birthing areas, and only small quantities were found in samples collected more than 50 m from these areas. Follow-up sampling at one of the farms 1 year after the outbreak found small quantities of C. burnetii DNA in air samples and large quantities of C. burnetii persisting in soil and vacuum samples. The results suggest that the highest concentrations of environmental C. burnetii are found in goat birthing areas and that contamination of other areas is mostly associated with human movement.

Infected persons had slept in an infested cabin., In February 2006, a diagnosis of sylvatic epidemic typhus in a counselor at a wilderness camp in Pennsylvania prompted a retrospective investigation. From January 2004 through January 2006, 3 more cases were identified. All had been counselors at the camp and had experienced febrile illness with myalgia, chills, and sweats; 2 had been hospitalized. All patients had slept in the same cabin and reported having seen and heard flying squirrels inside the wall adjacent to their bed. Serum from each patient had evidence of infection with Rickettsia prowazekii. Analysis of blood and tissue from 14 southern flying squirrels trapped in the woodlands around the cabin indicated that 71% were infected with R. prowazekii. Education and control measures to exclude flying squirrels from housing are essential to reduce the likelihood of sylvatic epidemic typhus.

Coxiella burnetii is a zoonotic pathogen that causes Q fever in humans and is transmitted primarily from infected goats, sheep, or cows. Q fever typically presents as an acute febrile illness; however, individuals with certain predisposing conditions, including cardiac valvulopathy, are at risk for chronic Q fever, a serious manifestation that may present as endocarditis. In response to a cluster of Q fever cases detected by public health surveillance, we evaluated C. burnetii infection in a community that operates a large-scale cow and goat dairy. A case was defined as an individual linked to the community with a C. burnetii phase II IgG titer ≥ 128. Of 135 participants, 47 (35%) cases were identified. Contact with or close proximity to cows, goats, and their excreta was associated with being a case (relative risk 2.7, 95% confidence interval 1.3-5.3). Cases were also identified among individuals without cow or goat contact and could be related to windborne spread or tracking of C. burnetii on fomites within the community. A history of injection drug use was reported by 26/130 (20%) participants; follow-up for the presence of valvulopathy and monitoring for development of chronic Q fever may be especially important among this population.

Coxiella burnetii is an endemic bacterial pathogen in the United States and the causative agent of Q fever. Two outbreaks of Q fever occurred in Montana during 2011, which led to the issuance of a health alert urging clinicians to test patients with Q fever-compatible illnesses for C. burnetii infection.We retrospectively evaluated the medical records of patients hospitalized for fever, pneumonia, chest pain, and viral infection of unknown etiologies during the two Q fever outbreaks and following the health alert.A total of 103 patients were included in the analysis. Clinicians assessed1% of patients suffering illnesses compatible with Q fever for known risk factors or C. burnetii infection. Only 1 patient had Q fever excluded as a diagnosis.Clinicians should assess for Q fever risk factors and consider the diagnosis in patients hospitalized with Q fever-compatible illnesses when the etiology of illness is unknown. Work is warranted to evaluate the effectiveness of current healthcare alert practices for zoonotic diseases.

Salmonella and Campylobacter infections occur commonly in children. Some of these infections are severe, requiring treatment with antimicrobial agents. Many classes of antimicrobial agents that are used in humans also are used in food animals for growth promotion, disease prevention, and therapy. The use of such antimicrobial agents in food animals increases the likelihood that human bacterial pathogens that have food animal reservoirs, such as Salmonella or Campylobacter, will develop cross-resistance to drugs approved for use in human medicine. Resistance determinants also may be transmitted from food animals to humans through the food supply with bacteria that usually are commensal, such as Escherichia coli and enterococci. Clinicians should be aware that antimicrobial resistance is increasing in food-borne pathogens and that patients who are taking antimicrobial agents for any reason are at increased risk for acquiring antimicrobial-resistant food-borne infections. Several European countries have demonstrated that restricting the use of antimicrobial agents in food animals can be followed by a decrease in antimicrobial resistance in humans without compromising animal health or significantly increasing the cost of production. Appropriate use of antimicrobial agents in humans and food animals is an important factor in maintaining their effectiveness.

We describe the case of a man presumptively diagnosed and treated for Rocky Mountain spotted fever following exposure to multiple ticks while riding horses. The laboratory testing of acute and convalescent serum specimens led to laboratory confirmation of acute Q fever as the etiology. This case represents a potential tickborne transmission ofCoxiella burnetiiand highlights the importance of considering Q fever as a possible diagnosis following tick exposures.

Coxiella burnetii has recently gained military relevance given its potential as a bioterrorism agent, and the multiple cases reported among U.S. military personnel deployed to the Middle East. Sexual transmission of Q fever is rare but has been reported in the literature. We describe the possible sexual transmission of Q fever from a returning serviceman from Iraq to his wife. In a recent editorial commentary, Dr. Raoult wrote about the reemergence of Q fever after September 11, 2001 (Raoult 2009). Indeed, C. burnetii has gained military relevance given its potential as a bioterrorism agent and the multiple cases reported among military personnel deployed in Southwest/Central Asia and North Africa (Botros et al. 1995 , Meskini et al. 1995 , Leung-Shea and Danaher 2006 ). Human serosurveys in these geographic areas have reported prevalence rates for Q fever ranging from 10% to 37% in contrast to the United States, which has an estimated Q fever seroprevalence of 3.1% (Botros et al. 1995, Meskini et al. 1995, Anderson et al. 2009). There is no data available for Q fever seroprevalence in Iraq. As a consequence, native populations in these regions may be more likely to possess immunity, and newcomers, such as U.S. military personnel, would be vulnerable to acute infection (Derrick 1973). We report on the possible sexual transmission of C. burnetii from a serviceman in the late recovery of acute Q fever to his wife.

The use of antimicrobial agents in food animals has caused concern regarding the impact these uses have on human health. Use of antimicrobial agents in animals and humans results in the emergence and dissemination of resistant bacteria. Resistant bacteria from food animals may be passed through the food chain to humans resulting in resistant infections. Increasing resistance to antimicrobial agents that are important in the treatment of human diseases, such as fluoroquinolones and third-generation cephalosporins for the treatment of Salmonella and Campylobacter infections, has significant public health implications. Efforts to mitigate the effects of increasing resistance require collaboration by several partners, including the farming, veterinary, medical, and public health communities.

In February 2001, episodes of acute gastroenteritis were reported to the Wyoming Department of Health from persons who had recently vacationed at a snowmobile lodge in Wyoming. A retrospective cohort study found a significant association between water consumption and illness, and testing identified Norwalk-like virus (NLV) in 8 of 13 stool samples and 1 well. Nucleotide sequences from the positive well-water specimen and 6 of the positive stool samples were identical. This multistrain NLV outbreak investigation illustrates the importance of NLV as a cause of waterborne illness and should encourage monitoring for NLVs in drinking water.

In February 2000, an outbreak of gastroenteritis occurred among employees of a car dealership in New York. The same meal was also supplied to 52 dealerships nationwide, and 13 states reported illness at dealerships where the banquet was served. A retrospective cohort study was conducted to identify risk factors associated with the illness. Stool samples were collected to detect Norwalk-like virus, and sera were drawn and tested for immunoglobulin A antibodies to the outbreak strain. By univariate analysis, illness was significantly associated with consumption of any of four salads served at the banquet (relative risk = 3.8, 95% confidence interval: 2.5, 5.6). Norwalk-like virus was detected by reverse transcription-polymerase chain reaction assay in 32 of 59 stool samples from eight states. Nucleotide sequences of a 213-base pair fragment from 16 stool specimens collected from cases in eight states were identical, confirming a common source outbreak. Two of 15 workers at caterer A had elevated immunoglobulin A titers to an antigenically related Norwalk-like virus strain. This study highlights the value of molecular techniques to complement classic epidemiologic methods in outbreak investigations and underscores the critical role of food handlers in the spread of foodborne disease associated with Norwalk-like virus.