Q Fever Outbreak among Workers at a Waste-Sorting Plant.

An outbreak of Q fever occurred in February-April 2014 among workers at a waste-sorting plant in Bilbao (Spain). The outbreak affected 58.5% of investigated employees, 47.2% as confirmed cases (PCR and/or serology) and 11.3% as probable cases (symptoms without laboratory confirmation). Only employees who had no-access to the waste processing areas of the plant were not affected and incidence of infection was significantly higher among workers not using respiratory protection masks. Detection by qPCR of Coxiella burnetii in dust collected from surfaces of the plant facilities confirmed exposure of workers inside the plant. Animal remains sporadically detected among the residues received for waste-sorting were the most probable source of infection. After cleaning and disinfection, all environmental samples tested negative. Personal protection measures were reinforced and made compulsory for the staff and actions were taken to raise farmers' awareness of the biological risk of discharging animal carcasses as urban waste.

Genetic diversity and variation over time of Coxiella burnetii genotypes in dairy cattle and the farm environment.

The genetic diversity of Coxiella burnetii from 36 dairy cattle herds was determined by Multiple-Locus Variable number tandem repeats Analysis (MLVA), and genotypes from different sources (bulk-tank milk - BTM and surface dust) and sampling time (2009/10 and 2011/12) were compared. A total of 15 different genotypes were identified from 60 BTM and seven dust samples, including seven genotypes reported here for the first time (BN, BO, BP, BQ, BR, BS, BT). The two most prevalent genotypes (J and I), detected both in BTM and dust, accounted for 44.5% of the C. burnetii typed and have been reported infecting cattle worldwide. In 52% of herds more than one genotype was found, and mixed infection with two genotypes was observed in seven BTM samples. Comparison of C. burnetii genotypes at different samplings within each herd detected a change in genotype in 32% of herds, while a persistent genotype was identified in the remaining 68%. In addition, the genotype obtained from dust samples was always identical to that present in the BTM sample. Often persistent genotypes were among the most prevalent types. Clustering of the MLVA genotypes from this and other studies using the minimum spanning tree method separated our C. burnetii strains into two clusters, 10 genotypes clustered within genomic group (GG) III, and the remaining five types (AE, BQ, BR, BS and BT) grouped with GG II, which includes strains implicated in human outbreaks. Although presence in cattle of genotypes closely related to those identified in humans does not seem to be common event, it cannot be neglected and surveillance of genotype distribution is needed to fully understand the epidemiology of Q fever.

Progression of Coxiella burnetii infection after implementing a two-year vaccination program in a naturally infected dairy cattle herd.

BACKGROUND: The high prevalence of Coxiella burnetii infection in dairy cattle herds recently reported and the long survival time of the bacterium in the environment pose a risk to human and animal health that calls for the implementation of control measures at herd level. This study presents the results of a 2-year vaccination program with an inactivated phase I vaccine in a Spanish dairy herd naturally infected with C. burnetii. Calves older than 3 months and non-pregnant heifers and cows were vaccinated in April 2011 and the farm was subsequently visited at a monthly basis for vaccination of recently calved cows and calves that reached the age of 3 months. Annual booster doses were given to previous vaccinated animals as well. The effectiveness of the vaccine was assessed in terms of level of C. burnetii shedding through milk and uterine fluids and environmental contamination as determined by polymerase chain reaction (PCR). RESULTS: The percentage of shedder animals through uterine fluids and milk progressively decreased, and C. burnetii DNA load in bulk-tank milk samples was low at the end of the study. The average seroconversion rate in not yet vaccinated animals, which acted as control group, was 8.6% during the first year and 0% in the second year. DNA of C. burnetii was found in aerosols and dust samples taken in the calving area only at the beginning of the study, whereas slurry samples remained C. burnetii PCR positive for at least 18 months. Multiple Locus Variable number tandem-repeat Analysis identified the same genotype in all C. burnetii DNA positive samples. CONCLUSIONS: In the absence of any changes in biosecurity, the overall reduction of C. burnetii infection in animals to 1.2% milk shedders and the reduced environment contamination found at the end of the study was ascribed to the effects of vaccination together with the culling of milk shedders. Vaccination has to be planned as a medium-long term strategy to suppress risks of re-infection.

Genotyping of Coxiella burnetii from domestic ruminants in northern Spain.

BACKGROUND: Information on the genotypic diversity of Coxiella burnetii isolates from infected domestic ruminants in Spain is limited. The aim of this study was to identify the C. burnetii genotypes infecting livestock in Northern Spain and compare them to other European genotypes. A commercial real-time PCR targeting the IS1111a insertion element was used to detect the presence of C. burnetii DNA in domestic ruminants from Spain. Genotypes were determined by a 6-loci Multiple Locus Variable number tandem repeat analysis (MLVA) panel and Multispacer Sequence Typing (MST). RESULTS: A total of 45 samples from 4 goat herds (placentas, N = 4), 12 dairy cattle herds (vaginal mucus, individual milk, bulk tank milk, aerosols, N = 20) and 5 sheep flocks (placenta, vaginal swabs, faeces, air samples, dust, N = 21) were included in the study. Samples from goats and sheep were obtained from herds which had suffered abortions suspected to be caused by C. burnetii, whereas cattle samples were obtained from animals with reproductive problems compatible with C. burnetii infection, or consisted of bulk tank milk (BTM) samples from a Q fever surveillance programme. C. burnetii genotypes identified in ruminants from Spain were compared to those detected in other countries. Three MLVA genotypes were found in 4 goat farms, 7 MLVA genotypes were identified in 12 cattle herds and 4 MLVA genotypes were identified in 5 sheep flocks. Clustering of the MLVA genotypes using the minimum spanning tree method showed a high degree of genetic similarity between most MLVA genotypes. Overall 11 different MLVA genotypes were obtained corresponding to 4 different MST genotypes: MST genotype 13, identified in goat, sheep and cattle from Spain; MST genotype 18, only identified in goats; and, MST genotypes 8 and 20, identified in small ruminants and cattle, respectively. All these genotypes had been previously identified in animal and human clinical samples from several European countries, but some of the MLVA genotypes are described here for the first time. CONCLUSIONS: Genotyping revealed a substantial genetic diversity among domestic ruminants from Northern Spain.