Variables Associated with Infections of Cattle by Brucella abortus., Leptospira spp. and Neospora spp. in Amazon Region in Brazil

The frequency of Neospora spp., Leptospira spp. and Brucella abortus infections in adult cattle was determined in herds of the State of Pará, Brazil, which is an important region for cattle production located in the Amazon region. A total of 3466 adult female cattle from 176 herds were tested, leading to a frequency of seropositive animals of 14.7%, 3.7% and 65.5% and a herd positivity of 87.4%, 41.3% and 98.8% for infections caused by Neospora spp., B. abortus and Leptospira spp., respectively. The five most frequently diagnosed serologic responses to Leptospira spp. were those against serovars hardjo, wolfii, grippotyphosa, hebdomadis and shermani. The following associations were found: practice of artificial insemination, large farm size, large herd size, large number of dogs and high number of total abortions per year with the presence of antibodies against serovar hardjo; positive results to serovar grippotyphosa with the presence of dogs; inappropriate disposal of aborted foetuses with positivity to serovar hebdomadis. Serovar grippotyphosa was also associated with number of episodes of abortions. Neospora spp. positive herds were associated with episodes of abortion and B. abortus infection with the disposal of dead animals and aborted foetuses on pastures and with the use of artificial insemination. In conclusion, the high frequency of brucellosis, leptospirosis and neosporosis in the region may be a consequence of social, natural and raising conditions as: (i) climate conditions that favour the survival and spread of pathogens in the environment; (ii) farms located in regions bordering forest areas; (iii) farms in areas of difficult access to the veterinary service; (iv) extensive beef herds raised at pastures with different age and productive groups inter‐mingled; and (v) minimal concerns regarding hygiene practices and disease prevention measures.     

Serogroups and genotypes of Leptospira spp. strains from bovine aborted foetuses

Leptospirosis is a global disease of animals, with potential major economic impact on livestock industry and important zoonotic capacities. The disease represents a major challenge in the developing countries as humans and animals frequently live in close association. The serovar Hardjo of Leptospira whose primary host is cattle has been studied extensively, but few data exist on other current circulating or emerging serotypes. To better understand the disease in cattle and how to prevent and/or control it, it is necessary to identify the genotype and the serotype of circulating Leptospira . This study presents results of several investigations performed on a historical Belgian collection of congenital jaundice in bovine aborted foetuses coming from the leptospirosis emerging episode of 2014 (Delooz et al., Transboundary and Emerging Diseases, 62, 2015, 124). The results revealed that L.  Grippotyphosa and L.  Australis were the most prevalent serogroups with, respectively, 17/42 and 13/42 positive microscopic agglutination test (MAT) during this emerging event associated with the same clinical pattern. The study also confirms that congenital jaundice is associated with L. kirscheneri and L. interrogans and provides the genotyping of DNA obtained from these two species.     

Molecular evidence to suggest pigeon‐type Chlamydia psittaci in association with an equine foal loss

Chlamydia psittaci is an important avian pathogen with spillover from infected wild and domesticated birds also posing a risk to human health. We recently reported a case of C. psittaci equine placentitis associated with further spillover to humans. Molecular typing of this case revealed it belonged to the 6BC clade of C. psittaci , a globally distributed highly virulent set of strains, typically linked to infection spillover from parrots. Equine chlamydiosis associated with C. psittaci infection has previously been reported elsewhere in countries where parrots are not endemic, however, raising questions over the identity of infecting C. psittaci strains and the potential infection reservoirs. In this study, we describe the detection and molecular characterization of C. psittaci in a case of equine abortion in southern Queensland. Equine placenta and fresh liver and lung tissue from the necropsied foetus were positive by C. psittaci ‐specific qPCR . Chlamydia psittaci ‐specific multilocus sequence typing and omp A genotyping were used to further characterize the detected equine strains and an additional strain obtained from a dove from a different geographic region presenting with psittacosis. Molecular typing of this case revealed that the infecting equine strains were closely related to the C0sittaci detected in dove, all belonging to an evolutionary lineage of C. psittaci strains typically associated with infections of pigeons globally. This finding suggests a broader diversity of C. psittaci strains may be detected in horses and in association with reproductive loss, highlighting the need for an expansion of surveillance studies globally to understand the epidemiology of equine chlamydiosis and the associated zoonotic risk.     

Molecular Study of Dirofilaria immitis and Dirofilaria repens in Dogs from Tunisia

Dirofilaria immitis and Dirofilaria repens are mosquito‐borne nematodes which infect primarily dogs as their main definitive hosts. They cause cardiopulmonary (D. immitis) or cutaneous (D. repens) dirofilariasis in canids and other carnivores and can accidentally be transmitted to humans where they can induce a variety of clinical outcomes depending on organ localization. Dirofilaria spp. infection in dogs was assessed using molecular methods (PCR and sequencing) to identify the different Dirofilaria species occurring in 200 dogs from Northern and Central Tunisia. The overall molecular prevalence of Dirofilaria spp. was 17.5% (35/200). The prevalence of D. immitis (14.5%) was significantly higher than for D. repens (3%). Molecular prevalence of D. immitis was significantly higher in suburban compared to urban and rural regions. There was no difference in molecular prevalence of D. immitis or D. repens according to the dogs’ (sex or use). Dirofilaria immitis amplicons (accession numbers KR676386 ) fall into the same clade with D. immitis from China, India and Taiwan. Comparison of the partial sequences of D. repensITS2 rDNA gene ( KR676387 ) revealed 99.6% similarity with D. repens reported in dogs from USA. It had also 97.6% similarity with D. repens from mosquitoes in Czech Republic. High dog parasite burdens should motivate both medical doctors and veterinarians to consider these frequent infections.     

Systemic Besnoitiosis in a Juvenile Roe Deer (Capreolus capreolus)

Herein, we report the first incidence of systemic besnoitiosis in a male juvenile roe deer Capreolus capreolus. The animal was found dead in an area where bovine besnoitiosis is endemic and showed cachexia and multiple skin erosions in the metacarpal and metatarsal areas. Moreover, round and elevated white structures suggestive of Besnoitia spp. tissue cysts were also present. Twenty‐eight tissue samples from different anatomical locations were collected for microscopic lesion and parasite detection through histopathology and PCR. Immunohistochemistry was performed to confirm Besnoitia‐positive reaction in the tissue cysts. In addition, the identity of Besnoitia spp. in PCR‐positive tissue samples was also investigated using microsatellite (MS) markers, and the comparison of protein disulphide isomerase gene sequences (BbPDI) of B. besnoiti and B. tarandi isolated from cattle and reindeer, respectively. Besnoitia cysts were detected in the skin (several parts), respiratory and upper digestive tracts, eyes, kidney, liver, testicle, cardiac muscle and lymphoid tissue. Remarkably, the presence of tissue cysts in the brain confirmed the capacity of Besnoitia spp. to form tissue cysts in the central nervous system (CNS). Finally, the Besnoitia species detected showed the same MS genotype as B. besnoiti, and BbPDI sequences from roe deer and two B. besnoiti isolates were genetically identical throughout multiple sequence alignment. Thus, for the first time, there is evidence that roe deer might act as an intermediate host of B. besnoiti. Further molecular analyses and parasite isolations are needed to corroborate these findings.     

The red fox (Vulpes vulpes) as a potential natural reservoir of human cryptosporidiosis by Cryptosporidium hominis in Northwest Spain

Giardia duodenalis and Cryptosporidium spp. are ubiquitous intestinal protozoa that parasitize domestic and wild animals, as well as human beings. Due to their zoonotic potential, the objective of the present study was to determine the presence of these pathogens in the fox population (Vulpes vulpes) located in Northwest Spain. A total of 197 faecal samples from legally hunted foxes were collected in the autonomous region of Galicia. The presence of G. duodenalis and Cryptosporidium spp. was investigated by PCR‐based methods amplifying the small subunit ribosomal RNA (ssu rRNA) gene of the parasites. Attempts to genotype obtained positive samples were subsequently conducted at the glutamate dehydrogenase (gdh) and β‐giardin (bg) genes of G. duodenalis, and the 60 kDa glycoprotein (gp60) gene of Cryptosporidium. Giardia duodenalis and Cryptosporidium spp. were identified in 19 (9.6%) and 12 (6.1%) of the investigated samples, respectively. However, five Cryptosporidium species were detected at the ssu rRNA locus: C. hominis (33.4%, 4/12), C. canis (25.0%, 3/12), C. parvum (16.7%, 2/12), C. ubiquitum (8.3%, 1/12) and C. suis (8.3%, 1/12). An additional Cryptosporidium‐positive sample was identified at the genus level only. Typing and subtyping of Giardia‐ and Cryptosporidium‐positive samples were unsuccessful. The detection of C. hominis in wild foxes indicates the probable overlapping of sylvatic and domestic cycles of this parasite in rural settings. Besides, this finding raises the question of whether red foxes may act as natural reservoirs of C. hominis. The detection of C. parvum and C. suis is suggestive of active transmission events between farm and wild animals, opening up the possibility of transmission to human beings.     

Seroepidemiological and molecular investigation of spotted fever group rickettsiae and Coxiella burnetii in Sao Tome Island: A One Health approach

Spotted fever group rickettsiae (SFGR) and Coxiella burnetii are intracellular bacteria that cause potentially life‐threatening tick‐borne rickettsioses and Q fever respectively. Sao Tome and Principe (STP), small islands located in the Gulf of Guinea, recently experienced a dramatic reduction in the incidence of malaria owing to international collaborative efforts. However, unexplained febrile illnesses persist. A One Health approach was adopted to investigate exposure to SFGR and C. burnetii in humans and examine the diversity of these bacteria in ticks parasitizing domestic ruminants. A cross‐sectional human serological study was conducted in Agua Grande district in Sao Tome Island from January to March 2016, and ticks were collected from farmed domestic ruminants in 2012 and 2016. In total, 240 individuals varying in age were randomly screened for exposure to SFGR and C. burnetii by indirect immunofluorescence assay. Twenty of 240 individuals (8.3%) were seropositive for SFGR (4 for Rickettsia africae and 16 for R. conorii) and 16 (6.7%) were seropositive for C. burnetii. Amblyomma astrion were collected exclusively in 2012, as were A. variegatum in 2016 and Rickettsia spp. were detected in 22/42 (52.4%) and 49/60 (81.7%) respectively. Sequence analysis of multiple gene targets from Rickettsia spp. detected in ticks suggests the presence of a single divergent R. africae strain (Sao Tome). While no ticks were found positive for C. burnetii, Coxiella‐like endosymbionts were detected in nearly all ticks. This is the first study in STP to provide serological evidence in humans of SFGR and C. burnetii and additional molecular evidence in ticks for SFGR, which may be responsible for some of the unexplained febrile illnesses that persist despite the control of malaria. Future epidemiological studies are needed to confirm the occurrence and risk factors associated with SFG rickettsioses and Q fever in both humans and animals.     

Molecular epidemiology of Mycobacterium tuberculosis complex strains isolated from livestock and wild animals in Italy suggests the need for a different eradication strategy for bovine tuberculosis

Bovine tuberculosis (bTB ) is an important zoonosis, which has been re‐emerging in different ecological scenarios. In Sicily, Italy, from 2004 to 2014, an anatomopathological survey for tuberculosis‐like lesions both in farmed and wild animals was performed. The isolates were genotyped using spoligotyping and Mycobacterial Interspersed Repetitive Units‐Variable Number of Tandem Repeats (MIRU ‐VNTR ) techniques. High prevalence of lesions was observed for cattle (4%), pigs (4.9%) and wild boars (6.8%), and a total of 625 Mycobacterium bovis isolates were identified. Genotyping analysis showed the presence of 37 different spoligotypes including fifteen spoligotypes not present in other Italian regions and 266 MIRU ‐VNTR profiles. Spoligotype SB 0120 exhibited the highest prevalence in cattle (50%) and pigs (56%) and the highest genetic variety with 126 different MIRU ‐VNTR profiles. The isolation of M. bovis in a farmer underlines the importance of M. bovis identification during the human TB diagnostic processes. This study supported the use of the genotyping analysis as a valuable tool for the evaluation of the epidemiological role of pigs and other domestic reservoirs such as goats and the role of wildlife in the maintenance of bTB infection.     

Molecular epidemiology of meticillin-resistant Staphylococcus aureus in Italian cystic fibrosis patients: A national overview

Background

The genetic background, transmissibility and virulence of MRSA have been poorly investigated in the cystic fibrosis (CF) population.The aim of this multicentre study was to analyse MRSA strains isolated from CF patients attending nine Italian CF care centres during a two-year period (2004-2005). All CF patients infected by MRSA were included.

Method

Antibiotic susceptibility testing, SCCmec typing, Panton-Valentine Leukocidin (PVL) production, and Multi Locus Sequence Typing (MLST) analysis were carried out on collected isolates (one strain per patient).

Results

One hundred and seventy-eight strains isolated from 2360 patients attending the participating centres were analysed. We detected 56 (31.4%) SCCmec IV PVL-negative strains, with a resistance rate of 80.3% to clindamycin and of 14.5% to trimethoprim/sulphamethoxazole. MLST analysis showed that many isolates belonged to known epidemic lineages. The largest clone grouping of 29 isolates from 6 centres had the genetic background (ST8-MRSA-IV) of the American lineages USA300 and USA500, thus demonstrating the diffusion of these strains in a population considered at risk for hospital associated infections.

Conclusions

Known MRSA epidemic clones such as USA600, USA800, USA1100, and UK EMRSA-3 were described for the first time in Italy. The diffusion of MRSA strains with high pathogenic potential in the CF population suggests that analysis of the MRSA strains involved in pulmonary infections of these patients is needed.     

Genomic epidemiology of the emerging pathogen Batrachochytrium dendrobatidis from native and invasive amphibian species in Chile

Emerging fungal diseases represent a threat to food security, animal and human health worldwide. Amphibian chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd ), has been associated with catastrophic and well‐documented amphibian population declines and extinctions. For the first time, Bd was cultured from native and non‐native wild amphibians in Chile. Phylogenomic analyses revealed that Chilean isolates AVS2, AVS4 and AVS7 group within the global panzootic lineage of Bd (Bd GPL) in a single highly supported clade that includes a genotype previously isolated from the United Kingdom. Our results extend the known distribution of Bd GPL in South America and suggest a single and relatively recent introduction of Bd GPL into the country, providing additional support to the role of anthropogenic activity in the global spread of this panzootic lineage.     

Acute cellular rejection and HLA mismatch in heart transplantation: insights from a developing country

The notable evolution of heart transplant (HTX) has paralleled the capacity of diagnosing rejection and, consequently, initiating timely treatment. Acute cellular rejection, diagnosed by endomyocardial biopsy, is the most frequent in the first 6 months after HTX. HLA matching is not routinely performed in HTX due to the absence of consensus regarding its usefulness. However, the use of HLA typing might be underscored if it could predict an increased risk of rejection. Therefore, the aim of this study was to evaluate, at a public cardiology center in Brazil, the association between HLA mismatches and the incidence of acute cellular rejection in the first 6 months after HTX. Data were obtained from hospital records and from the National Transplant System. Overall, there was no association between the number of HLA mismatches and the frequency of acute cellular rejection, but there was a tendency toward a higher incidence of rejection with HLA‐DR incompatibility.     

Genetic Characterization of Circulating African Swine Fever Viruses in Nigeria (2007–2015)

Sequencing and analysis of three discrete genome regions of African swine fever viruses (ASFV) from archival samples collected in 2007–2011 and active and passive surveillance between 2012 and 2015 in Nigeria were carried out. Analysis was conducted by genotyping of three single‐copy African swine fever (ASF) genes. The E183L and B646L genes that encode structural proteins p54 and p72, respectively, were utilized to delineate genotypes before intragenotypic resolution by characterization of the tetrameric amino acid repeat region within the hypervariable central variable region of the B602L gene. The results showed no variation in the p72 and p54 gene regions sequenced. Phylogeny of p72 sequences revealed that all the Nigerian isolates belonged to genotype I, while that of the p54 recovered the Ia genotype. Analysis of B602L gene revealed the differences in the number of tetrameric repeats. Four new variants (Tet‐15, Tet‐17a, Tet‐17b and Tet‐48) were recovered, while a fifth variant (Tet‐20) was the most widely distributed in the country displacing Tet‐36 reported previously in 2003–2006. The viruses responsible for ASF outbreaks in Nigeria are from very closely related but mutated variants of the virus that have been circulating since 1997. A practical implication of the genetic variability of the Nigerian viral isolates in this study is the need for continuous sampling and analysis of circulating viruses, which will provide epidemiological information on the evolution of ASFV in the field versus new incursion for informed strategic control of the disease in the country.     

First Molecular Identification and Genetic Characterization of Theileria lestoquardi in Sheep of the Maghreb Region

Theileria lestoquardi is the most prominent Theileria species in small ruminants that causes malignant theileriosis of sheep in Africa and Asia. In the present survey, blood samples and ticks were collected in Kebili (southern Tunisia) from 166 Queue Fine de l'Ouest sheep. Giemsa‐stained blood smears, immunofluorescent antibody test (IFAT) and PCR were performed. The DNA was extracted from blood and analysed by PCR targeting 18S rRNA gene of Theileria spp. and then sequenced. A total number of 140 ticks were collected from a total number of 166 sheep during the four seasons. The ticks belonged to two genera and 4 species; the most frequent tick was Hyalomma excavatum 84.3% (118/140) and then Rhipicephalus spp. 15.7% (22/140). Only two animals had positive Giemsa‐stained blood smears, and they were also positive by IFAT. The amplicons had 99.3 and 99.6% homology with the BLAST published T. lestoquardi amplicons. To our knowledge, this is the first report of T. lestoquardi in small ruminants within the Maghreb region.     

Molecular Survey of Anaplasma and Ehrlichia of Red Deer and Sika Deer in Gansu,China in 2013

Anaplasma and Ehrlichia are important emerging tick‐borne pathogens in both humans and animals. Here, we conducted a molecular surveillance study in Gansu, China to assess the prevalence of Anaplasma and Ehrlichia spp. in red deer and sika deer based on polymerase chain reaction (PCR) analysis and sequencing of 16S rRNA or msp genes. PCR revealed that the prevalence of Anaplasma ovis, Anaplasma bovis and Anaplasma platys of the Qilian Mountain samples was 32%, 9% and 9%, respectively; the prevalence of Anaplasma ovis, Anaplasma bovis, Anaplasma platys was 20%, 15% and 15% among the Long Mountain samples, respectively. Of the Long Mountain samples, two (5%) of the 40 samples were positive for Ehrlichia canis, but all 44 of the Qilian Mountain samples were negative for E. canis, and no other Anaplasma or Ehrlichia spp. were found in the samples. The phylogenetic tree showed that the newly isolated Anaplasma and Ehrlichia spp. could be classified as belonging to four clades, including an A. bovis cluster, A. ovis cluster, A. platys cluster and E. canis cluster. In addition, Bartonella schoenbuchensis was firstly identified in blood samples from red deer in Gansu, China. Our results provide important data to increase the understanding of the epidemiology of anaplasmosis and ehrlichiosis of red deer and sika deer and will assist with the implementation of measures to control anaplasmosis and ehrlichiosis transmission to red deer, sika deer and other animals in Gansu, China.     

Spatial distribution and spread potential of sixteen Leptospira serovars in a subtropical region of Brazil

Leptospirosis is a bacterial disease that represents a major problem in animal and public health due to its high prevalence and widespread distribution. This zoonotic disease is most prevalent in tropical environments where conditions favour pathogen survival. The ecological preferences of Leptospira serovars are poorly understood, limiting our knowledge of where and when outbreaks can occur, which may result in misinformed prevention and control plans. While the disease can occur consistently in time and space in tropical regions, research on the ecology of leptospirosis remains limited in subtropical regions. This research gap regarding Leptospira ecology brings public and veterinary health problems, impacting local economies. To fill this gap of knowledge, we suggest to assess geographic and ecological features among Leptospira serovars in a subtropical area of Brazil where leptospirosis is endemic to (a) highlight environmental conditions that facilitate or limit Leptospira spread and survival and (b) reconstruct its geographic distribution. An ecological niche modelling framework was used to characterize and compare Leptospira serovars in both geographic and environmental space. Our results show that despite the geographic overlap exhibited by the different serovars assessed, we found ecological divergence among their occupied ecological niches. Ecological divergences were expressed as ranges of potential distributions and environmental conditions found suitably by serovar, Sejroe being the most asymmetric (<0.15). Most important predictors for the potential distribution of most serovars were soil pH (31.7%) and landscape temperature (24.2%). Identification of environmental preferences will allow epidemiologists to better infer the presence of a serovar based on the environmental characteristics of regions rather than inferences based solely on historical epidemiological records. Including geographic and ecological ranges of serovars also may help to forecast transmission potential of Leptospira in public health and the food animal practice.     

Molecular,serological, pathological,immunohistochemical and microbiological investigation of Brucella spp. in marine mammals of Brazil reveals new cetacean hosts

Brucella‐exposure and infection is increasingly recognized in marine mammals worldwide. To better understand the epidemiology and health impacts of Brucella spp. in marine mammals of Brazil, molecular (conventional PCR and/or real‐time PCR), serological (Rose Bengal Test [RBT], Competitive [c]ELISA, Serum Agglutination Test [SAT]), pathological, immunohistochemical (IHC) and/or microbiological investigations were conducted in samples of 129 stranded or by‐caught marine mammals (orders Cetartiodactyla [n = 124], Carnivora [n = 4] and Sirenia [n = 1]). Previous serological tests performed on available sera of 27 of the 129 animals (26 cetaceans and one manatee), indicated 10 seropositive cetaceans. Conventional PCR and/or real‐time PCR performed in cases with available organs (n = 119) and/or blood or swabs (n = 10) revealed 4/129 (3.1%) Brucella‐infected cetaceans (one of them with positive serology; the remaining three with no available sera). Pathological, IHC and/or microbiological analyses conducted in PCR/real‐time PCR and/or seropositive cases (n = 13) revealed Brucella‐type lesions, including meningitis/meningoencephalitis, pneumonia, necrotizing hepatitis, pericarditis and osteoarthritis in some of those animals, and positive IHC was found in all of them (excepting two live‐stranded animals without available organs). Brucella spp. culture attempts were unsuccessful. Our results demonstrated exposure, asymptomatic, acute and chronic Brucella sp. infection in several cetacean species in the Brazilian coast, highlighting the role of this pathogen in stranding and/or death, particularly in Clymene dolphin (Stenella clymene) and short‐finned pilot whale (Globicephala macrorhynchus) off Ceará State. Novel hosts susceptible to Brucella included the franciscana (Pontoporia blainvillei), the Guiana dolphin (Sotalia guianensis) and the spinner dolphin (Stenella longirostris). Additionally, three coinfection cases involving Brucella spp. and cetacean morbillivirus, Edwarsiella tarda and Proteus mirabilis were detected. To the best of our knowledge, this is the first long‐term and large‐scale survey of Brucella spp. in marine mammals of South America, widening the spectrum of susceptible hosts and geographical distribution range of this agent with zoonotic potential.     

Molecular detection of Chlamydia trachomatis and semen quality of sexual partners of infertile women

Chlamydia trachomatis is considered as the bacterium that is more sexually transmitted as cause of male urethritis, epididymitis, orchitis and infertility. A total of 116 semen samples of men whose couples are infertile women were analysed. The quality of the semen was measured by standard procedures recommended by WHO while C. trachomatis was detected by the PCR assay. Thirty‐seven semen samples were positive for C. trachomatis (31.9%). Regarding semen analysis, no different values were observed between positive and negative samples to C. trachomatis. However, the presence of leucocytes and erythrocytes suggests an inflammatory process; however, these were high in negative samples to C. trachomatis. Furthermore, an association between low seminal volume at 1, 5 ml and the positivity to C. trachomatis was observed (OR=2, 1; CI₉₅% 1,16‐3,07). The total semen volume is a contribution by the various accessory glands (this reflects the secretory activity of the glands); a low semen volume could be due to an obstruction of the ejaculatory duct or infection of accessory glands by C. trachomatis. More studies are necessary to identify the causes of a reduced semen volume.     

Q Fever Dairy Herd Status Determination Based on Serological and Molecular Analysis of Bulk Tank Milk

Ruminants are recognized as the main reservoirs of Coxiella burnetii. EFSA highlighted the lack of knowledge about Q fever prevalence in many European countries. A cross‐sectional study was carried out in randomly selected dairy herds (n = 109) from central Portugal to screen for C. burnetii infection and to correlate it with herd factors. Bulk tank milk (BTM) samples from cattle (n = 45) and small ruminant (n = 64) herds were tested by ELISA and PCR. The apparent seroprevalence of Q fever was estimated in 45.9% (95% CI: 36.3–55.7) being higher in small ruminants (51.6; 95% CI: 39.6–63.4) than in cattle (37.8; 95% CI: 25.1–52.4). The shedding of C. burnetii in BTM was detected in 11.9% (95% CI: 7.1–19.4) of BTM, and it was higher in cattle (20%; 95% CI: 10.9–33.8) than in sheep and mixed herds (6.3%; 95% CI: 2.5–15). A high bacterial load (≥ 3 × 10³ bacteria/ml) was observed in 85% of PCR‐positive BTM. A significant correlation was found between the bacterial load and positive samples on ELISA (P < 0.001). Antibody positivity was significantly associated with the increased herd size (P < 0.01) and the occurrence of abortion (P < 0.05), whereas the shedding of C. burnetii was significantly associated with the report of infertility (P < 0.05). The results highlight that serological and molecular methods in combination are a useful tool to screen for Q fever and to clarify the herd infection status. The shedding of C. burnetii through milk is important, especially in dairy cattle, and thus, the role of milk as a potential source of infection among dairy workers should not be neglected. To our knowledge, this is the first study reporting C. burnetii infection in dairy livestock in Portugal showing that Q fever is significant in dairy herds, leading to economic losses and being a risk for public health, which highlights the need of implementation of control measures.