Prevalence and risk factors associated with bovine viral diarrhea virus infection in dairy herds in Jordan

A cross-sectional study was carried out to determine the seroprevalence and to identify risk factors associated with bovine viral diarrhea virus (BVDV) infection in 62 non-vaccinated dairy herds (671 cows) in Jordan between January and June 2007. Information regarding herd management was recorded through a personal interview with farmers. Antibodies against BVDV were detected using an indirect ELISA test. Chi-square analysis and multivariable logistic regression model were used to identify risk factors for BVDV seropositivity. The true prevalence of antibodies against BVDV in individual cows and cattle herds was 31.6% and 80.7%, respectively. The seroprevalence of BVDV in medium and large size herds was significantly higher than that in smaller herds. There was no significant difference in BVD seroprevalence between different age groups. Random-effects logistic regression model revealed two major factors associated with seropositivity to BVDV; exchange of visits between adjacent farm workers and not isolating newly purchased animals before addition to the herd. The seroprevalence of BVDV in cows located in the northern Jordanian governorates was significantly higher than that in other studied governorates. Results of this study indicated that BVDV is highly prevalent in Jordan and BVDV infection could be controlled by livestock-trade control, and applying strict biosecurity measures in the dairy farms.     

Seroprevalence and risk factors for bovine brucellosis in Jordan

We investigated the seroprevalence and risk factors for Brucella seropositivity in cattle in Jordan. The sera from 671 cows were randomly collected from 62 herds. The antibodies against Brucella were detected using a Rose Bengal plate test and indirect ELISA. A structured questionnaire was used to collect information on the cattle herds'' health and management. A multiple logistic regression model was constructed to identify the risk factors for Brucella seropositivity. The true prevalence of antibodies against Brucella in individual cows and cattle herds was 6.5% and 23%, respectively. The seroprevalence of brucellosis in cows older than 4 years of age was significantly higher than that in the younger cows. The seroprevalence of brucellosis in cows located in the Mafraq, Zarqa and Ma''an governorates was significantly higher than that of the other studied governorates. The multiple logistic regression model revealed that a larger herd size (odd ratio = 1.3; 95% CI: 1.1, 2.6) and mixed farming (OR = 2.0; 95% CI: 1.7, 3.7) were risk factors for cattle seropositivity to Brucella antigens. On the other hand, the use of disinfectants (OR = 1.9; 95% CI: 1.1, 2.1) and the presence of adequate veterinary services (OR = 1.6; 95% CI: 1.2, 3.2) were identified as protective factors.     

Prevalence and risk factors associated with Chlamydophila abortus infection in dairy herds in Jordan

A cross-sectional study was carried out to determine seroprevalence and to identify risk factors associated with Chlamydophila abortus infection in 62 nonvaccinated dairy herds (671 cows) in Jordan between January and June 2007. Information regarding herd management was recorded through a personal interview with farmers. Antibodies against C. abortus were detected using an ELISA test kit. Chi-square analysis and multivariable logistic regression model were used to identify risk factors associated with C. abortus seropositivity. The true prevalence of antibodies against C. abortus in individual cows and cattle herds were 19.9?% and 66.3?%, respectively. Univariable Chi-square analysis revealed three variables with P????0.25 that were further offered to multivariable logistic regression analysis. Small-sized herds were identified as a risk factor for seropositivity to C. abortus, while sweeping followed by water hosing and using disinfectants were identified as protective factors. Cows in the age groups of >8 and ??10?years old and >2 and ??6?years old had the highest and lowest significant seroprevalence to C. abortus, respectively. Results of this study indicated that C. abortus is highly prevalent in Jordan's dairy herds and Chlamydophila infection could be controlled by applying strict biosecurity measures in the dairy farms.     

Cholinesterase as an inflammatory marker of subclinical infection of dairy cows infected by Neospora caninum and risk factors for disease

The aim of this study was to evaluate the seroprevalence of Neospora caninum in dairy cows, as well as to verify the risk factors for N. caninum infection and inflammatory response in dairy cows. Using the indirect immunofluorescence reaction, the seroprevalence of neosporosis was determined to be 32.82%. Based on regression analysis, the presence of dogs at a farm increased the probability of a cow testing positive for N. caninum (OR = 20.01 [5.21–123.12]). These data suggest that N. caninum has a relevant prevalence in dairy cows of the Microregion of Rio do Sul (Brazil), with elevated frequencies of anti-N. caninum IgG. The data also suggest that the parasite is widely distributed in dairy herds of the micro-region, because 94.4% of properties screened had at least one seropositive animal. The principal risk factors for disease maintenance in herds may be considered the presence of dogs and absence of a diagnostic test when introducing new animals. Blood from these cows was used to measure variables related to the inflammatory response. Serum cholinesterase activity, as well as serum levels of globulins and C-reactive protein were higher in seropositive to N. caninum than in seronegative cows. Furthermore, the infection by parasite causes an intense inflammatory process, contributing to disease pathophysiology.     

Seroprevalence,spatial distribution and risk factors of Borrelia burgdorferi sensu lato in Jordan

Lyme borreliosis has not been studied in Jordan or in much of the Middle East. However, limited research indicates that the tick vector, Ixodes ricinus, exists in the region. This study examined the seroprevalence of B. burgdorferi s.l. in Jordan and potential demographic and zoonotic risk factors for seropositivity. Serum samples of 824 apparently healthy participants from 11 governorates in Jordan were tested for B. burgdorferi s.l. using Enzygnost Lyme link VlsE/IgG enzyme-linked immunosorbent assay. A validated questionnaire was used to collect demographic and animal exposure data. Univariate and multivariate logistic regression were used to identify factors associated with seropositivity. The results showed that 11.7 % (95 % CI, 9.3–14.0 %) of the participants were seropositive for B. burgdorferi s.l.. There was a bimodal age distribution of seroprevalence with higher seroprevalence among individuals <20 and>60 years old. After controlling for governorate of residence, females had 2.77 (95 % CI 1.53–5.00) times greater odds of seropositivity compared to males. Individuals living in the southeastern part of Jordan (Ma’an) had 2.32 (95 % CI, 1.02−5.31) greater odds of seropositivity compared to those living in Amman, the Capital of Jordan, while those living in the northeast had significantly lower odds of seropositivity. This study presents the first evidence of B. burgdorferi s.l. seropositivity in Jordan and suggests several risk factors which were reported in studies conducted elsewhere. This study suggests that Lyme borreliosis should be considered in the differential diagnosis for patients presenting with skin lesions in Jordan.     

Seroprevalence of Toxoplasma gondii and Neospora caninum in sheep intended for human consumption in the Rondônia state,Western Brazilian Amazon

The aim of this study was to carry out a seroepidemiological study of anti-T. gondii and anti-N. caninum antibodies in serum samples from sheep intended for human consumption in the Rondônia state, in the Western Brazilian Amazon, and identify possible risk factors associated with seropositivity. The analysis of the 616 sheep serum samples revealed animal-level seroprevalence of T. gondii in the order of 52.4 % and of N. caninum of 60.6 %. Prevalence of co-infections was 33.4 %. The herd-level seroprevalence was 100 % for both the parasites. Applying of multivariate logistic regression analysis, test of the association between seroprevalence of T. gondii infection and the potential predictors showed that feed, fetal malformation, abortion, neurological problems (lambs), presence of rodents were the significant (P < 0.05) predictors. The variables presence of rodents, cats, wild animals and main activity showed statistical association (P < 0.05) with the seroprevalence of N. caninum. Due to the high prevalence of T. gondii and N. caninum found in this study, the absence of specific slaughterhouses for sheep and raw or undercooked sheep meat for human consumption we concluded that sheep can represent an important source of infection for humans.     

Seroprevalence and risk factors associated with exposure of water buffalo (Bubalus bubalis) to Neospora caninum in northeast Thailand

Water buffalo are important draft animals for agriculture in resource-restricted areas worldwide. Water buffalo were shown to be experimentally susceptible to infection with Neospora caninum, potentially affected by neosporosis, and naturally exposed to the parasite in Asia. Although enzootic to Thailand, the distribution of N. caninum among Thai water buffalo is unclear. The objectives of this study were to determine the seroprevalence of N. caninum among water buffalo of northeast Thailand and to identify risk factors associated with their exposure to N. caninum. Sera from 628 water buffalo from 288 farms were tested with an indirect fluorescent antibody test (IFAT). A total of 57 samples from 48 herds contained antibodies to N. caninum, indicating overall seroprevalence of 9.1% and 16.7% among individual animals and herds, respectively. The overall seroprevalence was highest in provinces located in the Khorat Basin in the southern part of the region tested. Host age was also associated with seroprevalence, with the greatest seroprevalence (16.1%) among buffalo over 10 years of age, followed by 5–10 years of age (13.4%), 3–5 years (9.2%), and less than 3 years (1.2%). These results collectively suggested that horizontal transmission from canine definitive hosts was an important route of water buffalo exposure to N. caninum. These results also verified the importance of risk factor analysis for effective bovine neosporosis control strategies at the local level.     

Factors associated with seroprevalence of Neospora caninum in dairy cattle in southeastern Brazil

Neosporosis is an infectious disease caused by Neospora caninum, an obligate intracellular cyst-forming protozoan considered a major cause of miscarriage in dairy cattle in many parts of the world. This cross-sectional study evaluated the relationship between reproductive abnormalities and seropositivity to N. caninum in 1,204 dairy cows from 40 farms located in the state of Minas Gerais, southeastern Brazil. Producers were interviewed, and blood samples were collected to perform indirect immunofluorescence tests (IFAT 1:200). Association between reproductive abnormalities and seropositivity in cattle was evaluated with generalized estimating equations. The true herd-level seroprevalence of N. caninum was 95 % (83.3–99.1), while the individual-level true seroprevalence was 21.6 % (19.2–24.2). Several reproductive abnormalities were significantly associated with seropositivity to N. caninum: occurrence of repeated estrus (p?=?0.02; OR?=?3.84; 95 % CI?=?1.239–11.893), repeated miscarriages (p?=?0.001; OR?=?2.54; 95 % CI?=?1.423–5.402), and temporary anestrus (p?=?0.001; OR?=?3.44; 95 % CI?=?1.976–5.994). Furthermore, loose dogs (p?=?0.041; OR?=?2.20; 95 % CI?=?1.033–4.672) when fed raw meat (p?=?0.001; OR?=?1.91; 95 % CI?=?1.443–2.519) are risk factors for N. caninum infection. We observed that seropositivity to N. caninum in cattle increases risk of miscarriage by almost twice throughout the reproductive life of cows (p?=?0.004; OR?=?1.978; 95 % CI?=?1.249–3.131). Serologic evidence in this study indicates that N. caninum infection is widely distributed among dairy herds and significantly associated with reproductive disorders, especially miscarriage, repeated estrus, and temporary anestrus.     

Risk factors associated with camel brucellosis in Jordan

During the period between February, 2004 and December, 2006, a cross-sectional study was performed to investigate some epidemiological aspects related to camel brucellosis in Jordan. Four hundred twelve camel sera from 37 herds were randomly collected and analyzed using Rose Bengal plate test and complement fixation test. A structured pre-tested questionnaire was administered to collect information on camel herd health and management. A multivariable logistic regression model was constructed to investigate risk factors associated with seropositivity to Brucella antigens. Moreover, the incidence of Brucella-specific abortion was investigated in 7 camel herds located in different locations in Southern Jordan. The true prevalence of Brucella-seropositive in camels was 12.1%. Thirteen (35.1%) herds had at least one positive camel. The seroprevalence of brucellosis in camels was significantly higher in the southern part of Jordan than that in central or northern Jordan. The multivariable logistic regression model on both individual and herd levels revealed large herds and contact with small ruminants as risk factors for Brucella seropositivity. On the other hand, using disinfectants was identified as a protective factor (OR = 0.8; 95% CI: 0.1, 0.9) only on the camel herd level. The incidence of Brucella-caused abortion was 1.9%. Brucella melitensis biotype 3 was isolated from 4 aborted camel fetuses.     

Associations of Neospora caninum seropositivity with gestation number and pregnancy outcome in Danish dairy herds

The prevalence and distribution of seropositivity towards the protozoan parasite Neospora caninum were studied in single blood samples from 1561 cows from 31 Danish dairy herds. Blood samples were analysed by an indirect enzyme-linked immunoassay and an indirect fluorescent-antibody test. Seroprevalence in 15 herds with previous abortions assigned to neosporosis ranged from 1% to 58%, with a mean frequency of 22%. In eight out of 16 herds without a history of N. caninum related abortions, no seroreactors were found. In the remaining eight herds, the seroprevalence ranged from 6% to 59%. The prevalence and distribution of seropositivity, gestation number prior to sampling, and breed were related to abortions and perinatal deaths using a random-effects logistic-regression model. Abortion risk was significantly increased in seropositive animals (OR=3) and in 2nd-gestation cows (OR=3). Perinatal death was significantly influenced by gestation number and breed, but not by serostatus. Reproductive performance and culling risk of cows were not affected by serostatus. Seropositivity increased with “age” (i.e. gestation number) (P=0.02). In open cows, seropositivity tended to decrease with distance from calving (P=0.05). The proportion of seropositive pregnant cows increased with trimester (P=0.02).     

Epidemiological pattern and risk factors associated with bovine viral-diarrhoea virus (BVDV) infection in a non-vaccinated dairy-cattle population from the Asturias region of Spain

A survey of bovine viral-diarrhoea virus (BVDV) infection was carried out in a non-vaccinated cattle population from the Asturias region of Spain in 1997 to assess seroprevalence and identify risk factors associated with infection. Twenty-eight herds were included; 529 cows were bled. Information regarding the herd and each animal sampled were recorded through a personal interview with the farmer. The true prevalence was estimated to be 21%. According to the antibody-age profiles and the herd-management characteristics, no persistently infected animals were suspected at that time within the herds sampled. Random-effects logistic regression found two major factors associated with seropositivity: age and cow origin. Results suggested that BVDV infection could be controlled in that area by livestock-trade control (without vaccines). In addition, an increasing risk of abortion was not observed when cows were seropositive to both BVDV and Neospora caninum infections.     

Bovine viral diarrhoea virus in beef cattle herds of Yucatan, Mexico: seroprevalence and risk factors

A survey of bovine viral diarrhoea virus (BVDV) infection was carried out from June 2001 to July 2002 in a non-vaccinated beef cattle population from the livestock region of Yucatan, Mexico, to assess seroprevalence and identify risk factors related to seroprevalence. The aim was also to estimate the intra-herd correlation (r_e) and design effect (D) of BVDV seropositivity. Cattle were selected by a two-stage cluster sampling. Blood samples were collected from 560 animals originating from 40 herds. Sera were tested for antibodies against BVDV using an indirect ELISA test. The sensitivity and specificity of the test was 97.9 and 99.7%, respectively. Risk factors regarding the herd and each animal sampled were recorded through a personal interview at the time of blood sampling. Twenty-four of the 40 herds had at least one seropositive animal. The animal true seroprevalence was estimated as 14%. The marginal logistic regression model used to describe the data found a significant (p < 0.05) association of herd size–cow-origin interaction. The interaction was due to a higher risk of seropositivity in the category of herds with ≤100 animals and purchased cows (OR = 1) as compared to herds with ≤100 animals and cows born in the farm (OR = 0.23). Seropositivity between cows purchased and cows born in the farm was similar for herd sizes of 101–196 and >196 animals. The r_e and D values were 0.17 ± 0.05 and 3.16 ± 0.57, respectively.     

Risk factors associated with Neospora caninum seropositivity in randomly sampled Canadian dairy cows and herds

Our objective was to determine cow- and herd-level risk factors associated with seropositivity for Neospora caninum in a large number of randomly selected Canadian dairy herds, controlling for important confounding variables and co-infections with bovine leukemia virus (BLV), bovine viral diarrhea virus (BVDV) and Mycobacterium avium subspecies paratuberculosis (MAP). Serum samples were obtained from 30 randomly selected cows, where available, in 240 herds using monthly milk testing, within 6 of 10 provinces, and these samples were tested for antibodies against BLV, MAP and N. caninum using commercially available ELISA test kits. Five unvaccinated cattle >6 months old from each herd were tested for antibodies to BVDV using virus neutralization. Most herd-level predictors were obtained through personal interviews with questionnaires administrated to each farm manager. A mixed logistic-regression model was built using N. caninum serostatus at the cow-level as the outcome variable, with herd as a random effect and province as a fixed effect. A BLV seropositive cow was 1.50 times more likely to be seropositive for N. caninum than a BLV-seronegative cow, and this was the only cow-level variable to remain in the final model. Regarding herd-level variables, with “no on-farm dogs” as the baseline, “presence of dogs but not known to eat placentas and/or fetuses” increased the odds of seropositivity for N. caninum by a factor of 1.66. For “presence of dogs known to eat placentas and/or fetuses”, the odds ratio (OR) was 2.75, demonstrating a dose–response relationship. “Using embryo transfer” (OR = 0.69), “asking for a BVDV-negative test before introducing an animal” (OR = 0.30), “using monensin in dry cows” (OR = 0.71), and “heifers having nose-to-nose contact with calves” (OR = 0.73) were all dichotomous variables negatively associated with seropositivity for N. caninum. “Number of milk cows on the farm” (OR = 0.99), and “area (acres) used for forage production” (OR = 0.99) were continuous variables negatively associated with N. caninum seropositivity.     

Relationship between Rainfall and Neospora caninum‐associated Abortion in Two Dairy Herds in a Dry Environment

The possible direct relationship between climate variations and abortion in Neospora caninum‐infected cows has not been studied. The objective of this study was to determine whether climate changes could be a risk factor for abortion in N. caninum‐infected cows, and was based on yearly serological screening for neosporosis and on the confirmation of N. caninum infection on aborted fetuses in two high‐producing dairy herds with a mean 27% seroprevalence of N. caninum antibodies. The final population study was comprised of 357 pregnancies in seropositive animals. Logistic regression analysis indicated no significant effects of herd, N. caninum antibody titre, climate variables during the first and third trimesters of gestation, mean and maximum temperature–humidity index values during the second trimester of gestation, and previous abortion on the abortion rate. Based on the odds ratio, a 1‐unit increase in lactation number yielded a 0.85‐fold decrease in the abortion rate. The likelihood of abortion was 1.9 times (1/0.54) lower for pregnant cows inseminated with beef bull semen compared with Holstein‐Friesian bull semen. The likelihood of abortion decreased significant and progressively by factors of 0.5, 0.41 and 0.3 for the respective classes 40–49, 30–39 and <30 rainfall mm during the second trimester of gestation (using the class ≥60 rainfall mm as reference). As a general conclusion, it seems that increased rainfall in a dry environment can compromise the success of gestation in N. caninum‐infected cows. Attempts should therefore be made to reduce environment effects during the second trimester of gestation, a period in which the immune response of cows is diminished.     

Seropositivity and risk factors for Brucella in dairy cows in urban and peri-urban small-scale farming in Tajikistan

In this cross-sectional study, we assessed and mapped the seroprevalence of brucellosis in small-scale dairy farming in an urban and peri-urban area of Tajikistan and investigated factors associated with seropositivity. As urban and peri-urban farming is both an opportunity to improve the livelihood for small-scale farmers and a potential public health hazard, studies are warranted to reveal possible peculiarities in the epidemiology of brucellosis in this type of dairy farming. In total, 904 cows of breeding age belonging to 443 herds in 32 villages were serologically tested with indirect enzyme-linked immunosorbent assay (ELISA) and positive samples confirmed with competitive ELISA. Two logistic regression models were used to investigate an association between seropositivity and risk factors at herd and individual level. The herd and individual seroprevalences were 4.1 and 2.0 %, respectively. Herds with a history of abortions were found to be associated with seropositivity [odds ratio (OR)?=?5.3; 95 % confidence interval (CI), 1.3–21.3]. Large herds with more than eight cattle were more likely to be seropositive compared to smaller herds with one to two cattle (OR?=?13.9; 95 % CI, 1.6–119). The number of calves produced per cow (indicating age) was found to be associated with seropositivity. Younger cows with one to two produced calves were less likely to be seropositive compared to older cows with more than six produced calves (OR?=?0.24; 95 % CI, 0.06–1.0). Neither introduction of new cattle to the herd nor communal grazing was associated with seropositivity. This study shows that infection with Brucella (1) is present in small-scale urban and peri-urban dairy farming in Tajikistan and (2) has significant negative effects on reproductive performance in this farming system and (3) that some previously known risk factors for seropositivity in rural farming system were absent here.     

Risk factors for Brucella spp. infection In dairy cattle farms in Asmara, State of Eritrea

A cross-sectional study was conducted to identify risk factors for herd infection by Brucella spp. in dairy cattle in the suburbs of Asmara, Eritrea. Data were collected from 64 herds, randomly selected from a total of 99 herds with a minimum herd size of 9 cows. A questionnaire was used to gather data on management, hygiene and herd structure. Serum samples collected from all pregnant heifers, cows and bulls, were screened for Brucella infection by the Rose Bengal test (RBT), and all RBT-positive sera re-tested with the complement-fixation test (CFT) for confirmation. A seropositive herd was defined as one in which at least one animal tested positive in the CFT. There were 23 (36%) positive herds among the 64 studied. Both multiple logistic and multiple betabinomial regression modeling were used to analyze the data. Mixed-breed herds, compared to single (exotic)-breed herds, were found to be independently associated with increased herd seroprevalence (OR=5.2, 95% confidence interval 1.4–18.7) in the multiple logistic model with the herd infection status as the dependent variable. The importance of this variable was supported by the multiple betabinomial regression model (OR=3.3, 1.4–7.6) with animal-level prevalence within herd as the outcome variable. Both models also revealed the presence of a negative association between seropositivity and cattle stocking density.     

Seroprevalence of Neospora caninum antibodies and its consequences for reproductive parameters in dairy cows from Dakar–Senegal,West Africa

The aim of this study was to determine the seroprevalence of Neospora caninum antibodies and its effects on reproductive parameters in cows in intensive dairy herds in Dakar. Randomised blood samples were taken for serology from 196 cows in four herds with a history of sporadic abortion. All of the sera were assayed for antibodies against N. caninum, Candida guillermondii, Coxiella burnetii, and Chlamydophila sp. The associations between serostatus and reproductive parameters (abortion, number of inseminations to conception, and calving to conception interval) were assessed over a period of 5 years (2004–2008). The seroprevalence of N. caninum antibodies in dairy cattle was 17.9%. The local Gobra breed and crossbreeds had higher levels of N. caninum antibodies than exotic breeds (p < 0.05). For the most recent pregnancies, seropositive cows required more inseminations to establish conception than seronegative cows (p < 0.05). The results indicate that dairy cattle from Dakar are exposed to N. caninum. Neosporosis should, therefore, be systematically considered as a cause when the calving to conception interval is prolonged.     

Seroprevalence of antibody to NcSAG1 antigen of Neospora caninum in cattle from Western Java,Indonesia

Neospora caninum can cause fetal abortion and neonatal mortality in cattle, and is a cause of economic concern worldwide. This study aimed to determine the prevalence of Neospora caninum-specific antibodies in cattle from Western Java, Indonesia. Serum samples from 991 cattle from 21 locations were tested for antibodies to N. caninum by using an enzyme-linked immunosorbent assay (ELISA) on the basis of recombinant NcSAG1. The overall seroprevalence was 16.6%, ranging from 0 to 87.5% in the sampled locations. The results of this study indicate latent infection rates of sampled animals were different in each location. Further studies are necessary to elucidate the relationship between N. caninum infection and abortion in cattle, and to identify risk factors for infection in high-prevalence environments.     

Seroprevalence of and risk factors for brucellosis of goats in herds of Michoacan, Mexico

Our objectives were to estimate the seroprevalence of Brucella melitensis, and to identify some risk factors associated with goat seropositivity in Michoacan, Mexico. Blood samples were collected from 5114 animals from 79 herds. Sera were tested for antibodies against B. melitensis using the Rose Bengal plate test and the complement-fixation test. Information regarding the herds and each animal sampled were recorded through a personal interview at the farm. We used random-effects multivariable logistic regression to analyze our data. Fifty-six herds of the 79 tested had at least one seropositive animal. The animal-level true seroprevalence was 9.8% (CI = 8.8, 10.7). Animals in large herds (>34 animals), in herds with high stock density (>3.5 animals/m²) or animals >24 months old had higher odds of seropositivity (2.0, 1.7 and 1.8, respectively) than those in small herds, in herds with low stock density or animals ≤24 months old.     

Increasing prevalence of Coxiella burnetii seropositive Danish dairy cattle herds

A study based on bulk tank milk samples from 120 randomly selected dairy cattle herds was conducted to estimate the prevalence of Coxiella burnetii seropositive dairy herds, to describe the geographical distribution, and to identify risk factors. Using the CHEKIT Q-fever Antibody ELISA Test Kit (IDEXX), the study revealed a prevalence of 79.2% seropositive herds, 18.3% seronegative herds, and 2.5% serointermediate herds based on the instructions provided by the manufacturer. Multifactorial logistic regression showed statistically significant associations (P < 0.01) between C. burnetii seropositivity and increasing herd size (OR = 1.02 per cow increment) and increasing regional average number of cattle per dairy herd (OR = 1.02 per animal increment). Herds >150 cows had 17.9 times higher odds of testing positive compared to herds <80 cows. The regional average number of cattle herds per square kilometer was borderline significantly related to the occurrence of seropositive dairy herds (P = 0.06). The results indicate an increased prevalence of seropositive dairy herds since the previous survey in 2008 and an adverse impact of increasing herd size and cattle density on the risk of seropositivity.