Evaluation of risk factors of omphalitis in newborn beef calves with indoor housing.

BACKGROUND: Omphalitis is the third most common cause for diseases and infections in newborn calves. Its risk factors are well described in dairy production, but data in beef production is limited. OBJECTIVE: To identify and quantify the risk factors of omphalitis in cow-calf operations with seasonal indoor calving period. ANIMALS: Nine hundred sixty-four calves included from 22 cow-calf operations in central France were included. METHODS: A prospective cohort study involved data collection during two visits for each calf. Simple and multivariable logistic regression analyses evaluated the association between omphalitis and the variables. RESULTS: Among 964 included calves, 311 (32.3%) calves had an omphalitis. Accounting for farms' random effect, risk factors for omphalitis highlighted by the univariable analysis were: absence of navel disinfection (odds ratio (OR) = 2.3, [1.45-3.04]), wetness of bedding calving area (OR = 1.8-2.1, [0.78-2.83]-[0.63-3.57]), cleanliness of calves' pen (OR =1.6-2.8, [1.22-2.27]-[2.02-3.84]), wetness of calves' pen bedding (OR = 1.7-3.2, [1.12-2.06]-[3.08-3.84]), calf weight at birth >50 kg (OR = 2.0-5.0, [1.02-2.38]-[1.51-11.1]), umbilical cord length <3 cm (OR = 2.2-2.3, [1.53-3.11]-[1.24-4.38]), and sex (male vs female) (OR = 2.6, [2.08-3.69]). The multivariable analysis, accounting for farms' random effect, showed that the absence of navel disinfection (OR= 2.2, [1.44-3.09]), wetness of bedding calving area (OR = 1.9-2.4, [0.55-2.83]-[0.59-3.28]), calf weight at birth >50 kg (OR = 1.9-2.6, [1.03-2.56]-[1.43-12.5]) and sex (male vs female) (OR =2.4, [2.09-3.49]) were risk factors for omphalitis. CONCLUSIONS AND CLINICAL IMPORTANCE: These observations may help identify animals at early risk (>50 kg, male, short umbilical cord) and pay particular attention to the wetness of bedding and cleanliness of housing. This study highlights the importance of calving-pen bedding, calf characteristics and navel disinfection.

Failure of Passive Immunity Transfer Is Not a Risk Factor for Omphalitis in Beef Calves.

Omphalitis is the third most frequent disease in newborn calves after neonatal diarrhea and bovine respiratory disease (BRD), but limited data on the prevalence and risk factors are available in the literature. Failure of passive immunity transfer (FPIT) is recognized as a major risk factor for diseases and mortality in calves. However, the association between omphalitis and FPIT remains poorly described. To assess this association, 964 suckler beef calves from 22 farms were included in a longitudinal cohort study for 5 months. Each calf was examined twice (mean ages: 4.4 and 11.1 days old) to diagnose omphalitis through clinical examination and ultrasonographic evaluation (USE) if necessary. Measurements of the total solids percentage (TS-%Brix) and total protein (TP) were performed on the serum during the first visit to evaluate the calves' passive immunity status. FPIT (fair and poor) was defined as serum %Brix < 8.1 or TP < 5.1 g/dL; among calves with omphalitis, 14% had FPIT and among calves without omphalitis 12% had FPIT. The omphalitis prevalence was 32.3% in calves without any other disease (overall prevalence of 30.9%). No statistical association between the prevalence of omphalitis and FPIT was observed. Further research is needed to identify the risk factors and promote the prevention measures for omphalitis in cow-calf systems, such as calving difficulty, hygiene of housing, and navel disinfection.

One Health surveillance of West Nile and Usutu viruses: a repeated cross-sectional study exploring seroprevalence and endemicity in Southern France, 2016 to 2020.

BackgroundWest Nile virus (WNV) and Usutu virus (USUV), two closely related flaviviruses, mainly follow an enzootic cycle involving mosquitoes and birds, but also infect humans and other mammals. Since 2010, their epidemiological situation may have shifted from irregular epidemics to endemicity in several European regions; this requires confirmation, as it could have implications for risk assessment and surveillance strategies.AimTo explore the seroprevalence in animals and humans and potential endemicity of WNV and USUV in Southern France, given a long history of WNV outbreaks and the only severe human USUV case in France in this region.MethodsWe evaluated the prevalence of WNV and USUV in a repeated cross-sectional study by serological and molecular analyses of human, dog, horse, bird and mosquito samples in the Camargue area, including the city of Montpellier, between 2016 and 2020.ResultsWe observed the active transmission of both viruses and higher USUV prevalence in humans, dogs, birds and mosquitoes, while WNV prevalence was higher in horses. In 500 human samples, 15 were positive for USUV and 6 for WNV. Genetic data showed that the same lineages, WNV lineage 1a and USUV lineage Africa 3, were found in mosquitoes in 2015, 2018 and 2020.ConclusionThese findings support existing literature suggesting endemisation in the study region and contribute to a better understanding of USUV and WNV circulation in Southern France. Our study underlines the importance of a One Health approach for the surveillance of these viruses.

Molecular assessment of Theileria equi and Babesia caballi prevalence in horses and ticks on horses in southeastern France.

Equine piroplasmosis (EP) is a tick-borne disease caused by Babesia caballi and Theileria equi that is potentially emerging in non-endemic countries. We conducted a descriptive study to investigate EP prevalence and spatial distribution in an endemic region: the Camargue and the Plain of La Crau in France. In spring 2015 and 2016, we carried out sampling at stables (total n = 46) with a history of horses presenting chronic fever or weight loss. Overall, we collected blood from 632 horses, which were also inspected for ticks; these horses had been housed in the target stables for at least 1 year. We obtained 585 ticks from these horses and described land use around the stables. Real-time PCR was employed to assess T. equi and B. caballi prevalence in the horses and in the ticks found on the horses. For the horses, T. equi and B. caballi prevalence was 68.6% and 6.3%, respectively. For the ticks found on the horses, prevalence was 28.8% for T. equi and 0.85% for B. caballi. The most common tick species were, in order of frequency, Rhipicephalus bursa, R. sanguineus sl., Hyalomma marginatum, Haemaphysalis punctata, and Dermacentor sp. Horses bearing Rhipicephalus ticks occurred in wetter zones, closer to agricultural areas, permanent crops, and ditches, as well as in drier zones, in the more northern countryside. Compared to horses bearing R. bursa, horses bearing R. sanguineus sl. more frequently occurred near the Rhone River. Prevalence of T. equi in the ticks was as follows: Hyalomma marginatum (43%), Dermacentor sp. (40%), R. bursa (33%), R. sanguineus sl. (19%), and Haemaphysalis punctata (17%). In contrast, B. caballi only occurred in Dermacentor sp. (20%) and R. bursa (1%).

Seroprevalence of horses to Coxiella burnetii in an Q fever endemic area.

Coxiella burnetii can infect many animal species, but its circulation dynamics in and through horses is still unclear. This study evaluated horse exposure in an area known to be endemic for ruminants and humans. We assessed antibody prevalence in horse serum by ELISA, and screened by qPCR horse blood, ticks found on horses and dust from stables. Horse seroprevalence was 4% (n = 335, 37 stables) in 2015 and 12% (n = 294, 39 stables) in 2016. Of 199 horses sampled both years, 13 seroconverted, eight remained seropositive, and one seroreverted. Seropositive horses were located close to reported human cases, yet none displayed Q fever-compatible syndromes. Coxiella DNA was detected in almost 40% of collected ticks (n = 59/148 in 2015; n = 103/305 in 2016), occasionally in dust (n = 3/46 in 2015; n = 1/14 in 2016) but never in horse blood. Further studies should be implemented to evaluate if horses may be relevant indicators of zoonotic risk in urban and suburban endemic areas.

One particular Anaplasma phagocytophilum ecotype infects cattle in the Camargue, France.

BACKGROUND: Anaplasma phagocytophilum is a zoonotic tick-borne pathogen responsible for granulocytic anaplasmosis, a mild to a severe febrile disease that affects man and several animal species, including cows and horses. In Europe, I. ricinus is the only proven vector for this pathogen, but studies suggest that other tick genera and species could be involved in its transmission. Our objective was to assess the presence and genetic diversity of A. phagocytophilum in domestic animals and different tick species from the Camargue region, located in the south of France. METHODS: A total of 140 ticks and blood samples from 998 cattle and 337 horses were collected in Camargue and tested for the presence of A. phagocytophilum DNA by msp2 quantitative real-time PCR. Molecular typing with four markers was performed on positive samples. RESULTS: Anaplasma phagocytophilum DNA was detected in 6/993 (0.6%) cows, 1/20 (5%) Haemaphysalis punctata, 1/57 (1.75%) Rhipicephalus pusillus, and was absent in horses (0%). All cattle A. phagocytophilum presented a profile identical to an A. phagocytophilum variant previously detected in Dermacentor marginatus, Hyalomma marginatum, and Rhipicephalus spp. in Camargue. CONCLUSIONS: Our results demonstrate that one particular A. phagocytophilum variant infects cattle in Camargue, where I. ricinus is supposed to be rare or even absent. Dermacentor marginatus, Rhipicephalus spp. and Hyalomma spp., and possibly other tick species could be involved in the transmission of this variant in this region.

Molecular epidemiology of Coxiella burnetii in French livestock reveals the existence of three main genotype clusters and suggests species-specific associations as well as regional stability.

Q fever is a worldwide zoonosis caused by the bacterium Coxiella burnetii. In domestic ruminants, Q fever main clinical manifestations are abortions. Although the clinical signs may differ between ruminant species, C. burnetii's genetic diversity remains understudied in enzootic areas. Here, we focused on France, where Q fever is enzootic, with the aims to (a) identify potential associations between C. burnetii genotypes and ruminant host species; (b) assess the distribution of C. burnetii genotypes both within French farms and across France's major livestock-farming regions; and (c) suggest a subset of markers for future genotypic studies. We used DNA samples collected between 2006 and 2015 from 301 females (160 cows, 76 ewes, 65 goats) aborted of Q fever within 7 different farming regions. C. burnetii diversity was determined using a multiple-locus variable-number of tandem repeat analysis (MLVA) considering 17 markers. Using a phylogenetic approach, we identified 3 main genotypic clusters divided into 12 sub-clusters. These clusters were significantly associated with ruminant species: almost all the cattle genotypes were found in a "cattle-specific" cluster whereas small ruminants genotypes essentially grouped into the two other clusters. The clusters also proved stable over space and time, some genotypes being more specifically observed in certain farming regions. We also observed some within-farm diversity but this diversity was restricted to a same genotypic cluster. Finally, we identified 6 MLVA markers that maximized the representativeness of the diversity described. Overall, we highlighted that molecular epidemiology is a relevant approach to assess C. burnetii's genetic diversity and to reveal the existence of species-specific associations and regional stability. These results will be valuable in the field to trace genotype circulation among ruminants and from ruminants to humans. Ultimately, the potential links between genotypes and virulence traits need to be investigated to adapt control measures in livestock farms.

Impact of IS1111 insertion on the MLVA genotyping of Coxiella burnetii.

Q fever epidemiological investigations of the likely sources of contamination may involve Coxiella burnetii MLVA for direct and rapid typing from clinical samples. However, little information is available with regards to PCR amplification failures in C. burnetii MLVA typing. This paper focuses on difficulties encountered with MLVA loci that may impact the interpretation of MLVA data and shows that some loci may constitute hotspots for mutational events. MLVA genotyping, using 17 different loci, was used on vaginal swabs (VS) from clinically infected animals as described elsewhere (Chmielewski et al., 2009). Amplicons of interest were sequenced and identified using the BLAST software by comparison with sequences available in GenBank. All VS samples produced MLVA patterns. However, amplification failures or unexpected sizes amplicons (>to 1.5 kbp), making the interpretation of MLVA complicated, were also observed. Sequencing of these amplicons revealed the presence of IS1111 element insertion. In this C. burnetii MLVA study some difficulties encountered with genotyping are highlighted and the role of IS1111 element in genome plasticity is confirmed. Finally, the need for the selection of a set of VNTRs for an efficient MLVA scheme and the question of standardization and harmonization for comparable MLVA typing data are raised again.