Individual animal risk factors for clinical mastitis in meat sheep in Norway

An m:n matched case–control study was conducted to identify risk factors for ovine clinical mastitis (CM). Data were from a national sheep registry and only ewes that lambed in the spring of 2004 were included. Eligible cases (n = 2857) and controls (n = 76,716) from 1056 flocks of meat sheep were matched on flock and conditional logistic regression was used for analysis of the data. CM risk was associated with age of the ewe and whether or not assistance at lambing was needed owing to dystocia; however, the effects of both these factors were modified by the number of lambs born. In ewes with 1 lamb, increasing age was associated with increased odds of CM (OR = 1.2 for each 1-year increase), while only a slight numerical increase in the odds was observed in ewes with >1 lamb. Dystocia was associated with increased odds of CM in ewes with 1 lamb (OR = 1.7) or 2 lambs (OR = 1.4), while no association was observed in ewes with >2 lambs. The odds of CM increased markedly with increasing number of lambs born to the ewe. For example, odds for 2-year-old ewes without dystocia were 6.7 times greater for those with >3 lambs than for those with 1 lamb. Compared with ewes of old Norwegian breeds, ewes of other breeds were more likely to experience CM (OR = 1.7). Ewes treated for CM at least once during the preceding 3 years had 4.0 times greater odds of CM compared with ewes without a CM history. It is likely that the effect estimates from this study, which are adjusted for breed and unaffected by inter-flock variations, are valid also for other meat sheep populations.     

Campylobacter infection in wild artiodactyl species from southern Spain: Occurrence,risk factors and antimicrobial susceptibility

A cross-sectional study was performed to assess the occurrence of Campylobacter species and to identify potential associated risk factors for wild artiodactyl species in southern Spain. Campylobacter species were isolated in 55 of 363 (15.2%) faecal samples. Campylobacter was identified in faeces from wild boar (49/126; 38.9%), red deer (5/179; 2.8%) and mouflon (1/13; 7.7%) but not from fallow deer (0/45). The isolated Campylobacter species were identified as C. jejuni (2 isolates; 3.6%), C. coli (11 isolates; 20.0%) and C. lanienae (37 isolates; 67.3%). Five isolates (9.1%) could not be identified at the species level. This report is the first to describe C. lanienae infection in wild ruminant species. Resistance to erythromycin (4.8%), ciprofloxacin (37.5%), tetracycline (52.9%) and streptomycin (55%) were detected. C. lanienae presented a significantly higher number of susceptible isolates to ciprofloxacin and tetracycline than C. coli. Due to the low number of positive wild ruminants, a Generalised Estimating Equations model was only carried out for wild boar. The model indicated that the risk factors associated with Campylobacter infection were the density of wild boar (>10/100 ha) (OR: 3.05; CI_95%: 2.2–4.3), the presence of artificial waterholes (OR: 3.67; CI_95%: 1.3–10.5) and the winter season (OR: 3.30; CI_95%: 1.9–5.8). Campylobacter infection is widespread in wild boar populations in southern Spain. These findings suggest that wild artiodactyls, particularly wild boar, constitute a reservoir of Campylobacter species, including resistant and multi-resistant strains, which may be of public health concern.     

Prevalence and risk factors of Campylobacter infection in broiler flocks from southern Spain

An extensive epidemiological study was performed to determine the prevalence and risk factors of Campylobacter infection in broiler farms in Andalusia (southern Spain). A total of 2221 cloacal swabs and 747 environmental swabs from 291 broiler flocks were screened between April 2010 and May 2012. The prevalence of Campylobacter in individual animals was 38.1%, and the flock prevalence was 62.9%. Flocks were predominantly infected by C. jejuni and C. coli but were also infected by untyped Campylobacter spp., and mixed-species infection could be found. Risk factors for Campylobacter infection were assessed from direct interview of the farmers. The number of positive samples by flock was modelled assuming a binomial distribution. Analysis indicated five factors associated with increased intra-flock prevalence: presence of dogs or cats on the farm, older age of the broiler flock, the application of thinning of flocks, the presence of windows with canvas blinds, and the presence of rodents in the poultry house. Two factors were associated with decreased intra-flock prevalence: the treatment of drinking water and having an entrance room for access into the poultry house. This is the first study performed on broilers farms from Spain reporting the risk factors of Campylobacter infection and is the largest study on the prevalence of Campylobacter infection.     

Hydatidosis of sheep and goats slaughtered at Addis Ababa Abattoir: prevalence and risk factors

Abattoir survey was conducted on 1,053 sheep and 639 goats slaughtered at Addis Ababa Abattoir, Ethiopia, between October 2007 and May 2008, with the objective to determine the prevalence of hydatidosis and assess the associated risk factors. Routine meat inspection procedure was employed to detect the presence of the cyst in visceral organs (lung, liver, and omentum). Hydatid cysts were found in 206 (19.94%) and 102 (16%) of the sheep and goats inspected, respectively. Statistically significant difference in infection rates was noted between the two species. Likewise, there was significant difference in infection rates between the two sexes and different age groups in both sheep and goats (P < 0.5). The study showed that hydatidosis is prevalent in Ethiopia. Thus, there is a need to introduce appropriate control measures to minimize the rate of infection and reduce the ensuing economic losses.     

Occurrence and risk factors associated to Toxoplasma gondii infection in sheep from Rio de Janeiro,Brazil

Toxoplasmosis is an important cause of abortion in sheep and a zoonotic risk to humans, leading to significant hazards to health and to economic losses. This study examined the seroprevalence and associated risk factors for infection with Toxoplasma gondii in 379 sheep from 12 flocks in Rio de Janeiro state, Brazil. Using the modified agglutination test (MAT), 202 (53.3 %) of 379 were seropositive with titers of 1:25 in 65, 1:50 in 40, 1:100 in 23, 1:200 in 11, 1:400 in 36, 1:800 in 7, 1:1,600 in 1, and 1:3,200 or higher in 19 sheep. The most significant factors associated with T. gondii seropositivity in sheep were age, gender, and veterinary care. Finding of T. gondii antibodies in 97 of the 202 sheep in titers of 1:100 or higher is indicative of persistently infected animals. This high level of seropositivity requires urgent control measures to reduce impact on animal productivity and public health.     

Seroprevalence and risk factors associated with Neospora caninum infection in different dog populations in Spain

In this study, Neospora caninum seroprevalence and some associated risk factors were investigated in four different dog populations in Spain. N. caninum seropositivity was significantly higher in farm dogs (51%, 51/100) (P<0.001) and lower in household dogs (2.9%, 3/102) (P<0.0001). The seroprevalence in hunting (23%, 23/100) and stray (24.5%, 23/94) dogs was moderate, and no significant differences were observed between these two populations (P>0.05). A significantly higher number of dogs showed titres of 1:50-1:100 (68%, 68/100) than >or=1:200 (33%, 33/100) titres (P<0.0001). N. caninum antibodies were more often detected in mixed breed than pure breed dogs (P<0.01), but when data were stratified by dog type a significant association was not found (P>0.05). A significantly higher prevalence of N. caninum was observed in dogs over 1 year old (P<0.01), indicating that horizontal transmission may be the most important route of infection. The presence of N. caninum antibodies was significantly more frequent in Leishmania infantum-seropositive hunting (P<0.05) and stray dogs (P<0.00001). This study confirms that farm, stray and hunting dogs can be considered at-risk dog populations for N. caninum infection in Spain.     

Seroprevalence and risk factors associated with Toxoplasma gondii infection in pig farms from Catalonia, north-eastern Spain

Seroprevalence and associated risk factors for Toxoplasma gondii infection in pigs were analyzed in 1202 sera samples, including sows and pigs of three, seven, 11, 15 and 20 weeks of age, from 23 farms in Catalonia, north-eastern Spain. Antibodies were tested by the modified agglutination test (MAT) at titers ?1:25. Antibodies to T. gondii were found in 228 samples (19.0%; 95% CI: 16.8-21.2). The individual prevalence in animals higher than 7 weeks of age was 22.8% (174/762; 95% CI: 16.6-29.0) and the within-farm prevalence ranged from 7.1% to 36.4%. Statistically significant differences were found among age classes. The risk factors significantly associated with T. gondii seroprevalence were the presence of cats, percentage of mortality at weaning and the presence of outdoor facilities in the farms. The seroprevalence observed in the present study indicates widespread exposure to T. gondii among domestic pigs in Catalonia, which may have important implications for public health.     

The prevalence of salmonella infection in sheep at slaughter

The prevalence of subclinical Salmonella infection in sheep at slaughter was monitored at two slaughter-houses in the southern part of the North Island over a 17-month period during 1975 and 1976. The crude prevalence rate was 4.7% (96/2027). Prevalence rates were greatest in the 2 and 4-tooth age group, with maximum monthly rates of 30%and 32% during 1975 and 1976 respectively. The seasonal distribution of infections was similar in each age group, prevalence rates being greatest in March, April and May, and least in October, November and December.

Salmonella typhimurium was found in 78% of the infected sheep, and phage-type 1 caused 72% of these infections. Other serotypes isolated were S. bovis-morbificans, S. derby, S. newingion, S. saintpaul, S. anatutn and S. enieritidis. The organisms were all fully sensitive to nine antibiotics. On the grounds that 87% of the infected sheep had salmonellae in their intestinal lymph nodes, it was deemed likely that most of the infected sheep harboured their infections while still on the farms of origin.     

Cross-sectional survey on Toxoplasma gondii infection in cattle, sheep and pigs in Serbia: seroprevalence and risk factors

Toxoplasmosis is a globally distributed zoonosis with a clinical impact in the unborn fetus and in the immunosuppressed individual. In Serbia, studies of risk factors for Toxoplasma gondii infection in humans have shown that the relatively high prevalence is associated mainly with consumption of undercooked meat and/or meat products. However, data on T. gondii infection in domestic animals mostly used for human consumption are scarce. We thus conducted a cross-sectional survey on the seroprevalence of T. gondii infection in a representative sample of cattle, sheep and pigs from different regions of Serbia between June 2002 and June 2003, and analyzed the main risk factors associated with the infection. Sera from 611 cattle (yearlings and adults of both sexes), 511 ewes, and 605 pigs (market-weight and sows), were examined for T. gondii antibodies by the modified agglutination test. The seroprevalences determined were 76.3% in cattle, 84.5% in sheep and 28.9% in pigs. The antibody levels ranged from 1:25 to 1:400 in cattle, and up to 1:25,600 in sheep and to 1:12,800 in pigs. Among the seropositive, the proportion of high antibody levels (> or =1:1600), suggestive of acute infection, was 10% in sheep, and 4% in pigs. Possible association of the infection with biologically plausible risk factors including gender, age, herd size/farm type, type of housing, feeding practices and region, was analyzed by univariate analysis, and variables significant at P< or =0.1 were included in multivariate logistic regression models. The results showed that risk factors for cattle were small herd size (odds ratio, OR=2.19, 95% confidence interval, CI=1.28-3.75, P=0.004) and farm location in Western Serbia (OR=2.04, 95% CI=1.10-3.79, P=0.024), while housing in stables with access to outside pens was protective (OR=0.37, 95% CI=0.21-0.67, P=0.001). In sheep, an increased risk of infection was found in ewes from state-owned flocks (OR=4.18, 95% CI=2.18-8.00, P<0.001) vs. private flocks, and, interestingly, also in those from Western Serbia (OR=4.66, 95% CI=1.18-18.32, P=0.028). In pigs, the risk of infection was highly increased in adult animals (OR=3.87, 95% CI=2.6-5.76, P<0.001), as well as in those from finishing type farms (OR=3.96, 95% CI=1.97-7.94, P<0.001). In addition to providing data on the current T. gondii seroprevalence in meat animals in Serbia, the results of this study show the main risk factors associated with infection, thereby pointing to the type of preventive measures to reduce T. gondii infection.     

Endemic sheep scab: risk factors and the behaviour of upland sheep flocks

Since the deregulation of sheep scab in 1992, the number of scab outbreaks per year in the UK has increased rapidly; there has been an estimated 60-fold increase in outbreak incidence between 1992 and 2007. How best to focus management or eradication efforts has therefore been an issue of ongoing debate. Previous work has shown that scab outbreaks occur repeatedly on some farms whereas others never or rarely experience outbreaks. Here, to consider why this pattern occurs, and to quantify the risk of scab associated with different husbandry practices, face-to-face interviews with farmers at 16, randomly selected, repeat-outbreak farms and 16 matched farms with no or little history of scab over the previous 10 years, were used to identify associated risk factors. This showed that farms using common grazing were at significantly higher risk of infestation than farms not using common grazing, as were farms that had direct contact with neighbours' sheep and that had neighbours with scab. To further demonstrate the risk of common grazing, a survey of sheep on one common in south Wales showed that there was significant mixing of sheep from three farms, highlighting the potential for scab transmission between flocks. Common grazing, associated with upland regions, would appear to be the largest single obstacle to effective national scab control in the UK. The results suggest that a cost-effective approach to scab control may be to consider upland and lowland farms as separate epidemiological systems, with upland regions requiring a co-ordinated, systematic approach to achieve any significant management of the problem. In contrast, on lowland farms outbreaks are already largely contained effectively through good biosecurity and treated on a case-by-case basis if they occur.     

Farm-level risk factors for the occurrence,new infection or persistence of tuberculosis in cattle herds from South-Central Spain

Eradication of tuberculosis (TB) in cattle is a priority in the EU. However, and despite the resources invested, TB eradication is still a goal yet to be accomplished. As a consequence, the identification of risk factors contributing to TB transmission and persistence is key to a better understand and, ultimately, more cost-effectively control and eradicate this complex zoonotic disease worldwide. This study aimed to identify the factors contributing to the TB occurrence, new infection, and persistence in one of the most TB-prevalent regions in the South-Central part of Spain (SCS), Ciudad Real (CR), and for which high quality and detailed information on cattle and wild ungulate demographics, management, and sanitary status was available for up to 5 years (2007–2011). Multilevel logistic modeling was used for this purpose. Results of this study revealed that the risk for TB (occurrence, new infection, and/or persistence) in cattle herds from CR is related to TB-persistence on farm in previous years, extensive production systems (beef and bullfighting being more risky that dairy) and large farm in terms of cattle number. Also, the presence and proximity of fenced hunting estates (which are usually intensively managed) significantly contributed to the risk of TB occurrence and persistence in CR. This association suggests that wild ungulates may play a role as TB-reservoirs and transmit TB to cattle in the CR, a region where TB is endemic and is associated with extensive farming of beef cattle. To the best of author's knowledge this is the first study to (i) evaluate the wild ungulate-domestic interface at a farm level using detailed information over an extensive region and period of time (2007–2011) and (ii) to identify a direct association between TB in cattle and the proximity and management practices of wild ungulates. Methods and results presented here may support policies to better prevent and control TB in the SCS and in other regions/countries with similar epidemiological conditions.     

Seroprevalence and risk factors associated with neosporosis in sheep and dogs from farms

This study aimed to establish the seroprevalence and risk factors associated with neosporosis in sheep and dogs from rural properties. 1497 blood samples were collected from sheep and 42 from dogs that cohabited with sheep from 16 farms located in the central region of S?o Paulo State, Brazil. For the detection of N. caninum antibodies it was performed the indirect fluorescent antibody test (IFAT ≥ 25). For the epidemiological study it was applied a questionnaire for the owners or responsible from the sheep and dogs regarding informations related to neosporosis. The seroprevalence obtained out of the 1497 sheep sera tested was 8.0% (CI95%=6.7-9.2%) and out of the 42 dogs 4.8% (CI95%=0-7.2%). Variables statistically related to seropositivity for N. caninum in sheep were: dams well as water supply (P=0.0004; OR=2.15), presence of other domestic canids (P=0.0013; OR=2.38) and presence of reproductive problems (P=0.0031; OR=1.75).     

Seroprevalence and risk factors of swine influenza in Spain

Swine influenza is caused by type A influenza virus. Pigs can be infected by both avian and human influenza viruses; therefore, the influenza virus infection in pigs is considered an important public health concern. The aims of present study were to asses the seroprevalence of swine influenza subtypes in Spain and explore the risk factors associated with the spread of those infections. Serum samples from 2151 pigs of 98 randomly selected farms were analyzed by an indirect ELISA for detection of antibodies against nucleoprotein A of influenza viruses and by the hemagglutination inhibition (HI) using H1N1, H1N2 and H3N2 swine influenza viruses (SIV) as antigens. Data gathered in questionnaires filled for each farm were used to explore risk factors associated with swine influenza. For that purpose, data were analyzed using the generalized estimating equations method and, in parallel by means of a logistic regression. By ELISA, 92 farms (93.9%; CI(95%): 89.1-98.7%) had at least one positive animal and, in total, 1340/2151 animals (62.3%; CI(95%): 60.2-64.3%) were seropositive. A total of 1622 animals (75.4%; CI(95%): 73.6-77.2%) were positive in at least one of the HI tests. Of the 98 farms, 91 (92.9%; CI(95%): 87.7-98.1%) had H1N1 seropositive animals; 63 (64.3%; CI(95%): 54.6-73.9%) had H1N2 seropositive pigs and 91 (92.9%; CI(95%): 87.7-98.1%) were positive to H3N2. Mixed infections were detected in 88 farms (89.8; CI(95%): 83.7-95.9%). Three risk factors were associated with seroprevalences of SIV: increased replacement rates in pregnancy units and, for fatteners, existence of open partitions between pens and uncontrolled entrance to the farm.     

Airway inflammation in Michigan pleasure horses: prevalence and risk factors

REASONS FOR PERFORMING STUDY: Although subclinical airway inflammation is thought to be common in horses, there is little information on its prevalence and none on risk factors. OBJECTIVE: To determine the prevalence and risk factors for an increased number of inflammatory cells and for mucus accumulation in the trachea of pleasure horses. METHODS: Horses (n = 266) in stables (n = 21) in Michigan were examined endoscopically, once in winter and once in summer 2004. Visible tracheal mucoid secretions were graded 0-5 and inflammatory cell numbers counted in a tracheal lavage sample. Information collected about each horse included age, gender, presence of cough, percent time indoors and source of roughage. The repeated measures were analysed by generalised estimating equations and linear mixed models. RESULTS: Horses eating hay, especially from round bales, had the most neutrophils, whereas horses feeding from pasture had the fewest. Being female and being outdoors in winter were associated with increased numbers of inflammatory cells. Older horses had fewer macrophages than young horses. More than 70% of horses had >20% neutrophils in tracheal lavage. Twenty percent of horses had a mucus accumulation score >1; 17% had both a mucus score >1 and >20% neutrophils. The significant risk factors for mucus accumulation >1 were age >15 years, feeding on hay as compared to pasture, and being outdoors for more than 80% time in winter. Even though mucus accumulation score >1 was a risk factor for cough, only half of such horses coughed. Cough and mucus accumulation were associated with increased number of neutrophils. CONCLUSIONS: In comparison to pasture feeding, hay feeding, particularly from round bales, was associated with an increased number of neutrophils in the airway. Being outdoors in winter was associated with increased numbers of inflammatory cells and with mucus accumulation. Because 70% of horses have >20% neutrophils, this value should not be used as the sole indicator of airway inflammation. POTENTIAL RELEVANCE: The study reinforces the importance of hay feeding and older age as risk factors for inflammatory airway disease. Horses that do not have 'heaves' may be best kept indoors when winters are cold.     

Determination of prevalence and risk factors of infection with Babesia in small ruminants from Greece by polymerase chain reaction amplification

A total of 124 blood samples were collected from 92 sheep and 32 goats from 21 randomly selected herds located in two regions of Greece. Data on the characteristics of the animals (species, gender, age, tick burden, presence of haemoglobinuria, prior treatment for babesiosis) and the herd (location, size, species of animals, dogs associated with the herds, tick burden of dogs associated with the herds) were collected through questionnaires. Nineteen animals (15%) produced the DNA fragment specific for Babesia of which 16 were sheep and three were goats. Nucleotide sequence of PCR products revealed 100% homology with Babesia ovis 18S rRNA gene. Nine farms (43%) were found positive for B. ovis. The percentage of positive animals in each farm varied between 10 and 61%. The relative risk of the presence of ticks in sheep and goats (p<0.01) and farm dogs (p<0.01) for PCR-positive results for B. ovis in sheep and goats was found 6.63 and 4.14, respectively.     

Risk factors associated with the prevalence of footrot in sheep from 1999 to 2000

A postal survey of the techniques being used for the treatment and control of footrot in sheep flocks between November 1999 and October 2000 was conducted in England and Wales in November 2000. Of the 392 questionnaires circulated, 251 (64 per cent) were returned, and 209 of these were usable. Negative binomial regression analysis indicated that the isolation of bought-in sheep, and the separation and individual treatment of diseased sheep with parenteral antibiotics, foot trimming and topical foot sprays were associated with a significantly lower prevalence of footrot in a flock. In contrast, ewe flocks which were routinely foot trimmed more than once a year had a significantly higher prevalence of footrot. No evidence was found that footbathing a flock reduced the level of footrot, except on the 14 per cent of farms where the penning and race facilities for footbathing were reported by the farmer to be excellent. Vaccination had no significant beneficial effect on the level of footrot in a flock     

Risk factors for brucellosis seroprevalence of sheep and goat flocks in Spain

Risk factors for ovine and caprine brucellosis in the Ávila region (center of Spain) were evaluated using data from a cross-sectional study of the most important diseases of small ruminants in this Spanish region between 1996 and 1997. Questionnaire data from 56 herds (35 ovine and 21 caprine) were used. Sixteen (29%) flocks (3 caprine and 13 ovine) were brucellosis-seropositive. Overall, 0.7% of sheep and 0.1% of goats were seropositive. Eleven risk factors were studied at the group level by logistic regression using flock brucellosis-status as outcome, and by linear regression using percentage of brucellosis-seropositivity as outcome. Both final models contained the same variables: contact with sheep and grazing in communal pastures as risk factors, and frequency of disinfecting practices as a protective factor.     

Risk factors associated with the prevalence of interdigital dermatitis in sheep from 1999 to 2000

As part of an investigation into improving the treatment and control of lameness in sheep flocks in England and Wales, a postal survey was conducted in November 2000. Farmers were asked to estimate the prevalence of footrot and interdigital dermatitis in their flocks. In the ewes the prevalence of interdigital dermatitis remained relatively stable throughout the year, but there was a large increase in lambs during late spring and early summer. Logistic regression models were used to assess statistically significant risk factors associated with prevalences of the condition of 5 per cent or more in ewes and 10 per cent or more in lambs. Factors that increased the risk in ewes were 'sometimes/never' catching lame sheep compared with 'always' farm land 100 m or less above sea level and renting-in winter grazing; factors that increased the risk in lambs were a prevalence of 5 per cent or more of footrot in ewes, 'sometimes/never' catching lame ewes compared with 'always', 'sometimes/never' treating ewes with footrot with parenteral antibiotics compared with 'always', showing sheep at agricultural events, farm land 100 m or less above sea level, and a prevalence of 5 per cent or more of interdigital dermatitis in ewes. Turning sheep on to a field which had been free from livestock for at least two weeks after footbathing decreased the risk of interdigital dermatitis in lambs. Footbathing without the use of a clean field compared with not footbathing did not significantly affect the prevalence of the interdigital dermatitis.