Temporal and spatial analysis of psittacosis in association with poultry farming in the Netherlands, 2000-2015.

BACKGROUND: Human psittacosis is a highly under diagnosed zoonotic disease, commonly linked to psittacine birds. Psittacosis in birds, also known as avian chlamydiosis, is endemic in poultry, but the risk for people living close to poultry farms is unknown. Therefore, our study aimed to explore the temporal and spatial patterns of human psittacosis infections and identify possible associations with poultry farming in the Netherlands. METHODS: We analysed data on 700 human cases of psittacosis notified between 01-01-2000 and 01-09-2015. First, we studied the temporal behaviour of psittacosis notifications by applying wavelet analysis. Then, to identify possible spatial patterns, we applied spatial cluster analysis. Finally, we investigated the possible spatial association between psittacosis notifications and data on the Dutch poultry sector at municipality level using a multivariable model. RESULTS: We found a large spatial cluster that covered a highly poultry-dense area but additional clusters were found in areas that had a low poultry density. There were marked geographical differences in the awareness of psittacosis and the amount and the type of laboratory diagnostics used for psittacosis, making it difficult to draw conclusions about the correlation between the large cluster and poultry density. The multivariable model showed that the presence of chicken processing plants and slaughter duck farms in a municipality was associated with a higher rate of human psittacosis notifications. The significance of the associations was influenced by the inclusion or exclusion of farm density in the model. CONCLUSIONS: Our temporal and spatial analyses showed weak associations between poultry-related variables and psittacosis notifications. Because of the low number of psittacosis notifications available for analysis, the power of our analysis was relative low. Because of the exploratory nature of this research, the associations found cannot be interpreted as evidence for airborne transmission of psittacosis from poultry to the general population. Further research is needed to determine the prevalence of C. psittaci in Dutch poultry. Also, efforts to promote PCR-based testing for C. psittaci and genotyping for source tracing are important to reduce the diagnostic deficit, and to provide better estimates of the human psittacosis burden, and the possible role of poultry.

The effect of double nursing, an alternative nursing strategy for the hyper-prolific sow herd, on herd performance.

BACKGROUND: Hyper-prolific sows produce more piglets than they can suckle, as the number of milk producing teats of the sow is lower (twelve to sixteen) than the number of live born piglets per litter. Farmers and farm workers are struggling to feed this surplus of piglets. To minimize suckling piglet mortality, litter size at 24 hours after parturition should not exceed the number of functional teats of the sow. Strategies to adequately nurse or feed the surplus of piglets after 24 hours are limited and mostly restricted to either fostering piglets by other sows, supplying milk replacers (formula) or early weaning and rearing on formula. CASE PRESENTATION: In this case report we describe the design and application of a so called 'double nursing' strategy, for which one sow simultaneously nurses two litters from birth to weaning. Piglet mortality and reproductive parameters of sows that have nursed two litters are compared, over a three year period, with those that nursed one litter. CONCLUSION: In this herd, the double nursing strategy appeared to be a successful strategy. Double nursing sows experienced a lower piglet mortality, despite the double nursing strategy. The negative effects on reproduction proved to be limited, there was a negative effect on litter size in subsequent litters, but no significant effect on the interval weaning to next conception. It has to be noted though that not all characteristics on which double nursing selection takes place, could be taken into account during statistical analyses.

Dutch dairy farmers' need for microbiological mastitis diagnostics.

Although several microbiological mastitis diagnostic tools are currently available, dairy farmers rarely use them to base treatment decisions on. In this study, we conducted a telephone interview among 195 randomly selected Dutch dairy farmers to determine their current use of and their need for microbiological diagnostics for clinical mastitis (CM), subclinical mastitis (SCM), and dry-cow treatment (DCT), followed by the test characteristics they consider important. A structured questionnaire was used, based on face-to-face interviews previously held with other farmers. The answers were registered in a database and analyzed using descriptive statistics and univariable and multivariable models. Antimicrobial treatment decisions for CM, SCM, and DCT were mainly based on clinical signs and somatic cell count. In case of CM, 34% of farmers indicated that they currently submit milk samples for bacteriological culture (BC). This would increase to 71% if an on-farm test resulting in treatment advice within 12 h were available. For SCM, use would increase from 22 to 55%, and for DCT, from 7 to 34%, if the same 12-h test were available. For CM and DCT, the preferred test outcome was advice on which antibiotic to use, according to 58 and 15% of the farmers, respectively. For SCM, the preferred test outcome was the causative bacterium for 38% of the farmers. Farmers who currently submit CM milk samples for BC were 13.1 times more likely to indicate, as the preferred test outcome, advice on which antibiotic to use, compared with farmers who do not currently submit CM milk samples for BC. Fourteen percent of the farmers indicated not being interested at all in microbiological mastitis diagnostics for CM. For SCM and DCT, 27 and 55%, respectively, were not interested in microbiological mastitis diagnostics. Regarding test characteristics that farmers considered important, reliability was most often indicated (44-51% of the farmers). Additionally, a preferred time-to-result of ≤8 h for CM and ≤20 to 24 h for SCM and DCT and ≤7% false test outcomes were indicated as desired characteristics of microbiological mastitis diagnostics. Overall, a need seems to exist for microbiological mastitis diagnostic tests among Dutch dairy farmers, specifically for CM, and resulting in a treatment advice. The availability of a reliable diagnostic test, with a suitable time-to-result, will likely increase the use of microbiological mastitis diagnostics and eventually optimize antibiotic usage.