Q Fever among Culling Workers, the Netherlands, 2009–2010

In 2009, dairy goat farms in the Netherlands were implicated in >2,300 cases of Q fever; in response, 51,820 small ruminants were culled. Among 517 culling workers, despite use of personal protective equipment, 17.5% seroconverted for antibodies to Coxiella burnetii. Vaccination of culling workers could be considered

Measurement of antibodies to avian influenza virus A(H7N7) in humans by hemagglutination inhibition test.

During the epizootic of highly pathogenic avian influenza A(H7N7) in 2003 in The Netherlands, RT-PCR and culture confirmed infection was detected in 89 persons who were ill. A modified hemagglutination inhibition (HI) test using horse erythrocytes and 2 hemagglutinating units of virus was applied to assess retrospectively the extent of human (subclinical) infection. Validation of the HI-test with sera from 34 RT-PCR and culture confirmed A(H7) infected persons and sera from 100 persons from a human influenza vaccine trial in autumn 2002 showed that this HI-test had a sensitivity of 85% and a specificity of 100% when using a cut-off titer of > or =10. Using this cut-off value, A(H7) specific antibodies were detected in 49% of 508 persons exposed to poultry and in 64% of 63 persons exposed to A(H7) infected persons. Correlation of seropositivity with the occurrence of eye symptoms in exposed persons who had not received antiviral prophylaxis and of reduced seropositivity with taking antiviral prophylaxis provided further evidence that the A(H7) HI antibody titers were real. In conclusion, by applying an HI-test using horse erythrocytes human antibodies against the avian A(H7N7) virus were detected with high sensitivity and specificity in an unexpectedly high proportion of exposed persons

High probability of avian influenza virus (H7N7) transmission from poultry to humans active in disease control on infected farms

An epizootic of avian influenza (H7N7) caused a large number of human infections in The Netherlands in 2003. We used data from this epizootic to estimate infection probabilities for persons involved in disease control on infected farms. Analyses were based on databases containing information on the infected farms, person-visits to these farms, and exposure variables (number of birds present, housing type, poultry type, depopulation method, period during epizootic). Case definition was based on self-reported conjunctivitis and positive response to hemagglutination inhibition assay. A high infection probability was associated with clinical inspection of poultry in the area surrounding infected flocks (7.6%; 95% confidence interval [CI], 1.4%-18.9%) and active culling during depopulation (6.2%; 95% CI, 3.7%-9.6%). Low probabilities were estimated for management of biosecurity (0.0%; 95% CI, 0.0%-1.0%) and cleaning assistance during depopulation (0.0%; 95% CI, 0.0%-9.2%). No significant association was observed between the probability of infection and the exposure variables

Utility of the first few100 approach during the 2009 influenza A(H1N1) pandemic in the Netherlands

Abstract Background To guide policy and control measures, decent scientific data are needed for a comprehensive assessment of epidemiological, clinical and virological characteristics of the First Few hundred (FF100) cases. We discuss the feasibility of the FF100 approach during the 2009 pandemic and the added value compared with alternative data sources available. Methods The pandemic preparedness plan enabled us to perform a case–control study, assessing patient characteristics and risk factors for experiencing symptomatic influenza A(H1N1)2009 infection and providing insight into transmission. We assessed to what extent timely and novel data were generated compared to other available data sources. Results In May-December 2009, a total of 68 cases and 48 controls were included in the study. Underlying non-respiratory diseases were significantly more common among cases compared to controls, while a protective effect was found for frequent hand washing. Seroconversion was found for 7/30 controls (23%), and persisting high titers for 4/30 controls (13%). The labour-intensive study design resulted in slow and restricted recruitment. Conclusions The findings of our case–control study gave new insights in transmission risks and possible interventions for improved control. Nevertheless, the FF100 approach lacked timeliness and power due to limited recruitment. For future pandemics we suggest pooling data from several countries, to enable collecting sufficient data in a relatively short period.</p