Travellers' risk behaviors and health problems: Post-travel follow up in two travel medicine centers in Italy.

OBJECTIVES: We examined the association between travellers' characteristics, compliance with pre-travel recommendations and health problems. METHODS: Volunteer travellers were enrolled and data collected using a questionnaire between 30-60 days after returning home. We analyzed the associations through bivariate and multivariate models. RESULTS: Of the 468 enrolled travelers, 68% consumed raw food and 81% food containing milk and/or eggs. 32% consumed street vendor food and 30% drinks containing ice. 24% used the recommended mechanical prophylaxis measures. 46% got sick during and/or after travel (gastrointestinal symptoms most frequently). Factors predisposing to health problems were female gender, youth/middle age, intermediate travel duration and profession. The American continent and staying in hostels and tents were significantly associated with febrile illness. Street vendor food was significantly associated with skin reactions. CONCLUSIONS: Adherence to behavioral recommendations remains low. Travellers must be informed of health risks during and after travel.

May car washing represent a risk for Legionella infection?

BACKGROUND: Legionella is a ubiquitous Gram-negative bacterium naturally found in aquatic environments. It can pose a health problem when it grows and spreads in man-made water systems. Legionella pneumophila is the most common cause of Legionnaires' disease nowadays, a community-acquired pneumonia with pulmonary symptoms and chest radiography no different from any other form of infectious pneumonia. Legionella monitoring is important for public health reasons, including the identification of unusual environmental sources of Legionella. METHODS: We report two cases of Legionnaires' disease associated with two different car wash installations in the province of Vicenza, in the Veneto region, northeastern Italy. Patients were not employees of the car wash installations, but users of the service. In both cases, Legionella antigen was detected in urine using the Alere BinaxNOW® Legionella Urinary Antigen, and Legionella antibodies were detected in serum using SERION ELISA classic Legionella pneumophila 1-7 IgG and IgM. Water samples were also analyzed as part of the surveillance program for Legionella prevention and control in compliance with the Italian guidelines. RESULTS: Both patients had clinical symptoms and chest radiography compatible with pneumonia, and only one of them had diabetes as a risk factor. Legionella urinary antigen and serological test on serum samples were positive for Legionella in both patients, even if much slighter in the case A due to the retrospective serological investigation performed a year later the episode and after the second clinical case occurred in the same district. The environmental investigations highlighted two different car wash plants as potential source of infection. A certified company using shock hyperchlorination was asked to disinfect the two plants and, subsequently, control samples resulted negative for Legionella pneumophila. CONCLUSION: Any water source producing aerosols should be considered at risk for the transmission of Legionella bacteria, including car wash installations frequently used by a large number of customers and where poor maintenance probably creates favorable conditions for Legionella overgrowth and spreading. Additional research is needed to ascertain optimal strategies for Legionella monitoring and control, but environmental surveillance, paying careful attention to possible unconventional sources, should remain an important component of any Legionnaires' disease prevention program. Additionally, all available diagnostic methods would be recommended for the confirmation of all cases even in the event of non-serogroup 1 Legionella pneumophila infection, probably underestimated at this time.

In vivo knee joint loading and kinematics before and after ACL transection in an animal model.

Osteoarthritis (OA) is typically diagnosed in humans in its final stage when joint movement becomes painful. Clinical information about the onset and the mechanisms triggering the degenerative responses are virtually non-existent. However, research on animal models of experimental OA shows that joint adaptations associated with the onset of OA can be detected as early as two to four weeks following disruption of the normal joint mechanics. Transection of the anterior cruciate ligament (ACL) has been shown to cause OA-like symptoms in various animal models including the cat. However. the changes in joint loading responsible for the early tissue responses have not been quantified in vivo. Consequently, the relationship between abnormal joint loading and the onset of OA remains unknown. The purpose of this study was to quantify knee loading before and early after ACL transection in the cat. Knee mechanics were assessed by measuring patellar tendon forces, gastrocnemius forces, knee flexor and extensor EMGs, and hindlimb kinematics before and 5, 7, and 9 days following ACL transection in six experimental and two sham-operated animals. The knee mechanics were not affected by sham-surgery but the muscular forces. knee extensor EMGs, and knee range of motion were reduced following ACL transection compared to corresponding pre-intervention values. These results suggest that ACL transection causes a general unloading and changed kinematics of the knee. We speculate that the decrease in loading and the altered kinematics are responsible for the onset of biologic adaptations of the knee. Precise data about the local joint contact mechanics before and after ACL transection are now required to further relate the detailed changes in the knee mechanics to the early joint changes.

All-optical switching and pulse routing in a distributed-feedback waveguide device.

Results of all-optical switching and pulse-routing experiments with a distributed-feedback multiple-quantum-well (MQW) nonlinear waveguide, operating at 1.55microm , are reported. The MQW material has been engineered, through the controlled introduction of defects, to lower the carrier lifetime from 2.5 ns to 280 ps. The energy required for switching is of the order of 1 pJ or less, the switching time is ~600 ps , and the on-off contrast exceeds 17 dB.

All-optical switching in distributed-feedback muiltiple-quantum-well waveguides.

We discuss experimental results that demonstrate all-optical switching and pulse-routing functionality, at 1.55 um, of nonlinear multiple-quantum-well waveguides equipped with a Bragg grating. Basing on the nonlinear Time-Domain Beam Propagation Method, the switching behavior has been theoretically investigated using a model, developed as part of this work.

A system for studying the mechanical properties of muscles and the sensorimotor control of muscle forces during unrestrained locomotion in the cat.

The purpose of this technical note is to describe an experimental approach that allows the study of mechanical properties of muscles in vivo during normal, unrestrained movements in an animal preparation, and that further allows the investigation of sensorimotor control of joint movements. The preparation contains direct muscle force and EMG measurements of the target muscles (as described previously), and a chronically implanted nerve cuff electrode that may be triggered manually or automatically based on the force output of the targeted muscle. The system has been tested successfully on ankle flexor and extensor muscles of five cats.

Telemetry system to record force and EMG from cat ankle extensor and tibialis anterior muscles.

The purpose of this technical note is to present the design of an eight-channel telemetry system of dimensions and weight small enough to record muscular forces and EMGs simultaneously from gastrocnemius, soleus, plantaris and tibialis anterior muscles of a freely moving cat. All schematics for constructing the telemetry device are shown in detail. Using this system, we were successful in measuring force and EMG data of all four instrumented muscles in freely moving animals. The telemetry system presented here has the advantage over a conventional cable system that recordings may be obtained at any time in the freely moving animal without interference by an experimenter.