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Background: Travellers' diarrhoea (TD) is the most common infectious disease among travellers. In the Netherlands, stand-by or prophylactic antibiotics are not routinely prescribed to travellers. This study prospectively assessed the incidence rate, risk factors, and treatment of TD among immunocompetent travellers., Methods: Persons who attended the travel clinic of the Public Health Service Amsterdam in 2006-2007 before short-term travel to tropical and subtropical countries were invited to answer a questionnaire regarding sociodemographics and travel purpose; they were also asked to keep a daily structured travel diary, recording their itinerary, symptoms, and self-medication or consultation with a doctor. Diarrhoea episodes containing blood or mucous were considered severe., Results: Of 1202 travellers, the median age was 38 years, and the median travel duration 3 weeks. Of all episodes, 96% were mild. The median duration of TD was 2 days and significantly shorter in subsequent episodes compared to first episodes (p < 0.0005). Of first episodes 38% started in the first travel week. The incidence rate (IR) for first episodes was 2.49 (95% confidence interval [CI], 2.30-2.70) per 100 travel days, with the highest IR among travellers to South-Central and West Asia. The IR for first and subsequent episodes was comparable. Risk factors for first episodes included female sex, a Western country of birth, and tourism as the purpose of travel. The lowest risk was in travellers to South America. An independent risk factor for subsequent episodes was female sex. In total, 5% of travellers used antibiotics; of those, 92% had mild diarrhoea, and 53% received antibiotics over the counter., Conclusions: TD is common among travellers, but the overall course is mild, not requiring treatment. The incidence rates for first and second episodes are comparable. Female sex is a risk factor for the first episode, as well as subsequent ones. Prescription antibiotics are not needed in short-term healthy travellers.

Background: Immunocompromised travelers to developing countries are thought to have symptomatic infectious diseases more often and longer than non-immunocompromised travelers. Evidence for this is lacking. This study evaluates whether immunocompromised short-term travelers are at increased risk of diseases., Methods: A prospective study was performed between October 2003 and May 2010 among adult travelers using immunosuppressive agents (ISA) and travelers with inflammatory bowel disease (IBD), with their non-immunocompromised travel companions serving as matched controls with comparable exposure to infection. Data on symptoms of infectious diseases were recorded by using a structured diary., Results: Among 75 ISA, the incidence of travel-related diarrhea was 0.76 per person-month, and the number of symptomatic days 1.32 per month. For their 75 controls, figures were 0.66 and 1.50, respectively (p > 0.05). Among 71 IBD, the incidence was 1.19, and the number of symptomatic days was 2.48. For their 71 controls, figures were 0.73 and 1.31, respectively (p > 0.05). These differences also existed before travel. ISA had significantly more and longer travel-related signs of skin infection and IBD suffered more and longer from vomiting. As for other symptoms, no significant travel-related differences were found. Only 21% of immunocompromised travelers suffering from diarrhea used their stand-by antibiotics., Conclusions: ISA and IBD did not have symptomatic infectious diseases more often or longer than non-immunocompromised travelers, except for signs of travel-related skin infection among ISA. Routine prescription of stand-by antibiotics for these immunocompromised travelers to areas with good health facilities is probably not more useful than for healthy travelers., (© 2011 International Society of Travel Medicine.)

To assess the incidence of and risk factors for clinical and subclinical dengue virus (DENV) infection, we prospectively studied 1,207 adult short-term travelers from the Netherlands to dengue-endemic areas. Participants donated blood samples for serologic testing before and after travel. Blood samples were tested for antibodies against DENV. Seroconversion occurred in 14 (1.2%) travelers at risk. The incidence rate was 14.6 per 1,000 person-months. The incidence rate was significantly higher for travel during the rainy months. Dengue-like illness occurred in 5 of the 14 travelers who seroconverted. Seroconversion was significantly related to fever, retro-orbital pain, myalgia, arthralgia, and skin rash. The risk for DENV infection for short-term travelers to dengue-endemic areas is substantial. The incidence rate for this study is comparable with that in 2 other serology-based prospective studies conducted in the 1990s.

Background: This study prospectively assessed the occurrence of clinical and subclinical schistosomiasis, strongyloidiasis, filariasis, and toxocariasis, and the screening value of eosinophilia in adult short-term travelers to helminth-endemic countries., Methods: Visitors of a pre-travel health advice centre donated blood samples for serology and blood cell count before and after travel. Samples were tested for eosinophilia, and for antibodies against schistosomiasis, strongyloidiasis, filariasis, and toxocariasis. Previous infection was defined as seropositivity in pre- and post-travel samples. Recent infection was defined as a seroconversion. Symptoms of parasitic disease were recorded in a structured diary., Results: Previous infection was found in 112 of 1207 subjects: schistosomiasis in 2.7%, strongyloidiasis in 2.4%, filariasis in 3.4%, and toxocariasis in 1.8%. Recent schistosomiasis was found in 0.51% of susceptible subjects at risk, strongyloidiasis in 0.25%, filariasis in 0.09%, and toxocariasis in 0.08%. The incidence rate per 1000 person-months was 6.4, 3.2, 1.1, and 1.1, respectively. Recent infections were largely contracted in Asia. The positive predictive value of eosinophilia for diagnosis was 15% for previous infection and 0% for recent infection. None of the symptoms studied had any positive predictive value., Conclusion: The chance of infection with schistosomiasis, strongyloidiasis, filariasis, and toxocariasis during one short-term journey to an endemic area is low. However, previous stay leads to a cumulative risk of infection. Testing for eosinophilia appeared to be of no value in routine screening of asymptomatic travelers for the four helminthic infections. Findings need to be replicated in larger prospective studies.

A turbidimetric method to determine serum C-reactive protein (CRP) concentration, based on soybean oil-phosphocholine interaction, was performed on horse serum samples to evaluate its potential diagnostic value in veterinary medicine. Intralipid 20% in 0.1 M Tris-calcium buffer (pH 7.5) was added to horse serum. After 30 min of incubation at 37 °C, the CRP-phosphocholine complexes were turbidimetrically, bichromatically (660 nm/700 nm) quantified on a commercial analyzer. Furthermore, comparison between CRP and other inflammatory markers, including white blood cell and neutrophil counts, was performed to evaluate the diagnostic value of both tests. Standardization of the assay was done using a commercial human CRP calibrator. The CRP measurements were performed on serum samples (296 patients and 34 controls). Reference values were found to be lower than 10 mg/l. The method was found to be linear between 1 and 400 mg/l. A moderate correlation was observed between CRP values and the relative neutrophil counts. Receiver-operating characteristics analysis demonstrated the area under the curve for CRP was 0.928, which was superior (P < 0.001) to the neutrophil count (0.804) and the leukocyte count (0.664) in detecting the presence of inflammation. This CRP assay showed reliable results as an acute phase test in horses, confirming its species-independent capability to detect CRP in various mammals, including horses.

Background: Travelers with diabetes mellitus to developing countries are thought to have symptomatic infectious diseases more often and longer than travelers without diabetes. Evidence for this is needed. This study evaluates whether travelers with diabetes are at increased risk of symptomatic infectious diseases., Methods: A prospective study was performed between October 2003 and February 2008 among adult medication-dependent travelers with diabetes, with their healthy travel companions without diabetes serving as matched controls. Thus, travelers with diabetes and controls were assumed to have comparable exposure to infection. Data on symptoms of infectious diseases were recorded by using a structured diary., Results: Among 70 travelers with insulin-dependent diabetes, the incidence of travel-related diarrhea was 0.99 per person-month, and the median number of symptomatic days 1.54 per month. For their 70 controls, figures were 0.74 and 1.57, respectively (p > 0.05). Among 82 travelers with non-insulin-dependent diabetes, incidence was 0.75, and the median number of symptomatic days was 1.68. For their 82 controls, figures were 0.70 and 1.68, respectively (p > 0.05). As for other symptoms, no significant travel-related differences were found. Only 17% of travelers with diabetes suffering from diarrhea used their stand-by antibiotics., Conclusions: Medication-dependent travelers with diabetes traveling to developing countries do not have symptomatic infectious diseases more often or longer than travelers without diabetes. Routine prescription of stand-by antibiotics for travelers with diabetes to areas with good health facilities is probably not more useful than for healthy travelers.

Background: C-reactive protein (CRP) is able to bind phospholipids (mainly phosphocholine) in the presence of calcium ions. We investigated the use of this property for developing an affordable turbidimetrical CRP assay based on diluted soy oil., Methods: Serum (or heparinized plasma) was mixed with Intralipid 20% in Tris-calcium buffer (pH 7.5). After 30 min of incubation at 37 degrees C, the CRP-phospholipids complexes were measured by turbidimetry (660 nm/700 nm) with a Cobas 6000 analyzer (Roche). Results were compared with those obtained using a typical immunoturbidimetric method (Roche)., Results: Good correlation (r(2)=0.931) was obtained between the functional and the immunoturbidimetric CRP assay. Within-run and between-run %CV values for the functional assay were 2.4% (100 mg/L); 6.0% (50 mg/L); 10% (20 mg/L), and 3.6% (100 mg/L); 8.0% (50 mg/L); 11% (20 mg/L), respectively. The limit of detection was 7 mg/L. Results were not affected by serum calcium, triglyceride, or phospholipid concentrations., Conclusions: The functional CRP assay allowed measurement of CRP in serum and plasma in the range of 7 mg/L-400 mg/L. The assay is particularly suited in conditions where resources are restricted. Since the assay is species independent, the described functional CRP assay could be used for veterinary purposes as well.

Objectives: To study groups of prostitutes and clients of prostitutes in order (i) to determine HIV prevalence and sexual risk behaviour, (ii) to determine differences between samples recruited within and outside a clinic for sexually transmitted diseases (STD) and (iii) to determine correlates of inconsistent condom use (ICU) among both groups., Design: Participants were interviewed and anonymously tested for HIV-antibody; approximately half were recruited at a clinic for sexually transmitted diseases (STD) and half at prostitute working places., Setting: An STD clinic and prostitute working places in Amsterdam in 1991., Subjects: 201 female prostitutes without a history of injecting drugs and 213 male clients of female prostitutes., Main Outcome Measures: antibodies to HIV, consistency of condom use in commercial vaginal contacts in the preceding 6 months., Results: HIV prevalence was low: three prostitutes (1.5%; 95% CI 0.5-4.6%) and one client (0.5%; 95% CI 0.1-3.3%) were infected. All three HIV positive prostitutes originated from AIDS-endemic countries, came to the Netherlands only recently and were recruited outside the STD clinic. Large differences between subgroups resulted from the two recruitment methods: while clients of prostitutes with relatively high risk behaviour were strongly represented among the STD clinic sample, high risk prostitutes were underrepresented in this sample. Consistent condom use (with 100% of contacts) was reported by 66% of prostitutes and 56% of clients of prostitutes. Inconsistent condom use was found to be high among prostitutes who had migrated from Latin America and among migrant clients of prostitutes., Conclusions: When monitoring HIV infection one must take into account imported cases. HIV prevention efforts should be particularly focused at prostitutes from Latin America and at clients of prostitutes who migrated to the Netherlands.

Based on a review of the literature the possible application of biochemical markers in the early detection of periodontal disease is discussed, using crevicular fluid.

Quality control of albumin solutions for human use is of utmost importance because the presence of impurities can provoke adverse reactions in treated patients. Three different techniques were used to detect the presence of albumin oligomers and polymers as well as foreign proteins in commercial solutions. The relative concentrations of the former two were estimated using size-exclusion high-performance liquid chromatography. Isoelectric focusing and two-dimensional immunoelectrophoresis allowed detection of other contaminants of proteinaceous nature. The application of this combination of techniques supersedes the traditional approaches (gel filtration on polydextran gels, electrophoresis) in specificity and speed. Analysis of 34 lots of commercial albumin solutions from 22 manufacturers revealed the superior quality of preparations of placental rather than plasmatic origin.

For this sensitive RIA for 1 alpha,25-dihydroxyvitamin D, we used antibodies to 1 alpha,25-dihydroxycholecalciferol-3-hemisuccinate conjugated to bovine serum albumin, raised in eggs by immunization of chickens. We describe an efficient method for purification of IgG from egg yolk. We characterized these antibodies with immunoelectrophoresis and by radioimmunoassay. These antibodies show a high affinity for 1 alpha,25-dihydroxyvitamin D3 but cross react with other vitamin D metabolites as well. Extraction and liquid chromatography are necessary to isolate the 1 alpha,25-dihydroxyvitamin D from human serum or plasma before determination by RIA. The sensitivity of the assay is estimated at 5 pg/tube.

Serum beta-galactosidase activity was found to be markedly increased in clotting blood from normal subjects, but patients with galactosialidosis showed only a slight increase of this enzyme activity. Consequently, the beta-galactosidase activity was low in serum after long-term clotting in patients with this disease. The mechanism of the enzyme activation is unknown. The use of anticoagulants completely inhibited the activation.

We studied the prevalence of Chlamydia trachomatis (CT) infection as well as its predictors among a sample (1000) of visitors (651 male, 349 female) of a clinic for sexually transmitted diseases (STD) in Amsterdam. The prevalence of CT was higher than that of gonorrhoea: among men, 14.3% and 11.5% and among women, 12.9% and 6.3% respectively. Independent predictors for CT infections were for men: number of leucocytes in discharge or urine, nature of urethral discharge, age and sex behavior, and in women: being warned as source or contact of a STD, age, nature of cervical discharge and bleeding from the cervical ostium after insertion of a swab. As many as 92% of the male and 81% of the female visitors of our STD clinic should be examined for CT if the presence of anyone or more of these predictors is taken as a criterion. Even then, 5% of the CT infections in women would still be missed. Based on our study results, material for the diagnosis of CT will from now on be collected routinely from all female patients of our STD clinic as well as from all males with urethritis. We advocate the expansion in the Netherlands of facilities for laboratory CT detection and its standard inclusion in STD examination.

Dog alpha-1-acid glycoprotein was purified to homogeneity from dog serum in a three-step procedure involving precipitation with sulphosalicylic acid, isoelectric focusing and size exclusion chromatography. The molecular heterogeneity in the peptide part and in the carbohydrate part of the molecule was investigated with analytical isoelectric focusing in a narrow pH range and crossed immunoaffinity electrophoresis with concanavalin A (con A) in the first-dimension gel. Up to seven molecular forms with different isoelectric points were found, whereas only a single con A-dependent molecular form was detected.

Three kittens in a litter of Persian cats showed, from the age of eight weeks, tremor, ataxia, dysmetria, progressive weakness and emaciation. Cytoplasmic vacuolation was observed in neurons, mesenchymal and epithelial cells of tissues taken post mortem. The alpha-mannosidase activity of brain tissue of one cat tested was 4.8 per cent of control values and the urine of two cats contained large amounts of mannose-rich oligosaccharides.

The leukocytes of male patients with Fabry's disease are deficient in alpha-galactosidase. The alpha-galactosidase activity in the leukocytes of female carriers of the disease is 15 to 40 percent of the amount present in normal leukocytes. The activities of beta-galactosidase, beta-acetylgalactosaminidase, and beta-acetylglucosaminidase in the leukocytes of affected individuals are normal.

Total activities of acid hydrolases in liver of two patients with mucopolysaccharidosis are decreased for beta-galactosidase, alpha-galactosidase, and arylsulfatase A; total activities of four other hydrolases are normal or increased. The isoenzyme distribution of five hydrolases (beta-glucuronidase, alpha-glucosidase, beta- galactosidase, N-acetyl-beta-glucosaminidase, and alpha-galactosidase) is ábnormal in that the isoelectric points (by isoelectric focusing) of these enzymes are more acid than in control liver. Along with the isoenzyme abnormalities different kinds of glycolipids were stored in kidney, liver, and brain. The isoenzyme abnormalities can be reproduced in vitro by addition of chondroitin sulfate to a homogenate of normal liver, suggesting that stable binding occurs between mucopolysaccharides and the hydrolase molecules. After the addition of chondroitin sulfate, the total activity of beta-galactosidase is inhibited, whereas other hydrolases are affected only slightly or not at all.