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Biomedical subjects

L G Visser

Publications and source records attributed to L G Visser.

At least 19 recordsLinked to original sources
PubMed2006

[The risk of yellow fever in travellers].

Yellow fever is a tropical virus disease characterised by high fever, jaundice, heart and kidney failure, and haemorrhagic diathesis. The causative Flavivirus is endemic in parts of tropical Africa and South America and is transmitted among humans and primates by mosquitoes. The chance that an unvaccinated traveller to West Africa will die of yellow fever is estimated at 1:650 to 1:5000 visitors per month of stay, depending on whether an epidemic occurs. Vaccination with the attenuated yellow fever Asibi 17D virus results in limited virus replication in the body and long-term protection due to the formation of neutralising antibodies. Vaccination is contraindicated in immunocompromised persons. Serious disseminated disease and encephalitis due to infection with the vaccine virus strain are seen more often in the elderly. One should therefore refrain from vaccination in persons over 60 years of age when the risk of infection is negligible. In recent years, the number of yellow fever epidemics has risen substantially, particularly in West Africa and the Amazon region. Reintroduction of yellow fever vaccination in childhood vaccination programmes is necessary in endemic areas to turn the tide of increasing outbreaks of yellow fever.

Animals↗
PubMed2006

Helicobacter pylori infection and typhoid fever in Jakarta, Indonesia.

We evaluated the association between typhoid fever and Helicobacter pylori infection, as the latter microorganism may influence gastric acid secretion and consequently increase susceptibility to Salmonella typhi infection. Anti-H. pylori IgG and IgA antibody titres (ELISA) and gastrin concentration (RIA) were determined in the plasma of 87 blood culture-confirmed typhoid fever cases (collected after clinical recovery) and 232 random healthy controls without a history of typhoid fever, in the Jatinegara district, Jakarta. Patients with typhoid fever more often than controls were seropositive for H. pylori IgG (67% vs. 50%, P<0.008), when antibody titres were dichotomized around median titres observed in controls. H. pylori IgA seropositivity was not associated with typhoid fever. Plasma gastrin concentrations indicative of hypochlorhydria (i.e. gastrin > or =25 or > or =100 ng/l) were not significantly elevated in typhoid fever cases compared to controls (P=0.54 and P=0.27 respectively). In a multivariate analysis, typhoid fever was independently associated with young age (<33 years, median age of the controls) [odds ratio (OR) 7.93, 95% confidence interval (CI) 3.90-16.10], and H. pylori IgG seropositivity (OR 1.93, 95% CI 1.10-3.40). Typhoid fever was independently associated with H. pylori IgG seropositivity, but not with elevated gastrin concentration. Therefore, the association suggests a common risk of environmental exposure to both bacteria, e.g. poor hygiene, rather than a causal relationship via reduced gastric acid production.

Adolescent↗
PubMed2005

Analysis of efficacy of CVD 103-HgR live oral cholera vaccine against all-cause travellers' diarrhoea in a randomised, double-blind, placebo-controlled study.

Enterotoxigenic Escherichia coli (ETEC), which produces heat labile toxin (LT) and/or heat stable toxin (ST), is considered to be the most common known cause of travellers' diarrhoea (TD). Owing to the antigenic similarity between cholera toxin and LT, immunization with inactivated oral B-subunit/whole-cell cholera vaccine (BS-WC) offers short term (3 months) but significant (>67%) protection against TD caused by LT-related ETEC. Since it expresses the cholera toxin B (CTB) subunit, the live attenuated oral cholera vaccine strain CVD 103-HgR, may induce similar protection. A trial was performed to determine if CVD 103-HgR live oral cholera vaccine would provide a protective efficacy of at least 50% against TD. In addition, the protective efficacy of the vaccine against TD specifically due to LT-ETEC and LT/ST-ETEC was determined. Volunteers (n=134) travelling to Indonesia, India, Thailand or West-Africa were randomised to receive either a placebo (n=65) or the vaccine (n=69). In the placebo group, 46% reported an episode of diarrhoea, compared to 52% in the vaccine group. No significant group differences were found with regard to incidence, duration or severity of all caused TD or ETEC-associated TD. However, ETEC-associated TD occurred earlier in the placebo group (median 5 days), compared to the vaccine group (median 15 days). In conclusion, CVD 103-HgR live oral cholera vaccine failed to provide a 50% protection against TD. This study does not exclude that the vaccine may offer a short-lived protection against ETEC-associated TD. However, the power of the study was limited by the unexpected low incidence of LT-ETEC-associated diarrhoea (9% of all TD) compared to ST-associated TD (24% of all TD).

Administration, Oral↗
PubMed2004

[Outbreak of amoebiasis in a Dutch family; tropics unexpectedly nearby].

An amoebic liver abscess, amoebic dysentery and asymptomatic cyst passage were diagnosed in a father, a mother and one of their three children, respectively. One of the other children had been in the tropics, but only after the father's symptoms had begun. All three family members were infected with the same strain of Entamoeba histolytica as determined by polymerase chain reaction (PCR)-based DNA typing. The source of infection was most probably in Southern Italy where the family regularly spent their summer holidays. All three infected patients recovered after drug treatment. In a patient with a liver abscess or colitis, amoebiasis should be considered even in the absence of a history of a stay in the tropics. Stool samples should be examined for amoebic cysts and trophozoites. PCR analysis of parasite DNA extracted directly from stool samples makes differentiation between the morphologically identical cysts of E. histolytica and the non-pathogenic Entamoeba dispar possible. In addition, serum antibodies to E. histolytica are almost always present in symptomatic patients. Invasive infections with E. histolytica require treatment with a tissue amoebicidal drug, followed by a contact amoebicide to prevent recurrence. Currently, paromomycin is considered to be the first-line luminal amoebicide because of its efficacy and safety.

Adolescent↗
PubMed2004

Risk factors for transmission of foodborne illness in restaurants and street vendors in Jakarta, Indonesia.

In a previous risk factor study in Jakarta we identified purchasing street food as an independent risk factor for paratyphoid. Eating from restaurants, however, was not associated with disease. To explain these findings we compared 128 street food-vendors with 74 food handlers from restaurants in a cross-sectional study in the same study area. Poor hand-washing hygiene and direct hand contact with foods, male sex and low educational level were independent characteristics of street vendors in a logistic regression analysis. Faecal contamination of drinking water (in 65 % of samples), dishwater (in 91 %) and ice cubes (in 100 %) was frequent. Directly transmittable pathogens including S. typhi (n = 1) and non-typhoidal Salmonella spp. (n = 6) were isolated in faecal samples in 13 (7 %) vendors; the groups did not differ, however, in contamination rates of drinking water and Salmonella isolation rates in stools. Poor hygiene of street vendors compared to restaurant vendors, in combination with faecal carriage of enteric pathogens including S. typhi, may help explain the association found between purchasing street food and foodborne illness, in particular Salmonella infections. Public health interventions to reduce transmission of foodborne illness should focus on general hygienic measures in street food trade, i.e. hand washing with soap, adequate food-handling hygiene, and frequent renewal of dishwater.

Adult↗
PubMed2003

[Migrating subcutaneous swellings due to dirofilariasis after a visit to the South of France].

In two women, aged 59 and 31 years, who suffered from an itching cutaneous nodule, subcutaneous dirofilariasis was diagnosed. The disease is characterised by recurrent migrating subcutaneous nodules and swellings. Both patients recently visited the South of France. Laboratory examination revealed a moderate eosinophilia. In both patients, filaria antibodies were demonstrated during the course of the disease and a nodule was eventually resected. Parasitological examination revealed Dirofilaria repens. After this the swellings did not recur. Dirofilariasis is a zoonosis common in dogs and cats, and is transmitted by mosquitoes. In humans, the most common clinical manifestation is a migrating subcutaneous nodule in the case of D. repens, and a pulmonary infiltrate (coin lesion on radiographs) in the case of Dirofilaria immitis. Filarial serology is often positive. The diagnosis is confirmed by parasitological examination of the excised nodule. Dirofilariasis is usually innocuous; it disappears after the worm has died but can cause patients to worry.

Adult↗
PubMed2003

[A case of diphtheria in the Netherlands due to an infection with Corynebacterium ulcerans].

A 58-year-old woman was admitted due to a pseudomembranous pharyngitis. The patient had not been vaccinated against diphtheria. Corynebacterium ulcerans was cultured from a throat swab. The production of diphtheria toxin by these bacteria was demonstrated with PCR and an immunoprecipitation test. The patient was cared for in respiratory isolation and was treated with benzylpenicillin. She quickly recovered and was discharged four days after admission. A contact investigation did not reveal any dissemination of the toxin-producing C. ulcerans and a source was not found. In spite of the large-scale vaccination against diphtheria which has taken place in the Netherlands since 1953, a physician has to consider diphtheria in the differential diagnosis of patients who present with a clinical syndrome compatible with this disease. Either Corynebacterium diphtheriae or C. ulcerans could be the pathogen responsible.

Corynebacterium↗
PubMed2003

[Arthralgia and rash from Australia caused by Ross river virus].

A 58-year-old entomologist presented with disabling arthralgia after a recent visit to the Northern Territory of Australia. A faint maculopapular rash was noticed on the trunk and limbs. The presumptive diagnosis of RRV disease was confirmed by the finding of IgM and IgG antibodies against RRV in serum. RRV, a mosquito-transmitted alpha virus, is the most common cause of arboviral disease in Australia. This disease, initially referred to as epidemic polyarthritis, is characterised by joint pain, rash and constitutional manifestations. The reservoir of RRV are marsupials, other mammals and birds, but mosquitoes may also transmit the disease between humans. The diagnosis is mainly based on RRV-specific serology. In case of arthritis viral RNA sometimes can be detected in synovium biopsies by PCR. No specific therapy is available; the prognosis is favourable. Prevention is based on protection against mosquito bites by wearing clothes to protect the skin, and by using insect repellents.

Alphavirus Infections↗
PubMed2003

Clinical pharmacokinetics of cefamandole and ceftazidime administered by continuous intravenous infusion.

In view of the results of animal studies as well as theoretical considerations, continuous administration of beta-lactam antibiotics should be superior to intermittent administration because of the close relationship between efficacy and the duration of time in which the concentration of unbound antibiotics in plasma remains above the MIC. The aim of the present study was to establish the pharmacokinetic parameters of cefamandole and ceftazidime for patients receiving these cephalosporins by continuous infusion. The interindividual differences in the concentrations in plasma at the steady state were mainly attributable to variations in renal function, as estimated by the rate of creatinine clearance. Using these results, we derived formulas for both cephalosporins that can be used to determine on an individual basis the total daily dose needed to obtain a therapeutic concentration in plasma. These formulas were tested with a group of subsequent patients and proved to be practical and fairly reliable. For some patients, a correction for a possible underestimation of the renal clearance at presentation might be required.

Adult↗
PubMed2003

The contribution made by Schistosoma infection to non-traumatic disorders of the spinal cord in Malawi.

In Malawi, although schistosomal myelopathy has been reported in visitors from overseas who have swum in Lake Malawi, the incidence of this disorder in local residents has never been investigated. Consecutive patients with non-traumatic disorders of the spinal cord were therefore recruited in a hospital and a rehabilitation centre in Blantyre. Of the 33 patients investigated, 16 were presumed to be cases of schistosomal myelopathy as they had the markers of past or current schistosomiasis and apparently no other conditions that could explain their clinical features. There was microscopical and/or immunodiagnostic evidence indicating that eight of these presumptive cases had active schistosomiasis. All 16 presumptive cases had symptoms that were similar to those of 177 presumptive or proven cases of neuroschistosomiasis described in the scientific literature. Following antihelminthic treatment, eight of the presumptive cases showed marked improvement. Schistosomal myelopathy seems to occur relatively frequently in Malawi. Early treatment with praziquantel is strongly recommended for all patients with unexplained myelopathy and a history of exposure to schistosome cercariae.

Adolescent↗
PubMed2002

[How to treat a patient with indications for an infectious viral hemorrhagic fever].

Lassa, Ebola, Marburg and Crimean-Congo haemorrhagic fever viruses are the most important causes of viral haemorrhagic fever which is transmitted from person to person through contact with blood or excreta. A non-specific fever may be the initial symptom of viral haemorrhagic fever. By means of carefully noting where the patient has travelled, possible exposure to ill persons, vectors or an animal reservoir, and the incubation period (< or = 21 days versus longer), it is possible to estimate the risk of infection with one of these viruses. Using this approach it is possible to diagnose high-risk patients in good time and to take appropriate measures.

Adult↗