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E Linder

Publications and source records attributed to E Linder.

At least 37 records · Page 2Linked to original sources
PubMed1997

Prevalence of intestinal parasites in the human population of León, Nicaragua.

Intestinal parasites appear to be prevalent in Nicaragua, which motivated a more extensive prevalence study in which socioeconomic conditions such as degree of crowding, quality of water supply, type of floor and disposal of excretion, were considered. The study was performed on 1267 stool samples from about 8% of the citizens of the city of León. The overall prevalence of intestinal pathogenic parasites among the 1267 individuals was found to be 47.2%. The prevalence of Entamoeba histolytica/dispar was 18.6% followed by Giardia (15.9%) and Ascaris (13.4%). Other helminths such as hookworms and Strongyloides sp. were found at very low rates. Giardia, in contrast to worm infections, was prevalent already in children under 5 years of age. E. histolytica/dispar increased with age and remained high. Of 595 individuals with intestinal parasites 81% were living in 'poor' conditions and in 13 clusters of households, a lower prevalence of parasites was seen in households characterised as having good socioeconomic conditions. However, several variables appear to be important in determining the prevalence of the individual intestinal protozoa and helminths encountered.

Animals↗
PubMed1996

Detection of Pneumocystis carinii DNA by filtration of air.

The high incidence of pneumonia caused by Pneumocystis carinii in immunosuppressed patients makes it the most important parasite in non-tropical geographical regions. It has recently been shown to be a fungus, but several aspects of this organism are still poorly understood. A major question of clinical relevance is the nature of transmission and, thereby, the related problem of prevention. The mode of P. carinii transmission is thought to be air, but this is based on circumstantial evidence, the transmissive stage has not been identified. We attempted to capture P. carinii by filtration of air in the vicinity of cages containing P. carinii infected Wistar rats. Using nested polymerase chain reaction amplification of the thymidylate synthase gene to demonstrate P. carinii we were able to demonstrate P. carinii DNA on such filters. This strongly supports the suggested mechanism of transmission of Pneumocystis by means of airborne spores and suggests an approach to their isolation and characterization.

Air Microbiology↗
PubMed1996

A rapid and simple nested PCR assay for the detection of Pneumocystis carinii in sputum samples.

Detection of Pneumocystis carinii by the polymerase chain reaction (PCR), based on the thymidylate synthase (TS) gene of rat P. carinii, is a specific and sensitive method for the detection of the parasite in respiratory samples. However, the use of the method is limited by a laborious phenol-chloroform DNA extraction method and an expensive and time-consuming hybridization procedure. For routine clinical samples, DNA preparation can be simplified and hybridization substituted by a nested PCR technique. Such a modified PCR procedure, based on the TS gene of P. carinii, was evaluated on 190 induced sputum samples from 50 immunosuppressed patients, infected with human immunodeficiency virus (HIV), with and without symptoms of P. carinii pneumonia (PCP). The PCR assay, preceded by a rapid DNA preparation (Wizard DNA Clean-up), detected P. carinii-DNA in 13/15 sputa containing parasites as seen by microscopy using immunocytochemical (IFL) staining, and in 10 additional sputum samples lacking demonstrable parasites by microscopy. These samples are to be considered as 'true' positives, since all but 2 were from patients, who developed a PCP within 1 year. We conclude that the nested PCR assay is more sensitive than IFL for the detection of P. carinii in AIDS patients, prior to the debut of PCP symptoms.

Animals↗
PubMed1996

Seroepidemiology of toxoplasmosis in humans: possible transmission routes in Costa Rica.

A serological survey with immunofluorescence techniques to detect toxoplasma antibodies was done on a sample of 1234 Costa Ricans. The overall prevalence was 76%; it increased from 60% in donors aged 1-4 years to 90% in those over 25 years. No significant difference was found in seropositivity between males (42.8%) and females (57.2%) and between donors from urban and rural (LPI) areas. Consumption of raw meat, especially prepared meat, was significantly correlated with antibody prevalence, but cat contact was not, indicating a possible change in the usual pattern of transmission described for the country. Nevertheless, our data suggest that infectious cat feces play an important role in the transmission of toxoplasmosis.

Adolescent↗
PubMed1995

Seroepidemiology of Toxoplasma gondii among pregnant women in different parts of Sweden.

Surveys of pregnant women in four areas of Sweden in 1987-88, reveal a significant trend for decrease in Toxoplasma seroprevalence from Gotland island (26%, n = 467) in the south through Orebro county (18%, n = 1413) and Stockholm area (18%, n = 939), to Northern Sweden (12%, n = 837). No within area differences were observed between samples from rural and urban localities. Quantitative antibody data indicate marginally higher levels in the north than in the south, and a significant declining trend by age only in Orebro county. Incidence models are used to describe age-seroprevalence profiles for each area, using different assumptions about age- and time-specific infection rates, and to estimate the risk of maternal infection at the time of the survey. It is shown that the patterns of seroprevalence with age in Orebro county and Northern Sweden, but not Gotland island or Stockholm, strongly implicate time-dependent changes in Toxoplasma incidence, consistent with a declining incidence in the past which has possibly been reversed in recent years. The estimates of Toxoplasma incidence and risk of maternal toxoplasmosis are strongly dependent upon the underlying assumption of temporal change in incidence, with wide ranges in the predicted values. These studies demonstrate the difficulties in interpretation of horizontal cross-sectional data and the need for longitudinal studies of age-prevalence and seroconversion in the determination of the true risk of maternal toxoplasmosis.

Adolescent↗
PubMed1995

Detection of Giardia lamblia cysts in stool samples by immunofluorescence using monoclonal antibody.

The diagnostic potential of indirect immunofluorescence to detect Giardia cysts in stool samples using a cyst-specific anti-Giardia lamblia monoclonal antibody was evaluated in comparison to conventional light microscopy. One hundred fifty specimens from clinically suspected Giardia infections and 50 control samples from microscopically proved Giardia infections were tested. Giardia cysts were found in 15 of 150 (10%) samples tested by light microscopy, whereas immunofluorescence microscopy detected 35 of 150 (23%) positive samples. Forty-six of the 50 reference samples previously shown to contain Giardia cysts were positive. Apparently, the four discrepant samples contained very low numbers of parasites, as none could be detected by conventional microscopy. The results show that Giardia lamblia cysts are detected significantly more frequently using the antibody marker. The doubled number of positive stool specimens and detection of as little as four cysts per sample suggest that microscopical examination of samples can be improved by immunofluorescent staining of Giardia lamblia cysts.

Animals↗
PubMed1994

Seroreactivity to Pneumocystis carinii in patients with AIDS versus other immunosuppressed patients.

The aim was to study the humoral response to Pneumocystis carinii and its diagnostic use in patients with P. carinii pneumonia (PCP). The antibody response was measured by indirect immunofluorescence in AIDS patients versus other immunosuppressed patients with 122 episodes of confirmed PCP. During the early acute stage of the pneumonia, anti-P. carinii antibodies were found in 17% of AIDS and 24% of other immunosuppressed patients. In the second serum sample, antibodies were still found in 17% of the AIDS patients but in as many as 56% of the otherwise immunosuppressed patients. Antibodies were also found in 17% of HIV-positive and 15% of other immunosuppressed control patients, but only in 3% of immunocompetent controls (p < 0.001). Paired sera were available from 55 patients during 58 PCP episodes. Seroconversion or a fourfold rise in titre was detected in only 1/36 (3%) AIDS patients but in 10/22 (45%), (95% c.i.: 24-66%) other immunosuppressed patients (p < 0.001). We conclude that AIDS patients seem to have lost their ability to develop a humoral response to P. carinii during pneumonia, whereas many other immunosuppressed patients do respond. In these patients the serological test against P. carinii was of no diagnostic value in the acute phase of the infection, whereas when analysing paired sera it was a useful complement to the clinical diagnosis.

AIDS-Related Opportunistic Infections↗
PubMed1994

Natural history of asymptomatic and symptomatic pneumocystis carinii infection in HIV infected patients.

The natural appearance of Pneumocystis carinii in induced sputum samples was studied in 60 HIV-infected patients with severe immunodeficiency and without a history of P. carinii pneumonia (PCP). The patients were prospectively evaluated for occurrence of P. carinii in induced sputum samples, PCP diagnosis and CD4+ cell counts during observation periods of 2 to 31 months. P. carinii was detected in 16 patients all of whom developed clinical PCP. In 5 patients P. carinii was detected 3 weeks to 8 months prior to clinical symptoms. Immunofluorescence using monoclonal antibody 3F6 was more sensitive than toluidine in detecting P. carinii in sputum samples (p < 0.05). In the patients who developed PCP a drop of the mean CD4 count to 40-50 x 10(6)/l was observed 200 days before diagnosis. However, out of 13 patients with CD4 counts of 0-20 x 10(6)/l only 7 developed PCP during 200 days of observation. The results do not support the suggested reactivation of a latent infection present in the vast majority of adults. PCP may instead result from exposure to the organism or presence of an unknown cofactor. We conclude that P. carinii is present in some asymptomatic HIV patients and that the detection of the organism in sputum should be regarded as pathological and prophylaxis or treatment inserted. The risk of transmission of P. carinii to patients with severe immunodeficiency should be seriously considered.

Adult↗
PubMed1994

Ultrastructural localization of monoclonal antibodies against Pneumocystis carinii. Differentiation between developmental stage and host origin.

The ultrastructural immunolocalization of target antigens recognized by two monoclonal antibodies against Pneumocystis carinii was investigated using both human- and rat-derived organism. Labelling was seen using both cryo electron microscopy and postembedding in Epon after fixation in glutaraldehyde. The antibodies showed different host species- and developmental stage specificity. One of the antibodies reacted with the outer membrane of all developmental stages of human-derived but not rat-derived organisms, whereas the other reacted only with the cyst form. The distribution of the latter was similar to that reported for methenamine silver, a widely used cytochemical stain for the parasite, and reacted with both human- and rat-derived organisms. The antibodies described appear to be useful markers in studies on the differentiation of Pneumocystis carinii.

Animals↗