Dataset Information

Asymptomatic renal colonization of humans in the peruvian Amazon by Leptospira.

ABSTRACT: Renal carriage and shedding of leptospires is characteristic of carrier or maintenance animal hosts. Sporadic reports indicate that after infection, humans may excrete leptospires for extended periods. We hypothesized that, like mammalian reservoir hosts, humans develop asymptomatic leptospiruria in settings of high disease transmission such as the Peruvian Amazon.Using a cross-sectional study design, we used a combination of epidemiological data, serology and molecular detection of the leptospiral 16S rRNA gene to identify asymptomatic urinary shedders of Leptospira. Approximately one-third of the 314 asymptomatic participants had circulating anti-leptospiral antibodies. Among enrolled participants, 189/314 (59%) had evidence of recent infection (microscopic agglutination test (MAT0 >or=1:800 or ELISA IgM-positive or both). The proportion of MAT-positive and high MAT-titer (>or=1:800) persons was higher in men than women (p = 0.006). Among these people, 13/314 (4.1%) had Leptospira DNA-positive urine samples. Of these, the 16S rRNA gene from 10 samples was able to be sequenced. The urine-derived species clustered within both pathogenic (n = 6) and intermediate clades of Leptospira (n = 4). All of the thirteen participants with leptospiral DNA in urine were women. The median age of the DNA-positive group was older compared to the negative group (p

SUBMITTER: Ganoza CA

PROVIDER: S-EPMC2826405 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature

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Asymptomatic renal colonization of humans in the peruvian Amazon by Leptospira.

Ganoza Christian A CA Matthias Michael A MA Saito Mayuko M Cespedes Manuel M Gotuzzo Eduardo E Vinetz Joseph M JM

PLoS neglected tropical diseases 20100223 2

<h4>Background</h4>Renal carriage and shedding of leptospires is characteristic of carrier or maintenance animal hosts. Sporadic reports indicate that after infection, humans may excrete leptospires for extended periods. We hypothesized that, like mammalian reservoir hosts, humans develop asymptomatic leptospiruria in settings of high disease transmission such as the Peruvian Amazon.<h4>Methodology/principal findings</h4>Using a cross-sectional study design, we used a combination of epidemiologi ...[more]

PMID: 20186328

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Project description:IntroductionHerein, we tested the hypothesis that Asymptomatic P. vivax (Pv) infected individuals (Asym) feature different epidemiological, clinical and biochemical characteristics, as well as hematological parameters, potentially predictive of clinical immunity in comparison to symptomatic Pv infected individuals (Sym).MethodologyBetween 2018 - 2021, we conducted 11 population screenings (PS, Day 0 (D0)) in 13 different riverine communities around Iquitos city, in the Peruvian Amazon, to identify Pv Sym and Asym individuals. A group of these individuals agreed to participate in a nested case - control study to evaluate biochemical and hematological parameters. Pv Asym individuals did not present common malaria symptoms (fever, headache, and chills), had a positive/negative microscopy result, a positive qPCR result, reported no history of antimalarial treatment during the last month, and were followed-up weekly until Day 21 (D21). Control individuals, had a negative malaria microscopy and qPCR result, no history of antimalarial treatment or malaria infections during the last three years, and no history of comorbidities or chronic infections.ResultsFrom the 2159 individuals screened during PS, data revealed a low but heterogeneous Pv prevalence across the communities (11.4%), where most infections were Asym (66.7%) and submicroscopic (82.9%). A total of 29 Asym, 49 Sym, and 30 control individuals participated in the nested case - control study (n=78). Ten of the individuals that were initially Asym at D0, experienced malaria symptoms during follow up and therefore, were included in the Sym group. 29 individuals remained Asym throughout all follow-ups. High levels of eosinophils were found in Asym individuals in comparison to Sym and controls.ConclusionFor the first-time, key epidemiological, hematological, and biochemical features are reported from Pv Asym infections from the Peruvian Amazon. These results should be considered for the design and reshaping of malaria control measures as the country moves toward malaria elimination.

Project description:Malaria transmission requires that Anopheles mosquitoes ingest Plasmodium gametocyte stages circulating in the human bloodstream. In the context of malaria elimination, understanding the epidemiology of gametocytes relative to all Plasmodium infections and the contribution of asymptomatic and sub-microscopic parasite carriers to the gametocyte reservoir is necessary, especially in low endemic settings with predominance of P.vivax. A 13-month longitudinal study was conducted in two communities (n = 1935 individuals) of Loreto Department, Peru, with five active screenings for Plasmodium infections and gametocyte stages by quantitative real-time PCR (qPCR) and reverse transcription (RT)-qPCR, respectively. Parasite prevalence by qPCR was 7.2% for P.vivax (n = 520/7235; range by survey 6.0%-8.1%) and 3.2% for P.falciparum (n = 235/7235; range by survey 0.4%-7.7%). Sub-microscopic infections accounted for 73.5% of P.vivax (range by survey 60%-89%) and almost the totality of P.falciparum cases. Gametocytes were found in 28.4% P.vivax infections (range by survey 18.7%-34.1%), with a peak of 61.5% in one community at the start of the transmission season. About 59.8% of all P.vivax gametocyte carriers were asymptomatic and 31.9% were sub-microscopic. Age patterns for gametocyte prevalence paralleled asexual stage infections and peaked among >15-25 year old individuals. Asexual parasite density was found to be the strongest predictor for P.vivax gametocyte presence in longitudinal multivariate analysis (odds ratio 2.33 [95% confidence interval 1.96, 2.78]; P<0.001). Despite significant differences in seasonality patterns and P.vivax prevalence found at the local scale, sub-microscopic and asymptomatic infections predominate and contribute significantly to the gametocyte reservoir in different communities of the Peruvian Amazon. Control and elimination campaigns need sensitive tools to detect all infections that escape routine malaria surveillance, which may contribute to maintain transmission in the region.

Dataset Information

Asymptomatic renal colonization of humans in the peruvian Amazon by Leptospira.

Publications

Asymptomatic renal colonization of humans in the peruvian Amazon by Leptospira.

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