Article

Leishmania panamensis transmission in the domestic environment: the results of a prospective epidemiological survey in Santander, Colombia.

Departamento de Ciencias Básicas, Facultad de Salud, Universidad Industrial de Santander, Bucaramanga, Santander, Colombia.
Biomédica: revista del Instituto Nacional de Salud (Impact Factor: 0.32). 11/2006; 26 Suppl 1:131-44.
Source: PubMed

ABSTRACT Domestic transmission now appears to be the principal route of Leishmania panamensis infection in deforested regions characterized by the replacement of primary forest by permanent plantations, i,e coffee or cacao crops. This paper presents the results of the disease patterns in a representative population of the Opón focus, in Santander, Colombia.
The principal aims were: 1) to measure the incidence rate in a representative population of the Opón focus; 2) to identify demographic risk factors for infection; 3) to estimate the proportion of infections which cause disease; 4) to estimate the protection against disease from acquired immunity; 5) to estimate the frequency of reactivations, and 6) to estimate the risk of mucosal leishmaniasis.
A 19 month prospective survey of leishmaniasis caused by Leishmania panamensis was carried out amongst 1380 people in a cacao growing region of Santander Department, Colombia. The population was diagnosed clinically and by the Montenegro skin test (at two time points).
The incidence rate was 0.19 infections/person-year, with 31% of infections apparently subclinical. The risk of acquiring cutaneous leishmaniasis decreased with age even in the absence of apparent previous infections. Protective immunity followed both clinical and subclinical infections, persisting for at least 10 years after a primary lesion. Mucocutaneous leishmaniasis was detected in 12% of the population with cutaneous lesions, of which 77% had mild symptoms, and 23% perforated nasal septa. The risk of mucosal leishmaniasis was greatest for males, and for people whose primary cutaneous lesion was on the head.
The average age of infection in Opón, 7.7 years (1/lambda), and the absence of gender as a risk factor is highly indicative of intradomiciliary or peridomiciliary transmission.

0 Bookmarks
 · 
52 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: T cell differentiation determines susceptibility and resistance to experimental cutaneous leishmaniasis, yet mixed T1/Th2 responses characterize the clinical spectrum of human infection with Leishmania (Viannia) species. To discern the interrelationship of T cell differentiation and outcome of human infection, we examined factors that regulate T cell differentiation and Th1/Th2 cytokine responses in asymptomatic infection, active and historical chronic and recurrent cutaneous leishmaniasis. T-bet, GATA-3, Foxp3, and cytokine gene expression were quantified by real-time polymerase chain reaction and correlated with interleukin 2, interferon gamma, tumor necrosis factor alpha, interleukin 4, interleukin 13, and interleukin 10 secretion during in vitro response to live Leishmania panamensis. Higher GATA-3 expression than T-bet expression occurred throughout the 15 days of coculture with promastigotes; however, neither transcription nor secretion of interleukin 4 was detected. A sustained inverse correlation between GATA-3 expression and secretion of proinflammatory cytokines interferon gamma and tumor necrosis factor alpha was observed in asymptomatic infection. In contrast, higher T-bet expression and a higher ratio of T-bet to GATA-3 characterized active recurrent disease. Down-regulation of T-bet and GATA-3 expression and increased interleukin 2 secretion, compared with control subjects, was directly correlated with Foxp3 expression and interleukin 13 secretion in chronic disease. Regulation of the inflammatory response rather than biased Th1/Th2 response distinguished asymptomatic and recalcitrant outcomes of infection with Leishmnania viannia species.
    The Journal of Infectious Diseases 08/2010; 202(3):406-15. · 5.85 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Measuring the impact of the Basic Colombian Health Plan for Preventing Cutaneous Leishmaniasis in three towns in the Santander department. An ecologic design using housing as the analysis unit. Children aged less than ten were randomly selected from rural schools and visited in their homes by trained volunteers. Structured survey-forms were filled in and every child was examined for scars or active cutaneous leishmaniasis lesions. Cluster-adjusted binomial regression was used when analysing data. Eighteen villages, 284 houses and 609 children aged less than 10 were surveyed. Scar/lesion prevalence was 19.1%, differences being noted between municipalities: El Playón 7.1%, Landázuri 32.8% and Rionegro 13.9%. Information regarding leishmaniasis had been received by 42.8% of the houses and 39.9% had received some type of intervention from the Basic Colombian Health Plan, bed-nets being the most frequent (92.5%). Basic Health Plan intervention showed a preventative effect in bivariate analysis; however, such effect was not evident following adjustment for other socioeconomic and environmental variables (PR = 1.39 IC 95% 0.76-2.56). Basic health plan intervention for cutaneous leishmaniasis prevention has had no significant association with scar/lesion prevalence in children aged less than ten in these rural areas, probably because its effect has been exceeded by local socioeconomic and environmental conditions, as well as administrative conditions related to the programmes' poor coverage.
    Revista de salud publica (Bogota, Colombia) 06/2006; 8 Suppl 1:116-28.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Infectious disease incidence is often male-biased. Two main hypotheses have been proposed to explain this observation. The physiological hypothesis (PH) emphasizes differences in sex hormones and genetic architecture, while the behavioral hypothesis (BH) stresses gender-related differences in exposure. Surprisingly, the population-level predictions of these hypotheses are yet to be thoroughly tested in humans. For ten major pathogens, we tested PH and BH predictions about incidence and exposure-prevalence patterns. Compulsory-notification records (Brazil, 2006-2009) were used to estimate age-stratified ♂:♀ incidence rate ratios for the general population and across selected sociological contrasts. Exposure-prevalence odds ratios were derived from 82 published surveys. We estimated summary effect-size measures using random-effects models; our analyses encompass ∼0.5 million cases of disease or exposure. We found that, after puberty, disease incidence is male-biased in cutaneous and visceral leishmaniasis, schistosomiasis, pulmonary tuberculosis, leptospirosis, meningococcal meningitis, and hepatitis A. Severe dengue is female-biased, and no clear pattern is evident for typhoid fever. In leprosy, milder tuberculoid forms are female-biased, whereas more severe lepromatous forms are male-biased. For most diseases, male bias emerges also during infancy, when behavior is unbiased but sex steroid levels transiently rise. Behavioral factors likely modulate male-female differences in some diseases (the leishmaniases, tuberculosis, leptospirosis, or schistosomiasis) and age classes; however, average exposure-prevalence is significantly sex-biased only for Schistosoma and Leptospira. Our results closely match some key PH predictions and contradict some crucial BH predictions, suggesting that gender-specific behavior plays an overall secondary role in generating sex bias. Physiological differences, including the crosstalk between sex hormones and immune effectors, thus emerge as the main candidate drivers of gender differences in infectious disease susceptibility.
    PLoS ONE 01/2013; 8(4):e62390. · 3.53 Impact Factor

Full-text

View
0 Downloads
Available from