Dataset Information

Leprosy New Case Detection Trends and the Future Effect of Preventive Interventions in Para State, Brazil: A Modelling Study.

ABSTRACT: Leprosy remains a public health problem in Brazil. Although the overall number of new cases is declining, there are still areas with a high disease burden, such as Pará State in the north of the country. We aim to predict future trends in new case detection rate (NCDR) and explore the potential impact of contact tracing and chemoprophylaxis on NCDR in Pará State.We used SIMCOLEP, an existing individual-based model for the transmission and control of M. leprae, in a population structured by households. The model was quantified to simulate the population and observed NCDR of leprosy in Pará State for the period 1990 to 2014. The baseline scenario was the current control program, consisting of multidrug therapy, passive case detection, and active case detection from 2003 onwards. Future projections of the NCDR were made until 2050 given the continuation of the current control program (i.e. baseline). We further investigated the potential impact of two scenarios for future control of leprosy: 1) discontinuation of contact tracing; and 2) continuation of current control in combination with chemoprophylaxis. Both scenarios started in 2015 and were projected until 2050.The modelled NCDR in Pará State after 2014 shows a continuous downward trend, reaching the official elimination target of 10 cases per 100,000 population by 2030. The cessation of systematic contact tracing would not result in a higher NCDR in the long run. Systematic contact tracing in combination with chemoprophylaxis for contacts would reduce the NCDR by 40% and bring attainment of the elimination target two years forward to 2028.The NCDR of leprosy continues to decrease in Pará State. Elimination of leprosy as a public health problem could possibly be achieved around 2030, if the current control program is maintained. Providing chemoprophylaxis would decrease the NCDR further and would bring elimination forward by two years.

SUBMITTER: de Matos HJ

PROVIDER: S-EPMC4777416 | biostudies-other | 2016 Mar

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Leprosy New Case Detection Trends and the Future Effect of Preventive Interventions in Pará State, Brazil: A Modelling Study.

de Matos Haroldo José HJ Blok David J DJ de Vlas Sake J SJ Richardus Jan Hendrik JH

PLoS neglected tropical diseases 20160303 3

<h4>Background</h4>Leprosy remains a public health problem in Brazil. Although the overall number of new cases is declining, there are still areas with a high disease burden, such as Pará State in the north of the country. We aim to predict future trends in new case detection rate (NCDR) and explore the potential impact of contact tracing and chemoprophylaxis on NCDR in Pará State.<h4>Methods</h4>We used SIMCOLEP, an existing individual-based model for the transmission and control of M. leprae, ...[more]

PMID: 26938738

Similar Datasets

Project description:BackgroundMeasurement of malaria endemicity is typically based on vector or parasite measures. A complementary approach is the detection of parasite specific IgG antibodies. We determined the antibody levels and seroconversion rates to both P. vivax and P. falciparum merozoite antigens in individuals living in areas of varying P. vivax endemicity in Pará state, Brazilian Amazon region.Methodology/principal findingsThe prevalence of antibodies to recombinant antigens from P. vivax and P. falciparum was determined in 1,330 individuals. Cross sectional surveys were conducted in the north of Brazil in Anajás, Belém, Goianésia do Pará, Jacareacanga, Itaituba, Trairão, all in the Pará state, and Sucuriju, a free-malaria site in the neighboring state Amapá. Seroprevalence to any P. vivax antigens (MSP1 or AMA-1) was 52.5%, whereas 24.7% of the individuals were seropositive to any P. falciparum antigens (MSP1 or AMA-1). For P. vivax antigens, the seroconversion rates (SCR) ranged from 0.005 (Sucuriju) to 0.201 (Goianésia do Pará), and are strongly correlated to the corresponding Annual Parasite Index (API). We detected two sites with distinct characteristics: Goianésia do Pará where seroprevalence curve does not change with age, and Sucuriju where seroprevalence curve is better described by a model with two SCRs compatible with a decrease in force of infection occurred 14 years ago (from 0.069 to 0.005). For P. falciparum antigens, current SCR estimates varied from 0.002 (Belém) to 0.018 (Goianésia do Pará). We also detected a putative decrease in disease transmission occurred ∼29 years ago in Anajás, Goianésia do Pará, Itaituba, Jacareacanga, and Trairão.ConclusionsWe observed heterogeneity of serological indices across study sites with different endemicity levels and temporal changes in the force of infection in some of the sites. Our study provides further evidence that serology can be used to measure and monitor transmission of both major species of malaria parasite.

Project description:There is evidence that in southern US, leprosy is a zoonosis infecting wild Dasypus novemcinctus armadillos but the extent of this finding is unknown. This ecological study investigated leprosy in rural communities and in wild armadillos from the Brazilian Amazon. The study area was the Mamiá Lake of Coari municipality, Amazonas State, Northern region, a hyper endemic leprosy area where residents live on subsistence farming, fishing and armadillo hunting and its meat intake are frequent. The leprosy survey was conducted in sixteen communities by a visiting team of specialists. Local partakers provided wild armadillos to investigate M. leprae infection. Volunteers had complete dermato-neurological examination by a dermatologist with expertise in leprosy diagnosis, suspect skin lesions were biopsied for histopathology (Hematoxylin-eosin/HE, Fite-Faraco/FF staining); slit skin smears were collected. Armadillos' tissue fragments (skins, spleens, livers, lymph nodes, adrenal glands, others) were prepared for histopathology (HE/FF) and for M. leprae repetitive element-RLEP-qPCR. Among 176 volunteers, six new indeterminate leprosy cases were identified (incidence = 3.4%). Suspect skin sections and slit skin smears were negative for bacilli. Twelve wild D. novemcinctus were investigated (48 specimens/96 slides) and histopathological features of M. leprae infection were not found, except for one skin presenting unspecific inflammatory infiltrate suggestive of indeterminate leprosy. Possible traumatic neuroma, granuloma with epithelioid and Langhans cells, foreign-body granuloma were also identified. Granulomatous/non-granulomatous dermatitides were periodic-acid-Schiff/PAS negative for fungus. M. leprae-RLEP-qPCR was negative in all armadillos' tissues; no bacillus was found in histopathology. Our survey in rural communities confirmed the high endemicity for leprosy while one armadillo was compatible with paucibacillary M. leprae infection. At least in the highly endemic rural area of Coari, in the Brazilian Amazon region where infectious sources from untreated multibacillary leprosy are abundant, M. leprae infected armadillos may not represent a major source of infection nor a significant public health concern.

Dataset Information

Leprosy New Case Detection Trends and the Future Effect of Preventive Interventions in Para State, Brazil: A Modelling Study.

Publications

Leprosy New Case Detection Trends and the Future Effect of Preventive Interventions in Pará State, Brazil: A Modelling Study.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets