Yaws elimination in Ecuador: Findings of a serological survey of children in Esmeraldas province to evaluate interruption of transmission.

BACKGROUND: The WHO roadmap for neglected tropical diseases includes yaws eradication requiring certification of elimination of transmission in all endemic and formerly endemic countries worldwide. A community-based programme for yaws control was considered to have achieved elimination of the infection in the endemic focus in Ecuador after 1993. We did a serosurvey of children in this focus to provide evidence for interruption of transmission. METHODS: Survey of serum samples collected from children aged 2 to 15 years living in the formerly endemic and in geographically contiguous areas. A convenience sample of sera collected between 2005 were 2017 from non-yaws studies, were analyzed using immunochromatic rapid tests to screen (OnSite Syphilis Ab Combo Rapid Test) for Treponema pallidum-specific antibodies and confirm (DPP Syphilis Screen and Confirm) seroreactivity based on the presence antibodies to treponemal and non-treponemal antigens. RESULTS: Seroreactivity was confirmed in 6 (0.14%, 95% CI 0.06-0.30) of 4,432 sera analyzed and was similar in formerly endemic (0.11%, (95% CI 0.01-0.75) and non-endemic (0.14%, 95% CI 0.06-0.34) communities. All seroreactors were of Afro-Ecuadorian ethnicity and most were male (4/6) and aged 10 or more years (5/6), the latter possibly indicating venereal syphilis. Only 1 seroreactor lived in a community in the Rio Santiago, that was formerly hyperendemic for yaws. CONCLUSION: We observed very low levels of treponemal transmission in both formerly endemic and non-endemic communities which might be indicative of congenital or venereal syphilis and, if yaws, would likely be insufficient to maintain transmission of this endemic childhood infection. Additional surveys of children aged 1 to 5 years are planned in Rio Santiago communities to exclude yaws transmission.

Recurrent Plasmodium vivax Cases of Both Short and Long Latency Increased with Transmission Intensity and Were Distributed Year-Round in the Most Affected Municipalities of the RACCN, Nicaragua, 2013-2018.

The characteristics of P. vivax recurrent episodes were examined using a centralized secondary source of malaria records in Nicaragua and in the two most affected municipalities in the RACCN. The study of 36,787 malaria cases due to P. vivax or P. falciparum revealed that, nationwide, 3624 patients had at least one recurrent infection. This was achieved by matching names, gender, age, community/municipality, ethnicity, etc. P. vivax was responsible for 88% of recurrent infections of 25-450 days of latency (51.9% were women and 48.1% were men), and these were assumed to be relapse episodes. Of them, 88.2% and 4.4% occurred in the municipalities of Puerto Cabezas and Rosita, respectively. The proportion of P. vivax patients having presumed relapse episodes rose with elevated transmission rates in both municipalities, reaching 7% in Rosita (2017) and 14.5% in Puerto Cabezas (2018). In both areas, relapse episodes were evident over time and were characterized by the production of a continuous stippling pattern with a slope evolving from one transmission peak to the next. During the dry season, short-latency relapse episodes were more robust, while long-latency ones increased just before the P. vivax transmission season began, with a high proportion of long-latency relapses during this period. The abundance of recurrent P. vivax infections, the wide range of relapse latency lengths, and temporal distribution tended to favor year-round transmission. It is necessary to evaluate compliance with and the effectiveness of primaquine treatment and contemplate the use of an alternative drug, among other actions.

Detección de Leptospira spp. en animales y muestras ambientales de áreas peridomésticas en Nicaragua

[RESUMEN]. Objetivo. El objetivo de este estudio fue conocer las características epidemiológicas de la leptospirosis en animales domésticos y en los casos de leptospirosis humana en áreas peridomésticas en Nicaragua entre 2014 y 2016. Métodos. Las muestras se extrajeron en áreas donde se confirmaron casos en humanos utilizando un muestreo no probabilístico en 10 de los 17 departamentos del país. Se incluyeron 112 muestras de orina de animales domésticos, 129 muestras de agua y 69 de tierra para aislar leptospiras en medio Ellinghausen-McCullough-Johnson-Harris (EMJH). Además, se aplicó la prueba de microaglutinación (MAT) en 263 muestras de suero de animales y 88 aislados se analizaron mediante PCR. Resultados. En 32,6% (101/310) de las muestras se aislaron espiroquetas, 23,2% (26/112) se aislaron en la orina de animales domésticos, 47,3% (61/129), en las muestras de agua y 20,3 % (14/69), en las de tierra. El análisis de aislamiento mostró diferencias significativas (P < 0,05) entre los departamentos para los diferentes tipos de muestras, y el aislamiento fue más frecuente en agua que en tierra (OR = 3,49; IC95%: 1,56-7,80). El 14,1% (37/263) de los animales fueron reactores en la prueba de microaglutinación. El serogrupo más frecuente fue Icterohaemorrhagiae (40%). En el análisis con la PCR para identificar leptospiras de las especies patógenas 10,2% (9/88) de los aislamientos fueron positivos. Conclusiones. Esta investigación demuestra que los animales domésticos y el ambiente desempeñan un papel importante en la aparición de brotes de la leptospirosis y confirma el comportamiento endémico de la enfermedad en Nicaragua.

[ABSTRACT]. Objective. The objective of this study was to determine the epidemiological characteristics of leptospirosis in pets and in humans in peridomestic settings in Nicaragua between 2014 and 2016. Methods. The samples were taken in areas where cases were confirmed in humans using non-probabilistic sampling in 10 of the country’s 17 departments. This included 112 urine samples from pets, 129 water samples, and 69 soil samples in order to isolate leptospires in Ellinghausen-McCullough-Johnson-Harris (EMJH) medium. Furthermore, the microscopic agglutination test (MAT) was applied to 263 samples of animal serum, and 88 isolates were analyzed using PCR. Results. In 32.6% (101/310) of the samples, spirochetes were isolated: 23.2% (26/112) in the pet urine, 47.3% (61/129) in water samples, and 20.3% (14/69) in soil samples. Isolation analysis showed significant differences (p<0.05) between departments for the different types of samples, and isolation was more frequent in water than in soil (OR = 3.49; CI95%: 1.56-7.80). In total, 14.1% (37/263) of the animals were reactors in the microscopic agglutination test. The most frequent serogroup was Icterohaemorrhagiae (40%). PCR analysis to identify pathogenic species of leptospires resulted in 10.2% (9/88) positive isolations. Conclusions. This research demonstrates that pets and environment conditions play an important role in the emergence of outbreaks of leptospirosis, and confirms the endemic behavior of the disease in Nicaragua.

[RESUMO]. Objetivo. Descrever as características epidemiológicas da leptospirose em animais domésticos e em casos de leptospirose humana em áreas peridomiciliares na Nicarágua entre 2014 e 2016. Métodos. As amostras foram coletadas por amostragem não probabilística em áreas com casos confirmados de leptospirose humana em 10 das 17 províncias do país. Foram analisadas 112 amostras de urina de animais domésticos, 129 amostras de água e 69 amostras de solo com o uso do meio de cultura padrão para o isolamento de leptospiras (Ellinghausen-McCullough-Johnson-Harris, EMJH). Além disso, foi realizado o teste de aglutinação microscópica em 263 amostras séricas de animais e 88 isolados foram analisados com a técnica de PCR. Resultados. Em 32,6% (101/310) das amostras foram isoladas espiroquetas, sendo 23,2% (26/112) isoladas na urina de animais domésticos, 47,3% (61/129) nas amostras de água e 20,3% (14/69) nas amostras de solo. Houve diferença significativa (P < 0,05) entre as províncias no isolamento nos diferentes tipos de amostras analisadas, sendo o isolamento mais frequente nas amostras de água que de solo (OR = 3,49; IC95%: 1, 56–7,80). Reatividade no teste de aglutinação microscópica foi observada em 14,1% (37/263) das amostras de animais. O sorogrupo mais frequentemente isolado foi Icterohaemorrhagiae (40%). A técnica de PCR demonstrou que 10,2% (9/88) dos isolados eram positivos para espécies patogênicas de leptospiras. Conclusões. Esta pesquisa demonstra que os animais domésticos e o entorno têm papel importante no surgimento de surtos de leptospirose e confirma o comportamento endêmico da doença na Nicarágua.

[Detection of Leptospire spp. in animals and in environmental samples from peridomestic areas in NicaraguaDetecção de Leptospira spp. em animais e em amostras ambientais de áreas peridomiciliares na Nicarágua]. / Detección de Leptospira spp. en animales y muestras ambientales de áreas peridomésticas en Nicaragua.

OBJECTIVE: The objective of this study was to determine the epidemiological characteristics of leptospirosis in pets and in humans in peridomestic settings in Nicaragua between 2014 and 2016. METHODS: The samples were taken in areas where cases were confirmed in humans using non-probabilistic sampling in 10 of the country's 17 departments. This included 112 urine samples from pets, 129 water samples, and 69 soil samples in order to isolate leptospires in Ellinghausen-McCullough-Johnson-Harris (EMJH) medium. Furthermore, the microscopic agglutination test (MAT) was applied to 263 samples of animal serum, and 88 isolates were analyzed using PCR. RESULTS: In 32.6% (101/310) of the samples, spirochetes were isolated: 23.2% (26/112) in the pet urine, 47.3% (61/129) in water samples, and 20.3% (14/69) in soil samples. Isolation analysis showed significant differences (p<0.05) between departments for the different types of samples, and isolation was more frequent in water than in soil (OR = 3.49; CI95%: 1.56-7.80). In total, 14.1% (37/263) of the animals were reactors in the microscopic agglutination test. The most frequent serogroup was Icterohaemorrhagiae (40%). PCR analysis to identify pathogenic species of leptospires resulted in 10.2% (9/88) positive isolations. CONCLUSIONS: This research demonstrates that pets and environment conditions play an important role in the emergence of outbreaks of leptospirosis, and confirms the endemic behavior of the disease in Nicaragua.

OBJETIVO: Descrever as características epidemiológicas da leptospirose em animais domésticos e em casos de leptospirose humana em áreas peridomiciliares na Nicarágua entre 2014 e 2016. MÉTODOS: As amostras foram coletadas por amostragem não probabilística em áreas com casos confirmados de leptospirose humana em 10 das 17 províncias do país. Foram analisadas 112 amostras de urina de animais domésticos, 129 amostras de água e 69 amostras de solo com o uso do meio de cultura padrão para o isolamento de leptospiras (Ellinghausen-McCullough-Johnson-Harris, EMJH). Além disso, foi realizado o teste de aglutinação microscópica em 263 amostras séricas de animais e 88 isolados foram analisados com a técnica de PCR. RESULTADOS: Em 32,6% (101/310) das amostras foram isoladas espiroquetas, sendo 23,2% (26/112) isoladas na urina de animais domésticos, 47,3% (61/129) nas amostras de água e 20,3% (14/69) nas amostras de solo. Houve diferença significativa (P < 0,05) entre as províncias no isolamento nos diferentes tipos de amostras analisadas, sendo o isolamento mais frequente nas amostras de água que de solo (OR = 3,49; IC95%: 1,56­7,80). Reatividade no teste de aglutinação microscópica foi observada em 14,1% (37/263) das amostras de animais. O sorogrupo mais frequentemente isolado foi Icterohaemorrhagiae (40%). A técnica de PCR demonstrou que 10,2% (9/88) dos isolados eram positivos para espécies patogênicas de leptospiras. CONCLUSÕES: Esta pesquisa demonstra que os animais domésticos e o entorno têm papel importante no surgimento de surtos de leptospirose e confirma o comportamento endêmico da doença na Nicarágua.

Detección de Leptospira spp. en animales y muestras ambientales de áreas peridomésticas en Nicaragua / Detection of Leptospire spp. in animals and in environmental samples from peridomestic areas in Nicaragua / Detecção de Leptospira spp. em animais e em amostras ambientais de áreas peridomiciliares na Nicarágua

RESUMEN Objetivo El objetivo de este estudio fue conocer las características epidemiológicas de la leptospirosis en animales domésticos y en los casos de leptospirosis humana en áreas peridomésticas en Nicaragua entre 2014 y 2016. Métodos Las muestras se extrajeron en áreas donde se confirmaron casos en humanos utilizando un muestreo no probabilístico en 10 de los 17 departamentos del país. Se incluyeron 112 muestras de orina de animales domésticos, 129 muestras de agua y 69 de tierra para aislar leptospiras en medio Ellinghausen-McCullough-Johnson-Harris (EMJH). Además, se aplicó la prueba de microaglutinación (MAT) en 263 muestras de suero de animales y 88 aislados se analizaron mediante PCR. Resultados En 32,6% (101/310) de las muestras se aislaron espiroquetas, 23,2% (26/112) se aislaron en la orina de animales domésticos, 47,3% (61/129), en las muestras de agua y 20,3 % (14/69), en las de tierra. El análisis de aislamiento mostró diferencias significativas (P < 0,05) entre los departamentos para los diferentes tipos de muestras, y el aislamiento fue más frecuente en agua que en tierra (OR = 3,49; IC95%: 1,56-7,80). El 14,1% (37/263) de los animales fueron reactores en la prueba de microaglutinación. El serogrupo más frecuente fue Icterohaemorrhagiae (40%). En el análisis con la PCR para identificar leptospiras de las especies patógenas 10,2% (9/88) de los aislamientos fueron positivos. Conclusiones Esta investigación demuestra que los animales domésticos y el ambiente desempeñan un papel importante en la aparición de brotes de la leptospirosis y confirma el comportamiento endémico de la enfermedad en Nicaragua.

ABSTRACT Objective The objective of this study was to determine the epidemiological characteristics of leptospirosis in pets and in humans in peridomestic settings in Nicaragua between 2014 and 2016. Methods The samples were taken in areas where cases were confirmed in humans using non-probabilistic sampling in 10 of the country's 17 departments. This included 112 urine samples from pets, 129 water samples, and 69 soil samples in order to isolate leptospires in Ellinghausen-McCullough-Johnson-Harris (EMJH) medium. Furthermore, the microscopic agglutination test (MAT) was applied to 263 samples of animal serum, and 88 isolates were analyzed using PCR. Results In 32.6% (101/310) of the samples, spirochetes were isolated: 23.2% (26/112) in the pet urine, 47.3% (61/129) in water samples, and 20.3% (14/69) in soil samples. Isolation analysis showed significant differences (p<0.05) between departments for the different types of samples, and isolation was more frequent in water than in soil (OR = 3.49; CI95%: 1.56-7.80). In total, 14.1% (37/263) of the animals were reactors in the microscopic agglutination test. The most frequent serogroup was Icterohaemorrhagiae (40%). PCR analysis to identify pathogenic species of leptospires resulted in 10.2% (9/88) positive isolations. Conclusions This research demonstrates that pets and environment conditions play an important role in the emergence of outbreaks of leptospirosis, and confirms the endemic behavior of the disease in Nicaragua.

RESUMO Objetivo Descrever as características epidemiológicas da leptospirose em animais domésticos e em casos de leptospirose humana em áreas peridomiciliares na Nicarágua entre 2014 e 2016. Métodos As amostras foram coletadas por amostragem não probabilística em áreas com casos confirmados de leptospirose humana em 10 das 17 províncias do país. Foram analisadas 112 amostras de urina de animais domésticos, 129 amostras de água e 69 amostras de solo com o uso do meio de cultura padrão para o isolamento de leptospiras (Ellinghausen-McCullough-Johnson-Harris, EMJH). Além disso, foi realizado o teste de aglutinação microscópica em 263 amostras séricas de animais e 88 isolados foram analisados com a técnica de PCR. Resultados Em 32,6% (101/310) das amostras foram isoladas espiroquetas, sendo 23,2% (26/112) isoladas na urina de animais domésticos, 47,3% (61/129) nas amostras de água e 20,3% (14/69) nas amostras de solo. Houve diferença significativa (P < 0,05) entre as províncias no isolamento nos diferentes tipos de amostras analisadas, sendo o isolamento mais frequente nas amostras de água que de solo (OR = 3,49; IC95%: 1,56-7,80). Reatividade no teste de aglutinação microscópica foi observada em 14,1% (37/263) das amostras de animais. O sorogrupo mais frequentemente isolado foi Icterohaemorrhagiae (40%). A técnica de PCR demonstrou que 10,2% (9/88) dos isolados eram positivos para espécies patogênicas de leptospiras. Conclusões Esta pesquisa demonstra que os animais domésticos e o entorno têm papel importante no surgimento de surtos de leptospirose e confirma o comportamento endêmico da doença na Nicarágua.

Socioeconomic factors and vulnerability to outbreaks of leptospirosis in Nicaragua.

Leptospirosis is an epidemic-prone zoonotic disease that occurs worldwide, with more than 500,000 human cases reported annually. It is influenced by environmental and socioeconomic factors that affect the occurrence of outbreaks and the incidence of the disease. Critical areas and potential drivers for leptospirosis outbreaks have been identified in Nicaragua, where several conditions converge and create an appropriate scenario for the development of leptospirosis. The objectives of this study were to explore possible socioeconomic variables related to leptospirosis critical areas and to construct and validate a vulnerability index based on municipal socioeconomic indicators. Municipalities with lower socioeconomic status (greater unsatisfied basic needs for quality of the household and for sanitary services, and higher extreme poverty and illiteracy rates) were identified with the highest leptospirosis rates. The municipalities with highest local vulnerability index should be the priority for intervention. A distinction between risk given by environmental factors and vulnerability to risk given by socioeconomic conditions was shown as important, which also applies to the "causes of outbreaks" and "causes of cases".

Molecular analysis of chloroquine and sulfadoxine-pyrimethamine resistance-associated alleles in Plasmodium falciparum isolates from Nicaragua.

Chloroquine (CQ) is used as a first-line therapy for the treatment of Plasmodium falciparum malaria in Nicaragua. We investigated the prevalence of molecular markers associated with CQ and sulfadoxine-pyrimethamine (SP) resistance in P. falciparum isolates obtained from the North Atlantic Autonomous Region of Nicaragua. Blood spots for this study were made available from a CQ and SP drug efficacy trial conducted in 2005 and also from a surveillance study performed in 2011. Polymorphisms in P. falciparum CQ resistance transporter, dihydrofolate reductase, and dihydropteroate synthase gene loci that are associated with resistance to CQ, pyrimethamine, and sulfadoxine, respectively, were detected by DNA sequencing. In the 2005 dataset, only 2 of 53 isolates had a CQ resistance allele (CVIET), 2 of 52 had a pyrimethamine resistance allele, and 1 of 49 had a sulfadoxine resistance allele. In the 2011 dataset, none of 45 isolates analyzed had CQ or SP resistance alleles.

Genetic structure of Plasmodium falciparum populations across the Honduras-Nicaragua border.

BACKGROUND: The Caribbean coast of Central America remains an area of malaria transmission caused by Plasmodium falciparum despite the fact that morbidity has been reduced in recent years. Parasite populations in that region show interesting characteristics such as chloroquine susceptibility and low mortality rates. Genetic structure and diversity of P. falciparum populations in the Honduras-Nicaragua border were analysed in this study. METHODS: Seven neutral microsatellite loci were analysed in 110 P. falciparum isolates from endemic areas of Honduras (n = 77) and Nicaragua (n = 33), mostly from the border region called the Moskitia. Several analyses concerning the genetic diversity, linkage disequilibrium, population structure, molecular variance, and haplotype clustering were conducted. RESULTS: There was a low level of genetic diversity in P. falciparum populations from Honduras and Nicaragua. Expected heterozigosity (H(e)) results were similarly low for both populations. A moderate differentiation was revealed by the F(ST) index between both populations, and two putative clusters were defined through a structure analysis. The main cluster grouped most of samples from Honduras and Nicaragua, while the second cluster was smaller and included all the samples from the Siuna community in Nicaragua. This result could partially explain the stronger linkage disequilibrium (LD) in the parasite population from that country. These findings are congruent with the decreasing rates of malaria endemicity in Central America.

Molecular epidemiology of Plasmodium vivax in Latin America: polymorphism and evolutionary relationships of the circumsporozoite gene.

BACKGROUND: The origins and dispersal of Plasmodium vivax to its current worldwide distribution remains controversial. Although progress on P. vivax genetics and genomics has been achieved worldwide, information concerning New World parasites remains fragmented and largely incomplete. More information on the genetic diversity in Latin America (LA) is needed to better explain current patterns of parasite dispersion and evolution. METHODS: Plasmodium vivax circumsporozoite protein gene polymorphism was investigated using polymerase chain reaction amplification and restriction fragment length polymorphism (PCR-RFLP), and Sanger sequencing in isolates from the Pacific Ocean coast of Mexico, Nicaragua, and Peru. In conjunction with worldwide sequences retrieved from the Genbank, mismatch distribution analysis of central repeat region (CRR), frequency estimation of unique repeat types and phylogenetic analysis of the 3' terminal region, were performed to obtain an integrative view of the genetic relationships between regional and worldwide isolates. RESULTS: Four RFLP subtypes, vk210a, b, c and d were identified in Southern Mexico and three subtypes vk210a, e and f in Nicaragua. The nucleotide sequences showed that Mexican vk210a and all Nicaraguan isolates were similar to other American parasites. In contrast, vk210b, c and d were less frequent, had a domain ANKKAEDA in their carboxyl end and clustered with Asian isolates. All vk247 isolates from Mexico and Peru had identical RFLP pattern. Their nucleotide sequences showed two copies of GGQAAGGNAANKKAGDAGA at the carboxyl end. Differences in mismatch distribution parameters of the CRR separate vk247 from most vk210 isolates. While vk247 isolates display a homogeneous pattern with no geographical clustering, vk210 isolates display a heterogeneous geographically clustered pattern which clearly separates LA from non-American isolates, except vk210b, c and d from Southern Mexico. CONCLUSIONS: The presence of vk210a in Mexico and vk210e, f and g in Nicaragua are consistent with other previously reported LA isolates and reflect their circulation throughout the continent. The vk210b, c and d are novel genotypes in LA. Their genetic relationships and low variability within these vk210 and/or within the vk247 parasites in Southern Mexico suggest its recent introduction and/or recent expansion to this region. The global analysis of P. vivax csp suggests this parasite introduction to the region and likely LA by different independent events.

Leptospirosis outbreaks in Nicaragua: identifying critical areas and exploring drivers for evidence-based planning.

Leptospirosis is an epidemic-prone zoonotic disease that occurs worldwide. In Central America, leptospirosis outbreaks have been reported in almost all countries; Nicaragua in particular has faced several outbreaks. The objective of this study was to stratify the risk and identify "critical areas" for leptospirosis outbreaks in Nicaragua, and to perform an exploratory analysis of potential "drivers". This ecological study includes the entire country (153 municipalities). Cases from 2004 to 2010 were obtained from the country's health information system, demographic and socioeconomic variables from its Census, and environmental data from external sources. Criteria for risk stratification of leptospirosis were defined. Nicaragua reported 1,980 cases of leptospirosis during this period, with the highest percentage of cases (26.36%) in León, followed by Chinandega (15.35%). Among the 153 municipalities, 48 were considered critical areas, 85 were endemic and 20 silent. Using spatial and statistical analysis, the variable presenting the most evident pattern of association with critical areas defined by top quintile of incidence rate is the percentage of municipal surface occupied by the soil combination of cambisol (over pyroclastic and lava bedrock) and andosol (over a volcanic ashes foundation). Precipitation and percentage of rural population are also associated with critical areas. This methodology and findings could be used for Nicaragua's Leptospirosis Intersectoral Plan, and to identify possible risk areas in other countries with similar drivers.