Incidence of human Taenia solium larval infections in an Ecuadorian endemic area : implications for disease burden assessment and control

Background: Human cysticercosis is a zoonotic disease causing severe health disorders and even death. While prevalence data become available worldwide, incidence rate and cumulative incidence figures are lacking, which limits the understanding of the Taenia solium epidemiology. Methodology/Principal findings: A seroepidemiological cohort study was conducted in a south-Ecuadorian community to estimate the incidence rate of infection with and the incidence rate of exposure to T. solium based on antigen and antibody detections, respectively. The incidence rate of infection was 333.6 per 100,000 person-years (95% CI: [8.4–1,858] per 100,000 person-years) contrasting with a higher incidence rate of exposure 13,370 per 100,000 person-years (95% CI: [8,730–19,591] per 100,000 person-years). The proportion of infected individuals remained low and stable during the whole study year while more than 25% of the population showed at least one antibody seroconversion/seroreversion during the same time period. Conclusions/Significance: Understanding the transmission of T. solium is essential to develop ad hoc cost-effective prevention and control programs. The estimates generated here may now be incorporated in epidemiological models to simulate the temporal transmission of the parasite and the effects of control interventions on its life cycle. These estimates are also of high importance to assess the disease burden since incidence data are needed to make regional and global projections of morbidity and mortality related to cysticercosis

Gastrointestinal parasites in captive and free-ranging Cebus albifrons in the Western Amazon, Ecuador

Currently, there is a lack of surveys that report the occurrence of gastrointestinal parasites in the whiteheaded capuchin monkey (Cebus albifrons). We therefore assessed the presence and richness (= number of different parasite genera) of parasites in C. albifrons in wildlife refuges (n = 11) and in a free-ranging group near a human village (n = 15) in the Ecuadorian Amazon. In the 78 samples collected (median of 3 samples per animal), we identified a total of 6 genera of gastrointestinal parasites, representing protozoa, nematodes, acanthocephalans and cestodes. We observed a high prevalence (84%) across the 26 individuals, with the most prevalent parasite being Strongyloides sp. (76.9%), followed by Hymenolepis sp. (38.5%) and Prosthenorchis elegans (11.5%). We found Entamoeba histolytica/dispar/moskovskii/nuttalli and Capillaria sp. in only a minority of the animals (3.8%). In addition, we observed unidentified strongyles in approximately one-third of the animals (34.6%). We found a total of 6 parasite genera for the adult age group, which showed higher parasite richness than the subadult age group (5) and the juvenile age group (3). Faecal egg/cyst counts were not significantly different between captive and free-ranging individuals or between sexes or age groups. The free-ranging group had a higher prevalence than the captive group; however, this difference was not significant. The only genus common to captive and free-ranging individuals was Strongyloides sp. The high prevalence of gastrointestinal parasites and the presence of Strongyloides in both populations support results from previous studies in Cebus species. This high prevalence could be related to the high degree of humidity in the region. For the free-ranging group, additional studies are required to gain insights into the differences in parasite prevalence and intensity between age and sex groups. Additionally, our study demonstrated that a serial sampling of each individual increases the test sensitivity

Casos de brucelosis canina presentados en la provincia de Pichincha, Ecuador

La brucelosis canina, ampliamente distribuida en el mundo y con reportes de seroprevalencia de entre 6 % a 35 %, es considerada un problema de salud pública. Esta infección es producida por cuatro de las trece especies del género Brucella: B. canis, B. abortus, B. melitensis y B. suis, dependiendo de la cepa circulante en el área geográfica de estudio. El contagio ocurre principalmente por ingestión, inhalación o contacto con fetos abortados, placenta, secreciones vaginales o semen y también por vía transmamaria y placentaria. La aparición de casos de brucelosis canina marcó el inicio de este estudio con el análisis de la enfermedad mediante identificación del agente causal en dos escenarios epidemiológicos diferentes. En el primer escenario (2008), se tomaron sueros de 151 caninos de 34 fincas de la provincia de Pichincha (Ecuador), que se analizaron para detección de anticuerpos contra cepas lisas mediante Rosa de Bengala, sero-aglutinación lenta en tubo (SAT-EDTA) y ELISA indirecto. En el segundo escenario (2017 a 2019) y utilizando el Rapid test kit (C. Bru Ab Test) para detección de anticuerpos contra cepas rugosas, se analizaron diez sueros de caninos provenientes de clínicas veterinarias de la provincia de Pichincha (Ecuador). Para ambos escenarios se realizó biotipificación y genotipificación.Trabajo publicado en Cagliada, Maria del Pilar Lilia y Galosi, Cecilia Mónica (comps.). I Congreso de Microbiología Veterinaria. Libro de resúmenes. La Plata: Facultad de Ciencias Veterinarias, 2021.Facultad de Ciencias Veterinaria

Widespread resistance to macrocyclic lactones in cattle nematodes in Ecuador

The aim of the present study was to assess the resistance status of bovine gastrointestinal nematodes (GINs) against ivermectin (IVM) and fenbendazole (FBZ) in Ecuador. The study involved five cattle farms located in different topographic zones of the country. Anthelmintic efficacy was assessed by calculating the percentage of fecal egg counts reduction (FECR) after treatment. Additionally, DNA from pooled larval cultures was screened to ascertain benzimidazole resistance alleles. For animals treated with IVM, FECR percentages ranged from 0 to 68%, indicating the presence of highly resistant worms. The opposite was found for animals treated with FBZ, where FECR percentages were above 90% on all the farms tested. Pooled coprocultures revealed that Cooperia spp. were the predominant species pre and post-treatment although minor proportions of Haemonchus spp. and Ostertagia spp. were also identified. No mutations conferring resistance to benzimidazoles were identified in the beta-tubulin isotype 1 gene of the isolated Cooperia spp. worms, which is in line with the results of the FECR performed with FBZ. Overall, the present study highlights widespread resistance of bovine GINs to IVM but no to FBZ in Ecuador

New insight in lymnaeid snails (Mollusca, Gastropoda) as intermediate hosts of Fasciola hepatica (Trematoda, Digenea) in Ecuador

Fasciolosis is a widely distributed disease in livestock in South America but knowledge about the epidemiology and the intermediate hosts are scarce in Ecuador. During 3 months, lymnaeid snails were sampled (n=1482) in Pichincha province in two sites located in a highly endemic area. The snails were identified (based on morphology and ITS2 sequences) and the infection status was established through microscopic dissection and a multiplex PCR-based technique. If morphologic-based techniques were not useful to accurately named the one species collected, alignment study ascribed it to L. schirazensis. Rediae were observed in 1.75 % (26/1482) and Fasciola sp. DNA was detected in 6% (89/1482) of the collected snails. The COX1 region permitted the parasite species identification: F. hepatica. The relative sensitivity and specificity of the microscope related to the PCR results was 25.84% and 99.78% respectively. The mean size of the snails recorded positive for F. hepatica through crushing and microscopy was significantly higher than the mean size of negative snails. There was not such difference in PCR positive snails. The role of G. schirazensis as an intermediate host of F. hepatica in Ecuador is discussed and a hypothesis of an adaptation of the snail to the trematoda is formulated. For the first time, an epidemiological survey, based on molecular biology-based techniques assessed the role of lymnaeid snail in the epidemiology of fasciolosis in Ecuador

Is Galba schirazensis (Mollusca, Gastropoda) an intermediate host of Fasciola hepatica (Trematoda, Digenea) in Ecuador?

Fasciolosis is a widely distributed disease in livestock in South America but knowledge about the epidemiology and the intermediate hosts is relatively scarce in Ecuador. For three months, lymnaeid snails were sampled (n = 1482) in Pichincha Province at two sites located in a highly endemic area. Snails were identified (based on morphology and ITS-2 sequences) and the infection status was established through microscopic dissection and a multiplex polymerase chain reaction (PCR)-based technique. Techniques based on morphology were not useful to accurately name the collected snail species. Comparison with available DNA sequences showed that a single snail species was collected, Galba schirazensis. Live rediae were observed in 1.75% (26/1482) and Fasciola sp. DNA was detected in 6% (89/1482) of collected snails. The COX-1 region permitted identification of the parasite as Fasciola hepatica. The relative sensitivity and specificity of the microscope study, compared to PCR results, were 25.84% and 99.78%, respectively. The mean size of the snails recorded positive for F. hepatica through crushing and microscopy was significantly higher than the mean size of negative snails, but there was no such difference in PCR-positive snails. The role of G. schirazensis as an intermediate host of F. hepatica in Ecuador is discussed and the hypothesis of an adaptation of the parasite to this invasive snail is proposed. For the first time, an epidemiological survey based on molecular biology-based techniques assessed the possible role of lymnaeid snails in the epidemiology of fasciolosis in Ecuador

Prevalence of Fasciola hepatica infection in Galba cousini and Galba schirazensis from an Andean region of Ecuador

Some Lymnaeid snails are intermediate hosts of the liver fluke Fasciola hepatica, the causal agent of fasciolosis, a zoonotic parasitic disease. Human and livestock fasciolosis has been reported in a highland community located in the Chimborazo Province of the Ecuadorian Andes. However, no previous study has been carried out to identify which snail species act as intermediate host/s of F. hepatica. This study first aimed to identify the intermediate snail species and secondly to determine the prevalence of natural infection with F. hepatica in 230 lymnaeid snails sampled from irrigation and drainage canals in this area. The first objective entailed observations of shell morphology and internal organs as well as sequencing of the cytochrome oxidase subunit 1 (COI) gene. For the second objective, we used classic parasitological methods (observation of rediae and cercarial emission) and PCR amplification specie-specific to F. hepatica. COI haplotype networks were built to elucidate phylogeographic relationships between the snail populations from this highland community with other American and worldwide populations. We identified two lymnaeid Galba cousini and Galba schirazensis and found high infection rates of F. hepatica in G. cousini, but these differed according to the method used, with PCR showing a higher rate (61 ± 20%) compared to rediae observation (29 ± 17%). F. hepatica in G. schirazensis was identified only by DNA amplification. G. cousini populations were genetically structured by geographic distance whereas G. schirazensis populations showed very low genetic diversity. The higher abundance and infection rate of G. cousini compared to G. schirazensis suggests that the former is likely the specie responsible for F. hepatica transmission in this region.Fil: Celi Erazo, Maritza. Universidad Central del Ecuador; EcuadorFil: Alda, Maria del Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Université Montpellier II; Francia. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Montenegro Franco, María. Universidad Central del Ecuador; EcuadorFil: Pavon, Diego. Universidad Central del Ecuador; EcuadorFil: Minda Aluisa, Elizabeth. Universidad Central del Ecuador; EcuadorFil: Calvopiña, Manuel. Universidad de Las Américas.; EcuadorFil: Pointier, Jean Pierre. Université de Perpignan; Francia. Centre National de la Recherche Scientifique; FranciaFil: Hurtrez Boussès, Sylvie. Université Montpellier II; Francia. Centre National de la Recherche Scientifique; FranciaFil: Cevallos, William. Universidad Central del Ecuador; EcuadorFil: Benítez Ortíz, Washington. Universidad Central del Ecuador; EcuadorFil: Rodríguez Hidalgo, Richar. Universidad Central del Ecuador; Ecuado

Antigen and antibody seroprevalence figures (as based on the results of the Ag-ELISA and the EITB, respectively) by sex and by sampling round.

a<p>CI = Binomial exact 95% Confidence Intervals; SR = sampling round;</p>b<p>SR 1 = June 2009 sampling,</p>c<p>SR 2 = November 2009 Sampling;</p>d<p>SR 3 = July 2010 Sampling.</p

Results of the change point analysis with a change point at 30 years old.

<p>The vertical dotted/lined line represents the change point at 30 years old; white bars represent proportions of Ab seroconversion whereas grey bars represent proportions of Ab seroreversion; vertical error bars represent the upper and lower limits for the 95% binomial exact confidence interval.</p

Proportions of Ab seroconversion and seroreversion by time period.

<p>White bars represent proportions of Ab seroconversion whereas grey bars represent proportions of Ab seroreversion; vertical error bars represent the upper and lower limits for the 95% binomial exact confidence interval; Period 1 stands for the period between Sampling round 1 and sampling round 2 (June–November 2009); Period 2 stands for the period between sampling round 2 and sampling round 3 (November 2009–July 2010) and Period 3 stands for the period between sampling round 1 and sampling round 3 (June 2009–July 2010).</p