Angel G. Guevara

Interruption of infection transmission in the onchocerciasis focus of Ecuador leading to the cessation of ivermectin distribution.

Introduction: A clinically significant endemic focus of onchocerciasis existing in Esmeraldas Province, coastal Ecuador has been under an ivermectin mass drug administration program since 1991. The main transmitting vector in this area is the voracious blackfly, Simulium exiguum. This paper describes the assessments made that support the decision to cease mass treatment. Methodology and Principle Findings: Thirty-five rounds of ivermectin treatment occurred between 1991–2009 with 29 of these carrying >85% coverage. Following the guidelines set by WHO for ceasing ivermectin distribution the impact on parasite transmission was measured in the two vector species by an O-150 PCR technique standard for assessing for the presence of Onchocerca volvulus. Up to seven collection sites in three major river systems were tested on four occasions between 1995 and 2008. The infectivity rates of 65.0 (CI 39–101) and 72.7 (CI 42–116) in 1995 dropped to zero at all seven collection sites by 2008. Assessment for the presence of antibodies against O. volvulus was made in 2001, 2006, 2007 and 2008 using standard ELISA assays for detecting anti-Ov16 antibodies. None of total of 1810 children aged 1–15 years (between 82 and 98% of children present in the surveyed villages) tested in the above years were found to be carrying antibodies to this antigen. These findings were the basis for the cessation of mass drug treatment with ivermectin in 2009. Significance: This fulfillment of the criteria for cessation of mass distribution of ivermectin in the only known endemic zone of onchocerciasis in Ecuador moves the country into the surveillance phase of official verification for national elimination of transmission of infection. These findings indicate that ivermectin given twice a year with greater than 85% of the community can move a program to the final stages of verification of transmission interruption.

Comparison of S. stercoralis Serology Performed on Dried Blood Spots and on Conventional Serum Samples

Background: Dried blood spots (DBS) are used for epidemiological surveys on infectious diseases in settings where limited resources are available. In fact, DBS can help to overcome logistic difficulties for the collection, transport and storage of biological specimens. Objective: To evaluate the accuracy of Strongyloides stercoralis serology performed on DBS. Methods: A survey was proposed to children attending a school in the village of Borbon, Ecuador, and to their parents/guardians. Each participant gave consent to the collection of both serum and DBS specimens. DBS absorbed on filter papers were analyzed with a commercially available ELISA test for S. stercoralis antibodies, as well as with standard serology. The agreement between the two methods was assessed through the Cohen’s kappa coefficient. Results: The study sample was composed of 174 children and 61 adults, for a total of 235 serum and 235 DBS samples. The serology was positive in 31/235 (13%) serum samples, and in 27/235 (11%) DBS: 4 samples resulted discordant (positive at standard serology). Cohen’s kappa coefficient was 0.921 (95% CI 0.845 – 0.998), indicating a high rate of concordance. Conclusion: DBS are suitable for in field-surveys requiring serological testing for S. stercoralis.

Itraconazole in the treatment of New World mucocutaneous leishmaniasis

Background  A well‐tolerated oral drug is required for the treatment of mucocutaneous leishmaniasis (MCL). Current parenteral treatment regimens with pentavalent antimonials are associated with marked toxicity and significant rates of relapse.

A rapid molecular diagnosis of cutaneous leishmaniasis by colorimetric malachite green-loop-mediated isothermal amplification (LAMP) combined with an FTA card as a direct sampling tool

Leishmaniasis remains one of the worlds most neglected diseases, and early detection of the infectious agent, especially in developing countries, will require a simple and rapid test. In this study, we established a quick, one-step, single-tube, highly sensitive loop-mediated isothermal amplification (LAMP) assay for rapid detection of Leishmania DNA from tissue materials spotted on an FTA card. An FTA-LAMP with pre-added malachite green was performed at 64°C for 60min using a heating block and/or water bath and DNA amplification was detected immediately after incubation. The LAMP assay had high detection sensitivity down to a level of 0.01 parasites per μl. The field- and clinic-applicability of the colorimetric FTA-LAMP assay was demonstrated with 122 clinical samples collected from patients suspected of having cutaneous leishmaniasis in Peru, from which 71 positives were detected. The LAMP assay in combination with an FTA card described here is rapid and sensitive, as well as simple to perform, and has great potential usefulness for diagnosis and surveillance of leishmaniasis in endemic areas.

Chagas Disease Has Not Been Controlled in Ecuador.

A recent study by Cartelle Gestal et al. reported an analysis of data from the Ministry of Public Health on the epidemiological situation of neglected tropical diseases in Ecuador [1]. Based on a misleading definition of Chagas disease cases not corresponding to that of the Ministry of Public Health [2], the authors concluded that the government had mounted successful control campaigns, and as a result Chagas disease (among others) had been effectively controlled as no cases in children under age five had been reported since 2009. Ecuador is thus identified as one of the first countries to control Chagas disease. While we certainly agree that efforts have been made in terms of Chagas disease surveillance and control campaigns in Ecuador, a more comprehensive analysis of available data, from both the Ministry of Public Health and the literature, provides a very different picture, and the claim that Chagas disease is controlled made by Cartelle Gestal et al. seems largely inadequate and sends an equivocal message which can undermine current control efforts. As mentioned in this study, the Chagas disease control program in the country was formally established in 2003–2004, in response to recommendations from a technical consultation through PAHO/WHO [3] and field studies [4,5]. This consultation and data provided a baseline to prioritize activities. It reported a national seroprevalence of Trypanosoma cruzi infection of 1.38%, corresponding to 165–170,000 seropositive patients in the country. Three regions were prioritized: the coastal region (seroprevalence of 1.99%), the Amazon region (1.75%) and the southern highlands (0.65%). The incidence was estimated at 36 cases/100,000 inhabitants/year, resulting in 4,400 new cases each year [3]. Today, the most recent estimates from the WHO suggest the presence of nearly 200,000 seropositive patients and a current incidence of 14 cases/100,000 inhabitants/year [6]. An in depth analysis of the complete records from the Ministry of Public Health from 2004–2014, indicates a total of 915 reported human cases in the country, with a major increase over the years followed by a decrease in the past two years [7]. This increase reflects the efforts at improving the epidemiologic surveillance program, but it is clear that there is still significant underreporting of cases in the country. Indeed, several independent and recent seroprevalence studies in different regions and communities point out relatively high levels of seroprevalence of T. cruzi infection (ranging from 0.6 to 13.3%), and persistent active parasite transmission, as evidenced by the detection of seropositive children [8–12]. Additionally, there are reports of Chagas disease cases in regions where the Ministry of Public Health has no records of patients, further highlighting current underreporting [5,11,12]. Furthermore, while during the last decade Ecuador has achieved near 100% blood screening coverage for T. cruzi infection, the 15 participating blood banks regularly report seropositive blood donors to the External Performance Evaluation of Serological Screening Program administered by the Pontifical Catholic University of Ecuador. The vector control program was effectively started in 2004. However, due to limited human and financial resources, there have been important variations in the geographic coverage of the surveillance and control activities from year to year [7]. Importantly, a total of 12 provinces have not been included in these activities, representing an area larger than the covered provinces. Therefore, the available data do not correspond to a systematic national coverage, and thus still present an incomplete picture of the current transmission of Chagas disease in Ecuador. In the 11 provinces in which surveillance and control activities have been performed, house infestation by triatomines is still observed in many regions [7,13]. While vector control activities have had a significant effect and allowed reducing the infestation level, particularly in coastal Ecuador, these need to be sustained to avoid reinfestation and provide long-term effects. Also, while insecticide spraying may be effective against Triatoma dimidiata, a possibly domiciliated species which is poised for elimination in Ecuador, alternative control strategies may be needed against intrusive triatomine species such as Rhodnius ecuadoriensis or Panstrongylus howardi or for occasional exposure outside of homes [14–19]. Moreover, no formal vector control intervention has been implemented in the Amazon region, where nearly half of the cases of the country seem to originate [7], and active transmission still occurs through triatomine species including Rhodnius robustus and R. pictipes [8,9]. Especially in the Amazon, human activities (deforestation, urbanization) disturb the natural balance between the vectors, their wild hosts and the parasite, favoring the emergence of new transmission cycles in which humans may be included [8,9,11,20]. An accurate description of the situation of Chagas disease in Ecuador should mention that access to diagnosis throughout the country is limited and case detection during the last two decades has been sporadic and geographically restricted. Indeed, only one laboratory in the whole country, at the Instituto Nacional de Investigacion en Salud Publica (INSPI), performs official confirmation of anti-T. cruzi seropositivity and releases Nifurtimox for the treament of patients. In fact, we believe that lack of awareness by health care personnel in areas with active vectorial transmission, combined with lack of diagnostic capacity elsewhere in the country, have resulted in a gross under reporting of cases in Ecuador. Taken together, these data and studies highlight that Chagas disease is all but controlled in Ecuador, contrary to what is stated by Cartelle Gestal et al. While it is clear that disease surveillance and vector control activities from the Ministry of Public Health have improved over the years, these need to (i) reach national coverage to ensure the inclusion of all endemic provinces, and (ii) be sustained to ensure that what has been achieved can result in long-term control of the disease. These represent a clear challenge at a time when the Ministry of Public Health is undergoing major structural reorganization and many of its activities are being decentralized or interrupted. Indeed, there is a decrease in reported human cases and in vector controls activities observed in the past two years in Ecuador [7], which may reflect the interruption of the National Chagas Program and the Servicio Nacional de Control y Vigilancia de Enfermedades Transmitidas por Vectores Artropodos (SNEM) in late 2015. Their actions have not been replaced yet, so that there is currently no Chagas vector control program in the country. This can strongly jeopardize the results achieved so far and may be a lost opportunity to eliminate vectorial transmission with domiciliated vectors in some regions of Ecuador. Finally, as in many other countries in Latin America, current activities for Chagas disease control in Ecuador still need to improve treatment access and care for Chagas disease patients [21–23] as well as to better understand the importance of congenital transmission in the epidemiology of the disease [9,24]. Thus, control of Chagas disease in the country will only be reached if the programs from the Ministry of Public Health are strengthened and expanded. The National Chagas disease control programs in other Latin America countries such as Brazil, Argentina, or Colombia (among others) can provide key examples of successful strategies for Chagas disease surveillance and control, as well as of the challenges encountered for their implementation. Additionally, research needs to be performed to further expand our understanding of triatomine infestation and T. cruzi transmission cycles in the different specific endemic areas, to help further tailor surveillance and interventions. More than claiming that Chagas disease is controlled, we need to promote further political commitment to sustain current achievements in Chagas disease surveillance and control in Ecuador and to ensure that the goals of the London declaration on neglected tropical diseases [25] are met in the near future.

An analysis of reported cases of leishmaniasis in the southern Ecuadorian Amazon region, 1986-2012

An analysis of reported cases of cutaneous leishmaniasis (CL) was performed using the data registered in the southern Ecuadorian Amazon region during 27 years from 1986 to 2012. The cases/subjects with both the suspected CL lesions and the amastigote-positive results were recruited for the analysis. The yearly occurrence of cases showed a markedly higher number during the six years, 1988 and 1993. After 1994 when the insecticide spraying campaign using helicopter in 1993-1994, the number dropped remarkably. Then, the yearly occurrence gradually fluctuated from 101 cases in 1996 to 11 in 2009, maintaining a low number of cases after the campaign. The monthly occurrence of cases showed a markedly high number during March and August, suggesting a correlation to the rainy season (months) in the areas. A statistical significance was found between the monthly average number of the CL case and the average precipitation (p=0.01474). It was suggested that the time of transmission of CL would depend on the rainy seasons at each endemic area of Ecuador, which has a diverse climatic feature depending on the geographic regions. Such information at given leishmaniasis-endemic areas of Ecuador would be important for the future planning of the disease control. Molecular analysis and characterization of clinical samples revealed the presence of Leishmania (Viannia) braziliensis.

Seroepidemiological Study of Chagas Disease in the Southern Amazon Region of Ecuador

To determine the extent of Trypanosoma cruzi infection and/or transmission in the southern Amazon region of Ecuador, three indigenous communities in the provinces of Pastaza and Morona Santiago were serosurveyed. ChagatestTM, Immunocomb®II and immunofluorescent (IF) assays were used. Among the 385 inhabitants examined, nine (2.34%) were seropositive for T. cruzi infection. Of the nine positive sera, four (44.4%) fall in the 10–19, one each in the 20–29, 30–39 and 40–49, and two in the 50–59 age groups. These results suggested the possible existence of an autochthonous active T. cruzi transmission in the region and provide the first serological evidence for T. cruzi infection in the southern province of Morona Santiago bordering Peru. Further studies are needed in these Amazonian provinces to ascertain the spread of T. cruzi infection in the area.

First Human Cases of Leishmania (Viannia) lainsoni Infection and a Search for the Vector Sand Flies in Ecuador

An epidemiological study of leishmaniasis was performed in Amazonian areas of Ecuador since little information on the prevalent Leishmania and sand fly species responsible for the transmission is available. Of 33 clinical specimens from patients with cutaneous leishmaniasis (CL), causative parasites were identified in 25 samples based on cytochrome b gene analysis. As reported previously, Leishmania (Viannia) guyanensis and L. (V.) braziliensis were among the causative agents identified. In addition, L. (V.) lainsoni, for which infection is reported in Brazil, Bolivia, Peru, Suriname, and French Guiana, was identified in patients with CL from geographically separate areas in the Ecuadorian Amazon, corroborating the notion that L. (V.) lainsoni is widely distributed in South America. Sand flies were surveyed around the area where a patient with L. (V.) lainsoni was suspected to have been infected. However, natural infection of sand flies by L. (V.) lainsoni was not detected. Further extensive vector searches are necessary to define the transmission cycle of L. (V.) lainsoni in Ecuador.

First description of trypanosoma cruzi human infection in Esmeraldas province, Ecuador

Chagas disease was described in Ecuador in 1930 in the province of Guayas and thereafter in various provinces. Triatomine were reported in the province of Esmeraldas but no human infection has been described. Here we report the first evidence that the disease does exist in the province of Esmeraldas. In indigenous Awá communities located in the northwest jungle of the Esmeraldas province, 144 individuals were tested using ELISA and PCR for T.cruzi of which 5 (3.47%) were positive. Twenty eight triatomine were collected, 27 were Triatoma dispar and 1 Pastrongylus rufotuberculatus, T.cruzi was detected in 11 (42.3%) of 26 insects.

Esparganosis humana en el ecuador: informe de un caso en la província de esmeraldas

The second case of human sparganosis in Ecuador is reported in a male patient, of an indigenous tribe Chachi, from the province of Esmeraldas, who presented with a nodule localized in the left scapular region. Upon extirpation, a cestode classified as Spirometra was found, but the species could not be determined.The second case of human sparganosis in Ecuador is reported in a male patient, of an indigenous tribe Chachi, from the province of Esmeraldas, who presented with a nodule localized in the left scapular region. Upon extirpation, a cestode classified as Spirometra was found, but the species could not be determined.