Current status of the knowledge on the epidemiology of tungiasis in the Americas.

Objectives: To present the state-of-the-knowledge on the epidemiology of tungiasis in the Region of the Americas. Methods: A search of publications on the epidemiology of tungiasis in the Americas was performed in PubMed and LILACS databases from January 2007 to June 2021. In addition, a manual literature search on articles on the epidemiology of tungiasis was performed. Results: A total of 83 articles were analyzed which contained relevant information on tungiasis cases and their geographical distribution, prevalence and risk factors, life cycle, sites where transmission takes place, and zoonotic aspects. The on-host and off-host life cycles have been researched in detail. In certain contexts, the whole life cycle is completed indoors enabling transmission around the whole year. Cases were reported from 10 countries; 71% of them were from Brazil. In the general population, the prevalence varied between 1.0% and 82.6% according to the settings. Age-specific prevalence indicated that children and the elderly bear the highest disease burden. Risk factor studies indicate that tungiasis is associated with severe poverty. Conclusions: In the Americas, there are important gaps in information and knowledge of tungiasis. Understanding the burden, epidemiology, distribution, magnitude, related risk factors, and reservoirs, among others, is needed to develop and implement integrated control measures tailored to the context and patterns of transmission in the affected communities.

Risk factors associated with Chagas disease in pregnant women in Santander, a highly endemic Colombian area.

OBJECTIVE: To determine the prevalence and risk factors associated with Chagas disease in pregnant women in an endemic area of Santander, Colombia. METHODS: Cross-sectional study included 23 municipalities of Santander, Colombia. Serological IFAT and ELISA tests were undertaken to detect IgG anti- Trypanosoma cruzi. A questionnaire was conducted for assessing the risk factors of each participant. Newborns were evaluated at birth and followed up to 1 year of age to determine congenital infection. RESULTS: An overall prevalence of 3.2% (95% CI 2.4-4.2) among 1518 pregnant women was detected. Prevalences by provinces were as follows: Guanentina: 6.0% (95% CI 4.1-8.5), García Rovira: 2.9% (95% CI: 1.5-4.8) and Comunera: 0.4% (0.4-2.3). The main risk factors identified were age >32 years old (OR: 2.1; 95% CI: 1.1-3.9); currently having a thatched roof (OR: 11.8; CI95% 2.2-63.2) and a thatched roof during childhood (OR: 3.0; 95% CI: 1.4-6.6); having below primary school education level (OR: 4.6; 95% CI: 2.2-9.5); and a history of a close contact with the vector (triatomine bugs) at least once during their lifetime (OR: 6.9; 95% CI: 3.7-12.9). No congenital cases were detected by parasitological or serological techniques. CONCLUSIONS: Prevalence of Chagas disease in pregnant women is a potential source of infection in this Colombian endemic area. The main risk factors associated with seropositivity were related to conditions favouring the contact with the vector. The results show that it is necessary to continue an active surveillance in order to offer diagnosis and treatment to mothers and their newborns in addition to screening to pregnant women from endemic areas.

Climate change, malaria and neglected tropical diseases: a scoping review.

To explore the effects of climate change on malaria and 20 neglected tropical diseases (NTDs), and potential effect amelioration through mitigation and adaptation, we searched for papers published from January 2010 to October 2023. We descriptively synthesised extracted data. We analysed numbers of papers meeting our inclusion criteria by country and national disease burden, healthcare access and quality index (HAQI), as well as by climate vulnerability score. From 42 693 retrieved records, 1543 full-text papers were assessed. Of 511 papers meeting the inclusion criteria, 185 studied malaria, 181 dengue and chikungunya and 53 leishmaniasis; other NTDs were relatively understudied. Mitigation was considered in 174 papers (34%) and adaption strategies in 24 (5%). Amplitude and direction of effects of climate change on malaria and NTDs are likely to vary by disease and location, be non-linear and evolve over time. Available analyses do not allow confident prediction of the overall global impact of climate change on these diseases. For dengue and chikungunya and the group of non-vector-borne NTDs, the literature privileged consideration of current low-burden countries with a high HAQI. No leishmaniasis papers considered outcomes in East Africa. Comprehensive, collaborative and standardised modelling efforts are needed to better understand how climate change will directly and indirectly affect malaria and NTDs.

Noninferiority of miltefosine versus meglumine antimoniate for cutaneous leishmaniasis in children.

BACKGROUND: Children have a lower response rate to antimonial drugs and higher elimination rate of antimony (Sb) than adults. Oral miltefosine has not been evaluated for pediatric cutaneous leishmaniasis. METHODS: A randomized, noninferiority clinical trial with masked evaluation was conducted at 3 locations in Colombia where Leishmania panamensis and Leishmania guyanensis predominated. One hundred sixteen children aged 2-12 years with parasitologically confirmed cutaneous leishmaniasis were randomized to directly observed treatment with meglumine antimoniate (20 mg Sb/kg/d for 20 days; intramuscular) (n = 58) or miltefosine (1.8-2.5 mg/kg/d for 28 days; by mouth) (n = 58). Primary outcome was treatment failure at or before week 26 after initiation of treatment. Miltefosine was noninferior if the proportion of treatment failures was ≤15% higher than achieved with meglumine antimoniate (1-sided test, α = .05). RESULTS: Ninety-five percent of children (111/116) completed follow-up evaluation. By intention-to-treat analysis, failure rate was 17.2% (98% confidence interval [CI], 5.7%-28.7%) for miltefosine and 31% (98% CI, 16.9%-45.2%) for meglumine antimoniate. The difference between treatment groups was 13.8%, (98% CI, -4.5% to 32%) (P = .04). Adverse events were mild for both treatments. CONCLUSIONS: Miltefosine is noninferior to meglumine antimoniate for treatment of pediatric cutaneous leishmaniasis caused by Leishmania (Viannia) species. Advantages of oral administration and low toxicity favor use of miltefosine in children. CLINICAL TRIAL REGISTRATION: NCT00487253.

Progress towards elimination of lymphatic filariasis in the Americas region.

In South and Central America, lymphatic filariasis (LF) is caused by Wuchereria bancrofti, which is transmitted by Culex quinquefasciatus, the only vector species in this region. Of the seven countries considered endemic for LF in the Americas in the last decade, Costa Rica, Suriname and Trinidad and Tobago were removed from the World Health Organization list in 2011. The remaining countries, Brazil, Dominican Republic, Guyana and Haiti, have achieved important progress in recent years. Brazil was the first country in the Americas to stop mass drug administration (MDA) and to establish post-MDA surveillance. Dominican Republic stopped MDA in all LF-endemic foci: La Ciénaga and Southwest passed the third Transmission Assessment Survey (TAS) and the Eastern focus passed TAS-1 in 2018. Haiti passed the TAS and interrupted transmission in >80% of endemic communes, achieving effective drug coverage. Guyana implemented effective coverage in MDAs in 2017 and 2018 and in 2019 scaled up the treatment for 100% of the geographical region, introducing ivermectin in the MDA in order to achieve LF elimination by the year 2026. The Americas region is on its way to eliminating LF transmission. However, efforts should be made to improve morbidity management to prevent disability of the already affected populations.

Systematic review of the effectiveness of selected drugs for preventive chemotherapy for Taenia solium taeniasis.

BACKGROUND: Preventive chemotherapy is a useful tool for the control of Taenia solium taeniasis and cysticercosis. The aim of this systematic review is to assess the scientific evidence concerning the effectiveness and safety of different drugs in preventive chemotherapy for T. solium taeniasis in endemic populations. METHODS: A systematic review was conducted of controlled and uncontrolled studies, assessing the efficacy and adverse effects (among other outcomes) of albendazole, niclosamide and/or praziquantel for preventive chemotherapy of T. solium taeniasis. A comprehensive search was conducted for published and unpublished studies. Two reviewers screened articles, completed the data extraction and assessment of risk of bias. A meta-analysis of cure rate and relative reduction in prevalence was performed. The protocol for this review was registered on the International prospective register of systematic reviews (PROSPERO), number CRD42018112533. RESULTS: We identified 3555 records, of which we included 20 primary studies reported across 33 articles. Meta-analyses of drug and dose showed that a single dose of praziquantel 10mg/kg, albendazole 400mg per day for three consecutive days, or niclosamide 2g, resulted in better cure rates for T. solium taeniasis (99.5%, 96.4% and 84.3%, respectively) than praziquantel 5mg/kg or single dose albendazole 400mg (89.0% and 52.0%, respectively). These findings have a low certainty of evidence due to high risk of bias in individual studies and heterogeneity in combined estimates. In relation to side-effects, most studies reported either no or only mild and transient side-effects within the first three days following drug administration for all drugs and doses. CONCLUSION: Evidence indicated that praziquantel 10mg/kg, niclosamide 2g, and triple dose albendazole 400mg were effective as taenicides and could be considered for use in mass drug administration programs for the control of T. solium taeniasis. Evidence was not found that any of these drugs caused severe side effects at the indicated doses, although the extent of the available evidence was limited.

Epidemiological situation of yaws in the Americas: A systematic review in the context of a regional elimination goal.

BACKGROUND: Yaws is targeted for eradication by 2020 in the WHA66.12 resolution of the World Health Assembly. The objective of this study was to describe the occurrence of yaws in the Americas and to contribute to the compilation of evidence based on published data to undertake the certification of yaws eradication. METHODOLOGY: A systematic review of the epidemiological situation of yaws in the Americas was performed by searching in MEDLINE, Embase, LILACS, SCOPUS, Web of Science, DARE and Cochrane Database of Systematic Reviews. Experts on the topic were consulted, and institutional WHO/PAHO library databases were reviewed. PRINCIPAL FINDINGS: Seventy-five full-text articles published between 1839 and 2012 met the inclusion criteria. Haiti and Jamaica were the two countries with the highest number of papers (14.7% and 12.0%, respectively). Three-quarters of the studies were conducted before 1970. Thirty-three countries reported yaws case count or prevalence data. The largest foci in the history were described in Brazil and Haiti. The most recent cases reported were recorded in eight countries: Suriname, Guyana, Colombia, Haiti, Martinique, Dominica, Trinidad and Tobago, and Brazil. Gaps in information and heterogeneity were detected in the methodologies used and outcome reporting, making cross-national and chronological comparisons difficult. CONCLUSIONS: The lack of recent yaws publications may reflect, in the best-case scenario, the interruption of yaws transmission. It should be possible to reach the eradication goal in the region of the Americas, but it is necessary to collect more information. We suggest updating the epidemiological status of yaws, especially in two countries that need to assess ongoing transmission. Twenty-four countries need to demonstrate the interruption of transmission and declare its status of yaws endemicity, and sixteen countries should declare if they are yaws-free. It is necessary to formally verify the achievement of this goal in Ecuador.

Polymorphism in the Plasmodium vivax msp 3: gene in field samples from Tierralta, Colombia.

We evaluated the Plasmodium vivax polymorphism by studying the Pvmsp-3alpha gene's polymorphic region by PCR-RFLP in 55 samples from patients living in Tierralta, Colombia. Three different sizes of the Pvmsp-3 alpha gene were found, type A (1,900 bp), type B (1,500 bp) and type C (1,100 bp); most of the samples were type A (96.4 %). The Pvmsp-3alpha gene exhibited high polymorphism. Seven restriction patterns were found when using Alu I, and nine were found with Hha I; 12 different alleles were obtained when these patterns were combined. The findings suggest that this gene could be used in Colombia as a molecular epidemiologic marker for genotyping P. vivax.

Asymptomatic Plasmodium spp. infection in Tierralta, Colombia.

With the aim of determining the prevalence of asymptomatic Plasmodium spp. infection by thick smear and PCR and its association with demographic and epidemiological characteristics in the village of Nuevo Tay, Tierralta, Córdoba, Colombia, a cross-sectional population study was carried out, using random probabilistic sampling. Venous blood samples were taken from 212 people on day 0 for thick smear and PCR. Clinical follow-up and thick smears were carried out on days 14 and 28. The prevalence of Plasmodium spp. infection was 17.9% (38/212; 95% CI: 12.5-23.3%) and the prevalence of asymptomatic Plasmodiumspp. infection was 14.6% (31/212; 95% CI: 9.6-19.6%). Plasmodium vivax was found more frequently (20/31; 64.5%) than Plasmodium falciparum (9/31; 29%) and mixed infections (2/31; 6.5%). A significantly higher prevalence of asymptomatic infection was found in men (19.30%) than in women (9.18%) (prevalence ratio: 2.10; 95% CI: 1.01-4.34%; p = 0.02). People who developed symptoms had a significantly higher parasitemia on day 0 than those who remained asymptomatic, of 1,881.5 +/- 3,759 versus 79 +/- 106.9 (p = 0.008). PCR detected 50% more infections than the thick smears. The presence of asymptomatic Plasmodium spp. infection highlights the importance of carrying out active searches amongst asymptomatic populations residing in endemic areas.

[Evaluation of TcH2AF-R and S35-S36 primers in PCR tests for the detection of Trypanosoma cruzi in mouse cardiac tissue]. / Evaluación de las pruebas de PCR TcH2AF-R y S35-S36 para la detección de Trypanosoma cruzi en tejido cardiaco de ratón.

INTRODUCTION: Heart transplant is a therapeutic option in the treatment of chagasic cardiomyopathy. For early detection of Chagas reactivation cases, the use of PCR tests using endomyocardial biopsies has been proposed. Development of an animal model will be the first step in evaluating the applicability of this approach. OBJECTIVE: PCR tests based on the TcH2AF-R and S35-S36 primers were evaluated for the detection of T. cruzi in heart tissue of mice experimentally infected with the parasite. MATERIALS AND METHODS: Two groups of ICR mice of 15 and 10 individuals were infected by intraperitoneal injection with 0.3 ml of PBS containing 1 x 10(6) trypomastigotes of the MHOM/CO/2001/D.A. (T. cruzi I) strain or 1 x 10(4) trypomastigotes of MHOM/BR/00/Y (T. cruzi II) strain. Parasitemia and cardiac parasitic infection were determined at 30, 60 (acute model), 100 and 150 (chronic model) days by means of histopathological examination and by PCR, using the TcH2AF-R and S35-S36 primers. RESULTS: The histopathological findings revealed alterations in the heart and the presence of intracellular amastigotes in acute and chronic models. In contrast to parasitemia levels and histopathological analyses, S35-S36 PCR detected infections in mice that were infected with either parasite strain. TcH2AF-R PCR detected T. cruzi I-infected mice earlier and more frequently than inspection for parasitemia or histopathological examination. CONCLUSIONS: Applying PCR tests with both primers proved superior for Chagas disease confirmation over currently standard detection methods.

[Efficacy of the amodiaquine+sulfadoxine-pyrimethamine combination and of chloroquine for the treatment of malaria in Córdoba, Colombia, 2006]. / Eficacia de la combinación amodiaquina más sulfadoxina-pirimetamina y de la cloroquina para el tratamiento del paludismo en Córdoba, Colombia, 2006.

INTRODUCTION: The decrease in the efficacy of antimalarial drugs in the world and in Colombia hampers its control. OBJECTIVE: The in vivo therapeutic efficacy of the amodiaquine+sulfadoxine-pyrimethamine combination was evaluated in the treatment of uncomplicated Plasmodium falciparum malaria and of chloroquine for P. vivax malaria. MATERIALS AND METHODS: From May to November 2006, in vivo efficacy studies of malaria treatments were undertaken in Tierralta, Córdoba, northeastern Colombia. Standard protocols were followed as recommended by the World Health Organization/Panamerican Health Organization, with some modifications. Patients older than two years with single P. falciparum or P. vivax infection, with asexual parasitemia between 500 and 50,000 parasites/microl, were selected according to established inclusion and exclusion criteria. Supervised treatment was administered, and clinical and parasitological follow-up was carried out on days 0 (inclusion), 1, 2, 3, 7, 14, 21 and 28. The outcome was defined as adequate clinical and parasitological response, early therapeutic failure, or late therapeutic failure. RESULTS: Of 53 subjects selected, 50 (94.3%; CI 70%-100%) presented adequate clinical and parasitological response to the amodiaquine+sulfadoxine-pyrimethamine treatment for uncomplicated falciparum malaria. One patient presented early therapeutic failure, and two developed late therapeutic failure. All of the 50 patients (95%CI: 74%-100%) in the invivo efficacy study of chloroquine for vivax malaria presented adequate clinical and parasitological response. CONCLUSION: In Cordoba, the amodiaquine+sulfadoxine-pyrimethamine combination and chloroquine show a high efficacy for the treatment of uncomplicated falciparum and vivax malaria, respectively.

Elimination of onchocerciasis from Colombia: first proof of concept of river blindness elimination in the world.

BACKGROUND: Onchocerciasis is a chronic parasitic infection originally endemic in 13 discrete regional foci distributed among six countries of Latin America (Brazil, Colombia, Ecuador, Guatemala, Mexico and Venezuela). In Colombia, this disease was discovered in 1965 in the Pacific Coast of the country. The National Onchocerciasis Elimination Program was established in 1993 with the aim of eliminating disease morbidity and infection transmission. In 2013, the World Health Organization (WHO) verified Colombia as free of onchocerciasis, becoming the first country in the world to reach such a goal. This report provides the empirical evidence of the elimination of Onchocerca volvulus transmission by Simulium exiguum (s.l.) after 12 years of 6-monthly mass drug administration of Mectizan® (ivermectin) to all the eligible residents living in this endemic area. METHODS: From 1996 onwards, a biannual community-based mass ivermectin administration programme was implemented, complemented by health education and community participation. In-depth parasitological, serological and entomological surveys were conducted periodically between 1998 and 2007 to evaluate the impact of ivermectin treatment according to the 2001 WHO guidelines. When the interruption of parasite transmission was demonstrated, the drug distribution ceased and a three-year post-treatment surveillance (PTS) period (2008-2010) was initiated. RESULTS: After 23 rounds of treatment, parasitological and ophthalmological assessments showed absence of microfilariae in skin and anterior chamber of the eyes. Serological tests proved lack of antibodies against O. volvulus in children under 10 years-old. A total of 10,500 S. exiguum flies tested by PCR had no L3 infection (infectivity rate = 0.0095%; 95% CI: 0.0029-0.049) during 2004, indicating interruption of parasite transmission. However, biannual ivermectin treatments continued until 2007 followed by a 3-year PTS period at the end of which 13,481 flies were analyzed and no infective flies were found (infectivity rate = 0%; 95% CI: 0.0-0.014). CONCLUSIONS: These results fulfilled the WHO criteria for onchocerciasis elimination. Consequently, in 2013 Colombia was verified as free of onchocerciasis, demonstrating that elimination of this neglected tropical disease is an achievable goal and paving the way for an elimination agenda to be followed by other endemic countries in Latin America and Africa.

Detection of Trypanosoma cruzi and Trypanosoma rangeli infection in triatomine vectors by amplification of the histone H2A/SIRE and the sno-RNA-C11 genes.

Trypanosoma rangeli is non pathogenic for humans but of important medical and epidemiological interest because it shares vertebrate hosts, insect vectors, reservoirs and geographic areas with T. cruzi, the etiological agent of Chagas disease. Therefore, in this work, we set up two PCR reactions, TcH2AF/R and TrFR2, to distinguish T. cruzi from T. rangeli in mixed infections of vectors based on amplification of the histone H2A/SIRE and the small nucleolar RNA Cl1 genes, respectively. Both PCRs were able to appropriately detect all T. cruzi or T. rangeli experimentally infected-triatomines, as well as the S35/S36 PCR which amplifies the variable region of minicircle kDNA of T. cruzi. In mixed infections, whereas T. cruzi DNA was amplified in 100% of samples with TcH2AF/R and S35/S36 PCRs, T. rangeli was detected in 71% with TrF/R2 and in 6% with S35/S36. In a group of Rhodnius colombiensis collected from Coyaima (Colombia), T. cruzi was identified in 100% with both PCRs and T. rangeli in 14% with TrF/R2 and 10% with S35/S36 PCR. These results show that TcH2AF/R and TrF/R2 PCRs which are capable of recognizing all T. cruzi and T. rangeli strains and lineages could be useful for diagnosis as well as for epidemiological field studies of T. cruzi and T. rangeli vector infections.

Genetic diversity of Giardia intestinalis populations in Colombia.

INTRODUCTION: Giardia intestinalis is a protozoan parasite that causes a gastrointestinal infection known as giardiosis, which is transmitted primarily through fecal-oral contamination. Genetic studies of axenically cultivated Giardia isolates have identified two major genetic groups distributed throughout the world. In the present study 24 native strains of the parasite were analyzed by the RAPD technique (Random Amplified Polymorphic DNA). OBJECTIVE: To determine the level of polymorphism and the complexity of Giardia intestinalis circulating strains in specific areas of Colombia. MATERIALS AND METHODS: The RAPD method was used, as it allows for a quick, simple and reliable analysis that requires no prior knowledge of the genetics of the parasite. A RAPD analysis was conducted on native isolates collected in Colombia between 1997 and 2001, established in continuous cultures. Several primers were tested separately, in order to enhance the capacity for discrimination of the method. RESULTS: Of the 24 strains that were included in the study, 22 were arranged in independent clusters. The strains that were from the same geographic area and collected at about the same time, generally displayed highly similar but distinguishable RAPD patterns. Clones isolated from a strain were analyzed as well, and it was possible to differentiate them molecularly. CONCLUSION: The studied strains showed to belong to genotype A . The results suggest that the Colombian strains studied consist of a heterogeneous mixture of closely related populations.

[Clinical profiles of patients with uncomplicated Plasmodum falciparum malaria in northwestern Colombia]. / Perfiles clínicos del paludismo no complicado por Plasmodium falciparum en Córdoba, Colombia.

INTRODUCTION: Few studies describe the clinical presentations of uncomplicated Plasmodium falciparum malaria in the province of Córdoba in an endemic area of northwestern Colombia. OBJECTIVE: Profiles of patients with uncomplicated Plasmodium falciparum malaria were described from two twons of Córdoba, Tierrata and Puerto Libertador, based on clinical, epidemiological and laboratory variables. MATERIALS AND METHODS: Patients were examined according to standard WHO/PAHO protocols for assessment of antimalarial drug efficacy. Clinical data and parasitological information was collected as well. A multiple correspondence multivariate analysis was used to compare the profiles of 127 patients with uncomplicated Plasmodium falciparum malaria. RESULTS: Of the 127 patients,105 completed the 14-day follow-up and 7 had adequate clinical response. Between 80% and 98% of patients exhibited at least one of the most frequent symptoms of uncomplicated malaria, and 80.3% had asthenia as the most frequent symptom. The multivariate analysis grouped the variables into five distinguishable clusters of clinical profiles. These groups showed similarities with the classical clinical descriptions of uncomplicated malaria encountered in the literature. The low frequency of patients with adequate clinical response hampered the association analysis. CONCLUSIONS: In Córdoba, therapeutic failure to chloroquine treatment is high in treating uncomplicated Plasmodium falciparum malaria. Multivariate analysis summarized variables related to epidemiological and clinical aspects and permitted a more objective approach to the interpretation of the findings.

[Acute Chagas disease in Colombia: a rarely suspected disease. Report of 10 cases presented during the 2002-2005 period]. / Enfermedad de Chagas aguda en Colombia, una entidad poco sospechada. Informe de 10 casos presentados en el periodo 2002 a 2005.

INTRODUCTION: In Colombia, reported cases of acute Chagas disease are sporadic. OBJECTIVE: Ten cases were described that had been reported to the Parasitology Laboratory of the Colombian National Health Institute between December 2002 and November 2005. MATERIALS AND METHODS: Information from clinical records, epidemiological report forms, laboratory and blood tests was collated. In addition the following data were compiled: demographic variables, clinical findings, results of laboratory tests and other exams (such as peripheral blood smears), IFAT for IgG antibodies, isolation in culture medium, inoculation in mice, polymerase chain reaction tests and isoenzyme eletrophoresis. RESULTS: All the cases presented in known endemic areas for Chagas disease transmission in Colombia. Three cases were from Putumayo Province, two each from the provinces of Arauca, Casanare, Norte de Santander and one from Santander Province. The probable mode of transmission was vector-borne. Seven cases presented in adults aged 18 to 50, three in children aged 6 months to 2 years. Seven were male and three were female. The most frequent symptom was fever in nine cases. Signs of portal of entry were rare; only one patient presented a possible Romahia's sign. Three patients presented myocarditis, two acute cardiac failure and one cardiac tamponade. Parasitemia was evident in nine cases; five had positive IgG serological tests; five cases were confirmed through parasite isolation; isoenzyme electrophoresis showed Trypanosoma cruzi group I. CONCLUSIONS: Clinical variability prevailed. In none of the cases was a clinical diagnosis suspected. The diagnosis was made and confirmed through laboratory tests alone. The results highlight the importance of including this disease in the differential diagnosis of febrile syndrome in endemic regions due to its good response to etiological treatment and thereby preventing its progression to the chronic phase.

Current status of the knowledge on the epidemiology of tungiasis in the Americas / Estado actual del conocimiento sobre las características epidemiológicas de la tungiasis en la Región de las Américas / Situação atual do conhecimento sobre a epidemiologia da tungíase nas Américas

ABSTRACT Objectives. To present the state-of-the-knowledge on the epidemiology of tungiasis in the Region of the Americas. Methods. A search of publications on the epidemiology of tungiasis in the Americas was performed in PubMed and LILACS databases from January 2007 to June 2021. In addition, a manual literature search on articles on the epidemiology of tungiasis was performed. Results. A total of 83 articles were analyzed which contained relevant information on tungiasis cases and their geographical distribution, prevalence and risk factors, life cycle, sites where transmission takes place, and zoonotic aspects. The on-host and off-host life cycles have been researched in detail. In certain contexts, the whole life cycle is completed indoors enabling transmission around the whole year. Cases were reported from 10 countries; 71% of them were from Brazil. In the general population, the prevalence varied between 1.0% and 82.6% according to the settings. Age-specific prevalence indicated that children and the elderly bear the highest disease burden. Risk factor studies indicate that tungiasis is associated with severe poverty. Conclusions. In the Americas, there are important gaps in information and knowledge of tungiasis. Understanding the burden, epidemiology, distribution, magnitude, related risk factors, and reservoirs, among others, is needed to develop and implement integrated control measures tailored to the context and patterns of transmission in the affected communities.

RESUMEN Objetivos. Presentar el estado del conocimiento sobre las características epidemiológicas de la tungiasis en la Región de las Américas. Métodos. Se hizo una búsqueda de publicaciones sobre las características epidemiológicas de la tungiasis en la Región en las bases de datos PubMed y LILACS en el período comprendido entre enero del 2007 y junio del 2021. Además, se realizó una búsqueda bibliográfica manual de artículos sobre las características epidemiológicas de la tungiasis. Resultados. Se analizaron en total 83 artículos que contenían información pertinente sobre casos de tungiasis y su distribución geográfica, prevalencia y factores de riesgo, ciclo de vida, lugares donde se produce la transmisión y aspectos zoonóticos. Se investigaron en detalle los ciclos de vida dentro y fuera del huésped. En ciertos contextos, la totalidad del ciclo de vida se completa en espacios cerrados, lo que permite la transmisión durante todo el año. Se notificaron casos en 10 países, con 71% de los casos notificados en Brasil. En la población general, la prevalencia varió entre 1,0% y 82,6% según el entorno. La prevalencia específica por edad indica que la población infantil y las personas mayores tienen la mayor carga de morbilidad. Los estudios relativos a los factores de riesgo indican que la tungiasis está relacionada con la pobreza extrema. Conclusiones. En la Región, hay lagunas importantes en la información y el conocimiento sobre la tungiasis. Es necesario comprender la carga, las características epidemiológicas, la distribución, la magnitud, los factores de riesgo relacionados y los reservorios, entre otros factores, para elaborar y aplicar medidas de control integradas adaptadas al contexto y los patrones de transmisión en las comunidades afectadas.

RESUMO Objetivos. Apresentar o estado do conhecimento sobre a epidemiologia da tungíase na Região das Américas. Métodos. Realizou-se uma pesquisa de estudos publicados de janeiro de 2007 a junho de 2021 sobre a epidemiologia da tungíase nas Américas nas bases de dados PubMed e LILACS, bem como uma pesquisa bibliográfica manual de artigos sobre a epidemiologia da tungíase. Resultados. Analisou-se um total de 83 artigos com informações de interesse sobre casos de tungíase e sua distribuição geográfica, prevalência e fatores de risco, ciclo vital, locais de transmissão e aspectos zoonóticos. Os ciclos vitais dentro e fora do hospedeiro foram pesquisados em detalhes. Em determinados contextos, todo o ciclo vital ocorre em ambientes fechados, o que possibilita a transmissão durante todo o ano. Relataram-se casos de 10 países; 71% deles no Brasil. Na população em geral, a prevalência variou de 1,0% a 82,6%, de acordo com o local. A prevalência específica por idade mostrou que a maior carga de doença ocorre em crianças e pessoas idosas. Estudos dos fatores de risco indicam que a tungíase está associada à extrema pobreza. Conclusões. Nas Américas, existem importantes lacunas de informação e conhecimento sobre a tungíase. É necessário compreender fatores como carga, epidemiologia, distribuição, magnitude, fatores de risco relacionados e reservatórios, entre outros, para desenvolver e implementar medidas integradas de controle adequadas ao contexto e aos padrões de transmissão nas comunidades afetadas.

Current status of the knowledge on the epidemiology of tungiasis in the Americas

[ABSTRACT]. Objectives. To present the state-of-the-knowledge on the epidemiology of tungiasis in the Region of the Americas. Methods. A search of publications on the epidemiology of tungiasis in the Americas was performed in PubMed and LILACS databases from January 2007 to June 2021. In addition, a manual literature search on articles on the epidemiology of tungiasis was performed. Results. A total of 83 articles were analyzed which contained relevant information on tungiasis cases and their geographical distribution, prevalence and risk factors, life cycle, sites where transmission takes place, and zoonotic aspects. The on-host and off-host life cycles have been researched in detail. In certain contexts, the whole life cycle is completed indoors enabling transmission around the whole year. Cases were reported from 10 countries; 71% of them were from Brazil. In the general population, the prevalence varied between 1.0% and 82.6% according to the settings. Age-specific prevalence indicated that children and the elderly bear the highest disease burden. Risk factor studies indicate that tungiasis is associated with severe poverty. Conclusions. In the Americas, there are important gaps in information and knowledge of tungiasis. Understanding the burden, epidemiology, distribution, magnitude, related risk factors, and reservoirs, among others, is needed to develop and implement integrated control measures tailored to the context and patterns of transmission in the affected communities.

[RESUMEN]. Objetivos. Presentar el estado del conocimiento sobre las características epidemiológicas de la tungiasis en la Región de las Américas. Métodos. Se hizo una búsqueda de publicaciones sobre las características epidemiológicas de la tungiasis en la Región en las bases de datos PubMed y LILACS en el período comprendido entre enero del 2007 y junio del 2021. Además, se realizó una búsqueda bibliográfica manual de artículos sobre las características epidemiológicas de la tungiasis. Resultados. Se analizaron en total 83 artículos que contenían información pertinente sobre casos de tungiasis y su distribución geográfica, prevalencia y factores de riesgo, ciclo de vida, lugares donde se produce la transmisión y aspectos zoonóticos. Se investigaron en detalle los ciclos de vida dentro y fuera del huésped. En ciertos contextos, la totalidad del ciclo de vida se completa en espacios cerrados, lo que permite la transmisión durante todo el año. Se notificaron casos en 10 países, con 71% de los casos notificados en Brasil. En la población general, la prevalencia varió entre 1,0% y 82,6% según el entorno. La prevalencia específica por edad indica que la población infantil y las personas mayores tienen la mayor carga de morbilidad. Los estudios relativos a los factores de riesgo indican que la tungiasis está relacionada con la pobreza extrema. Conclusiones. En la Región, hay lagunas importantes en la información y el conocimiento sobre la tungiasis. Es necesario comprender la carga, las características epidemiológicas, la distribución, la magnitud, los factores de riesgo relacionados y los reservorios, entre otros factores, para elaborar y aplicar medidas de control integradas adaptadas al contexto y los patrones de transmisión en las comunidades afectadas.

[RESUMO]. Objetivos. Apresentar o estado do conhecimento sobre a epidemiologia da tungíase na Região das Américas. Métodos. Realizou-se uma pesquisa de estudos publicados de janeiro de 2007 a junho de 2021 sobre a epidemiologia da tungíase nas Américas nas bases de dados PubMed e LILACS, bem como uma pesquisa bibliográfica manual de artigos sobre a epidemiologia da tungíase. Resultados. Analisou-se um total de 83 artigos com informações de interesse sobre casos de tungíase e sua distribuição geográfica, prevalência e fatores de risco, ciclo vital, locais de transmissão e aspectos zoonóticos. Os ciclos vitais dentro e fora do hospedeiro foram pesquisados em detalhes. Em determinados contextos, todo o ciclo vital ocorre em ambientes fechados, o que possibilita a transmissão durante todo o ano. Relataram-se casos de 10 países; 71% deles no Brasil. Na população em geral, a prevalência variou de 1,0% a 82,6%, de acordo com o local. A prevalência específica por idade mostrou que a maior carga de doença ocorre em crianças e pessoas idosas. Estudos dos fatores de risco indicam que a tungíase está associada à extrema pobreza. Conclusões. Nas Américas, existem importantes lacunas de informação e conhecimento sobre a tungíase. É necessário compreender fatores como carga, epidemiologia, distribuição, magnitude, fatores de risco relacionados e reservatórios, entre outros, para desenvolver e implementar medidas integradas de controle adequadas ao contexto e aos padrões de transmissão nas comunidades afetadas.

[Seroprevalence of canine visceral leishmaniasis in sector 8 of Neiva and in four municipalities of Huila, Colombia]. / Seroprevalencia de leishmaniosis visceral canina en la comuna 8 de Neiva y en cuatro municipios de Huila, Colombia.

INTRODUCTION: Canine visceral leishmaniasis in endemic areas of Colombia could be a public health risk factor given the zoonotic nature of the disease. Ninety-six human cases of visceral leishmaniasis were reported in Colombia in 2004, 5 of them in Huila, where Lutzomyia longipalpis has been incriminated as the main vector species. OBJECTIVE: To determine the prevalence of IgG antibodies against Leishmania chagasi in dogs from the sector 8 of the city of Neiva and the from the towns of Villavieja, Algeciras, Palermo and Rivera located in Huila, Colombia. MATERIALS AND METHODS: An epidemiological survey was carried out in 610 dogs, which included clinical examination and venopuncture for obtaining blood samples. Authorization was obtained from the dog owners. The sera were analyzed by the ELISA test with promastigotes of the L. chagasi strain MHOM/CO84/CLO44B as antigen. RESULTS: The canine population had an average age of 2.5 years; 67.3% of the dogs were males and the cross-bred animals were the most prevalent constituting 85% of those samples. On clinical examination the main signs were onicogriphosis 24.3%, lymphadenitis 10% and skin lesions 5%. The presence of antibodies was observed in 28.1% of the dogs from sector 8 of Neiva, 28% in Villavieja, 14.9% in Rivera, 10% in Palermo and 5.1% in Algeciras. An average ratio of five people cohabitating per seropositive dog was observed. CONCLUSIONS: The results reflect the exposure to Leishmania chagasi infection of dogs living in both urban and rural environments in the studied zones, and should encourage health authorities to carry out control measures to prevent the spread of this zoonotic disease.

[Genotyping of the Plasmodium falciparum msp1 (block 2) and dhfr (codon 108) genes in field samples collected in four endemic Colombian localities]. / Genotipificación de los genes msp1 (bloque 2) y dhfr (codón108) de Plasmodium falciparum en muestras de campo recolectadas en cuatro localidades endémicas de Colombia.

INTRODUCTION: Plasmodium falciparum is a highly polymorphic parasite, which allows it to evade the host's immune response, spread drug resistance and favours transmission. OBJECTIVES: To analyse the genetic diversity of P. falciparum populations in samples from four endemic localities in Colombia. MATERIALS AND METHODS: 123 blood samples were collected on filter paper from patients with non-complicated P. falciparum malaria during 2002 to 2004. The samples were genotyped using polymerase chain reaction with specific primers for the polymorphic region of block 2 of the msp1 gene and the 108 codon of the dhfr gene. RESULTS: In msp1 block 2, 95.9% (118/123; 95% CI: 90.8-98.7) of the samples harboured MAD20; 6.5% K1 (8/123; 95% CI: 2.8-12.4) and 2.4% RO33 (3/123; 95% CI: 0.5-6.9). For the dhfrgene the mutant allele N 108 was found in all the samples amplified, T 108 in 3.2% and the wild type S108 in 34.1%. Taking together all the results from both genes, 61.8% (76/123; 95% CI: 52.6-70.4) of the samples were simple infections and 38.2% (47/123; 95% CI: 29.6-47.4) were mixed infections. MAD20/N108-S108 (30.1%) was the most frequent combination among the latter. CONCLUSIONS: Simple infections, i.e, a single allelic type in each one of the genes studied, prevailed among the circulating parasite populations. In this study the genetic composition of P. falciparum parasite populations was very homogeneous.