Engels Banegas’s research while affiliated with Secretaría de Salud and other places

Background As Malaria cases are continuously reported across the globe, epidemiological and integral approaches should be considered for an optimal stratification on endemic areas for elimination goal. In Central America, a 75% reduction in malaria incidence has been reported between 2000 and 2015, similarly, in Honduras, more than 75% of total cases in 2016 were concentrated in 7 municipalities, mainly in Gracias Dios department. Achieve malaria elimination in Honduras demands the implementation of strategies to identify main hotspots. Methods Based on WHO guidelines, local malaria epidemiological data from case-based surveillance system of the Ministry of Health between January and December 2016 were analysed. Furthermore, on field evaluations were carried out in Puerto Lempira municipality, Gracias a Dios department to an analysis validation. Finally, a set of epidemiological components were generated and proposed together with risk-factor description and proposed actions for health system improvement. Results On 2016, Gracias a Dios reported 61% of total malaria cases in Honduras; based on our analysis, 12 micro-areas were identified, including epidemiological, entomological, and socio-demographic information from local technicians. Conclusions Malaria elimination in endemic areas urges implementation of different strategies, here we show the on-field micro-stratification process of 12 “micro-areas” carried out in one endemic department of Honduras. This information provides a more targeted strategy for diagnosis, treatment, and vector control interventions for malaria elimination goal in Honduras.

Background: The incidence of malaria in the Americas has decreased markedly in recent years. Honduras and the other countries of Mesoamerica and the island of Hispaniola have set the goal of eliminating native malaria by the year 2020. To achieve this goal, Honduras has recently approved national regulations to expand the possibilities of a shortened double dose primaquine (PQ) treatment for vivax malaria. Considering this new shortened anti-malarial treatment, the high frequency of G6PDd genotypes in Honduras, and the lack of routinely assessment of the G6PD deficiency status, this study aimed at investigating the potential association between the intake of PQ and haemolysis in malaria-infected G6PDd subjects. Methods: This was a prospective cohort and open-label study. Participants with malaria were recruited. Plasmodium vivax infection was treated with 0.25 mg/kg of PQ daily for 14 days. Safety and signs of haemolysis were evaluated by clinical criteria and laboratory values before and during the 3rd and 7th day of PQ treatment. G6PD status was assessed by a rapid test (CareStart ™) and two molecular approaches. Results: Overall 55 participants were enrolled. The frequency of G6PD deficient genotypes was 7/55 (12.7%), where 5/7 (71.4%) were hemizygous A− males and 2/7 (28.6%) heterozygous A− females. Haemoglobin concentrations were compared between G6PD wild type (B) and G6PDd A− subjects, showing a significant difference between the means of both groups in the 3rd and 7th days. Furthermore, a statistically significant difference was evident in the change in haemoglobin concentration between the 3rd day and the 1st day for both genotypes, but there was no statistical difference for the change in haemoglobin concentration between the 7th day and the 1st day. Besides these changes in the haemoglobin concentrations, none of the patients showed signs or symptoms associated with severe haemolysis, and none needed to be admitted to a hospital for further medical attention. Conclusions: The findings support that the intake of PQ during 14 days of treatment against vivax malaria is safe in patients with a class III variant of G6PDd. In view of the new national regulations in the shortened treatment of vivax malaria for 7 days, it is advisable to be alert of potential cases of severe haemolysis that could occur among G6PD deficient hemizygous males with a class II mutation such as the Santamaria variant, previously reported in the country.

Background Malaria remains a public health problem in some countries of Central America. Rapid diagnostic tests (RDTs) are one of the most useful tools to assist in the diagnosis of malaria in remote areas. Since its introduction, a wide variety of RDTs have been developed for the detection of different parasite antigens. PfHRP2 is the most targeted antigen for the detection of Plasmodium falciparum infections. Genetic mutations and gene deletions are important factors influencing or affecting the performance of rapid diagnostic tests. Methods In order to demonstrate the presence or absence of the pfhrp2 and pfhrp3 genes and their flanking regions, a total of 128 blood samples from patients with P. falciparum infection from three Central American countries were analysed through nested or semi-nested PCR approaches. ResultsIn total, 25.8 and 91.4% of the isolates lacked the region located between exon 1 and exon 2 of pfhrp2 and pfhrp3 genes, respectively. Parasites from the three countries showed deletions of one or both genes. The highest proportion of pfhrp2 deletions was found in Nicaragua while the isolates from Guatemala revealed the lowest number of pfhrp2 deletions. Parasites collected from Honduras showed the highest proportion of phfrp3 absence (96.2%). Twenty-one percent of isolates were double negative mutants for the exon 1–2 segment of both genes, and 6.3% of isolates lacked the full-length coding region of both genes. Conclusions This study provides molecular evidence of the existence of P. falciparum isolates lacking the pfhrp2 and pfhrp3 genes, and their flanking regions, in Honduras, Guatemala and Nicaragua. This finding could hinder progress in the control and elimination of malaria in Central America. Continuous evaluation of RDTs and molecular surveillance would be recommended.

Elimination of malaria in over 35 countries is a goal for 2030 in the Global Technical Strategy 2015-2030. With this vision, an updated “Framework for Malaria Elimination” has been published by World Health Organization (WHO). Honduras, part of the Regional Initiative for “Elimination of Malaria in Mesoamerica and Island of Hispaniola”, aims to eliminate malaria by the year 2020. National Malaria Strategic Plans 2012-2015 and 2014-2017 of Honduras were based on stratification of municipalities in high, medium and low risk based on annual parasite incidence (API) of one year, and in strata 1-3 based on API of last three years respectively. Epidemiological information by plausible place of infection from the country’s case based surveillance system was used. Access to diagnosis and treatment through microscopy posts and community collaborators using RDTs was mapped. Vulnerability was mapped using patterns of movement between communities and their intensity using local knowledge. Other information like vector behaviour and distribution, KAP studies and local contextual information were also used. Local factors considered as drivers of transmission, deficiencies in the health systems coverage were identified and response strategy unique for each area was formulated. This was done in March of 2017 for stratification as part of National Strategic Planning for 2018-2022 period. Gracias a Dios, the state with most malaria in the country, was stratified in to twelve micro-areas. These range from one community to over 31 communities, spanning six municipalities and cutting across administrative boundaries. Each micro-area has a distinct local epidemiology varying from 0-2 cases annually per community to 0-33 cases in others, with 0 cases due to P. falciparum to 53% of total cases annually (779), a population of 895 people to over 9000, and from isolated to being located on common trading routes with high migration. Overall the country was stratified in 16 major micro-areas of transmission. This micro-stratification approach put into practice the tenets of the WHO malaria elimination framework. It identified problems and necessary solutions at the local level, vital for elimination planning. This micro-stratification process will guide similar planning exercise to be conducted at in Honduras and in other countries of the Americas.

Background Recent studies have demonstrated the deletion of the histidine-rich protein 2 (PfHRP2) gene (pfhrp2) in field isolates of Plasmodium falciparum, which could result in false negative test results when PfHRP2-based rapid diagnostic tests (RDTs) are used for malaria diagnosis. Although primary diagnosis of malaria in Honduras is determined based on microscopy, RDTs may be useful in remote areas. In this study, it was investigated whether there are deletions of the pfhrp2, pfhrp3 and their respective flanking genes in 68 P. falciparum parasite isolates collected from the city of Puerto Lempira, Honduras. In addition, further investigation considered the possible correlation between parasite population structure and the distribution of these gene deletions by genotyping seven neutral microsatellites.Methods Sixty-eight samples used in this study, which were obtained from a previous chloroquine efficacy study, were utilized in the analysis. All samples were genotyped for pfhrp2, pfhrp3 and flanking genes by PCR. The samples were then genotyped for seven neutral microsatellites in order to determine the parasite population structure in Puerto Lempira at the time of sample collection.ResultsIt was found that all samples were positive for pfhrp2 and its flanking genes on chromosome 8. However, only 50% of the samples were positive for pfhrp3 and its neighboring genes while the rest were either pfhrp3-negative only or had deleted a combination of pfhrp3 and its neighbouring genes on chromosome 13. Population structure analysis predicted that there are at least two distinct parasite population clusters in this sample population. It was also determined that a greater proportion of parasites with pfhrp3-(and flanking gene) deletions belonged to one cluster compared to the other.Conclusion The findings indicate that the P. falciparum parasite population in the municipality of Puerto Lempira maintains the pfhrp2 gene and that PfHRP2-based RDTs could be considered for use in this region; however continued monitoring of parasite population will be useful to detect any parasites with deletions of pfhrp2.

Countries could use the monitoring of drug resistance in malaria parasites as an effective early warning system to develop the timely response mechanisms that are required to avert the further spread of malaria. Drug resistance surveillance is essential in areas where no drug resistance has been reported, especially if neighbouring countries have previously reported resistance. Here, we present the results of a four-year surveillance program based on the sequencing of the pfcrt gene of Plasmodium falciparum populations from endemic areas of Honduras. All isolates were susceptible to chloroquine, as revealed by the pfcrt “CVMNK” genotype in codons 72-76.

Background: Although LLINs are effective up to 3 to 5 years, a major limiting factor to its prolonged use is the physical durability of the LLIN which depends on a number of human and cultural factors. No data is available for physical durability of LLINs in field conditions in Central American countries which this study explores. Methods: LLINs were directly installed with planned coverage of all sleeping places in all homes of all localities of the municipality Wampusirpi, Honduras in 2010. On completion of one year of the LLIN installation campaign, a representative sample population from three localities of the municipality were selected for evaluation. Results: Of the 282 homes included in the final analysis, 92.91% (95% CI 89.91-95.90) had one or more LLINs in 2011. Although a majority (65.05%, 59.48-70.61) of the bednets had no holes or had holes of one finger breadth (9.48%, 6.06-12.90), 25.36% (20.28-30.44) were either lost, completely destroyed or with holes of more than 5 finger width and thus required replacement. Conclusion: The high proportion of LLINs requiring replacement increases the number of LLINs needed for maintaining an optimum coverage.

Background Understanding the population structure of Plasmodium species through genetic diversity studies can assist in the design of more effective malaria control strategies, particularly in vaccine development. Central America is an area where malaria is a public health problem, but little is known about the genetic diversity of the parasite’s circulating species. This study aimed to investigate the allelic frequency and molecular diversity of five surface antigens in field isolates from Honduras. Methods Five molecular markers were analysed to determine the genotypes of Plasmodium vivax and Plasmodium falciparum from endemic areas in Honduras. Genetic diversity of ama-1, msp-1 and csp was investigated for P. vivax, and msp-1 and msp-2 for P. falciparum. Allelic frequencies were calculated and sequence analysis performed. Results and conclusion A high genetic diversity was observed within Plasmodium isolates from Honduras. A different number of genotypes were elucidated: 41 (n = 77) for pvama-1; 23 (n = 84) for pvcsp; and 23 (n = 35) for pfmsp-1. Pvcsp sequences showed VK210 as the only subtype present in Honduran isolates. Pvmsp-1 (F2) was the most polymorphic marker for P. vivax isolates while pvama-1 was least variable. All three allelic families described for pfmsp-1 (n = 30) block 2 (K1, MAD20, and RO33), and both allelic families described for the central domain of pfmsp-2 (n = 11) (3D7 and FC27) were detected. However, K1 and 3D7 allelic families were predominant. All markers were randomly distributed across the country and no geographic correlation was found. To date, this is the most complete report on molecular characterization of P. vivax and P. falciparum field isolates in Honduras with regards to genetic diversity. These results indicate that P. vivax and P. falciparum parasite populations are highly diverse in Honduras despite the low level of transmission.

Background: Access to diagnosis and appropriate and timely treatment is one of the components of the global strategy for malaria control. External evaluation is necessary for standardizing microscopy processes across countries and improving the quality of diagnosis. Methodology: National laboratories of Honduras and Peru were selected as reference laboratories, and prepared panels to be sent to participating countries. Panels were sent to countries that entered the results in a virtual reporting system –NETLAB, within 10 working days of receipt of the panel. Results: Of the 23 national laboratories invited, 12 participated in the evaluation process in 2011. Of these, 70% of the laboratories had an acceptable degree of diagnostic agreement, 8% (1/12) were consistent in identifying parasite species and 16.6% (2/12) identified the sexual stages correctly. None of the laboratories evaluated were consistent in measuring parasitemia. Conclusions: These results have shown that the microscopic diagnosis of malaria in the countries of the Americas is deficient and needs improvement. The evaluation will serve in standardization of processes and protocols across countries in microscopic diagnosis of malaria.