Plasmodium vivax MSP1-42 kD Variant Proteins Detected Naturally Induced IgG Antibodies in Patients Regardless of the Infecting Parasite Phenotype in Mesoamerica.

BACKGROUND: The serological tests using blood stage antigens might be helpful for detecting recent exposure to Plasmodium parasites, and seroepidemiological studies would aid in the elimination of malaria. This work produced recombinant proteins of PvMSP142 variants and evaluated their capacity to detect IgG antibodies in symptomatic patients from Mesoamerica. METHODS: Three variant Pvmsp142 genes were cloned in the pHL-sec plasmid, expressed in the Expi293F™ eukaryotic system, and the recombinant proteins were purified by affinity chromatography. Using an ELISA, 174 plasma or eluted samples from patients infected with different P. vivax haplotypes were evaluated against PvMSP142 proteins and to a native blood stage antigen (NBSA). RESULTS: The antibody IgG OD values toward PvMSP142 variants (v88, v21, and v274) were heterogeneous (n = 178; median = 0.84 IQR 0.28-1.64). The correlation of IgG levels among all proteins was very high (spearman's rho = 0.96-0.98; p < 0.0001), but was lower between them and the NBSA (rho = 0.771; p < 0.0001). In only a few samples, higher reactivity to the homologous protein was evident. Patients with a past infection who were seropositive had higher IgG levels and lower parasitemia levels than those who did not (p < 0.0001). CONCLUSIONS: The PvMSP142 variants were similarly efficient in detecting specific IgG antibodies in P. vivax patients from Mesoamerica, regardless of the infecting parasite's haplotype, and might be good candidates for malaria surveillance and epidemiological studies in the region.

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.

Assessment of Plasmodium falciparum anti-malarial drug resistance markers in pfcrt and pfmdr1 genes in isolates from Honduras and Nicaragua, 2018-2021.

BACKGROUND: Central America and the island of Hispaniola have set out to eliminate malaria by 2030. However, since 2014 a notable upturn in the number of cases has been reported in the Mosquitia region shared by Nicaragua and Honduras. In addition, the proportion of Plasmodium falciparum malaria cases has increased significantly relative to vivax malaria. Chloroquine continues to be the first-line drug to treat uncomplicated malaria in the region. The objective of this study was to evaluate the emergence of chloroquine resistant strains of P. falciparum using a genetic approach. Plasmodium vivax populations are not analysed in this study. METHODS: 205 blood samples from patients infected with P. falciparum between 2018 and 2021 were analysed. The pfcrt gene fragment encompassing codons 72-76 was analysed. Likewise, three fragments of the pfmdr1 gene were analysed in 51 samples by nested PCR and sequencing. RESULTS: All samples revealed the CVMNK wild phenotype for the pfcrt gene and the N86, Y184F, S1034C, N1042D, D1246 phenotype for the pfmdr1 gene. CONCLUSIONS: The increase in falciparum malaria cases in Nicaragua and Honduras cannot be attributed to the emergence of chloroquine-resistant mutants. Other possibilities should be investigated further. This is the first study to report the genotype of pfmdr1 for five loci of interest in Central America.

Evidence of a Recent Bottleneck in Plasmodium falciparum Populations on the Honduran-Nicaraguan Border.

The countries of Central America and the island of Hispaniola have set the goal of eliminating malaria in less than a decade. Although efforts to reduce the malaria burden in the region have been successful, there has been an alarming increase in cases in the Nicaraguan Moskitia since 2014. The continuous decrease in cases between 2000 and 2014, followed by a rapid expansion from 2015 to the present, has generated a potential bottleneck effect in the populations of Plasmodium spp. Consequently, this study aimed to evaluate the genetic diversity of P. falciparum and the decrease in allelic richness in this population. The polymorphic regions of the pfmsp-1 and pfmsp-2 genes of patients with falciparum malaria from Honduras and Nicaragua were analyzed using nested PCR and sequencing. Most of the samples were classified into the K1 allelic subfamily of the pfmsp-1 gene and into the 3D7 subfamily of the pfmsp-2 gene. Despite the low genetic diversity found, more than half of the samples presented a polyclonal K1/RO33 haplotype. No sequence polymorphisms were found within each allelic subfamily. This study describes a notable decrease in the genetic diversity of P. falciparum in the Moskitia region after a bottleneck phenomenon. These results will be useful for future epidemiological investigations and the monitoring of malaria transmission in Central America.

Molecular variation of Plasmodium vivax dehydrofolate reductase in Mexico and Nicaragua contrasts with that occurring in South America / Variación molecular de la dehidrofolato reductasa de Plasmodium vivax en México y Nicaragua contrasta con la que ocurre en Sudamérica

Abstract: Objective: To research mutations associated to pyrimethamine resistance in dihydrofolate reductase (pvdhfr) of Plasmodium vivax from Mexico and Nicaragua and compare it to that reported in the rest of America. Materials and methods: Genomic DNA was obtained from P. vivax-infected blood samples. A pvdhfr gene fragment was amplified and sequenced. The identified gene variations were compared to those observed in other affected sites of America. Results: No mutations in pvdhfr were detected in P. vivax from Mexico and Nicaragua. One synonymous change and variation in the repeat domain was detected in Nicaraguan parasites. In South America, a high frequency of variant residues 58R and 117N associated to pyrimethamine resistance was reported. Conclusions: The lack of polymorphisms associated with pyrimethamine resistance suggests that drug-resistant P. vivax has not penetrated Mesoamerica, nor have local parasites been under selective pressure. These data contribute to establish the basis for the epidemiological surveillance of drug resistance.

Resumen: Objetivo: Determinar mutaciones en la dihydrofolato reductasa deP. vivax (Pvdhfr) en parásitos de México y Nicaragua, y comparar con lo reportado en América. Material y métodos: Del ADN de sangres infectadas con P. vivax de pacientes, el gen pvdhfr se amplifico y secuenció, y se contrastócon lo observado en América. Resultados: No se detectaron mutaciones asociadas con la resistencia debida a pirimetamina. Los parásitos de Nicaragua tuvieron una mutación sinónima y variación en la región repetida. Se reportaron frecuentes mutaciones asociadas con la resistencia a la pirimetamina en Sudamérica. Conclusiones: La ausencia de polimorfismos en Pvdhfr sugiere que no se han seleccionado ni introducido parásitos resistentes en la zona de estudio, lo que resulta muy útil para la vigilancia epidemiológica.

Molecular variation of Plasmodium vivax dehydrofolate reductase in Mexico and Nicaragua contrasts with that occurring in South America.

OBJECTIVE: To research mutations associated to pyrimethamine resistance in dihydrofolate reductase (pvdhfr) of Plasmodium vivax from Mexico and Nicaragua and compare it to that reported in the rest of America. MATERIALS AND METHODS: Genomic DNA was obtained from P. vivax-infected blood samples. A pvdhfr gene fragment was amplified and sequenced. The identified gene variations were compared to those observed in other affected sites of America. RESULTS: No mutations in pvdhfr were detected in P. vivax from Mexico and Nicaragua. One synonymous change and variation in the repeat domain was detected in Nicaraguan parasites. In South America, a high frequency of variant residues 58R and 117N associated to pyrimethamine resistance was reported. CONCLUSIONS: The lack of polymorphisms associated with pyrimethamine resistance suggests that drug-resistant P. vivax has not penetrated Mesoamerica, nor have local parasites been under selective pressure. These data contribute to establish the basis for the epidemiological surveillance of drug resistance.

OBJETIVO: Determinar mutaciones en la dihydrofolato reductasa de P. vivax (Pvdhfr) en parásitos de México y Nicaragua, y comparar con lo reportado en América. MATERIAL Y MÉTODOS: Del ADN de sangres infectadas con P. vivax de pacientes, el gen pvdhfr se amplifico y secuenció, y se contrastócon lo observado en América. RESULTADOS: No se detectaron mutaciones asociadas con la resistencia debida a pirimetamina. Los parásitos de Nicaragua tuvieron una mutación sinónima y variación en la región repetida. Se reportaron frecuentes mutaciones asociadas con la resistencia a la pirimetamina en Sudamérica. CONCLUSIONES: La ausencia de polimorfismos en Pvdhfr sugiere que no se han seleccionado ni introducido parásitos resistentes en la zona de estudio, lo que resulta muy útil para la vigilancia epidemiológica.

Genetic diversity and natural selection of Plasmodium vivax multi-drug resistant gene (pvmdr1) in Mesoamerica.

BACKGROUND: The Plasmodium vivax multidrug resistant 1 gene (pvmdr1) codes for a transmembrane protein of the parasite's digestive vacuole. It is likely that the pvmdr1 gene mutations occur at different sites by convergent evolution. In here, the genetic variation of pvmdr1 at three sites of the Mesoamerican region was studied. Since 1950s, malarious patients of those areas have been treated only with chloroquine and primaquine. METHODS: Blood samples from patients infected with P. vivax were obtained in southern Mexico (SMX), in the Northwest (NIC-NW) and in the northeast (NIC-NE) of Nicaragua. Genomic DNA was obtained and fragments of pvmdr1 were amplified and sequenced. The nucleotide and amino acid changes as well as the haplotype frequency in pvmdr1 were determined per strain and per geographic site. The sequences of pvmdr1 obtained from the studied regions were compared with homologous sequences from the GenBank database to explore the P. vivax genetic structure. RESULTS: In 141 parasites, eight nucleotide changes (two changes were synonymous and other six were nonsynonymous) were detected in 1536 bp. The PvMDR1 amino acid changes Y976F, F1076FL were predominant in endemic parasites from NIC-NE and outbreak parasites in NIC-NW but absent in SMX. Thirteen haplotypes were resolved, and found to be closely related, but their frequency at each geographic site was different (P = 0.0001). The pvmdr1 codons 925-1083 gene fragment showed higher genetic and haplotype diversity in parasites from NIC-NE than the other areas outside Latin America. The haplotype networks suggested local diversification of pvmdr1 and no significant departure from neutrality. The F ST values were low to moderate regionally, but high between NIC-NE or NIC-NW and other regions inside and outside Latin America. CONCLUSIONS: The pvmdr1 gene might have diversified recently at regional level. In the absence of significant natural, genetic drift might have caused differential pvmdr1 haplotype frequencies at different geographic sites in Mesoamerica. A very recent expansion of divergent pvmdr1 haplotypes in NIC-NE/NIC-NW produced high differentiation between these and parasites from other sites including SMX. These data are useful to set a baseline for epidemiological surveillance.

Genetic structure of Plasmodium vivax in Nicaragua, a country in the control phase, based on the carboxyl terminal region of the merozoite surface protein-1.

Malaria is still a grave public health problem in tropical areas of the world. The greater genetic diversity of Plasmodium vivax at geographic sites with less control over infection evidences the importance of genetic studies of these parasites. The present genetic study compares P. vivax in Nicaragua, which is still in the control phase, with this species in several other countries. In Nicaragua, P. vivax causes over 80% of malaria cases, most occurring in two remote northern regions. Plasmodium asexual blood-stage antigens, implicated in reticulocyte invasion, are possible molecular markers for analyzing parasite population genetics and for developing vaccines. The aim of this work was to investigate the genetic structure of P. vivax based on the 42kDa merozoite surface protein-1 (PvMSP-142), which may represent a sensitive marker for evaluating malaria transmission control. From blood samples of patients with P. vivax, we amplified PvMSP-142, obtained the nucleotide sequences, and compared them to homologous sequences of parasites from other geographic sites, retrieved from the GenBank. The 92 nucleotide sequences of P. vivax resulted in the resolution of eight haplotypes, six exclusive to Nicaragua. The great nucleotide diversity (π=0.020), the minimal recombination events (Rm=11), and the dN-dS values were similar to other control phase countries. FST values between parasites were low (0.069) for Nicaragua versus Brazil but higher for Nicaragua versus other regions (0.134-0.482). The haplotype network revealed five lineages: two were very frequent in Nicaragua and closely related to American parasites; three have been detected in multiple geographic sites around the world. These results suggest that P. vivax in Nicaragua is a differentiated and genetically diverse population (mainly due to mutation, positive balancing selection and recombination) and that PvMSP-142 may be a sensitive marker for evaluating sustained reduction in malaria transmission and for developing vaccines.

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.

Validation of a rapid and reliable test for diagnosis of chagas' disease by detection of Trypanosoma cruzi-specific antibodies in blood of donors and patients in Central America.

In this study we compared the performance of the Chagas Stat-Pak rapid immunochromatographic test with a standard enzyme-linked immunosorbent assay (ELISA) in the serodiagnosis of Chagas' disease in Central America. Out of 3,400 blood donor samples, 156 (4.6%) were positive in both assays. Three sera out of 2,084 samples from reference laboratories were negative with the rapid test but positive with the ELISA (99.8% agreement). Agreement of 100% between the two tests was observed with 339 additional sera from patients with cardiopathies and 175 sera from potential blood donors in emergency surgical cases occurring on weekends or at night. In conclusion, Chagas Stat-Pak showed 99.6% and 99.9% sensitivity and specificity, respectively, when assayed with 5,998 serum samples. It is a sensitive and specific alternative to the ELISA, as required in medical emergencies and blood screenings in Central America.

Manual de procedimientos para el control de la enfermedad de chagas / Manual of procedures pra the control of the chagas illness

Presenta Manual de Procedimientos para el Control de la enfermedad de Chagas, el cual es el resultado de una revisión bibliográfica exhaustiva sobre el tema y parte de un proceso de consulta y encuentros técnicos surgidos ante la necesidad imperiosa de estandarizar metodologías, que permitan unificar cirterios y aplicar los conocimientos adquiridos en el control de ésta parasitosis, en aras de mejorar el abordaje, manejo, seguimiento clínico y de laboratorio de los pacientes chagásicos e implementar paralelamente acciones de control vectorial acertadas en las áreas de mayor riesgo de transmisión. El principal propósito de este Manual, es servir de guía y material de consulta diaria al personal médico, paramédico y técnico que labora en las distintas unidades de salud endémicas del país, lo que sin lugar a dudas redundará a corto y mediano plazo en una mejor calidad de la atención que actualmente brindan los servicios de salud pública a los pacientes diagnosticados con enfermedad de chagas

Manual de procedimientos para el control de la enfermedad de chagas / Manual of procedures pra the control of the chagas illness

Presenta Manual de Procedimientos para el Control de la enfermedad de Chagas, el cual es el resultado de una revisión bibliográfica exhaustiva sobre el tema y parte de un proceso de consulta y encuentros técnicos surgidos ante la necesidad imperiosa de estandarizar metodologías, que permitan unificar criterios y aplicar los conocimientos adquiridos en el control de ésta parasitosis, en aras de mejorar el abordaje, manejo, seguimiento clínico y de laboratorio de los pacientes chagásicos e implementar paralelamente acciones de control vectorial acertadas en las  areas de mayor riesgo de transmisión. El principal propósito de este Manual, es servir de guía y material de consulta diaria al personal médico, paramédico y técnico que labora en las distintas unidades de salud endémicas del país, lo que sin lugar a dudas redundar  a corto y mediano plazo en una mejor calidad de la atención que actualmente brindan los servicios de salud pública a los pacientes diagnosticados con enfermedad de chagas...

Frequencies of feline blood types in northern Portugal.

The frequencies of feline blood types in northern Portugal were studied by surveying 185 pedigreed and nonpedigreed cats. Blood typing was performed by the traditional tube method. As a single group, the majority of cats were type A (90.3%), 3.8% were type B, and 5.9% were type AB. Among pedigreed cats, 19 were Siamese and 7 were Persian; all but 1 were type A. Among nonpedigreed cats, 89.3% were type A, 4.4% were type B, and 6.3% were type AB.

Antigenic diversity in maxadilan, a salivary protein from the sand fly vector of American visceral leishmaniasis.

The salivary protein maxadilan (MAX) is a vasodilator and immunomodulator from the sand fly vector of the protozoan parasite Leishmania chagasi. Vaccinating BALB/c mice with sand fly salivary gland extracts or with MAX protects the host against L. major infection. Because of the potential use of MAX in an anti-Leishmania vaccine, we characterized the vertebrate host IgG response to MAX in the present study. Our immunochemical analysis indicated that antibodies to MAX were detected in BALB/c mice, as well as in pigs and humans, from a area in Nicaragua endemic for Lutzomyia longipalpis. Previous studies demonstrate that the MAX protein is polymorphic on the amino acid level. Our findings suggested that naturally occurring MAX variants were recognized specifically by the host immune system and antigenicity appeared to be associated with amino-acid sequence variability. Thus, antigenic diversity of MAX and possibly of other arthropod salivary proteins may dictate the development of vector-based vaccines(s).

[Combined fixed doses therapy in systemic hypertension]. / Tratamiento combinado con dosis fijas de la hipertensión arterial.

OBJECTIVE: A single blind clinical trial was conducted to assess the concept that initial treatment in stage I and II of hypertension with fixed doses of two antihypertensives that have different modes of action and additive effects, in a 24-week period with bisoprolol (B), an cardioselective beta blocker, that does not have intrinsic sympathomimetic activity, associated to hydrochlorothiazide (HCTZ). MATERIAL AND METHODS: Thirty-one patients (22 females and 9 male) were included, with an age range between 20 and to 70 years (mean 52.45 +/- 12.10). After a two-weeks wash out period and a similar placebo phase, patients were assigned to receive a once-daily dosing of B 5 mg and 6.25 mg of HCTZ, during eight-weeks. Those patients that did not reduce their blood pressure below 90 mm Hg received a double dose of the beta blocker until the end of the study. RESULTS: After twenty-fourth weeks period of the study, the mean systolic/diastolic blood pressures reduction was 23.9/20.1 mm Hg, compared to basal levels (p < 0.001). The adverse effects were rare. No clinically significant changes from baseline in laboratory parameters were observed. CONCLUSION: This study demonstrates that fixed doses combination therapy with B/HCTZ (5 mg plus 6.25 mg) is effective and well tolerated, with a sustained hypotensive effect. Combined therapy with fixed doses, is an alternative in the initial treatment of mild to moderate hypertension.

Estudio comparativo entre bisoprolol y metoprolol, asociados a hidroclorotiazida, como terapia antihipertensiva / Comparative study between bisoprolol and metoprolol/hydrochlorothiazide in anti-hypertensive therapy

El objetivo de este estudio fue el de comparar la eficacia y seguridad del bisoprolol (B), un nuevo betabloqueador cardioselectivo (desprovisto de actividad simpaticomimético intrínseca) y del metoprolol (M) asociados a hidroclorotiazida (HCTZ) en el tratamiento de la hipertensión arterial (HTA) leve a moderada. En un estudio doble ciego, aleatorizado, controlado con placebo fueron evaluados 62 pacientes (47 mujeres y 15 hombres), con edades entre 20 y 70 años (media 52.5 ñ 10.4). Después de un periodo de lavado y una fase de placebo de 2 semanas cada uno, los enfermos fueron asignados recibir B (10 mg) más 6.25 mg de HCTZ o M (100 mg) más 6.25 mg de HCTZ, durante 4 semanas. Al término de este periodo, aquellos enfermos en los cuales no se había reducido la presión arterial diastólica (PAD) por abajo de 90 mmHg la dosis del betabloqueador fue duplicada. Después de ocho semanas de tratamiento, la disminución promedio en la presión arterial sistólica (PAS) y PAD en relación a los valores basales fueron: 31.8 mmHg/21.2 mmHg y 28.0 mmHg/20.6 mmHg para B/HCTZ y M/HCTZ, respectivamente (p < 0.0001). No se encontraron modificaciones significativas en los parámetros de laboratorio, al concluir el estudio en ninguno de los dos grupos. La disminución de la presión arterial (PA) con B/HCTZ se encuentra relacionada con un perfil de eventos adversos y cambios metabólicos semejante a los observados con otras drogas.

Factores predictores de sobrevida o de un segundo evento coronario en pacientes con un promer infarto agudo del miocardio / Predictive factors survival and for a second coronary event in patients with acute myocardial infarction

El pronóstico de los pacientes con un infarto agudo del miocardio está en relación a la gravedad de la obstrucción coronaria y al estado funcional residual del ventrículo izquierdo, que puede evaluarse a través de la fracción de expulsión. Con el fin de evaluar la utilidad de la fracción de expulsión y de algunos factores de riesgo cardiovascular, como predictores de un segundo infarto o de muerte tardía en los pacientes que han sufrido un primer infarto, se estudiaron 161 pacientes. Se investigó la ocurrencia de un segundo infarto o de muerte después del primer mes. Se siguieron a los pacientes durante 1 a 51 meses, y se les midió la fracción de expulsión por ecocardiograma transtorácico. La muestra incluyó 119 hombres y 42 mujeres, que contribuyeron con 3802 meses persona de seguimiento. La tasa de incidencia de segundo infarto fuede 0.01052 mes-1, y la de la mortalidad de 0.00342 mes-1. En el análisisi de sobrevida de Cox, la fracción de expulsión fue un adecuado indicador pronóstico y los sujetos con menos de 40 por ciento tuvieron un riesgo siete veces mayor de presentar un segundo infarto. La diabetes mellitus e hipertensión fueron los principales indicadores de muerte tardía. La fracción de expulsión es la variable más relacionada con la ocurrencia de un segundo infarto y junto con la historia de diabetes mellitus y de hipertensión predice en forma adecuada la mortalidad tardía posterior a un primer infarto del miocardio. La identificación de sujetos con mal pronóstico permite establecer acciones preventivas específicas. La fracción de expulsión es útil para categorizar a los sujetos en función a su pronóstico.

Sangrado faríngeo por actinomicosis amigdalina: reporte de un caso / Pharyngeal bleeding due to actinomycotic tonsilitis: a case report

Paciente femenino de 38 años de edad, se presenta con sangrado faríngeo al toser de pocas horas de evolución, sin otra sintomatología. Se practica amigdalectomía, resolviéndose el problema. El estudio histopatológico fue de amigdalitis crónica secundaria a actinomicosis. La entidad es poco común en la literatura mundial; es importante tenerla presente en el diagnóstico de afecciones amigdalinas y de sangrados faríngeos