Vigilancia de laboratorio de dengue y otros arbovirus en Cuba, 1970-2017 / Laboratory surveillance of dengue fever and other arboviruses in Cuba, 1970-2017

Los arbovirus constituyen una de las principales causas de emergencia en salud por la morbilidad y mortalidad que producen y el estrés sanitario que conllevan. Cuba no ha estado excenta de riesgo, y el enfrentamiento del dengue inicialmente y de otros arbovirus después, ha sido, y es, una prioridad de las máximas autoridades del país. La vigilancia de laboratorio de dengue se estableció desde inicios de la década del 70 aunque sus objetivos y estrategias han cambiado según la situación epidemiológica nacional y regional y la tecnología de diagnóstico disponible. Se destacan cuatro etapas en su desarrollo. En este trabajo se resumen las estrategias desarrolladas para la vigilancia de laboratorio de dengue y de otros arbovirus en el periodo de 1970 a 2017. Se describe además el papel desempeñado por el Instituto de Medicina Tropical, ¨Pedro Kouri¨ (IPK) como Laboratorio Nacional de Referencia(AU)

Arboviruses are one of the leading causes of health emergencies due to their morbidity and mortality and the sanitary stress they bring about. Cuba has not been free from risk, and the response first to dengue fever and then to other arboviruses has been and still is a priority for the country's top authorities. Laboratory surveillance of dengue fever was implemented in the 1970s, though its aims and strategies have evolved in keeping with the national and regional epidemiological situation, and the available diagnostic technology. Four stages stand out in the development of dengue laboratory surveillance. The present paper summarizes the strategies developed for laboratory surveillance of dengue fever and other arboviruses in the period 1970-2017. A description is also provided of the role played by Pedro Kourí Tropical Medicine Institute (IPK) as a national reference laboratory(AU)

Recognition of a multiple antigen peptide containing sequence from mimotope of the dengue type 3 virus NS4B protein by human antibodies.

OBJECTIVE: To evaluate the recognition of NS4B mimotope, as multiple antigen peptide (MAP), by dengue antibodies presents in serum samples from patients with different serotype infections. METHODS: A MAP containing mimotope sequence was synthesized and used to evaluate the recognition of NS4B mimotope as MAP by a panel of 66 human sera from dengue cases by an indirect ELISA assay. RESULTS: The MAP differentiated between sera from dengue viruses infected patients and sera from healthy individuals and the best reactivity was shown by serum from dengue type 3 virus patients. The recognition was more intense with serum from patients with secondary infection. CONCLUSIONS: The findings suggest the potential use of NS4B mimotope on the development of a multi-epitope diagnostic tool. These results are important for further immunogenicity studies.

Diagnóstico prenatal ultrasonográfico de higroma quístico / Prenatal Ultrasonographic Diagnosis of Cystic Hygroma

El higroma quístico es el resultado de segmentos del saco linfático yugular que están fuera de sitio o de la falla de los espacios linfáticos para conectar con los principales canales linfáticos y constituye un tumor líquido claro, limpio y transparente; se diagnostica por ecografía en el primer trimestre del embarazo, porque se aprecia una masa que sobresale en la pared posterior o lateral del cuello, su aparición se asocia a cariotipos anormales, por lo cual es indispensable un estudio de cariotipo humano. El higroma quístico está asociado a trisomía 21, 18 y 13, entre otras. Se reportó el caso de una paciente con embarazo de 13,2 semanas, a la cual se le realizó marcador genético, detectándose un feto con una tumoración quística en la región cervical. Se decidió la interrupción de la gestación, mediante el uso de misoprostol, obteniéndose un higroma quístico como resultado anatomopatológico, que reafirmó el diagnóstico ultrasonográfico.

Cystic hygroma is a result of jugular lymph sac segments that are out of place or the failure of the lymphatic spaces to connect with the main lymphatic channels. It is a clear, clean and transparent liquid tumor, diagnosed by ultrasound in the first trimester of pregnancy, for a mass that protrudes in the back or side wall of the neck can be seen, its onset is associated with abnormal karyotypes, which is indispensable for a study of the human karyotype. Cystic hygroma is associated with trisomy 21, 18 and 13, among others. A case of a patient with pregnancy of 13.2 weeks, who underwent genetic marker, detecting a fetus with a cystic tumor in the cervical region was reported. Interruption of pregnancy was decided by using misoprostol, a cystic hygroma was revealed that confirmed the ultrasonographic diagnosis.

Diagnóstico prenatal ultrasonográfico de higroma quístico / Prenatal Ultrasonographic Diagnosis of Cystic Hygroma

El higroma quístico es el resultado de segmentos del saco linfático yugular que están fuera de sitio o de la falla de los espacios linfáticos para conectar con los principales canales linfáticos y constituye un tumor líquido claro, limpio y transparente; se diagnostica por ecografía en el primer trimestre del embarazo, porque se aprecia una masa que sobresale en la pared posterior o lateral del cuello, su aparición se asocia a cariotipos anormales, por lo cual es indispensable un estudio de cariotipo humano. El higroma quístico está asociado a trisomía ,21, 18, y ,13, entre otras. Se reportó el caso de una paciente con embarazo de ,13,2, semanas, a la cual se le realizó marcador genético, detectándose un feto con una tumoración quística en la región cervical. Se decidió la interrupción de la gestación, mediante el uso de misoprostol, obteniéndose un higroma quístico como resultado anatomopatológico, que reafirmó el diagnóstico ultrasonográfico(AU)

Cystic hygroma is a result of jugular lymph sac segments that are out of place or the failure of the lymphatic spaces to connect with the main lymphatic channels. It is a clear, clean and transparent liquid tumor, diagnosed by ultrasound in the first trimester of pregnancy, for a mass that protrudes in the back or side wall of the neck can be seen, its onset is associated with abnormal karyotypes, which is indispensable for a study of the human karyotype. Cystic hygroma is associated with trisomy ,21, 18, and ,13, among others. A case of a patient with pregnancy of ,13.2, weeks, who underwent genetic marker, detecting a fetus with a cystic tumor in the cervical region was reported. Interruption of pregnancy was decided by using misoprostol, a cystic hygroma was revealed that confirmed the ultrasonographic diagnosis(AU)

Asymptomatic dengue infection in a Cuban population confirms the protective role of the RR variant of the FcgammaRIIa polymorphism.

The role of human Fcgamma receptors (FcgammaR) has been recognized considerably over the last years. These receptors vary in their affinity for IgG subclasses and the intracellular signals elicited by them. Allelic variants of FcgammaR genes may influence the biological phagocyte activity, accounting for an inherited pre-disposition to disease. The specific FcgammaRIIa (CD32) contains a polymorphic variant (H/R131) that has been associated to a reduced risk for developing dengue hemorrhagic fever (DHF). Here, we investigated the role of this polymorphism in a very well-characterized group of Cuban individuals with antecedents of DHF, dengue fever (DF), or subclinical dengue infection. The HH131 genotype was significantly associated with dengue disease, either DF (*P = 0.016; odds ratio = 4.425; 95% confidence interval = 1.10-20.52) or DHF (P = 0.00018; odds ratio = 10.56; 95% confidence interval = 2.33-54.64) with respect to the subclinical infection.

Phage-displayed antibody fragments recognizing dengue 3 and dengue 4 viruses as tools for viral serotyping in sera from infected individuals.

The current study shows the usefulness of dengue-3- and dengue-4-specific phage-displayed antibody fragments as tools for viral detection and serotyping in sera from infected individuals. C6/36 HT cells were inoculated with acute-phase sera from patients, and supernatants were collected daily and analyzed by ELISA using phage-displayed antibody fragments as serotype-specific detector reagents. Serotyping of most samples was possible as early as two to three days postinoculation. Results were comparable with those obtained by indirect immunofluorescence assay but were obtained in a shorter period of time (<1 week). Phage-displayed antibody fragments were better tools for diagnosis and serotyping than their soluble counterparts. Our approach combines the advantages of viral isolation and ELISA techniques. These results could be the basis for the development of a high-throughput method for identifying dengue virus serotypes, which is crucial for the management and control of the disease.

Caracterización clínico epidemiológica del retraso mental en la población del área de salud Manuel Díaz Legra Julio diciembre, 2007 / Clinical Epidemiological Characterization of Mental Retardation at Manuel Diaz Legra Area. July 2007-December 2007

Se realizó una investigación descriptiva en el período de julio a diciembre de 2006 en la Policlínica Manuel Díaz Legra de la provincia Holguín, con el objetivo de caracterizar el grupo de individuos atendidos por retraso mental según las variables clínico epidemiológicas seleccionadas. Se aplicó el instrumento elaborado por especialistas del Centro Nacional de Genética, validado en el estudio nacional, a 208 individuos con este diagnóstico y a sus tutores. Se observó que según grado de afectación intelectual, el retraso mental ligero fue el más frecuente con mayor cantidad de individuos afectados dentro del grupo de 11 a 20 años; predominó el sexo masculino y los factores causales prenatales. El total de los pacientes son atendidos en instituciones estatales o en la comunidad, aunque esta última forma se reflejó ligeramente más alta. Dentro de la atención brindada en las instituciones estatales se destacó el brindarles vínculo laboral y fue de mayor importancia para el grupo de retrasos mentales ligeros...(AU)

A descriptive investigation from July to September 2006, at Manuel Diaz Legra Polyclinic in Holguin province was carried out, aimed at characterizing a group of patients with mental retardation according to the clinical epidemiological variables that were studied . An instrument that was elaborated by specialists was applied. The results showed that mild mental retardation was the most frequent one. Patients between 11 and 20 years old were the most affected ones. The majority of patients were attended at institutions. Different intitutions offered jobs for patients with mild mental retardation...(AU)

Identification of Dengue-specific B-Cell Epitopes by Phage-display Random Peptide Library.

BACKGROUND: Dengue is the most important human viral disease transmitted by arthropod vectors. The availability of random peptide libraries (RPL) displayed on phage has provided a powerful tool for selecting sequences that mimic epitopes from microorganisms that are useful for diagnostic and vaccine development purposes. In this paper, we describe peptides that resemble the antigenic structure of B-cell epitopes of dengue virus identified from a phage-peptide library using human sera containing polyclonal antibodies against dengue virus. MATERIALS AND METHODS: Eighteen phage clones were isolated from the phage-display peptide library, J404, by affinity selection using human antisera against dengue virus type 3. These clones were tested for reactivity by ELISA with a panel of hyperimmune ascitic fluids (HAFs) containing antibodies either against all four dengue serotypes, West Nile virus (WNV) or Eastern equine encephalitis virus (EEEV) with control ascitic fluid (NAF) used as a negative control. RESULTS: Eight clones were recognized by HAFs against the four dengue serotypes, of which four significantly inhibited binding of anti-dengue antibodies to the virus. Two peptides with similar sequences to regions of NS3 and NS4B non-structural dengue virus proteins were identified. CONCLUSION: Our results suggest that these peptides could be used for the development of diagnostic tools for the detection of dengue virus infection and for a potential vaccine against this pathogen.

Selection of phage-displayed human antibody fragments on Dengue virus particles captured by a monoclonal antibody: application to the four serotypes.

Antibody fragments to the four Dengue virus serotypes were isolated from a human universal naïve library using phage display technology. Phage-displayed antibody fragments were selected on Dengue virus particles directly captured from infected Vero cells supernatant by an anti-dengue monoclonal antibody, in order to avoid laborious virus concentration/purification procedures. A total of nine phage-displayed antibody fragments were obtained. Seven of them were highly specific for three of the selector serotypes (two for Dengue 1, four for Dengue 3 and one for Dengue 4). One clone (Dengue 3-selected) cross-reacted with Dengue 1, whereas another (selected with Dengue 2) cross-reacted with the three remaining serotypes. The soluble variants of six antibody fragments recognized their target viruses when used at nanomolar and even subnanomolar concentrations. All phage-displayed antibody fragments were cross-reactive against several strains of distinct genotypes within the corresponding serotype(s). These antibody fragments are potentially useful for the future development of tools for viral diagnosis and serotype identification. The simple phage selection method on captured virus could be applied in a high throughput way to obtain larger panels of antibody fragments to Dengue virus for multiple applications.

West Nile Virus Infection in Humans and Horses, Cuba

West Nile virus was first detected in the Western Hemisphere during an outbreak of encephalitis in New York State in 1999 (1). Genetic analyses showed that the virus responsible for the 1999 outbreak was nearly identical to a WNV strain circulating in Israel in 1998 (2). Recent outbreaks of WNV disease in the United States and Canada have been accompanied by a high proportion of deaths in birds (3,4), substantial illness in equines (4,5), and thousands of cases of severe neurologic disease in humans (6). The range of WNV has rapidly expanded across the continental United States and Canada (7). WNV infection in humans, equines, and birds in Mexico (8), the Caribbean (9), and South and Central America (10,11) shows southward movement of the virus. Because Cuba is close to areas of the United States where WNV is endemic and because of recent evidence that suggests spread of WNV into the Caribbean, surveillance was established to monitor for WNV in Cuba. Beginning in 2002, the Medical Services and Ministry of Agriculture and Veterinarian Services of Cuba established a national surveillance program by using birds, horses, and humans to detect WNV activity. In this report, we summarize the key findings of surveillance activities(AU)

El virus del Nilo Occidental se detectó por primera vez en el Hemisferio Occidental durante un brote de encefalitis en el estado de Nueva York en 1999 (1). Análisis genéticos mostraron que el virus responsable del brote de 1999 fue casi idéntico a una cepa de virus que circulan en Israel en 1998 (2). Los recientes brotes de la enfermedad del VNO en Estados Unidos y Canadá se han visto acompañadas por una elevada proporción de muertes en las aves (3,4), enfermedad importante en equinos (4,5), y miles de casos de enfermedad neurológica en los seres humanos (6 ). La gama de virus se ha expandido rápidamente en todo el territorio continental de Estados Unidos y Canadá (7). La infección por el VNO en los seres humanos, equinos y aves en Mexico (8), el Caribe (9), América del Sur y Centroamérica (10,11) muestra el movimiento hacia el sur del virus. Porque Cuba está cerca de zonas de Estados Unidos, donde el virus es endémico y debido a las pruebas recientes sugieren que la propagación de virus en el Caribe, la vigilancia se estableció para supervisar VNO en Cuba. A partir de 2002, los Servicios Médicos y el Ministerio de Agricultura y Servicios Veterinarios de Cuba estableció un programa nacional de vigilancia mediante el uso de aves, caballos, y los seres humanos para la detección de VNO actividad. En este informe, resumimos las principales conclusiones de las actividades de vigilancia

West Nile Virus infection in humans and horses, Cuba.

A surveillance system to detect West Nile virus (WNV) was established in Cuba in 2002. WNV infection was confirmed by serologic assays in 4 asymptomatic horses and 3 humans with encephalitis in 2003 and 2004. These results are the first reported evidence of WNV activity in Cuba.

Amplificación dependiente de anticuerpos del virus dengue en cepas cubanas utilizando anticuerpos monoclonales / Dengue virus antibodies dependent amplification in Cuban strains by using monoclonal antibodies

Se describieron los diferentes comportamientos de anticuerpos monoclonales anti-dengue serotipo 2 (H3/6, 4G3) y anti-proteína recombinante de la envoltura del virus dengue cuando fueron enfrentados a diferentes cepas de los serotipos 2 y 4 de este virus (D2 Nueva Guinea C, A15 cepa cubana y A15 propagada 53 veces en cultivo de riñón de perro Beagly y D4 H-2412 cepa prototipo) en un ensayo de inmunoamplificación dependiente de anticuerpos. Los anticuerpos monoclonales han demostrado ser una herramienta eficaz para explicar que la neutralización y el incremento de la multiplicidad viral pueden realizarse como funciones biológicas separadas. Solamente el AcM H3/6 fue capaz de producir el fenómeno amplificación dependiente de anticuerpos frente a la cepa A15 con un incremento significativo en la multiplicación viral. Los AcMs 4G3 y 4B6 no fueron capaces de inmunoamplificar la multiplicación viral de las cepas estudiadas(AU)

Amplificación dependiente de anticuerpos del virus dengue en cepas cubanas utilizando anticuerpos monoclonales / Dengue virus antibodies dependent amplification in Cuban strains by using monoclonal antibodies

Se describieron los diferentes comportamientos de anticuerpos monoclonales anti-dengue serotipo 2 (H3/6, 4G3) y anti-proteína recombinante de la envoltura del virus dengue cuando fueron enfrentados a diferentes cepas de los serotipos 2 y 4 de este virus (D2 Nueva Guinea C, A15 cepa cubana y A15 propagada 53 veces en cultivo de riñón de perro Beagly y D4 H-2412 cepa prototipo) en un ensayo de inmunoamplificación dependiente de anticuerpos. Los anticuerpos monoclonales han demostrado ser una herramienta eficaz para explicar que la neutralización y el incremento de la multiplicidad viral pueden realizarse como funciones biológicas separadas. Solamente el AcM H3/6 fue capaz de producir el fenómeno amplificación dependiente de anticuerpos frente a la cepa A15 con un incremento significativo en la multiplicación viral. Los AcMs 4G3 y 4B6 no fueron capaces de inmunoamplificar la multiplicación viral de las cepas estudiadas.

The different behaviors of antidengue monoclonal antibodies serotype 2 (H3/6, 4G3) and antiprotein recombinant from the dengue virus sheath were described when they faced diverse strains from the serotypes 2 and 4 of this virus (D2 New Guinea C, A15 Cuban strain and A15 propagated 53 times in culture of Beagley dog kidney and D4 H-22412 prototype strain) in an immunoamplification assay dependent of antibodies. Themonoclonal antibodies have prove to be an efficient tool to explain that the neutralizatrion and increase of viral multiplicity may be carried out as separate biological functions. Only the H3/6 monoclonal antibdoy was capable of producing the amplification assay dependent phenomenon against the A15 strain with a significant rise in the viral multiplication. The 4G3 and 4B6 monoclonal antibodies were not capable of immunoamplifying the viral multiplication of the studied strains.

Diagnosis of dengue virus infection by the visual and simple AuBioDOT immunoglobulin M capture system.

The Dengue IgM Capture ELISA (MAC-ELISA) is the immunoenzymatic system recommended by the Pan American Health Organization and the World Health Organization for the serological diagnosis of dengue virus infection due to its high sensitivity, ease of performance, and use of a single acute-phase serum sample. However, tests with this enzyme-linked immunosorbent assay (ELISA) system are time-consuming and require equipment for washing, incubation, and reading of the results. AuBioDOT is a multistep visual diagnostic immunoassay that uses technology based on the immunoglobulin M (IgM) capture ELISA principle. This system uses white polyethylene opaque plates as the solid phase, colloidal gold as the marker, and silver ion amplification. It does not require special equipment, it is totally manually operated, and it can be performed in less than 1 h. The sensitivity and specificity of AuBioDOT for the detection of anti-dengue virus IgM antibodies were studied with a panel of 336 serum samples (150 serum samples from patients with suspected or serologically confirmed dengue virus infection, 186 serum samples from healthy blood donors and patients without dengue virus infection). The results were compared with those obtained by the MAC-ELISA. A sensitivity of 97.7% and a specificity of 97.1% were obtained. The concordance of the two tests was 97.3%, with a kappa index of 0.94. The application of AuBioDOT for the detection of anti-dengue virus IgM antibodies is recommended as an alternative method for the diagnosis of dengue virus infection, both for clinical diagnosis and for seroepidemiological surveillance. The system is useful under field conditions and in laboratories and requires little equipment.

MAC-ELISA and ELISA inhibition methods for detection of antibodies after yellow fever vaccination.

The IgM antibody capture ELISA (MAC-ELISA) and ELISA inhibition methods for the detection of antibodies against dengue virus were modified to detect antibodies against yellow fever virus. Tests were carried out in 21 persons vaccinated with 17D and compared with the Plaque reduction neutralizing test. Of 17 naive subjects vaccinated, 16 (94%) seroconverted using the MAC-ELISA test and 14 (82%) seroconverted (or >/=fourfold titer increase) in the ELISA inhibition method. Cross-reactivity was evaluated by both tests and resulted in a high specificity to IgM antibodies against yellow fever, when all the samples from vaccinated individuals were negative by MAC-ELISA using dengue antigen. However, 10.7% of the positive dengue sera from the Santiago de Cuba epidemic cross-reacted by MAC-ELISA using yellow fever antigen. ELISA inhibition method showed high cross-reactivity when the 21 sera pairs were worked with yellow fever and dengue antigens. The MAC-ELISA and ELISA inhibition methods have become indispensable tools in our laboratory in order to maintain a surveillance system for dengue and dengue hemorrhagic fever. They are relatively rapid, simple, and they do not require sophisticated equipment. Both MAC-ELISA and ELISA inhibition methods for yellow fever could be useful for diagnosis, surveillance and yellow fever vaccine evaluation.

Immune response to synthetic peptides of dengue prM protein.

The immunological activities of five synthetic peptides of the prM protein of dengue-2 (DEN-2) virus containing B cell epitopes were evaluated in BALB/c mice. Two peptides elicited neutralizing antibodies against all four DEN serotypes. Virus-specific proliferative responses were demonstrated in mice immunized with four of the five peptides, demonstrating the presence of T cell epitopes. Mice immunized with three of the five peptides conjugated with bovine albumin showed statistically significant levels (P<0.05) of protection when challenged with DEN-2 virus. These results could constitute the basis for the establishment of the role of DEN virus pre and M antigens in the development of anti-flaviviral vaccines.

Ensayo inmunoenzimático para la detección de anticuerpos monoclonales contra las proteínas E y NS1 del virus dengue

Se estandarizó un ELISA para la detección de anticuerpos monoclonales a las proteínas E y NS1 del virus dengue. Se aplicó un ELISA indirecto utilizando como fuente de antígeno células C6/36 inoculadas con la cepa A-15 aislada durante la epidemia de dengue 2 en 1981. Estas células fueron fijadas en placas ELISA a una concentración de 200 000 células/pozo. Se utilizó un control celular en condiciones similares. Para normalizar el sistema se emplearon anticuerpos monoclonales específicos a ambas proteínas. Se realizaron estudios a diferentes tiempos de incubación para determinar el momento de mayor expresión de estas proteínas en la membrana celular. Los resultados muestran una respuesta máxima a las 72 horas posinoculación para ambas proteínas, se obtuvo una sensibilidad para la detección de NS1 de 14,7 ng/mL y para la E de 1,43 ng/mL. Este sistema permite el tamizaje primario de anticuerpos monoclonales a las proteínas E y NS1 del virus dengue 2.

Empleo de una anticuerpo monoclonal anticomplejo dengue en la purificación viral / Use of a dengue anti-complex monoclonal antibody in viral purification

En este trabajo se reporta la purificación de los diferentes serotipos del virus dengue a partir de un anticuerpo monoclonal que reconoce un etiope presente en los 4 serotipos, acoplado a una matriz de Sepharose 4B activada con bromuro de cianógeno. Los resultados demuestran que el método empleado permite realizar el proceso de purificación con rapidez y alto grado de pureza

Empleo de una anticuerpo monoclonal anticomplejo dengue en la purificación viral / Use of a dengue anti-complex monoclonal antibody in viral purification

En este trabajo se reporta la purificación de los diferentes serotipos del virus dengue a partir de un anticuerpo monoclonal que reconoce un etiope presente en los 4 serotipos, acoplado a una matriz de Sepharose 4B activada con bromuro de cianógeno. Los resultados demuestran que el método empleado permite realizar el proceso de purificación con rapidez y alto grado de pureza.