A Somatic Coliphage Threshold Approach To Improve the Management of Activated Sludge Wastewater Treatment Plant Effluents in Resource-Limited Regions.

Effective wastewater management is crucial to ensure the safety of water reuse projects and effluent discharge into surface waters. Multiple studies have demonstrated that municipal wastewater treatment with conventional activated sludge processes is inefficient for the removal of a wide spectrum of viruses in sewage. In this study, a well-accepted statistical approach was used to investigate the relationship between viral indicators and human enteric viruses during wastewater treatment in a resource-limited region. Influent and effluent samples from five urban wastewater treatment plants (WWTPs) in Costa Rica were analyzed for somatic coliphage and human enterovirus, hepatitis A virus, norovirus genotypes I and II, and rotavirus. All WWTPs provide primary treatment followed by conventional activated sludge treatment prior to discharge into surface waters that are indirectly used for agricultural irrigation. The results revealed a statistically significant relationship between the detection of at least one of the five human enteric viruses and somatic coliphage. Multiple logistic regression and receiver operating characteristic curve analysis identified a threshold of 3.0 × 103 (3.5 log10) somatic coliphage PFU per 100 ml, which corresponded to an increased likelihood of encountering enteric viruses above the limit of detection (>1.83 × 102 virus targets/100 ml). Additionally, quantitative microbial risk assessment was executed for farmers indirectly reusing WWTP effluent that met the proposed threshold. The resulting estimated median cumulative annual disease burden complied with World Health Organization recommendations. Future studies are needed to validate the proposed threshold for use in Costa Rica and other regions.IMPORTANCE Effective wastewater management is crucial to ensure safe direct and indirect water reuse; nevertheless, few countries have adopted the virus log reduction value management approach established by the World Health Organization. In this study, we investigated an alternative and/or complementary approach to the virus log reduction value framework for the indirect reuse of activated sludge-treated wastewater effluent. Specifically, we employed a well-accepted statistical approach to identify a statistically sound somatic coliphage threshold value which corresponded to an increased likelihood of human enteric virus detection. This study demonstrates an alternative approach to the virus log reduction value framework which can be applied to improve wastewater reuse practices and effluent management.

Exposure of dogs to Rickettsia spp. in Costa Rica: Risk factors for PCR-positive ectoparasites and seropositivity.

Infection of dogs with Rickettsia spp. can result in inapparent, mild, or severe disease. Moreover, common dog ticks and fleas are able to transmit rickettsiae to nearby humans. In this study, the seroprevalence of spotted fever group (SFG) rickettsiae was determined in dogs of Costa Rica, as well as possible risk factors associated with exposure. An interview of owners and clinical examinations were performed in a country-wide sample of 441 dogs. IgG antibodies were determined in 399 dogs by indirect immunofluorescence assay (IFA) using antigens of Rickettsia rickettsii, R. amblyommatis, and R. felis. The presence of Rickettsia spp. gltA gene was evaluated by PCR in ticks and fleas. Poisson regression was performed to assess possible risk factors associated with seropositivity, as well as with having PCR-positive ticks and fleas. The overall seroprevalence to SFG rickettsiae was 10.0% (end titers 64 to 256). Rhipicephalus sanguineus s.l. (116/441; 26.3%) and Ctenocephalides felis (153/441; 34.7%) were the most common ectoparasites. Rickettsia DNA was detected in 30% (39/130) and 32.3% (56/173) of tick and flea pools, respectively. Seropositivity was significantly associated with mean age of 2 to 7 years, scrotal edema, walking problems, large size, and tick and flea infestation. Being a purebred dog was a possible protective factor. The presence of Rickettsia PCR-positive ticks was associated with being a purebred dog, while flea treatment was protective. Having PCR-positive fleas was associated with being purebred and the number of people in the dog's environment; protective factors were free roaming and being an outdoor dog. Results confirm that dogs in Costa Rica are exposed to different species of SFG rickettsiae. This may represent a risk to human health and underscores the need for accurate diagnosis in dogs and humans. Surveillance of rickettsial infection in canines may provide useful indicators to understand the epidemiology of these zoonoses.

Detection of rickettsiae in fleas and ticks from areas of Costa Rica with history of spotted fever group rickettsioses.

Outbreaks of spotted fevers have been reported in Costa Rica since the 1950s, although vectors responsible for transmission to humans have not been directly identified. In this study, species of Rickettsia were detected in ectoparasites from Costa Rica, mostly from five study sites where cases of spotted fevers have been reported. Ticks and fleas were collected using drag cloths or directly from domestic and wild animals and pooled according to species, host, and location. Pools were analyzed initially by PCR to detect a fragment of Rickettsia spp. specific gltA gene, and those positive were confirmed by detection of htrA and/or ompA gene fragments. Partial sequences of the gltA gene were obtained, as well as at least one ompA and/or ompB partial sequence of each species. Rickettsia spp. were confirmed in 119 of 497 (23.9%) pools of ticks and fleas analyzed. Rickettsia rickettsii was identified in one nymph of Amblyomma mixtum and one nymph of Amblyomma varium. Other rickettsiae present were 'Candidatus Rickettsia amblyommii' in A. mixtum, Amblyomma ovale, Dermacentor nitens, and Rhipicephalus sanguineus s. l.; Rickettsia bellii in Amblyomma sabanerae; Rickettsia felis in Ctenocephalides felis; and Rickettsia sp. similar to 'Candidatus R. asemboensis' in C. felis, Pulex simulans, A. ovale, and Rhipicephalus microplus. Results show the presence of rickettsiae in vectors that may be responsible for transmission to humans in Costa Rica, and evidence suggests exposure to rickettsial organisms in the human environment may be common. This is the first study to report R. rickettsii in A. varium and in A. mixtum in Costa Rica.

Exposure of dogs to spotted fever group rickettsiae in urban sites associated with human rickettsioses in Costa Rica.

The zoonotic transmission cycles of Rickettsia rickettsii and other spotted fever group (SFG) rickettsiae in Latin America have usually been associated with rural or sylvatic environments, although domestic dogs can be implicated in more populated settings. In this study, exposure of dogs to SFG rickettsiae in the Greater Metropolitan Area of Costa Rica was investigated. Dogs from sites associated with human cases and from dog shelters were evaluated by indirect immunofluorescence assay (IFA) using antigen of SFG rickettsiae. Rickettsia spp. were detected in ectoparasites by polymerase chain reaction (PCR). A total 18.5% (31/168) of dogs associated with human cases and 6.8% (11/161) of dogs in shelters had IgG end titers≥64 to Rickettsia spp. The odds of being seropositive were greater in dogs from areas associated with human cases when compared to shelters (OR: 3.2; 95% C.I: 1.5-5.6). Rhipicephalus sanguineus sensu lato (s. l.) was present in all sites associated with human cases. Rickettsia felis URRWXCal2 and R. felis-like RF2125 were detected in Ctenocephalides felis, and Rickettsia sp. IbR/CRC in Ixodes boliviensis. Results demonstrate that dogs from the main urban center of Costa Rica have been exposed to SFG rickettsiae, especially in areas with known human infection. Both human and animal health sectors must be aware of possible rickettsial diseases in urban areas, where dogs may also serve as sentinels for human infection.

Pathogenic potential of a Costa Rican strain of 'Candidatus Rickettsia amblyommii' in guinea pigs (Cavia porcellus) and protective immunity against Rickettsia rickettsii.

'Candidatus Rickettsia amblyommii' is a spotted fever group rickettsia that is not considered pathogenic, although there is serologic evidence of possible infection in animals and humans. The aim of this study was to evaluate the pathogenic potential of a Costa Rican strain of 'Candidatus R. amblyommii' in guinea pigs and determine its capacity to generate protective immunity against a subsequent infection with a local strain of Rickettsia rickettsii isolated from a human case. Six guinea pigs were inoculated with 'Candidatus R. amblyommii' strain 9-CC-3-1 and two controls with cell culture medium. Health status was evaluated, and necropsies were executed at days 2, 4, and 13. Blood and tissues were processed by PCR to detect the gltA gene, and end titers of anti-'Candidatus R. amblyommii' IgG were determined by indirect immunofluorescence. To evaluate protective immunity, another 5 guinea pigs were infected with 'Candidatus R. amblyommii' (IGPs). After 4 weeks, these 5 IGPs and 3 controls (CGPs) were inoculated with pathogenic R. rickettsii. Clinical signs and titers of anti-Rickettsia IgG were determined. IgG titers reached 1:512 at day 13 post-infection with 'Candidatus R. amblyommii'. On day 2 after inoculation, two guinea pigs had enlarged testicles and 'Candidatus R. amblyommii' DNA was detected in testicles. Histopathology confirmed piogranulomatous orchitis with perivascular inflammatory infiltrate in the epididymis. In the protective immunity assay, anti-Rickettsia IgG end titers after R. rickettsii infection were lower in IGPs than in CGPs. IGPs exhibited only transient fever, while CGP showed signs of severe disease and mortality. R. rickettsii was detected in testicles and blood of CGPs. Results show that the strain 9-CC-3-1 of 'Candidatus R. amblyommii' was able to generate pathology and an antibody response in guinea pigs. Moreover, its capacity to generate protective immunity against R. rickettsii may modulate the epidemiology and severity of Rocky Mountain spotted fever in areas where both species circulate.

Detection of an undescribed Rickettsia sp. in Ixodes boliviensis from Costa Rica.

Ixodes boliviensis is a tick of carnivores that is common on domestic dogs. The only Rickettsia that has been detected previously in this species is 'Candidatus Rickettsia andeanae'. We report the detection of an undescribed Rickettsia sp., named strain IbR/CRC, in I. boliviensis collected from dogs in Costa Rica. Analyses of gltA, ompA, and htrA partial sequences place Rickettsia sp. strain IbR/CRC in the group of R. monacensis, also close to an endosymbiont of Ixodes scapularis and other undescribed rickettsiae. It was not possible to isolate Rickettsia sp. strain IbR/CRC in Vero E6 or C6/36 cell lines. Isolation and further characterization of Rickettsia sp. strain IbR/CRC and the other undescribed rickettsiae are required to determine their taxonomic status and pathogenic potential.

A fatal urban case of rocky mountain spotted fever presenting an eschar in San Jose, Costa Rica.

This study reports the first urban human case of Rocky Mountain spotted fever caused by Rickettsia rickettsii, in Costa Rica. An 8-year-old female who died at the National Children's Hospital 4 days after her admission, and an important and significant observation was the presence of an "eschar" (tache noire), which is typical in some rickettsial infections but not frequent in Rocky Mountain spotted fever cases.

Rickettsia felis in Ctenocephalides felis from Guatemala and Costa Rica.

Rickettsia felis is an emerging human pathogen associated primarily with the cat flea Ctenocephalides felis. In this study, we investigated the presence of Rickettsia felis in C. felis from Guatemala and Costa Rica. Ctenocephalides felis were collected directly from dogs and cats, and analyzed by polymerase chain reaction for Rickettsia-specific fragments of 17-kDa protein, OmpA, and citrate synthase genes. Rickettsia DNA was detected in 64% (55 of 86) and 58% (47 of 81) of flea pools in Guatemala and Costa Rica, respectively. Sequencing of gltA fragments identified R. felis genotype URRWXCal(2) in samples from both countries, and genotype Rf2125 in Costa Rica. This is the first report of R. felis in Guatemala and of genotype Rf2125 in Costa Rica. The extensive presence of this pathogen in countries of Central America stresses the need for increased awareness and diagnosis.

First report of the isolation and molecular characterization of Rickettsia amblyommii and Rickettsia felis in Central America.

During 2010, 15 adult ticks, identified as Amblyomma cajennense, were collected from horses in Cahuita and Turrialba districts, whereas 7 fleas, identified as Ctenocephalides felis, were collected from a dog in San Jose city, Costa Rica. In the laboratory, three A. cajennense specimens, two from Cahuita and one from Turrialba, were individually processed for rickettsial isolation in cell culture, as was a pool of seven fleas. Rickettsiae were successfully isolated and established in Vero cell culture from the three ticks and from a pool of seven fleas in C6/36 cell culture. The three tick isolates were genotypically identified as Rickettsia amblyommii, and the flea isolate was identified as Rickettsia felis through DNA sequencing of portions of the rickettsial genes gltA, ompA, and ompB of each isolate. In addition, other seven ticks were shown to contain rickettsial DNA. Polymerase chain reaction products of at least two of these ticks were sequenced and also showed to correspond to R. amblyommii. Overall, 66.7% (10/15) of the A. cajennense adult ticks were found to be infected with rickettsiae. This is the first report of a successful isolation in cell culture of R. amblyommii and R. felis from Central America.

Determinación de subtipos del virus respiratorio sincicial en muestras positivas por el virus, aisladas en el Hospital Nacional de Niños / Detection of human respiratory syncytial virus subtypes A and B in hospitalized children in Costa Rica

Objetivo: El virus respiratorio sincicial, VRS, es un pneumovirus de la familia Paramyxovridae, que causa enfermedad severa del tracto respitaroio inferior en neonatos y niños pequeños, especialmente en los primeros años de vida. Es responsable de constantes hospitalizaciones y visitas a los servicios de emergencias. Se han identificado dos subtipos: VRS-A y VRS-B, mediante anticuerpos monoclonales y técnicas moleculares. El objetivo de este estudio fue establecer por primera vez la circulación de ambos subtipos del VRS, en muestras positivas de niños hospitalizados durante el pico estacional de 2008, en el Hospital Nacional de Niños, HNN. Métodos: Se analizaron 49 muestras de aspirados nasofaríngeos de niños hospitalizados, de un total de 578, de las cuales 197 fueron previamente positivas para VRS por inmunofluorescencia directa. Se realizó cultivo celular, y un RT-PCR múltiple, estandarizado en el laboratorio, para detectar VRS-A y VRS-B. Resultados: La frecuencia del VRS fue del 34 por ciento en el HNN, para agosto y septiembre de 2008. De las 49 muestras analizadas por RT-PCR, 41, 84 por ciento, fueron positivas, 34, 83 por ciento, por el subtipo A y 7, 17 por ciento, por el B; 8 fueron negativas. Ningún paciente presentó infección mixta y no hubo diferencia entre los síntomas, la edad o el origen geográfico de los niños. El cultivo fue positivo solo en el 30 por ciento de las muestras. Conclusión: La frecuencia del VRS para el periodo en estudio fue del 34 por ciento de las muestras analizadas en aspirados nasofaríngeos. Este es el primer reporte de la detección de los subtipos A y B del VRS, en una pequeña cohorte del HNN, confirmados por un RT-PCR múltiple estandarizado en el laboratorio.

Molecular characterization of Rickettsia rickettsii isolated from human clinical samples and from the rabbit tick Haemaphysalis leporispalustris collected at different geographic zones in Costa Rica.

Five strains of spotted fever group (SFG) rickettsiae previously isolated from human clinical cases and from the tick Haemaphysalis leporispalustris were used for molecular characterization in this study to establish their genetic relationship compared with the prototype Rickettsia rickettsii strain Sheila Smith. Samples were tested by polymerase chain reaction (PCR) targeting the rickettsial genes gtlA, ompA, and ompB. PCR products of the latter two genes were DNA sequenced and compared with available sequences in GenBank. The ompA partial sequences of the five Costa Rican isolates showed 100% identity to several R. rickettsii sequences available in GenBank, including the sequence of the virulent reference strain Sheila Smith, whereas the ompB partial sequences of the five Costa Rican isolates showed 99.8-100% identity to R. rickettsii sequences from GenBank. This study showed the first molecular detection of R. rickettsii isolates from Rocky Mountain Spotted Fever patients and from the rabbit tick H. leporispalustris in different geographical zones in Costa Rica.

Reduced expression of Jak-1 and Tyk-2 proteins leads to interferon resistance in hepatitis C virus replicon.

BACKGROUND: Alpha interferon in combination with ribavirin is the standard therapy for hepatitis C virus infection. Unfortunately, a significant number of patients fail to eradicate their infection with this regimen. The mechanisms of IFN-resistance are unclear. The aim of this study was to determine the contribution of host cell factors to the mechanisms of interferon resistance using replicon cell lines. RESULTS: HCV replicons with high and low activation of the IFN-promoter were cultured for a prolonged period of time in the presence of interferon-alpha (IFN-alpha2b). Stable replicon cell lines with resistant phenotype were isolated and characterized by their ability to continue viral replication in the presence of IFN-alpha. Interferon resistant cell colonies developed only in replicons having lower activation of the IFN promoter and no resistant colonies arose from replicons that exhibit higher activation of the IFN promoter. Individual cell clones were isolated and nine IFN resistant cell lines were established. HCV RNA and protein levels in these cells were not altered by IFN- alpha2b. Reduced signaling and IFN-resistant phenotype was found in all Huh-7 cell lines even after eliminating HCV, suggesting that cellular factors are involved. Resistant phenotype in the replicons is not due to lack of interferon receptor expression. All the cell lines show defect in the JAK-STAT signaling and phosphorylation of STAT 1 and STAT 2 proteins were strongly inhibited due to reduced expression of Tyk2 and Jak-1 protein. CONCLUSION: This in vitro study provides evidence that altered expression of the Jak-Stat signaling proteins can cause IFN resistance using HCV replicon cell clones.

Development of a Lepto-IgM EIACR test to diagnose leptospirosis disease in Costa Rican patient samples.

Leptospirosis is an endemic disease throughout Costa Rica, which could be misdiagnosed because manifestations of this febrile disease may vary from mild flu-like symptoms to severe illness involving vital organs such as liver and lungs. Therefore an early specific diagnosis is important to ensure a favorable clinical outcome. The purpose of this study was to develop a Leptospira sp. anti-IgM EIA (Lepto-IgM EIACR) test and to compare it using Lepto-Dipstick IgM (Lepto-DS IgM) and PanBio-EIA IgM with the Microscopy Agglutination test (MAT) as a reference assay. Sera from 736 healthy blood donors were used as negative controls to calculate specificity (97.1%), Confidence Interval 95 (CI (96-98). Cross reactivity was evaluated in 268 patient samples with 6 different diseases. Dengue and measles had the highest cross reactivity (16%) while rubella showed the lowest (3%). To determine the sensitivity of the Lepto- IgM EIACR, 33 samples positive by MAT of 96 paired samples from patients with symptoms related to leptospirosis infection were tested. Lepto-IgM EIACR reached a sensitivity of 90.9% (CI 81-100), while Lepto-DS IgM was 48.5% (CI (31-66). The most frequent serovars detected by MAT in these paired samples were Hebdomadis 14.7%, Hardjo 11.8%, Pomona 8.8% and Icterohaemorrhagiae 5.9%. Furthermore 59 febrile patient samples were tested initially with PanBio-EIA IgM, 21 samples (35%) were positive. When these samples were re-tested by Lepto-IgM EIACR and Lepto-DS IgM, 80.9% and 33% were positive, respectively. The results of the evaluation indicate that Lepto-IgM EIACR test could be a good alternative to detect acute leptospirosis in Costa Rica.

Development of a Lepto-IgM EIACR test to diagnose leptospirosis disease in Costa Rican patient samples

Leptospirosis es una enfermedad febril endémica en Costa Rica que puede ser mal diagnosticada, ya que sus manifestaciones varían desde síntomas similares a gripe, hasta enfermedades severas que afectan órganos vitales como el riñón, hígado o pulmón. Por ello es importante un diagnóstico específico y temprano. El propósito de este estudio fue desarrollar un ELISA anti-IgM (Lepto-IgM EIACR) y compararlo con Lepto-Dipstick IgM (Lepto-DS IgM) y PanBio-EIA IgM utilizando como prueba de referencia la Microaglutinación MAT. Se usó el suero de 736 donadores de sangre como control negativo para determinar la especificidad del ensayo (97,1 po rciento, CI (96-98). Pruebas de reacción cruzada fueron analizadas en 268 muestras de pacientes distribuidos en 6 enfermedades. Dengue y Sarampión mostraron los valores más altos de reactividad (16 por ciento) y Rubeola el más bajo (3 por ciento). La sensibilidad de Lepto- IgM EIACR fue 90,9 por ciento (CI (81-100), mientras que Lepto-DS IgM alcanz¢ un 48,5 porciento (CI (31-66), la cual se calculó a partir de 33 sueros pareados de 96, que fueron enviados para el diagnóstico de Leptospira sp. Las serovariedades más prevalentes detectadas por MAT en estas muestras fueron: Hebdomadis 14,7 por ciento, Hardjo 11,8 por ciento, Pomona 8,8 por ciento e Icterohaemorrhagiae 5,9 por ciento. Adicionalmente, de 59 muestras agudas de pacientes febriles que fueron inicialmente analizadas por PanBio-EIA IgM, 21 resultaron positivas, de éstas, Lepto-IgM EIACR y Lepto-DS IgM, detectaron el 80,9 por ciento y 33,3 por ciento respectivamente. Los resultados de la evaluación indican que Lepto-IgM EIACR podría ser una buena alternativa para detectar leptospirosis aguda en Costa Rica.

Patrones indeterminados de Western Blot en sueros reactivos por anticuerpos contra los virus linfotrópicos de células T tipo I/II, HTLV I/II, en donantes de sangre en Costa Rica / Western Blot indeterminate patterns in reactive serum by antibodies against T lynphotropic virus I/II, HTLV I/II, in blood donors in Costa Rica

Los virus linfotrópicos humanos tipo I y II, HTLV I/II, son retrovirus asociados a diferentes patologías. El HTLV I fue el primer retrovirus relacionado con enfermedad y ocasiona principalmente dos tipos de patologías: la leucemia o linfoma de células T del adulto, LTA, y la paraparesia espástica tropical, PET. El HTLV-II se ha asociado a cuadros neurológicos similares. Centroamérica, América del Sur y el Caribe se definen como áreas de alta prevalencia. Para prevenir la transmisión de la infección de estos retrovirus, se ha implementado el tamizaje de la donación sanguínea en muchos países, incluido Costa Rica. En donadores tamizados la técnica de Western Blot, WB, ha demostrado una actividad incompleta de anticuerpos contra los antígenos virales. Estos patrones se definen como indeterminados. Entre diciembre del 2002 y marzo del 2006 se reportaron los siguientes resultados de WB al evaluar sueros reactivos por ensayo inmunoenzimático: 39 (0,02 por ciento) donantes positivos, 254 (0,14 por ciento) indeterminados y 113 (0,06 por ciento) negativos. Se seleccionaron 42 muestras indeterminadas y 25 positivas para ser analizadas por un sistema comercial (HTLV I/II Blot 2.4); las positivas se clasificaron como: 15 HTLV I, 8 HTLV II y dos muestras indeterminadas. Del grupo de indeterminados se presentaron 4 resultados no concordantes: 1 HTLV II, 1 HTLV y 2 negativos. Se demostró que, en muestras nacionales, patrones positivos débiles pueden estar relacionados a WB indeterminados o a reactividad parcial de infección por HTLV II...

Human T lymphotropic virus type I and II (HTLV I/II) are retroviruses associated with different clinical manifestations. HTLV I was the first retrovirus associated to human disease, and it is the etiological agent of two main pathologies: adult`s T-cell leukemia (ATL) and myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-II has been related to similar neurological disorders. Central America, South America and the Caribbean are areas of high prevalence.In many countries, including Costa Rica, blood screening has been implemented to prevent retroviral blood transmission. Applying the Western Blot (WB) technique, screening for HTLV I/II in blood donors has shown...

Detección de anticuerpos contra los virus linfotrópicos de células T Tipo I, II, HTLV I, II, como medida de seguridad sanguínea en donantes de sangre en Costa Rica, mayo del 2002 a diciembre del 2004 / Detection of antibodies against viruses linfotropicos T cell type I, II, HTLV I, II, as a security measure blood in blood donors in Costa Rica, May 2002 December 2004

Los Virus Linfotrópicos Humanos tipo I y II, HTLV I, II, fueron los primeros retrovirus descritos y aislados en 1980. Tienen distribución mundial y son endémicos en el sur de Japón, el Caribe, algunos países del Sur y Centro América, Africa occidental y algunas otras poblaciones. Aunque la mayoría de infectados permanecen asintomáticos por largos períodos, el HTLV I es el agente causal de la leucemia linfoma de células T del adulto, LTA, y de la Paraparesia Espástica Tropical, PET o mielopatía asociada, MAH. El HTLV II se identificó inicialmente en un paciente con leucemia peluda de células T, pero se requieren más estudios para establecer la relación entre ambos. Dos de las principales vías de transmisión son la transfusión sanguínea o por compartir agujas de individuos infectados en drogadicción. Para controlar la transmisión de la infección en Costa Rica, se inició en el año 2002 un proyecto de la Sección de Laboratorios Clínicos de la CCSS, para la tamización de anticuerpos contra estos retrovirus a todos los donantes de sangre, fecha histórica para nuestro país por ser el primero en tener una cobertura del 100 por ciento de los donantes en América Latina...

During 1980, Human T lymphotropic virus (HTLV-I /II) were the first retrovirus identified and isolated.The geographic distribution of the virus is global, with endemic regions like south Japan, the Caribbean islands, western Africa, some South and Central America countries and other specific populations.Most infected patients remain without symptoms for long periods of time but association with human disease has been demonstrated. HTLV-II has been linked to adult T-cell leukemia/lymphoma (ATL/ATLL) and is also the causative agent of a neurological disorder termed HTLV-II associated Myelopathy/ttropical Spastic Parapesis.HTLV-II was first identified in a patient with hairy-cell leukemia, however better studies are needed to establish the relation between both. HTLV can be transmitted by blood transfusion and sharing of needles and syringes. During 2002, Costa Rica became the first Latin American country with 100% coverage of blood donors. In this year, the Sección de Laboratorios Clínicos de la CCSS began as a project the screening for antibodies against HTLV in order to avoid transmission through this route. Of 106958 blood donors, 582 (0,54%) were initially reactive by enzyme-immunolinked assay (EELISA), 272 (46,7%) were reactive in duplicated with the same ELISA and they were analyzed by a second ELISA and 232 were confirmed with an "in-house "Western Blot (WB).. Those represent the 0.25% of the initial population. Twenty seven samples (0.03%) confirmed positives and 136 (0.13%) were indeterminate. A commercial WB was performed with 13 of these positive samples, 7 were HTLV-II, 5 were HTLV-III and 1 was an indeterminate pattern...

Infección por Chlamydia Trachomatis en un grupo de mujeres de alto riesgo, trabajadoras del sexo en Costa Rica / Infection by Chlamydia Trachomatis in a group of women of high risk, workers of sex in Costa Rica

Las clamidias son los patógenos más importantes en las enfermedades de transmisión sexual en todo el mundo. Sólo para Estados Unidos se estima que ocurren más de 4 millones de infecciones clamidiales por año. En Costa Rica pocos estudios de la infección por Chlamydia trachomatis (CT) han sido publicados por la falta de introducción de pruebas sensibles y específicas para su tamizaje y diagnóstico. Este estudio pretende determinar la presencia de la infección por CT en un grupo de mujeres trabajadoras de sexo (MTS) para demostrar la necesidad de diagnóstico y tomar las medidas adecuadas de prevención y control. En un estudio descriptivo transversal prospectivo, un total de 457 MTS fueron analizadas, se obtuvieron muestras de endocervical y orina, así como datos epidemiológicos. La prueba de PCR Roche Diagnostic fue usada para detectar la infección por C. Trachomatis. Se determina un 14.7 por ciento de prevalencia de infección afectando principalmente a los grupos etarios de 16 a 34 años así, como su relación con comportamientos de riesgo tales como, edad temprana de inicio de relaciones sexuales (10 a 19 años), baja escolaridad (66 por ciento primaria o menos), múltiples compañeros sexuales (50.7 por ciento de 11 a 50 por semana), no uso del preservativo (43.8 por ciento). No se encontró relación entre la infección por CT y el diagnóstico clínico sintomatológico lo que evidencia la necesidad de la implementación de un método de diagnóstico como las pruebas de amplificación nucleica de gran sensibilidad y especificidad como, su aplicación en diferentes tipos de muestras: endocervicales, uretrales, orina que permitan la detección y prevención de la infección, para brindar los tratamientos oportunos y la disminución de la morbilidad y la transmisión.

The Chlamydia are the most important pathogens in the sexual transmission diseases over the world. An estimated of 4 million Chlamydia infection occurs annually in the United States. In Costa Rica, few studies of the Chlamydia trachomatis (CT) infection have been published because of the lack of sensitive and specific testing introduction methods for screening and diagnostic. This study tries to determine the presence of the infection by CT in a group of women sex workers (WSW) to demonstrate that we must implemented the diagnostic and take the measures from prevention and control. In one descriptive, prospective and transversal study, a total of 457 WSW were analyzed. Endocervicales, urine samples and epidemiological data were obtained from the study. C. Trachomatis infection was detected with the PCR Roche Diagnostic Test. In this study a 14.7% of prevalence is determined, affecting mainly groups of people from 16 to 34 years old. Besides, a connection with early sexual intercourse (10 to 19 years), low schooling (primary 66% or less), multiple sexual partners (50.7% from 11 to 50 per week), non use of condom (43.8%) was found. In the study there was not relation between infection by CT and the clinical diagnostic symptoms that demonstrates the necessity of the implementation of a diagnostic method, like nucleic acid amplifi cation tests, for the great sensitivity and specifi city, and its application in different specimens: urethral, endocervicales, urine that allow the detection and prevention of the infection, to offer the proper treatments and the reduction of the morbidity and the transmission.

HBx M130K and V131I (T-A) mutations in HBV genotype F during a follow-up study in chronic carriers.

BACKGROUND: Around 400 million people worldwide are chronically infected with Hepatitis B virus (HBV). An estimated 10% of these chronic patients develop progressive liver damage including cirrhosis and Hepatocellular Carcinoma (HCC). The HBx gene encodes a protein of 154 amino acids which is a transactivator and has been associated with HBV pathogenesis. A change in the amino acid sequences at positions 130 and 131 in the HBV-X protein (M130K and V131I) produced by T-A point mutations at the nucleic acids level has been associated with severe liver damage and HCC in patients from China and Africa. Further, such changes have been proposed as a prognostic marker for progressive liver damage and HCC. The purpose of this study was to determine if T-A mutations are present in HBV chronic carriers with genotype F (the major genotype in Costa Rica) and further, if these mutations are associated with HBV disease progression in Costa Rica HBV patients from 1972 to 1985. RESULTS: Serum samples from 50 HBV positive individuals were amplified and directly sequenced, 48 belonged to genotype F, 1 from genotype D and another was classified as D or E. T-A mutations were absent in 17 acute patients who recovered, but was present in 12 of 29 chronic carrier samples (42.8%), in one sample the T-A mutations were detected as early as 29 days after clinical onset of disease. In 17 carriers with available liver biopsies, T-A mutations were found in 8 sera of 13 (61.5%) classified as moderate or severe, and none in 4 biopsies with mild liver damage. However, it was not possible to demonstrate a statistical association between the presence of T-A mutations and moderate/severe liver damage, using a Fischer exact test, 1 tail, p = 0.05. In 4 patients HCC was diagnosed, and 2 of them presented the T-A mutations in their sera. CONCLUSION: T-A mutations were found in HBV genotype F in chronic carriers but not in patients who recovered from acute infection. These mutations could be developing early during infection although the possibility of infection with the mutant virus could not be excluded. More studies are necessary to establish if the T-A mutation can be used as a prognostic marker for severity of liver disease in patients infected with HBV.

Prevalencia de anticuerpos contra el trypanosoma cruzi en donantes de sangre de la seguridad social Costa Rica, setiembre 2003 - setiembre 2004 / Prevalence of antibodies against trypanosoma cruzi in donors of blood of the social security Costa Rical, September 2003 - September 2004

La enfermedad de Chagas es una infección ocasionada por el Trypanosoma cruzi, parásito responsable de 16 a 18 millones de personas infectadas en América Latina de las cuales 50.000 mueren cada año. Una de las principales fuentes de transmisión es por transfusión sanguínea. A partir de setiembre del 2003 en los Bancos de Sangre de la C.C.S.S. se implementó la tamización del 100 por ciento de los donantes de todo el territorio nacional. Cincuenta y tres mil trescientos treinta y siete muestras de suero, fueron recolectadas de setiembre del 2003 a setiembre del 2004 y analizados por EIA con tres diferentes fuentes antigénicas (proteínas recombinantes, péptidos homólogos y lisado proteíco de la Cepa Brenner para el WB). De las muestras analizadas, 305 (0,6 por ciento) fueron inicialmente reactivas. De éstas, 176 (58 por ciento) resultaron repetidamente reactivas (RR) por el EIA-ICMRT de tamizaje. De las RR 122 (69 por ciento) mostraron resultados discrepantes entre los dos EIA realizados, 42 (24 por ciento) fueron positivos por los dos ensayos y 12 (7 por ciento) no pudieron ser evaluadas. De las muestras RR por el EIA-ICMRT 39 (22 por ciento) resultaron positivas por WB, 65 (37 por ciento) fueron indeterminadas y 56 (32 por ciento) negativas, 15 muestras quedaron pendientes. En el estudio se obtuvo 0,6 por ciento de reactividad inicial, ligeramente mayor a lo reportado en los últimos tres años en el país. La prevalencia obtenida fue 0.08 por ciento el porcentaje más bajo del área Centroamericana. Al comparar los resultados obtenidos en el EIA-ICMRT y el WB, se observa una mayor correlación entre las muestras con DO altas >2,0 y un resultado positivo por WB según el criterio establecido. En general las reacciones negativas o indeterminadas por WB se presentaron en muestras con DO<2,0 y contra proteínas de pesos moleculares bajos (15-50kD). El estudio demuestra la importancia de realizar varias pruebas diagnósticas de alta sensibilidad y especificidad...

The Chagas' disease is a infection caused by Trypanosoma cruzi parasite; it is responsible of infestation of 16 to 18 people in Latin America with 50,000 deaths every year. The main source of transmission is for blood transfusion. Since September 2003, Caja Costarricense de Seguro Social’s Blood Banks have implemented the screen in about 100% of donors of the country. The 53307 serum samples were collected in the period of September 2003 to September 2004, and they were tested with the EIA with three types of antigenic sources (recombinant protein, homolog peptides, protein lysate of Strain Brenner for WB). Of the tested samples, 305 (0.6%) were beginning reactives. Of these, 176 (58%) were repeat reactives (RR) for the test EIA-ICMRT. Of the RR, 122 (69%) shown discrepancy between two EIA tested, 42 (24%) were positives for the two assays and 12 (7%) did not have be evaluated. The RR samples tested for EIA-ICMRT, 39 (22%) were positives for WB, 65 (37%) were indetermined, 56 (32%) were negatives, and 15 samples stayed pending. The results of the study got 0.6% of initial positive test; it was a light increment with respect to results of the 3 years in the country. The prevalence was 0.08%, It is the lowest in Central America. Comparing the results between EIA-ICMRT and WB, it was a bigger correlation between the samples with DO highs >2, 0 and a positive result for WB according the established criterion. In general, the negative or indeterminate results for WB correspond to samples with DO<2, 0 and against proteins with low molecular weights (15-50 kD). The study shown the importance to do certain diagnostic assays of high sensibility and specificity for determine the real prevalence and for the control of transmission of infection with the proposal of offer blood banks to costarican people and rational use of them.