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This study evaluates the utility and cost effectiveness of empirical and prophylactic antibiotic treatment of leptospirosis compared with conventional management. We developed decision trees comparing empirical antibiotic treatment (within 4-7 days of symptom onset) or prophylaxis to conventional antibiotic treatment (initiated 7 days post-onset). Costs were calculated using both US and Barbados pricing. Empirical treatment provided slightly lower probability of survival, while prophylactic treatment resulted in slightly higher survival rates. Antibiotic treatment initiated after 4-7 symptomatic days was ineffective in preventing serious health outcomes, but cost less with the exception of azithromycin (US pricing). Empirical treatment in Barbados cost less than conventional treatment. Prophylaxis reduced rare serious health outcomes and resulted in significant cost savings for the United States and Barbados. Prophylactic therapy for high-risk individuals or prompt diagnosis and early treatment (before 4 days of symptoms) appear to be cost-effective approaches to prevent severe complications of leptospirosis.

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OBJECTIVE: To present a quantitative risk assessment of West Nile (WNV) virus introduction into Barbados, West Indies. DESIGN AND METHODS: Three possible modes were considered: a) WNV infected mosquitoes via air transport, by city of departure, b) WNV infected mosquitoes via marine transport and c) viraemic migratory, birds. We estimated the number of WNV infected migratory birds as the product of the proportion of migratory birds infected and the number of migratory birds entering Barbados in three taxonomic groups. We further estimated the number of days these birds would be infectious as: [formula: see text]. We then estimated the number (#) of infectious mosquito-days for mosquitoes entering Barbados via air transport as: # infected mosquitoes = (total flights per week/city) x (duration of WNV season) x (number of Culex mosquitoes aboard each flight) x (Culex mosquito WNV infection prevalence) x (vector competence index) x (days infectious). The number of infected mosquitoes entering Barbados via marine transport was estimated using a similar expression as for air transport, except that the number of airplanes and mosquitoes/airplane were substituted with the # of sea containers during a 22-week mosquito season and # of mosquitoes/container. RESULTS: Migratory birds (approximately 69-101 infected birds/year) were associated with the highest introductory risk followed by mode (a) (approximately 2 infected mosquitoes/year) and mode (b) (0. 004 infected mosquitoes/year). CONCLUSIONS: Migratory birds and mosquitoes via air are imminent threats for virus introduction. Impending co-circulation of West Nile virus and four strains of dengue virus may present new challenges for public health.

OBJETIVO: Presentar una valoración del riesgo cuantitativa de la introducción del Virus del Nilo Occidental (VNO) en Barbados, West Indies. MÉTODOS E DISEÑO: Se consideraron tres posibles modos: a) mosquitos infectados con el VNO vía transporte aéreo, por ciudad de salida, b) mosquitos infectados con el VNO vía transporte marítimo, y c) aves migratorias virémicas. Calculamos el número de aves migratorias infectadas con el VNO como el producto de la proporción de aves migratorias infectadas por el número de aves migratorias que entran a Barbados en tres grupos taxonómicos. Luego calculamos el número de días en que estas aves serían infecciosas, de la forma siguiente:[fórmula: ver en el texto].Calculamos entonces el número de días-mosquito infeccioso para los mosquitos que entran en Barbados mediante transporte aéreo, como sigue: # mosquitos infectados = (vuelos totales por semana/ciudad) x (duración de la estación del VNO) x (número de mosquitos Culex a bordo de cada vuelo) x (prevalencia de infección con VNO por mosquito Culex) x (índice de competencia del vector) x (días infecciosos). El número de mosquitos infectados que entraron a Barbados por vía del transporte marítimo fue calculado usando una fórmula similar a la usada en relación con el transporte aéreo, excepto que el número de aeroplanos y mosquitos/ aeroplanos fueron sustituidos con el # de contenedores marítimos durante una temporada de mosquitos de 22 semanas y el # de mosquitos/contenedor RESULTADOS: Las aves migratorias ~ (69-101 aves infectadas/años) estuvieron asociadas con el riesgo de introducción más alto seguido del modo (a) (~2 mosquitos infectados/año), y finalmente el modo (b) (0.004 mosquitos infectados/año). CONCLUSIONES: Las aves migratorias y los mosquitos por vía aérea representan una amenaza inminente de introducción de virus. La co-circulación inminente del Virus del Nilo Occidental y cuatro cepas de virus de dengue pueden presentar nuevos desafíos a la salud pública.

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OBJECTIVE: To present a quantitative risk assessment of West Nile (WNV) virus introduction into Barbados, West Indies. DESIGN AND METHODS: Three possible modes were considered: a) WNV infected mosquitoes via air transport, by city of departure, b) WNV infected mosquitoes via marine transport and c) viraemic migratory, birds. We estimated the number of WNV infected migratory birds as the product of the proportion of migratory birds infected and the number of migratory birds entering Barbados in three taxonomic groups. We further estimated the number of days these birds would be infectious as: [formula: see text]. We then estimated the number (#) of infectious mosquito-days for mosquitoes entering Barbados via air transport as: # infected mosquitoes = (total flights per week/city) x (duration of WNV season) x (number of Culex mosquitoes aboard each flight) x (Culex mosquito WNV infection prevalence) x (vector competence index) x (days infectious). The number of infected mosquitoes entering Barbados via marine transport was estimated using a similar expression as for air transport, except that the number of airplanes and mosquitoes/airplane were substituted with the # of sea containers during a 22-week mosquito season and # of mosquitoes/container. RESULTS: Migratory birds (approximately 69-101 infected birds/year) were associated with the highest introductory risk followed by mode (a) (approximately 2 infected mosquitoes/year) and mode (b) (0. 004 infected mosquitoes/year). CONCLUSIONS: Migratory birds and mosquitoes via air are imminent threats for virus introduction. Impending co-circulation of West Nile virus and four strains of dengue virus may present new challenges for public health.

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Leptospirosis is a febrile zoonosis of worldwide distribution. A latex agglutination assay was evaluated in two studies, the first using a panel of well-characterized sera from patients with leptospirosis and from patients with other disease states and the second, a prospective hospital-based study, evaluating sera from 186 consecutive patients admitted to hospital with acute febrile illness. The confirmed leptospirosis serum panel included paired acute- and convalescent-phase specimens from 40 cases, of which 34 gave positive latex tests (case sensitivity, 85%; 95% confidence interval [95% CI], 70 to 94%). The other diseases represented in the panel of 112 specimens from nonleptospirosis patients included autoimmune diseases, brucellosis, dengue, melioidosis, malaria, syphilis, toxoplasmosis, viral hepatitis, and a number of other viral infections. The specificity of latex agglutination using this panel was 81% (95% CI, 73 to 87%). Among the patients with acute febrile illness, there were 25 cases of leptospirosis and 161 patients with other diagnoses. The sensitivity and specificity of latex agglutination in this group were 88% (95% CI, 72 to 97%) and 98% (95% CI, 95 to 100%), respectively. In this evaluation, the two distinct groups of specimens gave similar results for sensitivity, but specificity was different in each study. The sensitivity and specificity observed for the hospital study were similar to those obtained in evaluations of other rapid tests in the same population. The results of this study suggest that multiple evaluations of new diagnostic assays should be performed, because performance characteristics may vary in different populations.

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Type-specific enzyme-linked immunosorbent assays, based upon recombinant glycoprotein G (gG), were used to detect antibodies to HSV-1 and HSV-2, in a small Caribbean island population. A blinded serosurvey was performed on samples from 184 blood donors, 122 pregnant women, and 120 HIV-positive patients. The seroprevalence of HSV-1 and HSV-2 was 81% and 34%, respectively, in blood donors, 84% and 40% in the antenatal population and 89% and 77% in the HIV-positive group. As expected the majority of adults were seropositive against HSV-1. However, the HSV-2 seroprevalence was significantly higher in HIV-infected adults than in the other groups. These findings support the need for prospective epidemiological studies in this population.

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Human infection with the sheep nasal botfly Oestrus ovis occurs sporadically. In most cases, there is a history of a strike in the eye by the adult fly. Human O. ovis has been reported rarely from the Americas. We report the first case of O. ovis infection in the Caribbean region, which occurred in an urban area of Barbados. The patient responded to removal of the larvae from the conjunctiva and symptomatic treatment.

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Human infection with the sheep nasal botfly Oestrus ovis occurs sporadically. In most cases, there is a history of a strike in the eye by the adult fly. Human O. ovis has been reported rarely from the Americas. We report the first case of O. ovis infection in the Caribbean region, which occurred in an urban area of Barbados. The patient responded to removal of the larvae from the conjunctiva and symptomatic treatment

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Leptospirosis is a zoonotic disease, maintained by chronic infection of the kidneys of reservoir animals, usually small mammals. Infection in humans is acquired from direct or indirect exposure to the urine of infected animals. Leptospirosis has a high incidence in tropical regions, and has been studied extensively in several Caribbean countries. We studied the carriage of Leptospira serovars by two small mammals which are potential maintenance hosts of the disease in Barbados. A total of 136 mongooses (Herpestes auropunctatus) and 97 mice (Mus musculus) were caught in live traps. Leptospiral antibodies were detected by microscopic agglutination test (MAT) using antigens representing 12 serogroups, and kidney tissues were inoculated into polysorbate medium for isolation of leptospires. The seroprevalence (at a titre of > or = 100) in mice was 28.2% (24/85, 95% CI 19.0, 39.1) and in mongooses 40.7% (48/118, 95% CI 31.7, 50.1). In mice, antibodies were detected predominantly against serogroups Ballum and Autumnalis, while in mongooses the predominant serogroup was Autumnalis. Leptospires were isolated from 28 mice (28.9%, 95% CI 20.1, 39.0) and from 4 mongooses (2.9%, 95% CI 0.8, 7.4). Mouse isolates were identified as serovars arborea (17) and bim (7). As in other parts of the world, common house mice (Mus musculus) represent a significant reservoir of leptospirosis. Although carriage of the Ballum serovar, arborea, was not unexpected, this represents the first time that an animal reservoir of serovar bim has been identified. This is significant because bim causes about 63% of human leptospirosis in Barbados, and control efforts and education for prevention can now be targeted at a specific reservoir.

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Leptospirosis is a zoonotic disease, maintained by chronic infection of the kidneys of reservoir animals, usually small mammals. Infection in humans is acquired from direct or indirect exposure to the urine of infected animals. Leptospirosis has a high incidence in tropical regions, and has been studied extensively in several Caribbean countries. We studied the carriage of Leptospira serovars by two small mammals which are potential maintenance hosts of the disease in Barbados. A total of 136 mongooses (Herpestes auropunctatus) and 97 mice (Mus musculus) were caught in live traps. Leptospiral antibodies were detected by microscopic agglutination test (MAT) using antigens representing 12 serogroups, and kidney tissues were inoculated into polysorbate medium for isolation of leptospires. The seroprevalence (at a titre of > or = 100) in mice was 28.2 (24/85, 95 CI 19.0, 39.1) and in mongooses 40.7 (48/118, 95 CI 31.7, 50.1). In mice, antibodies were detected predominantly against serogroups Ballum and Autumnalis, while in mongooses the predominant serogroup was Autumnalis. Leptospires were isolated from 28 mice (28.9, 95 CI 20.1, 39.0) and from 4 mongooses (2.9, 95 CI 0.8, 7.4). Mouse isolates were identified as serovars arborea (17) and bim (7). As in other parts of the world, common house mice (Mus musculus) represent a significant reservoir of leptospirosis. Although carriage of the Ballum serovar, arborea, was not unexpected, this represents the first time that an animal reservoir of serovar bim has been identified. This is significant because bim causes about 63 of human leptospirosis in Barbados, and control efforts and education for prevention can now be targeted at a specific reservoir.

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Haemophilus influenzae is one of the common bacterial pathogens which affect children. Resistance to frequently used antibiotics is becoming a significant problem in community isolates of common pathogens. A retrospective review was conducted of the serotypes and antimicrobial sensitivity of H influenzae isolates from bacterial conjunctivitis, over an 18-month period. Data on antimicrobial sensitivity (obtained by the National Committee for Clinical Laboratory Standards disk diffusion method) and beta-lactamase production, and typing results, were analysed. Ninety-nine isolates were recovered, of which 87 were typed. Most isolates were recovered from children under one year of age. Ninety-three percent were unencapsulated and biotypes I and IV were most common. H influenzae type b was recovered only twice. beta-lactamase was produced by 41% isolates while four isolates were ampicillin-resistant but did not produce beta-lactamase. All isolates were sensitive to chloramphenicol and 45% were co-trimoxazole sensitive. H influenzae is commonly isolated from bacterial conjunctivitis in Barbados and, as elsewhere, the majority of isolates are from small children and are non-encapsulated. However, there is a high prevalence of beta-lactamase production, which may serve as a reservoir for transfer to more invasive encapsulated strains of H influenzae within the oropharyngeal flora.

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Leptospirosis is an emerging zoonosis caused by pathogenic spirochetes belonging to the genus Leptospira. An understanding of leptospiral protein expression regulation is needed to develop new immunoprotective and serodiagnostic strategies. We used the humoral immune response during human leptospirosis as a reporter of protein antigens expressed during infection. Qualitative and quantitative immunoblot analysis was performed using sera from 105 patients from Brazil and Barbados. Sera from patients with other diseases and healthy individuals were evaluated as controls. Seven proteins, p76, p62, p48, p45, p41, p37, and p32, were identified as targets of the humoral response during natural infection. In both acute and convalescent phases of illness, antibodies to lipopolysaccharide were predominantly immunoglobulin M (IgM) while antibodies to proteins were exclusively IgG. Anti-p32 reactivity had the greatest sensitivity and specificity: positive reactions were observed in 37 and 84% of acute- and convalescent-phase sera, respectively, while only 5% of community control individuals demonstrated positive reactions. Six immunodominant antigens were expressed by all pathogenic leptospiral strains tested; only p37 was inconsistently expressed. Two-dimensional immunoblots identified four of the seven infection-associated antigens as being previously characterized proteins: LipL32 (the major outer membrane lipoprotein), LipL41 (a surface-exposed outer membrane lipoprotein), and heat shock proteins GroEL and DnaK. Fractionation studies demonstrated LipL32 and LipL41 reactivity in the outer membrane fraction and GroEL and DnaK in the cytoplasmic fraction, while p37 appeared to be a soluble periplasmic protein. Most of the other immunodominant proteins, including p48 and p45, were localized to the inner membrane. These findings indicate that leptospiral proteins recognized during natural infection are potentially useful for serodiagnosis and may serve as targets for vaccine design.

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The susceptibility of 39 toxin producing Clostridium difficile isolates from stools of hospitalized patients was determined, by disc diffusion, to six antibiotics. All but one isolate (toxin A negative) produced toxin A and toxin B. A wide variation in susceptibility to clindamycin, tetracycline and chloramphenicol was noted. Erythromycin and cotrimoxazole showed a clear-cut discrimination in resistance and susceptibility, while all isolates were sensitive to vancomycin. Erythromycin sensitive isolates demonstrated a significant association with diarrhoea (60.9%, 14/23, p < 0.001). These strains were predominantly found at the University Hospital of the West Indies (UHWI, 94.1%, 16/17). Strains resistant to erythromycin and clindamycin together were commonly found at the National Chest Hospital (NCH, 68.2%, 15/22). All erythromycin sensitive strains found at the NCH were from patients transferred to that hospital. These findings suggest that there is a common strain of C difficile (erythromycin resistant) at the NCH different from that found at the UHWI; the resistant pattern seen with isolates from the NCH was typical of toxigenic serogroup C strain and could be typed by the the disc diffusion method. Patients at the NCH who were colonized with either of the two strains of C difficile were likely to get diarrhoea, once there was suppression of the normal microflora by antibiotics and colonic overgrowth with C difficile.

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Haemophilus influenzae is one of the common bacterial pathogens which affect children. Resistance to frequently used antibiotics is becoming a significant problem in community isolates of common pathogens. A retrospective review was conducted of the serotypes and antimicrobial sensitivity of H influenzae isolates from bacterial conjunctivitis, over an 18-month period. Data on antimicrobial sensitivity (obtained by the National Committee for Clinical Laboratory Standards disk diffusion method) and beta-lactamase production, and typing results, were analysed. Ninety-nine isolates were recovered, of which 87 were typed. Most isolates were recovered from children under one year of age. Ninety-three percent were unencapsulated and biotypes I and IV were most common. H influenzae type b was recovered only twice. beta-lactamase was produced by 41 isolates while four isolates were ampicillin-resistant but did not produce beta-lactamase. All isolates were sensitive to chloramphenicol and 45 were co-trimoxazole sensitive. H influenzae is commonly isolated from bacterial conjunctivitis in Barbados and, as elsewhere, the majority of isolates are from small children and are non-encapsulated. However, there is a high prevalence of beta-lactamase production, which may serve as a reservoir for transfer to more invasive encapsulated strains of H influenzae within the oropharyngeal flora.

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Leptospirosis is a worldwide zoonotic infection with a much greater incidence in tropical regions and has now been identified as one of the emerging infectious diseases. The epidemiology of leptospirosis has been modified by changes in animal husbandry, climate, and human behavior. Resurgent interest in leptospirosis has resulted from large outbreaks that have received significant publicity. The development of simpler, rapid assays for diagnosis has been based largely on the recognition that early initiation of antibiotic therapy is important in acute disease but also on the need for assays which can be used more widely. In this review, the complex taxonomy of leptospires, previously based on serology and recently modified by a genotypic classification, is discussed, and the clinical and epidemiological value of molecular diagnosis and typing is also evaluated.

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Leptospirosis is a common and underdiagnosed zoonosis. Two rapid assays for serological diagnosis of acute leptospirosis in diagnostic laboratories, the immunoglobulin M (IgM)-dipstick assay and the indirect hemagglutination assay (IHA), were evaluated and compared with standard assays. Sera were examined from 104 patients admitted to a hospital for investigation in a leptospirosis diagnostic protocol. Specimens for serology were taken on days 1 and 4 of the patients' hospital stay. Antibodies were detected using an IgM-enzyme-linked immunosorbent assay (ELISA), microscopic agglutination test (MAT), an IgM-dipstick assay, and an IHA. Fifty-one patients were found to have leptospirosis. The sensitivity of the IgM-dipstick assay was 98%, its specificity was 90.6%, its positive predictive value was 90.9%, and its negative predictive value was 98%. The sensitivity of the IHA was 92.2%, its specificity was 94.4%, its positive predictive value was 95.9%, and its negative predictive value was 92.7%. The standard IgM-ELISA and MAT, were positive in the first samples tested from 67 and 55% of the cases, respectively, and the rapid IgM-dipstick assay and IHA were positive in 71 and 49%, respectively, in the first sample tested. Both rapid assays are highly sensitive and specific. Neither requires specialized equipment, and both are suitable for use in diagnostic laboratories.

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The susceptibility of 39 toxin producing Clostridium difficile isolates from stools of hospitalized patients was determined, by disc diffusion, to six antibiotics. All but one isolate (toxin A negative) produced toxin A and toxin B. A wide variation in susceptibility to clindamycin, tetracycline and chloramphenicol was noted. Erythromycin and cotrimoxazole showed a clear-cut discrimination in resistance and susceptibility, while all isolates were sensitive to vancomycin. Erythromycin sensitive isolates demonstrated a significant association with diarrhoea (60.9, 14/23, p < 0.001). These strains were predominantly found at the University Hospital of the West Indies (UHWI, 94.1, 16/17). Strains resistant to erythromycin and clindamycin together were commonly found at the National Chest Hospital (NCH, 68.2, 15/22). All erythromycin sensitive strains found at the NCH were from patients transferred to that hospital. These findings suggest that there is a common strain of C difficile (erythromycin resistant) at the NCH different from that found at the UHWI; the resistant pattern seen with isolates from the NCH was typical of toxigenic serogroup C strain and could be typed by the the disc diffusion method. Patients at the NCH who were colonized with either of the two strains of C difficile were likely to get diarrhoea, once there was suppression of the normal microflora by antibiotics and colonic overgrowth with C difficile.

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Genetic heterogeneity has been proposed as a hallmark feature of allergic disease. To test the hypothesis that total IgE levels are jointly influenced by a locus on chromosome 12q21.1-q21.31 and a locus on 17q11.2-q21.2, we conducted multipoint allele-sharing analyses using nonparametric linkage (NPL) methods on Afro-Caribbean families from Barbados to test for evidence of gene-gene interactions. Significant correlations were observed between NPL scores at D12S1052 and both D17S1293 and D17S1299 for a dichotomized phenotype of total IgE. An analysis of family-specific NPL scores revealed that evidence for interaction was being driven largely by one multiplex pedigree (NPL = 12.01, 12.23, and 12.16 at D12S1052, D17S1293, and D17S1299, respectively). Using the programs SIMWALK (v2.0) and GOLD, a different set of haplotypes in this influential family was observed around D12S1052 and the 17q loci compared to the other Barbados pedigrees. Our findings are a classic example of founder effect, provide evidence for sensitivity of this type of linkage analysis to unusual pedigrees, and highlight an element of genetic heterogeneity that has been given little attention in the study of complex traits.

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The persistence of anti-leptospiral IgM and IgG antibodies and agglutinating antibodies was studied in serologically confirmed cases of severe leptospirosis during the acute illness and over periods of several years after recovery. The antibody response in non-leptospirosis patients presenting to hospital with similar symptoms over the same period of time was used to estimate the background antibody level to leptospirosis in the community. All patients enrolled in the study had blood samples collected twice in the acute stage of illness, once during convalescence and then annually from the time of initial hospitalisation until the end of the study period. Six hundred and thirty-eight patients presented to hospital with acute febrile illness, of whom 321 were diagnosed with leptospirosis. Patients who had severe leptospirosis commonly remained seropositive, with IgM, IgG and agglutinating antibodies detectable for several years after infection. A significant proportion of cases had high titres of agglutinating antibody detectable by the microscopic agglutination test (> or = 800). There were marked differences in the magnitude and duration of persistence of agglutinating antibodies directed against different serogroups. More than 20% of cases with evidence of infection with serogroup Autumnalis retained titres of >800, 4 years after the acute illness. In one case a titre of 800 was detected 11 years after infection. Persistence of agglutinating antibody titres can create problems in interpretation of serological results and make it impossible to estimate the time of infection, given a specific titre. This study demonstrates that in endemic areas where seroprevalence is high, use of a single elevated titre is not reliable to define a current infection.

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