RESUMEN
We assessed the prevalence of three common hereditary blood disorders (sickle-cell and beta-thalassaemia traits and glucose 6-phosphate dehydrogenase deficiency) among the Omani population. We interviewed a representative sample of 6103 Omani households and blood samples from 6342 children aged 0-5 years were collected. About 27% of Omani males had inherited glucose-6-phosphate dehydrogenase deficiency (compared with 11% of females) while countrywide prevalence rates for the sickle-cell and beta-thalassaemia traits were estimated to be 5.8% and 2.2% respectively and showed no significant gender differences. There was a significant association between all three disorders and region of the country.
Asunto(s)
Anemia de Células Falciformes/epidemiología , Deficiencia de Glucosafosfato Deshidrogenasa/epidemiología , Talasemia beta/epidemiología , Anemia de Células Falciformes/diagnóstico , Anemia de Células Falciformes/genética , Preescolar , Consanguinidad , Femenino , Deficiencia de Glucosafosfato Deshidrogenasa/diagnóstico , Deficiencia de Glucosafosfato Deshidrogenasa/genética , Encuestas Epidemiológicas , Humanos , Lactante , Masculino , Tamizaje Masivo , Omán/epidemiología , Vigilancia de la Población , Prevalencia , Características de la Residencia/estadística & datos numéricos , Factores de Riesgo , Arabia Saudita/epidemiología , Distribución por Sexo , Encuestas y Cuestionarios , Emiratos Árabes Unidos/epidemiología , Talasemia beta/diagnóstico , Talasemia beta/genéticaRESUMEN
We assessed the prevalence of three common hereditary blood disorders [sickle-cell and beta-thalassaemia traits and glucose 6-phosphate dehydrogenase deficiency] among the Omani population. We interviewed a representative sample of 6103 Omani households and blood samples from 6342 children aged 0-5 years were collected. About 27% of Omani males had inherited glucose-6-phosphate dehydrogenase deficiency [compared with 11% of females] while countrywide prevalence rates for the sickle-cell and beta-thalassaemia traits were estimated to be 5.8% and 2.2% respectively and showed no significant gender differences. There was a significant association between all three disorders and region of the country
Asunto(s)
Anemia de Células Falciformes , Preescolar , Deficiencia de Glucosafosfato Deshidrogenasa , Encuestas Epidemiológicas , Tamizaje Masivo , Prevalencia , Encuestas y Cuestionarios , Características de la Residencia , Factores de Riesgo , Distribución por Sexo , Talasemia betaRESUMEN
BACKGROUND: The immunogenicity of oral poliovirus vaccine (OPV), particularly the type 3 component, is lower in infants in most developing countries than in infants in industrialized countries. We conducted a multicenter trial in Oman to evaluate the response to a supplemental dose of four poliovirus vaccine formulations. METHODS: At nine months of age, infants were randomly assigned to receive inactivated-poliovirus vaccine (IPV), administered subcutaneously; trivalent OPV manufactured in the United States or in Europe; or monovalent type 3 OPV. Serum samples were collected at enrollment and 7 and 30 days later. All of the infants had previously received five doses of OPV. RESULTS: We enrolled 1025 infants; 785 (76.6 percent) met all the study requirements. At enrollment, 96.8 percent of the infants were seropositive for poliovirus type 1, 98.0 percent for type 2, and 88.0 percent for type 3. At 30 days there were no significant increases in type 3 seroprevalence or in the median antibody titer in the groups of infants who received OPV. Among the recipients of IPV, type 3 seroprevalence increased from 87.8 percent at enrollment to 97.1 percent at 30 days (P<0.001), and the median antibody titer increased from 1:228 to 1:1448 or higher (P<0.001). The rapid initial increase in the antibody titer suggests a secondary immune response. CONCLUSIONS: A supplemental dose of IPV has excellent immunogenicity and leads to increases in the titer of antibodies against type 3 poliovirus, whereas supplemental doses of the oral vaccines do not have these effects.
Asunto(s)
Anticuerpos Antivirales/sangre , Poliomielitis/inmunología , Vacuna Antipolio de Virus Inactivados/inmunología , Vacuna Antipolio Oral/inmunología , Poliovirus/inmunología , Países en Desarrollo , Heces/virología , Femenino , Humanos , Inmunización Secundaria , Lactante , Masculino , Omán , Poliomielitis/prevención & control , Poliovirus/clasificación , Poliovirus/aislamiento & purificación , Vacuna Antipolio de Virus Inactivados/administración & dosificación , Vacuna Antipolio Oral/administración & dosificación , Estudios SeroepidemiológicosRESUMEN
In 1995 and 1996, 4 persons from the Sultanate of Oman were confirmed with clinical Crimean-Congo haemorrhagic fever (CCHF). To assess the prevalence of CCHF virus infection in Oman, a convenience sample of imported and domestic animals from farms, abattoirs and livestock markets was examined by enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) antibodies to CCHF virus. Ticks were collected from selected animals, identified, pooled by species, host and location and tested for evidence of infection with CCHF virus by antigen-capture ELISA. Serum samples from individuals working in animal and nonanimal contact-related jobs were also tested for CCHF antibodies. Serological evidence of infection was noted in 108 (22%) of 489 animals. Most of the ticks collected (618 of 912) from all species of sampled livestock were Hyalomma anatolicum anatolicum, a competent vector and reservoir of CCHF virus. 243 tick pools were tested for CCHF antigen, and 19 pools were positive. Of the individuals working in animal contact-related jobs, 73 (30.3%) of 241 non-Omani citizens and only 1 (2.4%) of 41 Omani citizens were CCHF antibody-positive. Butchers were more likely to have CCHF antibody than persons in other job categories. The presence of clinical disease and the serological results for animals and humans and infected Hyalomma ticks provide ample evidence of the presence of CCHF virus in yet another country in the Arabian Peninsula.
Asunto(s)
Animales Domésticos , Anticuerpos Antivirales/sangre , Virus de la Fiebre Hemorrágica de Crimea-Congo/inmunología , Virus de la Fiebre Hemorrágica de Crimea-Congo/aislamiento & purificación , Fiebre Hemorrágica de Crimea/epidemiología , Fiebre Hemorrágica de Crimea/veterinaria , Garrapatas/virología , Adolescente , Adulto , Anciano , Animales , Animales Domésticos/inmunología , Antígenos Virales/análisis , Vectores Arácnidos/virología , Ensayo de Inmunoadsorción Enzimática , Humanos , Inmunoglobulina G/sangre , Masculino , Persona de Mediana Edad , Enfermedades Profesionales/epidemiología , Omán/epidemiología , Prevalencia , Sensibilidad y Especificidad , Estudios Seroepidemiológicos , Ovinos , Enfermedades de las Ovejas/epidemiología , Infestaciones por Garrapatas/epidemiología , Infestaciones por Garrapatas/veterinariaRESUMEN
Oman is generally hot and dry, but the Salalah region in southern Dhofar province is relatively cool and rainy during the summer monsoon, and has a distinctive pattern of infection. Important, notifiable infections in Oman include tuberculosis, brucellosis (endemic in Dhofar), acute gastroenteritis, and viral hepatitis: 4.9% of the adults are seropositive for hepatitis B surface antigen and approximately 1.2% for hepatitis C virus. Infection with human immunodeficiency virus is uncommon, and leprosy, rabies, and Crimean-Congo hemorrhagic fever are rare. Between 1990 and 1998, the incidence of malaria, (>70% due to Plasmodium falciparum) decreased from 32,700 to 882 cases. Cutaneous and visceral leishmaniasis (caused by Leishmania tropica and L. infantum, respectively) and Bancroftian filariasis occur sporadically. Intestinal parasitism ranges from 17% to 42% in different populations. A solitary focus of schistosomiasis mansoni in Dhofar has been eradicated. There are major programs for the elimination of tuberculosis, leprosy, and malaria, and to control brucellosis, leishmaniasis, sexually transmitted diseases, trachoma, acute respiratory infection in children, and diarrheal diseases. The Expanded Program on Immunization was introduced in 1981: diphtheria, neonatal tetanus, and probably poliomyelitis have been eliminated.
Asunto(s)
Enfermedades Transmisibles/epidemiología , Medicina Tropical/estadística & datos numéricos , Humanos , Omán/epidemiologíaRESUMEN
Seroprevalence and geometric mean titers (GMTs) were compared at 6 and 10 months after vaccination with monovalent type 1 oral poliovirus vaccine (OPV) at 6 months and trivalent OPV at 7 and 9 months. Group 1 had received 4 doses of OPV, group 2 OPV at birth and 3 doses of OPV and inactivated poliovirus vaccine (IPV), and group 3 placebo at birth and 3 doses of IPV. A total of 547 infants completed the study. At 10 months, seroprevalence to poliovirus type 1 was 98%, 99%, and 98% in groups 1, 2, and 3; 100%, 100%, and 98% to poliovirus type 2; and 80%, 96%, and 91% to poliovirus type 3. Differences in seroprevalence among the groups were significant for poliovirus type 3 (P < .001). Between 6 and 10 months, significant increases in seroprevalence and GMTs occurred for poliovirus type 1 but not for types 2 and 3. Two OPV doses following 3 IPV doses did not significantly increase seroprevalence or raise GMTs for poliovirus types 2 and 3; however, significant increases were found for poliovirus type 1, which may have benefitted from monovalent type 1 administration.
Asunto(s)
Poliomielitis/prevención & control , Vacuna Antipolio de Virus Inactivados/administración & dosificación , Vacuna Antipolio Oral/administración & dosificación , Poliovirus/inmunología , Anticuerpos Antivirales/aislamiento & purificación , Humanos , Esquemas de Inmunización , Recién Nacido , Omán , Poliomielitis/inmunología , Vacuna Antipolio de Virus Inactivados/inmunología , Vacuna Antipolio Oral/inmunologíaRESUMEN
Countries are increasingly requesting guidance on carrying out acute flaccid paralysis (AFP) surveillance, aimed at detecting and confirming all cases of acute paralytic poliomyelitis. The experience of Oman provides many lessons in this respect. AFP surveillance in Oman was established systematically. First, an epidemiologist was assigned to coordinate surveillance, and a laboratory for performing polio-virus isolation was identified. Next, operational guidelines for AFP surveillance were developed and widely promoted among health staff. The quality of the system has been monitored for more than 3 years with selected performance indicators. From January 1990 to April 1993, 49 AFP cases were reported, corresponding to an average annual rate of 2.1 AFP cases per 100,000 children aged less than 15 years. A total of 98% of the AFP cases were investigated within 48 hours of being reported; two stool samples were obtained from 94% of the cases. Following complete investigation, nearly a third of the reported AFP cases were classified as being clinically compatible with Guillain-Barré syndrome. Four AFP cases, all reported in 1991, were confirmed to be due to wild type 3 poliovirus. Because AFP surveillance detected these cases rapidly, Oman was able to carry out outbreak control measures promptly and more than 350,000 extra doses of oral poliovirus vaccine were delivered to children under 6 years of age.
Asunto(s)
Brotes de Enfermedades , Poliomielitis/epidemiología , Adolescente , Niño , Preescolar , Humanos , Lactante , Recién Nacido , Hipotonía Muscular , Omán/epidemiología , Parálisis/epidemiología , Parálisis/etiología , Poliomielitis/prevención & control , Poliomielitis/virología , Poliovirus/aislamiento & purificación , Vacuna Antipolio Oral , Vigilancia de la PoblaciónRESUMEN
Variation in attack rates of paralytic disease by region during the 1988-1989 epidemic of type 1 poliomyelitis in Oman provided the stimulus to test the hypothesis that these observations were due to regional differences in the response of infants to trivalent oral poliovirus vaccine (OPV). Seroprevalence studies of 394 children born during the outbreak were conducted in six different regions of Oman and in two socioeconomic status (SES) groups in the capital city of Muscat; a seroconversion study was also carried out in 105 infants born after the outbreak. Seroprevalence rates by region after receipt of at least three doses of OPV ranged from 90% to 100% (median 94%) to poliovirus type 1, and from 86% to 100% (median 97%) to type 2, and from 47% to 79% (median 72%) to type 3, with the lowest rates observed in regions with the highest incidence of type 1 paralytic disease. In Muscat, seroprevalence rates were also significantly lower in low versus high SES groups (type 1: 84% versus 98%, respectively [P = 0.006]; type 3: 59% versus 86%, respectively [P = 0.001]). In the seroconversion study conducted after the outbreak, 89%, 100% and 50% of infants had detectable antibodies to types 1, 2, and 3, respectively, after four doses of OPV. Low responses to type 3 were also associated with the occurrence of sporadic cases of type 3 poliomyelitis in 1991, in spite of high rates of coverage with at least four doses of OPV (> 96%) throughout the country.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Anticuerpos Antivirales/inmunología , Brotes de Enfermedades , Poliomielitis/epidemiología , Vacuna Antipolio Oral , Poliovirus/inmunología , Formación de Anticuerpos , Humanos , Lactante , Recién Nacido , Omán/epidemiología , Poliomielitis/prevención & control , Vigilancia de la Población , Prevalencia , Estudios SeroepidemiológicosRESUMEN
Although injections administered during the incubation period of wild poliovirus infection have been associated with an increased risk of paralytic poliomyelitis, quantitative estimates of the risk have not been established. During a poliomyelitis outbreak investigation in Oman, vaccination records were reviewed for 70 children aged 5-24 months with poliomyelitis and from 692 matched control children. A significantly higher proportion of cases received a DTP (diphtheria and tetanus toxoids and pertussis vaccine) injection within 30 days before paralysis onset than did controls (42.9% vs. 28.3%; odds ratio, 2.4; 95% confidence interval, 1.3-4.2). The proportion of poliomyelitis cases that may have been provoked by DTP injections was 35% for children 5-11 months old. This study confirms that injections are an important cause of provocative poliomyelitis. Although the benefits of DTP vaccination should outweigh the risk of subsequent paralysis, these data stress the importance of avoiding unnecessary injections during outbreaks of wild poliovirus infection.