Community Foodborne of Salmonella Weltevreden Outbreak at Northern Governorate, Sultanate of Oman.

OBJECTIVES: To investigate the course of a community gastroenteritis outbreak by Salmonella and implement interventional activities and roles to prevent occurring such an outbreak in the future. METHODS: From August 27 to 2 September 2015, 101 individuals were reported among a local community. All affected individuals had a history of food consumption at a local restaurant. A rapid response team conducted active surveillance and interview with the affected individuals and workers of the restaurant. Food items and stools from food handlers and affected individuals were cultured and sent for genotyping. An environmental audit of the restaurant had been conducted. RESULTS: The total majority of the affected individuals were male and more than 70% belonged to the young age group from 15 to 45 years. Out of the total, 97% had diarrhea, 70% fever, 56% abdominal cramps and 49% vomiting. All those affected were managed symptomatically except for 14 cases admitted for intravenous rehydration. Breakdown of food safety and basic personal hygiene were detected in the environment of the restaurant and among the workers. There are 39 out of 49 stool cultures of cases, six out of 18 food handlers, and five food samples were positive for Salmonella spp. The identical DNA fingerprinting pattern among S. Weltevreden strains originating from human cases and food was detected. CONCLUSION: This is the first reported community foodborne of S. Weltevreden outbreak in Oman. The importance of food safety and rigors environmental safety is emphasized. Basic personal hygiene and training of food handlers in restaurants are recommended with public health measurements.

Clinical and molecular epidemiology of Crimean-Congo hemorrhagic fever in Oman.

BACKGROUND: Crimean-Congo hemorrhagic fever (CCHF) is a serious disease with a high fatality rate reported in many countries. The first case of CCHF in Oman was detected in 1995 and serosurveys have suggested widespread infection of humans and livestock throughout the country. METHODOLOGY: Cases of CCHF reported to the Ministry of Health (MoH) of Oman between 1995 and 2017 were retrospectively reviewed. Diagnosis was confirmed by serology and/or molecular tests in Oman. Stored RNA from recent cases was studied by sequencing the complete open reading frame (ORF) of the viral S segment at Public Health England, enabling phylogenetic comparisons to be made with other S segments of strains obtained from the region. FINDINGS: Of 88 cases of CCHF, 4 were sporadic in 1995 and 1996, then none were detected until 2011. From 2011-2017, incidence has steadily increased and 19 (23.8%) of 80 cases clustered around Eid Al Adha. The median (range) age was 33 (15-68) years and 79 (90%) were male. The major risk for infection was contact with animals and/or butchering in 73/88 (83%) and only one case was related to tick bites alone. Severe cases were over-represented: 64 (72.7%) had a platelet count < 50 x 109/L and 32 (36.4%) died. There was no intrafamilial spread or healthcare-associated infection. The viral S segments from 11 patients presenting in 2013 and 2014 were all grouped in Asia 1 (IV) lineage. CONCLUSIONS: CCHF is well-established throughout Oman, with a single strain of virus present for at least 20 years. Most patients are men involved in animal husbandry and butchery. The high mortality suggests that there is substantial under-diagnosis of milder cases. Preventive measures have been introduced to reduce risks of transmission to animal handlers and butchers and to maintain safety in healthcare settings.

Epidemiology of Meningitis in Oman-Implications for Future Surveillance.

OBJECTIVES: This study aimed to understand the epidemiology of meningitis cases admitted to hospitals in Oman and to identify any changing microbial patterns from the introduction of the new vaccines. METHODS: A retrospective analysis of all cases of meningitis reported through a national surveillance system. Meningitis is a notifiable disease. RESULTS: Of a total of 581 cases of meningitis from the period between January 1, 2005 and December 31, 2013, 15% (88) were confirmed to be bacterial in origin and 7.2% (42/581) viral. In 50.9% (296) of patients with suspected pyogenic meningitis, no specific bacterial pathogen were identified, and in 26% of cases (151) a cerebrospinal fluid study could not be undertaken. Among 88 cases with confirmed bacterial pathogens the organisms identified were Streptococcus pneumoniae (65.9%), Neisseria meningitides (18.2%), Haemophilus influenzae (6.8%), and other organisms (9.1%). The peak incidence was in children <2 years of age (39.4%). It showed notable decline in H. influenzae cases as well as pneumococcal meningitis cases, possibly indicative of the successful immunization program. CONCLUSION: A drop in H. Influenzae and pneumococcal meningitis cases was possibly the effect of the introduction of vaccines. It shows the need for improving diagnostic accuracy, laboratory capacities, and quality of surveillance reporting.

Incidence and economic burden of acute otitis media in children aged up to 5years in three Middle Eastern countries and Pakistan: A multinational, retrospective, observational study.

Epidemiological data on acute otitis media (AOM), an infectious disease frequently affecting children, are lacking in some countries. This study was undertaken to assess the incidence of AOM in children ≤5years in Saudi Arabia, Oman, Pakistan, and Turkey, as well as the economic burden from a parent/caregiver perspective. Medical records of 4043 children (Saudi Arabia=1023, Oman=998, Pakistan=1022, Turkey=1000) were retrospectively reviewed and the incidence of AOM episodes calculated from suspected and confirmed cases. Using a standardized Health Economics Questionnaire, parents recorded resource use and expenses incurred per AOM episode [in local currency and converted to US dollars (USD)]. The overall incidence of AOM episodes per 1000 person-years was: Saudi Arabia, 207 [95% confidence interval (CI): 178-238]; Oman, 105 (95% CI: 85-127); Pakistan, 138 (95% CI: 116-163); and Turkey, 99 (95% CI: 79-123). The mean total out-of-pocket healthcare expense incurred by parents/caregivers per episode was: Saudi Arabia USD67.1 [standard deviation (SD)=93.0], Oman USD16.1 (SD=16.4), Pakistan USD22.1 (SD=20.5), and Turkey USD33.6 (SD=44.9). The incidence of AOM episodes varied across all four countries, probably due to different diagnostic and management practices. Nevertheless, our results confirm that AOM causes a substantial burden to public health, reinforcing the need for cost-effective prevention strategies.

The Burden of Influenza-Associated Hospitalizations in Oman, January 2008-June 2013.

INTRODUCTION: Acute respiratory infections (ARI), including influenza, comprise a leading cause of morbidity and mortality worldwide. Influenza surveillance provides important information to inform policy on influenza control and vaccination. While the epidemiology of influenza has been well characterized in western countries, few data exist on influenza epidemiology in the Eastern Mediterranean Region. We describe the epidemiology of influenza virus in Oman. METHODS: Using syndromic case definitions and protocols, patients from four regional hospitals in Oman were enrolled in a descriptive prospective study to characterize the burden of severe acute respiratory infections (SARI) and influenza. Eligible patients provided demographic information as well as oropharyngeal (OP) and nasopharyngeal (NP) swabs. Specimens were tested for influenza A and influenza B; influenza A viruses were subtyped using RT-PCR. RESULTS: From January 2008 through June 2013, a total of 5,147 cases were enrolled and tested for influenza. Influenza strains were detected in 8% of cases for whom samples were available. Annual incidence rates ranged from 0.5 to 15.4 cases of influenza-associated SARI per 100,000 population. The median age of influenza patients was 6 years with children 0-2 years accounting for 34% of all influenza-associated hospitalizations. By contrast, the median age of non-influenza SARI cases was 1 year with children 0-2 years comprising 59% of SARI. Compared to non-influenza SARI cases, a greater proportion of influenza cases had pre-existing chronic conditions and underwent ventilation during hospitalization. CONCLUSIONS: Influenza virus is associated with a substantial proportion of SARI in Oman. Influenza in Oman approximately follows northern hemisphere seasonality, with major peaks in October to December and a lesser peak around April. The burden of influenza was greatest in children and the elderly. Future efforts should examine the burden of influenza in other potential risk groups such as pregnant women to inform interventions including targeted vaccination.

Dengue epidemiological trend in Oman: a 13-year national surveillance and strategic proposition of imported cases.

Dengue fever has emerged as a major public health problem globally in the past three decades. A 13-year national surveillance data analysis was done to describe the epidemiology and its trend of dengue disease in Oman reported between 2001 and 2013. Laboratory-confirmed dengue virus infections reported were studied retrospectively during the study period. A total of 64 laboratory confirmed cases were reported. All the patients contracted the disease during their visit to South-East Asian countries, hence classified as imported cases. The majority of the cases were reported in the year 2012 (23.4%). The most important clinical characteristics were fever (90.6%), myalgia (35.9%) and rash/petechial rash (20.3%). Thrombocytopenia was seen in 31.2% of the study subjects. The mortality was nearly 4.6% and all other patients made a full recovery. The most effective measure for travellers is taking precautions to avoid mosquito bites.

Progress toward elimination of hepatitis B virus transmission in Oman: impact of hepatitis B vaccination.

Approximately 2-7% of the Omani population has chronic hepatitis B virus (HBV) infection. To decrease this burden, universal childhood hepatitis B vaccination was introduced in Oman in 1990. The hepatitis B vaccination strategy and reported coverage were reviewed. To assess the impact of the program on chronic HBV seroprevalence, a nationally representative seroprevalence study was conducted in Oman in 2005. Since 1991, hepatitis B vaccination in Oman has reached almost every eligible child, with reported coverage of ≥ 97% for the birth dose and ≥ 94% for three doses. Of 175 children born pre-vaccine introduction, 16 (9.1%) had evidence of HBV exposure, and 4 (2.3%) had evidence of chronic infection. Of 1,890 children born after vaccine introduction, 43 (2.3%) had evidence of HBV exposure, and 10 (0.5%) had evidence of chronic infection. Oman has a strong infant hepatitis B vaccination program, resulting in a dramatic decrease in chronic HBV seroprevalence.

Fractional doses of inactivated poliovirus vaccine in Oman.

BACKGROUND: We conducted a clinical trial of fractional doses of inactivated poliovirus vaccine administered to infants in Oman, in order to evaluate strategies for making the vaccine affordable for use in developing countries. METHODS: We compared fractional doses of inactivated poliovirus vaccine (0.1 ml, representing one fifth of a full dose) given intradermally with the use of a needle-free jet injector device, with full doses of vaccine given intramuscularly, with respect to immunogenicity and reactogenicity. Infants were randomly assigned at birth to receive either a fractional dose or a full dose of inactivated poliovirus vaccine at 2, 4, and 6 months. We also administered a challenge dose of monovalent type 1 oral poliovirus vaccine at 7 months and collected stool samples before and 7 days after administration of the challenge dose. RESULTS: A total of 400 infants were randomized, of whom 373 (93.2%) fulfilled the study requirements. No significant baseline differences between the groups were detected. Thirty days after completion of the three-dose schedule, the rates of seroconversion to types 1, 2, and 3 poliovirus were 97.3%, 95.7%, and 97.9%, respectively, in the fractional-dose group, as compared with 100% seroconversion to all serotypes in the full-dose group (P=0.01 for the comparison with respect to type 2 poliovirus; results with respect to types 1 and 3 poliovirus were not significant). The median titers were significantly lower in the fractional-dose group than in the full-dose group (P<0.001 for all three poliovirus serotypes). At 7 months, 74.8% of the infants in the fractional-dose group and 63.1% of those in full-dose group excreted type 1 poliovirus (P=0.03). Between birth and 7 months, 42 hospitalizations were reported, all related to infectious causes, anemia, or falls, with no significant difference between vaccination groups. CONCLUSIONS: These data show that fractional doses of inactivated poliovirus vaccine administered intradermally at 2, 4, and 6 months, as compared with full doses of inactivated poliovirus vaccine given intramuscularly on the same schedule, induce similar levels of seroconversion but significantly lower titers. (Current Controlled Trials number, ISRCTN17418767.)

Acute bacterial meningitis among children < 5 years of age in Oman: a retrospective study during 2000-2005.

BACKGROUND: During the last two decades, significant changes have taken place in the epidemiology of meningitis, especially due to the global availability and expanding use of Hib vaccines. The introduction of conjugate Hib vaccine in the Expanded Programme of Immunization (EPI) in Oman and recent availability of meningococcal vaccines against serogroups A and C plus the introduction of pneumococcal heptavalent conjugate vaccine are expected to influence the epidemiology of the disease in the country. We conducted this periodic review of acute bacterial meningitis in children younger than five years of age in Oman from January 2000 to December 2005 to reflect changes in the epidemiological pattern of these pathogens. METHODOLOGY: Retrospective analysis of all cases of acute bacterial meningitis in children younger than five years of age reported to the Department of Communicable Diseases Surveillance and Control, Ministry of Health, Oman. RESULTS: There were 344 cases of meningitis due to suspected bacterial etiologies reported in children younger than 5 years of age. Although Haemophilus influenzae 76 (22%) was the most common pathogen identified during the study period, the incidence of meningitis due to Haemophilus influenzae has been dramatically reduced since the introduction of conjugate Hib vaccination in Oman in October 2001. Streptococcus pneumoniae 53 (15%) and Neisseria meningitidis 37 (11%) were the next two leading agents of meningitis respectively. In one hundred seventy four (52%) cases of presumptive bacterial meningitis, the etiologic organism remains unidentified. The peak occurrence of meningitis was in young children younger than one year old. The total male to female ratio was 1.4:1 and the case fatality rate (7 deaths) was 2%. CONCLUSIONS: With the introduction of Hib vaccine in Oman in October 2001, the absolute number of cases due to Haemophilus influenzae significantly declined over the years. The incidence of meningitis due to other pathogens such as S. pneumoniae and N. meningitidis remains steady. There is significant need to improve laboratory methods of bacterial detection and identification, which will help to formulate better antibiotic policies and strengthen control measures through newly introduced vaccines in Oman.

Costs of congenital rubella syndrome (CRS) in Oman: evidence based on long-term follow-up of 43 children.

As part of the national plan for elimination of rubella and congenital rubella syndrome (CRS), Oman established a national registry of CRS cases. As of May 2005, the registry included 43 surviving CRS cases, with a mean age of 11.9 years. Clinical examinations found that 84% had ocular defects, 84% had auditory/speech defects, 70% had neurological manifestations, and 42% had cardiac defects. Lifetime medical, special education, and rehabilitation costs were assessed. Using a discount rate of 3%, the average direct lifetime cost per surviving CRS patient was estimated at 18,644 US dollars. When including predicted lost productivity due to CRS, the average discounted direct and indirect lifetime costs per surviving CRS patient amounted to 98,734 US dollars.

An epidemiological and clinical study of ocular manifestations of congenital rubella syndrome in Omani children.

OBJECTIVE: To conduct a follow-up study in patients with congenital rubella syndrome (CRS) in Oman and analyze the prevalence of ophthalmic disorders and associated systemic problems. METHODS: This historical prospective cohort study included review of 32 surviving patients with CRS reported by the surveillance system in Oman from 1987 through 2002. All patients underwent a complete ophthalmic examination that included visual acuity estimation, refraction and anterior and posterior segment evaluation, and intraocular pressure measurement. Pediatric and otorhinolaryngologic consultations were also performed. RESULTS: The age-adjusted prevalence of CRS in Oman was 73.2 per million in the Omani population younger than 20 years, and the incidence was 0.6 per 1000 live births. Cataract, retinitis, microphthalmos, and glaucoma were observed in 11, 16, 6, and 4 patients, respectively. Keratoconus, corneal hydrops, and spontaneous resorption of lens were found in 1 patient each. Vision testing was possible in 16 children; 4 were bilaterally blind. Patients who had undergone eye surgery had significantly lower visual acuity, as compared with those who had not undergone surgery (relative risk 2.53; 95% confidence interval, 1.07-6.13). Among the 11 patients with CRS with cataract, we found hearing loss, cardiac anomalies, and neuropsychologic anomalies in 7, 4, and 6 children, respectively. CONCLUSIONS: Congenital rubella syndrome has a wide variety of severe ophthalmic and systemic complications. High clinical vigilance for signs of CRS and regular observation of surviving patients with CRS is desirable. In patients with cataract, the functional results of surgery, despite state-of-the-art ophthalmic care, continue to be poor. Because of a high prevalence of visual, audiologic, and neurologic disabilities, surviving patients with CRS pose a burden on the medical and social communities. Emphasis in management ought to be prevention of CRS through effective immunization programs.