Considerations for introduction of a rotavirus vaccine in Oman: rotavirus disease and economic burden.

Rotavirus is the most common cause of fatal childhood diarrhea worldwide. We provide the first estimates of the health care and economic burden of severe rotavirus disease in Oman. We conducted active, hospital-based surveillance of rotavirus disease at 11 regional public hospitals in Oman, using the guidelines suggested by the generic World Health Organization protocol. From July 2006 through June 2008, all children aged <5 years who were hospitalized for acute gastroenteritis were enrolled in the surveillance program, and their stool samples were tested for rotavirus using a commercially available enzyme immunoassay (ID EIA Rotavirus Test; Dako Diagnostics). Rotavirus was detected in samples from 1712 (49%) of 3470 children. These children were hospitalized for a median of 3 days for severe diarrhea. A marked seasonal peak was evident with a majority of the cases occurring from December through May. Of the rotavirus cases, 69% occurred in children aged 6-17 months. We identified a diverse strain pattern in Oman, with G2 (37%), G1 (38%), and G9 (11%) accounting for most of typeable strains. By our burden estimates, the Omani government spends an estimated US$791,817 and US$1.8 million annually to treat rotavirus-associated diarrhea in the outpatient and hospital settings, respectively. A rotavirus vaccination program might substantially reduce the burden of severe diarrhea among children in Oman.

Acute tubular necrosis associated with non-hemorrhagic Dengue fever: a case report.

Dengue fever (DF) is an arthropod-born viral infection affecting humans. Dengue viruses are transmitted through the bites of the mosquito Aedes aegypti. Acute renal failure (ARF) is reported in patients who are affected mainly with Dengue hemorrhagic fever (DHF), which is a severe presentation of the disease. We report the case of a 24-year-old Omani female with no past history of particular medical problems. She was referred to our hospital for the further management of acute renal failure. She had clinical features of DF without DHF. The kidney biopsy showed features of acute tubular necrosis (ATN). She had a complete recovery after 25 days and required three sessions of hemodialysis. We conclude that DF even without DHF may lead to ATN and ARF. Clinicians should be aware of this etiology. Treatment is supportive and may require dialysis. The prognosis could be favorable.

Measles epidemiology and its implications for a vaccination programme in Oman.

To describe the epidemiology of measles in Oman and the implications for a vaccination programme, we conducted a retrospective record-based study from 1 January 2000 to 31 December 2003 using data from the national epidemiological surveillance system. All cases notified as suspected measles during the study period were included. Of the 185 notified cases, 19.4% were confirmed measles positive. Blood samples for measles IgM were collected in 97.3% of cases. The mean age of measles cases was 8.0 (SD 10.7) years. The estimated overall incidence rate of measles for the study period was 0.53 per 100,000 person-years. Regression analysis indicated measles was significantly commoner among non-Omanis and children who had not been vaccinated.

External quality control of Mycobacterium tuberculosis drug susceptibility testing: results of two rounds in endemic countries.

SETTING: Quality assurance for the World Health Organization (WHO)/International Union Against Tuberculosis and Lung Disease (The Union) global tuberculosis (TB) drug resistance surveillance programme. OBJECTIVE: To monitor the quality of drug susceptibility testing (DST) in different countries. METHODS: In 2002-2003 and 2005-2006, 20 Mycobacterium tuberculosis strains were sent by the WHO/Union Supranational Reference Laboratory of Rome to TB reference laboratories in Albania, Bahrain, Kosovo, Mozambique, Oman, Qatar and Turkey for external quality control (EQC). RESULTS: In 2002-2003, the specificity, sensitivity, efficiency, reproducibility and predictive values for resistance/susceptibility were >or=90% for streptomycin (SM), isoniazid (INH) and ethambutol (EMB). In 2005-2006, all statistical values were >or=96% for SM, INH, rifampicin and EMB. CONCLUSION: EQC improved the quality of M. tuberculosis DST in the participating countries.

Measles epidemiology and its implications for a vaccination programme in Oman

To describe the epidemiology of measles in Oman and the implications for a vaccination programme, we conducted a retrospective record-based study from 1 January 2000 to 31 December 2003 using data from the national epidemiological surveillance system. All cases notified as suspected measles during the study period were included. Of the 185 notified cases, 19.4% were confirmed measles positive. Blood samples for measles IgM were collected in 97.3% of cases. The mean age of measles cases was 8.0 [SD 10.7] years. The estimated overall incidence rate of measles for the study period was 0.53 per 100 000 person-years. Regression analysis indicated measles was significantly commoner among non-Omanis and children who had not been vaccinated

Antibiotic-resistant Salmonella spp. from human and non-human sources in Oman.

We investigated the antibiotic resistance of various strains of Salmonella isolated from different sources in Oman, namely sewage water, chicken and food handlers. Of 1242 isolates from food handlers, 15 (1.2%) were resistant to one or more antibiotic. Of these, 41% were resistant to ampicillin, 42% to co-trimoxazole and 22% to chloramphenicol. None of the isolates was resistant to ciprofloxacin. Of 515 isolates from chicken and 432 from sewage water, 23.7% and 14.1% respectively were resistant to one or more antibiotic. Susceptibility to the different antibiotics varied but none of the isolates from chicken was resistant to amikacin.

Antibiotic-resistant Salmonella spp. from human and non-human sources in Oman

We investigated the antibiotic resistance of various strains of Salmonella isolated from different sources in Oman, namely sewage water, chicken and food handlers. Of 1242 isolates from food handlers, 15 [1.2%] were resistant to one or more antibiotic. Of these, 41% were resistant to ampicillin, 42% to co-trimoxazole and 22% to chloramphenicol. None of the isolates was resistant to ciprofloxacin. Of 515 isolates from chicken and 432 from sewage water, 23.7% and 14.1% respectively were resistant to one or more antibiotic. Susceptibility to the different antibiotics varied but none of the isolates from chicken was resistant to amikacin

International collaborative assessment study of the AHD575 method for the measurement of blood haemoglobin.

Accurate, economical methods for haemoglobin determination by laboratories in countries with limited resources are not available. This report provides the results of an international collaborative study evaluating the alkaline haematin detergent (AHD575) method as a reference method for laboratory services with limited resources. The study included 6 laboratories; 3 in East Mediterranean countries, 1 in East Africa and 3 in Europe. The (AHD575) method was evaluated against the HiCN method, with blood samples drawn from healthy and sick subjects. The results indicate that the AHD575 method is suitable for measuring haemoglobin in laboratories at all levels.

International collaborative assessment study of the AHD [575] method for the measurement of blood haemoglobin

Accurate, economical methods for haemoglobin determination by laboratories in countries with limited resources are not available. This report provides the results of an international collaborative study evaluating the alkaline haematin detergent [AHD[575]] method as a reference method for laboratory services with limited resources. The study included 6 laboratories; 3 in East Mediterranean countries, 1 in East Africa and 3 in Europe. The [AHD[575]] method was evaluated against the HiCN method, with blood samples drawn from healthy and sick subjects. The results indicate that the AHD[575] method is suitable for measuring haemoglobin in laboratories at all levels

Holmium laser ablation of anterior urethral valves: case report.

PURPOSE: To report a novel method for treating anterior urethral valves in children using the holmium:YAG laser. CASE REPORT: A 2-year-old boy presented with symptoms of urinary-outflow obstruction. A micturating cystourethrogram (MCUG) revealed an abrupt narrowing of the penile urethra. At cystourethroscopy, an anterior urethral valve without a diverticulum was visible. This was ablated endoscopically using the Ho:YAG laser. The child voided successfully and was discharged the next day. Repeat MCUG 6 months later revealed a normal-caliber urethra. CONCLUSION: Holmium:YAG laser ablation of anterior valves is a minimally invasive treatment modality that provided a satisfactory result and appears to be very promising.

Pharyngeal carriage of serogroup W135 Neisseria meningitidis in Hajjees and their family contacts in Morocco, Oman and Sudan.

In 2000 the global outbreak that began in Saudi Arabia was caused by a W135:2a:P1.5,2 strain of Neisseria meningitidis belonging to the ET-37 complex and to ST-11. There was concern that introduction of this epidemic clone (EC) might lead to a wave of outbreaks in the African meningitis belt. The WHO therefore initiated studies of meningococcal carriage among pilgrims and their family contacts in Morocco, Oman and Sudan, 3 to 12 months after the Hajj 2000. In Morocco, 1186 persons were swabbed 3 times. Ninety-five meningococcal strains were isolated from 2.7% of the specimens. Pulsed-field gel electrophoresis showed that 32 (33.6%) were identical with the EC. In Sudan, 5 strains identical with the EC were obtained after sampling 285 persons. In Oman, among 18 meningococcal strains isolated from 399 subjects, 11 (61.1%) belonged to the EC. The important pharyngeal carriage of W135 (EC) and its role in the 2001-2002 outbreaks in Burkina Faso argues for the necessity of reinforcing surveillance, and adapting and planning responses in Africa and the Middle East using the most appropriate vaccine.

Ureteric calculi in children: preliminary experience with holmium:YAG laser lithotripsy.

OBJECTIVE: To determine the efficacy and safety of holmium:YAG laser lithotripsy in children with ureteric calculi. PATIENTS AND METHODS: Between 1999 and 2003, 28 ureteroscopic laser procedures were carried out on 26 children (14 boys and 12 girls, mean age 6.5 years) with ureteric calculi. The mean (range) stone size was 1.21 (0.4-2.2) cm. At ureteroscopy the calculi were in the upper ureter in six (23%), mid-ureter in five (19%) and lower ureter in 15 (58%) patients. A rigid 8 F ureteroscope was used and the Ho:YAG laser energy delivered at 0.6-1.4 J and 6-10 Hz. All patients were evaluated after 3 months with intravenous urography to confirm stone clearance and to exclude ureteric stricture formation. RESULTS: The overall stone-free rate was 92% (24 children) after 28 ureteroscopic procedures. Stones were completely cleared in 83%, 80% and 100% of the procedures in the upper, mid- and lower ureters, respectively. In two children the procedure failed; they were salvaged by ureterolithotomy in one and extracorporeal shockwave lithotripsy in the other. During the procedures, a ureteric perforation was caused by several factors, including a technically difficult procedure and higher laser energy. At the mean (range) follow-up of 18 (3-39) months, low grade vesico-ureteric reflux was detected in two children, and there were no ureteric strictures in any. CONCLUSION: Holmium:YAG laser lithotripsy is an efficient and safe treatment for ureteric calculi in children.

Pediatric staghorn calculi: the role of extracorporeal shock wave lithotripsy monotherapy with special reference to ureteral stenting.

PURPOSE: Treatment for staghorn calculi in children represents a unique challenge. We assessed the efficacy of extracorporeal shock wave lithotripsy (ESWL) (Dornier Medical Systems, Inc., Marietta, Georgia) monotherapy for the management of staghorn calculi in children with special reference to ureteral stenting. MATERIALS AND METHODS: From June 1992 to January 2001 we treated 42 children 9 months to 12 years old with staghorn stones using the Piezolith 2501 (Richard Wolf GmBH, Knittlingen, Germany) lithotriptor. The initial group of 19 patients underwent ESWL without prophylactic ureteral stenting, while in the latter group of 23 a Double-J (Medical Engineering Corp., New York, New York) ureteral stent was inserted immediately before the first ESWL session. Mean patient age, stone size, number of shock waves and ESWL sessions, hospital stay, stone-free rate and major complications were compared in the 2 groups. RESULTS: Overall 33 children (79%) were stone-free after 3 months. The 2 groups were comparable in regard to patient age, stone size, number of shock waves and ESWL sessions, and stone-free rates. Major complications developed in 21% of the unstented group, whereas none were observed in stented cases. This difference was statistically significant (p = 0.035). Seven post-ESWL auxiliary procedures were required in the unstented group to manage complications. Hospital stay was significantly longer in the unstented compared with the stented group (p = 0.022). At a followup of 9 to 102 months (mean 47) stones recurred in 2 children, who were treated with further ESWL. CONCLUSIONS: ESWL monotherapy was an efficient and safe modality for the treatment of staghorn calculi in children. Stented patients had fewer major complications and a shorter hospital stay. Prophylactic ureteral stenting is advisable before ESWL for staghorn calculi in children.

Poliomyelitis in Oman. I. The last outbreak?

Since 1988, the Sultanate of Oman has experienced three outbreaks of paralytic poliomyelitis. The last outbreak occurred in December 1993 and involved two children aged 10 months and 4 1/2 years. The children had received five and four doses, respectively, of trivalent oral polio vaccine (OPV) and lived in the same village. Serum neutralizing antibody tests suggested that paralytic polio in these children was due to poor antibody response to OPV. Wild poliovirus type 1 was isolated from both patients, as well as from seven of ten close contacts of the older child, and one of eight contacts of the younger child. All contacts had received three to six doses of OPV. Genomic sequence studies indicated that the virus isolates belonged to a genotypic group prevalent in southern and western Asia, but differed markedly from virus isolated during the 1988/89 outbreak, suggesting another importation of poliovirus. In response to the outbreak, supplementary immunization with OPV was given to children <6 years of age, initially in the affected district, and subsequently to children in the whole country. This study demonstrates that immunization with three to six doses of OPV did not prevent infection with wild poliovirus. In those children with sub-optimal response to OPV, infection resulted in paralytic poliomyelitis. The outbreak remained localized in one village, indicating that the outbreak control measures were effective.

Poliomyelitis in Oman. II. Toward eradication.

In the past decade, the Sultanate of Oman has experienced three outbreaks of paralytic poliomyelitis--a widespread polio type 1 epidemic in 1988/1989, four cases of polio type 3 in three different regions in 1991, and a localized type 1 outbreak in 1993. The lessons learnt from each of these epidemics have guided us to modify and improve our polio eradication activities. Currently, these activities include administration of five primary and three booster doses of trivalent oral polio vaccine, yearly national immunization campaigns (NIDs) since 1995 with coverage of >90%, localized immunization campaigns, acute flaccid paralysis (AFP) surveillance which involves reporting of all cases by facsimile to the Department of Surveillance within 24 h of detecting a case and weekly zero reporting from 22 sentinel sites, and virological testing of stool specimens of all AFP cases and their close contacts at the national, World Health Organization accredited laboratory. The cumulative success of these activities has resulted in Oman being free from polio for the past 6 years. However, the possibility of importation of wild poliovirus, particularly from southern and western Asia still exists.

Crimean-congo haemorrhagic fever: a seroepidemiological and tick survey in the Sultanate of Oman.

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.

Paediatric ureteric calculi: efficacy of primary in situ extracorporeal shock wave lithotripsy.

OBJECTIVE: To evaluate the efficacy of primary in situ extracorporeal shockwave lithotripsy (ESWL) for the treatment of ureteric calculi in children. PATIENTS AND METHODS: The Wolf 2500 Piezolith was used to treat 63 children (aged 4 months to 12 years) with 76 ureteric calculi, including 10 children with impacted calculi. The calculi were located in 14 upper, 13 mid and 44 lower ureters, and the stone burden varied from 4 to 17.8 mm (mean 12.6). All children aged < or = 10 years were treated under general anaesthesia; lithotripsy was attempted under intravenous sedation in the older children. RESULTS: At the 3-month follow-up, there was an overall successful outcome in 55 children (87%), which included 12 of 13, eight of nine (89%) and 35 of 41 (85%) of the children with upper, mid and lower ureteric calculi, respectively, and nine of the 10 with impacted calculi. Re-treatment was required in 20 (36%) patients, while auxiliary procedures after ESWL were required in three (6%). The major complications encountered were ureteric obstruction with sepsis in two children, bacteraemia in another and urinary retention due to a urethral stone fragment in a fourth child. CONCLUSIONS: In situ ESWL was an effective treatment modality for ureteric calculi at all levels in children, even when impacted. In the short term, complications were minimal, but the long-term effects need further assessment.

Paediatric ureteroscopy for ureteric calculi: a 4-year experience.

OBJECTIVE: To study the efficacy and safety of ureteroscopy in the management of paediatric ureteric calculi at various levels. PATIENTS AND METHODS: The records of 50 ureteroscopic procedures performed on 43 children (age range 6 months-12 years) for primary ureteric calculi or ureteric fragments after electrohydraulic shockwave lithotripsy (EHWL) were analysed retrospectively. The distribution of the calculi was in nine in the upper upper, seven in the mid and 30 in the lower ureter, with a mean stone burden of 1.26 cm. Ureteroscopy was performed with the 8.5/9.5/11.5 F Wolf ureteroscopes, and EHL was used as the primary method of fragmentation. Intravenous urograms were available in 34 children (79%) and micturating cystography (MCUG) was performed in 23 children (54%) during the follow-up. RESULTS: An overall stone-free status was achieved in 40 children (93%) after performing 47 ureteroscopies (94%). Stones were completely cleared in 78%, 100% and 97% of the procedures in the upper, mid and lower ureters, respectively. In three children the procedure failed and they were salvaged by uretero-lithotomy. During the procedures, an upper ureteric perforation occurred in one patient and a lower perforation in another. MCUG revealed low grade vesico-ureteric reflux in 17% of the patients, but close follow-up showed the reflux to be sterile and clinically insignificant. CONCLUSION: Ureteroscopy was safe and effective for the management of mid and lower ureteric calculi but the results for upper ureteric calculi were marginally inferior. Ureteroscopy must be performed judiciously to minimize ureteric injury in children. The incidence of vesico-ureteric reflux after mechanical dilatation of the intramural ureter was infrequent and clinically insignificant.

HTLV-I seroprevalence in the Sultanate of Oman.

2329 subjects (blood donors and patients) from various areas of the Sultanate of Oman were investigated for the presence of HTLV-I antibody by as enzyme immunoassay (EIA) method. 10 subjects (0.4%), including 9/1586 blood donors (0.6%) and 1/165 patients with sexually transmitted diseases (0.6%), were found to be EIA seropositive with a regional variation in seroprevalence of 0-14%. 6/9 EIA seropositive samples from blood donors yielded 'indeterminate' results on Western immunoblot analysis (WBA). A much larger survey with additional confirmatory assays such as a radioimmunoprecipitation assay (RIPA), should provide a more conclusive picture of the prevalence of this retroviral infection in the Sultanate.