Epidemiology of respiratory infections among adults in Qatar (2012-2017).

BACKGROUND: Limited data is available about the etiology of influenza like illnesses (ILIs) in Qatar. OBJECTIVES: This study aimed at providing preliminary estimates of influenza and other respiratory infections circulating among adults in Qatar. METHODS: We retrospectively collected data of about 44,000 patients who visited Hamad General Hospital clinics, sentinel sites, and all primary healthcare centers in Qatar between 2012 and 2017. All samples were tested for influenza viruses, whereas about 38,000 samples were tested for influenza and a panel of respiratory viruses using Fast Track Diagnostics (FTD) RT-PCR kit. RESULTS: Among all ILIs cases, 20,278 (46.5%) tested positive for at least one respiratory pathogen. Influenza virus was predominating (22.6%), followed by human rhinoviruses (HRVs) (9.5%), and human coronaviruses (HCoVs) (5%). A detection rate of 2-3% was recorded for mycoplasma pneumonia, adenoviruses, human parainfluenza viruses (HPIVs), respiratory syncytial virus (RSV), and human metapneumovirus (HMPV). ILIs cases were reported throughout the year, however, influenza, RSV, and HMPV exhibited strong seasonal peaks in the winter, while HRVs circulated more during fall and spring. Elderly (>50 years) had the lowest rates of influenza A (13.9%) and B (4.2%), while presenting the highest rates of RSV (3.4%) and HMPV (3.3%). While males had higher rates of HRVs (11.9%), enteroviruses (1.1%) and MERS CoV (0.2%), females had higher proportions of influenza (26.3%), HPIVs (3.2%) and RSV (3.6%) infections. CONCLUSION: This report provides a comprehensive insight about the epidemiology of ILIs among adults in the Qatar, as a representative of Gulf States. These results would help in improvement and optimization of diagnostic procedures, as well as control and prevention of the respiratory infections.

Epidemiology and clinical outcomes of viral central nervous system infections.

BACKGROUND: Central nervous system (CNS) viral infections are an important cause of morbidity and mortality. No data are available regarding their epidemiology in Qatar. DESIGN: We retrospectively evaluated all cerebrospinal fluid findings from January 2011-March 2015 at Hamad Medical Corporation. Those with abnormal CSF finding were included in our study. We excluded those with missing medical records, no clinical evidence of viral CNS infection, or proven bacterial, fungal or tuberculosis CNS infection. CNS clinical findings were classified as meningitis, encephalitis or myelitis. RESULTS: Among 7690 patients with available CSF results, 550 cases met the inclusion criteria (meningitis 74.7%; encephalitis 25%; myelitis 0.4%). Two-thirds (65%) were male and 50% were between 16-60 years old. Viral etiology was confirmed in 38% (enterovirus, 44.3%; Epstein-Barr virus, 31%; varicella zoster virus, 12.4%). The estimated incidence was 6.4 per 100,000 population. Two persons died and the rest were discharged to home. Among those with confirmed viral etiology, 83.8% received ceftriaxone (mean duration 7.3±5.2 days), 38% received vancomycin (mean duration 2.7±5.4 days) and 38% received at least one other antibiotic. Intravenous acyclovir was continued for more than 48h in patients with confirmed negative viral etiology (mean duration 5±5.6 days). CONCLUSION: Viral etiology is not uncommon among those evaluated for CNS infection in Qatar. Clinical outcomes are excellent in this group of patients. Antibiotics and acyclovir are overly used even when a viral etiology is confirmed. There is a need for clinician education regarding etiology and treatment of viral CNS infections.

Characterising the aetiology of severe acute gastroenteritis among patients visiting a hospital in Qatar using real-time polymerase chain reaction.

BACKGROUND: Acute gastroenteritis (AGE) remains a common cause of clinic visits and hospitalizations, though its aetiology has not been determined in Qatar. METHODS: We performed a prospective, emergency department-based study of 288 children and adults with AGE. Stool specimens were collected at presentation from June to November 2009. Faecal specimens were tested, using real-time PCR, for a panel of four viral (norovirus, adenovirus, astrovirus and rotavirus) and bacterial pathogens. RESULTS: Viral and bacterial pathogens were detected in 131 (45.5%) and 34 (12.2%) of the 288 patients recruited. The most commonly detected pathogens were norovirus (28.5%), rotavirus (10.4%), followed by adenovirus (6.25%) and astrovirus (0.30%). Norovirus was the most commonly detected viral pathogen amongst all the age groups with an almost even distribution in all age groups. Rotavirus and adenovirus were more common in children under 5 yr of age. Astrovirus was found in only one person. CONCLUSIONS: Viruses, especially noroviruses, are associated with severe diarrhoea in children and adults in Qatar. Further studies to confirm the findings and to explore the causes of illness among patients from whom a pathogen cannot be determined are needed.

Evidence of occult hepatitis B virus infection among Omani blood donors: a preliminary study.

OBJECTIVES: The aim of this study was to determine the prevalence of hepatitis B surface antigen (HBsAg), hepatitis B core antibodies (anti-HBc) and hepatitis B virus (HBV) DNA among a selected group of Omani blood donors. MATERIALS AND METHODS: Two hundred HBsAg-negative donors were screened for anti-HBc. Those found to be positive were investigated for HBV DNA by polymerase chain reaction. HBsAg was retested on these sera following an immune complex dissociation technique. RESULTS: HBsAg was present in 2.8% of the donors. Forty-one out of 200 (20.5%) HBsAg-negative donors were positive for anti-HBc. Eleven were positive for HBsAg after dissociation, whereas 8 gave readings just over the cutoff. HBV DNA was not detected in this group. CONCLUSION: Findings indicate that testing donors for HBsAg alone is not sufficient to eliminate HBV from the blood supply in Oman.

Detection of serum antibodies to hepatitis C virus in 'false-seronegative' blood donors in Oman.

OBJECTIVE: To detect hepatitis C virus (HCV) antibodies in seronegative donors by disruption of the immune complexes (ICs). SUBJECTS AND METHODS: HCV antibody detection was carried out on 600 seronegative donors following an IC dissociation assay. Reverse transcription polymerase chain reaction (RT-PCR) was then performed on the positive results. RESULTS: Nine of the 600 samples (1.5%) were positive for IC-dissociated HCV antibodies. Of the 9 only 3 antibody-positive samples had detectable HCV RNA. CONCLUSION: Screening for antibodies to HCV in combination with PCR appears to be the safest way to reduce the residual risk of HCV in blood transfusion.

Human immunodeficiency virus type 1 infection in Oman: antiretroviral therapy and frequencies of drug resistance mutations.

Highly active antiretroviral therapy (HAART), consisting mainly of two nucleoside reverse transcriptase inhibitors (NRTIs) and one protease inhibitor (PI), is offered to < 10% of HIV-infected subjects in Oman. The aims of the present study were to determine the frequency of resistance-associated mutations in these patients, and to assess the contribution of drug resistance to treatment outcome. Among 29 patients on HAART for > or =6 months, virological, failure was observed in 27 (93%). Genotypic analysis indicated that in five of these 27 patients, there were no mutations that confer resistance to reverse transcriptase inhibitors (RTIs). The genotypes of 17 other patients carried one or two RTI mutations, mainly the lamivudine-associated resistance mutation M184V. Three or more RTI mutations were found in only five (14.7%) patients with virological failure, including three patients on the nonnucleoside RTI efavirenz. Major PI mutations were infrequent, and were detected in seven (26%) of 27 patients failing HAART, mainly as single mutation at codons 82 or 90. In contrast, accessory mutations in the protease gene were present in all patients. However, there were significant differences in the prevalence of accessory mutations at codons 36 and 77 among clade B and non-B viruses. When genotypic data of this study were used to change therapy of seven patients whose isolates had multiple resistance mutations, adequate viral suppression was observed in five. Our results indicate that the high rate of treatment failure among patients in Oman is mainly due to factors other than resistance to antiretroviral drugs. These factors, which may include nonadherence to therapy and treatment interruptions, need to be investigated.

Awareness of hepatitis B virus among undergraduate medical and non-medical students.

OBJECTIVE: To investigate the awareness of Omani medical and non-medical students of hepatitis-B virus (HBV) infection. METHODS: A structured questionnaire of 31 different statements concerning basic knowledge of HBV, its modes of transmission, diagnosis, risk behaviors, prevention, treatment, beliefs as well as attitudes towards patients with HBV infection were distributed to 280 students (154 females and 126 males). Of these 138 were pre-clinical medical students and 142 were non-medical students. The study was conducted at Sultan Qaboos University, Muscat, Sultanate of Oman during the period of 2001 to 2003. RESULTS: The majority of the students (75%) were aware that HBV is a common cause of hepatitis and 50.7% of them think that HBV infection is preventable. Availability of vaccine is a fact appreciated more by medical (65.2%) than by non-medical (35.2%) students (p<0.05). Approximately 70% of the cohort believed that screening blood for HBV renders blood safe for transfusion. Hepatitis B virus infected student or colleague in the same classroom or working place was accepted by 58% of medical and 46.5% of non-medical students. However, the majority of students (63.2%) hesitate to take care of a HBV infected patient. CONCLUSION: The majority of students showed some knowledge regarding HBV transmission, risk behaviors and prevention. However, there are still misconceptions regarding the attitudes, which reflect a false perception of the disease among students. This calls for well-structured health education programs stressing on such misconceptions.

Laboratory diagnosis of viral hepatitis C: The Sultan Qaboos University Hospital experience.

OBJECTIVES: A retrospective study was carried out to assess the performance of hepatitis C diagnostic assays in our laboratory, and to determine the prevalence of hepatitis C among blood donors at the Sultan Qaboos University Hospital. METHODS: From 1991 to 2001, approximately 55,000 serum samples collected from blood donors and patients were submitted to our laboratory for testing. All sera were screened for antibodies to hepatitis C virus (HCV) by three successive generations of the enzyme-linked immunosorbent assay (ELISA). Anti-HCV positive sera were further tested by recombinant immunoblot assay (RIBA). Reverse-transcriptase polymerase chain reaction (RT-PCR) for HCV RNA was carried out on a limited number (241) of ELISA positive samples. RESULTS: Out of 30012 samples from blood donors that were screened for anti-HCV, 272 (0.91%) were positive. Of these, 46.5% were confirmed positive by RIBA. The proportion of patient sera that were confirmed positive varied from 95% among intravenous drug users to 81% in patients with hepatitis to 70% in those with haemoglobinopathies. HCV RNA was detected in 67%, 6%, and 0% of the RIBA positive, indeterminate and negative samples respectively. CONCLUSIONS: Based on RIBA, the prevalence of anti-HCV among blood donors in Oman is close to 0.5%. In our experience, RIBA-positivity is predictive of HCV infection in two thirds of subjects, and HCV infection is highly unlikely in those who are RIBA-negative. The experience at SQUH with three types of HCV assays has enabled the laboratory to develop a test algorithm, starting with screening anti-HCV ELISA.

Fluctuating antibody response in a cohort of hepatitis C patients.

OBJECTIVE: This project was designed to longitudinally study persons who had antibodies to hepatitis C virus (HCV) to characterise the serologic course of infection. METHODS: The subjects were 149 multitransfused patients (141 with thalassaemia major, 3 with thalassaemia intermedia, and 5 with sickle cell anaemia) who had been regularly followed up for 3 to 7 years. Sequential serum samples obtained semi-annually between January 1994 and January 2001 were tested, prospectively, by second or third generation HCV enzyme-linked immunosorbent assay (ELISA), followed by confirmatory recombinant immunoblot assay (RIBA-2 or RIBA-3). RESULTS: Of the 149 patients, 90 did not seroconvert to HCV, whereas 59 had detectable antibodies. On the basis of RIBA results in these 59 patients, 24 (41%) had persistent high antibody levels to structural and non structural HCV antigens, 11 (19%) had persistent low antibody levels, 17 (29%) showed fluctuating antibody levels, and in 5 patients (8%) there was a total or a partial disappearance of specific antibodies (seroreversion), mainly anti-core antibodies. Two patients (3%) had antibody responses that did not fit into any of these four categories. In patients with fluctuating antibody levels, there were periods ranging from 6 months to 2 years when anti-HCV antibodies could not be detected. CONCLUSION: This study shows that the antibody response to HCV in patients who receive frequent blood transfusions is very variable. Individuals who exhibit intermittent seropositivity are a challenge to diagnosis.