Circulation patterns and molecular epidemiology of human respiratory syncytial virus over five consecutive seasons in Morocco.

Background: Respiratory syncytial virus (HRSV) is the leading cause of respiratory tract infections in infants and young children. we investigated the prevalence and characteristics of HRSV in Morocco and explored trends in circulating genotypes through partial G gene analysis of HRSV strains prevalent from 2012 to 2017. Methods: Respiratory samples were gathered from both outpatients and inpatients meeting ILI or SARI case definitions. The patients' ages varied from 1 month to 99 years old. Nucleic acids were extracted and HRSV type/subtype was detected by RT-qPCR. A subset of positive samples was randomly selected in each epidemic year, the complete viral genome was sequenced, phylogenetic analysis was performed using the MEGA7 program and the genotypes were confirmed. Results: The 3679 specimens were collected from 2012 to 2017, of which 726 (19.7%) were positive for HRSV. The 35% (257/726) of HRSV-positives were of the HRSV-A subtype, while the HRSV-B subtype accounted for 61% (442/726). The co-infection rate was 3.7% (27/726). The virus circulates in a periodic pattern, where epidemics occur during the fall months through early spring. HRSV genotype was confirmed in 127 specimens (56 HRSV-A and 71 HRSV-B). Based on phylogenetic analysis, all HRSV-A were ON1 genotype, and HRSV-B were mostly BA9 genotype. HRSV-B belonging to the BA10 genotype was detected in 2012 exclusively. Conclusions: BA9, BA10, and ON1 were the only HRSV genotypes detected between 2012 and 2017. Variations in the G gene amino acid chain were identified in local strains, which suggests an increased need for continuous genomic surveillance.

Factors associated with hospitalization for seasonal influenza in Morocco.

Background: Morocco is actively working towards expanding its influenza vaccine policy to cover high-risk groups, as recommended by the World Health Organization (WHO). Aims: We assessed the risk factors for influenza-associated hospitalization for severe acute respiratory infections (SARI) that occurred during the last 5 seasons. Methods: We conducted a retrospective, analytical study among patients recruited in the ambulatory and hospital sites of the influenza sentinel surveillance system in Morocco between 2014 and 2019. Using multiple logistic regression, we compared the characteristics of influenza-positive patients with SARI to those with influenza-like illness (ILI) to identify factors associated with severe disease. Results: We included 1323 positive influenza patients with either SARI (41.7%) or ILI diagnosis (58.3%). A(H1N1)pdm09, A(H3N2) and influenza B, respectively, contributed 49.2%, 29.5% and 20.6% of the cases. The main risk factors considered in the bivariate analysis were found in the multivariate analysis to be significantly associated with influenza-related hospitalization (SARI): age < 2 years (aOR = 7.08, P < 0.001); age ≥ 65 years (aOR = 3.59, P < 0.001); diabetes (aOR = 1.98, P = 0.017); obesity (aOR = 2.94, P = 0.034); asthma or chronic respiratory disease (aOR = 4.99, P < 0.001); chronic renal failure (aOR = 4.74, P = 0.005); pregnancy (aOR = 7.49, P < 0.001); and the A(H1N1)pdm09 subtype (aOR = 1.82, P < 0.001). Conclusion: This study provides epidemiological evidence for the expected benefit of an influenza vaccination strategy for high-risk groups as recommended by the WHO.

Viral aetiology of influenza-like illnesses and severe acute respiratory illnesses in Morocco, September 2014 to December 2016.

Background: There is a scarcity of information on the viral aetiology of influenza-like illness (ILI) and severe acute respiratory infection (SARI) among patients in Morocco. Methods: From September 2014 to December 2016, we prospectively enrolled inpatients and outpatients from all age groups meeting the World Health Organization (WHO) case definition for ILI and SARI from 59 sentinel sites. The specimens were tested using real-time monoplex reverse-transcription polymerase chain reaction method for detecting 16 relevant respiratory viruses. Results: At least one respiratory virus was detected in 1423 (70.8%) of 2009 specimens. Influenza viruses were the most common, detected in 612 (30.4%) of processed samples, followed by respiratory syncytial virus (RSV) in 359 (17.9%), human rhinovirus (HRV) in 263 (13.1%), adenovirus (HAdV) in 124 (6.2%), parainfluenza viruses (HPIV) in 107 (5.3%), coronaviruses (HCoV) in 94 (4.7%), human bocavirus (HBoV) in 92 (4.6%), and human metapneumovirus (HMPV) in 74 (3.7%). From 770 samples from children under 5 years old, RSV (288, 36.6%), influenza viruses (106, 13.8%), HRV (96, 12.5%) and HAdV (91, 11.8%) were most prevalent. Among 955 samples from adults, Influenza viruses (506, 53.0%), and HRV (167, 17.5%) were most often detected. Co-infections were found in 268 (18.8%) of 1423 positive specimens, and most (60.4%) were in children under 5 years of age. While influenza viruses, RSV, and HMPV had a defined period of circulation, the other viruses did not display clear seasonal patterns. Conclusions: We found that RSV was predominant among SARI cases in Morocco, particularly in children under 5 years of age. Our results are in line with reported data from other parts of the world, stating that RSV is the leading cause of lower respiratory tract infections in infants and young children.

Ambient air pollution and emergency department visits among children and adults in Casablanca, Morocco.

This study presents the relationships between ambient air pollutants and morbidity and emergency department visits among children and adults performed in Great Casablanca, the most populated and economic region in Morocco. This research was analyzed using conditional Poisson model for the period 2011-2013. In the period of study, the daily average concentrations of SO2, NO2, O3 and PM10 in Casablanca were 209.4 µg/m3, 61 µg/m3, 113.2 µg/m3 and 75.1 µg/m3, respectively. In children less than 5 years old, risk of asthma could be increased until 12% per 10 µg/m3 increase in NO2, PM10, SO2 and O3. In children over 5 years and adults, an increase of 10 µg/m3 air pollutant can cause an increase until 3% and 4% in respiratory consultations and acute respiratory infection, respectively. Similarly, impact on emergency department visits due to respiratory and cardiac illness was established. Our results suggest a not negligible impact on morbidity of outdoor air pollution by NO2, SO2, O3, and PM10.

Influenza epidemiology and risk factors for severe acute respiratory infection in Morocco during the 2016/2017 and 2017/2018 seasons.

INTRODUCTION: in order to implement an influenza vaccination program for high-risk-groups in Morocco, as recommended by the World Health Organization, an epidemiological study indicating the influenza virus effect in the development of complicated influenza for subjects with co-morbidity was required. The present study aims to evaluate the risk factors for severe acute respiratory infections caused by influenza in risk groups. METHODS: this research is based on the epidemiological and virological surveillance data of severe acute respiratory infections and influenza-like illness during the 2016/2017 and 2017/2018 seasons. It was realized using a retrospective series study with a descriptive and analytical purpose. RESULTS: the over-recruitment of pediatric cases with a severe acute respiratory infection has been significantly rectified because cases of severe acute respiratory infections under 15 years old in the 2017/2018 season represent only 57.9%, whereas they represented 75.9% of the total cases of severe acute respiratory infections during the 2016/2017 season. The influenza positivity rate has increased globally and specifically by age group, clinical service and co-morbidity. The risk factors considered were significantly associated with hospitalization for influenza-associated severe acute respiratory infections. The multivariate logistic regression analysis considers male sex (OR=2.1), age ≥65 years (OR=5.4), presence of influenza cases in the surroundings (OR=0.1), diabetes (OR=7.5) and chronic respiratory disease (OR=10.9) as risk factors influenza-associated severe acute respiratory infections. CONCLUSION: the risk assessment of influenza-associated severe acute respiratory infections in high-risk groups revealed national epidemiological findings, particularly for diabetics and the elderly. An influenza vaccination program for these high-risk-groups becomes much recommended in Morocco.

Establishing seasonal and alert influenza thresholds in Morocco.

BACKGROUND: Several statistical methods of variable complexity have been developed to establish thresholds for influenza activity that may be used to inform public health guidance. We compared the results of two methods and explored how they worked to characterize the 2018 influenza season performance-2018 season. METHODS: Historical data from the 2005/2006 to 2016/2018 influenza season performance seasons were provided by a network of 412 primary health centers in charge of influenza like illness (ILI) sentinel surveillance. We used the WHO averages and the moving epidemic method (MEM) to evaluate the proportion of ILI visits among all outpatient consultations (ILI%) as a proxy for influenza activity. We also used the MEM method to evaluate three seasons of composite data (ILI% multiplied by percent of ILI with laboratory-confirmed influenza) as recommended by WHO. RESULTS: The WHO method estimated the seasonal ILI% threshold at 0.9%. The annual epidemic period began on average at week 46 and lasted an average of 18 weeks. The MEM model estimated the epidemic threshold (corresponding to the WHO seasonal threshold) at 1.5% of ILI visits among all outpatient consultations. The annual epidemic period began on week 49 and lasted on average 14 weeks. Intensity thresholds were similar using both methods. When using the composite measure, the MEM method showed a clearer estimate of the beginning of the influenza epidemic, which was coincident with a sharp increase in confirmed ILI cases. CONCLUSIONS: We found that the threshold methodology presented in the WHO manual is simple to implement and easy to adopt for use by the Moroccan influenza surveillance system. The MEM method is more statistically sophisticated and may allow a better detection of the start of seasonal epidemics. Incorporation of virologic data into the composite parameter as recommended by WHO has the potential to increase the accuracy of seasonal threshold estimation.

Effect of monovalent rotavirus vaccine on rotavirus disease burden and circulating rotavirus strains among children in Morocco.

Rotarix(TM) vaccine was introduced into the National Program of Immunization of Morocco in October 2010, reaching quickly 87% of the target population of children nationally. The incidence of rotavirus gastroenteritis and the prevalence of circulating rotavirus strains has been monitored in three sentinel hospitals since June 2006. The average percentage of rotavirus positive cases among all children under 5 years old hospitalized for gastroenteritis during the pre-vaccine period (2006-2010) was 44%. This percentage dropped to 29%, 15% and 24% in the 3 years post vaccine introduction (2011, 2012 and 2013), which is a decline of 34%, 66%, and 45%, respectively. Declines in prevalence were greatest among children 0-1 years of age (53%) and were most prominent during the winter and autumn rotavirus season. The prevalence of the G2P[4] and G9P[8] genotype sharply increased in the post vaccine period (2011-2013) compared to the previous seasons (2006-2010). Rotavirus vaccines have reduced greatly the number of children hospitalized due to rotavirus infection at the three sentinel hospitals; it is however unclear if the predominance of G2P[4] and G9P[8] genotypes is related to the vaccine introduction, or if this is attributable to normal genotype fluctuations. Continued surveillance will be pivotal to answer this question in the future.

Smoking-attributable mortality in Morocco: results of a prevalence-based study in Casablanca.

BACKGROUND: Tobacco control measurements' had little impact on smoking prevalence in Morocco. The aim of this study is to provide first data on smoking attributable mortality in Morocco. METHOD: The Smoking-Attributable Mortality, Morbidity and Economic Costs (SAMMEC) software was used to estimate the smoking attributable mortality (SAM) in Casablanca region in 2012. Smoking prevalence and mortality data of people aged 35 years or older were obtained from the national survey on tobacco "Marta" and from Health Ministry Mortality System, respectively. RESULTS: Of the 5261deaths of persons aged 35 years and older, 508 (9.7%) were attributable to cigarette smoking. This total represents 16.2% of all male deaths (n =448) and 2.0% (n =80) of all female deaths in this region. The leading four causes of smoking attributable deaths were lung cancer (177), chronic airways obstruction (76), ischemic heart disease (39), and cerebrovascular disease (31). CONCLUSION: Tobacco use caused one out of six deaths in Casablanca in 2012. Four leading causes (lung cancer, ischemic heart disease, cerebrovascular disease and chronic airways obstruction,) accounted for 51.6% of SAM. Effective and comprehensive actions must be taken in order to slow this epidemic in Morocco.

Needs assessment for performance improvement of personnel in charge of epidemiological surveillance in Morocco.

BACKGROUND: In line with the International Health Regulations (IHR 2005), the Morocco health surveillance system has been reinforced via infrastructure strengthening and decentralization in its regions. To plan for personnel capacity reinforcement actions, a national workforce needs assessment was conducted by the National Epidemiological Surveillance Service and the World Health Organization. METHODS: The assessment used an ad-hoc method comprising two stages: (1) A survey via a standardized electronic questionnaire, administered to all staff in regional and provincial surveillance teams. Data collected included demographics, basic qualification, complementary training, perceived training needs, and preferred training modalities. Individuals were asked to grade, on a nine-point scale, their perception of importance of a given list of tasks and of their capacity to perform them. The gap between perceptions was quantified and described. (2) Field visits to national, regional and provincial sites for direct observation and opinion gathering on broader issues such as motivators, barriers, and training needs from the local perspective. RESULTS: Questionnaire respondents were 122/158 agents at 78 surveillance units countrywide. Mean age was 43.6 years and job longevity 5.7 years. Only 53% (65/122) had epidemiology training, posted in 62% (48/78) of the structures. Self-assessed capacity varied by basic qualification and by structure level (regional vs. provincial). The gap between the importance granted to a task and the perceived capacity to perform it was sizable, showing an uneven distribution across competency domains, regions, surveillance level and staff's basic qualification. From the opinions gathered, a problem of staff demotivation and high turnover emerged clearly. CONCLUSIONS: Our method was successful in revealing specific details of the training needs countrywide. A national strategy is needed to ensure rational planning of training, personnel motivation and long-term sustainability. In terms of training, an innovative program should target the specific needs per group and per region.

Diversity of rotavirus strains circulating in children under 5 years of age admitted to hospital for acute gastroenteritis in Morocco, June 2006 to May 2009.

Rotavirus vaccine was introduced in Morocco during 2010. In anticipation of introducing rotavirus vaccines, the Ministry of Health in Morocco established a rotavirus surveillance network in June 2006 at four hospitals in Morocco to obtain baseline data on rotavirus disease burden and prevalent strains. From June 2006 to May 2009, stool samples were collected from children under 5 years of age admitted for diarrhea to four sentinel hospitals serving different regions of Morocco. Rotaviruses were detected in stools using enzyme immunoassay, then genotyped by reverse-transcriptase polymerase chain reaction. Samples with adequate stool in which the P or G types could not be determined by RT-PCR were subjected to nucleotide sequence analysis. Overall, 42% (579 of 1,388) of the stools samples tested were positive for rotavirus. Genotyping of 548 (95%) samples demonstrated that G1P[8] (55%) was the most prevalent strain, followed by G9P[8] (11.3%), G2P[4] (9.1%), G4P[8] (0.9%), and G3P[8] (0.4%). Several other strains were identified including G1P[4] (0.2%), G1P[6] (0.9%), G2P[6] (4.3%), G2P[8] (0.2%), G3P[6] (0.4%), G3P[4] (0.2%), and G9P[6] (0.2%). A high prevalence of mixed infections was found (15% of all samples) of which G1G2P[8] (4%) and G1G3P[8] (3.6%) accounted for the majority. Considerable diversity of rotavirus genotypes was present among strains circulating in Morocco prior to the introduction of the vaccine. This study highlighted the need for maintaining active surveillance to monitor changes in rotavirus disease burden and strain dynamics and to detect changes over time that could impact the effectiveness of the vaccination program.

Monitoring of rotavirus vaccination in Morocco: establishing the baseline burden of rotavirus disease.

BACKGROUND: Rotavirus is a leading cause of childhood morbidity and mortality worldwide. Clinical trials for two rotavirus vaccines recommended by the WHO for global use since 2009 have successfully demonstrated the safety and efficacy of these vaccines in a wide range of countries. To control the burden of severe and fatal diarrheal disease, the Ministry of Health of Morocco introduced the single strain rotavirus vaccine into their national immunization program in 2010. METHODS: We employed a standard WHO case definition to identify children under 5 hospitalized with AGE at four hospitals from June 2006 to May 2010 to establish baseline burden of rotavirus disease before introduction of vaccine. Stool samples were collected and tested for rotavirus using a standard enzyme immunoassay. RESULTS: Overall, 40% (741 of 1841) of the children hospitalized with AGE tested positive for rotavirus, making it the single most common cause of severe gastroenteritis among children in Morocco. Applying this prevalence to the estimates of diarrheal hospitalizations and deaths in Morocco, we estimate that rotavirus annually causes 19,646 hospitalizations and 1604 deaths in children under 5 years of age. DISCUSSION: On the basis of these surveillance data, we estimate that 1 in 389 Moroccan children died and 1 in 32 was hospitalized due to rotavirus before their fifth birthday. A considerable proportion of these deaths and hospitalizations should be preventable through vaccination, and the 4 years of stable prevaccine surveillance in Morocco will be a tremendously useful platform for assessing potential changes in the epidemiology of rotavirus disease and measuring impact of the new rotavirus vaccine program in Morocco.

Genotyping measles virus by real-time amplification refractory mutation system PCR represents a rapid approach for measles outbreak investigations.

Real-time PCR has been developed to genotype measles virus (MV) isolates. MV strains circulating in epidemics in Gabon in 1984, Cameroon in 2001, Morocco in 2003, and France in 2004 were investigated. We developed a real-time amplification refractory mutation system PCR (RT-AMRS PCR) using SYBR green fluorescent dye. Six pairs of primers for RT-ARMS PCR were designed to specifically amplify genotypes A, B2, B3.1, B3.2, C2, and D7. Genotypes could be differentiated by melting curve analysis. All strains were also confirmed by direct sequencing. Using the result obtained by direct sequencing and phylogenetic analysis as the reference, the accuracy of MV by RT-ARMS PCR and melting curve analysis was 97%. However, the latter method is more rapid and sensitive than the former method. This method could be a useful tool for molecular epidemiological studies of MV, providing an efficient alternative for large-scale studies.

Congenital rubella syndrome burden in Morocco: a rapid retrospective assessment.

BACKGROUND: WHO recommends that countries considering introduction of rubella vaccine into their immunisation programme assess their burden of congenital rubella syndrome, to determine whether vaccination is warranted. However, few guidelines exist for such assessments in developing countries. We retrospectively estimated the burden of congenital rubella syndrome in Morocco, and assessed our methods of rapid case finding. METHODS: We undertook case finding in the two cities with Morocco's main tertiary care referral centres, using medical records from births between Jan 1, 1990, and May 31, 2002, disability records from 1965 to 1997, and retinal examinations from deaf students born between 1985 and 1994, applying the WHO definition for a clinically confirmed case of congenital rubella syndrome. We also reviewed disability data for evidence of epidemic periodicity and estimated yearly incidence of the syndrome from congenital cataract data for births between 1990 and 2001. FINDINGS: We identified 62 clinically confirmed cases of congenital rubella syndrome from medical records, 148 from disability records, and 15 in deaf students. We noted no epidemic periodicity in disability data, and estimated a yearly incidence of the syndrome in Morocco of 8.1-12.7 cases per 100000 livebirths. INTERPRETATION: We show evidence of congenital rubella syndrome in Morocco and support the addition of rubella vaccination to the national programme. Various data sources can be explored to rapidly assess burden of the syndrome; ophthalmology departments and outpatient cardiology clinics could offer the most potential for such case finding, dependent on documentation practices.