Identification and characterisation of mosquitoes from different locations in Qatar in 2017-2019.

Mosquito-borne infections have considerable consequences for public health. The mere presence of a single case of vector-borne disease (VBD) introduces a risk to the local community particularly when associated with the compatible vector, host, and suitable environmental factors. Presently, there is no well-established vector control and surveillance programme in Qatar; therefore, the likelihood of VBDs spreading is undetermined. As a result, there is a pressing need to address this gap and enable successful management of VBDs. This study presents the results of three consecutive field surveys conducted between 2017 and 2019 with the aim of defining the types and distribution of mosquitoes that are of public health importance in Qatar. The results of the adult mosquito trappings show that the southern house mosquito Culex quinquefasciatus is the most widespread and abundant mosquito species, followed by Cx. perexiguus, both species representing a risk of West Nile virus transmission. All sampling methods show that the malaria vector Anopheles stephensi is widespread including in urbanised areas, suggesting a risk of local malaria transmission. The wetland mosquito Aedes caspius is also widespread, representing a risk of Rift Valley fever virus transmission. The dengue vector Ae. aegypti was not detected and can be considered neither widespread nor abundant, suggesting a minimal risk for local transmission of dengue, chikungunya and Zika viruses. Interestingly, the study detected Culiseta longiareolata for the first time in Qatar. Regular field studies are needed to further address the knowledge gaps in terms of distribution, ecology, and biting habits of different mosquito species currently present in Qatar to accurately assess the risk of mosquito-borne diseases.

TITLE: Identification et caractérisation des moustiques de différents sites du Qatar en 2017­2019. ABSTRACT: Les maladies transmises par les moustiques posent de considérables risques en santé publique. La simple présence d'un cas de maladie à transmission vectorielle (MTV) introduit un risque pour la communauté locale lorsque associé à un vecteur, un hôte et des facteurs environnementaux compatibles. À ce jour il n'y a pas de programme de surveillance et de contrôle des vecteurs bien établi au Qatar, et de ce fait la probabilité de diffusion de MTV est indéterminée. C'est pourquoi il existe un besoin pressant de combler ce vide et de permettre une gestion effective des MTV. Ce travail présente les résultats de trois études de terrain successives conduites entre 2017 et 2019, dans l'objectif de caractériser les moustiques d'importance en santé publique et leur distribution au Qatar. Les résultats des piégeages d'adultes révèlent que le moustique domestique méridional Culex quinquefasciatus est l'espèce la plus répandue et abondante, suivie de Cx. perexiguus, les deux espèces présentant un risque pour la transmission du virus West Nile. L'ensemble des échantillonnages montrent que le vecteur du paludisme Anopheles stephensi est largement répandu y compris dans les zones urbanisées, ce qui suggère un risque de transmission locale du paludisme. Le moustique des zones humides Aedes caspius est également largement répandu, présentant un risque pour la transmission du virus de la fièvre de la Vallée du Rift. Le vecteur de la dengue Ae. aegypti n'a pas été détecté et peut être considéré ni répandu ni abondant, ce qui suggère un risque minimal de transmission locale des virus dengue, chikungunya et Zika. Il est intéressant de noter que cette étude a détecté la présence de Culiseta longiareolata pour la première fois au Qatar. Des études de terrain régulières sont nécessaires pour mieux combler les lacunes de connaissances en termes de distribution, écologie et comportement trophique des différentes espèces de moustiques présentes au Qatar, et d'évaluer plus précisément le risque de maladies transmises par les moustiques.

A retrospective epidemiological study on the incidence of salmonellosis in the State of Qatar during 2004-2012.

BACKGROUND: Salmonella is a food- and water-borne pathogen that can be easily spread in a population, leading to the outbreak of salmonellosis that is caused by ingestion of mixed salads contaminated by the pathogen. Most cases occur in the late spring months and can be seen as single cases, clusters, or episodes. OBJECTIVE: The aim of this study was to describe the incidence and epidemiological characteristics of salmonellosis in the State of Qatar. METHODS: This was a retrospective, descriptive study carried out in laboratory-confirmed cases of salmonellosis during 2004-2012 from all Salmonella surveillance centers. Therapeutic records of patients who were clinically suspected of having Salmonella diseases were analyzed. Initially, cases with typhoid fever were investigated in the laboratory by means of Widal agglutination tests, while non-typhoidal Salmonella diseases were determined based on culture technique. RESULTS: The annual incident of salmonellosis cases were 12.3, 23.0, 30.3, 19.4, 15.3, 18.0, 22.7, 18.5, and 18.1 per 100,000 population in 2006-2011 and 2012, respectively. The number of salmonellosis cases was high among less than 2-year-old females and 3-year-old males. In addition, one-fourth of patients (27.7%) were Qatari when compared to other nationalities. A significant difference in age was found between Qatari (6.08 ± 12.28 years) and non-Qatari (15.04 ± 19.56 years) patients. Of the reported cases, 79.8% included the onset date of the first symptoms. Contact phone numbers were available for 94% of the cases but addresses were available for only 50.4% of cases. The time difference between onset of symptoms and diagnosis was 5.4 ± 5.7 days. The most frequent serotype reported were type b (41.9%), type d (26.9%), and type c1 (12.2%). CONCLUSION: The present surveillance data showed a high incidence of salmonellosis in Qatar that poses a serious public health problem. Special intervention and health awareness programs are required for early screening, detection, and treatment as well as for strengthening the surveillance system of salmonellosis, with special emphasis on the laboratory study of cases.