-
Medecine Tropicale Et Sante... Mar 2024The Republic of Djibouti is located in the Horn of Africa, on the Gulf of Aden and the Bab-el-Mandeb detroit, at the southern entrance to the Red Sea. Prior to its... (Review)
Review
BACKGROUND AND JUSTIFICATION
The Republic of Djibouti is located in the Horn of Africa, on the Gulf of Aden and the Bab-el-Mandeb detroit, at the southern entrance to the Red Sea. Prior to its independence in 1977, the Republic of Djibouti was known by two names: "Côte française des Somalis" until 1967, then "Territoire Français de Afars et Issas". As part of our doctoral research on the ecology of mosquitoes in Djibouti, we noted a lack of information on the species encountered, and felt it essential to draw up a list of species before embarking on ecological monitoring. The aim of this work is to survey publications on mosquitoes in Djibouti and to synthesize data from this scientific literature in order to update the national inventory of Culicidae.
MATERIALS AND METHODS
An exhaustive search of electronic bibliographic databases (PubMed, Scopus, HAL Open Archive, Science Direct and Google Scholar) was carried out. Reference lists were filtered to access additional articles in order to obtain more data. Two keywords were used: "Djibouti" and "French Territory of Afars and Issas". A selection of scientific publications on Djibouti mosquitoes and/or diseases transmitted by mosquito vectors was made. Researches were conducted in articles selected. The names of the species listed were checked and validated by referring to the site Mosquito Taxonomic Inventory.
RESULTS
A total of 13 studies, published between 1970 and 2023, were found. Over the years, the composition of the Culicidae fauna has become well known. In part, the movement of people traveling to and from neighboring countries has been linked to the detection of new species and the reappearance of mosquito species in Djibouti. Numerous studies have been carried out over the years, including purely taxonomic studies and others focusing on the incrimination of mosquito vectors and the characterization of the pathogens they transmit. A total of 37 species, belonging to two subfamilies (Anophelinae and Culicinae), of mosquitoes divided between 7 genera and have been mentioned across the country. The number of species per genus is distributed as follows: 5 species of including 1 subspecies, 14 species of including two subspecies, 12 species of including 1 subspecies, 1 species for each of the genera and and finally 2 species respectively for the genera and Five species have been incriminated as vectors of diseases such as malaria, dengue fever, yellow fever, West Nile virus and chikungunya. Others are known for their potential role in pathogen transmission, including Zika and Rift Valley virus.
DISCUSSION - CONCLUSION
The bibliographical research enabled us to summarize the research carried out over more than half a century in the history of Djibouti, and to update the inventory of the country's mosquitoes, which now includes 37 species. Species names were reviewed and updated, and the case of was also addressed. Two species mentioned as part of the Culicidae fauna of Djibouti appeared to be doubtful and are up for discussion. These results provide a useful information base for defining vector control priorities in Djibouti. They will also inform, guide and facilitate future consultations of our database. In addition, this study will help to identify research ways on mosquitoes in Djibouti.
Topics: Animals; Culicidae; Djibouti; Mosquito Vectors
PubMed: 38846112
DOI: 10.48327/mtsi.v4i1.2024.365 -
APMIS : Acta Pathologica,... Jun 2024Acute encephalitis syndrome (AES) is a major public health concern in India as the aetiology remains unknown in the majority of cases with the current testing algorithm....
Acute encephalitis syndrome (AES) is a major public health concern in India as the aetiology remains unknown in the majority of cases with the current testing algorithm. We aimed to study the incidence of Japanese encephalitis (JE) and determine the aetiology of non-JE AES cases to develop an evidence-based testing algorithm. Cerebrospinal fluid (CSF) samples were tested for Japanese encephalitis virus by ELISA and polymerase chain reaction (PCR). Multiplex real-time PCR was done for Dengue, Chikungunya, West Nile, Zika, Enterovirus, Epstein Barr Virus, Herpes Simplex Virus, Adenovirus, Cytomegalovirus, Herpesvirus 6, Parechovirus, Parvovirus B19, Varicella Zoster Virus, Scrub typhus, Rickettsia species, Leptospira, Salmonella species, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Plasmodium species and by ELISA for Mumps and Measles virus. Of the 3173 CSF samples, 461 (14.5%) were positive for JE. Of the 334 non-JE AES cases, 66.2% viz. Scrub typhus (25.7%), Mumps (19.5%), Measles (4.2%), Parvovirus B19 (3.9%) Plasmodium (2.7%), HSV 1 and 2 (2.4%), EBV and Streptococcus pneumoniae (2.1% each), Salmonella and HHV 6 (1.2% each) were predominant. Hence, an improved surveillance system and our suggested expanded testing algorithm can improve the diagnosis of potentially treatable infectious agents of AES in India.
PubMed: 38837462
DOI: 10.1111/apm.13443 -
The key role of Spain in the traffic of West Nile virus lineage 1 strains between Europe and Africa.Infectious Diseases (London, England) Jun 2024West Nile Virus (WNV) is a zoonotic arbovirus worldwide spread. Seasonal WNV outbreaks occur in the Mediterranean basin since the late 1990's with ever-increasing...
BACKGROUND
West Nile Virus (WNV) is a zoonotic arbovirus worldwide spread. Seasonal WNV outbreaks occur in the Mediterranean basin since the late 1990's with ever-increasing incidence. In Southern Spain WNV is endemic, as disease foci - caused by WNV lineage 1 (WNV-L1) strains - occur every year. On the contrary, WNV-L2 is the dominant lineage in Europe, so most European WNV sequences available belong to this lineage, WNV-L1 sequences being still scarce.
METHODS
To fill this gap, this study reports the genetic characterisation of 27 newly described WNV-L1 strains, involved in outbreaks affecting wild birds and horses during the last decade in South-Western Spain.
RESULTS
All strains except one belong to the Western Mediterranean-1 sub-cluster (WMed-1), related phylogenetically to Italian, French, Portuguese, Moroccan and, remarkably, Senegalese strains. This sub-cluster persisted, spread and evolved into three distinguishable WMed-1 phylogenetic groups that co-circulated, notably, in the same province (Cádiz). They displayed different behaviours: from long-term persistence and rapid spread to neighbouring regions within Spain, to long-distance spread to different countries, including transcontinental spread to Africa. Among the different introductions of WNV in Spain revealed in this study, some of them succeeded to get established, some extinguished from the territory shortly afterwards. Furthermore, Spain's southernmost province, Cádiz, constitutes a hotspot for virus incursion.
CONCLUSION
Southern Spain seems a likely scenario for emergence of exotic pathogens of African origin. Therefore, circulation of diverse WNV-L1 variants in Spain prompts for an extensive surveillance under a One Health approach.
PubMed: 38836293
DOI: 10.1080/23744235.2024.2348633 -
International Journal of Biological... Jun 2024Approximately 3.9 billion individuals are vulnerable to dengue infection, a prevalent cause of tropical diseases worldwide. Currently, no drugs are available for...
Approximately 3.9 billion individuals are vulnerable to dengue infection, a prevalent cause of tropical diseases worldwide. Currently, no drugs are available for preventing or treating Flavivirus diseases, including Dengue, West Nile, and the more recent Zika virus. The highly conserved Flavivirus NS2B-NS3 protease, crucial for viral replication, is a promising therapeutic target. This study employed in-silico methodologies to identify novel and potentially effective anti-dengue small molecules. A pharmacophore model was constructed using an experimentally validated NS2B-NS3 inhibitor, with the Gunner Henry score confirming the model's validity. The Natural Product Activity and Species Source (NPASS) database was screened using the validated pharmacophore model, yielding a total of 60 hits against the NS2B-NS3 protease. Furthermore, the docking finding reveals that our newly identified compounds from the NPASS database have enhanced binding affinities and established significant interactions with allosteric residues of the target protein. MD simulation and post-MD analysis further validated this finding. The free binding energy was computed in terms of MM-GBSA analysis, with the total binding energy for compound 1 (-57.3 ± 2.8 and - 52.9 ± 1.9 replica 1 and 2) indicating a stronger binding affinity for the target protein. Overall, this computational study identified these compounds as potential hit molecules, and these findings can open up a new avenue to explore and develop inhibitors against Dengue virus infection.
Topics: Viral Nonstructural Proteins; Dengue Virus; Molecular Docking Simulation; Serine Endopeptidases; Molecular Dynamics Simulation; Antiviral Agents; Protease Inhibitors; Drug Evaluation, Preclinical; Protein Binding; Viral Proteases
PubMed: 38834129
DOI: 10.1016/j.ijbiomac.2024.132855 -
Frontiers in Veterinary Science 2024The natural transmission cycle of West Nile virus (WNV) involves birds as primary hosts and mosquitoes as vectors, but this virus can spread to mammals, human beings...
The natural transmission cycle of West Nile virus (WNV) involves birds as primary hosts and mosquitoes as vectors, but this virus can spread to mammals, human beings included. Asymptomatic infected donors pose a risk to the safety of blood transfusions and organ transplants, as WNV can be transmitted through these medical procedures. Since 2009, the region of Emilia-Romagna in northern Italy has been implementing an integrated surveillance system in order to detect WNV circulation in the environment at an early stage. Here we report the results of the two components of the surveillance system, the active testing of corvids and humans, and demonstrate that bird surveillance alone improves a surveillance system based solely on human case detection. As WNV risk reduction measures are applied on a provincial basis, we assessed the ability of this surveillance system component to detect virus circulation prior to the notification of the first human case for each province. Overall, 99 epidemic seasons were evaluated as a result of 11 years (2013-2023) of surveillance in the nine provinces of the region. In this period, 22,314 corvids were tested for WNV and 642 (2.9%) were found to be infected. WNV was generally first detected in birds in July, with sample prevalence peaks occurring between August and September. During the same period, 469 autochthonous human cases were notified, about 60% of which were reported in August. WNV was detected 79 times out of the 99 seasons considered. The virus was notified in birds 73 times (92.4%) and 60 times (75.9%) in humans. WNV was first or only notified in birds in 57 seasons (72.1%), while it was first or only notified in humans in 22 seasons (27.8%). Active surveillance in corvids generally allows the detection of WNV before the onset of human cases. Failure of virus detection occurred mainly in seasons where the number of birds tested was low. Our results show that active testing of a minimum of 3.8 corvids per 100 km provides a satisfactory timeliness in the virus detection, but for early detection of WNV it is crucial to test birds between mid-June and mid-August.
PubMed: 38818494
DOI: 10.3389/fvets.2024.1407271 -
Scientific Reports May 2024Insects often exhibit irruptive population dynamics determined by environmental conditions. We examine if populations of the Culex tarsalis mosquito, a West Nile virus...
Insects often exhibit irruptive population dynamics determined by environmental conditions. We examine if populations of the Culex tarsalis mosquito, a West Nile virus (WNV) vector, fluctuate synchronously over broad spatial extents and multiple timescales and whether climate drives synchrony in Cx. tarsalis, especially at annual timescales, due to the synchronous influence of temperature, precipitation, and/or humidity. We leveraged mosquito collections across 9 National Ecological Observatory Network (NEON) sites distributed in the interior West and Great Plains region USA over a 45-month period, and associated gridMET climate data. We utilized wavelet phasor mean fields and wavelet linear models to quantify spatial synchrony for mosquitoes and climate and to calculate the importance of climate in explaining Cx. tarsalis synchrony. We also tested whether the strength of spatial synchrony may vary directionally across years. We found significant annual synchrony in Cx. tarsalis, and short-term synchrony during a single period in 2018. Mean minimum temperature was a significant predictor of annual Cx. tarsalis spatial synchrony, and we found a marginally significant decrease in annual Cx. tarsalis synchrony. Significant Cx. tarsalis synchrony during 2018 coincided with an anomalous increase in precipitation. This work provides a valuable step toward understanding broadscale synchrony in a WNV vector.
Topics: Animals; Mosquito Vectors; West Nile virus; Culex; Temperature; West Nile Fever; Population Dynamics; Climate; Seasons
PubMed: 38816487
DOI: 10.1038/s41598-024-62384-6 -
MMWR. Morbidity and Mortality Weekly... May 2024
Topics: Humans; United States; West Nile Fever; Arbovirus Infections; Disease Notification; Adult
PubMed: 38814815
DOI: 10.15585/mmwr.mm7321a2 -
Journal of Virology May 2024Live-attenuated flavivirus vaccines confer long-term protection against disease, but the design of attenuated flaviviruses does not follow a general approach. The... (Review)
Review
Live-attenuated flavivirus vaccines confer long-term protection against disease, but the design of attenuated flaviviruses does not follow a general approach. The non-coding, subgenomic flavivirus RNA (sfRNA) is produced by all flaviviruses and is an essential factor in viral pathogenesis and transmission. We argue that modulating sfRNA expression is a promising, universal strategy to finetune flavivirus attenuation for developing effective flavivirus vaccines of the future.
PubMed: 38808973
DOI: 10.1128/jvi.00100-23 -
The Medical Journal of Australia Jun 2024To investigate the distribution and prevalence of Japanese encephalitis virus (JEV) antibody (as evidence of past infection) in northern Victoria following the 2022...
OBJECTIVES
To investigate the distribution and prevalence of Japanese encephalitis virus (JEV) antibody (as evidence of past infection) in northern Victoria following the 2022 Japanese encephalitis outbreak, seeking to identify groups of people at particular risk of infection; to investigate the distribution and prevalence of antibodies to two related flaviviruses, Murray Valley encephalitis virus (MVEV) and West Nile virus Kunjin subtype (KUNV).
STUDY DESIGN
Cross-sectional serosurvey (part of a national JEV serosurveillance program).
SETTING
Three northern Victorian local public health units (Ovens Murray, Goulburn Valley, Loddon Mallee), 8 August - 1 December 2022.
PARTICIPANTS
People opportunistically recruited at pathology collection centres and by targeted recruitment through community outreach and advertisements. People vaccinated against or who had been diagnosed with Japanese encephalitis were ineligible for participation, as were those born in countries where JEV is endemic.
MAIN OUTCOME MEASURES
Seroprevalence of JEV IgG antibody, overall and by selected factors of interest (occupations, water body exposure, recreational activities and locations, exposure to animals, protective measures).
RESULTS
813 participants were recruited (median age, 59 years [interquartile range, 42-69 years]; 496 female [61%]); 27 were JEV IgG-seropositive (3.3%; 95% confidence interval [CI], 2.2-4.8%) (median age, 73 years [interquartile range, 63-78 years]; 13 female [48%]); none were IgM-seropositive. JEV IgG-seropositive participants were identified at all recruitment locations, including those without identified cases of Japanese encephalitis. The only risk factors associated with JEV IgG-seropositivity were age (per year: prevalence odds ratio [POR], 1.07; 95% CI, 1.03-1.10) and exposure to feral pigs (POR, 21; 95% CI, 1.7-190). The seroprevalence of antibody to MVEV was 3.0% (95% CI, 1.9-4.5%; 23 of 760 participants), and of KUNV antibody 3.3% (95% CI, 2.1-4.8%; 25 of 761).
CONCLUSIONS
People living in northern Victoria are vulnerable to future JEV infection, but few risk factors are consistently associated with infection. Additional prevention strategies, including expanding vaccine eligibility, may be required to protect people in this region from Japanese encephalitis.
Topics: Humans; Cross-Sectional Studies; Encephalitis Virus, Japanese; Middle Aged; Seroepidemiologic Studies; Encephalitis, Japanese; Adult; Female; Male; Antibodies, Viral; Aged; Victoria; Disease Outbreaks; Immunoglobulin G; Young Adult; Encephalitis Virus, Murray Valley; Adolescent; Risk Factors
PubMed: 38803004
DOI: 10.5694/mja2.52344 -
Wellcome Open Research 2024is an invasive mosquito species with an extensive and expanding inter-continental distribution, currently reported across Asia, Africa, the Middle East, Europe and now...
BACKGROUND
is an invasive mosquito species with an extensive and expanding inter-continental distribution, currently reported across Asia, Africa, the Middle East, Europe and now Australia. It is an important vector of medical and veterinary pathogens which cause significant morbidity and mortality in human and animal populations. Across regions endemic for Japanese encephalitis virus (JEV), is considered the major vector and has also been shown to contribute to the transmission of several other zoonotic arboviruses including Rift Valley fever virus (RVFV) and West Nile virus (WNV).
METHODS
In this study, we used laboratory vector competence experiments to determine if from a Southern European population were competent JEV vectors. We also obtained samples from multiple geographically dispersed populations from countries within Europe, Africa, Eurasia and Asia to perform phylogenetic analysis to measure the level of mitochondrial divergence using the ( ) gene. We also undertook bacterial gene amplicon sequencing to determine microbial diversity and used multi-locus sequence typing (MLST) to determine any evidence for the presence of strains of the naturally occurring endosymbiotic bacterium .
RESULTS
from a Greek population were shown be be competent vectors of JEV with high levels of virus present in saliva. We found a signficant level of mitochondrial genetic diversity using the mosquito gene between geographically dispersed populations. Furthermore, we report diverse microbiomes identified by gene amplicon sequencing within and between geographical populations. Evidence for the detection of the endosymbiotic bacteria was confirmed using -specific PCR and MLST.
CONCLUSIONS
This study enhances our understanding of the diversity of and the associated microbiome across its inter-continental range and highlights the need for greater surveillance of this invasive vector species in Europe.
PubMed: 38800519
DOI: 10.12688/wellcomeopenres.20761.1