Culex Vishnui Research Articles

Molecular Identification of Species Belonging to Culex vishnui Subgroup (Diptera: Culicidae), Vectors of Japanese Encephalitis Virus, in Taiwan.

Classification of mosquitoes with overlapping features remains problematic when using traditional morphological identification alone. In this study, we used molecular methods to elucidate the taxonomic status of Culex tritaeniorhynchus, Culex annulus, and Culex pseudovishnui species as vectors of the Japanese encephalitis virus belonging to the Culex vishnui subgroup and gene flow among them. In this study, 76, 59, and 3 samples of Cx. annulus, Cx. tritaeniorhynchus, and Cx. pseudovishnui, respectively, were collected around Taiwan. Phylogenetic analysis and genetic divergence were based on genomic sequence variations in ribosomal DNA and the internal transcribed spacer (rDNA) and cytochrome c oxidase subunit I (COI). Our results revealed that Cx. annulus and Cx. vishnui are genetically similar and share a gene pool among the species from Taiwan and other Asian countries. However, two hidden taxa of Cx. tritaeniorhynchus, which clustered together according to the rDNA sequences, were discovered based on the COI sequences. In addition, Cx. pseudovishnui has different gene pools from those of the strains from other countries, implying that the population from Taiwan is probably either a unique strain or a sibling species. This study provides molecular information on the taxonomic status of the species in the Cx. vishnui subgroup in Taiwan and gene flow between these species, providing valuable information for vector control operations and the delineation of the evolutionary process.

Updated checklist with new records and molecular data for the mosquitoes (Diptera: Culicidae) of Hong Kong.

An extensive mosquito survey was carried out in Hong Kong from September to October 2022, employing a variety of collection methods. Specimens were identified using a combination of morphology and mitochondrial cytochrome C oxidase subunit 1 (COI) barcode sequences. Twenty-nine species, including three new records, i.e., Culex bicornutus (Theobald), Culex cinctellus Edwards, and Lutzia chiangmaiensis Somboon & Harbach, were collected. Phylogenetic analysis of COI sequences of Culex annulus Theobald and Culex vishnui Theobald collected in Hong Kong and elsewhere revealed that the sequences of the two nominal species are genetically very similar and are included in the same clade. Consequently, the synonymy of Cx. annulus with Cx. vishnui is reinstated. Lutzia halifaxii (Theobald) is removed from the list of species in Hong Kong and is replaced with Lutzia vorax Edwards, the identification of which is confirmed in the present study. The record of Culex spiculothorax Bram recorded in Hong Kong is replaced with the senior synonym Culex sasai Kano, Nitahara & Awaya. The occurrence of Anopheles fluviatilis James and Aedes aegypti (Linnaeus) is discussed. Finally, an updated checklist of the mosquitoes of Hong Kong, which now includes 76 species representing 14 genera, is provided, with notation of those species that vector pathogens of human diseases.

Larvicidal efficacy of Diospyros kaki fruit extracts against Culex Vishnui mosquito

Larvicidal efficacy of Diospyros kaki fruit extracts against Culex Vishnui mosquito

Seasonal species composition, abundance and public health importance of mosquito vectors (Diptera: Culicidae) in Huai Tha Khoei Reservoir, Ratchaburi, Thailand

Abstract. Chaiphongpachara T, Laojuna S. 2024. Seasonal species composition, abundance and public health importance of mosquito vectors (Diptera: Culicidae) in Huai Tha Khoei Reservoir, Ratchaburi, Thailand. Biodiversitas 25: 1264-1275. Mosquitoes are vectors for pathogens that cause life-threatening diseases in humans and animals. Significant mosquito-borne diseases include malaria, dengue, chikungunya, Zika, Japanese encephalitis, and filariasis. Anthropogenic environmental changes can significantly impact the dynamics of disease vector populations, which can lead to outbreaks of mosquito-borne diseases. This study investigated the seasonal variation in species composition and abundance of mosquito vectors around the Huai Tha Khoei Reservoir in Ratchaburi Province, Thailand, across cool, hot, and rainy seasons. A total of 1363 mosquitoes, representing 30 species from five genera, were collected. In particular, 25 of these species, accounting for 83.33% of the total, were identified as vectors of human pathogens. The most dominant species across all seasons was Culex tritaeniorhynchus Giles 1901, representing 39.47% (n=538) of the total, followed by Anopheles barbirostris Wulp 1884 s.l. (14.38%, n = 196) and Culex vishnui Theobald 1901 (9.02%, n=123). The Shannon diversity index was highest during the rainy season (H’= 2.144) and lowest in the hot season (H’=1.788). This is consistent with the results of the UPGMA tree based on beta diversity, indicating that mosquito diversity in the rainy season differs significantly from that in the cool and hot seasons. The findings enhance our understanding of the impact of seasonality on mosquito vectors in this region, which is crucial for developing effective disease control strategies. Additionally, this study serves as a valuable reference for understanding the diversity of mosquito vectors in other areas.

Characterization of the complete mitochondrial genome of Culex vishnui (Diptera: Culicidae), one of the major vectors of Japanese encephalitis virus.

Culex mosquitoes (Diptera: Culicidae) can transmit a variety of arthropod-borne viruses (arboviruses), causing human and animal diseases. Cx. vishnui, Cx. pseudovishnui, and Cx. tritaeniorhynchus are three representative species in Culex vishnui subgroup, which are widely distributed in southeast Asia, and they have been proved as the main vectors transmitting Japanese encephalitis virus (JEV) that could cause human infectious mosquito-borne disease across Asia. However, the epidemiology, biology, and even molecular information of those mosquitos remain poorly understood, and only the mitochondrial genome (mitogenome) of Cx. tritaeniorhynchus has been reported in these species. In the present study, we sequenced and annotated the complete mitogenome sequence of Cx. vishnui which was 15,587bp in length, comprising 37 genes. Comparisons of nucleotide and amino acid sequences between Cx. vishnui and Cx. tritaeniorhynchus revealed that most genes within Culex vishnui subgroup were conserved, except atp8, nad1, atp6, and nad6, with differences of 0.4 (rrnS) - 15.1% (tRNAs) and 0 (nad4L) - 9.4% (atp8), respectively, interestingly suggesting the genes nad4L and rrnS were the most conserved but atp8 gene was the least. The results based on nucleotide diversity also supported a relatively uniform distribution of the intraspecific differences in Cx. vishnui and Cx. tritaeniorhynchus with only one highly pronounced peak of divergence centered at the control region. Phylogenetic analyses using concatenated amino acid sequences of 13 protein-coding genes supported the previous taxonomic classification of the family Culicidae and the monophyly of tribes Aedini, Culicini, Mansoniini, and Sabethini. The present study revealed detailed information on the subgroup Culex vishnui, reanalyzed the relationships within the family Culicidae, provided better markers to identify and distinguish Culex species, and offered more markers for studying the molecular epidemiology, population genetics, and molecular phylogenetics of Cx. vishnui.

Species Identification of the Major Japanese Encephalitis Vectors within the Culex vishnui Subgroup (Diptera: Culicidae) in Thailand Using Geometric Morphometrics and DNA Barcoding

Japanese encephalitis (JE) is a viral infection of the brain caused by the Japanese encephalitis virus, which spreads globally, particularly in 24 countries of Southeast Asia and the Western Pacific region. In Thailand, the primary vectors of JE are Cx. pseudovishnui, Cx. tritaeniorhynchus, and Cx. vishnui of the Cx. vishnui subgroup. The morphologies of three mosquito species are extremely similar, making identification challenging. Thus, geometric morphometrics (GM) and DNA barcoding were applied for species identification. The results of cross-validation reclassification revealed that the GM technique based on wing shape analysis had relatively high potential for distinguishing Cx. pseudovishnui, Cx. tritaeniorhynchus, and Cx. vishnui (total performance = 88.34% of correctly assigned individuals). While the DNA barcoding yielded excellent results in identifying these Culex species based on the DNA barcode gap (average intraspecific genetic distance = 0.78% ± 0.39% and average interspecific genetic distance = 6.14% ± 0.79%). However, in the absence of the required facilities for DNA barcoding, GM techniques can be employed in conjunction with morphological methods to enhance the reliability of species identification. Based on the results of this study, our approach can help guide efforts to identify members of the Cx. vishnui subgroup, which will be useful for the effective vector control of JE in Thailand.

Chemical characterization of n-alkane compounds in the leaves of Holoptelea integrifolia and its repellence against Japanese encephalitis vector

Epicuticular wax extract bearing n-alkane compounds were isolated from leaves of Holoptelea integrifolia and its chemical characterization was done by GC-MS analysis. Seven n-alkane compounds were isolated from epicuticular wax of H. integrifolia, which are Undecane [C11H24], Decane 5-methyl- [C11H24], Dodecane [C12H26], Undecane, 3,6-dimethyl- [C12H26], Hexadecane, 2,6,10,14-tetramethyl- [C20H42], Tridecane [C13H28], and Tetradecane [C14H30]. Different concentrations of crude extract as well as epicuticular wax extract bearing n-alkane each @ 2, 4 and 5 ppm cm-2 applied on human hand surface for repellence against Culex vishnui (vectors of JE) and at different time of exposure, gave a maximum protection of 73.33 per cent in the case of crude extract, and 94.33 per cent with epicuticular wax extract, both at 5 ppm cm-2, up to five hours of exposure.

Molecular characterization and genetic divergence of seven Culex mosquito (Diptera: Culicidae) species using Mt COI gene from Odisha State, India

BackgroundCulex mosquitoes are involved in the transmission of arboviral diseases worldwide. Bio-ecology and identification of mosquitoes are of paramount importance to develop species-specific vector control strategies. Genetic-based species-specific approaches that reduce the burden of vector-borne diseases are made possible by molecular techniques.ResultsIn the present study, the mitochondrial COI gene of Culex mosquitoes was used for molecular identification in addition to morpho-taxonomy. Our findings suggested the presence of important Culex mosquito vectors viz, Culex vishnui, Culex tritaeniorhynchus, Culex bitaeniorhynchus, Culex quinquefasciatus, Culex gelidus, Culex fuscocephala, and Culex fuscanus in the southern part of Odisha state, India. We examined the phylogeny and genetic diversity of the above seven different Culex populations from different geographical locations. An average intra-specific K2P distance of the COI gene was found to be 0.9%. Further, to measure the diversity of the Culex population among different geographical strains, haplotype diversity and nucleotide diversity were compared. Culex fuscanus showed high polymorphisms and mutations with high nucleotide diversity (0.013) and the Culex quinquefasciatus showed the lowest variation in P(i), 0.0013 in the intra-population polymorphism analysis of COI sequences. Similarly, the Haplotype diversity (Hd) found in Culex gelidus and Culex fuscocephala with the value of 0.972 and Culex quinquefasciatus (0.583) showed the lowest value of haplotype diversity. A haplotype network was constructed to establish the genealogical relationship between haplotypes. The phylogenetic tree was constructed that produces distinctive conspecific clusters in different Culex species. Population genetic study has illustrated the occurrence of genetic differentiation within the population.ConclusionsThe findings of this study contribute to greater evidence that DNA barcode sequences can be used to monitor mosquito species diversity. This study also adds valuable information about the systematics and molecular biology of seven public health important mosquito species acting as a significant vector for Japanese encephalitis in various Asian continents. This information is further used for the effective implementation of region-specific vector control strategies.

UV Light-Emitting-Diode Traps for Collecting Nocturnal Biting Mosquitoes in Urban Bangkok

Simple SummaryThis study was conducted to evaluate the efficacy of six ultraviolet light-emitting diodes (UV-LED) traps and a fluorescent light trap for sampling urban nocturnal mosquitoes. Results demonstrated that the fluorescent light trap outperformed all the UV-LED traps throughout the 72 sampling nights and between wet and dry seasons. Among the UV-LED traps, the LED375 trapped the highest number of mosquitoes. Additional field trials are needed to validate these findings in different ecological settings.Well-designed surveillance systems are required to facilitate a control program for vector-borne diseases. Light traps have long been used to sample large numbers of insect species and are regarded as one of the standard choices for baseline insect surveys. The objective of this study was to evaluate the efficacy of six ultraviolet light-emitting diodes and one fluorescent light for trapping urban nocturnal mosquito species within the Kasetsart University (KU), Bangkok. Ultraviolet light-emitting diodes (UV-LEDs), (LED365, LED375, LED385, LED395, and LED405) and a fluorescent light were randomly assigned to six different locations around the campus in a Latin square design. The traps were operated continuously from 18:00 h to 06:00 h throughout the night. The traps were rotated between six locations for 72 collection-nights during the dry and wet seasons. In total, 6929 adult mosquitoes were caught, with the most predominant genus being Culex, followed by Aedes, Anopheles, Armigeres and Mansonia. Among the Culex species, Culex quinquefasciatus (n = 5121: 73.9%) was the most abundant followed by Culex gelidus (n = 1134: 16.4%) and Culex vishnui (n = 21: 0.3%). Small numbers of Aedes, Armigeres, and Anopheles mosquitoes were trapped [Aedes albopictus (n = 219: 3.2%), Aedes pocilius (n = 137: 2.0%), Armigeres subalbatus (n = 97: 1.4%), Anopheles vagus (n = 70: 1.0%), Aedes aegypti (n = 23: 0.3%)]. There were 2582 specimens (37.2%) captured in fluorescent light traps, whereas 942 (13.6%), 934 (13.5%), 854 (12.3%), 820 (11.8%), and 797 (11.5%) were captured in the LED375, LED405, LED395, LED365, and LED385 traps, respectively. None of the UV-LED light traps were as efficacious for sampling nocturnal mosquito species as the fluorescent light trap. Among the five UV-LED light sources, LED375 trapped the greatest number of mosquitoes. Additional field trials are needed to validate these findings in different settings in order to substantially assess the potential of the LEDs to trap outdoor nocturnal mosquitoes.

Mosquito (Diptera: Culicidae) diversity and medical importance in Koh Kong mangrove forests, Cambodia.

Mangroves are an ecosystem interface between land and sea, forming distinctive shallow-water marine communities in tropical and subtropical waters. The mangrove forest surface in Cambodia is being reduced due to deforestation. Because the mangrove type of ecosystem generally hosts a great diversity of mosquitoes, the urbanization of these ecosystems will increase interactions between humans and wild mosquitoes, and might thus serve as a potential source of new infectious diseases. Understanding mosquito diversity and analyzing their virome is critical to estimate the risk of emergence or future outbreaks of mosquito-borne diseases. To understand the mosquito diversity of mangrove forests of Koh Kong province (Cambodia). In 2019, the mosquito fauna was sampled for 3 consecutive days using BG-Sentinel and light traps, in 3 locations in the mangrove forests of Koh Kong province (Cambodia) during both dry and rainy seasons. A total of 3107 samples were collected, belonging to 10 genera for 34 species. The Culex genus was the most diverse, accounting for 10 species. One species, Culex sitiens, represented over 60% of all collected mosquitoes. A total of 12 medically important species were recorded, 2 species, Aedes (Stegomyia) albopictus and Culex vishnui, were collected in all sites and during both the dry and rainy seasons, highlighting a potential risk of these species acting as bridge vectors. If new arboviruses were to be recorded in this peculiar area, it would indicate that the mosquito species found have the potential to act as a bridge between sylvatic and anthropogenic arboviruses.

Culex vishnui (Diptera: Culicidae): An Overlooked Vector of Arboviruses in South-East Asia.

Culex vishnui Theobald, 1901, a main vector of Japanese encephalitis virus (JEV), is widely distributed in the Oriental region where it often accounts for a great part of the culicid fauna. This species also has been found naturally infected with at least 13 other arboviruses of medical and veterinary importance. Females blood feed predominantly upon pigs and birds, but may readily bite cattle and humans. Because of its abundance, medical importance, and presence throughout ecological gradients among urban, peri-urban, and rural areas, Cx. vishnui potentially may serve as a bridge vector transmitting viruses from natural and wild hosts to humans. Being zoo- and anthropophagic, omnipresent in the Oriental region, and presenting strong resistance to many insecticide families, this overlooked mosquito species may pose a serious health risk in one of the most densely populated regions of the world.

Identification of potential vectors of Dirofilaria immitis and Brugia pahangi (Spirurida: Filariidae): First observation of infective third-stage larva of B. pahangi in Culex quinquefasciatus (Diptera: Culicidae)

ABSTRACT Information on the mosquito species that transmit canine filariosis is scanty. Hence, an experimental study was conducted to identify the potential vectors responsible for the transmission of D. immitis Leidy and B. pahangi Buckley & Edeson. A total of 367 mosquitoes belonging to six species containing both laboratory and field strains (i.e. Aedes togoi Theobald, Aedes aegypti Linnaeus, Aedes albopictus Skuse, Culex quinquefasciatus Say, Culex vishnui Theobald and Anopheles dirus Peyton & Harrison) were used in this study. All mosquitoes were artificially fed on either D. immitis or B. pahangi microfilariae (mfs) infected blood by using the Hemotek™ membrane feeding system. Out of 367 mosquitoes, 228 (64.9%) were fully engorged. After feeding on D. immitis (20%) and B. pahangi (33%) mfs positive blood, the mortality rates for Cx. quinquefasciatus were found to be slightly lower than that of other species of mosquitoes. On the other hand, majority of An. dirus were found to be incapable to withstand the infection of mfs as the mortality rates were relatively high (D. immitis = 71.4%; B. pahangi = 100.0%). Brugia pahangi was detected in Ae. togoi and Cx. quinquefasciatus with infection rates of 50% and 25%, respectively. Aedes togoi was the only species infected with D. immitis with an infection rate of 69%. Our results showed that Ae. togoi was an excellent experimental vector for both D. immitis and B. pahangi. This study also documented the observation of B. pahangi, for the first time in the head region of Cx. quinquefasciatus under a laboratory setting.

Mosquito diversity (Diptera: Culicidae) and medical importance, in a bird sanctuary inside the flooded forest of Prek Toal, Cambodia

• Twenty five species of mosquitoes were collected. • Culex vishnui represents 58.8% of all collected mosquitoes. • Thirteen medically important species are present. • Six species could be considered as bridge vectors. Wild birds have been identified as reservoirs of many pathogens transmissible to humans through bird-biting mosquitoes. Understanding the diversity of vector fauna in bird-conservation areas, is a cornerstone to later develop early detection systems and reduce the risk of emerging disease incidence. Prek Toal is a bird Sanctuary in the Tonle-Sap area in Cambodia hosting the largest migratory bird colony of southeast Asia. The Culicidae fauna was investigated during both dry and rainy seasons. In total, 8,224 mosquitoes from 6 genera and 25 species were collected. The two most represented genera were Anopheles (8 species) and Culex (11 species), while the dominant species was Culex vishnui (58.8%). During the rainy season, 1.6 fold more mosquitoes were caught and the number of species doubled. One of the most notable feature is the absence of any Aedinii mosquito which could be attributed to the low human density around the area, and the large populations of migratory birds. A total of 13 species from 3 genera are reported to be of medical importance. 6 medically-important species were collected in all 3 sites, and are known to bite both wild birds and humans: An. barbirostris , An. campestris , Cx. bitaeniorhynchus , Cx. vishnui , Ma. indiana and Ma. uniformis . One of the most important feature is the over-abundance of Culex vishnui , largely dominant in Prek Toal throughout the seasons and the sites, and being present everywhere in Cambodia. This finding stresses its potentiality to act as bridge vectors in the case of new disease emergence.

Identification and Isolation of Japanese Encephalitis Virus Genotype IV from Culex vishnui Collected in Bali, Indonesia in 2019.

Japanese encephalitis virus (JEV) is transmitted between swine, migratory birds, and Culex mosquitoes, and has circulated indigenously in Asia for almost a century. Despite being the country with the highest JEV diversity, surveillance targeting of Indonesia's vectors is scarce. This study collected mosquitoes from several locations in Tabanan Regency, Bali Island, Indonesia. We captured and classified 3,032 adult Culex mosquitoes into seven species, with Culex vishnui subgroup mosquitoes making up approximately 90% of the total. Japanese encephalitis virus was identified by next-generation sequencing (NGS) analysis of a Cx. vishnui mosquito pool. Genetic and phylogenetic analysis revealed the JEV as genotype (G) IV. The nucleotide identity was 99% with other JEV GIV isolates obtained from swine sera in 2017 on Bali Island and from a human patient in Australia with a travel history to Bali in 2019. This finding indicated that JEV GIV persists in restricted areas and is circulating between swine-mosquito vectors.

Aedes aegypti as potential vector of filariasis in Pekalongan, Central Java Province, Indonesia

Background: The filariasis elimination program in Indonesia has been conducted, but new cases and some chronic cases are still often found. Objective: This study aims to determine levels of endemicity and to identify filarial worm species in filariasis cases and s and their surrounding communities by using microscopic examination, polymerase chain reaction (PCR), and to examine levels of infection in vectors mosquito by surgery and PCR. Also to to determine that Ae. aegypti can act as vector of filariasis. Methods: This study was conducted at 10 locations in Pekalongan Regency, Central Java Province, with a cross sectional design. Intravenous blood sampling was conducted on 102 respondents consisting of 10 elephantiasis patients and 92 non-elephantiasis patients at night, starting at 8 pm, then examined microscopically and PCR. Mosquitoes in this study were collected by using a human landing collection method for 12 hours from 6 pm to 6 am by volunteers. Artificial infection of microfilaria W. bancrofti was held against Cx. quinquefasciatus and Ae.aegypti from laboratory collection. Results: Results of this study found that there were 5.729 of mosquitos, consisting of 8 species, namely Culex quinquefasciatus, Culex vishnui, Culex tritaeniorhynchus, Aedes aegypti, Aedes albopictus, Anopheles subpictus, Anopheles vagus, and Armigeres kesseli. Microfilarial (mf) rate was 0.89%, and and the blood PCR showed infection rate of 3.92% and the blood PCR showed infection rate of 3.92%. No larva was found in female mosquito dissection. The PCR results showed that the infection rate was 9.10% in Ae. aegypty pool respectively. Artificial infection results was negative both dissecting microscopis and PCR. Conclusion: This study revealed that the locations were low of filariasis endemicity. The mf rate was less than 1%, and there was a moderate density to high density of microfilaria in the patients. The low level of infection rates in mosquito is suggested as an alert to its potential transmission.

Shape relatedness between geographic populations of Culex tritaeniorhynchus, the primary vector of Japanese encephalitis virus: A landmark study

Japanese encephalitis is a severe disease of acute encephalitis, with children and the elderly primarily affected, and with mortality rates reaching over 25%. The virus is transmitted mainly by species of the Culex (Culex) vishnui subgroup, primarily the widely spread Cx. tritaeniorhynchus Giles. The latter is known as a highly migratory mosquito which moves with airflow over large distances. We explored the geometric variation of the wing venation among distant areas of its geographic distribution. Our working hypothesis was that shape variation across geography could reveal known past and present migratory routes. We compared the wing venation geometry of 236 female Culex tritaeniorhynchus from different locations in the Madagascan (La Reunion), Oriental (Thailand, Vietnam) and Paleartic (Japan) regions. To ascertain the taxonomic signal of the wing venation we also used two species as relative outgroups, Cx. whitmorei and Cx. brevipalpis. In spite of an increasing morphometric variation as expected with larger geographic dispersion, our Cx. tritaeniorhynchus samples were clustered as a single species when considered relative to other Culex species. The relationships between geographic sites of Cx. tritaeniorhynchus globally conformed with an isolation by distance model. The shape homogeneity of our Palearctic samples (Japan) contrasted with some heterogeneity observed in the Oriental region (Thailand, Vietnam), and could be related to the different regimes of wind trajectories in these regions. The average shape variation of Culex tritaeniorhynchus disclosed a separation between Madagascan, Oriental and Palearctic regions in accordance with geography. The wing venation not only could reflect geography, it also contained a clear taxonomic signal separating three Culex species. Within Cx. tritaeniorhynchus, a contrasting pattern of shape variation between the Palearctic and the Oriental regions is tentatively explained by the influence of wind trajectories.

Natural Wolbachia infection in field-collected Anopheles and other mosquito species from Malaysia

BackgroundThe endosymbiont bacterium Wolbachia is maternally inherited and naturally infects some filarial nematodes and a diverse range of arthropods, including mosquito vectors responsible for disease transmission in humans. Previously, it has been found infecting most mosquito species but absent in Anopheles and Aedes aegypti. However, recently these two mosquito species were found to be naturally infected with Wolbachia. We report here the extent of Wolbachia infections in field-collected mosquitoes from Malaysia based on PCR amplification of the Wolbachia wsp and 16S rRNA genes.MethodsThe prevalence of Wolbachia in Culicinae mosquitoes was assessed via PCR with wsp primers. For some of the mosquitoes, in which the wsp primers failed to amplify a product, Wolbachia screening was performed using nested PCR targeting the 16S rRNA gene. Wolbachia sequences were aligned using Geneious 9.1.6 software, analyzed with BLAST, and the most similar sequences were downloaded. Phylogenetic analyses were carried out with MEGA 7.0 software. Graphs were drawn with GraphPad Prism 8.0 software.ResultsA total of 217 adult mosquitoes representing 26 mosquito species were screened. Of these, infections with Wolbachia were detected in 4 and 15 mosquito species using wsp and 16S rRNA primers, respectively. To our knowledge, this is the first time Wolbachia was detected using 16S rRNA gene amplification, in some Anopheles species (some infected with Plasmodium), Culex sinensis, Culex vishnui, Culex pseudovishnui, Mansonia bonneae and Mansonia annulifera. Phylogenetic analysis based on wsp revealed Wolbachia from most of the mosquitoes belonged to Wolbachia Supergroup B. Based on 16S rRNA phylogenetic analysis, the Wolbachia strain from Anopheles mosquitoes were more closely related to Wolbachia infecting Anopheles from Africa than from Myanmar.ConclusionsWolbachia was found infecting Anopheles and other important disease vectors such as Mansonia. Since Wolbachia can affect its host by reducing the life span and provide resistance to pathogen infection, several studies have suggested it as a potential innovative tool for vector/vector-borne disease control. Therefore, it is important to carry out further studies on natural Wolbachia infection in vector mosquitoes’ populations as well as their long-term effects in new hosts and pathogen suppression.

Keanekaragaman Spesies Nyamuk di Daerah Transmission Assesment Survey (TAS) Filariasis di Kabupaten Enrekang, Provinsi Sulawesi Selatan

Enrekang Regency was declared to have passed third Transmission Assesment Survey (TAS), since there were no positive Brugia Malayi in elementary school students. The aspect of filariasis vector must be considered in this disease transmission. This study aims to determine the diversity of mosquitoes and their potential as vectors of filariasis in the TAS area in Enrekang Regency, South Sulawesi Province. This research is part of a multicenter study in 2017. This study was conducted with a cross-sectional study. Mosquitoes were collected in Parombean Village and Potokulin Village by modifying the Human Landing Catches (HLC) method with the human-baited double net trap from 18:00 to 06:00. The results showed that 30 species found in Parombean Village, consisted eight genera and Culex vishnui was the most abundant species. In Potokulin Village, 11 species were found consisted in five genera and Cx. quinquefasciatus was the most abundant species. The average age of mosquitoes was around 8-24 days. The species of mosquito as vector potential of filariasis in this area is Cx. vishnui, Cx, quinquefasciatus, and Anopheles barbirostris.

Deciphering the Virome of Culex vishnui Subgroup Mosquitoes, the Major Vectors of Japanese Encephalitis, in Japan.

Japanese encephalitis (JE) remains a public health concern in several countries, and the Culex mosquito plays a central role in its transmission cycle. Culex mosquitoes harbor a wide range of viruses, including insect-specific viruses (ISVs), and can transmit a variety of arthropod-borne viruses (arboviruses) that cause human and animal diseases. The current trend of studies displays enhanced efforts to characterize the mosquito virome through bulk RNA sequencing due to possible arbovirus–ISV interactions; however, the extent of viral diversity in the mosquito taxon is still poorly understood, particularly in some disease vectors. In this study, arboviral screening and RNA virome analysis of Culex tritaeniorhynchus and C. pseudovishnui, which are part of the Culex vishnui subgroup mosquitoes, were performed. Results from these two mosquito species, known as the major vectors of JE virus (JEV) in Asia, collected in three prefectures in Japan were also compared with the sympatric species C. inatomii. A total of 27 viruses, including JEV, were detected from these Culex mosquitoes. Molecular and phylogenetic analyses of the detected viruses classified 15 of the 27 viruses as novel species, notably belonging to the Flaviviridae, Rhabdoviridae, Totiviridae, and Iflaviridae families. The successful isolation of JEV genotype I confirmed its continuous presence in Japan, suggesting the need for periodic surveillance. Aside from JEV, this study has also reported the diversity of the RNA virome of disease vectors and broadened the knowledge on mosquito virome profiles containing both arbovirus and ISV. Mosquito taxon seemed to contribute largely to the virome structure (e.g., virome composition, diversity, and abundance) as opposed to the geographical location of the mosquito species. This study therefore offers notable insights into the ecology and evolution of each identified virus and viral family. To the authors’ knowledge, this is the first study to characterize the viromes of the major JE vectors in Japan.

Seasonal Prevalence of Japanese Encephalitis (JE) in Patna District of Bihar, India

Background: Japanese Encephalitis (JE) is a major upcoming health problem in Bihar, India. JE is considered in the group of Acute Encephalitis Syndrome (AES) taking toll of pediatric age group every year in Bihar. The pattern of transmission of the disease in new areas based on seasonality is needed to be investigate. Methods: Sources of data collection of AES and JE were Patna Medical College and Hospital, Patna and Nalanda Medical College and Hospital Patna through State health Society, Bihar, Patna. The vector and sera samples of pigs were collected from endemic zone. The central tendency statistical method was applied for analysis of data. Result: In total 21 cases of AES were reported from two top-grade state hospitals at Patna like Patna Medical College Hospital and Nalanda Medical College Hospital in 2018. The cases were found prevalent throughout the year in 2018 between the temperature range of 5oC to 49oC and Relative humidity 11 to 100%. The number of patients was high under the age of ten. The Japanese Encephalitis Virus (JEV) was also detected from the pigs. Eight sera samples of pigs out of 10 were found positive for JEV collected from the affected areas. The disease transmitting vectors like Culex tritaeniorhynchus and Culex vishnui were present in the locality. The case fatality was found 6.7% in the case of JE. All cases were treated in the hospitals. Conclusion: The case fatality rate due to AES including JE was very high in Patna district. The cases of JE are appearing most of the months in the year. It is essential to scrutinize the cases in time and to implement the essential control measures to treat patient and to use insecticide to control vector to inhibit further transmission of the disease along with vaccination in due course of time. How to cite this article:Kumar P, Mishra R, Topno RK, Kumar M, Dinesh DS, Singh DK. Seasonal Prevalence of Japanese Encephalitis (JE) in Patna District of Bihar, India. J Commun Dis 2019; 51(4): 58-61. DOI: https://doi.org/10.24321/0019.5138.201937