Vector Biology Research Articles

Japanese Encephalitis in Assam: A Sentinel Case

Since times immemorial, mosquito borne diseases have proved to be a great menace to the human population. Their severe clinical manifestations and high mortality contribute to their deadly status. Japanese encephalitis (JE), is one such mosquito borne viral disease mainly prevalent in Southeast Asia including India, particularly in the state of Assam. It mainly affects the central nervous system, resulting in various neurological and locomotor disorders and change in mental status. Seizures are also observed, although they are more common in children. JE is caused by a virus of the Flaviviridae family, transmitted by a Culicine mosquito, Culex tritaeniorynchus. Pigs are considered to be the amplifier hosts. Throughout the years, JE has become endemic in many districts of Assam affecting many lives in the outbreaks that occur each year, more particularly in the rural and agricultural areas. Assam’s climactic conditions, agricultural habits and patterns, and the lifestyle of its population play a major role in the epidemiology of the disease. With the establishment of JE surveillance and vaccination programmes by the government, the JE incidence rate has decreased. However, outbreaks of JE still continue to occur, often with serious complications and a high mortality. This concise review article gives a short summarization of Japanese encephalitis along with its history, epidemiology, vector and host biology, pathology, clinical observations and immunoprophylaxis with respect to the state of Assam, India.

Biting midges (Diptera: Ceratopogonidae) as putative vectors of zoonotic Onchocerca lupi (Nematoda: Onchocercidae) in northern Arizona and New Mexico, southwestern United States.

Onchocerca lupi (Rodonaja, 1967) is an understudied, vector-borne, filarioid nematode that causes ocular onchocercosis in dogs, cats, coyotes, wolves, and is also capable of infecting humans. Onchocercosis in dogs has been reported with increasing incidence worldwide. However, despite the growing number of reports describing canine O. lupi cases as well as zoonotic infections globally, the disease prevalence in endemic areas and vector species of this parasite remains largely unknown. Here, our study aimed to identify the occurrence of O. lupi infected dogs in northern Arizona, New Mexico, and Utah, United States and identify the vector of this nematode. A total of 532 skin samples from randomly selected companion animals with known geographic locations within the Navajo Reservation were collected and molecularly surveyed by PCR for the presence of O. lupi DNA (September 2019-June 2022) using previously published nematode primers (COI) and DNA sequencing. O. lupi DNA was detected in 50 (9.4%) sampled animals throughout the reservation. Using positive animal samples to target geographic locations, pointed hematophagous insect trapping was performed to identify potential O. lupi vectors. Out of 1,922 insects screened, 38 individual insects and 19 insect pools tested positive for the presence of O. lupi, all of which belong to the Diptera family. This increased surveillance of definitive host and biological vector/intermediate host is the first large scale prevalence study of O. lupi in companion animals in an endemic area of the United States, and identified an overall prevalence of 9.4% in companion animals as well as multiple likely biological vector and putative vector species in the southwestern United States. Furthermore, the identification of these putative vectors in close proximity to human populations coupled with multiple, local zoonotic cases highlight the One Health importance of O. lupi.

Relationship between Climate Variables and Dengue Incidence in Argentina.

Climate change is an important driver of the increased spread of dengue from tropical and subtropical regions to temperate areas around the world. Climate variables such as temperature and precipitation influence the dengue vector's biology, physiology, abundance, and life cycle. Thus, an analysis is needed of changes in climate change and their possible relationships with dengue incidence and the growing occurrence of epidemics recorded in recent decades. This study aimed to assess the increasing incidence of dengue driven by climate change at the southern limits of dengue virus transmission in South America. We analyzed the evolution of climatological, epidemiological, and biological variables by comparing a period of time without the presence of dengue cases (1976-1997) to a more recent period of time in which dengue cases and important outbreaks occurred (1998-2020). In our analysis, we consider climate variables associated with temperature and precipitation, epidemiological variables such as the number of reported dengue cases and incidence of dengue, and biological variables such as the optimal temperature ranges for transmission of dengue vector. The presence of dengue cases and epidemic outbreaks are observed to be consistent with positive trends in temperature and anomalies from long-term means. Dengue cases do not seem to be associated with precipitation trends and anomalies. The number of days with optimal temperatures for dengue transmission increased from the period without dengue cases to the period with occurrences of dengue cases. The number of months with optimal transmission temperatures also increased between periods but to a lesser extent. The higher incidence of dengue virus and its expansion to different regions of Argentina seem to be associated with temperature increases in the country during the past two decades. The active surveillance of both the vector and associated arboviruses, together with continued meteorological data collection, will facilitate the assessment and prediction of future epidemics that use trends in the accelerated changes in climate. Such surveillance should go hand in hand with efforts to improve the understanding of the mechanisms driving the geographic expansion of dengue and other arboviruses beyond the current limits. https://doi.org/10.1289/EHP11616.

Horizontal transmission of Salmonella Typhimurium among German cockroaches and its possible mechanisms.

German cockroaches (Blattella germanica) can be both mechanical and biological (amplifying) vectors of enteric pathogens, including Salmonella enterica serovar Typhimurium (S. Typhimurium), which they acquire by feeding upon contaminated substances. Blattella germanica is also a gregarious species that shelters in groups and partakes in unique feeding behaviors such as conspecific coprophagy, necrophagy, and emetophagy. These properties create an interphase for potential horizontal transmission of pathogens among cockroach populations through the fecal-oral route, which could in turn enhance transmission to humans and other animals. Here, we performed a series of experiments to determine: (1) whether horizontal transmission of S. Typhimurium infection takes place in B. germanica, (2) the prevalence of the phenomenon, and (3) the route(s) through which it may occur. We reveal that true horizontal transmission of S. Typhimurium occurs among B. germanica. That is, uninfected cockroaches acquire infection of the gut when co-housed with orally infected conspecifics, albeit at low frequency. Furthermore, we provide definitive evidence that coprophagy and necrophagy are routes of transmission but could not exclude sharing of food or water as contributing routes. On the contrary, transmission by emetophagy appears less likely as oral regurgitates from infected cockroaches contained S. Typhimurium for less than one day after ingesting the bacteria. Together, our data enhance current understanding of the ecology of vector-borne S. Typhimurium transmission by cockroaches, implicating conspecific horizontal transmission as a phenomenon that contributes to maintaining infected cockroach populations independently of contact with primary sources of the pathogen. Although the relative importance of horizontal transmission of pathogens in cockroaches in the field remains to be determined, these results also highlight the important role that food and water sources in the local environment may play in cockroach-borne pathogen transmission and emphasize the importance of sanitation for not only abating infestations but also mitigating pathogen transmission.

Screening for Microplastic Uptake in an Urbanized Freshwater Ecosystem: Chondrostoma nasus (Linnaeus, 1758) Case Study

The feeding characteristics of the nase, based on its mouth morphology and feeding behavior related to aquatic habitat substrata sediments make this fish a biological uptake vector for microplastics in freshwater ecosystems. Fibers may have limited absorption through the gastrointestinal tract therefore unlikely to be found in fish gastrointestinal tissue and muscle tissue. The presence of microplastic fibers in the gastrointestinal content is proof of how difficult it is for these fibers to become embedded in other organs. The absence of microplastic fibers in muscle tissue and gastrointestinal tissue is key information for microplastic fabrication and management in aquatic ecosystems. The majority of fish have relatively low levels of microplastics; however, a few individuals have a higher dose. This is true for all types of microplastics analyzed, with the exception of fish that had just one microplastic present in the analyzed matrix. The microplastics are not concentrated in the fish muscle tissue, gastrointestinal tissue and gastrointestinal content in relation to fish age, which may be due to their different mobility in the ecosystem, or due to the recent appearance of this type of contamination and the scale at which microplastics bioaccumulate. Such a relatively common fish species must be included in the assessment and monitoring systems of the Eurasian lotic systems. The risks involved include the transfer of the freshwater environments microplastics into human tissues via the food web of fishing species with the nase as a key basis.

New records, descriptions, and redescriptions of male horse flies (Diptera: Tabanidae) in Brazil

Tabanidae Latreille are hematophagous and act as mechanical and biological vectors of several pathogens, and therefore they have been widely studied in both ecology and public health, as well as in taxonomy works. Males are nectarivorous and rarely captured, so for most species they remain unknown. Thus, we aimed to describe/redescribe the males of five species: Esenbeckia osornoi Fairchild, 1942, Acanthocera marginalis Walker, 1854, Dicladocera mutata Fairchild, 1958, Stypommisa aripuana Fairchild & Wilkerson, 1986, and Tabanus mucronatus Fairchild, 1961. Three males are described for the first time and two others are redescribed, we also provide a complete description of the species, including photographs of habitus, head and genitalia.

Biology, bionomics and life-table studies of Anopheles stephensi (Diptera: Culicidae) in Sri Lanka and estimating the vectorial potential using mathematical approximations.

Anopheles stephensi is an invasive mosquito in Sri Lanka that can potentially transmit malaria. The transmission intensity is linked with biology, bionomic and behavioral aspects of a vector that are associated with the Vectorial Capacity (VC). However, the influence of larval conditions eventually affects the vectorial potential of An. stephensi are not well understood. A colony of An. stephensi was established at the Regional Centre of the Open University of Sri Lanka, Jaffna District. The colony was maintained under confined conditions according to standard protocols. Biotypes of An. stephensi were characterized by referring to the number of egg ridges. Information on (a) biological aspects of eggs (duration for egg hatching, egg development and hatchability), (b) larval development time, larval survivorship pupation success, resting depth of larvae), (c) pupae (adult emergence rate, average time for adult emergence) and (d) adults (biting frequency, mating success gonotrophic cycle, fecundity, duration for egg-laying, percentage of sexes, adult survival/longevity) were evaluated under life-table analysis. Further, selected morphometric characters of each life cycle stage were recorded from the eggs (length and breadth), larvae (head length, width of head, length of thorax, width of thorax, length of abdomen, width of abdomen, and the total length of larvae), pupae (cephalothoracic length and width) and adults (length & width of wing, thorax and abdomen). The VC was calculated using a mathematical-based approach. Descriptive statistics, General Linear Model (GLM) and independent-sample t-test were used for the statistical analysis. All three biotypes were identified based on egg morphology. Mysorensis biotype (47%; n=470) was predominant followed by type (38.1%; n=381) and intermediate (14.9%; n=149). The mean egg length (F(2,997)=3.56; P=0.029) and breadth (F(2,997)=4.57; P=0.011) denoted significant differences among the three biotypes. The mating success of females observed was 80.7±4.45%. The mean hatching period was 1.9±0.03days, with a hatching rate of 86.2±0.77%. Overall, 8.0±0.14days were required for larval development and 30.3±0.14h were spent in the pupal stage. The pupation success was 94.5±0.37%, and the majority were males (53.1±0.73%). The mean fecundity was 106.5±6.38 eggs and a gonotrophic cycle of 3.4±0.06days. The female survival rate was 43.2±2.4%, with a mean biting frequency of 66.6±3.5%. The average VC of adult An. stephensi was estimated to be 18.7. The type biotype, which is an effective vector in the Indian subcontinent is present in Sri Lanka. According to the mathematical approximation, An. stephensi found locally has a vectorial capacity of over 18. Therefore, this study warrants the health authorities and vector control programmes to continue the entomological surveys, monitoring of vector densities and implementing appropriate vector control interventions based on biology and bionomic information of vectors.

Biogeography of the spread of bluetongue disease in sheep in Brazil

Bluetongue is caused by the Bluetongue virus (BTV), a member of the genus Orbivirus within the family of the Sedoreoviridae. The virus can spread among sheep herds, increasing economic losses mainly due to the viral transmission being carried out by a biological vector directly affected by environmental conditions. In addition to Brazil having different biomes, it is also one of the countries with the most significant environmental commitment in recent years, which may interfere with the biogeography of the disease. Thus, the present study analyzed the spatio-temporal distribution of Bluetongue (BT) in sheep and the detection of regions with a higher risk for the disease in different regions of Brazil between 2013 and 2021. During this study period, five states with official notification for BT were verified: Rio Grande do Sul (228 cases; Incidence Risk/100.000 [IR] = 5.7), Rio de Janeiro (116 cases; IR = 251.7), Amazonas (17 cases; IR = 41.12), Paraná (12 cases; IR = 2.0), and Minas Gerais (7 cases; IR = 3.7). When evaluating the annual distribution, Rio de Janeiro stood out in 2013, with an IR = 217.3, whereas Amazonas had the highest mortality rate (37.13%) in 2017. However, fatality rates of 100% were found in Rio Grande do Sul (for 53 cases) in 2017 and in Paraná (for 1 case) in 2019. The months with the highest case notifications were February and April, highlighting Rio Grande do Sul and Rio de Janeiro as the main states that contributed to these notifications. We observed the formation of two clusters of high risk of the disease: i) cluster A (Relative Risk [RRs] = 63.04 between 2013 and 2015), formed by six states comprising all states from the South and part of the Southeast and Midwest, and, ii) cluster B (RRs = 180.52, in 2017), formed only by the state of Amazonas. Based on the results, BT is not evenly distributed among Brazilian states and concentrated in the southern region, especially Rio Grande do Sul. Important control and surveillance measures must be instituted to optimize national animal health programs in Brazil.

Keystone Vector Biology Symposium 2023: emerging concepts and novel technologies

Keystone Vector Biology Symposium 2023: emerging concepts and novel technologies

FCGR2A as one novel potential target for poor survival prognosis of clear cell renal cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) is the most common type of renal cell carcinoma. Immunoglobulin FcγRIIa receptor (FCGR2A) has been implicated in various cancers, however, its role on ccRCC is not well studied. A total of 151 patients with ccRCC were recruited for the study. Cox proportional hazards regression analysis was performed to calculate the hazard radios of FCGR2A expression and tumor characteristics. Pathological changes associated with ccRCC in tumor tissue sections were analyzed by hematoxylin-eosin staining. Immunohistochemical and immunofluorescence staining were used to detect the protein expression of FCGR2A in the tissue sections. Correlation between the expression of FCGR2A and the overall survival (OS) of ccRCC patients was analyzed by biological process neural network and support vector machine. The expression of FCGR2A was significantly correlated with the TNM of tumor, family history of ccRCC and Fuhrman stage of ccRCC. Patients with high FCGR2A expression in the tumor tissue, had poorer OS than the patients with low and moderate FCGR2A expression. The Receiver operating characteristic curve showed that FCGR2A can be used as a sensitive and specific biomarker for the diagnosis of ccRCC. Western blotting revealed that the FCGR2A was expressed at higher levels in the ccRCC tissues. Biological process neural network and support vector machine fitting showed that the R2 between FCGR2A and survival time of ccRCC patients was 0.8429 and 0.7669, respectively. FCGR2A is highly expressed in ccRCC, higher expression of FCGR2A is associated with poorer OS of ccRCC.

Bio-Efficacy of Insecticides Used for Vector Control in Busia and Tororo Districts, Eastern Uganda

Reductions in malaria burden worldwide coincides with the massive scale-up of malaria treatment and prevention measures, of which vector control is the major component, particularly in SSA. The key vector control interventions in Africa including Uganda, rely heavily on utilisation of long-lasting insecticidal nets (LLINs) and insecticide-based indoor residual spraying (IRS). This study assessed the bio-efficacy of insecticides used for vector control in LLINs and IRS in Busia and Tororo. Samples of Anopheles mosquito larvae were collected from various breeding grounds before rearing them in an insectary. Emerged adults were observed under a dissecting microscope and identified using standardized morphological keys after respective bioassays on used nets and sprayed walls. Independent two sample T-test was used to test for significant differences in the mean malaria vectors diversity, mean variations, mortalities by net and wall type. Results showed that mean mortalities of Anopheles mosquitoes to used brands of nets from Busia (9.86±11.35) and Tororo (9.64 ±11.12) varied insignificantly (t=0.119, p=0.906). A disaggregated analysis for each net used revealed that, the DAWA plus 2.0 registered a highest mean mortality of mosquitos, followed by PermaNet 3.0+PBO, Olyset and PermaNet 2.0 respectively. Fludora fusion revealed highest mortalities on plastered painted wall, followed by Brick plain then mud/wattle walls at all times. The trend is similar for Actellic, but unlike Fludora fusion, Actellic exhibited mortalities lower than the 80% threshold for all the wall types and T-test (T-test P values<0.001) indicated Actellic efficacy to be significantly lower than that of Fludora fusion on all the three wall substrates. This study has shown that vector behaviour, biology and physiology need consistent monitoring and surveillance for further entomological characterisation.

Bio-Efficacy of Insecticides Used for Vector Control in Busia and Tororo Districts, Eastern Uganda

Reductions in malaria burden worldwide coincides with the massive scale-up of malaria treatment and prevention measures, of which vector control is the major component, particularly in SSA. The key vector control interventions in Africa including Uganda, rely heavily on utilisation of long-lasting insecticidal nets (LLINs) and insecticide-based indoor residual spraying (IRS). This study assessed the bio-efficacy of insecticides used for vector control in LLINs and IRS in Busia and Tororo. Samples of Anopheles mosquito larvae were collected from various breeding grounds before rearing them in an insectary. Emerged adults were observed under a dissecting microscope and identified using standardized morphological keys after respective bioassays on used nets and sprayed walls. Independent two sample T-test was used to test for significant differences in the mean malaria vectors diversity, mean variations, mortalities by net and wall type. Results showed that mean mortalities of Anopheles mosquitoes to used brands of nets from Busia (9.86±11.35) and Tororo (9.64 ±11.12) varied insignificantly (t=0.119, p=0.906). A disaggregated analysis for each net used revealed that, the DAWA plus 2.0 registered a highest mean mortality of mosquitos, followed by PermaNet 3.0+PBO, Olyset and PermaNet 2.0 respectively. Fludora fusion revealed highest mortalities on plastered painted wall, followed by Brick plain then mud/wattle walls at all times. The trend is similar for Actellic, but unlike Fludora fusion, Actellic exhibited mortalities lower than the 80% threshold for all the wall types and T-test (T-test P values<0.001) indicated Actellic efficacy to be significantly lower than that of Fludora fusion on all the three wall substrates. This study has shown that vector behaviour, biology and physiology need consistent monitoring and surveillance for further entomological characterisation.

An Updated Review of Ornithodoros Ticks as Reservoirs of African Swine Fever in Sub-Saharan Africa and Madagascar.

This updated review provides an overview of the available information on Ornithodoros ticks as reservoirs and biological vectors of the ASF virus in Africa and Indian Ocean islands in order to update the current knowledge in this field, inclusive of an overview of available methods to investigate the presence of ticks in the natural environment and in domestic pig premises. In addition, it highlights the major areas of research that require attention in order to guide future investigations and fill knowledge gaps. The available information suggests that current knowledge is clearly insufficient to develop risk-based control and prevention strategies, which should be based on a sound understanding of genotype distribution and the potential for spillover from the source population. Studies on tick biology in the natural and domestic cycle, including genetics and systematics, represent another important knowledge gap. Considering the rapidly changing dynamics affecting the African continent (demographic growth, agricultural expansion, habitat transformation), anthropogenic factors influencing tick population distribution and ASF virus (ASFV) evolution in Africa are anticipated and have been recorded in southern Africa. This dynamic context, together with the current global trends of ASFV dissemination, highlights the need to prioritize further investigation on the acarological aspects linked with ASF ecology and evolution.

Distribution of InvasiveAedesMosquitoes in West-Central Illinois, 2014–18: Record Updates forAedes japonicusandAe. albopictus

A comprehensive surveillance of Aedes mosquitoes in west-central Illinois has not been conducted in recent years, resulting in incomplete distribution records for several Illinois counties. As of 2014, out of 102 Illinois counties, active populations of Ae. japonicus had been confirmed in 15 counties, and Ae. albopictus confirmed in 34 counties. The Miller laboratory at Western Illinois University (WIU) began the WIU Vector Biology Initiative (WIU-VBI) in 2014 to address the lack of mosquito surveillance in west-central Illinois. Through this effort, the presence of Ae. japonicus was confirmed for the 1st time in Fulton, Hancock, and Schuyler counties, IL, from 2014 to 2018. Actively breeding populations were confirmed in Cass, Fulton, McDonough, and Schuyler counties, IL. Additionally, Ae. albopictus was observed for the 1st time in Cass, Fulton, Hancock, McDonough, and Schuyler counties, IL, in 2016 and 2017, with active breeding populations in Cass and McDonough counties, IL.

Shoot-root signal circuit: Phytoremediation of heavy metal contaminated soil.

High concentrations of heavy metals in the environment will cause serious harm to ecosystems and human health. It is urgent to develop effective methods to control soil heavy metal pollution. Phytoremediation has advantages and potential for soil heavy metal pollution control. However, the current hyperaccumulators have the disadvantages of poor environmental adaptability, single enrichment species and small biomass. Based on the concept of modularity, synthetic biology makes it possible to design a wide range of organisms. In this paper, a comprehensive strategy of "microbial biosensor detection - phytoremediation - heavy metal recovery" for soil heavy metal pollution control was proposed, and the required steps were modified by using synthetic biology methods. This paper summarizes the new experimental methods that promote the discovery of synthetic biological elements and the construction of circuits, and combs the methods of producing transgenic plants to facilitate the transformation of constructed synthetic biological vectors. Finally, the problems that should be paid more attention to in the remediation of soil heavy metal pollution based on synthetic biology were discussed.

Two parasitic mite species on Phlebotominae sand flies (Diptera: Psychodidae) from Türkiye: Biskratrombium persicum (Microtrombidiidae) and Eustigmaeus johnstoni (Stigmaeidae)

Sand flies (Diptera: Psychodidae) are biological vectors for Leishmania species, which are health problems for humans and animals, bacteria such as Bartonella baciliformis, and various viruses belonging to the arboviruses such as Phlebovirus, the families Flaviviridae and Reoviridae. They are also known to be in contact with entomoparasites, such as various nematodes, mites and fungi. For a faunistic study, sand flies were collected by CDC light traps set up in various localities within the scope of two separate field studies carried out in Muğla and Adana provinces, Türkiye. During this study, two ectoparasitic mite species, Eustigmaeus johnstoni Zhang and Gerson on Phlebotomus tobbi Adler, Theodor and Lourie in Muğla province and Biskratrombium persicum Majidi, Hahiqanbar and Saboori (Microtrombidiidae) on Phlebotomus alexandri (Sinton, 1928) in Adana province, were observed from Türkiye. More detailed studies are needed since there are not enough studies about parasitic mites belonging to different families that can infest sand flies, their hosts, and the damage caused by these mites.

Nanotechnology: optimal applications in anti-cancer drug medicine treatment and diagnosis

The scientific field devoted the importance of studying nanotechnology, which characterizes nanoparticles and their multi-purpose functions, especially nanomedicine techniques. The review focused on newer technologies in biomedical applications as a drug vector in cancer treatment. To occupy the center stage on most of the biological vectors of drugs for the treatment of cancer. Practically, chemical treatments have harm as they target cancerous and non-cancerous cells alike, the solubility is almost non-existent, and the inability of chemotherapy to penetrate cancerous cells, which opens the way for this technique with clear prospects for the aforementioned purpose. The ability to selectively deliver nano-drugs to targeted cancer cells in an optimal manner and to avoid non-specific interactions with healthy cells. The current review focuses on ways to improve the size, shape, and properties of nanomaterials that can be exploited in cancer therapy. The successful treatment of nanocarriers for cancer can be designed for the future as nanotherapies.

Resonant laser ionization and mass separation of 225Ac

^{225}Ac is a radio-isotope that can be linked to biological vector molecules to treat certain distributed cancers using targeted alpha therapy. However, developing ^{225}Ac-labelled radiopharmaceuticals remains a challenge due to the supply shortage of pure ^{225}Ac itself. Several techniques to obtain pure ^{225}Ac are being investigated, amongst which is the high-energy proton spallation of thorium or uranium combined with resonant laser ionization and mass separation. As a proof-of-principle, we perform off-line resonant ionization mass spectrometry on two samples of ^{225}Ac, each with a known activity, in different chemical environments. We report overall operational collection efficiencies of 10.1(2)% and 9.9(8)% for the cases in which the ^{225}Ac was deposited on a rhenium surface and a ThO_{2} mimic target matrix respectively. The bottleneck of the technique was the laser ionization efficiency, which was deduced to be 15.1(6)%.

Immunogenicity of Wild Type and Mutant Hepatitis B Surface Antigen Virus-like Particles (VLPs) in Mice with Pre-Existing Immunity against the Wild Type Vector.

Virus-like particles (VLPs), composed of the small hepatitis B virus surface antigen (HBsAgS), are the antigenic components of the hepatitis B virus (HBV) vaccine and represent the backbones for a chimeric anti-malaria vaccine and various vaccine candidates. Biological vectors have to face pre-existing anti-vector immune responses due to previous immune exposure. Vector recognition after natural infections or vaccinations can result in unwarranted outcomes, with compromising effects on clinical outcomes. In order to evaluate the impact of a pre-existing anti-HBsAgS immune response, we developed mutant VLPs composed of subunits with reduced HBsAgS-specific antigenicity. The insertion of a Plasmodium falciparum circumsporozoite protein (CSP)-derived epitope as a read-out allowed the assessment of wild type (wt) and mutant VLPs in the context of a pre-existing immune response. Mutant and wt VLP platforms with a CSP-epitope insert are immunogenic and have the ability to generate anti-CSP antibody responses in both naïve BALB/c mice and mice with a pre-existing anti-HBsAgS immune response, but with superior anti-CSP responses in mice with a pre-existing immunity. The data indicate that previous HBsAgS exposure facilitates enhanced antibody responses against foreign epitopes delivered by the HBsAgS platform, and, in this context, the state of immune sensitization alters the outcome of subsequent vaccinations.

The investigation of Culicoides (Diptera: Ceratopogonidae) species and Bluetongue virus and Schmallenberg virus in Northwest Türkiye.

Culicoides biting midges (Diptera: Ceratopogonidae) act as mechanical and biological vectors of arboviruses and are crucial in the global spread of these viruses. This study investigated the diversity of distribution of Culicoides species and the presence of Bluetongue virus (BTV) and Schmallenberg virus (SBV) in Tekirdağ province in Northwest Türkiye. The fourteen Culicoides species, such as Culicoides newsteadi, Culicoides schultzei,Culicoides nubeculosus comp., Culicoides punctatus, Culicoides circumscriptus, Culicoides obsoletus comp., Culicoides gejgelensis, Culicoides festivipennis, Culicoides longipennis, Culicoides spp., Culicoides pulicaris, Culicoides picturatus, Culicoides odiatus, Culicoides kurensis, and Culicoides flavipulicaris, were detected. Culicoides newsteadi, C. odiatus, and C. pulicaris were the most abundant species. Phylogenetic analyses of Culicoides species' ITS-1 gene region were performed. A pool of C. festivipennis was positive for SBV RNA, while the BTV genomic materials was not found in the qPCR analysis. This is the first report of the presence/detection of SBV in Culicoides species in Türkiye. The survey of bioecological and epizootiological aspects of vector species is essential in implementing effective control measures for arboviral infections.