Blood-Feeding Patterns and Resting Behavior of Aedes aegypti from Three Health Districts of Ouagadougou City, Burkina Faso.

Recent dengue outbreaks have occurred in Ouagadougou and Bobo-Dioulasso, the two major cities of Burkina Faso. Dengue is a viral disease transmitted primarily by Aedes aegypti, a highly anthropophilic mosquito that thrives in human-transformed environments and breeds predominantly in artificial containers. In 2018, we investigated the resting and blood-feeding habits of Ae. aegypti in urban settings of Ouagadougou. In a 3-month cross-sectional study starting in August 2018, indoors and outdoors resting adult mosquitoes were collected using Prokopack aspirators in three health districts (HD). All mosquitoes were morphologically identified, and DNA was extracted from blood-fed Ae. aegypti females. A multiplex polymerase chain reaction with specific primers was used to identify the origin of the blood meal. A total of 4,256 adult Ae. aegypti mosquitoes, including 1,908 females, were collected. A preference for exophily was recorded in Bogodogo and Nongremassom, although an unexpectedly higher proportion of blood-fed females were found indoors than outdoors. Respectively, 96.09%, 91.03%, and 95.54% of the blood meals successfully analyzed in Baskuy, Bogodogo, and Nongremassom were from a single human host, with the remainder from domestic mammals as single or multiple hosts. Modeling total Ae. aegypti and blood-fed female counts showed that among other predictors, human density, outdoor environment, and house type affect their total densities. Our study revealed an exophilic tendency as well as a pronounced anthropophilic preference of Ae. aegypti adults, critical findings to consider when planning accurate entomological surveillance and effective interventions against Ae. aegypti in urban settings.

Wolbachia infection in Aedes aegypti does not affect its vectorial capacity for Dirofilaria immitis.

Mosquito-borne diseases such as dengue and filariasis are a growing public health concern in endemic countries. Biological approaches, such as the trans-infection of Wolbachia pipientis in mosquitoes, are an alternative vector control strategy, especially for arthropod-borne viruses such as dengue. In the present study, the effect of Wolbachia (wMel strain) on the vectorial capacity of Aedes aegypti for Dirofilaria immitis was studied. Our results showed that Wolbachia does not affect the phenotype of mosquito survival or the prevalence, number, and molting rate of third-stage larvae in both susceptible and resistant strains of Ae. aegypti. RNA-seq analysis of Malpighian tubules at 2 days post-infection with D. immitis showed the differentially expressed genes (DEGs) with and without wMel infection. No characteristic immune-related gene expression patterns were observed among the DEGs. No significant change in the amount of Wolbachia was observed in the Ae. aegypti after D. immitis infection. Our results suggest that infection of D. immitis in Ae. aegypti populations will not interfere with Wolbachia-based vector control strategies in dengue-endemic areas where cases of D. immitis are present. This study demonstrated the veterinary medical validity of a dengue control program using Wolbachia.

Fibrinopeptide A-induced blood-feeding arrest in the yellow fever mosquito Aedes aegypti.

Female mosquitoes engage in blood feeding from their hosts to facilitate egg maturation but cease feeding once a sufficient blood meal has been acquired. Abdominal distention has been proposed as a contributing factor; however, it has also been suggested that there are chemical controls. In this study, we focus on negative chemical regulators of blood feeding, particularly those present in the host blood. Serum derived from animal blood inhibits the feeding of ATP, a phagostimulant of blood feeding in Aedes aegypti. Fibrinopeptide A (FPA), a 16-amino acid peptide cleaved from fibrinogen during blood coagulation, serves as an inhibitory factor in the serum. Our findings suggest that blood-feeding arrest in female mosquitoes is triggered by the detection of FPA in the host blood, which increases as blood coagulation proceeds in the mosquito's midgut, highlighting the role of host-derived substances as negative regulators of mosquito behavior.

First report of V1016I, F1534C and V410L kdr mutations associated with pyrethroid resistance in Aedes aegypti populations from Niamey, Niger.

BACKGROUND: Ae. aegypti is the vector of important µ arboviruses, including dengue, Zika, chikungunya and yellow fever. Despite not being specifically targeted by insecticide-based control programs in West Africa, resistance to insecticides in Ae. aegypti has been reported in countries within this region. In this study, we investigated the status and mechanisms of Ae. aegypti resistance in Niamey, the capital of Niger. This research aims to provide baseline data necessary for arbovirus outbreak prevention and preparedness in the country. METHODS: Ovitraps were used to collect Ae. aegypti eggs, which were subsequently hatched in the insectary for bioassay tests. The hatched larvae were then reared to 3-5-day-old adults for WHO tube and CDC bottle bioassays, including synergist tests. The kdr mutations F1534C, V1016I, and V410L were genotyped using allele-specific PCR and TaqMan qPCR methods. RESULTS: Ae. aegypti from Niamey exhibited moderate resistance to pyrethroids but susceptibility to organophosphates and carbamates. The kdr mutations, F1534C, V1016I and V410L were detected with the resistant tri-locus haplotype 1534C+1016L+410L associated with both permethrin and deltamethrin resistance. Whereas the homozygote tri-locus resistant genotype 1534CC+1016LL+410LL was linked only to permethrin resistance. The involvement of oxidase and esterase enzymes in resistance mechanisms was suggested by partial restoration of mosquitoes' susceptibility to pyrethroids in synergist bioassays. CONCLUSION: This study is the first report of Ae. aegypti resistance to pyrethroid insecticides in Niamey. The resistance is underpinned by target site mutations and potentially involves metabolic enzymes. The observed resistance to pyrethroids coupled with susceptibility to other insecticides, provides data to support evidence-based decision-making for Ae. aegypti control in Niger.

Key Features and Considerations for Using Automated Long-Term Monitoring of Heat-Seeking Behavior of Mosquitoes.

Mosquitoes are vectors of various deadly infectious diseases, including malaria and dengue fever. Because these pathogens are transmitted by mosquito blood-feeding behavior, it is important to understand how mosquitoes are attracted to their hosts and how they feed on blood. The simplest method is to observe their behavior with the naked eye or video recording. Furthermore, various devices have been invented to assay mosquito behavior, such as olfactometers. Although each method has distinctive advantages, all have disadvantages, such as limitations in the number of individuals that can be assayed at one time and in observable durations, objective quantification methods, and others. To solve these problems, we have developed an automated device to quantify the carbon dioxide-activated heat-seeking behavior of Anopheles stephensi and Aedes aegypti with continuous monitoring for up to 1 week. This device, which is detailed in an accompanying protocol, can be applied to search for substances and molecules that affect heat-seeking behavior. It may also be applicable to other hematophagous insects.

Automated Long-Term Monitoring of the Heat-Seeking Behavior of Mosquitoes.

Heat is one of the critical cues female mosquitoes use to find vertebrate hosts, particularly in the final step of attraction (touching down on hosts) before the initiation of blood-sucking. To prevent vector-borne diseases such as malaria and dengue fever, which are transmitted via mosquito blood-sucking, it is essential to understand the dynamics and mechanisms of the heat-seeking behavior of mosquitoes. An automated device to quantify CO2-activated heat-seeking behavior with continuous monitoring for up to a week was established. The device is based on the infrared beam break method; it can simultaneously monitor three independent mosquito behaviors (touchdown on a heated target, feeding, and locomotion activity) by using several pairs of infrared laser sensors. This protocol describes brief instructions for the device's construction, directions for use, and possible issues and solutions.

Association of 410L, 1016I and 1534C kdr mutations with pyrethroid resistance in Aedes aegypti from Ouagadougou, Burkina Faso, and development of a one-step multiplex PCR method for the simultaneous detection of 1534C and 1016I kdr mutations.

BACKGROUND: Since 2000, Burkina Faso has experienced regular dengue cases and outbreaks, making dengue an increasingly important health concern for the country. Previous studies in Burkina Faso reported that resistance of Aedes aegypti to pyrethroid insecticides was associated with the F1534C and V1016I kdr mutations. The current study reports high resistance of Ae. aegypti populations to pyrethroid insecticides, likely supported by mutations in the voltage-gated sodium channel, here evidenced by genotyping the kdr SNPs V410L, V1016I and F1534C. We also describe a new multiplex PCR-based diagnostic of F1534C and V1016I kdr SNPs. METHODS: Larvae of Ae. aegypti were collected from three health districts of Ouagadougou in 2018. The resistance status of Ae. aegypti to permethrin (15 µg/ml) and deltamethrin (10 µg/ml) was tested using bottles and to malathion (5%) using WHO tube tests. All bioassays used 1-h exposure and mortality recorded 24 h post-exposure. Bioassay results were interpreted according to WHO thresholds for resistance diagnosis. The kdr mutations were screened using AS-PCR and TaqMan methods in exposed and non-exposed Aedes mosquitoes. RESULTS: Females from all health districts were resistant to permethrin and deltamethrin (< 20% mortality) but were fully susceptible to 5% malathion. The F1534C and V1016I kdr mutations were successfully detected using a newly developed multiplex PCR in perfect agreement with TaqMan method. The 1534C/1016I/410L haplotype was correlated with permethrin resistance but not with deltamethrin resistance; however, the test power was limited by a low frequency of dead individuals in deltamethrin exposure. CONCLUSIONS: Resistance to pyrethroid insecticides is associated with kdr mutant haplotypes, while the absence of substantial resistance to malathion suggests that it remains a viable option for dengue vector control in Ouagadougou.

Surveillance of Getah virus in mosquitoes and racehorses from 2016 to 2019 at a training center in Ibaraki Prefecture, Japan, a site of several previous Getah virus outbreaks.

Mosquitoes and EDTA-treated blood samples from febrile racehorses were investigated for Getah virus infection from 2016 to 2019 at the Miho Training Center, where several outbreaks of Getah virus have occurred. We collected 5557 mosquitoes and 331 blood samples from febrile horses in this study. The most frequently captured mosquito species was Culex tritaeniorhynchus (51.9%), followed by Aedes vexans nipponii (14.2%) and Anopheles sinensis (11.2%). Getah virus was detected in mosquitoes (Aedes vexans nipponii) in 2016 (strain 16-0810-26) but not in 2017-2019. Six of 74 febrile horses in 2016 and one of 69 in 2019 tested positive for Getah virus; none of the horses tested positive in 2017 or 2018. Phylogenetic and sequence analysis showed that strain 16-0810-26 was closely related to strains that had been isolated from horses and a pig around the training center in 2014-2016 but have not been detected in samples collected at the training center since 2017. In contrast, the strain isolated from the infected horse in 2019 (19-I-703) was genetically distinct from the strains isolated from horses and a pig in 2014-2016 and was more closely related to a strain isolated in 1978 at the training center. The source of strain 19-I-703 is unclear, but the virus was not detected in other horses sampled in 2019. In summary, we found that the distribution of mosquito species present at the training center had not changed significantly since 1979, and although a small outbreak of Getah virus infection occurred among horses at the training center in 2016, limited Getah virus activity was detected in mosquitoes and horses at the training center from 2017 to 2019.

Impact of physicochemical parameters of Aedes aegypti breeding habitats on mosquito productivity and the size of emerged adult mosquitoes in Ouagadougou City, Burkina Faso.

BACKGROUND: Outbreaks of dengue fever caused by viruses transmitted by Aedes aegypti mosquitoes are repeated occurrences in West Africa. In recent years, Burkina Faso has experienced major dengue outbreaks, most notably in 2016 and 2017 when 80% of cases were recorded in Ouagadougou City (Central Health Region). In order to better understand the ecology of this vector and to provide information for use in developing control measures, a study on the characteristics of Aedes container breeding sites and the productivity of such sites, as measured by the abundance of immature stages and resultant adult body size, was undertaken in three health districts (Baskuy, Bogodogo and Nongremassom) of Ouagadougou. METHODS: Adult mosquitoes were collected indoors and outdoors in 643 households during the rainy season from August to October 2018. The presence of water containers was systematically recorded and the containers examined for the presence or absence of larvae. Characteristics of the container breeding sites, including size of the container and temperature, pH and conductivity of the water contained within, were recorded as well as the volume of water. Traditional Stegomyia indices were calculated as quantitative indicators of the risk of dengue outbreaks; generalised mixed models were fitted to larval and pupal densities, and the contribution of each covariate to the model was evaluated by the Z-value and associated P-value. RESULTS: A total of 1061 container breeding sites were inspected, of which 760 contained immature stages of Ae. aegypti ('positive' containers). The most frequent container breeding sites found in each health district were tyres and both medium (buckets/cans/pots) and large (bins/barrels/drums) containers; these containers were also the most productive larval habitats and the types that most frequently tested positive. Of the Stegomyia indices, the Breteau, House and Container indices exceeded WHO dengue risk thresholds. Generalised linear mixed models showed that larval and pupal abundances were associated with container type, physicochemical characteristics of the water and collection month, but there were significant differences among container types and among health districts. Aedes aegypti body size was positively associated with type and diameter of the container, as well as with electrical conductivity of the water, and negatively associated with pH and temperature of the water and with the level of exposure of the container to sunlight. CONCLUSION: This study provides data on putative determinants of the productivity of habitats regarding Ae. aegypti immature stages. These data are useful to better understand Ae. aegypti proliferation. The results suggest that identifying and targeting the most productive container breeding sites could contribute to dengue vector control strategies in Burkina Faso.

Effectiveness of Rapid Antigen Testing in Forensic Cases of Severe Acute Respiratory Syndrome Coronavirus 2 Infection, Including Delta Variant.

ABSTRACT: The polymerase chain reaction is indispensable for diagnosing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in forensic cases. However, studies regarding the effectiveness of rapid antigen testing (RAT) in forensic cases remain limited. Therefore, we investigated the efficacy of RAT compared with reverse-transcription quantitative polymerase chain reaction (RT-qPCR) for confirming SARS-CoV-2 infection (including the delta variant). Before the external examination or autopsy, we collected samples from the nasopharyngeal mucosa, which were then assessed via RAT (QuickNavi COVID-19 Ag kit, QuickNavi-Flu+COVID-19 Ag kit) and RT-qPCR. Reverse-transcription quantitative polymerase chain reaction results were positive in 73 of 1255 cases, and 21 cases were identified as those of delta variants. Low RT-qPCR threshold cycle value cases and delta variant infections were more likely to result in coronavirus disease-related deaths. The sensitivity of the QuickNavi COVID-19 Ag kit was 76.32%, and that of the QuickNavi-Flu+COVID-19 Ag kit was 77.14%. The specificity of both RATs was 100%. In QuickNavi COVID-19 Ag kit cases, delta variant cases showed lower sensitivity than non-delta variant cases, even for a similar viral load. Thus, RAT in forensic cases is sufficiently useful as a screening test for SARS-CoV-2 infection. However, RAT carries a risk of false negatives, especially for delta variant cases.

A human tissue-based assay identifies a novel carrion blowfly strain for maggot debridement therapy.

Maggot debridement therapy (MDT) is a form of therapeutic wound treatment in which live fly larvae are used intentionally to debride necrotic tissues. MDT has been widely used to treat chronic wounds in humans or animals, such as diabetic foot ulcers. Larvae of a carrion blowfly, Lucilia sericata (green bottle fly), debride wounds by consuming necrotic tissue and removing pathogenic bacteria, promoting effective wound healing. Most medical L. sericata strains were initially collected from natural environments using animal meat as bait and reared on artificial protein-rich media or ground meat. It remains to be examined which strain would be more appropriate for MDT, whereas any method for evaluating the fly's therapeutic potential in humans has not been available. A feeding assay was developed using minced human tissues obtained from surgical waste. To establish L. sericata strains highly eligible for MDT, carrion fly larvae were collected from 45 corpses subjected to forensic autopsy (such as decomposed bodies). Four corpse-derived L. sericata strains were obtained and evaluated using the feeding assay. One strain showed that its feeding activity was 1.4 times higher than the control strain used in conventional MDT. The body length of the adult fly of the corpse-derived strain was longer than the control, which was consistent with the observation that its cell size was enlarged. The human tissue-based assay developed in this study accurately evaluated the ability of fly larvae to debride necrotic wounds. The L. sericata strain newly established from human corpses harboring high feeding activity may offer a clinically significant improvement in MDT.

First comprehensive analysis of Aedes aegypti bionomics during an arbovirus outbreak in west Africa: Dengue in Ouagadougou, Burkina Faso, 2016-2017.

BACKGROUND: Dengue's emergence in West Africa was typified by the Burkina Faso outbreaks in 2016 and 2017, the nation's largest to date. In both years, we undertook three-month surveys of Aedes populations in or near the capital city Ouagadougou, where the outbreaks were centered. METHODOLOGY: In 1200LG (urban), Tabtenga (peri-urban) and Goundry (rural) localities, we collected indoor and outdoor resting mosquito adults, characterized larval habitats and containers producing pupae and reared immature stages to adulthood in the laboratory for identification. All mosquito adults were identified morphologically. Host species (from which bloodmeals were taken) were identified by PCR. Generalized mixed models were used to investigate relationships between adult or larval densities and multiple explanatory variables. RESULTS: From samples in 1,780 houses, adult Ae. aegypti were significantly more abundant in the two urban localities (Tabtenga and 1200 LG) in both years than in the rural site (Goundry), where Anopheles spp. were far more common. Results from adult collections indicated a highly exophilic and anthropophilic (>90% bloodmeals of human origin) vector population, but with a relatively high proportion of bloodfed females caught inside houses. Habitats producing most pupae were waste tires (37% of total pupae), animal troughs (44%) and large water barrels (30%). While Stegomyia indices were not reliable indicators of adult mosquito abundance, shared influences on adult and immature stage densities included rainfall and container water level, collection month and container type/purpose. Spatial analysis showed autocorrelation of densities, with a partial overlap in adult and immature stage hotspots. CONCLUSION: Results provide an evidence base for the selection of appropriate vector control methods to minimize the risk, frequency and magnitude of future outbreaks in Ouagadougou. An integrated strategy combining community-driven practices, waste disposal and insecticide-based interventions is proposed. The prospects for developing a regional approach to arbovirus control in West Africa or across Africa are discussed.

Clinical outcomes in pregnant women with coronavirus disease 2019 in a perinatal medical centre in Japan: a retrospective study of the first 1 year of the pandemic.

In this retrospective study, we analysed clinical and demographic data from the medical records of 31 pregnant women with coronavirus disease 2019 (COVID-19) who were treated at our hospital between April 2020 and April 2021. The most common symptom was a fever; ∼10% of patients were asymptomatic. One patient with rapidly worsening pneumonia needed a Caesarean Section at 30 weeks and was admitted for intensive care. Twelve patients received perinatal care in our hospital (10 live births, one stillbirth, and one artificial abortion). Six patients delivered vaginally; the others delivered via caesarean section. Two patients had complications, including severe hypertensive disorders and preeclampsia. All patients recovered from COVID-19. Severe acute respiratory syndrome coronavirus 2 was not detected in the placenta, umbilical cord, cord blood, amniotic fluid, vaginal fluid, or breast milk in any patient. There were no neonatal adverse outcomes. The possibility of transmitting the coronavirus to pregnancy-related samples was low.IMPACT STATEMENTWhat is already known on the subject? COVID-19 has been affecting different countries in diverse ways, and the incidence, mortality, and morbidity rates of patients with COVID-19 vary widely by country or region and race. These differences in results may reflect racial differences and differences in national health care systems. Moreover, the information about the perinatal outcomes of pregnant women with COVID-19 and their newborns from Japan is limited.What do the results of this study add to what is known? We described the perinatal outcomes of 31 Japanese pregnant women with COVID-19 who were managed safely in a perinatal medical centre in Tokyo Japan, during the first 1 year of the pandemic.What are the implications of these findings for clinical practice and/or further research? Severe pneumonia and perinatal complications may occur, although no maternal and neonatal deaths were observed for COVID-19-positive pregnant women in our facility. Therefore, it is important to prevent this infection during pregnancy with the provision of effective medical care.

Perinatal management of a pregnant woman with COVID-19: A case report from Japan.

OBJECTIVE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the coronavirus disease 2019 (COVID-19) pandemic. Owing to limited information, the impact and clinical course of COVID-19 in pregnant women and newborns remain unclear. Here, we report the clinical course of a full-term pregnant woman with COVID-19 and her newborn. CASE REPORT: A 27-year-old pregnant woman with a fever and sore throat was diagnosed with COVID-19. To prevent and control SARS-CoV-2 infection to the newborn and medical staff, delivery was performed via cesarean section. Reverse-transcription quantitative polymerase chain reaction results of the placenta, umbilical cord, cord blood, amniotic fluid, vaginal fluid, breastmilk, newborn anal wipes, and nasopharyngeal samples were negative for SARS-CoV-2. An acute increase in maternal blood pressure and HELLP syndrome-like blood data fluctuations were observed after delivery. CONCLUSION: Perinatal management of patients with COVID-19 could be safely performed for medical staff and newborns under adequate infection control measures.

Comprehensive Severe Acute Respiratory Syndrome Coronavirus 2 Detection Using Polymerase Chain Reaction and Rapid Antigen Testing in Postmortem Specimens.

ABSTRACT: Polymerase chain reaction (PCR) is indispensable for diagnosing coronavirus disease 2019 (COVID-19) in autopsy cases. In this study, we performed comprehensive reverse transcription quantitative PCR (RT-qPCR) and rapid antigen tests for COVID-19 on forensic postmortem specimens, regardless of the antemortem symptoms and causes of death. Immediately before forensic external examination and autopsy, a wiping solution was collected from the nasopharynx with a dry swab, and rapid antigen testing and RT-qPCR were performed. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was detected by RT-qPCR in 12 of the 487 cases; the infection rate was 2.46%. Of the RT-qPCR-positive cases, 7 were associated with COVID-19-related deaths. Cycle threshold values were not correlated with the cause of death or postmortem time. The sensitivity and specificity of the rapid antigen test were 91.67% and 100.00%, respectively. The RT-qPCR positivity rate of forensic cases was higher than the cumulative infection rate for the entire population. SARS-CoV-2 could be detected with the rapid antigen test and RT-qPCR within 216 hours of death. Because the rapid antigen test showed the same sensitivity and specificity as those observed in clinical practice, the test combined with RT-qPCR may be useful for diagnosing COVID-19 even in postmortem specimens.

Molecular action of larvicidal flavonoids on ecdysteroidogenic glutathione S-transferase Noppera-bo in Aedes aegypti.

BACKGROUND: Mosquito control is a crucial global issue for protecting the human community from mosquito-borne diseases. There is an urgent need for the development of selective and safe reagents for mosquito control. Flavonoids, a group of chemical substances with variable phenolic structures, such as daidzein, have been suggested as potential mosquito larvicides with less risk to the environment. However, the mode of mosquito larvicidal action of flavonoids has not been elucidated. RESULTS: Here, we report that several flavonoids, including daidzein, inhibit the activity of glutathione S-transferase Noppera-bo (Nobo), an enzyme used for the biosynthesis of the insect steroid hormone ecdysone, in the yellow fever mosquito Aedes aegypti. The crystal structure of the Nobo protein of Ae. aegypti (AeNobo) complexed with the flavonoids and its molecular dynamics simulation revealed that Glu113 forms a hydrogen bond with the flavonoid inhibitors. Consistent with this observation, substitution of Glu113 with Ala drastically reduced the inhibitory activity of the flavonoids against AeNobo. Among the identified flavonoid-type inhibitors, desmethylglycitein (4',6,7-trihydroxyisoflavone) exhibited the highest inhibitory activity in vitro. Moreover, the inhibitory activities of the flavonoids correlated with the larvicidal activity, as desmethylglycitein suppressed Ae. aegypti larval development more efficiently than daidzein. CONCLUSION: Our study demonstrates the mode of action of flavonoids on the Ae. aegypti Nobo protein at the atomic, enzymatic, and organismal levels.

Rapid Spread of Severe Fever with Thrombocytopenia Syndrome Virus by Parthenogenetic Asian Longhorned Ticks.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is spreading rapidly in Asia. This virus is transmitted by the Asian longhorned tick (Haemaphysalis longicornis), which has parthenogenetically and sexually reproducing populations. Parthenogenetic populations were found in ≥15 provinces in China and strongly correlated with the distribution of severe fever with thrombocytopenia syndrome cases. However, distribution of these cases was poorly correlated with the distribution of populations of bisexual ticks. Phylogeographic analysis suggested that the parthenogenetic population spread much faster than bisexual population because colonization is independent of sexual reproduction. A higher proportion of parthenogenetic ticks was collected from migratory birds captured at an SFTSV-endemic area, implicating the contribution to the long-range movement of these ticks in China. The SFTSV susceptibility of parthenogenetic females was similar to that of bisexual females under laboratory conditions. These results suggest that parthenogenetic Asian longhorned ticks, probably transported by migratory birds, play a major role in the rapid spread of SFTSV.

A method of sequential liquid dispensing for the multiplexed genetic diagnosis of viral infections in a microfluidic device.

In this study, we introduce polydimethylsiloxane (PDMS)-based microfluidic devices capable of sequential dispensing of samples into multiple reaction microchambers in a single operation to provide a fast and easy sample-to-answer platform for multiplexed genetic diagnosis of multiple viral infectious diseases. This approach utilizes the loop-mediated isothermal amplification (LAMP) method to amplify and detect specific nucleic acid (DNA/RNA) targets. We present a microfluidic flow control theory for sequential liquid dispensing phenomena, which provides design guidelines for device optimization. The device specifications, such as the possible dispensing number and maximal allowable flow rate, can be theoretically designed by optimizing the geometric dimensions of the microchannels and a pair of passive stop valves integrated into each microchamber together with the water contact angles of the materials used to fabricate the microfluidic devices. In addition, a passive stop valve with a vertical-type phaseguide structure was designed to improve device performance. We could simultaneously diagnose coronavirus disease 2019 (COVID-19) and other infectious diseases, such as severe acute respiratory syndrome (SARS), seasonal influenza A, and pandemic influenza A (H1N1) 2009. The colorimetric reverse transcription LAMP (RT-LAMP) assay suggests that the four viral infectious diseases can be detected within 30 min using a hue-based quantitative analysis, and the naked eye using our microfluidic devices.

Safety and tolerability of medicinal parasite ova (Trichuris suis) in healthy Japanese volunteers: A randomized, double-blind, placebo-controlled trial.

BACKGROUND: Trichuris suis ova (TSO), with the potential to modulate the human immune system, have been tested for therapeutic application in autoimmune and allergic diseases such as inflammatory bowel disease (IBD). Previous clinical studies were limited to European and American participants, whereas Asian populations have not been well documented. In this study, a clinical trial was conducted to examine the safety and tolerability of TSO administration among a healthy Japanese population. METHODS: The study was a randomized, double-blind, placebo-controlled trial held at Jikei University Hospital, Tokyo. Twelve volunteers were stratified into three groups receiving different doses of TSO (TSO 1000, 2500, and 7500) and another into the control group. These cases were limited to healthy Japanese men aged over 20 years old. Single doses of medicinal TSO or placebo were given to three participants of each group. All participants were followed up to 56 days after ingestion. During the follow-up period, clinical practitioners checked each participant at the clinic at 7, 14, 28, and 56 days post-ingestion (dpi). Clinical symptoms were evaluated using questionnaire-based self-reporting, which participants filled at every visit. Blood samples were drawn at 7, 14, 28, and 56 dpi. Fecal samples were collected at 28 and 56 dpi. RESULTS: During the study period, twelve healthy Japanese male volunteers were enrolled. All participants completed the follow-up period. No severe adverse events were observed during the study period in all groups. Three participants in the TSO 1000, 2500, and 7500 groups had mild to moderate abdominal symptoms, diarrhea, bloating, and appetite loss during the observation period. One participant in the placebo group presented with mild diarrhea. Microscopic examination identified no parasite ova in any fecal samples. Blood sample examination indicated elevated eosinophil count in several cases, especially in the groups with the higher dose of TSO. No extra-abdominal symptoms were present in all cases. CONCLUSIONS: Healthy Japanese people tolerated all doses of TSO without any severe adverse events. On the other hand, mild to moderate abdominal symptoms were observed in several participants. This study suggested that the medicinal use of TSO in Japan is relatively safe, and close follow-up is recommended for sustainable usage.