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1.
BMC Infect Dis ; 21(1): 265, 2021 Mar 17.
Article in English | MEDLINE | ID: mdl-33731022

ABSTRACT

BACKGROUND: Increasing arbovirus infections have been a global burden in recent decades. Many countries have experienced the periodic emergence of arbovirus diseases. However, information on the prevalence of arboviruses is largely unknown or infrequently updated because of the lack of surveillance studies, especially in Africa. METHODS: A surveillance study was conducted in Gabon, Central Africa, on arboviruses, which are a major public health concern in Africa, including: West Nile virus (WNV), dengue virus (DENV), Zika virus (ZIKV), yellow fever virus (YFV), chikungunya virus (CHIKV), and Rift Valley fever virus (RVFV). Serological and molecular assays were performed to investigate past infection history and the current status of infection, using serum samples collected from healthy individuals and febrile patients, respectively. RESULTS: The overall seroprevalence during 2014-2017 was estimated to be 25.3% for WNV, 20.4% for DENV, 40.3% for ZIKV, 60.7% for YFV, 61.2% for CHIKV, and 14.3% for RVFV. No significant differences were found in the seroprevalence of any of the viruses between the male and female populations. However, a focus on the mean age in each arbovirus-seropositive individual showed a significantly younger age in WNV- and DENV-seropositive individuals than in CHIKV-seropositive individuals, indicating that WNV and DENV caused a relatively recent epidemic in the region, whereas CHIKV had actively circulated before. Of note, this indication was supported by the detection of both WNV and DENV genomes in serum samples collected from febrile patients after 2016. CONCLUSIONS: This study revealed the recent re-emergence of WNV and DENV in Gabon as well as the latest seroprevalence state of the major arboviruses, which indicated the different potential risks of virus infections and virus-specific circulation patterns. This information will be helpful for public health organizations and will enable a rapid response towards these arbovirus infections, thereby preventing future spread in the country.


Subject(s)
Arboviruses/isolation & purification , Dengue/epidemiology , Zika Virus Infection/epidemiology , Adolescent , Animals , Arbovirus Infections/diagnosis , Arbovirus Infections/epidemiology , Arboviruses/classification , Child , Child, Preschool , Communicable Diseases, Emerging , Dengue/diagnosis , Female , Fever/epidemiology , Fever/virology , Gabon/epidemiology , Humans , Infant , Male , Public Health , Seroepidemiologic Studies , Zika Virus Infection/diagnosis
2.
AJR Am J Roentgenol ; : 1-8, 2021 Mar 11.
Article in English | MEDLINE | ID: mdl-33703928

ABSTRACT

OBJECTIVE. Yellow fever is a hemorrhagic disease caused by an arbovirus endemic in South America; outbreaks have occurred in recent years. The purpose of this study was to describe abdominal ultrasound findings in patients with severe yellow fever and correlate them with clinical and laboratory data. MATERIALS AND METHODS. A retrospective cohort study was performed between January and April 2018. The subjects were patients admitted to an ICU with polymerase chain reaction-confirmed yellow fever. Bedside sonography was performed within 48 hours of admission. Images were independently analyzed by two board-certified radiologists. Laboratory test samples were collected within 12 hours of image acquisition. Multivariable logistic regression analysis was performed to identify 30-day mortality predictors; p < .05 was considered statistically significant. RESULTS. Forty-six patients (40 [87%] men, six [13%] women; mean age, 47.5 ± 15.2 years) were evaluated with bedside sonography. Laboratory tests showed high serum levels of aspartate aminotransferase (5319 U/L), total bilirubin (6.2 mg/dL), and creati-nine (4.3 mg/dL). Twenty-six (56.5%) patients died within 30 days of admission (median time to death, 5 days [interquartile range, 2-9 days]). The most frequent ultrasound findings were gallbladder wall thickening (80.4%), increased renal cortex echogenicity (71.7%), increased liver parenchyma echogenicity (65.2%), perirenal fluid (52.2%), and ascites (30.4%). Increased renal echogenicity was associated with 30-day mortality (84.6% versus 55.0%; p = .046) and was an independent predictor of this outcome after multivariate analysis (odds ratio, 10.89; p = .048). CONCLUSION. Reproducible abdominal ultrasound findings in patients with severe yellow fever may be associated with severity of disease and prognosis among patients treated in the ICU.

3.
Mol Biol Rep ; 48(1): 41-55, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33454908

ABSTRACT

Mosquito-transmitted diseases like zika, dengue, chikungunya, and yellow fever are known to affect human health worldwide. Numerous synthetic insecticides have been used as vector control for these diseases, but there is the challenge of environmental toxicity and vector resistance. This study investigated the medicinal and insecticidal potential of Lentinus squarrosulus against Aedes aegypti. The fruiting bodies were identified morphologically as well as using internal transcribed spacer (ITS) sequences for its molecular characterization. Genomic deoxyribonucleic acid (DNA) yield was confirmed with NanoDrop Spectrophotometer ND-1000 and amplified with ITSl and ITS4 primers. The amplicons were sequenced and the National Center for Biotechnology Information (NCBI) database identified the nucleotides. Its ethanol extract was subjected to phytochemical screening and gas chromatography mass spectrometry (GC-MS) analysis and tested against the pupa and fourth instar larva of Aedes aegypti with percentage mortality monitored. The Macrofungus was identified morphologically and confirmed with molecular characterization as Lentinus squarrosulus (LS). The gene sequence was deposited in GenBank (Accession number MK629662.1). GC-MS analysis showed that its ethanol extract has 25 bioactive compounds with 9,12-Octadecadienoic acid, ethyl ester having the highest percentage of 43.32% as well as methyl-2-oxo-1-pyrrolidine acetate and 17-octadecynoic acid having the lowest percentage (0.09%). The macrofungus contained varied concentrations of phytochemicals including phenols (159 mg/g GAE), tannins (1.6 mg/g TAE), and flavonoids (31.4 mg/g QE). The ethanol extract had significant potent effects on Aedes aegypti larva and pupa which could be due to the occurrence and abundance of 9,12-octadecadienoic acid in LS. The LC50 of the extract for larvicidal and pupicidal activities were 2.95 mg/mL and 3.55 mg/mL, respectively, while its LC90 were 6.31 mg/mL and 5.75 mg/mL respectively. Lentinus squarrosulus had insecticidal effects against the Aedes aegypti larva and pupa and possessed great potential as a source of alternative medicine and eco-friendly insecticides.

4.
Article in English | MEDLINE | ID: mdl-33353025

ABSTRACT

BACKGROUND: Dengue, a febrile illness, is caused by a Flavivirus transmitted by Aedes aegypti and Aedes albopictus mosquitoes. Climate influences the ecology of the vectors. We aimed to identify the influence of climatic variability on the occurrence of clinical dengue requiring hospitalization in Zone-5, a high incidence area of Dhaka City Corporation (DCC), Bangladesh. METHODS AND FINDINGS: We retrospectively identified clinical dengue cases hospitalized from Zone-5 of DCC between 2005 and 2009. We extracted records of the four major catchment hospitals of the study area. The Bangladesh Meteorological Department (BMD) provided data on temperature, rainfall, and humidity of DCC for the study period. We used autoregressive integrated moving average (ARIMA) models for the number of monthly dengue hospitalizations. We also modeled all the climatic variables using Poisson regression. During our study period, dengue occurred throughout the year in Zone-5 of DCC. The median number of hospitalized dengue cases was 9 per month. Dengue incidence increased sharply from June, and reached its peak in August. One additional rainy day per month increased dengue cases in the succeeding month by 6% (RR = 1.06, 95% CI: 1.04-1.09). CONCLUSIONS: Dengue is transmitted throughout the year in Zone-5 of DCC, with seasonal variation in incidence. The number of rainy days per month is significantly associated with dengue incidence in the subsequent month. Our study suggests the initiation of campaigns in DCC for controlling dengue and other Aedes mosquito borne diseases, including Chikunguniya from the month of May each year. BMD rainfall data may be used to determine campaign timing.


Subject(s)
Aedes , Dengue , Rain , Animals , Bangladesh/epidemiology , Cities , Dengue/epidemiology , Dengue/transmission , Hospitals , Mosquito Vectors , Retrospective Studies , Seasons
5.
Viruses ; 12(11)2020 11 12.
Article in English | MEDLINE | ID: mdl-33198381

ABSTRACT

Yellow fever virus (YFV) is a mosquito-borne member of the genus flavivirus, including other important human-pathogenic viruses, such as dengue, Japanese encephalitis, and Zika. Herein, we report identifying 129 YFV Class II epitopes in donors vaccinated with the live attenuated YFV vaccine (YFV-17D). A total of 1156 peptides predicted to bind 17 different common HLA-DRB1 allelic variants were tested using IFNγ ELISPOT assays in vitro re-stimulated peripheral blood mononuclear cells from twenty-six vaccinees. Overall, we detected responses against 215 YFV epitopes. We found that the capsid and envelope proteins, as well as the non-structural (NS) proteins NS3 and NS5, were the most targeted proteins by CD4+ T cells from YF-VAX vaccinated donors. In addition, we designed and validated by flow cytometry a CD4+ mega pool (MP) composed of structural and non-structural epitopes in an independent cohort of vaccinated donors. Overall, this study provides a comprehensive prediction and validation of YFV epitopes in a cohort of YF-17D vaccinated individuals. With the design of a CD4 epitope MP, we further provide a useful tool to detect ex vivo responses of YFV-specific CD4 T cells in small sample volumes.

6.
Mem Inst Oswaldo Cruz ; 115: e190501, 2020.
Article in English | MEDLINE | ID: mdl-33174908

ABSTRACT

BACKGROUND: Non-human primates contribute to the spread of the yellow fever virus (YFV) and the establishment of transmission cycles in endemic areas. OBJECTIVE: To describe the severe histopathological aspects of YFV infection, 10 squirrel monkeys were infected with YFV and blood, brain, liver, kidney, spleen, heart, lung, lymph node and stomach were collected at 1-7, 10, 20 and 30 days post-infection (dpi). METHODS: Histopathological analysis and detection of the genome and viral antigens and neutralising antibodies were performed by RT-PCR, immunohistochemistry and neutralisation test, respectively. FINDINGS: Only one animal died from the experimental infection. The genome and viral antigens were detected in all investigated organs (1-30 dpi) and the neutralising antibodies from seven to 30 dpi. The brain contained perivascular haemorrhage (6 dpi); in the liver, midzonal haemorrhage and lytic necrosis (6 dpi) were observed. The kidney had bleeding in the Bowman's capsule and tubular necrosis (6 dpi). Pyknotic lymphocytes were observed in the spleen (1-20 dpi), the lung had haemorrhage (2-6 dpi), in the endocardium it contained nuclear pyknosis and necrosis (2-3 dpi) and the stomach contained blood in the lumen (6 dpi). MAIN FINDINGS: Squirrel monkeys reliably reproduced the responses observed in human cases of yellow fever and, therefore, constitute an excellent experimental model for studies on the pathophysiology of the disease.

7.
PLoS Negl Trop Dis ; 14(10): e0008691, 2020 10.
Article in English | MEDLINE | ID: mdl-33001982

ABSTRACT

Optimise control strategies of infectious diseases, identify factors that favour the circulation of pathogens, and propose risk maps are crucial challenges for global health. Ecological niche modelling, once relying on an adequate framework and environmental descriptors can be a helpful tool for such purposes. Despite the existence of a vaccine, yellow fever (YF) is still a public health issue. Brazil faced massive sylvatic YF outbreaks from the end of 2016 up to mid-2018, but cases in human and non-human primates have been recorded until the beginning of 2020. Here we used both human and monkey confirmed YF cases from two epidemic periods (2016/2017 and 2017/2018) to describe the spatial distribution of the cases and explore how biotic and abiotic factors drive their occurrence. The distribution of YF cases largely overlaps for humans and monkeys, and a contraction of the spatial extent associated with a southward displacement is observed during the second period of the epidemics. More contributive variables to the spatiotemporal heterogeneity of cases were related to biotic factors (mammal richness), abiotic factors (temperature and precipitation), and some human-related variables (population density, human footprint, and human vaccination coverage). Both projections of the most favourable conditions showed similar trends with a contraction of the more at-risk areas. Once extrapolated at a large scale, the Amazon basin remains at lower risk, although surrounding forest regions and notably the North-West region, would face a higher risk. Spatial projections of infectious diseases often relied on climatic variables only; here for both models, we instead highlighted the importance of considering local biotic conditions, hosts vulnerability, social and epidemiological factors to run the spatial risk analysis correctly: all YF cases occurring later on, in 2019 and 2020, were observed in the predicted at-risk areas.

8.
Rev Bras Ter Intensiva ; 32(3): 474-478, 2020.
Article in Portuguese, English | MEDLINE | ID: mdl-33053039

ABSTRACT

This case report a severe case of yellow fever complicated by liver failure and disseminated intravascular coagulation. Thromboelastometry was capable of identifying clotting disorders and guiding hemostatic therapy. We report the case of a 23-year-old male admitted to the Intensive Care Unit with sudden onset of fever, generalized muscle pain associated with liver failure, and disseminated intravascular coagulation. The results of conventional laboratory tests showed thrombocytopenia, whereas thromboelastometry suggested coagulopathy with slight hypofibrinogenemia, clotting factor consumption, and, consequently, an increased risk of bleeding. Unlike conventional laboratory tests, thromboelastometry identified the specific coagulation disorder and thereby guided hemostatic therapy. Both fibrinogen concentrates and vitamin K were administered, and no blood component transfusion was required, even in the presence of thrombocytopenia. Administration of hemostatic drugs, including fibrinogen concentrate and vitamin K, improved thromboelastometric parameters, correcting the complex coagulation disorder. Blood component transfusion was not performed, and there was no bleeding.

9.
PLoS Negl Trop Dis ; 14(9): e0008657, 2020 09.
Article in English | MEDLINE | ID: mdl-32997656

ABSTRACT

Aedes albopictus, along with Ae. aegypti, are key arbovirus vectors that have been expanding their geographic range over the last decades. In 2017, Ae. albopictus was detected for the first time at two distinct locations in Portugal. In order to understand how the Ae. albopictus populations recently introduced in Portugal are genetically related and which is their likely route of invasion, we performed an integrative cytochrome C oxidase I gene (COI)- and mitogenome-based phylogeographic analysis of mosquitoes samples collected in Portugal in 2017 and 2018 in the context of the global Ae. albopictus diversity. COI-based analysis (31 partial sequences obtained from 83 mosquitoes) revealed five haplotypes (1 to 5), with haplotype 1 (which is widely distributed in temperate areas worldwide) being detected in both locations. Haplotypes 2 and 3 were exclusively found in Southern region (Algarve), while haplotype 4 and 5 were only detected in the North of Portugal (Penafiel, Oporto region). Subsequent high discriminatory analyses based on Ae. albopictus mitogenome (17 novel sequences) not only confirmed a high degree of genetic variability within and between populations at both geographic locations (compatible with the Ae. albopictus mosquito populations circulating in Europe), but also revealed two mitogenome mutational signatures not previously reported at worldwide level. While our results generally sustain the occurrence of multiple introduction events, fine mitogenome sequence inspection further indicates a possible Ae. albopictus migration within the country, from the Northern introduction locality to the Southern region. In summary, the observed scenario of high Ae. albopictus genetic diversity in Portugal, together with the detection of mosquitoes in successive years since 2017 in Algarve and Penafiel, points that both Ae. albopictus populations seem to be already locally established, as its presence has been reported for three consecutive years, raising the public health awareness for future mosquito-borne diseases outbreaks.


Subject(s)
Aedes/genetics , Genetic Variation , Genome, Mitochondrial/genetics , Mosquito Vectors/genetics , Aedes/classification , Aedes/virology , Animals , Arboviruses , Electron Transport Complex IV/genetics , Female , Haplotypes , High-Throughput Nucleotide Sequencing , Mosquito Vectors/virology , Phylogeography , Portugal , Sequence Analysis, DNA
10.
J Virol Methods ; 286: 113976, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32971183

ABSTRACT

Zika and Dengue viruses present considerable immunological cross-reactivity, resulting in a troublesome serodiagnosis due to occurrence of false positive results. Due to Brazil's wide variety of circulating flaviviruses we aimed to access the use of in house serological tests adapted by National Reference Laboratory for Arboviruses in Brazil and evaluate commercial tests available. We evaluated in house IgM ELISAs for the individual detection of anti-ZIKV, -DENV, and -YFV IgM, against a panel of samples positive for dengue, zika, yellow fever, Rocio, Ilheus, Saint Louis encephalitis, West Nile and chikungunya. We also evaluated two commercial kits for dengue and zika IgM detection recommended by the Brazilian Ministry of Health in 2015. The sensitivity and specificity for the in house ZIKV IgM ELISA was 60.0 % and 88.6 % and for the in house DENV IgM ELISA was 100 % and 82.2 %, respectively. The in house YFV IgM ELISA presented 100 % for both sensitivity and specificity. The Novagnost Zika Virus IgM test presented a sensitivity of 47.3 % and specificity of 85.3 % and the Serion ELISA classic Dengue Virus IgM, 92.8 % and 58.9 %, respectively. Overall, both in house ELISAs for ZIKV and DENV adapted and evaluated here, presented better performances than the commercial kits tested.

11.
Rev Prat ; 70(3): 336-340, 2020 Mar.
Article in French | MEDLINE | ID: mdl-32877073

ABSTRACT

Chikungunya. Chikungunya is a cosmopolitan arbovirosis transmitted by a mosquito of the genus Aedes. It is characterized by the possible persistence of musculoskeletal symptoms more than three months after infection. After inoculation by an infected mosquito and incubation for three days, the infection is symptomatic in 75-95% of cases. There are three stages. The acute stage is characterized by the sudden onset of high fever associated with incapacitating distal polyarthralgia. Atypical, sometimes severe, manifestations are possible: neurological, digestive, cardiac, hepatic, dermatological, hematological, pulmonary and renal. These atypical forms are most often observed at extreme ages and in people with chronic diseases. The post-acute stage (60-80% of cases, from the fourth week to the end of the third month) is characterized by persistent and polymorphic musculoskeletal manifestations. During the chronic stage (50% of cases from the fourth month onwards) two entities can be distinguished: chronic inflammatory rheumatism and musculoskeletal disorders. Management is symptomatic. It is based on a precise semiological analysis, attentive listening to the patient and a multidisciplinary approach.


Subject(s)
Aedes , Arthritis, Rheumatoid , Chikungunya Fever , Chikungunya virus , Animals , Chikungunya Fever/complications , Chikungunya Fever/diagnosis , Chikungunya Fever/transmission , Chronic Disease , Humans
12.
Vet Parasitol Reg Stud Reports ; 21: 100447, 2020 07.
Article in English | MEDLINE | ID: mdl-32862888

ABSTRACT

There is limited available information concerning the prevalence of Toxoplasma gondii in noncaptive monkeys. Also, New World monkeys (NWM) are highly susceptible to toxoplasmosis, which is a conservation concern. This study aimed to investigate apicomplexan parasites in common marmosets (Callithrix jacchus) collected for yellow fever and rabies surveillance program in Northeastern region of Brazil. Heart fragments of 39 free-ranging common marmosets were analyzed for the presence of the 18S rDNA gene of apicomplexan parasites by nested PCR. Positive samples were sequenced. T. gondii DNA was detected in 17.9% (7/39) of the analyzed animals. This study is the first report on T. gondii in Callithrix jacchus in Brazil. These findings should be an alert for wildlife conservation institutions, as high susceptibility and mortality were reported for captive NWM.

13.
Rev. bras. ter. intensiva ; 32(3): 474-478, jul.-set. 2020. graf
Article in Portuguese | LILACS-Express | LILACS | ID: biblio-1138507

ABSTRACT

RESUMO Este relato de caso detalha um caso grave de febre amarela complicada por insuficiência hepática e coagulação intravascular disseminada. A tromboelastometria foi capaz de identificar os distúrbios da coagulação e orientar o tratamento hemostático. Relatamos o caso de um homem com 23 anos de idade admitido na unidade de terapia intensiva com quadro com início abrupto de febre e dor muscular generalizada associados a insuficiência hepática e coagulação intravascular disseminada. Os resultados dos exames laboratoriais convencionais revelaram trombocitopenia, enquanto a tromboelastometria sugeriu coagulopatia com discreta hipofibrinogenemia, consumo de fatores de coagulação e, consequentemente, aumento do risco de sangramento. Diferentemente dos exames laboratoriais convencionais, a tromboelastometria identificou o distúrbio de coagulação específico e, assim, orientou o tratamento hemostático. Administraram-se concentrados de fibrinogênio e vitamina K, não sendo necessária a transfusão de qualquer componente do sangue, mesmo na presença de trombocitopenia. A tromboelastometria permitiu a identificação precoce da coagulopatia e ajudou a orientar a terapêutica hemostática. A administração de fármacos hemostáticos, incluindo concentrados de fibrinogênio e vitamina K, melhorou os parâmetros tromboelastométricos, com correção do transtorno da coagulação. Não se realizou transfusão de hemocomponentes, e não ocorreu qualquer sangramento.


Abstract This case report a severe case of yellow fever complicated by liver failure and disseminated intravascular coagulation. Thromboelastometry was capable of identifying clotting disorders and guiding hemostatic therapy. We report the case of a 23-year-old male admitted to the Intensive Care Unit with sudden onset of fever, generalized muscle pain associated with liver failure, and disseminated intravascular coagulation. The results of conventional laboratory tests showed thrombocytopenia, whereas thromboelastometry suggested coagulopathy with slight hypofibrinogenemia, clotting factor consumption, and, consequently, an increased risk of bleeding. Unlike conventional laboratory tests, thromboelastometry identified the specific coagulation disorder and thereby guided hemostatic therapy. Both fibrinogen concentrates and vitamin K were administered, and no blood component transfusion was required, even in the presence of thrombocytopenia. Administration of hemostatic drugs, including fibrinogen concentrate and vitamin K, improved thromboelastometric parameters, correcting the complex coagulation disorder. Blood component transfusion was not performed, and there was no bleeding.

14.
J Biomol Struct Dyn ; : 1-13, 2020 Aug 20.
Article in English | MEDLINE | ID: mdl-32815781

ABSTRACT

Arboviruses are a group of viruses (e.g. Dengue, Chikungunya and Yellow fever virus) that are transmitted by arthropod vectors, which Aedes aegipty is the vector of main viruses in Americas. This vector is responsible to 2.4 millions of arboviruses cases in Brazil with less than a thousand deaths annually. Despite of epidemiological data, arboviruses treatment is symptomatic and the vaccine control is not effective, which makes the vector control against A. aegipty a promising strategy to diseases control. One way to achieve this goal is to development of A. aegipty sensitive olfactory modulators. Odorant binding protein 1 from A. aegypti (AaegOBP1) is essential in sensory communication, and is the first filter in odorant selection, which makes this target promising to development of new repellents. For this reason, hierarchical virtual screening (ligand-based pharmacophore model and molecular docking) together volatility filter was applied at Sigma-Aldrich database (n = 126.851) to prioritize potential molecules to repellency assays. Three compounds showed adequate stereo-electronic requirements (QFIT> 81.53), score to AaegOBP1 binding site (Score > 36.0) and volatile properties and it was chosen for repellency assays. ZINC00170981 and ZINC00131924 showed a dose-response behavior, while ZINC01621824 did not showed activity in repellency assays. Finally, Molecular Dynamics (MD) was employed to hypothesize the stability of protein-ligand complexes. According to RMSD, RMSF and binding free energy data, ZINC00170981 and ZINC00131924 were able to stabilize AaegOBP1 binding-site during the trajectory by interactions with key residues such as His77, Leu89 and Trp114). Communicated by Ramaswamy H. Sarma.

15.
PLoS Negl Trop Dis ; 14(8): e0008605, 2020 08.
Article in English | MEDLINE | ID: mdl-32797109

ABSTRACT

In human communities inhabiting areas-such as West Bengal- India-where perpetuate the pre-imago & adult developmental stages of mosquitoes; many infectious diseases are still diagnosed such as Dengue, Malaria and Acute Encephalitis Syndrome. The control of the aquatic developmental stages is one of the easiest way to prevent the emergence of adults-the blood feeding adult females being thus prevented to sample their blood meal and to lay their eggs in the aquatic milieu where develop the aquatic pre-imaginal developmental stages. Moreover, reducing the adult population size also the probability of for the blood feeding adult female mosquitoes to act as hosts and vectors of the arboviruses such as dengue virus & Japanese encephalitis virus as well as of Plasmodium. Several environmental factors including water quality parameters are responsible for the selection of oviposition sites by the female mosquitoes. In our study, larval densities of three important mosquitoes (Aedes/A. albopictus, Anopheles/An. stephensi and Culex/C. vishnui) were measured and water qualities of their habitat i.e. pH, Specific Conductance, Dissolved Oxygen, Chemical Oxygen Demand, Total alkalinity (Talk), Hardness, Nitrate nitrogen and Ammonia nitrogen were analyzed in 2017 and 2018 in many districts of West Bengal where humans beings are suffering from arboviruses and /or malaria. Whereas we have found positive correlation of density of C. vishnui and A. albopictus with the water factors except Chemical Oxygen Demand (COD) and Talk, for An. stephensi all these factors except pH, COD and Talk have positive correlation. Hardness of the water shows positive correlation with the density of An. stephensi and C. vishnui but negative correlation with density of A. albopictus. Contour plot analysis demonstrates that occurrence of each mosquito species lies in between specific range of water factors. Inter- correlation analysis revealed that mosquitoes were negatively correlated with each other. A positive correlation of the water quality parameters and larval density, over two successive years, was also noticed. In conclusion, the increasing level of pollution due to industrial and other irresponsible waste management system which changes the water quality parameters may also influence mosquito population.


Subject(s)
Ecosystem , Mosquito Control , Mosquito Vectors/physiology , Aedes/physiology , Animals , Anopheles/physiology , Arboviruses , Culex/physiology , Dengue/transmission , Encephalitis Virus, Japanese , Encephalitis, Japanese/transmission , Female , Humans , Hydrogen-Ion Concentration , India , Larva , Logistic Models , Malaria/transmission , Mosquito Vectors/parasitology , Mosquito Vectors/virology , Multivariate Analysis , Population Density , Water
16.
J Travel Med ; 27(6)2020 Sep 26.
Article in English | MEDLINE | ID: mdl-32830852

ABSTRACT

BACKGROUND: Yellow fever (YF) is a rare viral disease that can be prevented through receipt of a live attenuated vaccine. In the US military, service members must receive the YF vaccine before assignment to endemic areas, putting active duty service women at heightened risk for inadvertent exposure during preconception or pregnancy. Few studies have investigated the safety of YF vaccination in pregnancy to date, and none in a military population. METHODS: Department of Defense Birth and Infant Health Research program data were used to identify pregnancies and infants among active duty US military women, 2003-2014. Multivariable regression models estimated associations with YF vaccine exposure during preconception/pregnancy and adverse outcomes (e.g. spontaneous abortion, birth defects). Sensitivity analyses were performed that excluded pregnancies exposed to other live vaccines. For analyses of birth defects only, a secondary sensitivity analysis was performed that excluded infants diagnosed with chromosomal anomalies. RESULTS: Of the 196 802 pregnancies and 160 706 singleton infants identified, 1347 (0.7%) and 1132 (0.7%), respectively, were exposed to the YF vaccine. No increased risks for adverse pregnancy or infant outcomes were observed in the main analysis. In sensitivity analyses that excluded pregnancies exposed to other live vaccines, preconception YF vaccine exposure was associated with birth defects [adjusted risk ratio (aRR) = 1.71, 95% confidence interval (CI) = 1.08-2.73]; this association was attenuated when further excluding infants with chromosomal anomalies (aRR = 1.59, 95% CI = 0.97-2.62). CONCLUSIONS: Overall, YF vaccine exposure did not appear to be associated with most adverse outcomes among this population of pregnant military women. A tenuous association between preconception YF vaccine exposure and birth defects was observed in sensitivity analyses, which may warrant further investigation.

17.
PLoS One ; 15(7): e0229314, 2020.
Article in English | MEDLINE | ID: mdl-32706777

ABSTRACT

INTRODUCTION: Many arboviruses of public health significance are maintained in zoonotic cycles with complex transmission pathways. The presence of serum antibody against arboviruses in vertebrates provides evidence of their historical exposure but reveals nothing about the vector-reservoir relationship. Moreover, collecting blood or tissue samples from vertebrate hosts is ethically and logistically challenging. We developed a novel approach for screening the immune status of vertebrates against Ross River virus that allows us to implicate the vectors that form the transmission pathways for this commonly notified Australian arboviral disease. METHODS: A micro-plaque reduction neutralisation test (micro-PRNT) was developed and validated on koala (Phascolarctos cinereus) sera against a standard PRNT. The ability of the micro-PRNT to detect RRV antibodies in mosquito blood meals was then tested using two mosquito models. Laboratory-reared Aedes aegypti were fed, via a membrane, on sheep blood supplemented with RRV seropositive and seronegative human sera. Aedes notoscriptus were fed on RRV seropositive and seronegative human volunteers. Blood-fed mosquitoes were harvested at various time points after feeding and their blood meals analysed for the presence of RRV neutralising antibodies using the micro-PRNT. RESULTS: There was significant agreement of the plaque neutralisation resulting from the micro-PRNT and standard PRNT techniques (R2 = 0.65; P<0.0001) when applied to RRV antibody detection in koala sera. Sensitivity and specificity of the micro-PRNT assay were 88.2% and 96%, respectively, in comparison with the standard PRNT. Blood meals from mosquitoes fed on sheep blood supplemented with RRV antibodies, and on blood from RRV seropositive humans neutralised the virus by ≥50% until 48 hr post feeding. The vertebrate origin of the blood meal was also ascertained for the same samples, in parallel, using established molecular techniques. CONCLUSIONS: The small volumes of blood present in mosquito abdomens can be used to identify RRV antibodies and therefore host exposure to arbovirus infection. In tandem with the accurate identification of the mosquito, and diagnostics for the host origin of the blood meal, this technique has tremendous potential for exploring RRV transmission pathways. It can be adapted for similar studies on other mosquito borne zoonoses.


Subject(s)
Aedes/metabolism , Animal Feed/analysis , Antibodies, Viral/analysis , Neutralization Tests/methods , Ross River virus/immunology , Aedes/virology , Alphavirus Infections/diagnosis , Alphavirus Infections/transmission , Alphavirus Infections/veterinary , Animal Feed/virology , Animals , Antibodies, Viral/blood , Disease Vectors , Female , Humans , Phascolarctidae/virology , Sensitivity and Specificity
18.
PLoS Negl Trop Dis ; 14(7): e0008490, 2020 07.
Article in English | MEDLINE | ID: mdl-32716942

ABSTRACT

Owing to the increased reports in Aedes-borne diseases in the Caribbean and Latin America, the United States Agency for International Development assisted the Jamaican Ministry of Health and Wellness in conducting insecticide susceptibility tests on Aedes aegypti populations. Sentinel sites were established in seven parishes of Jamaica (St. Catherine, Kingston and St. Andrew, St. Thomas, Portland, St. Mary and St. Ann) and Aedes aegypti eggs were collected, reared to adults per collected population and their susceptibility to varying pyrethroids and organophosphates were tested using the World Health Organization paper bioassays for these insecticides. The Centers for Disease Control and Prevention bottle bioassay was used to assess susceptibility to the carbamate, bendiocarb. The voltage gated sodium channel gene mutations V1016I and I1011V, normally associated with pyrethroid resistance, were also analysed. The results showed that Aedes aegypti collected from all parishes exhibited resistance to pyrethroids at the following concentrations, permethrin 0.25-2.5%; deltamethrin 0.03-0.15%; lambda-cyhalothrin 0.03-0.3%; and etofenprox 0.5-2.5%. The insecticide deltamethrin at concentration 0.3% was the only pyrethroid tested that resulted in high mortality, 94.9 ± 0.34% knockdown within 1 hour of exposure and 98.95 ± 0.01% mortality (p <0.01) at 24 hours post exposure. The frequency of the voltage gated sodium channel gene mutation V1016I was high in the tested population, possibly accounting for the reduced sensitivity to pyrethroids. Organophosphate resistance was also observed in all populations tested. Mortality rates for 0.8% Malathion was 0.8 ± 0.70-60.68 ± 0.38% after 24 hour and 0.00-47.10 ± 3.02%, for pirimiphos-methyl 0.21%. Bendiocarb applied as 12.5 µg/ bottle resulted in mortality rates of 76.25 ± 4.30-100 ± 0.00% after 30 minutes of exposure. The results showed that Ae. aegypti from the seven parishes analysed demonstrated resistance to the insecticides tested. Deltamethrin and bendiocarb at concentrations 0.3% and 12.5µg respectively, were considered most effective, causing high mortality in the local populations. Routine monitoring and evaluations of Ae. aegypti populations from the included parishes are recommended. Additionally, the study results represent the most comprehensive testing to date with local Aedes aegypti populations distributed across different parishes of Jamaica and should be useful to guide national and sub national strategies for vector control and surveillance.


Subject(s)
Aedes/drug effects , Insecticide Resistance , Insecticides/pharmacology , Animals , Female , Jamaica
19.
Mol Immunol ; 125: 43-50, 2020 09.
Article in English | MEDLINE | ID: mdl-32645549

ABSTRACT

The CD8 T cell response to the HLA-A2-restricted epitope LLWNGPMAV (LLW) of the non-structural protein 4b of Yellow Fever Virus (YFV) is remarkably immunodominant, highly prevalent and powerful in YFV-vaccinated humans. Here we used a combinatorial peptide library screening in the context of an A2/LLW-specific CD8 T cell clone to identify a superagonist that features a methionine to isoleucine substitution at position 7. Based on in silico modeling, the functional enhancement of this LLW-7I mutation was associated with alterations in the structural dynamics of the peptide in the major histocompatibility complex (pMHC) binding with the T cell receptor (TCR). While the TCR off-rate of LLW-7I pMHC is comparable to the wild type peptide, the rigidity of the 7I peptide seems to confer less entropy loss upon TCR binding. This LLW-7I superagonist is an example of improved functionality in human CD8 T cells associated with optimized ligand rigidity for TCR binding and not with changes in TCR:pMHC off-rate kinetics.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , Immunodominant Epitopes/immunology , Receptors, Antigen, T-Cell/immunology , Viral Nonstructural Proteins/immunology , Yellow fever virus/immunology , Epitopes, T-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/immunology , HLA-A2 Antigen/chemistry , HLA-A2 Antigen/immunology , Humans , Immunodominant Epitopes/chemistry , Models, Molecular , Mutation , Peptide Library , Protein Binding/immunology , Receptors, Antigen, T-Cell/chemistry
20.
J Proteomics ; 227: 103918, 2020 Sep 15.
Article in English | MEDLINE | ID: mdl-32712372

ABSTRACT

Bacterial insecticidal proteins, such as the Bin toxin from Lysinibacillus sphaericus, could be used more extensively to control insecticide resistant mosquitoes. This study was aimed at identification of mosquito cell proteins binding Bin toxin. Results showed that purified toxin was toxic to Anopheles gambiae larvae and Ag55 cultured cells. Clathrin heavy chain (an endocytosis protein) and glycolytic enzymes such as pyruvate kinase, enolase and dihydrolipoamide dehydrogenase were identified as binders of Bin toxin. The viability of Ag55 cells in the presence of endocytosis inhibitor, pitstop2, was significantly decreased upon Bin treatment, while the inhibitor chlorpromazine did not affect Bin toxicity. Bin toxin treatment decreased ATP production and mitochondrial respiration in Ag55 cells, whereas non-mitochondrial oxygen consumption significantly increased after Bin toxin treatment. These findings are steps towards understanding how Bin toxin kills mosquitoes. SIGNIFICANCE: Mosquitoes are vectors of pathogens causing human diseases such as dengue fever, yellow fever, zika virus and malaria. An insecticidal toxin from Lysinibacillus sphaericus called Binary, or Bin, toxin could be used more extensively to control insecticide resistant mosquitoes. Bin toxin enter cells in susceptible mosquitoes and induces apoptosis or autophagy. In the current research, we used the malaria mosquito Anopheles gambiae Ag55 cell line as a model. A proteomic-based approach identified proteins that interact with Bin toxin. Interacting proteins include clathrin heavy chain (endocytosis protein) and glycolysis enzymes such as pyruvate kinase, enolase and dihydrolipoamide dehydrogenase. In Ag55 cell toxicity assays, an endocytosis inhibitor, pitstop2, increased Bin toxicity. Real time assays with a Seahorse™ flux analyzer showed that Bin significantly affects mitochondrial respiration, a result consistent with cell death via apoptosis or autophagy. These research findings add insights into how an unusual binary protein exploits cellular machinery to kill mosquitoes.

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