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Revista Da Sociedade Brasileira de... 2022Malaria is a global health problem and is transmitted by the Anopheles species. Due to the epidemiological importance of the genus, studies on biological, phylogenetic,...
BACKGROUND
Malaria is a global health problem and is transmitted by the Anopheles species. Due to the epidemiological importance of the genus, studies on biological, phylogenetic, and evolutionary aspects have contributed to the understanding of adaptation, vector capacity, and resistance to insecticides. The latter may result from different causes such as mutations in the gene that encodes the sodium channel (NaV).
METHODS
In this study, the NaV subunit I scaffold of 17 anopheline species was used to infer phylogenetic relationships of the genus Anopheles using Bayesian inference. The evolutionary phylogenetic tree of the NaV gene was aligned in the AliView program and analyzed utilizing Bayesian inference, using the software MrBayes.
RESULTS
The anophelines were grouped into five well-supported clusters: 1 - Anopheles darlingi and Anopheles albimanus; 2 - Anopheles sinensis and Anopheles atroparvus; 3 - Anopheles dirus; 4 - Anopheles minimus, Anopheles culicifacies, Anopheles funestus, Anopheles maculatus, and Anopheles stephensi; and 5 - Anopheles christyi, Anopheles epiroticus, Anopheles merus, Anopheles melas, Anopheles gambiae, Anopheles coluzzii, and Anopheles arabiensis.
CONCLUSIONS
The topology confirms the phylogenetic relationships proposed in studies based on the genome of some anophelines and reflects the current taxonomy of the genus, which suggests that NaV undergoes selection pressure during the evolution of the species. These data are useful tools for inferring their ability to resist insecticides and also help in better understanding the evolutionary processes of the genus Anopheles.
Topics: Animals; Anopheles; Phylogeny; Insecticides; Bayes Theorem; Mosquito Vectors; Sodium Channels
PubMed: 36287479
DOI: 10.1590/0037-8682-0701-2021 -
ELife Oct 2022The ANOSPP amplicon panel is a genus-wide targeted sequencing panel to facilitate large-scale monitoring of species diversity. Combining information from the 62 nuclear...
The ANOSPP amplicon panel is a genus-wide targeted sequencing panel to facilitate large-scale monitoring of species diversity. Combining information from the 62 nuclear amplicons present in the ANOSPP panel allows for a more senstive and specific species assignment than single gene (e.g. COI) barcoding, which is desirable in the light of permeable species boundaries. Here, we present NNoVAE, a method using Nearest Neighbours (NN) and Variational Autoencoders (VAE), which we apply to mers resulting from the ANOSPP amplicon sequences in order to hierarchically assign species identity. The NN step assigns a sample to a species-group by comparing the -mers arising from each haplotype's amplicon sequence to a reference database. The VAE step is required to distinguish between closely related species, and also has sufficient resolution to reveal population structure within species. In tests on independent samples with over 80% amplicon coverage, NNoVAE correctly classifies to species level 98% of samples within the complex and 89% of samples outside the complex. We apply NNoVAE to over two thousand new samples from Burkina Faso and Gabon, identifying unexpected species in Gabon. NNoVAE presents an approach that may be of value to other targeted sequencing panels, and is a method that will be used to survey species diversity and transmission patterns through space and time on a large scale, with plans to analyse half a million mosquitoes in the next five years.
Topics: Animals; Anopheles; Burkina Faso; Gabon
PubMed: 36222650
DOI: 10.7554/eLife.78775 -
American Family Physician Sep 2022Each year, malaria causes an estimated 500,000 deaths worldwide. Most of these deaths occur in Africa and disproportionally affect children younger than five years...
Each year, malaria causes an estimated 500,000 deaths worldwide. Most of these deaths occur in Africa and disproportionally affect children younger than five years worldwide. Human malarial disease is caused by protozoan parasites of the genus Plasmodium. The primary means of infection is through the bite of a female Anopheles mosquito. The incidence of malaria in the United States has increased since 2011, in conjunction with the increase in worldwide travel. An estimated 2,000 cases of malaria occur annually in the United States. All travelers to malaria-endemic regions should be prescribed prophylaxis. Malaria has a broad range of clinical presentations. Travelers who have symptoms of malaria should seek medical attention as soon as possible. All febrile travelers who have recently returned from a malarious area should be evaluated for malaria. The accurate, timely, and species-specific diagnosis of malaria is essential for successful treatment. Direct microscopy of Giemsa-stained blood smears is the reference standard for laboratory diagnosis. Rapid testing for malaria has emerged as an important adjunctive diagnostic modality. Malaria treatment is determined by individual patient factors and geography. The World Health Organization recommends treating uncomplicated cases of malaria with artemisinin combination therapy, except in the first trimester of pregnancy. Severe malaria is mainly caused by Plasmodium falciparum. Children, pregnant patients, and people who are not from endemic regions are at highest risk of severe malaria. Intravenous artesunate is the treatment of choice for severe malaria.
Topics: Animals; Artemisinins; Artesunate; Child; Female; Humans; Incidence; Malaria; Travel; United States
PubMed: 36126008
DOI: No ID Found -
Malaria Journal Sep 2022Sporozoites isolated from the salivary glands of Plasmodium-infected mosquitoes are a prerequisite for several basic and pre-clinical applications. Although salivary...
BACKGROUND
Sporozoites isolated from the salivary glands of Plasmodium-infected mosquitoes are a prerequisite for several basic and pre-clinical applications. Although salivary glands are pooled to maximize sporozoite recovery, insufficient yields pose logistical and analytical hurdles; thus, predicting yields prior to isolation would be valuable. Preceding oocyst densities in the midgut is an obvious candidate. However, it is unclear whether current understanding of its relationship with sporozoite densities can be used to maximize yields, or whether it can capture the potential density-dependence in rates of sporozoite invasion of the salivary glands.
METHODS
This study presents a retrospective analysis of Anopheles stephensi mosquitoes infected with two strains of the rodent-specific Plasmodium berghei. Mean oocyst densities were estimated in the midguts earlier in the infection (11-15 days post-blood meal), with sporozoites pooled from the salivary glands later in the infection (17-29 days). Generalized linear mixed effects models were used to determine if (1) mean oocyst densities can predict sporozoite yields from pooled salivary glands, (2) whether these densities can capture differences in rates of sporozoite invasion of salivary glands, and (3), if the interaction between oocyst densities and time could be leveraged to boost overall yields.
RESULTS
The non-linear effect of mean oocyst densities confirmed the role of density-dependent constraints in limiting yields beyond certain oocyst densities. Irrespective of oocyst densities however, the continued invasion of salivary glands by the sporozoites boosted recoveries over time (17-29 days post-blood meal) for either parasite strain.
CONCLUSIONS
Sporozoite invasion of the salivary glands over time can be leveraged to maximize yields for P. berghei. In general, however, invasion of the salivary glands over time is a critical fitness determinant for all Plasmodium species (extrinsic incubation period, EIP). Thus, delaying sporozoite collection could, in principle, substantially reduce dissection effort for any parasite within the genus, with the results also alluding to the potential for changes in sporozoites densities over time to modify infectivity for the next host.
Topics: Animals; Anopheles; Plasmodium berghei; Retrospective Studies; Salivary Glands; Sporozoites
PubMed: 36100902
DOI: 10.1186/s12936-022-04270-y -
Journal of Invertebrate Pathology Oct 2022Parathelohania is a genus of microsporidia that preferentially attacks Anopheline mosquitoes. This study explored some selective aspects of the epizootiology of...
Parathelohania is a genus of microsporidia that preferentially attacks Anopheline mosquitoes. This study explored some selective aspects of the epizootiology of Parathelohania iranica (Microsporidia: Amblyosporidae) in its malaria mosquito host Anopheles superpictus s.l. (Diptera: Culicidae). For this study, Sar-rok Village, a place adjacent to the type locality of the parasite, located at the central western part of Iran was visited twice a month to collect host larvae from mid-summer to mid-autumn of 2017-2021. Patent infections were detected by the whitish discoloration of the involved segments. Superficially uninfected larvae were reared up to 26 days in the insectary to elucidate hidden infections. Molecular investigation and laboratory trials were conducted to evaluate the possibility of secondary infections in subsequent days. Morphological characters were used to determine the sex of larvae and adults. Data were entered in SPSS 23.0 and analyzed with relevant statistical tests as needed. In total, 584 P. iranica infected larvae of An. superpictus s.l. were collected in the study years at day zero (D0). Extended observations in the insectary revealed that 849 larvae (84.2 %), 22 dead pupae (2.2 %), and 137 emerged adults (13.6 %) were also infected. In the first two years of the study, the mean infection rate for D0 and D0 + D1-D26 infections was 6.25 % and 15.6 %, respectively. Exposure experiments indicated that subsequent infections in larvae (D1-D26) were not affected by a possible source in the accompanying field water. Patent (D0) infections were seasonal and had about a month delay compared to the general population of larvae. Concealed infections of larvae (D1-D26) were significantly more frequent in late mosquito season (P < 0.01). It is proposed that the gradual decrease of ambient temperature and the shortening of day length postpones the growth and development of P. iranica in the affected larvae. Both sexes of larvae were involved and none of them survived beyond a couple of days. The frequency of infections in adult males (5.8 %) were significantly more than females (4 %) (P = 0.02). The infections of larvae were more common in the late mosquito season, and the infections of adults were more frequent in the early mosquito season. This suggests the relative importance of vertical and horizontal routes of transmission in early and late mosquito seasons, respectively. However, age-specific data revealed that only 26 % of hidden infections of larvae (D1-D26) were stemmed from I to II age group. This implies that the vertical route may be less efficient than the horizontal route in the transmission of P. iranica to the mosquito host. These inferences should be verified with further field and laboratory investigations.
Topics: Animals; Anopheles; Female; Larva; Male; Microsporidia; Water
PubMed: 36055409
DOI: 10.1016/j.jip.2022.107823 -
PloS One 2022Mosquitoes transmit many pathogens responsible for human diseases, such as malaria which is caused by parasites in the genus Plasmodium. Current strategies to control...
Mosquitoes transmit many pathogens responsible for human diseases, such as malaria which is caused by parasites in the genus Plasmodium. Current strategies to control vector-transmitted diseases are increasingly undermined by mosquito and pathogen resistance, so additional methods of control are required. Paratransgenesis is a method whereby symbiotic bacteria are genetically modified to affect the mosquito's phenotype by engineering them to deliver effector molecules into the midgut to kill parasites. One paratransgenesis candidate is Asaia bogorensis, a Gram-negative bacterium colonizing the midgut, ovaries, and salivary glands of Anopheles sp. mosquitoes. Previously, engineered Asaia strains using native signals to drive the release of the antimicrobial peptide, scorpine, fused to alkaline phosphatase were successful in significantly suppressing the number of oocysts formed after a blood meal containing P. berghei. However, these strains saw high fitness costs associated with the production of the recombinant protein. Here, we report evaluation of five different partner proteins fused to scorpine that were evaluated for effects on the growth and fitness of the transgenic bacteria. Three of the new partner proteins resulted in significant levels of protein released from the Asaia bacterium while also significantly reducing the prevalence of mosquitoes infected with P. berghei. Two partners performed as well as the previously tested Asaia strain that used alkaline phosphatase in the fitness analyses, but neither exceeded it. It may be that there is a maximum level of fitness and parasite inhibition that can be achieved with scorpine being driven constitutively, and that use of a Plasmodium specific effector molecule in place of scorpine would help to mitigate the stress on the symbionts.
Topics: Acetobacteraceae; Alkaline Phosphatase; Animals; Biological Control Agents; Defensins; Malaria; Mosquito Vectors; Plasmodium; Recombinant Proteins
PubMed: 36048823
DOI: 10.1371/journal.pone.0273568 -
Morbidity and Mortality Weekly Report.... Sep 2022Malaria in humans is caused by intraerythrocytic protozoa of the genus Plasmodium. These parasites are transmitted by the bite of an infective female Anopheles species...
PROBLEM/CONDITION
Malaria in humans is caused by intraerythrocytic protozoa of the genus Plasmodium. These parasites are transmitted by the bite of an infective female Anopheles species mosquito. Most malaria infections in the United States and its territories occur among persons who have traveled to regions with ongoing malaria transmission. However, among persons who have not traveled out of the country, malaria is occasionally acquired through exposure to infected blood or tissues, congenital transmission, nosocomial exposure, or local mosquitoborne transmission. Malaria surveillance in the United States and its territories provides information on its occurrence (e.g., temporal, geographic, and demographic), guides prevention and treatment recommendations for travelers and patients, and facilitates rapid transmission control measures if locally acquired cases are identified.
PERIOD COVERED
This report summarizes confirmed malaria cases in persons with onset of illness in 2018 and trends in previous years.
DESCRIPTION OF SYSTEM
Malaria cases diagnosed by blood smear microscopy, polymerase chain reaction, or rapid diagnostic tests are reported to local and state health departments through electronic laboratory reports or by health care providers or laboratory staff members directly reporting to CDC or health departments. Case investigations are conducted by local and state health departments, and reports are transmitted to CDC through the National Malaria Surveillance System (NMSS), the National Notifiable Diseases Surveillance System (NNDSS), or direct CDC clinical consultations. CDC reference laboratories provide diagnostic assistance and conduct antimalarial drug resistance marker testing on blood specimens submitted by health care providers or local or state health departments. This report summarizes data from the integration of all cases from NMSS and NNDSS, CDC clinical consultations, and CDC reference laboratory reports.
RESULTS
CDC received reports of 1,823 confirmed malaria cases with onset of symptoms in 2018, including one cryptic case and one case acquired through a bone marrow transplant. The number of cases reported in 2018 is 15.6% fewer than in 2017. The number of cases diagnosed in the United States and its territories has been increasing since the mid-1970s; the number of cases reported in 2017 was the highest since 1972. Of the cases in 2018, a total of 1,519 (85.0%) were imported cases that originated from Africa; 1,061 (69.9%) of the cases from Africa were from West Africa, a similar proportion to what was observed in 2017. Among all cases, P. falciparum accounted for most infections (1,273 [69.8%]), followed by P. vivax (173 [9.5%]), P. ovale (95 [5.2%]), and P. malariae (48 [2.6%]). For the first time since 2008, an imported case of P. knowlesi was identified in the United States and its territories. Infections by two or more species accounted for 17 cases (<1.0%). The infecting species was not reported or was undetermined in 216 cases (11.9%). Most patients (92.6%) had symptom onset <90 days after returning to the United States or its territories from a country with malaria transmission. Of the U.S. civilian patients who reported reason for travel, 77.0% were visiting friends and relatives. Chemoprophylaxis with antimalarial medications are recommended for U.S. residents to prevent malaria while traveling in countries where it is endemic. Fewer U.S. residents with imported malaria reported taking any malaria chemoprophylaxis in 2018 (24.5%) than in 2017 (28.4%), and adherence was poor among those who took chemoprophylaxis. Among the 864 U.S. residents with malaria for whom information on chemoprophylaxis use and travel region were known, 95.0% did not adhere to or did not take a CDC-recommended chemoprophylaxis regimen. Among 683 women with malaria, 19 reported being pregnant. Of these, 11 pregnant women were U.S. residents, and one of whom reported taking chemoprophylaxis to prevent malaria but her adherence to chemoprophylaxis was not reported. Thirty-eight (2.1%) malaria cases occurred among U.S. military personnel in 2018, more than in 2017 (26 [1.2%]). Among all reported malaria cases in 2018, a total of 251 (13.8%) were classified as severe malaria illness, and seven persons died from malaria. In 2018, CDC analyzed 106 P. falciparum-positive and four P. falciparum mixed species specimens for antimalarial resistance markers (although certain loci were untestable in some specimens); identification of genetic polymorphisms associated with resistance to pyrimethamine were found in 99 (98.0%), to sulfadoxine in 49 (49.6%), to chloroquine in 50 (45.5%), and to mefloquine in two (2.0%); no specimens tested contained a marker for atovaquone or artemisinin resistance.
INTERPRETATION
The importation of malaria reflects the overall trends in global travel to and from areas where malaria is endemic, and 15.6% fewer cases were imported in 2018 compared with 2017. Of imported cases, 59.3% were among persons who had traveled from West Africa. Among U.S. civilians, visiting friends and relatives was the most common reason for travel (77.1%).
PUBLIC HEALTH ACTIONS
The best way for U.S. residents to prevent malaria is to take chemoprophylaxis medication before, during, and after travel to a country where malaria is endemic. Adherence to recommended malaria prevention strategies among U.S. travelers would reduce the number of imported cases. Reported reasons for nonadherence include prematurely stopping after leaving the area where malaria was endemic, forgetting to take the medication, and experiencing a side effect. Health care providers can make travelers aware of the risks posed by malaria and incorporate education to motivate them to be adherent to chemoprophylaxis. Malaria infections can be fatal if not diagnosed and treated promptly with antimalarial medications appropriate for the patient's age, pregnancy status, medical history, the likely country of malaria acquisition, and previous use of antimalarial chemoprophylaxis. Antimalarial use for chemoprophylaxis and treatment should be determined by the CDC guidelines, which are frequently updated. In April 2019, intravenous (IV) artesunate became the first-line medication for treatment of severe malaria in the United States and its territories. Artesunate was approved by the Food and Drug Administration (FDA) in 2020 and is commercially available (Artesunate for Injection) from major U.S. drug distributors (https://amivas.com). Stocking IV artesunate locally allows for immediate treatment of severe malaria once diagnosed and provides patients with the best chance of a complete recovery and no sequelae. With commercial IV artesunate now available, CDC will discontinue distribution of non-FDA-approved IV artesunate under an investigational new drug protocol on September 30, 2022. Detailed recommendations for preventing malaria are online at https://www.cdc.gov/malaria/travelers/drugs.html. Malaria diagnosis and treatment recommendations are also available online at https://www.cdc.gov/malaria/diagnosis_treatment. Health care providers who have sought urgent infectious disease consultation and require additional assistance on diagnosis and treatment of malaria can call the Malaria Hotline 9:00 a.m.-5:00 p.m. Eastern Time, Monday-Friday, at 770-488-7788 or 855-856-4713 or after hours for urgent inquiries at 770-488-7100. Persons submitting malaria case reports (care providers, laboratories, and state and local public health officials) should provide complete information because incomplete reporting compromises case investigations and public health efforts to prevent future infections and examine trends in malaria cases. Molecular surveillance of antimalarial drug resistance markers enables CDC to track, guide treatment, and manage drug resistance in malaria parasites both domestically and globally. A greater proportion of specimens from domestic malaria cases are needed to improve the completeness of antimalarial drug resistance analysis; therefore, CDC requests that blood specimens be submitted for any case of malaria diagnosed in the United States and its territories.
Topics: Antimalarials; Artesunate; Biomarkers; Female; Humans; Malaria; Military Personnel; Population Surveillance; Pregnancy; United States
PubMed: 36048717
DOI: 10.15585/mmwr.ss7108a1 -
Journal of Agricultural and Food... Sep 2022Infected mosquitos from the genus have become one of the world's most influential contributors to human morbidity and death. To explore new biopesticides with activity...
Infected mosquitos from the genus have become one of the world's most influential contributors to human morbidity and death. To explore new biopesticides with activity against , , a species related to the subspecies group of , was investigated. Six metabolites, aureothin, allo-aureothin, deoxyaureothin, 4',7-dihydroxy isoflavone, 2-methyl-5-(3-indolyl)oxazole, and 2-ethyl-5-(3-indolyl)oxazole were isolated, and chemical structures, were elucidated based on one- and two-dimensional NMR spectroscopy analyses and HRMS. The larvicidal activity of these compounds was evaluated. Only two isomeric compounds, aureothin and allo-aureothin, showed larvicidal activity against with LC values of 1.5 and 3.1 ppm for 24 h post-treatment, respectively, and 3.8 and 7.4 ppm for 48 h post-treatment, respectively. The crude extract of also demonstrated potent larvicidal activity with LC values of 1.46 and 1.2 ppm for 24 and 48 h post-treatment, respectively. Deoxyaureothin, a furan ring reduced form of aureothin, showed no activity against . The hybrid imported fire ants activity of aureothin was also evaluated, but it did not show any activity at the highest dose of 62.5 μg/g. Described here is the first report on a bioassay-directed investigation of the secondary metabolites of and biological evaluation of isolated compounds aureothin and its isomer and intermediates as potential microbial larvicides. and crude extracts thereof are a promising source of potential microbial biolarvicides.
Topics: Aedes; Animals; Anopheles; Culex; Humans; Insecticides; Larva; Plant Extracts; Plant Leaves; Streptomyces
PubMed: 36040208
DOI: 10.1021/acs.jafc.2c03537 -
Malaria Journal Aug 2022Plasmodium parasites that cause bird malaria occur in all continents except Antarctica and are primarily transmitted by mosquitoes in the genus Culex. Culex...
BACKGROUND
Plasmodium parasites that cause bird malaria occur in all continents except Antarctica and are primarily transmitted by mosquitoes in the genus Culex. Culex quinquefasciatus, the mosquito vector of avian malaria in Hawai'i, became established in the islands in the 1820s. While the deadly effects of malaria on endemic bird species have been documented for many decades, vector-parasite interactions in avian malaria systems are relatively understudied.
METHODS
To evaluate the gene expression response of mosquitoes exposed to a Plasmodium infection intensity known to occur naturally in Hawai'i, offspring of wild-collected Hawaiian Cx. quinquefasciatus were fed on a domestic canary infected with a fresh isolate of Plasmodium relictum GRW4 from a wild-caught Hawaiian honeycreeper. Control mosquitoes were fed on an uninfected canary. Transcriptomes of five infected and three uninfected individual mosquitoes were sequenced at each of three stages of the parasite life cycle: 24 h post feeding (hpf) during ookinete invasion; 5 days post feeding (dpf) when oocysts are developing; 10 dpf when sporozoites are released and invade the salivary glands.
RESULTS
Differential gene expression analyses showed that during ookinete invasion (24 hpf), genes related to oxidoreductase activity and galactose catabolism had lower expression levels in infected mosquitoes compared to controls. Oocyst development (5 dpf) was associated with reduced expression of a gene with a predicted innate immune function. At 10 dpf, infected mosquitoes had reduced expression levels of a serine protease inhibitor, and further studies should assess its role as a Plasmodium agonist in C. quinquefasciatus. Overall, the differential gene expression response of Hawaiian Culex exposed to a Plasmodium infection intensity known to occur naturally in Hawai'i was low, but more pronounced during ookinete invasion.
CONCLUSIONS
This is the first analysis of the transcriptional responses of vectors to malaria parasites in non-mammalian systems. Interestingly, few similarities were found between the response of Culex infected with a bird Plasmodium and those reported in Anopheles infected with human Plasmodium. The relatively small transcriptional changes observed in mosquito genes related to immune response and nutrient metabolism support conclusions of low fitness costs often documented in experimental challenges of Culex with avian Plasmodium.
Topics: Animals; Canaries; Culex; Culicidae; Hawaii; Humans; Malaria; Malaria, Avian; Oocysts; Parasites; Passeriformes; Plasmodium
PubMed: 36038897
DOI: 10.1186/s12936-022-04271-x -
Pathogens (Basel, Switzerland) Aug 2022Getah virus (GETV) is a zoonotic virus transmitted by mosquitoes, belonging to the family, genus. It was first isolated from mosquitoes in Malaysia in 1955, being... (Review)
Review
Getah virus (GETV) is a zoonotic virus transmitted by mosquitoes, belonging to the family, genus. It was first isolated from mosquitoes in Malaysia in 1955, being widespread in island countries in the South Pacific region. Since the beginning of the 21st century, GETV expanded its range and geographical distribution from low-latitude tropical regions to 60° north latitude, being isolated from 17 different species of mosquitoes belonging to five genera of Culicidae (, , , and ), as well as from midges in Eurasia. Molecular genetic evolution analysis revealed large molecular differences between the mosquitoes currently circulating Eurasia and those in the South Pacific in 1950s. The number of disease outbreaks caused by GETV in animals is increasing alongside the types of animals infected, from horses and pigs to cattle, blue foxes and red pandas. The disease burden is severely underestimated, and the economic cost to livestock production remains unknown. Herein, we review GETV temporal and spatial distribution, molecular genetic evolution, transmission and data on disease outbreaks. This work provides a reference for public health workers engaged in GETV research and zoonotic disease prevention and control.
PubMed: 36015065
DOI: 10.3390/pathogens11080945