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1.
Parasit Vectors ; 14(1): 527, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34635176

RESUMO

The expansion of mosquito-borne diseases such as dengue, yellow fever, and chikungunya in the past 15 years has ignited the need for active surveillance of common and neglected mosquito-borne infectious diseases. The surveillance should be designed to detect diseases and to provide relevant field-based data for developing and implementing effective control measures to prevent outbreaks before significant public health consequences can occur. Mosquitoes are important vectors of human and animal pathogens, and knowledge on their biodiversity and distribution in the Afrotropical region is needed for the development of evidence-based vector control strategies. Following a comprehensive literature search, an inventory of the diversity and distribution of mosquitoes as well as the different mosquito-borne diseases found in Cameroon was made. A total of 290 publications/reports and the mosquito catalogue website were consulted for the review. To date, about 307 species, four subspecies and one putative new species of Culicidae, comprising 60 species and one putative new species of Anopheles, 67 species and two subspecies of Culex, 77 species and one subspecies of Aedes, 31 species and one subspecies of Eretmapodites, two Mansonia, eight Coquillettidia, and 62 species with unknown medical and veterinary importance (Toxorhynchites, Uranotaenia, Mimomyia, Malaya, Hodgesia, Ficalbia, Orthopodomyia, Aedeomyia, and Culiseta and Lutzia) have been collected in Cameroon. Multiple mosquito species implicated in the transmission of pathogens within Anopheles, Culex, Aedes, Eretmapodites, Mansonia, and Coquillettidia have been reported in Cameroon. Furthermore, the presence of 26 human and zoonotic arboviral diseases, one helminthic disease, and two protozoal diseases has been reported. Information on the bionomics, taxonomy, and distribution of mosquito species will be useful for the development of integrated vector management programmes for the surveillance and elimination of mosquito-borne diseases in Cameroon.


Assuntos
Culicidae/fisiologia , Mosquitos Vetores/fisiologia , Doenças Transmitidas por Vetores/transmissão , Aedes/parasitologia , Aedes/fisiologia , Aedes/virologia , Animais , Anopheles/parasitologia , Anopheles/fisiologia , Anopheles/virologia , Camarões , Culex/parasitologia , Culex/fisiologia , Culex/virologia , Culicidae/classificação , Culicidae/parasitologia , Culicidae/virologia , Surtos de Doenças , Humanos , Mosquitos Vetores/classificação , Doenças Transmitidas por Vetores/parasitologia , Doenças Transmitidas por Vetores/virologia
2.
Parasit Vectors ; 14(1): 427, 2021 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-34446069

RESUMO

BACKGROUND: Dirofilaria immitis and Dirofilaria repens are the main causative agents of heartworm disease and subcutaneous dirofilariasis in domestic and wild canids, respectively. Both pathogens have zoonotic potential and are transmitted by mosquitoes. The present study aimed to determine the transmission period, prevalence and diversity of Dirofilaria spp. vectors from endemic areas of Corsica (France). METHODS: A monthly point data model based on average temperature recorded by four meteorological stations during 2017 was used to calculate the Dirofilaria transmission period. From June to September 2017, female mosquitoes (n = 1802) were captured using Biogents® Sentinel 2 traps lured with carbon dioxide and BG-Lure™ or octanol. Mosquitoes were identified to species level, pooled accordingly, and screened using multiplex real-time qPCR to detect D. immitis and D. repens. RESULTS: The monthly point data model showed the possible transmission of Dirofilaria spp. from the third week in May to the last week in October in the studied area. Mosquitoes were identified as Ochlerotatus caspius (n = 1432), Aedes albopictus (n = 199), Culex pipiens sensu lato (n = 165) and Aedes vexans (n = 6) and were grouped into 109 pools (from 1 to 27 specimens, mean 11.4 ± 0.7), of which 16 scored positive for Dirofilaria spp. (i.e., n = 13; estimated infection rate [EIR] = 1.1% for D. immitis and n = 3; EIR = 0.2% for D. repens). Specifically, 6 (i.e., EIR = 3.8%) of 15 pools of Ae. albopictus were positive for D. immitis, 2 of 14 of Cx. pipiens s.l. were positive for D. immitis and D. repens, respectively, and 8 of 77 pools of Oc. caspius were positive for D. immitis (i.e., n = 6; EIR = 0.4%) and D. repens (i.e., 2; EIR = 0.1%). The highest mosquito infection rate was recorded in July (EIR = 2.5%), then in June (EIR = 1.3%) and September (EIR = 0.6%). CONCLUSIONS: The data suggest that both Dirofilaria species are endemic and occur possibly in sympatry in the studied area in Corsica, highlighting the need to implement preventive chemoprophylaxis and vector control strategies to reduce the risk of these filarioids in dog and human populations.


Assuntos
Aedes/parasitologia , Culex/parasitologia , Dirofilaria immitis/genética , Dirofilaria repens/genética , Dirofilariose/epidemiologia , Dirofilariose/transmissão , Mosquitos Vetores/parasitologia , Animais , Dirofilaria immitis/isolamento & purificação , Dirofilaria immitis/fisiologia , Dirofilaria repens/isolamento & purificação , Dirofilaria repens/fisiologia , Feminino , França/epidemiologia , Humanos , Ilhas/epidemiologia , Prevalência
3.
Parasit Vectors ; 14(1): 367, 2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34271978

RESUMO

BACKGROUND: The cryopreservation of filarial nematodes has been studied for nearly 70 years. Largely, these studies examined the effectiveness of cryopreservation methods by using the post-thaw survival of microfilariae (mf) and the development to third-stage larvae (L3s) following inoculation into a competent insect vector. Only one study reported complete reestablishment of a filarial nematode (Brugia malayi) life-cycle in a competent vertebrate host from cryopreserved stock. Expanding on this previous research, a cryopreservation method was developed to cryopreserve the mf of the dog heartworm, Dirofilaria immitis. METHODS: A combination of cryoprotectants, dimethyl sulfoxide (DMSO) and polyvinyl pyrolidone (PVP) at 6% and 4 mM, respectively, provided acceptable post-thaw survival of mf that developed into L3s in Aedes aegypti. L3s developed from cryopreserved and freshly collected mf in mosquitoes were inoculated into ferrets and dogs and were assessed after a sufficient duration post-inoculation for development into adult heartworms. RESULTS: Fewer adult heartworms derived from cryopreserved stocks of mf were recovered from ferrets compared to adult heartworms derived from freshly collected mf, and the former were smaller by weight and length. The onset of patency (circulating mf) occurred at similar post-inoculation time points and at similar mf densities in dogs infected with L3s sourced from cryopreserved stocks or freshly collected mf. Adults derived from cryopreserved mf have survived and produced viable mf for more than 3 years in dogs. Approximately 60% of inoculated L3s were recovered as adults from dogs at 2 and 3.5 years post-inoculation. CONCLUSIONS: The results from these direct comparisons demonstrate that cryopreserved mf can develop into L3s in vector mosquitoes and that these L3s are infective to both dogs and ferrets, where they undergo normal development into adult worms. These worms are able to mate and produce viable mf and complete the heartworm lifecycle in dog.


Assuntos
Aedes/parasitologia , Criopreservação/métodos , Dirofilaria immitis/fisiologia , Dirofilariose/parasitologia , Doenças do Cão/parasitologia , Furões/parasitologia , Animais , Cães , Feminino , Estágios do Ciclo de Vida , Masculino , Microfilárias , Mosquitos Vetores/parasitologia
4.
Ecology ; 102(10): e03452, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34165788

RESUMO

Parasite dilution occurs in varied systems, via multiple potential mechanisms. We used laboratory manipulation and field surveys to test for invader-induced parasite dilution via two specific mechanisms: host-host competition and encounter reduction. In the laboratory, single Aedes triseriatus larvae were exposed to one of eight combinations of: parasitic Ascogregarina barretti, +/-1 cohabiting Aedes albopictus larva during parasite exposure, and +/-1 cohabiting A. albopictus larva after infectious parasite removal. Larval infection intensity (predicted to decrease via dilution by encounter reduction) was not significantly affected by A. albopictus. Adult infection prevalence and intensity (predicted to decrease via dilution by host-host competition) were significantly greater with A. albopictus, suggesting parasite amplification by interspecific competition, an effect potentially mediated by competition increasing A. triseriatus development time. In the field, we tested for effects of potential dilution host abundances on prevalence and abundance of A. barretti in A. triseriatus larvae. Piecewise path analysis yielded no evidence of host-host competition impacting parasitism in the field, but instead indicated a significant direct negative effect of Aedes spp. abundance on parasite abundance in A. triseriatus, which is consistent with dilution via encounter reduction in the field, but only in tree holes, not in man-made containers. Our results are consistent with the hypothesis that a noncompetent invader can alter the native host-parasite relationship, but our laboratory and field data yield differing results. This difference is likely due to laboratory experiment testing for per capita effects of dilution hosts on parasitism, but field analysis testing for effects of dilution host abundance on parasitism. Individually, host-host competition with the invader amplifies, rather than dilutes, parasite success. In contrast, our path analysis is consistent with the hypothesis that dilution of parasitism results from increased abundance of noncompetent hosts in the field.


Assuntos
Aedes , Apicomplexa , Interações Hospedeiro-Parasita , Aedes/parasitologia , Animais , Espécies Introduzidas , Larva
5.
PLoS One ; 16(4): e0251100, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33930098

RESUMO

Aedes aegypti, the primary vector of various arthropod-borne viral (arboviral) diseases such as dengue and Zika, is a popular laboratory model in vector biology. However, its maintenance in laboratory conditions is difficult, mostly because the females require blood meals to complete oogenesis, which is often provided as sheep blood. The outermost layer of the mosquito cuticle is consists of lipids which protects against numerous entomopathogens, prevents desiccation and plays an essential role in signalling processes. The aim of this work was to determine how the replacement of human blood with sheep blood affects the cuticular and internal FFA profiles of mosquitoes reared in laboratory culture. The individual FFAs present in cuticular and internal extracts from mosquito were identified and quantified by GC-MS method. The normality of their distribution was checked using the Kolmogorov-Smirnov test and the Student's t-test was used to compare them. GC-MS analysis revealed similar numbers of internal and cuticular FFAs in the female mosquitoes fed sheep blood by membrane (MFSB) and naturally fed human blood (NFHB), however MFSB group demonstrated 3.1 times greater FFA concentrations in the cuticular fraction and 1.4 times the internal fraction than the NFHB group. In the MFSB group, FFA concentration was 1.6 times higher in the cuticular than the internal fraction, while for NFHB, FFA concentration was 1.3 times lower in the cuticular than the internal fraction. The concentration of C18:3 acid was 223 times higher in the internal fraction than the cuticle in the MHSB group but was absent in the NFHB group. MFSB mosquito demonstrate different FFA profiles to wild mosquitoes, which might influence their fertility and the results of vital processes studied under laboratory conditions. The membrane method of feeding mosquitoes is popular, but our research indicates significant differences in the FFA profiles of MFSB and NFHB. Such changes in FFA profile might influence female fertility, as well as other vital processes studied in laboratory conditions, such as the response to pesticides. Our work indicates that sheep blood has potential shortcomings as a substitute feed for human blood, as its use in laboratory studies may yield different results to those demonstrated by free-living mosquitoes.


Assuntos
Aedes/fisiologia , Ácidos Graxos não Esterificados/metabolismo , Fertilidade/fisiologia , Cromatografia Gasosa-Espectrometria de Massas/métodos , Mosquitos Vetores/metabolismo , Aedes/parasitologia , Animais , Feminino , Humanos , Mosquitos Vetores/parasitologia , Ovinos
6.
PLoS Negl Trop Dis ; 15(4): e0009218, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33886567

RESUMO

CONCLUSIONS/SIGNIFICANCE: The potential of RS as a surveillance tool for malaria and arbovirus vectors and MIRS for the diagnosis and surveillance of arboviruses is yet to be assessed. NIRS capacity as a surveillance tool for malaria and arbovirus vectors should be validated under field conditions, and its potential as a diagnostic tool for malaria and arboviruses needs to be evaluated. It is recommended that all 3 techniques evaluated simultaneously using multiple machine learning techniques in multiple epidemiological settings to determine the most accurate technique for each application. Prior to their field application, a standardised protocol for spectra collection and data analysis should be developed. This will harmonise their application in multiple field settings allowing easy and faster integration into existing disease control platforms. Ultimately, development of rapid and cost-effective point-of-care diagnostic tools for malaria and arboviruses based on spectroscopy techniques may help combat current and future outbreaks of these infectious diseases.


Assuntos
Infecções por Arbovirus/diagnóstico , Malária/diagnóstico , Mosquitos Vetores/parasitologia , Mosquitos Vetores/virologia , Análise Espectral , Aedes/parasitologia , Aedes/virologia , Animais , Infecções por Arbovirus/epidemiologia , Análise Custo-Benefício , Monitoramento Epidemiológico , Humanos , Malária/epidemiologia , Sistemas Automatizados de Assistência Junto ao Leito
7.
J Med Entomol ; 58(2): 983-989, 2021 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-33710313

RESUMO

Madagascar is a hotspot of biodiversity, but poverty and population growth provoke a high risk of conflict between food security and biodiversity conservation in this tropical country. Numerous vector-borne diseases, including viral infections, affect public health in Madagascar and a continuous expansion of anthropogenically used areas intensifies contact on the human-wildlife interface. However, data on human and animal pathogens in potential insect vectors is limited. Therefore, we conducted a parasitological and virological survey of 785 adult female mosquitoes between March and May 2016 at the Ankarafantsika National Park in northwestern Madagascar. Screening included Alpha-, Phlebo-, and Flaviviridae and the recently described filarial nematode species, Lemurfilaria lemuris. The predominant mosquito genus was Culex (91%), followed by Mansonia (4.1%), Anopheles (3.4%), and Aedes (0.9%). Viral screening revealed no arboviruses, but an insect-specific flavivirus in two Culex sitiens pools. No pools screened positive for the lemur-specific filarial nematode L. lemuris.


Assuntos
Flavivirus/isolamento & purificação , Mosquitos Vetores , Nematoides/isolamento & purificação , Aedes/parasitologia , Aedes/virologia , Animais , Anopheles/parasitologia , Anopheles/virologia , Biodiversidade , Culex/parasitologia , Culex/virologia , Reservatórios de Doenças , Filariose/transmissão , Lemur , Madagáscar , Mosquitos Vetores/parasitologia , Mosquitos Vetores/virologia , Viroses/transmissão
8.
J Med Entomol ; 58(4): 1958-1961, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-33677603

RESUMO

Native to the Eastern United States and Eastern Canada, Aedes triseriatus (eastern tree hole mosquito) is an important vector of La Crosse virus and dog heartworm. Although its range has been well characterized in the United States, few studies have surveyed its distribution within Canada. In this study, mosquitoes were collected from a variety of urban and rural communities throughout Manitoba, Canada between the years of 2018 and 2020. Aedes triseriatus was identified and confirmed molecularly to be present in 13 communities. This includes localities that expand the species known distribution to new northern and western areas, and suggests that past surveillance efforts have not been comprehensive or environmental factors have caused this mosquito species to be present in areas in which it was not found previously. As Canada is showing signs of a changing climate, this may be driving the broader occurrence of Ae. triseriatus.


Assuntos
Aedes , Distribuição Animal , Aedes/parasitologia , Aedes/virologia , Animais , Canadá , Mudança Climática , Dirofilariose/transmissão , Cães , Monitoramento Epidemiológico , Vírus La Crosse , Mosquitos Vetores/parasitologia , Mosquitos Vetores/virologia
9.
J Med Entomol ; 58(3): 1188-1196, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33570154

RESUMO

Although parasites are by definition costly to their host, demonstrating that a parasite is regulating its host abundance in the field can be difficult. Here we present an example of a gregarine parasite, Ascogregarina taiwanensis Lien and Levine (Apicomplexa: Lecudinidae), regulating its mosquito host, Aedes albopictus Skuse (Diptera: Culicidae), in Bermuda. We sampled larvae from container habitats over 2 yr, assessed parasite prevalence, and estimated host abundance from egg counts obtained in neighboring ovitraps. We regressed change in average egg count from 1 yr to the next on parasite prevalence and found a significant negative effect of parasite prevalence. We found no evidence of host density affecting parasite prevalence. Our results demonstrate that even for a parasite with moderate virulence, host regulation can occur in the field.


Assuntos
Aedes/fisiologia , Apicomplexa/fisiologia , Interações Hospedeiro-Parasita , Mosquitos Vetores/fisiologia , Aedes/crescimento & desenvolvimento , Aedes/parasitologia , Animais , Bermudas , Larva/crescimento & desenvolvimento , Larva/parasitologia , Larva/fisiologia , Mosquitos Vetores/crescimento & desenvolvimento , Mosquitos Vetores/parasitologia , Dinâmica Populacional
10.
Parasit Vectors ; 14(1): 30, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33413579

RESUMO

BACKGROUND: Mosquitoes transmit filarial nematodes to both human and animal hosts, with worldwide health and economic consequences. Transmission to a vertebrate host requires that ingested microfilariae develop into infective third-stage larvae capable of emerging from the mosquito proboscis onto the skin of the host during blood-feeding. Determining the number of microfilariae that successfully develop to infective third-stage larvae in the mosquito host is key to understanding parasite transmission potential and to developing new strategies to block these worms in their vector. METHODS: We developed a novel method to efficiently assess the number of infective third-stage filarial larvae that emerge from experimentally infected mosquitoes. Following infection, individual mosquitoes were placed in wells of a multi-well culture plate and warmed to 37 °C to stimulate parasite emergence. Aedes aegypti infected with Dirofilaria immitis were used to determine infection conditions and assay timing. The assay was also tested with Brugia malayi-infected Ae. aegypti. RESULTS: Approximately 30% of Ae. aegypti infected with D. immitis and 50% of those infected with B. malayi produced emerging third-stage larvae. Once D. immitis third-stage larvae emerged at 13 days post infection, the proportion of mosquitoes producing them and the number produced per mosquito remained stable until at least day 21. The prevalence and intensity of emerging third-stage B. malayi were similar on days 12-14 post infection. Increased uptake of D. immitis microfilariae increased the fitness cost to the mosquito but did not increase the number of emerging third-stage larvae. CONCLUSIONS: We provide a new assay with an associated set of infection conditions that will facilitate assessment of the filarial transmission potential of mosquito vectors and promote preparation of uniformly infectious third-stage larvae for functional assays. The ability to quantify infection outcome will facilitate analyses of molecular interactions between vectors and filariae, ultimately allowing for the establishment of novel methods to block disease transmission.


Assuntos
Aedes/parasitologia , Bioensaio/métodos , Brugia Malayi/fisiologia , Dirofilaria immitis/fisiologia , Larva/fisiologia , Mosquitos Vetores/parasitologia , Animais , Brugia Malayi/isolamento & purificação , Dirofilaria immitis/isolamento & purificação , Dirofilariose/parasitologia , Dirofilariose/transmissão , Microfilárias/fisiologia
11.
Malar J ; 20(1): 11, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33407511

RESUMO

BACKGROUND: The invasion of the mosquito salivary glands by Plasmodium sporozoites is a critical step that defines the success of malaria transmission and a detailed understanding of the molecules responsible for salivary gland invasion could be leveraged towards control of vector-borne pathogens. Antibodies directed against the mosquito salivary gland protein SGS1 have been shown to reduce Plasmodium gallinaceum sporozoite invasion of Aedes aegypti salivary glands, but the specific role of this protein in sporozoite invasion and in other stages of the Plasmodium life cycle remains unknown. METHODS: RNA interference and CRISPR/Cas9 were used to evaluate the role of A. aegypti SGS1 in the P. gallinaceum life cycle. RESULTS: Knockdown and knockout of SGS1 disrupted sporozoite invasion of the salivary gland. Interestingly, mosquitoes lacking SGS1 also displayed fewer oocysts. Proteomic analyses confirmed the abolishment of SGS1 in the salivary gland of SGS1 knockout mosquitoes and revealed that the C-terminus of the protein is absent in the salivary gland of control mosquitoes. In silico analyses indicated that SGS1 contains two potential internal cleavage sites and thus might generate three proteins. CONCLUSION: SGS1 facilitates, but is not essential for, invasion of A. aegypti salivary glands by P. gallinaceum and has a dual role as a facilitator of parasite development in the mosquito midgut. SGS1 could, therefore, be part of a strategy to decrease malaria transmission by the mosquito vector, for example in a transgenic mosquito that blocks its interaction with the parasite.


Assuntos
Aedes/genética , Proteínas de Insetos/genética , Plasmodium gallinaceum/fisiologia , Proteínas e Peptídeos Salivares/genética , Aedes/parasitologia , Sequência de Aminoácidos , Animais , Feminino , Trato Gastrointestinal/parasitologia , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Mosquitos Vetores/genética , Mosquitos Vetores/parasitologia , Glândulas Salivares/parasitologia , Proteínas e Peptídeos Salivares/química , Proteínas e Peptídeos Salivares/metabolismo , Alinhamento de Sequência , Esporozoítos/fisiologia
12.
Parasit Vectors ; 14(1): 79, 2021 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-33494790

RESUMO

BACKGROUND: Mosquitoes are vectors for diseases such as dengue, malaria and La Crosse virus that significantly impact the human population. When multiple mosquito species are present, the competition between species may alter population dynamics as well as disease spread. Two mosquito species, Aedes albopictus and Aedes triseriatus, both inhabit areas where La Crosse virus is found. Infection of Aedes albopictus by the parasite Ascogregarina taiwanensis and Aedes triseriatus by the parasite Ascogregarina barretti can decrease a mosquito's fitness, respectively. In particular, the decrease in fitness of Aedes albopictus occurs through the impact of Ascogregarina taiwanensis on female fecundity, larval development rate, and larval mortality and may impact its initial competitive advantage over Aedes triseriatus during invasion. METHODS: We examine the effects of parasitism of gregarine parasites on Aedes albopictus and triseriatus population dynamics and competition with a focus on when Aedes albopictus is new to an area. We build a compartmental model including competition between Aedes albopictus and triseriatus while under parasitism of the gregarine parasites. Using parameters based on the literature, we simulate the dynamics and analyze the equilibrium population proportion of the two species. We consider the presence of both parasites and potential dilution effects. RESULTS: We show that increased levels of parasitism in Aedes albopictus will decrease the initial competitive advantage of the species over Aedes triseriatus and increase the survivorship of Aedes triseriatus. We find Aedes albopictus is better able to invade when there is more extreme parasitism of Aedes triseriatus. Furthermore, although the transient dynamics differ, dilution of the parasite density through uptake by both species does not alter the equilibrium population sizes of either species. CONCLUSIONS: Mosquito population dynamics are affected by many factors, such as abiotic factors (e.g. temperature and humidity) and competition between mosquito species. This is especially true when multiple mosquito species are vying to live in the same area. Knowledge of how population dynamics are affected by gregarine parasites among competing species can inform future mosquito control efforts and help prevent the spread of vector-borne disease.


Assuntos
Aedes/parasitologia , Apicomplexa/isolamento & purificação , Animais , Interações Hospedeiro-Parasita , Modelos Estatísticos , Controle de Mosquitos/métodos , Mosquitos Vetores/parasitologia , Dinâmica Populacional
13.
Nat Commun ; 12(1): 269, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33431834

RESUMO

Chemical matter is needed to target the divergent biology associated with the different life cycle stages of Plasmodium. Here, we report the parallel de novo screening of the Medicines for Malaria Venture (MMV) Pandemic Response Box against Plasmodium asexual and liver stage parasites, stage IV/V gametocytes, gametes, oocysts and as endectocides. Unique chemotypes were identified with both multistage activity or stage-specific activity, including structurally diverse gametocyte-targeted compounds with potent transmission-blocking activity, such as the JmjC inhibitor ML324 and the antitubercular clinical candidate SQ109. Mechanistic investigations prove that ML324 prevents histone demethylation, resulting in aberrant gene expression and death in gametocytes. Moreover, the selection of parasites resistant to SQ109 implicates the druggable V-type H+-ATPase for the reduced sensitivity. Our data therefore provides an expansive dataset of compounds that could be redirected for antimalarial development and also point towards proteins that can be targeted in multiple parasite life cycle stages.


Assuntos
Antimaláricos/uso terapêutico , Descoberta de Drogas , Malária/tratamento farmacológico , Malária/transmissão , Pandemias , Aedes/parasitologia , Animais , Antimaláricos/química , Antimaláricos/farmacologia , Análise por Conglomerados , Relação Dose-Resposta a Droga , Células Hep G2 , Humanos , Concentração Inibidora 50 , Estágios do Ciclo de Vida/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/parasitologia , Malária/epidemiologia , Masculino , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/crescimento & desenvolvimento
14.
Acta Trop ; 213: 105735, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33159896

RESUMO

Vector-borne diseases in the United States have recently increased as a result of the changing nature of vectors, hosts, reservoirs, parasite/pathogens, and the ecological and environmental conditions. While most focus has been on mosquito-borne pathogens affecting humans, little is known regarding parasites of companion animal, livestock and wildlife and their potential mosquito hosts in the United States. This study assessed the prevalence of mature infections of Dirofilaria immitis and avian malaria parasites (Haemosporida) within urban mosquito (Diptera, Culicidae) communities in Oklahoma. 2,620 pools consisting of 12,686 mosquitoes from 13 species collected over two summers were tested for the presence of filarioid and haemosporidian DNA. Dirofilaria immitis-infected mosquitoes were detected only in Aedes albopictus (MIR=0.18-0.22) and Culex pipiens complex (MIR=0.12) collected in cities in central and southern Oklahoma. Two other filarioid nematode species with 91-92% similarity with Onchocerca spp. and Mansonella spp. were also detected. Haemosporidian DNA was detected in 13 mosquito pools (0.9% of pools tested) from seven mosquito species out of 13 species tested. Plasmodium DNA in four species (Cx. coronator, Cx. pipiens complex, Cx. tarsalis, and Psorophora columbiae) had high homology with published sequences of avian Plasmodium species while DNA in four other species (Cx. nigripalpus, Ps. columbiae, Anopheles quadrimaculatus, and An. punctipennis) were closely related to Plasmodium species from deer. One pool of Cx. tarsalis was positive with a 100% sequence identity of Haemoproteus sacharovi. This study provides a baseline concerning the diversity of parasites in different mosquito species present in the southern Great Plains. These studies provide important information for understanding the factors of transmission involving the mosquito community, potential hosts, and different mosquito-borne parasites in this important region involved in livestock management and wildlife conservation.


Assuntos
Culicidae/parasitologia , Filarioidea/isolamento & purificação , Haemosporida/isolamento & purificação , Mosquitos Vetores/parasitologia , Plasmodium/isolamento & purificação , Aedes/parasitologia , Animais , Anopheles/parasitologia , Aves , Culex/parasitologia , Cervos , Dirofilaria immitis/genética , Dirofilaria immitis/isolamento & purificação , Filarioidea/genética , Haemosporida/genética , Humanos , Malária Aviária/epidemiologia , Malária Aviária/parasitologia , Malária Aviária/transmissão , Oklahoma , Plasmodium/genética
15.
PLoS Negl Trop Dis ; 14(10): e0008763, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33095805

RESUMO

A group of four human inhabited Nancowry Islands in Nicobar district in the Andaman and Nicobar Islands, India having a population of 7674 is the lone focus of diurnally sub-periodic Wuchereria bancrofti (DspWB) that is transmitted by Aedes niveus (Ludlow). Microfilaria (Mf) prevalence was above 1% even after nine rounds of Mass Drug Administration (MDA) with DEC and albendazole. Molecular xenomonitoring (MX) was conducted to identify appropriate vector sampling method and assess the impact. BioGents Sentinel traps, gravid traps and human baited double bed nettraps were used in three locations in each village to collect Aedes niveus female mosquitoes. Subsequently daytime man landing collections (MLC) were carried out in all the 25 villages in the islands. Collections were compared in terms of the number of vector mosquitoes captured per trap collection. Females of Ae. niveus were pooled, dried and processed for detecting filarial parasite DNA using RT-PCR assay. Vector infection rate was estimated using PoolScreen software. Only 393 female mosquitoes including 44 Ae. niveus (11.2%) were collected from 459 trap collections using three trapping devices. From 151 MLCs, 2170 Ae. niveus female mosquitoes were collected. The average prevalence of W. bancrofti DNA was 0.43%. Estimated upper 95% CI exceeded the provisional prevalence threshold of 0.1% in all the villages, indicating continued transmission as observed in Mf survey. MLCs could be the choice, for now, to sample Ae. niveus mosquitoes. The PCR assay used in MX for nocturnally periodic bancroftian filariasis could be adopted for DspWB. The vector-parasite MX, can be used to evaluate interventions in this area after further standardization of the protocol.


Assuntos
Aedes/parasitologia , Filariose Linfática/transmissão , Insetos Vetores/parasitologia , Wuchereria bancrofti/fisiologia , Aedes/efeitos dos fármacos , Aedes/fisiologia , Animais , Filariose Linfática/parasitologia , Feminino , Humanos , Índia , Controle de Insetos , Insetos Vetores/efeitos dos fármacos , Insetos Vetores/fisiologia , Ilhas , Masculino , Wuchereria bancrofti/isolamento & purificação
16.
J Vis Exp ; (162)2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32865535

RESUMO

Edhazardia aedis is a microsporidian parasite of Aedes aegypti mosquitoes, a disease vector that transmits multiple arboviruses which cause millions of disease cases each year. E. aedis causes mortality and reduced reproductive fitness in the mosquito vector and has been explored for its potential as a biocontrol agent. The protocol we present for culturing E. aedis is based on its natural infection cycle, which involves both horizontal and vertical transmission at different life stages of the mosquito host. Ae. aegypti mosquitoes are exposed to spores in the larval stage. These infected larvae then mature into adults and transmit the parasite vertically to their offspring. Infected offspring are then used as a source of spores for future horizontal transmission. Culturing E. aedis can be challenging to the uninitiated given the complexities of the parasite's life cycle, and this protocol provides detailed guidance and visual aids for clarification.


Assuntos
Aedes/parasitologia , Microsporídios , Parasitologia/métodos , Animais , Transmissão de Doença Infecciosa , Transmissão Vertical de Doenças Infecciosas , Larva/parasitologia , Mosquitos Vetores
18.
PLoS Negl Trop Dis ; 14(8): e0008615, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32813707

RESUMO

The mosquito microbiome alters the physiological traits of medically important mosquitoes, which can scale to impact how mosquito populations sustain disease transmission. The mosquito microbiome varies significantly within individual mosquitoes and among populations, however the ecological and environmental factors that contribute to this variation are poorly understood. To further understand the factors that influence variation and diversity of the mosquito microbiome, we conducted a survey of the bacterial microbiome in the medically important mosquito, Aedes albopictus, on the high Pacific island of Maui, Hawai'i. We detected three bacterial Phyla and twelve bacterial families: Proteobacteria, Acitinobacteria, and Firmicutes; and Anaplasmataceae, Acetobacteraceae, Enterobacteriaceae, Burkholderiaceae, Xanthobacteraceae, Pseudomonadaceae, Streptomycetaceae, Staphylococcaceae, Xanthomonadaceae, Beijerinckiaceae, Rhizobiaceae, and Sphingomonadaceae. The Ae. albopictus bacterial microbiota varied among geographic locations, but temperature and rainfall were uncorrelated with this spatial variation. Infection status with an ampicomplexan pathosymbiont Ascogregarina taiwanensis was significantly associated with the composition of the Ae. albopictus bacteriome. The bacteriomes of mosquitoes with an A. taiwanensis infection were more likely to include several bacterial symbionts, including the most abundant lineage of Wolbachia sp. Other symbionts like Asaia sp. and several Enterobacteriaceae lineages were less prevalent in A. taiwanensis-infected mosquitoes. This highlights the possibility that inter- and intra-domain interactions may structure the Ae. albopictus microbiome.


Assuntos
Aedes/microbiologia , Aedes/parasitologia , Bactérias/classificação , Microbiota/fisiologia , Infecções Protozoárias em Animais/microbiologia , Doenças dos Animais , Animais , Apicomplexa , Bactérias/genética , Interações Hospedeiro-Parasita , Larva/microbiologia , Larva/parasitologia , Simbiose
19.
Parasit Vectors ; 13(1): 383, 2020 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-32727546

RESUMO

BACKGROUND: Dirofilaria immitis is a parasitic nematode transmitted by mosquitoes and the cause of heartworm disease in dogs and dirofilariasis in humans and other mammals. The parasite is endemic worldwide. Vector stage research requires a reliable supply of D. immitis microfilariae (mf). It is believed that cryopreserved mf would retain viability and provide a powerful tool for vector stage research. However, reports on cryopreservation of D. immitis mf are limited. Therefore, this study aimed to validate commercial cryopreservation media to establish a practical, convenient and reproducible storage procedure for D. immitis mf. METHODS: Six different commercially available cryopreservation media were compared with the traditional polyvinylpyrrolidone-dimethyl sulfoxide (PVP-DMSO) preservation solution. In vitro viability of purified D. immitis mf and mf-infected total blood was analyzed using a motility assay and propidium iodide staining. In vivo infectivity of Aedes aegypti mosquitoes with cryopreserved mf was assessed using a mosquito survival test and quantifying the number of third-stage larvae (L3) after 13 days post-infection. RESULTS: Purified mf cryopreserved in CultureSure showed the best viability when compared to mf cryopreserved in the remaining five commercially available media and PVP-DMSO. Viability of mf in mf-infected total blood cryopreserved in CultureSure varied with the ratio of infected blood to CultureSure. Optimum results were obtained with 200 µl mf-infected blood:800 µl CultureSure. CultureSure was also the optimum medium for cryopreserving mf prior to infectivity of A. aegypti. The number of L3 was approximately the same for CultureSure cryopreserved mf (3× concentrated solution) and non-cryopreserved fresh mf. CONCLUSIONS: CultureSure is an optimal commercial cryopreservation solution for the storage of D. immitis purified mf, mf-infected total blood, and mf used for in vivo mosquito experiments. Furthermore, this study describes an easy preservation method for clinical D. immitis-infected blood samples facilitating vector stage studies, as well as the study of macrocyclic lactone resistance in heartworms and the education of veterinarians.


Assuntos
Criopreservação/métodos , Dirofilaria immitis/crescimento & desenvolvimento , Microfilárias/crescimento & desenvolvimento , Aedes/parasitologia , Animais , Dirofilariose , Doenças do Cão/parasitologia , Cães , Mosquitos Vetores/parasitologia
20.
Med Vet Entomol ; 34(4): 432-439, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32671880

RESUMO

This study aimed to evaluate the effects of egg dormancy times on susceptibility of larvae of the floodwater mosquito Aedes albifasciatus (Diptera: Culicidae) to parasitism by their natural enemy Strelkovimermis spiculatus (Nematoda: Mermithidae) and on their life history traits. Aedes albifasciatus eggs stored for 2, 4, 6, 8 and 10 months were hatched, and the larvae either exposed to S. spiculatus (treatment group) or not exposed (control group). Egg dormancy time had a negative effect on the retention of parasites, but no effect on the prevalence and intensity of parasitism or the melanization of nematodes. The survival to adulthood of control individuals decreased as dormancy time increased, whereas that of exposed individuals that remained uninfected was constant and low. A trend towards increasing development times with longer dormancy times was detected in the control group, but not in the exposed noninfected group. The results suggest nonconsumptive effects of parasites in exposed but not infected larvae from eggs with short dormancy times. In contrast, the relatively low fitness of larvae from eggs with long dormancy times regardless of their contact with the nematodes may be the result of the nutritional deprivation during the egg stage.


Assuntos
Aedes , Mermithoidea , Aedes/parasitologia , Animais , Interações Hospedeiro-Parasita , Mermithoidea/patogenicidade , Infecções por Nematoides/parasitologia , Óvulo/parasitologia , Prevalência
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