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1.
Int J Mol Sci ; 24(2)2023 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-36675290

RESUMO

Rice dwarf virus (RDV) is transmitted by insect vectors Nephotettix virescens and Nephotettix cincticeps (Hemiptera: Cicadellidae) that threatens rice yield and results in substantial economic losses. RDV induces two volatiles ((E)-ß-caryophyllene (EBC) and 2-heptanol) to emit from RDV-infected rice plants. However, the effects of the two volatiles on the olfactory behavior of both non-viruliferous and viruliferous N. virescens are unknown, and whether the two volatiles could facilitate the spread and dispersal of RDV remains elusive. Combining the methods of insect behavior, chemical ecology, and molecular biology, we found that EBC and 2-heptanol influenced the olfactory behavior of non-viruliferous and viruliferous N. virescens, independently. EBC attracted non-viruliferous N. virescens towards RDV-infected rice plants, promoting virus acquisition by non-viruliferous vectors. The effect was confirmed by using oscas1 mutant rice plants (repressed EBC synthesis), but EBC had no effects on viruliferous N. virescens. 2-heptanol did not attract or repel non-viruliferous N. virescens. However, spraying experiments showed that 2-heptanol repelled viruliferous N. virescens to prefer RDV-free rice plants, which would be conducive to the transmission of the virus. These novel results reveal that rice plant volatiles modify the behavior of N. virescens vectors to promote RDV acquisition and transmission. They will provide new insights into virus-vector-plant interactions, and promote the development of new prevention and control strategies for disease management.


Assuntos
Hemípteros , Oryza , Vírus de Plantas , Reoviridae , Animais , Heptanol , Insetos Vetores , Doenças das Plantas
2.
Parasit Vectors ; 16(1): 10, 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36627717

RESUMO

Mosquito vectors of eastern equine encephalitis virus (EEEV) and West Nile virus (WNV) in the USA reside within broad multi-species assemblages that vary in spatial and temporal composition, relative abundances and vector competence. These variations impact the risk of pathogen transmission and the operational management of these species by local public health vector control districts. However, most models of mosquito vector dynamics focus on single species and do not account for co-occurrence probabilities between mosquito species pairs across environmental gradients. In this investigation, we use for the first time conditional Markov Random Fields (CRF) to evaluate spatial co-occurrence patterns between host-seeking mosquito vectors of EEEV and WNV around sampling sites in Manatee County, Florida. Specifically, we aimed to: (i) quantify correlations between mosquito vector species and other mosquito species; (ii) quantify correlations between mosquito vectors and landscape and climate variables; and (iii) investigate whether the strength of correlations between species pairs are conditional on landscape or climate variables. We hypothesized that either mosquito species pairs co-occur in patterns driven by the landscape and/or climate variables, or these vector species pairs are unconditionally dependent on each other regardless of the environmental variables. Our results indicated that landscape and bioclimatic covariates did not substantially improve the overall model performance and that the log abundances of the majority of WNV and EEEV vector species were positively dependent on other vector and non-vector mosquito species, unconditionally. Only five individual mosquito vectors were weakly dependent on environmental variables with one exception, Culiseta melanura, the primary vector for EEEV, which showed a strong correlation with woody wetland, precipitation seasonality and average temperature of driest quarter. Our analyses showed that majority of the studied mosquito species' abundance and distribution are insignificantly better predicted by the biotic correlations than by environmental variables. Additionally, these mosquito vector species may be habitat generalists, as indicated by the unconditional correlation matrices between species pairs, which could have confounded our analysis, but also indicated that the approach could be operationalized to leverage species co-occurrences as indicators of vector abundances in unsampled areas, or under scenarios where environmental variables are not informative.


Assuntos
Culex , Culicidae , Vírus da Encefalite Equina do Leste , Encefalomielite Equina do Leste , Encefalomielite Equina , Febre do Nilo Ocidental , Vírus do Nilo Ocidental , Animais , Cavalos , Mosquitos Vetores , Insetos Vetores , Encefalomielite Equina/epidemiologia
3.
Trop Anim Health Prod ; 55(1): 39, 2023 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-36640201

RESUMO

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


Assuntos
Arbovírus , Vírus Bluetongue , Bluetongue , Ceratopogonidae , Doenças dos Ovinos , Animais , Ovinos , Filogenia , Insetos Vetores , Bluetongue/epidemiologia
4.
Insect Biochem Mol Biol ; 152: 103894, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36535580

RESUMO

The c-Jun N-terminal kinase (JNK) signaling pathway plays a critical role in viral infection in host cells. In addition to triggering immune reactions against pathogens, the JNK signaling pathway has also been found to benefit viral infection. Our previous work showed that JNK activation facilitated rice stripe virus (RSV) accumulation in the insect vector small brown planthopper, but the underlying mechanisms remain elusive. Here, we revealed a link between JNK activation and the transcriptional upregulation of the plasma membrane protein flotillin 2, which mediates RSV cell entry. c-Jun, a downstream substrate of JNKs, was identified as a transcription factor that targets the promoter of flotillin 2 at three binding sites. Phosphorylated c-Jun, especially at the serine 63 site, promoted the transcriptional activity of c-Jun on flotillin 2. JNK activation or inhibition affected c-Jun phosphorylation status and flotillin 2 expression. In the midguts of planthoppers, RSV infection significantly increased flotillin 2 expression and the phosphorylation level of JNKs and c-Jun. Manipulation of JNK status impacted viral acquisition in midgut cells. These findings reveal a new regulatory mechanism of the JNK signaling pathway and shed light on the virus-supportive effect of this pathway.


Assuntos
Proteínas de Membrana , Fatores de Transcrição , Animais , Proteínas de Membrana/genética , Regulação da Expressão Gênica , Fosforilação , Insetos Vetores
5.
Virus Res ; 324: 199019, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36496034

RESUMO

Rice stripe virus (RSV) causes enormous losses in rice production and is transmitted by the small brown planthopper, Laodelphax striatellus, in a persistent-propagative manner. RSV accumulation within the gut lumen of the vector is indispensable for the successful transmission to rice and insects. In this study, we obtained a 1464 bp full-length cDNA of a voltage-dependent anion channel 2 from L. striatellus (LsVDAC2), which encodes a 283 amino acid protein. RSV infection increased the expression of LsVDAC2 in the midguts and ovaries of L. striatellus by 260% and 228%, respectively. Silencing of LsVDAC2 resulted in a 88% reduction of RSV loads at 24 h after RNAi, indicating that LsVDAC2 facilitates RSV accumulation in the vector. Yeast two-hybrid and GST pulldown assays demonstrated that LsVDAC2 interacted with RSV RNA-dependent RNA polymerase, RdRp. Furthermore, experiments in vivo and in vitro showed that LsVDAC2 induced the apoptotic response in RSV-infected insects and tissues. Silencing of LsVDAC2 via RNAi significantly reduced the expression of genes for apoptosis-related caspases 1a and 1c by 62% and 78%, respectively, in RSV-infected vectors. Whether LsVDAC2-induced RSV accumulation is related to RSV RdRp and LsVDAC2-induced cell apoptosis deserves further investigation.


Assuntos
Hemípteros , Oryza , Tenuivirus , Animais , Tenuivirus/genética , Canal de Ânion 2 Dependente de Voltagem/metabolismo , Insetos Vetores , Insetos
6.
Parasit Vectors ; 15(1): 479, 2022 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-36539892

RESUMO

BACKGROUND: Existing control tools have significantly reduced malaria over the past two decades. However, progress has been stalled due to increased resistance in primary vectors and the increasing role of secondary vectors. This study aimed to investigate the impact of seasonal change on primary and secondary vector abundance and host preference. Understanding the impact of seasonal dynamics of primary and secondary vectors on disease transmission will inform effective strategies for vector management and control. METHODS: Vector abundance was measured through longitudinal collection of mosquitoes, conducted monthly during the wet and dry seasons, in Sagamaganga, a village in the Kilombero Valley, Tanzania. Mosquitoes were collected indoors using CDC light traps and backpack aspirators, and outdoors using resting buckets baited with cattle urine. In addition, a direct measure of host preference was taken monthly using human- and cattle-baited mosquito electrocuting traps. A host census was conducted to provide an indirect measure of host preference together with monthly blood meal source analysis. All collected mosquitoes were assayed for Plasmodium sporozoites. RESULTS: A total of 2828 anophelines were collected, of which 78.5% and 21.4%, were primary and secondary vectors, respectively. The abundance of the primary vectors, Anopheles arabiensis and Anopheles funestus, and of the secondary vectors varied seasonally. Indirect measures of host preference indicated that all vectors varied blood meal choice seasonally, with the direct measure confirming this for An. arabiensis. All anopheline mosquitoes tested negative for sporozoites. CONCLUSIONS: At the study location, the abundance of both primary and secondary vectors changed seasonally. Indirect and direct measures of host preference demonstrated that An. arabiensis varied from being zoophilic to being more opportunistic during the wet and dry seasons. A similar trend was observed for the other vectors.


Assuntos
Anopheles , Malária , Humanos , Animais , Bovinos , Estações do Ano , Tanzânia , Insetos Vetores , Mosquitos Vetores , Esporozoítos , Controle de Mosquitos
8.
PLoS Pathog ; 18(12): e1010996, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36520713

RESUMO

Yersinia pestis, the bacterial agent of plague, is enzootic in many parts of the world within wild rodent populations and is transmitted by different flea vectors. The ecology of plague is complex, with rodent hosts exhibiting varying susceptibilities to overt disease and their fleas exhibiting varying levels of vector competence. A long-standing question in plague ecology concerns the conditions that lead to occasional epizootics among susceptible rodents. Many factors are involved, but a major one is the transmission efficiency of the flea vector. In this study, using Oropsylla montana (a ground squirrel flea that is a major plague vector in the western United States), we comparatively quantified the efficiency of the two basic modes of flea-borne transmission. Transmission efficiency by the early-phase mechanism was strongly affected by the host blood source. Subsequent biofilm-dependent transmission by blocked fleas was less influenced by host blood and was more efficient. Mathematical modeling predicted that early-phase transmission could drive an epizootic only among highly susceptible rodents with certain blood characteristics, but that transmission by blocked O. montana could do so in more resistant hosts irrespective of their blood characteristics. The models further suggested that for most wild rodents, exposure to sublethal doses of Y. pestis transmitted during the early phase may restrain rapid epizootic spread by increasing the number of immune, resistant individuals in the population.


Assuntos
Peste , Sifonápteros , Yersinia pestis , Animais , Insetos Vetores/microbiologia , Sifonápteros/microbiologia , Roedores
9.
Artigo em Inglês | MEDLINE | ID: mdl-36542015

RESUMO

BACKGROUND: The American cutaneous leishmaniasis (ACL) is expanding in peri-urban environments. METHODS: An entomological survey was conducted in the area of the occurrence of an autochthonous urban case of ACL. Sandflies and a parasitological slide of the human case were submitted for molecular diagnosis. RESULTS: Nyssomyia whitmani and Ny. antunesi were the most frequently collected species. Ny. whitmani and Bichromomyia flaviscutellata were positive for Leishmania guyanensis and L. lainsoni, respectively. The human case tested positive for L. lainsoni. CONCLUSIONS: Sandflies and Leishmania parasites present in urban forest may occur frequently in nearby domiciliary environments; thus, these areas must be monitored.


Assuntos
Leishmania guyanensis , Leishmania , Leishmaniose Cutânea , Psychodidae , Animais , Humanos , Urbanização , Insetos Vetores/parasitologia , Leishmaniose Cutânea/epidemiologia , Psychodidae/parasitologia , Brasil/epidemiologia
10.
Artigo em Inglês | MEDLINE | ID: mdl-36542026

RESUMO

BACKGROUND: The emergence of Trypanosoma cruzi infection via oral transmission has a habitual character in its primitive endemic cycle. Recent findings revealed the first death by oral transmission of T. cruzi in the state of Espírito Santo, Brazil, in 2012, which was recorded in the rural area of Guarapari. This study evaluated the characteristics related to the occurrence of natural T. cruzi infection among dogs from the rural areas of Alegre and Iconha, municipalities of Espírito Santo. METHODS: Logistic regression analysis of factors contributing to serological detection of T. cruzi in dogs was performed in environments where Espírito Santo's Department of Health Surveillance had previously notified triatomines positive for Trypanosoma spp. from 2014 to 2017. RESULTS: A total of 36 dogs were analyzed, of which 10 (27.77%) tested positive, one was borderline (2.79%), and 25 tested negative (69.44%) for T. cruzi infection. São Caetano, a district from the Iconha municipality, presented a 25 times greater chance for the detection of positive tests (OR:25; 95% CI; 2.37->100). Dogs with updated mandatory vaccination presented with a lower risk of positive serodiagnosis (OR:0.12; 95% CI: 0.02-0.63). CONCLUSIONS: Our results highlight for the first time the occurrence of natural T. cruzi canine infection, detected in the municipality of Iconha, mainly among dogs with un-updated mandatory vaccines in the district of São Caetano.


Assuntos
Doença de Chagas , Trypanosoma cruzi , Animais , Cães , Brasil/epidemiologia , Insetos Vetores , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Doença de Chagas/veterinária
11.
Malar J ; 21(1): 399, 2022 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-36585690

RESUMO

BACKGROUND: Anopheles maculatus, Anopheles minimus and Anopheles dirus are the major vectors of malaria transmission in the Greater Mekong Subregion (GMS). The malaria burden in this region has decreased significantly in recent years as all GMS countries progress towards malaria elimination. It is necessary to investigate the Anopheles diversity and abundance status and assess the Plasmodium infection rates to understand the malaria transmission potential of these vector species in GMS countries to guide the development of up-to-date vector control strategies and interventions. METHODS: A survey of mosquitoes was conducted in Stung Treng, Sainyabuli and Phongsaly Provinces on the Cambodia-Laos, Thailand-Laos and China-Laos borders, respectively. Mosquito collection was done by overnight trapping at sentinel sites in each province. After morphological identification, the 18S rRNA-based nested-PCR was performed to detect malaria parasites in the captured Anopheles mosquitoes. RESULTS: A total of 18 965 mosquitoes comprising of 35 species of 2 subgenera (Subgenus Anopheles and Subgenus Cellia) and 4 tribes (Tribes Culicini, Aedini, Armigerini and Mansoniini) were captured. Tribe Culicini accounted for 85.66% of captures, followed by Subgenus Anopheles (8.15%). Anopheles sinensis dominated the Subgenus Anopheles by 99.81%. Plasmodium-infection was found in 25 out of the 1 683 individual or pooled samples of Anopheles. Among the 25 positive samples, 19, 5 and 1 were collected from Loum, Pangkhom and Siem Pang village, respectively. Eight Anopheles species were found infected with Plasmodium, i.e., An. sinensis, Anopheles kochi, Anopheles vagus, An. minimus, Anopheles annularis, Anopheles philippinensis, Anopheles tessellatus and An. dirus. The infection rates of Plasmodium falciparum, Plasmodium vivax and mixture of Plasmodium parasite species were 0.12% (2/1 683), 1.31% (22/1 683) and 0.06% (1/1 683), respectively. CONCLUSIONS: Overall, this survey re-confirmed that multiple Anopheles species carry malaria parasites in the international border areas of the GMS countries. Anopheles sinensis dominated the Anopheles collections and as carriers of malaria parasites, therefore may play a significant role in malaria transmission. More extensive investigations of malaria vectors are required to reveal the detailed vector biology, ecology, behaviour, and genetics in GMS regions in order to assist with the planning and implementation of improved malaria control strategies.


Assuntos
Anopheles , Malária , Plasmodium , Animais , Malária/prevenção & controle , Anopheles/parasitologia , Tailândia/epidemiologia , Laos , Camboja , Insetos Vetores/parasitologia , Mosquitos Vetores , China
12.
Parasit Vectors ; 15(1): 491, 2022 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-36578020

RESUMO

BACKGROUND: With the largest cattle population in Africa and vast swathes of fertile lands infested by tsetse flies, trypanosomosis is a major challenge for Ethiopian farmers. Managing the problem strategically and rationally requires comprehensive and detailed information on disease and vector distribution at the national level. To this end, the National Institute for Control and Eradication of Tsetse and Trypanosomosis (NICETT) developed a national atlas of tsetse and African animal trypanosomosis (AAT) for Ethiopia. METHODS: This first edition of the atlas focused on the tsetse-infested areas in western Ethiopia. Data were collected between 2010 and 2019 in the framework of national surveillance and control activities. Over 88,000 animals, mostly cattle, were tested with the buffy-coat technique (BCT). Odour-enhanced traps were deployed in approximately 14,500 locations for the entomological surveys. Animal- and trap-level data were geo-referenced, harmonized and centralized in a single database. RESULTS: AAT occurrence was confirmed in 86% of the districts surveyed (107/124). An overall prevalence of 4.8% was detected by BCT in cattle. The mean packed cell volume (PCV) of positive animals was 22.4, compared to 26.1 of the negative. Trypanosoma congolense was responsible for 61.9% of infections, T. vivax for 35.9% and T. brucei for 1.7%. Four tsetse species were found to have a wide geographic distribution. The highest apparent density (AD) was reported for Glossina pallidipes in the Southern Nations, Nationalities and People's Region (SNNPR) (3.57 flies/trap/day). Glossina tachinoides was the most abundant in Amhara (AD 2.39), Benishangul-Gumuz (2.38), Gambela (1.16) and Oromia (0.94) regions. Glossina fuscipes fuscipes and G. morsitans submorsitans were detected at lower densities (0.19 and 0.42 respectively). Only one specimen of G. longipennis was captured. CONCLUSIONS: The atlas establishes a reference for the distribution of tsetse and AAT in Ethiopia. It also provides crucial evidence to plan surveillance and monitor control activities at the national level. Future work on the atlas will focus on the inclusion of data collected by other stakeholders, the broadening of the coverage to tsetse-free areas and continuous updates. The extension of the atlas to data on control activities is also envisaged.


Assuntos
Tripanossomíase Africana , Tripanossomíase , Moscas Tsé-Tsé , Animais , Bovinos , Etiópia/epidemiologia , Insetos Vetores , Tripanossomíase Africana/epidemiologia , Tripanossomíase Africana/prevenção & controle , Tripanossomíase Africana/veterinária
13.
J Vector Borne Dis ; 59(3): 236-240, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36511039

RESUMO

BACKGROUND & OBJECTIVES: The state of Himachal Pradesh is one of the hilly forested states of India. Warming of climate has been evidenced in the state due to the ongoing climate change which may cause the upsurge/introduction of mosquito-borne diseases. To curb disease transmission, an effective vector control strategy will be required. METHODS: Insecticide susceptibility status of available malaria vectors was determined using the standard WHO method in six districts Kangra, Una, Mandi, Bilaspur, Solan and Mandi of the state. An. culicifacies and An. fluviatilis were tested against DDT (4%), malathion (5%) and deltamethrin (0.05%) using WHO insecticide susceptibility kits. RESULTS: Overall, An. culicifacies was found resistant to DDT in all the six districts, susceptible to malathion in all districts except Bilaspur and Solan where it showed possible resistance. It was susceptible to deltamethrin in all the study districts. An. fluviatilis was resistant to DDT and susceptible to malathion and deltamethrin in Kangra and Una districts. INTERPRETATION & CONCLUSION: At present, indoor residual spraying (IRS) is not being undertaken in Himachal Pradesh. However, with the information generated through the present study, the state government can plan evidence-based IRS at least for focal spray in limited foci reporting malaria incidence.


Assuntos
Anopheles , Inseticidas , Malária , Piretrinas , Animais , Humanos , Inseticidas/farmacologia , Malária/epidemiologia , Malária/prevenção & controle , Resistência a Inseticidas , Piretrinas/farmacologia , Controle de Mosquitos/métodos , DDT/farmacologia , Insetos Vetores , Mosquitos Vetores , Malation/farmacologia , Índia/epidemiologia
14.
J Vector Borne Dis ; 59(3): 253-258, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36511042

RESUMO

BACKGROUND & OBJECTIVES: An. annularis van der Wulp (1884) is the secondary malaria vector of importance in India. In Jharkhand state it is present in almost all the districts abundantly and transmits malaria. The development of resistance to Dichlorodipheny ltrichloroethane (DDT) in An. annularis was reported from various parts of India. The main objective of this study was to generate information on insecticide susceptibility status of An. annularis to DDT, malathion, deltamethrin and permethrin in different districts of Jharkhand state. Methods; Adult An. annularis female mosquitoes were collected form villages of six tribal districts Simdega (Kurdeg and Simdega CHC), Khunti (Murhu and Khunti CHCs), Gumla (Bharno and Gumla CHCs), West Singhbhum (Chaibasa and Bada Jamda CHCs), Godda (Poraiyahat and Sunderpahari (CHCs) and Sahibganj (Borio and Rajmahal CHCs). Insecticide susceptibility status was determined by using WHO tube test method against prescribed discriminatory dosages of insecticides, DDT - 4.0%, malathion - 5.0%, deltamethrin - 0.05% and permethrin - 0.75%. RESULTS: An. annularis was reported resistant to DDT in six districts, possible resistant to malathion in districts Gumla, Khuntiand Sahibganj and susceptible to deltamehrin (98% to100% mortality) and permethrin (100% mortality). INTERPRETATION & CONCLUSION: An. annularis, the secondary vector species is associated with the transmission of malaria reported resistant to DDT and susceptible to pyrerthroids deltamethrin and permethrin. In view of large-scale distribution of long-lasting insecticidal nets (LLINs) in all the districts, the response to synthetic pyrethroid needs to be periodically monitored to assess the effectiveness.


Assuntos
Anopheles , Inseticidas , Malária , Piretrinas , Animais , Feminino , Inseticidas/farmacologia , Malária/epidemiologia , Malária/prevenção & controle , Resistência a Inseticidas , DDT/farmacologia , Insetos Vetores , Nitrilas/farmacologia , Mosquitos Vetores , Malation/farmacologia , Permetrina/farmacologia
15.
ScientificWorldJournal ; 2022: 5098005, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36408197

RESUMO

Leishmaniasis is a parasitosis caused by parasites of the genus Leishmania and is transmitted by Phlebotominae sand flies. An entomological survey was carried out in different localities of Zagora Province. Our work allowed us to establish an inventory of sand flies to study potential vectors of leishmaniasis and to compare the composition and the specific abundance of different endemic stations. The sand flies were collected using CDC miniature light traps during the month of July 2019 in the ten studied villages. The results indicate the presence of thirteen species, belonging to the genera Phlebotomus and Sergentomyia. Phlebotomus papatasi was the predominant species (46.65%) followed by Ph. alexandri (17%), Ph. longicuspis (11.55%), Ph. bergeroti (1.53%) and Ph. sergenti (1.27%). Phlebotomus kazeruni (0.03%) was rare, and only one female was captured in Ifred. Sergentomyia schwetzi (8.69%) was the most prevalent species in the Sergentomyia genus followed closely by Se. fallax (6.84%). Sergentomyia africana was present with a proportion of (3.86%) followed by Se. clydei (1.96%). Sergentomyia dreifussi (0.46%), Se. antennata (0.08%), and Se. minuta (0.08%) were very limited. Phlebotomus papatasi, Ph. alexandri, Ph. bergeroti, Ph. longicuspis, Ph. sergenti, Se. schwetzi, Se. clydei, and Se. fallax are constant species, being present at least in 50% of the stations (occurrence> 50%). Common species (25%-49%) were Se. minuta and Se. africana and rare species were Ph. kazeruni and Se. antennata with a very limited distribution (occurrence <12%). The greatest species richness was found in Ksar Mougni and Ifred with the occurrence of 11 species, but overall, it was high (>9 species) in most of the villages. The Shannon-Wiener index was high (H' > 1) in eight localities (Ksar Mougni, Tassaouante, Bleida, ZaouiteLeftah, Ifred, Timarighine, Ait Oulahyane, and Ait Ali Ouhassou). The high value of this index is in favor of the ZaouiteLeftah locality (Shannon-Wiener index = 1.679) which is explained by the presence of a stand dominated by Ph. papatasi. In order to avoid exposure to infections, a good epidemiological surveillance and vector with rodent control measures must be well maintained. Awareness campaigns are also required and must be conducted for better knowledge of the disease.


Assuntos
Leishmaniose Cutânea , Phlebotomus , Psychodidae , Animais , Feminino , Marrocos/epidemiologia , Insetos Vetores/parasitologia , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologia , Phlebotomus/parasitologia
16.
J Invertebr Pathol ; 195: 107850, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36347390

RESUMO

A significant amount of work has been devoted towards understanding the cellular and humoral immune responses in arthropod vectors. Although fleas (Siphonaptera) are vectors of numerous bacterial pathogens, few studies have examined how these insects defend themselves from infection. In this study, we investigated the immune defense mechanisms in the hemocoel of cat fleas (Ctenocephalides felis), currently the most important flea pest of humans and many domestic animals. Using model species of bacteria (Micrococcus luteus, Serratia marcescens, and Escherichia coli), we delivered a systemic infection and measured the following: antimicrobial activity of hemolymph, levels of free radicals resulting from the induction of oxidase-based pathways, number of circulating hemocytes, phagocytosis activity of circulating hemocytes, and in vivo bacteria killing efficiency when phagocytosis activity is limited. Our results show that the antimicrobial activity of flea hemolymph increases in response to certain species of bacteria; yet, a systemic infection with the same bacterial species did not influence levels of hydrogen peroxide (H2O2), a reactive intermediate of oxygen, at the same time. Additionally, the number of circulating hemocytes increases in response to E. coli infection, and these cells display strong phagocytic activity against this bacterium. Moreover, limiting phagocytosis by injecting polystyrene beads subsequently increases flea susceptibility to E. coli infection when compared to injury controls; however, impairing the cellular immune response itself did not increase flea susceptibility to infection when compared to untreated fleas. Overall, this work yields significant insight into how fleas interact with bacterial pathogens in their hemocoel, and suggests that cellular and humoral immune responses cooperate to combat systemic bacterial infections.


Assuntos
Anti-Infecciosos , Infecções Bacterianas , Doenças do Gato , Ctenocephalides , Infecções por Escherichia coli , Infestações por Pulgas , Gatos , Humanos , Animais , Ctenocephalides/microbiologia , Escherichia coli , Peróxido de Hidrogênio , Insetos Vetores/microbiologia , Bactérias , Infecções por Escherichia coli/veterinária , Mecanismos de Defesa
17.
Vet Clin North Am Small Anim Pract ; 52(6): 1267-1281, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36336420

RESUMO

Veterinary Chagas disease is a persistent threat to humans, dogs, and other wild or domestic mammals that live where infected triatomine "kissing bug" insect vectors occur across the Americas, including 28 states in the Southern United States. Animals infected with the Trypanosoma cruzi parasite may be asymptomatic or may develop myocarditis, heart failure, and sudden death. It is difficult to prevent animal contact with vectors because they are endemic in sylvatic environments and often disperse to domestic habitats. Challenges for disease management include imperfect diagnostic tests and limited antiparasitic treatment options.


Assuntos
Doença de Chagas , Doenças do Cão , Triatoma , Trypanosoma cruzi , Animais , Estados Unidos/epidemiologia , Humanos , Cães , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Doença de Chagas/terapia , Doença de Chagas/veterinária , Triatoma/parasitologia , Trypanosoma cruzi/parasitologia , Insetos Vetores/parasitologia , Mamíferos/parasitologia , Doenças do Cão/diagnóstico , Doenças do Cão/epidemiologia , Doenças do Cão/terapia
18.
Front Cell Infect Microbiol ; 12: 999082, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36329821

RESUMO

Background: Rhodnius prolixus is considered the most relevant Trypanosoma cruzi vector in Colombia and Venezuela due it is responsible for domestic transmission in both countries. However, a wild population of this species is distributed in the eastern plains of the Orinoco region and Amazonia jungle, where its epidemiological importance has not been sufficiently elucidated. This study aimed to assess epidemiological parameters of T. cruzi transmission in the Department of Vichada, Colombia. Methods: We determined the characteristics of T. cruzi transmission using entomological studies in domestic and sylvatic ecotopes. We analyzed the T. cruzi infection in triatomine insects, identified blood meal sources, and conducted a serological determination of T. cruzi infection in scholar-aged children, domestic dogs, and wild hosts. Results: Fifty-four triatomine bugs, 40 T. maculata and 14 R. prolixus were collected in peridomestic and sylvatic ecotopes. Infected R. prolixus was observed in La Primavera, Santa Rosalia, and Cumaribo municipalities. All the T. maculata bugs were not infected. Serological analysis indicated that two of 3,425 children were T. cruzi positive. The seroprevalence in domestic dogs was 10,5% (49/465). Moreover, 22 synanthropic mammals were sampled, being Didelphis marsupialis the most common. TcI genotype was detected in seropositive dogs, R. prolixus, and D. marsupialis. Conclusion: The present work describes extra domestic R. prolixus and D. marsupialis in a sylvatic T. cruzi transmission cycle with transmission to humans and domestic dogs in Colombia's Vichada Department.


Assuntos
Doença de Chagas , Rhodnius , Trypanosoma cruzi , Criança , Humanos , Cães , Animais , Idoso , Estudos Soroepidemiológicos , Colômbia/epidemiologia , Insetos Vetores , Doença de Chagas/epidemiologia , Doença de Chagas/veterinária , Trypanosoma cruzi/genética , Mamíferos
19.
PLoS Negl Trop Dis ; 16(11): e0010684, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36331979

RESUMO

BACKGROUND: The objective of this study was to characterise the vector in a small hyper-endemic focus of onchocerciasis (the Kakoi-Koda focus) which has recently been discovered on the western slopes of the rift valley above Lake Albert. METHODOLOGY/PRINCIPAL FINDINGS: Aquatic stages of blackflies were collected by hand from streams and rivers, and anthropophilic adult females were collected by human landing catches. Using a combination of morphotaxonomy and DNA barcoding, the blackflies collected biting humans within the focus were identified as Simulium dentulosum and Simulium vorax, which were also found breeding in local streams and rivers. Simulium damnosum s.l., Simulium neavei and Simulium albivirgulatum were not found (except for a single site in 2009 where crabs were carrying S. neavei). Anthropophilic specimens from the focus were screened for Onchocerca DNA using discriminant qualitative real-time triplex PCR. One specimen of S. vorax was positive for Onchocerca volvulus in the body, and out of 155 S. dentulosum, 30% and 11% were infected and infective (respectively). CONCLUSIONS/SIGNIFICANCE: Simulium dentulosum currently appears to be the main vector of human onchocerciasis within the Kakoi-Koda focus, and S. vorax may be a secondary vector. It remains possible that S. neavei was the main (or only) vector in the past having now become rare as a result of the removal of tree-cover and land-use changes. Simulium vorax has previously been shown to support the development of O. volvulus in the laboratory, but this is the first time that S. dentulosum has been implicated as a probable vector of onchocerciasis, and this raises the possibility that other blackfly species which are not generally considered to be anthropophilic vectors might become vectors under suitable conditions. Because S. dentulosum is not a vector in endemic areas surrounding the Kakoi-Koda focus, it is probable that the Kakoi-Koda focus is significantly isolated.


Assuntos
Onchocerca volvulus , Oncocercose , Simuliidae , Adulto , Animais , Feminino , Humanos , Oncocercose/epidemiologia , República Democrática do Congo/epidemiologia , Insetos Vetores , Melhoramento Vegetal , Simuliidae/genética
20.
Parasit Vectors ; 15(1): 399, 2022 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-36316748

RESUMO

BACKGROUND: The aims of the present study were to evaluate and compare the efficacy of blood-feeding in phlebotomines through industrially processed membranes from the small intestine of pigs (used for the production of commercial sausages) and the skin of euthanized chicks. METHODS: Laboratory-bred Lutzomyia longipalpis and different field-caught phlebotomine species were subjected to the artificial feeding systems under similar conditions. Paired tests were performed using the control (skin from euthanized chicks) and test membranes (pig small intestine). The feeding rates were compared by paired t-test, and Pearson correlation was used to examine the relationship between the thickness of the membranes and feeding rate. RESULTS: The feeding rate was greater with the test membrane than with the control membrane for L. longipalpis (t-test, t = -3.3860, P = 0.0054) but not for the most frequent field-caught species, Nyssomyia antunesi (t-test, t = 0.7746, P = 0.4535). The average thicknesses of the control and test membranes were 184 ± 83 µm and 34 ± 12 µm, respectively (Mann-Whitney U-test, U = 0.00, Z = 2.8823, P = 0.0039); however, there was no correlation between feeding rate and membrane thickness. A moderate positive correlation was observed between the number of phlebotomines that fed and the total number of phlebotomines in the cage for each type of membrane and for each species. CONCLUSIONS: The test membrane is a viable alternative for the artificial blood-feeding of phlebotomines, and is thus a potential substitute for the skin of animals that are euthanized for this purpose. Feeding rate was independent of membrane thickness.


Assuntos
Substitutos Sanguíneos , Psychodidae , Animais , Suínos , Insetos Vetores , Apoio Nutricional , Brasil
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