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3.
PLoS Negl Trop Dis ; 14(8): e0008415, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32804951

RESUMO

Basic and translational research on loiasis, a filarial nematode infection of medical importance, is impeded by a lack of suitable Loa loa infection models and techniques of obtaining and culturing life cycle stages. We describe the development of a new method for routine production of infective third-stage larvae (L3) of L. loa from the natural intermediate arthropod vector host, Chrysops silacea, following experimental infection with purified microfilariae. At 14-days post-infection of C. silacea, the fly survival rate was 43%. Survival was significantly higher in flies injected with 50 mf (55.2%) than those that received 100 mf (31.0%). However, yield per surviving fly and total yield of L3 was markedly higher in the group of flies inoculated with 100 mf (3474 vs 2462 L3 produced). The abdominal segment hosted the highest percentage recovery of L3 (47.7%) followed by head (34.5%) and thorax (17.9%). L. loa larval survival was higher than 90% after 30 days of in vitro culture. The in vitro moulting success rate to the L4 larval stage was 59.1%. After experimental infection of RAG2-/-IL-2γc-/-mice, the average L. loa juvenile adult worm recovery rate was 10.5% at 62 dpi. More than 87% of the worms were recovered from the muscles and subcutaneous tissues. Worms recovered measured an average 24.3 mm and 11.4 mm in length for females (n = 5) and males (n = 5), respectively. In conclusion, L. loa mf injected into C. silacea intrathoracically develop into infective larvae that remain viable and infective comparable to L3 obtained through natural feeding on the human host. This technique further advances the development of a full laboratory life cycle of L. loa where mf derived from experimentally-infected animals may be utilized to passage life cycle generations via intrathoracic injections of wild-caught vector hosts.


Assuntos
Dípteros/parasitologia , Vetores de Doenças , Larva/parasitologia , Loa/isolamento & purificação , Loíase/parasitologia , Animais , Modelos Animais de Doenças , Feminino , Humanos , Larva/crescimento & desenvolvimento , Estágios do Ciclo de Vida , Loa/citologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microfilárias , Taxa de Sobrevida
4.
Exp Parasitol ; 217: 107960, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32755552

RESUMO

Guinea worm Dracunculus medinensis causes debilitating disease in people and is subject to an ongoing global eradication programme. Research and controls are constrained by a lack of diagnostic tools. We developed a specific and sensitive LAMP method for detecting D. medinensis larval DNA in copepod vectors. We were able to detect a single larva in a background of field-collected copepods. This method could form the basis of a "pond-side test" for detecting potential sources of Guinea worm infection in the environment, in copepods, including in the guts of fish as potential transport hosts, enabling research, surveillance and targeting of control measures. The key constraint on the utility of this assay as a field diagnostic, is a lack of knowledge of variation in the temporal and spatial distribution of D. medinensis larvae in copepods in water bodies in the affected areas and how best to sample copepods to obtain a reliable diagnostic sample. These fundamental knowledge gaps could readily be addressed with field collections of samples across areas experiencing a range of worm infection frequencies, coupled with field and laboratory analyses using LAMP and PCR.


Assuntos
Copépodes/parasitologia , Dracunculus/isolamento & purificação , Técnicas de Diagnóstico Molecular/normas , Técnicas de Amplificação de Ácido Nucleico/normas , Tanques/parasitologia , África , Animais , Sequência de Bases , Gatos , Copépodes/genética , Primers do DNA/química , DNA de Helmintos/isolamento & purificação , Vetores de Doenças , Cães , Dracunculus/genética , Humanos , Papio , Sensibilidade e Especificidade , Fatores de Tempo
5.
PLoS Genet ; 16(7): e1008856, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32614824

RESUMO

The microRNAs (miRNAs) are important regulators of gene expression. In this study, we provide evidence for the first time to show that rickettsial pathogen Anaplasma phagocytophilum infection results in the down-regulation of tick microRNA-133 (miR-133), to induce Ixodes scapularis organic anion transporting polypeptide (isoatp4056) gene expression critical for this bacterial survival in the vector and for its transmission to the vertebrate host. Transfection studies with recombinant constructs containing transcriptional fusions confirmed binding of miR-133 to isoatp4056 mRNA. Treatment with miR-133 inhibitor resulted in increased bacterial burden and isoatp4056 expression in ticks and tick cells. In contrast, treatment with miR-133 mimic or pre-mir-133 resulted in dramatic reduction in isoatp4056 expression and bacterial burden in ticks and tick cells. Moreover, treatment of ticks with pre-mir-133 affected vector-mediated A. phagocytophilum infection of murine host. These results provide novel insights to understand impact of modulation of tick miRNAs on pathogen colonization in the vector and their transmission to infect the vertebrate host.


Assuntos
Anaplasma phagocytophilum/genética , Interações Hospedeiro-Patógeno/genética , Ixodes/genética , MicroRNAs/genética , Anaplasma phagocytophilum/patogenicidade , Animais , Apoptose , Vetores de Doenças , Regulação da Expressão Gênica/genética , Genes Essenciais/genética , Humanos , Insetos Vetores/genética , Ixodes/patogenicidade , Camundongos , Transportadores de Ânions Orgânicos/genética , Peptídeos/genética , Transcriptoma/genética
6.
PLoS One ; 15(7): e0229314, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32706777

RESUMO

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


Assuntos
Aedes/metabolismo , Ração Animal/análise , Anticorpos Antivirais/análise , Testes de Neutralização/métodos , Vírus do Rio Ross/imunologia , Aedes/virologia , Infecções por Alphavirus/diagnóstico , Infecções por Alphavirus/transmissão , Infecções por Alphavirus/veterinária , Ração Animal/virologia , Animais , Anticorpos Antivirais/sangue , Vetores de Doenças , Feminino , Humanos , Phascolarctidae/virologia , Sensibilidade e Especificidade
8.
Rev. Hosp. Ital. B. Aires (2004) ; 40(2): 63-75, jun. 2020. graf, ilus, tab
Artigo em Espanhol | LILACS | ID: biblio-1102739

RESUMO

El objetivo de este artículo es proporcionar una guía que sirva para la interpretación y seguimiento de los esfuerzos que se están desarrollando en todo el mundo con el objetivo de obtener una vacuna que pueda generar inmunidad contra el nuevo coronavirus SARS-CoV-2 de 2019, el agente causante de la enfermedad por coronavirus denominada COVID-19. Cinco meses después de haber sido detectada la enfermedad, ya hay 102 vacunas en distintos estadios de desarrollo, registradas por la Organización Mundial de la Salud (OMS), correspondientes a 8 plataformas vacunales con diferentes estrategias, y todos los días aparecen nuevas. Esto representará un enorme desafío de organismos internacionales, para la evaluación, comparación y selección de aquellas que cumplan con los criterios regulatorios indispensables de seguridad y eficacia y que, por otro lado, puedan ser producidas en cantidades suficientes para abastecer la demanda mundial. (AU)


The objective of this article is to provide a guide to help the interpretation and monitoring the efforts that are being carried out worldwide to obtain a vaccine that will be able to generate immunity against the new 2019 SARS-CoV-2 coronavirus, the viral agent causes the disease named COVID-19. Five months after the disease was detected, there are already 102 vaccines at different stages of development, registered by World Health Organization (WHO), corresponding to 8 vaccination platforms base on different strategies, and every day new ones appear. This will represent a huge challenge for international organizations, to evaluate, compare and selects those that will meet the essential regulatory criteria of safety and efficacy and that, would be able to be produced in enough quantities to supply the worldwide demand. Key words: SARS-Cov-2 vaccine, vaccine platform, COVID-19 strategy, attenuated virus, viral vector, viral proteins, viral DNA, viral RNA, nucleic acids, viral like particles, WHO. (AU)


Assuntos
Humanos , Masculino , Feminino , Infecções por Coronavirus/terapia , Vírus da SARS/imunologia , Pneumonia Viral/terapia , DNA/uso terapêutico , RNA/uso terapêutico , Vacinas/uso terapêutico , Ácidos Nucleicos/uso terapêutico , Proteína S/imunologia , Infecções por Coronavirus/virologia , Vírus da SARS/fisiologia , Vírus da SARS/genética , Vetores de Doenças
10.
Parasitol Res ; 119(7): 2347-2350, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32488623

RESUMO

Thelazia callipaeda (Spirurida, Thelaziidae) is a vector-borne zoonotic eyeworm able to infect a broad spectrum of carnivores. Here, we describe the first case of bilateral infection by T. callipaeda in the eyes of an adult female Iberian wolf (Canis lupus signatus) in central Spain. Nematodes collected were morphologically identified (n = 42), and two specimens were molecularly characterized. At the sequence analysis of the partial mitochondrial cytochrome c oxidase subunit 1 gene, T. callipaeda haplotype 1 (the only haplotype circulating in Europe) was detected. The role of the Iberian wolf as a natural reservoir for T. callipaeda in the life cycle of this emerging zoonosis and the implications in conservation are discussed.


Assuntos
Olho/parasitologia , Infecções por Spirurida/veterinária , Thelazioidea/isolamento & purificação , Lobos/parasitologia , Animais , Vetores de Doenças , Complexo IV da Cadeia de Transporte de Elétrons/genética , Europa (Continente) , Feminino , Genes Mitocondriais/genética , Haplótipos/genética , Humanos , Masculino , Espanha , Thelazioidea/genética , Zoonoses/parasitologia
12.
PLoS Negl Trop Dis ; 14(6): e0008350, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32569337

RESUMO

BACKGROUND: The arboviral vector Aedes albopictus became established on all continents except Antarctica in the past 50 years. A consequence of its rapid global invasion is the transmission of diseases previously confined to the tropics and subtropics occurring in temperate regions of the world, including the re-emergence of chikungunya and dengue in Europe. Application of pyrethroids is among the most widely-used interventions for vector control, especially in the presence of an arboviral outbreak. Studies are emerging that reveal phenotypic resistance and monitor mutations at the target site, the para sodium channel gene, primarily on a local scale. METHODS: A total of 512 Ae. albopictus mosquitoes from twelve geographic sites, including those from the native home range and invaded areas, were sampled between 2011 and 2018, and were analyzed at five codons of the para sodium channel gene with mutations predictive of resistance phenotype. Additionally, to test for the origin of unique kdr mutations in Mexico, we analyzed the genetic connectivity of southern Mexico mosquitoes with mosquitoes from home range, the Reunion Island, America and Europe. RESULTS: We detected mutations at all tested positions of the para sodium channel gene, with heterozygotes predominating and rare instance of double mutants. We observed an increase in the distribution and frequency of F1534C/L/S mutations in the ancestral China population and populations in the Mediterranean Greece, the appearance of the V1016G/I mutations as early as 2011 in Italy and mutations at position 410 and 989 in Mexico. The analyses of the distribution pattern of kdr alleles and haplotype network analyses showed evidence for multiple origins of all kdr mutations. CONCLUSIONS: Here we provide the most-up-to-date survey on the geographic and temporal distribution of pyrethroid-predictive mutations in Ae. albopictus by combining kdr genotyping on current and historical samples with published data. While we confirm low levels of pyrethroid resistance in most analyzed samples, we find increasing frequencies of F1534C/S and V1016G in China and Greece or Italy, respectively. The observed patterns of kdr allele distribution support the hypothesis that on site emergence of resistance has contributed more than spread of resistance through mosquito migration/invasions to the current widespread of kdr alleles, emphasizing the importance of local surveillance programs and resistance management.


Assuntos
Aedes/efeitos dos fármacos , Aedes/genética , Resistência a Inseticidas/genética , Piretrinas/farmacologia , Alelos , Animais , Arbovirus , Vetores de Doenças , Variação Genética , Genótipo , Haplótipos , Proteínas de Insetos/genética , Inseticidas/farmacologia , Mosquitos Vetores/genética , Mutação/efeitos dos fármacos , Canais de Sódio/genética
13.
PLoS Negl Trop Dis ; 14(6): e0008310, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32511225

RESUMO

Schistosomes infect more than 200 million people worldwide, and globally, over 700 million people are at risk of infection. The snail Biomphalaria straminea, as one of the intermediate hosts of Schistosoma mansoni, consecutively invaded Hong Kong in 1973, raising great concern in China. In this study, a malacological survey was conducted over a period of four years, and investigations were performed on the mechanism of susceptibility of B. straminea to S. mansoni. B. straminea was investigated in China from 2014 to 2018. Out of 185 investigated sites, 61 were positive for stages of black B. straminea (BBS), which shows pigmented spots. Twenty of the 61 sites were positive for red B. straminea (RBS), which is partially albino and red colored. Phylogenetic analyses based on cox1 and 18S rRNA sequences demonstrated that both phenotypes were clustered with Brazilian strains. No S. mansoni infections were detected in field-collected snail. However, in laboratory experiments, 4.17% of RBS were susceptible to a Puerto Rican strain of S. mansoni, while BBS was not susceptible. The highest susceptibility rate (70.83%) was observed in the F2 generation of RBS in lab. The density of RBS has increased from south to north and from west to east in Guangdong since 2014. Five tyrosinase tyrosine metabolism genes were upregulated in BBS. Transcriptome comparisons of RBS and BBS showed that ficolin, C1q, MASP-like, and membrane attack complex (MAC)/perforin models of the complement system were significantly upregulated in BBS. Our study demonstrated that B. straminea is widely distributed in Hong Kong and Guangdong Province, which is expanding northwards very rapidly as a consequence of its adaptation to local environments. Our results suggest that B. straminea from South China is susceptible to S. mansoni, implying the high potential for S. mansoni transmission and increased S. mansoni infection risk in China.


Assuntos
Biomphalaria/parasitologia , Água Doce/parasitologia , Schistosoma mansoni/isolamento & purificação , Esquistossomose mansoni/transmissão , Animais , China/epidemiologia , Vetores de Doenças , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Filogenia , Esquistossomose mansoni/epidemiologia
15.
Korean J Parasitol ; 58(2): 153-159, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32418384

RESUMO

The chigger mite Leptotrombidium sialkotense is one of the 6 main vectors of scrub typhus in China. Before present study, L. sialkotense was found in some parts of Hunan province, China with a narrow geographical distribution. During field investigation 2016-2017, we found L. sialkotense in Jingha, southern Yunnan, China. Of 15 small mammal host species, L. sialkotense were collected from 6 species of the hosts. Rattus brunneusculus was a dominant host of L. sialkotense, from which 98.3% of the mites were collected. The chigger mite showed a relatively high infestation prevalence (PM=11.7%) and mean abundance (MA=0.5) in comparison with the rest 5 host species. These results reveal a certain host specificity of L. sialkotense to a rat R. brunneusculus. The mite L. sialkotense showed an aggregated distribution on the host (P<0.05). A positive correlation observed between L. sialkotense and the body length of hosts. There was a positive interspecific association between L. sialkotense and 2 other dominant vectors, L. deliense and L. scutellare.


Assuntos
Vetores de Doenças , Tifo por Ácaros/parasitologia , Trombiculidae , Animais , China/epidemiologia , Interações Hospedeiro-Parasita , Ratos , Tifo por Ácaros/epidemiologia
16.
Phytopathology ; 110(9): 1565-1571, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32378451

RESUMO

Breeding for varieties carrying natural resistance (R) against plant-parasitic nematodes is a promising alternative to nematicide ban. In perennial crops, the long plant-nematode interaction increases the risk for R breaking and R durability is a real challenge. In grapevine, the nematode Xiphinema index has a high economic impact by transmitting Grapevine fanleaf virus (GFLV) and, to delay GFLV transmission, rootstocks resistant to this vector are being selected, using Muscadinia rotundifolia in particular as an R source. To optimize in fine this strategy, the durability has been studied under controlled conditions in F1 and BC1 muscadine-derived resistant accessions previously obtained from either hardwood-cutting or in vitro propagation. After inoculation with a mix, in equal proportions, of four lines representative of the X. index diversity, multiplication on plants has been monitored 3 to 6 years. The nematode reproduction factor remained lower than 1 in resistant plants obtained from hardwood cuttings while it increased at values far beyond 1 in resistant plants of in vitro origin. Data for nematode numbers per gram of roots mostly paralleled those obtained for the reproduction factor. The effect of the propagation type on resistance over years was also evaluated for the ratio female/juvenile and the frequency of males. Altogether our results illustrate that the muscadine-derived resistance based on hardwood cuttings is durable. By contrast, in resistant and reference accessions obtained from in vitro, our data suggest that the increased nematode multiplication might be mainly due to the modification of root architecture consecutive to this propagation method.


Assuntos
Nematoides , Vitis , Animais , Cruzamento , Vetores de Doenças , Feminino , Doenças das Plantas
17.
PLoS One ; 15(5): e0232616, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32379806

RESUMO

Bemisia tabaci (sensu latu) is a group of >40 highly cryptic whitefly species that are of global agricultural importance, both as crop pests and plant-virus vectors. Two devastating cassava diseases in East and Central Africa are spread by abundant populations of one of these species termed Sub-Saharan Africa 1 (SSA1). There is a substantive risk that these whitefly-borne pandemics will continue to spread westwards and disrupt cassava production for millions of smallholder farmers in West Africa. We report here, therefore, the first comprehensive survey of cassava B. tabaci in eastern Nigeria, a West African region likely to be the first affected by the arrival of these whitefly-borne pandemics. We found one haplotype comprising 32 individuals with 100% identical mtCO1 sequence to the East African SSA1 populations (previously termed SSA1-SG1) and 19 mtCO1 haplotypes of Sub-Saharan Africa 3 (SSA3), the latter being the most prevalent and widely distributed B. tabaci species in eastern Nigeria. A more divergent SSA1 mtCO1 sequence (previously termed SSA1-SG5) was also identified in the region, as were mtCO1 sequences identifying the presence of the MED ASL B. tabaci species and Bemisia afer. Although B. tabaci SSA1 was found in eastern Nigeria, they were not present in the high abundances associated with the cassava mosaic (CMD) and cassava brown streak disease (CBSD) pandemics of East and Central Africa. Also, no severe CMD or any CBSD symptoms were found in the region.


Assuntos
Vetores de Doenças/classificação , Hemípteros/classificação , Doenças das Plantas , Animais , Haplótipos , Hemípteros/genética , Hemípteros/patogenicidade , Manihot/crescimento & desenvolvimento , Nigéria , Filogenia
18.
PLoS One ; 15(5): e0233269, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32469894

RESUMO

BACKGROUND: Vector-borne diseases are a public health problem in Colombia, where dengue virus infection is hyperendemic. The introduction of other arboviruses, such as chikungunya and Zika in the last three years, has aggravated the situation. Mobile health (mHealth) offers new strategies for strengthening health care and surveillance systems promoting the collection, delivery, and access of health information to professionals, researchers, and patients. Assessing mobile application performance has been a challenge in low- and middle-income countries due to the difficulty of implementing these technologies in different clinical settings. In this study, we evaluate the usability and acceptability of a mobile application, FeverDX, as a support tool in the management of patients with febrile syndrome and suspected arboviruses infection by general practitioners from Colombia. METHODS: A pilot implementation study was conducted to evaluate the usability and acceptability of FeverDX using the modified version of the Mobile Application Rating Scale (uMARS). The evaluation form included 25 questions regarding quantity and quality of information, engagement, functionality, aesthetics, impact, and acceptability by healthcare workers. Each item uses a 5-point scale (1-Inadequate, 2-Poor, 3-Acceptable, 4-Good, 5-Excellent). A global score was obtained for the evaluation form test by determining the median scores of each subsection. A descriptive statistical analysis of the data obtained was performed. RESULTS: Between December 2016 and January 2017, a total of 20 general practitioners from the Emergency room and hospitalization areas evaluated FeverDX. Less than half (9/20) of the evaluators had a comprehensive knowledge of the Colombian Ministry of Health's guidelines for the diagnosis and management of arboviruses, and evaluators partially (4/9) or completely (5/9) agreed that the content of the application follows the management guidelines. On uMARS scale, FeverDX excelled regarding impact (median 5; IQR = 5-5), functionality (median 5; IQR = 4.8-5), and information and scientific basis (median 4; IQR = 4-4). FeverDX scored well regarding user feedback (median 4; IQR = 4-4.5), design and aesthetics (median 4; IQR = 4-4.3), and subjective assessment of quality (median 4.5; IQR = 4.3-4.8). CONCLUSIONS: FeverDX, a mobile application, is a novel mHealth strategy to strengthen care processes and facilitate the detection and reporting of notifiable surveillance diseases. It could improve adherence to clinical practice guidelines for the management and prevention of prevalent diseases as arboviruses in healthcare settings. Although this pilot study used a small sample size, FeverDx performed adequately in a simulated emergency consultation. Further implementation studies are needed to increase the reliability of mHealth technologies in different scenarios.


Assuntos
Assistência à Saúde/normas , Pessoal de Saúde/normas , Implementação de Plano de Saúde , Aplicativos Móveis/normas , Telemedicina/normas , Doenças Transmitidas por Vetores/diagnóstico , Doenças Transmitidas por Vetores/terapia , Animais , Colômbia/epidemiologia , Vetores de Doenças , Pessoal de Saúde/psicologia , Humanos , Aplicativos Móveis/estatística & dados numéricos , Projetos Piloto , Inquéritos e Questionários , Doenças Transmitidas por Vetores/epidemiologia
19.
PLoS One ; 15(5): e0233014, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32433657

RESUMO

Citrus trees produce flushes throughout the year, but there are no criteria established for a precise shoot monitoring in orchards under tropical climate. Methods for quantification of flush dynamics would be useful for horticultural and pest management studies because different insect vectors feed and reproduce on flushes. We estimated the minimum number and distribution of trees for sampling and determined the flushing pattern over time in 'Valencia Late' orange trees grafted onto 'Swingle' citrumelo rootstock. Shoots within a square frame (0.25 m2) on two sides of the canopy were counted and classified by their phenological stage. The minimum number of samples was estimated using the mean number of shoots and area under the flush shoot dynamics (AUFSD). The temporal and spatial distribution analysis was performed by Taylor's power law and by multiple correspondence analysis (MCA). Additionally, a shoot maturity index (SMI) based on visual qualitative assessment of flushes is proposed. Considering the mean number of shoots, it was necessary to sample two sides of 16 trees to reach a relative sampling error (Er) of 25%, whereas by the AUFSD, only five trees were necessary to reach an Er of 10%. Flushes were predominantly randomly distributed over time and space. Testing eight transects, sampled trees should be distributed throughout the block, avoiding sampling concentration in a certain area. MCA showed that the west side and the upper sampling positions of trees were more likely to be associated with younger shoots. AUFSD and the evaluation of both sides of the canopy yielded a smaller number of trees to be assessed. The SMI was a reliable metric to estimate the shoot phenology of orange trees, and correlated well (R2 > 70%) with the mean number of shoots within the square frame. Therefore, SMI has the potential to make shoot monitoring in the field more practical.


Assuntos
Citrus/crescimento & desenvolvimento , Animais , Brasil , Citrus/parasitologia , Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/parasitologia , Produtos Agrícolas/crescimento & desenvolvimento , Vetores de Doenças , Monitorização de Parâmetros Ecológicos , Interações Hospedeiro-Patógeno , Controle de Pragas/métodos , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Brotos de Planta/crescimento & desenvolvimento , Tamanho da Amostra , Clima Tropical , Tempo (Meteorologia)
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