Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 34
Filtrar
1.
Parasitol Res ; 122(9): 2237-2241, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37462744

RESUMO

Cryptosporidium parvum is the second-most prevalent Cryptosporidium species that infects humans worldwide. In European countries, it is the most prevalent species in sheep, suggesting that these animals are a source of zoonotic infection. Preweaned lambs and goats are particularly susceptible to infection by the parasite and may suffer from severe diarrhea whilst excreting large quantities of infectious oocysts. Fifty fecal samples from preweaned lambs and goats with diarrhea from 35 farms across Israel, found to be Cryptosporidium-positive by microscopy, were tested by PCR and sequence analyses to determine the infective species and subtypes. Cryptosporidium parvum DNA was detected in most samples from both lambs and goats (46/50). Cryptosporidium xiaoi DNA was detected in three samples from kids, with co-infection detected in a single sample. Eleven different C. parvum subtypes were found, 10 in lambs and 5 in goats. All subtypes were from the IIa and IId subtype families, with subtypes IIdA20G1 and IIaA15G2R1 being the most prevalent and widespread. These subtypes were previously found in calves and humans in Israel and are considered the most prevalent C. parvum subtypes in small ruminants globally. These results underline the zoonotic potential of C. parvum from small ruminants and the high subtype diversity compared to previous reports from other Middle Eastern countries. In addition, this is the first report of C. xiaoi in Israel.


Assuntos
Doenças dos Bovinos , Criptosporidiose , Cryptosporidium parvum , Cryptosporidium , Animais , Humanos , Ovinos , Bovinos , Cryptosporidium parvum/genética , Cryptosporidium/genética , Criptosporidiose/epidemiologia , Criptosporidiose/parasitologia , Cabras/parasitologia , Israel/epidemiologia , Fezes/parasitologia , Diarreia/epidemiologia , Diarreia/veterinária , Diarreia/parasitologia , Genótipo
2.
Emerg Infect Dis ; 27(8): 2197-2200, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34287129

RESUMO

We discuss genomic detection of Schmallenberg virus in both Culicoides midges and affected ruminants during June 2018-December 2019, demonstrating its circulation in Israel. This region is a geographic bridge between 3 continents and may serve as an epidemiologic bridge for potential Schmallenberg virus spread into Asia.


Assuntos
Infecções por Bunyaviridae , Ceratopogonidae , Orthobunyavirus , Animais , Ásia , Infecções por Bunyaviridae/epidemiologia , Infecções por Bunyaviridae/veterinária , Genômica , Insetos Vetores , Israel/epidemiologia , Orthobunyavirus/genética
3.
BMC Microbiol ; 19(1): 311, 2019 12 30.
Artigo em Inglês | MEDLINE | ID: mdl-31888482

RESUMO

BACKGROUND: Many phytophagous insects, whose diet is generally nitrogen-poor, rely on gut bacteria to compensate for nutritional deficits. Accordingly, we hypothesized that insects in desert environments may evolve associations with gut bacteria to adapt to the extremely low nutrient availability. For this, we conducted a systematic survey of bacterial communities in the guts of weevils developing inside mud chambers affixed to plant roots in the Negev Desert of Israel, based on 16S rRNA gene amplicon sequencing. RESULTS: Our analyses revealed that gut bacterial communities in weevil larvae were similar across a wide geographical range, but differed significantly from those of the mud chambers and of the surrounding soils. Nevertheless, a high proportion of bacteria (including all of the core bacteria) found in the weevils were also detected in the mud chambers and soils at low relative abundances. The genus Citrobacter (of the Enterobacteriaceae family) was the predominant group in the guts of all individual weevils. The relative abundance of Citrobacter significantly decreased at the pupal and adult stages, while bacterial diversity increased. A mini literature survey revealed that members of the genus Citrobacter are associated with nitrogen fixation, recycling of uric acid nitrogen, and cellulose degradation in different insects. CONCLUSIONS: The results suggest that although weevils could potentially acquire their gut bacteria from the soil, weevil host internal factors, rather than external environmental factors, were more important in shaping their gut bacterial communities, and suggest a major role for Citrobacter in weevil nutrition in this challenging environment. This study highlights the potential involvement of gut bacteria in the adaptation of insects to nutritional deficiencies under extreme desert conditions.


Assuntos
Bactérias/classificação , Clima Desértico , Microbioma Gastrointestinal , Raízes de Plantas , Gorgulhos/microbiologia , Animais , Bactérias/isolamento & purificação , Israel , Larva/microbiologia , Nitrogênio/metabolismo , RNA Ribossômico 16S/genética , Salsola , Análise de Sequência de DNA , Solo , Microbiologia do Solo , Simbiose , Gorgulhos/fisiologia
4.
Emerg Infect Dis ; 24(7): 1335-1339, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29912703

RESUMO

Whole-genome sequencing unveiled host and environment-related insights to Shigella sonnei transmission within cyclic epidemics during 2000-2012 in Israel. The Israeli reservoir contains isolates belonging to S. sonnei lineage III but of different origin, shows loss of tetracycline resistance genes, and little genetic variation within the O antigen: highly relevant for Shigella vaccine development.


Assuntos
Surtos de Doenças , Disenteria Bacilar/epidemiologia , Disenteria Bacilar/transmissão , Evolução Molecular , Shigella sonnei/genética , Disenteria Bacilar/microbiologia , Genoma Bacteriano , Humanos , Israel/epidemiologia , Vigilância em Saúde Pública , Shigella sonnei/classificação , Sequenciamento Completo do Genoma
5.
Emerg Infect Dis ; 22(9): 1545-53, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27532625

RESUMO

Shigellae are sensitive indicator species for studying trends in the international transmission of antimicrobial-resistant Enterobacteriaceae. Orthodox Jewish communities (OJCs) are a known risk group for shigellosis; Shigella sonnei is cyclically epidemic in OJCs in Israel, and sporadic outbreaks occur in OJCs elsewhere. We generated whole-genome sequences for 437 isolates of S. sonnei from OJCs and non-OJCs collected over 22 years in Europe (the United Kingdom, France, and Belgium), the United States, Canada, and Israel and analyzed these within a known global genomic context. Through phylogenetic and genomic analysis, we showed that strains from outbreaks in OJCs outside of Israel are distinct from strains in the general population and relate to a single multidrug-resistant sublineage of S. sonnei that prevails in Israel. Further Bayesian phylogenetic analysis showed that this strain emerged approximately 30 years ago, demonstrating the speed at which antimicrobial drug-resistant pathogens can spread widely through geographically dispersed, but internationally connected, communities.


Assuntos
Antibacterianos/farmacologia , Infecções Comunitárias Adquiridas/epidemiologia , Infecções Comunitárias Adquiridas/transmissão , Farmacorresistência Bacteriana Múltipla , Disenteria Bacilar/epidemiologia , Disenteria Bacilar/transmissão , Judeus , Shigella sonnei/efeitos dos fármacos , Viagem , Antibacterianos/uso terapêutico , Infecções Comunitárias Adquiridas/história , Infecções Comunitárias Adquiridas/microbiologia , Surtos de Doenças , Disenteria Bacilar/história , Disenteria Bacilar/microbiologia , Genes Bacterianos , Genoma Bacteriano , Saúde Global , História do Século XX , História do Século XXI , Humanos , Testes de Sensibilidade Microbiana , Vigilância da População , Fatores de Risco , Shigella sonnei/classificação , Shigella sonnei/genética , Shigella sonnei/isolamento & purificação , Sequenciamento Completo do Genoma
6.
Sci Rep ; 14(1): 16148, 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-38997329

RESUMO

This study investigates the morphological changes in grape pips resulting from various charring conditions. Employing high-resolution scanning combined with morphometric measurements for morphological analysis, we aimed to understand the effects of charring on grape pips. Our morphometric analysis demonstrated significant alterations in seed shape above 250 °C. The length-width ratio and the occurrence of cracks notably changed, providing a basis for assessing charring conditions. In addition, applying a machine learning classification method, we determined that accurate classification of grape varieties by the morphometric analysis method is feasible for seeds charred at up to 250 °C and 8 h. Integrating the morphometric changes and temperature ranges suitable for classification, we developed a sorting model for archaeological seeds. By projecting length-width ratios onto a curve calculated from controlled conditions, we estimated charring temperatures. Approximately 50% of archaeological seeds deviated from the model, indicating drastic charring conditions. This sorting model facilitates a stringent selection of seeds fit for classification, enhancing the accuracy of our machine learning-based methodology. In conclusion, combining machine learning with morphometric sorting enables the identification of charred grape seeds suitable for identification by the morphometric method. This comprehensive approach provides a valuable tool for future research for the identification of charred grape seeds found in archaeological contexts, enhancing our understanding of ancient viticulture practices and grape cultivation.

7.
Appl Environ Microbiol ; 79(1): 303-13, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23104413

RESUMO

The Mediterranean fruit fly (medfly) (Ceratitis capitata) lays eggs in fruits, where larvae subsequently develop, causing large-scale agricultural damage. Within its digestive tract, the fly supports an extended bacterial community that is composed of multiple strains of a variety of enterobacterial species. Most of these bacteria appear to be functionally redundant, with most strains sustaining diazotrophy and/or pectinolysis. At least some of these bacteria were shown to be vertically inherited, but colonization, structural, and metabolic aspects of the community's dynamics have not been investigated. We used fluorescent in situ hybridization, metabolic profiling, plate cultures, and pyrosequencing to show that an initial, egg-borne, diverse community expands throughout the fly's life cycle. While keeping "core" diazotrophic and pectinolytic functions, it also harbors diverse and fluctuating populations that express varied metabolic capabilities. We suggest that the metabolic and compositional plasticity of the fly's microbiota provides potential adaptive advantages to the medfly host and that its acquisition and dynamics are affected by mixed processes that include stochastic effects, host behavior, and molecular barriers.


Assuntos
Bactérias/classificação , Bactérias/metabolismo , Biota , Ceratitis capitata/microbiologia , Animais , DNA Bacteriano/genética , DNA Ribossômico/genética , Trato Gastrointestinal/microbiologia , Fixação de Nitrogênio , Pectinas/metabolismo , Dinâmica Populacional , RNA Ribossômico 16S/genética
8.
Vet Sci ; 10(11)2023 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-37999468

RESUMO

Bovine ephemeral fever virus (BEFV) is an arthropod-borne virus (arbovirus) transmitted by blood-feeding insects (mosquitoes and Culicoides biting midges). While the dispersal of arboviral diseases such as bovine ephemeral fever (BEF) into naive areas is often the result of globalization and animal movement, the endemization and local outbreaks of these diseases are mainly influenced by environmental changes. Climate change affects the activity, distribution, dynamics, and life cycles of these vectors (arthropods), the replication of viruses within their vectors, and weakens animal's immune systems. Although BEF does not currently occur in the Americas and Europe (other than in the western regions of Turkey), the risk of BEFV emergence, spread, and endemization in Europe is real. Over the past two decades, arboviruses such as the bluetongue virus (BTV) and Schmallenberg virus (SBV) have emerged in Europe without warning and caused significant losses to the dairy and meat industries. Since the European cattle population has never been exposed to BEFV, the economic losses to dairy and beef production in this continent due to the reduction in milk production, loss of valuable cows, and abortion, should BEF emerge, would probably be considerable. Moreover, arboviruses can also cause substantial financial damage due to restrictions on animal trade and transportation, like the current EHDV-8 outbreak in the Mediterranean basin. In this study, we used national data stored in the Israeli herd book to examine the economic aspects of BEF outbreaks in affected dairy cattle farms countrywide. Our results demonstrate that BEF outbreaks can have immediate and delayed effects, causing severe economic losses due to culling (loss of valuable cows) and a reduction in milk production that affects dairy farm income for months after clinical diagnosis. To our knowledge, this is the first extensive study on the impact of a BEF outbreak at a population level, enabling to conduct accurate risk assessments in future cases of BEFV emergence and re-emergence.

9.
Heliyon ; 9(9): e18831, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37674833

RESUMO

Biological invasions pose a serious threat to local flora and fauna and have negative impacts on ecosystems. Invasive parasites can also cause severe losses in aquaculture. In this article, we provide evidence of the recent spillover of an African parasite with a complex, three-host life cycle that has rapidly and successfully established itself in the Middle East, most likely due to the recent migration of its final hosts (great cormorant) from Africa. This case of parasite introduction into a country with intensive aquaculture is also important from an economic point of view, since large (up to 2 cm long) larvae of this parasite, the cyclophyllidean tapeworm Amirthalingamia macracantha (Cestoda) localised in the liver, can be pathogenic to their fish hosts, including farmed and wild fish, as shown by our histopathological examination of heavily infected fish. Since its first detection in Israel in November 2020, the parasite has spread rapidly and is currently found in both migratory (great cormorant, Phalacrocorax carbo) and non-migratory birds (pygmy cormorant, Microcarbo pygmaeus), as well as in fish intermediate hosts, including farmed tilapia in several farms in Israel and wild cichlids. There are numerous examples of the spillover of introduced parasites, including those that parasitise fish of commercial importance, but have a direct life cycle or use only a single intermediate host. Tilapines are the second most important group of farmed fish in the world after carps and are produced mainly in Southeast Asia, Central and South America. The global spread of great cormorants and the early evidence that pygmy cormorant may also harbour A. macracantha pose the risk of further spread of this invasive parasite to other countries and areas. In addition, global warming and reductions in foraging and resting areas near these waters may allow the parasite to complete its life cycle in new hosts.

10.
PLoS One ; 18(10): e0289424, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37812593

RESUMO

Burnt materials are very common in the archaeological record. Their identification and the reconstruction of their firing history are crucial for reliable archaeological interpretations. Commonly used methods are limited in their ability to identify and estimate heating temperatures below ~500°C and cannot reconstruct the orientation in which these materials were burnt. Stepwise thermal demagnetization is widely used in archaeomagnetism, but its use for identifying burnt materials and reconstructing paleotemperatures requires further experimental verification. Here we present an experimental test that has indicated that this method is useful for identifying the firing of mud bricks to 190°C or higher. Application of the method to oriented samples also enables reconstruction of the position in which they cooled down. Our algorithm for interpreting thermal demagnetization results was tested on 49 miniature sun-dried "mud bricks", 46 of which were heated to a range of temperatures between 100°C to 700°C under a controlled magnetic field and three "bricks" which were not heated and used as a control group. The results enabled distinguishing between unheated material and material heated to at least 190°C and accurately recovering the minimum heating temperature of the latter. Fourier-Transform Infrared Spectroscopy (FTIR) on the same materials demonstrated how the two methods complement each other. We implemented the thermal demagnetization method on burnt materials from an Iron Age structure at Tell es-Safi/Gath (central Israel), which led to a revision of the previously published understanding of this archaeological context. We demonstrated that the conflagration occurred within the structure, and not only in its vicinity as previously suggested. We also showed that a previously published hypothesis that bricks were fired in a kiln prior to construction is very unlikely. Finally, we conclude that the destruction of the structure occurred in a single event and not in stages over several decades.


Assuntos
Materiais de Construção , Temperatura Alta , Argila , Temperatura , Arqueologia/métodos
11.
Acta Trop ; 246: 106995, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37549840

RESUMO

Bovine ephemeral fever (BEF) is a significant viral disease of cattle in the tropical, subtropical, and temperate climatic zones. This disease is also known as three-day sickness due to the spontaneous recovery of the cattle within a short period (usually 3-5 days). Despite its short duration, the disease may have a considerable impact. It can cause heavy economic losses, primarily due to decreased milk production, lowered fertility in bulls, and even fatality in severe cases. The virus is suspected to be transmitted by haematophagous insects (mainly mosquitoes and Culicoides biting midges); however, the identity of a competent vector for BEFV remains a mystery. Here, we investigated whether BEFV may replicate for a short duration in Culex pipiens Linnaeus, 1758, the most prevalent mosquito species in Israel and a potential vector of this virus to Israeli cattle. We applied nested- qPCR to test BEFV abundance in Cx. pipiens every 24 h for 14 consecutive days post-infection. Additionally, we collected eggs laid by BEFV-infected females and investigated BEFV abundance in the different developmental stages of F1 mosquitos. Our results suggest that Cx. pipiens mosquitoes have the potential to act as a vector of BEFV and also indicate that BEFV may be vertically transmitted from Cx. pipiens female parent to her female offspring.


Assuntos
Ceratopogonidae , Culex , Vírus da Febre Efêmera Bovina , Febre Efêmera , Animais , Bovinos , Feminino , Masculino , Mosquitos Vetores , Israel
12.
Vet Sci ; 9(2)2022 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-35202318

RESUMO

Outbreaks of arthropod-borne (arbo) viruses that infect livestock impact the health and welfare of domestic and wild animals are often responsible for significant economic losses in livestock production. Surveillance and early warning systems effectively predict the emergence and re-emergence of arboviral disease. This paper presents the interim results of five years monitoring the exposure of sentinel naïve heifers and Culicoides biting midges (Diptera; Ceratopogonidae) to bovine ephemeral fever virus (BEFV), Simbu serogroup viruses, bluetongue viruses (BTV), and epizootic hemorrhagic disease viruses (EHDV). The data were collected from 11 dairy farms situated within eight different geographical regions in Israel. The results indicate that cattle in Israel are affected by all four viruses from the early summer onward. The investigated viruses exhibit unique site-specific profiles in both ruminants and vectors. The potential of several vectors to transmit these viruses and lack of cross-protection to re-infection with multiple serotypes (BTV and EHDV) or species (Simbu serogroup viruses) highlights some likely mechanisms that may play a role in these viruses' maintenance cycle and possible endemization in our region.

13.
Viruses ; 13(11)2021 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-34834956

RESUMO

Important lessons have been learned by the Israeli veterinary community regarding Simbu serogroup viruses infections. This serogroup of viruses might cause the births of neonatal malformation in susceptible ruminant's populations. Until 2012, only Akabane virus was connected with the births of malformed ruminants in Israel. However, serological and genomic detection tests, coupled with viral isolations, revealed that more than a single Simbu serogroup serotype could be present concurrently in the same farm or even in the same animal. From 2012 to date, Aino, Shuni, Shamunda, Satuperi, Peaton, Schmallenberg, and Sango viruses have been found in Israel either by serological or genomic investigation. Israel is located in the Eastern Mediterranean Basin, a terrestrial and climatic bridge between the three old continents. The Eastern Mediterranean shores benefit from both the tropical/subtropical and the continental climatic conditions. Therefore, the Eastern Mediterranean basin might serve as an optimal investigatory compound for several arboviral diseases, acting as a sentinel. This review summarizes updated information related to the presence of Simbu serogroup viruses in Israel.


Assuntos
Infecções por Bunyaviridae/transmissão , Infecções por Bunyaviridae/virologia , Clima , Gado/virologia , Vírus Simbu , Animais , Infecções por Arbovirus/epidemiologia , Infecções por Arbovirus/transmissão , Infecções por Arbovirus/virologia , Infecções por Bunyaviridae/epidemiologia , Bovinos , Doenças dos Bovinos/virologia , Doenças Transmissíveis Emergentes , Surtos de Doenças/veterinária , Israel , Orthobunyavirus , Ruminantes/virologia , Sorogrupo , Ovinos , Doenças dos Ovinos/virologia , Vírus Simbu/classificação , Vírus Simbu/genética , Vírus Simbu/isolamento & purificação
14.
J Virol Methods ; 296: 114229, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34245790

RESUMO

The enveloped flavivirus Israel turkey meningoencephalitis virus (ITV) causes a neuroparalytic disease in adult turkeys leading to morbidity and mortality. This study reevaluates the role of blood-sucking insects in the transmission of ITV. We demonstrate the crucial importance of two factors in detecting viruses carried by blood-sucking insects: first, enhanced molecular detection of ITV in insects by nested qRT-PCR and second, collection and maintenance of live insects until their molecular examination. These upgrades allowed overcoming the small virus quantities contained in the insects and detecting ITV for the first time in field-collected Culex pipiens.


Assuntos
Culex , Flavivirus , Animais , Flavivirus/genética , Reação em Cadeia da Polimerase , Perus
15.
Transbound Emerg Dis ; 68(6): 3025-3033, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33314697

RESUMO

Tilapia lake virus (TiLV) is an emerging viral disease that affects several tilapia species in different countries since 2014. In 2017-2018, 129 samples were collected from 14 tilapia farms in Israel. Ninety samples represented mortality events (ME), and 39 were used as control samples (CS). RT-qPCR was performed on 89 and 39 duplicate brain and liver tissue samples from ME samples and CS, respectively. TiLV was diagnosed in 37 (41.6%) ME, while only two of the CS samples (5%) were positive for TiLV (OR = 13.2, 95% CI = 3.0-58.1). Additional RT-PCR was performed on positive samples, and amplified products were sequenced. Maximum likelihood phylogenetic analysis of segment-3 revealed three distinct clades: the first clade (A) includes 25 sequences of TiLV, detected previously in Israel (2011), Ecuador (2012), Egypt (2015), Thailand (2015-2019), India (2017), Peru (2018) and USA (2018-2019) and 11 sequences of TiLV from the current study (2017-2018); the second clade (B) includes only four sequences from Thailand (2018) and Bangladesh (2017 and 2019); and a third clade (C) which includes a single sequence from Bangladesh (2019). Out of the 39 sequences included in clade A, 14 closely related sequences of TiLV from the current study (2018) formed a distinctive sub-clade (IL-2018). Mann-Whitney U test showed differences in the distribution of survival rates between Israeli sequences (from 2011, 2017 and 2018) of clade A (p = 0.004) and Israeli sequences (from 2018 solely) of sub-clade IL-2018. The average survival rates of clade A and sub-clade IL-2018 were 58.1% (SD = 21.5) and 31.2% (SD = 25.6), respectively. This is one of only few field studies which show direct association of TiLV with mortality events in tilapia farms. The decrease in survival rate in the newly evolved clade might raise concern regarding virus evolution towards increased virulence, which should be further explored.


Assuntos
Doenças dos Peixes , Infecções por Orthomyxoviridae , Tilápia , Animais , Doenças dos Peixes/epidemiologia , Israel/epidemiologia , Infecções por Orthomyxoviridae/veterinária , Filogenia
16.
Vet Parasitol Reg Stud Reports ; 25: 100608, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34474801

RESUMO

Cryptosporidium are protozoan parasites with worldwide distribution, infecting a wide range of terrestrial and aquatic animals, as well as humans. Cryptosporidium parvum is the most important zoonotic species and is the primary cause of cryptosporidiosis in preweaned calves, a highly prevalent, economically important disease. Extensive subtyping of C. parvum from infected humans and animals has expanded current understanding of the parasites' epidemiology. Israel has a highly developed dairy sector with intensive, zero-grazing operations. While C. parvum has been found in dairy calves throughout the country, and subtype data from human patients have also been published, subtype data from animals, and in particular preweaned ruminants, are lacking. We carried out an initial study of Cryptosporidium species and subtypes from preweaned diarrheic calves. Cryptosporidium species were determined in 71 fecal samples from 43 different dairy farms using 18S rRNA PCR, and subtyping of C. parvum based on the 60-kDa glycoprotein (gp60) sequences was done on one sample per farm. C. parvum was the only species found, with eight different subtypes belonging to the zoonotic IIa and IId families. Subtype IIaA15G2R1 was the most prevalent and widespread, found in 50% of the farms over a wide geographical distribution. Our results confirm the presence of subtypes IIaA15G2R1 and IIdA20G1, which were previously found in human patients in Israel, also in Israeli calves. In addition, subtype IIaA12G1R1 is reported here for the first time in an animal. These findings demonstrate the value of monitoring C. parvum subtypes in animal samples, and suggest that the role of calves as well as other young ruminants in the transmission of zoonotic cryptosporidiosis in Israel should be further studied.


Assuntos
Doenças dos Bovinos , Criptosporidiose , Cryptosporidium parvum , Cryptosporidium , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Criptosporidiose/epidemiologia , Criptosporidiose/parasitologia , Cryptosporidium/genética , Cryptosporidium parvum/genética , Humanos , Israel/epidemiologia
18.
Appl Environ Microbiol ; 76(7): 2280-5, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20139311

RESUMO

Many species of Rickettsia are well-known mammalian pathogens transmitted by blood-feeding arthropods. However, molecular surveys are continually uncovering novel Rickettsia species, often in unexpected hosts, including many arthropods that do not feed on blood. This study reports a systematic molecular characterization of a Rickettsia infecting the psocid Liposcelis bostrychophila (Psocoptera: Liposcelidae), a common and cosmopolitan household pest. Surprisingly, the psocid Rickettsia is shown to be Rickettsia felis, a human pathogen transmitted by fleas that causes serious morbidity and occasional mortality. The plasmid from the psocid R. felis was sequenced and was found to be virtually identical to the one in R. felis from fleas. As Liposcelis insects are often intimately associated with humans and other vertebrates, it is speculated that they acquired R. felis from fleas. Whether the R. felis in psocids causes disease in vertebrates is not known and warrants further study.


Assuntos
Insetos/microbiologia , Rickettsia felis/genética , Rickettsia felis/isolamento & purificação , Animais , Proteínas de Bactérias/genética , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Características da Família , Humanos , Dados de Sequência Molecular , Filogenia , Plasmídeos , RNA Ribossômico 16S/genética , Rickettsia felis/classificação , Análise de Sequência de DNA
19.
Insect Sci ; 27(3): 392-403, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31207108

RESUMO

Many insects feed on a low-nitrogen diet, and the origin of their nitrogen supply is poorly understood. It has been hypothesized that some insects rely on nitrogen-fixing bacteria (diazotrophs) to supplement their diets. Nitrogen fixation by diazotrophs has been extensively studied and convincingly demonstrated in termites, while evidence for the occurrence and role of nitrogen fixation in the diet of other insects is less conclusive. Here, we summarize the methods to detect nitrogen fixation in insects and review the available evidence for its occurrence (focusing on insects other than termites). We distinguish between three aspects of nitrogen fixation investigations: (i) detecting the presence of potential diazotrophs; (ii) detecting the activity of the nitrogen-fixing enzyme; and (iii) detecting the assimilation of fixed nitrogen into the insect tissues. We show that although evidence from investigations of the first aspect reveals ample opportunities for interactions with potential diazotrophs in a variety of insects, demonstrations of actual biological nitrogen fixation and the assimilation of fixed nitrogen are restricted to very few insect groups, including wood-feeding beetles, fruit flies, leafcutter ants, and a wood wasp. We then discuss potential implications for the insect's fitness and for the ecosystem as a whole. We suggest that combining these multiple approaches is crucial for the study of nitrogen fixation in insects, and argue that further demonstrations are desperately needed in order to determine the relative importance of diazotrophs for insect diet and fitness, as well as to evaluate their overall impact on the ecosystem.


Assuntos
Bactérias/metabolismo , Insetos/microbiologia , Insetos/fisiologia , Fixação de Nitrogênio , Nitrogênio/metabolismo , Animais , Besouros/microbiologia , Besouros/fisiologia , Dieta , Dípteros/microbiologia , Dípteros/fisiologia , Ecossistema , Microbioma Gastrointestinal , Hemípteros/microbiologia , Hemípteros/fisiologia , Isópteros/microbiologia , Isópteros/fisiologia
20.
Front Microbiol ; 11: 493, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32390951

RESUMO

Obligatory hematophagous arthropods such as lice, bugs, flies, and ticks harbor bacterial endosymbionts that are expected to complement missing essential nutrients in their diet. Genomic and some experimental evidence support this expectation. Hard ticks (Acari: Ixodidae) are associated with several lineages of bacterial symbionts, and very few were experimentally shown to be essential to some aspects of tick's fitness. In order to pinpoint the nature of interactions between hard ticks and their symbionts, we tested the effect of massive elimination of Coxiella-like endosymbionts (CLE) by antibiotics on the development and fitness of the brown dog tick (Rhipicephalus sanguineus). Administration of ofloxacin to engorged (blood fed) nymphs resulted in significant and acute reduction of their CLE loads - an effect that also persisted in subsequent life stages (aposymbiotic ticks). As a result, the post-feeding development of aposymbiotic female (but not male) nymphs was delayed. Additionally, aposymbiotic adult females needed a significantly prolonged feeding period in order to replete (detach from host), and had reduced engorgement weight and a lower capacity to produce eggs. Consequently, their fecundity and fertility were significantly reduced. Eggs produced by aposymbiotic females were free of CLE, and the resulting aposymbiotic larvae were unable to feed successfully. Our findings demonstrate that the observed fitness effects are due to CLE reduction and not due to antibiotic administration. Additionally, we suggest that the contribution of CLE is not mandatory for oocyte development and embryogenesis, but is required during feeding in females, when blood meal processing and tissue buildup are taking place. Presumably, under these extreme physiological demands, CLE contribute to R. sanguineus through supplementing essential micro- and macronutrients. Further nutrient complementary studies are required to support this hypothesis.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA