Common Host Research Articles

VopX, a novel Vibrio cholerae T3SS effector, modulates host actin dynamics.

Despite different infection strategies, enteric pathogens commonly employ a T3SS to colonize the human host and cause disease. Effector proteins are unique to each T3SS-encoding bacterial species and generally lack conserved amino acid sequences. However, T3SS effectors from diverse pathogens target and manipulate common host cell structures and signaling proteins, such as the actin cytoskeleton and MAPK pathway components. T3SS-encoding Vibrio cholerae strains and effectors have been relatively recently identified, and the mechanisms used to mediate colonization and secretory diarrhea are poorly understood. Two V. cholerae effectors that modify the host actin cytoskeleton were shown to be important for colonization. We therefore sought to determine the target(s) and mechanism of a third actin-reorganizing effector, VopX, based on results obtained from a yeast model system. We recapitulated actin-based phenotypes in multiple mammalian model systems, leading us to identify the molecular function of the V. cholerae VopX effector protein.

Development of an attenuated glutamine synthetase (GS) selection system for the stable expression of tissue plasminogen activator in CHO-K1 cells

Chinese hamster ovary (CHO) cells represent the most common host system for the expression of high-quality recombinant proteins. The development of stable CHO cell lines used in industrial recombinant protein production often relies on dihydrofolate reductase (DHFR) and glutamine synthetase (GS) amplification systems. Conventional approaches to develop stable cell lines lead to heterogeneous cell populations. Consequently, it is desirable to adopt innovative strategies to increase the efficiency of clone selection to reduce the time and effort invested in the cell line development process. Attenuating the selection marker gene is an effective strategy for isolating high-producing cells. In this study, we evaluated the efficiency of an attenuated glutamine synthetase selection system for the expression of human tissue plasminogen activator (t-PA) in CHO cells. We introduced an AU-rich element (ARE) at the 3’UTR of the glutamine synthetase coding sequence and employed a weak promoter (mSV40) for the expression of this gene. Subsequently, we analyzed the effect of ARE on the GS RNA levels, and recombinant t-PA expression. Our results demonstrate that the use of ARE significantly enhances the detection of high expressing cells compared to the control. Additionally, the t-PA expression level in GS-ARE clones was approximately 900-fold greater than those without the ARE.

Insights into host-pathogen interaction based on the comparison of genomes of leptospira interrogans isolated from dogs, humans, and a rodent in the same epidemiological context: A one health approach.

Leptospirosis is a zoonotic infectious disease that significantly impacts animal and public health. Comparative genomics can aid in understanding poorly understood aspects of leptospirosis pathogenesis, including infection mechanisms, antimicrobial resistance, and host interactions across different epidemiological scenarios. This study aimed to compare the genomes of Leptospira interrogans serogroup Icterohaemorrhagiae strains isolated from three host species in a single epidemiological scenario. Four strains of L. interrogans serogroup Icterohaemorrhagiae from naturally infected and clinically symptomatic dogs (C20, C29, C51, and C82) were processed for whole genome sequencing (WGS). These results were compared against WGS data from two other rodent and human strains. Phylogenetic and genomic similarity analyses demonstrated high identity and synteny between the strains isolated from humans, canines, and rodents. Small regions of divergence were observed, especially in the genome obtained from a rodent sample. The presence of 23 genes potentially associated with biofilm formation was notable, with the identification of missense mutations in eight genes. Considering the need to better understand the molecular basis involved in biofilm formation, it is of fundamental importance to elucidate the effect of mutations on the expression of the phenotype (biofilm) among different strains. The present findings highlight the necessity of One Health-based collaborative interventions to address the complex dynamics of leptospirosis transmission, involving both common hosts such as rodents and dogs, as well as less-recognized hosts.

Cuckoo Hosts Fine-Tune Their Egg Rejection After Experiencing a Parasitism Event.

Recognising and rejecting parasitic eggs is one of the most common anti-parasitism strategies used by host birds. However, the egg rejection of some hosts exhibits behavioural plasticity. To investigate whether the egg rejection behaviour of host birds changes after encountering a parasitism event, we conducted egg rejection experiments on the locally most common host of the common cuckoo (Cuculus canorus), the grey bushchat (Saxicola ferreus) in Yunnan, China. When a single pure white egg of the white-rumped munia (Lonchura striata) or a blue model egg was individually added to the nest of the grey bushchat, the rejection rate for the white-rumped munia eggs was as high as 93.3%, whereas the rejection rate for the blue model egg was minimal (5.56%). However, when the grey bushchat rejected the munia egg and a blue model egg was subsequently added to its nest, the rejection rate for the blue model egg was significantly higher, reaching 54.5%. When recognised, the presence of a non-mimetic foreign egg in the nest may then act as a cue indicating high parasitism risk for the host. Consequently, the bird may intensify its inspection of nest eggs, leading to increased rejection of the previously accepted blue model eggs. Our results are consistent with the optimal acceptance threshold hypothesis, suggesting that as the parasitism risk increases, the grey bushchat adjusts its acceptance threshold for foreign eggs to become more stringent.

Development of a luminex-based assay for the detection of anti-capripoxvirus and rift valley fever virus antibodies in domestic ruminants

The three members of the genus capripoxvirus (CaPV), lumpy skin disease virus (LSDV), sheeppox virus (SPPV), and goatpox virus (GTPV) have common hosts and areas of overlapping geographical distribution with Rift Valley fever virus (RVFV). Hence, to ensure more cost-effective disease surveillance we developed and evaluated a Luminex assay for the simultaneous detection of antibodies against CaPV and RVFV in domestic ruminants. In cattle, the assay had a sensitivity (Se) of 98.7% and a specificity (Sp) of 98.3% in detecting anti-LSDV antibodies; both diagnostic parameters were 100% for the detection of anti-RVFV antibodies in this species. In sheep and goats, Se and Sp were 100% for the detection of anti-SPPV and anti-GTPV antibodies while they were 100% and 98.9%, respectively for the detection of anti-RVFV antibody. The assay did not cross react with anti-parapoxvirus antibodies of cattle, sheep, and goats. This multiplex serological assay offers a practical tool for accurate detection and monitoring of the immunological status of domestic ruminant populations against veterinary and socio-economically important capripox- and phleboviral infections, thus has the potential to aid in the strategic application of vaccination programmes.

Host preference of Anopheles stephensi mosquitoes for blood feeding in south of Iran: Insights from Multiplex-PCR analysis.

The study aims to determine the host preference for blood feeding among potential hosts of Anopheles stephensi in Iran, using the Multiplex-PCR method. An. stephensi is the primary malaria vector in urban areas of South Asia and the Middle East, including southern Iran, where approximately 30.21% of malaria cases are urban. This trend has become more evident during the recent outbreaks in Iran, driven by infections of Plasmodium falciparum, Plasmodium vivax, and as well as mixed infections. Hormozgan province, one of the most endemic areas in Iran, was selected for its critical public health significance. This study builds on the validated efficiency of Multiplex-PCR for blood meal analysis by applying it to mosquitoes in southern Iran. In 2021, mosquitoes were collected monthly from three coastal villages in Bandar Abbas county, Hormozgan province, using WHO-recommended collection methods. Blood-fed An. stephensi mosquitoes were dissected, and their stomach contents analysed via Multiplex-PCR to identify human and animal blood sources. Of 77 An. stephensi samples analysed, humans were the most common host was humans (29.9%), followed by mammals (19%), dogs (2.6%), and birds (1.3%). Mixed blood meals were detected in 34% of samples, including 23% with human and other hosts. Informal observations suggest that domestic animals such as goats, sheep, and chickens are commonly present near homes in these areas. Approximately 50% of An. stephensi blood meals were sourced from humans, with 29% exclusively from humans and 23% from mixed hosts. Domestic animals such as goats, sheep, and chickens appear to attract mosquitoes, highlighting their potential role in malaria dynamics. Zooprophylaxis, alongside existing measures like insecticide residual spraying, insecticide-treated bed nets, and personal protection strategies, may strengthen urban malaria control. Further research on the ecological and behavioural drivers of mosquito host selection in urban settings is warranted.

Sampling for disease surveillance: assessing effects on blue‐winged teal survival and recovery

AbstractOutbreaks of highly pathogenic avian influenza virus in wild animals highlight the need for disease surveillance in wild birds to improve our understanding of their role as reservoirs and dispersers, and potential threats to domestic poultry and wild bird populations. Surveillance for avian influenza varies in its approach, objectives, and coordination with other monitoring efforts. For waterfowl, a common host to avian influenza viruses, banding represents a concerted effort of capturing and marking thousands of individuals annually to estimate survival and harvest rates, but users of these data have generally taken a conservative approach to remove any banded birds from analyses that had a sample taken for disease surveillance during capture. We tested for differences in survival and encounter probabilities of blue‐winged teal (Spatula discors) marked (n = 21,702 teal) and sampled for disease surveillance (n = 4,216) during the nonbreeding season in Louisiana, USA, from 2016 to 2023. Although we found no consistent effect of collecting biological samples on survival probability, including an additional test showing no detectable effects of sampling for disease surveillance with oropharyngeal and cloacal swabs versus sampling with swabs and a syringe‐drawn blood sample, wide 95% credible intervals on the posterior survival estimates (mean 0.36 difference between upper and lower values across all year‐sex‐sampling groups; 0.44 for sampling type groups) indicated low statistical power to detect an effect. Seber recovery probability during the first interval following sampling was lower among birds sampled using swabs only, but we assume this stems from low sample sizes rather than an effect of collecting biological samples. Because recovery probabilities can vary as a function of individual covariates, we also examined direct recovery probabilities and observed no meaningful effect of disease surveillance sampling type but strong effects of capture date, suggesting the effect on Seber recovery probability may have been due to heterogeneity in exposure to natural and harvest mortality risks. Although we suggest that aligning disease surveillance sample collection efforts with landscape‐scale waterfowl banding efforts may have little effect on observed demographic rates, additional studies with larger sample sizes are likely needed to provide the statistical power necessary to formally conclude no effect of biological sampling on survival probabilities.

Complete genomes of common bacterial hosts of RNA bacteriophage Φ6.

Bacterial plant pathogens Pseudomonas savastanoi pv. phaseolicola, P. syringae pv. tomato, P. syringae pv. atrofaciens, and P. oleovorans East River isolate A serve as common laboratory hosts for bacteriophage Φ6, a widely used model organism for enveloped viruses. Here, we report complete genome sequences for strains of these bacterial hosts.

Two in one: A case study of two rhizocephalan species invading the nervous tissue of one host

AbstractCertain parasites can manipulate their hosts to enhance their own fitness and transmission success. Rhizocephalan barnacles are a notable example, inducing significant changes in their crustacean host's morphology, physiology, and behaviour. Until recently, it was believed that the spider crab Scyra aff. ferox is parasitized by a single species Sacculina pilosella in the Sea of Japan. However, previous molecular studies have revealed a complex of unrelated species, Sacculina pugettiae (fam. Sacculinidae) and Parasacculina pilosella (fam. Polyascidae). These rhizocephalans can even parasitize one host specimen simultaneously. Here, we investigated the interaction of S. pugettiae and P. pilosella with the nervous system of their common host. Species were identified based on receptacle morphology, with further validation through 18S gene phylogenetic analysis. The parasites interacted differently with the host nervous system: S. pugettiae had goblet‐shaped organs in the ganglion periphery, while P. pilosella lacked these structures, instead possessing numerous neuropil rootlets. In case of simultaneous infection, both goblet‐shaped organs and neuropil rootlets were present. Histochemistry revealed the presence of muscular rosettes in the rootlets of both species, suggesting a similar organization of the muscular system despite phylogenetic differences. Scanning electron microscopy confirmed the presence of host cell projections enveloping the rootlets. This study provides insights into the morphological features of rhizocephalan‐decapod interaction and highlights differences in their interaction with host nervous tissue between families. Our results also confirmed the loss of the goblet‐shaped organs in Polyascidae.

Metagenome-Assembled Genomes of Pig Fecal Samples in Nine European Countries: Insights into Antibiotic Resistance Genes and Viruses.

Gut microbiota plays a crucial role in the health and productivity of pigs. However, the spread of antibiotic resistance genes (ARGs) and viruses within the pig intestinal microbiota poses significant threats to animal and public health. This study utilized 181 pig samples from nine European countries and employed metagenomic assembly methods to investigate the dynamics and distribution of ARGs and viruses within the pig intestinal microbiota, aiming to observing their associations with potential bacterial hosts. We identified 4605 metagenome-assembled genomes (MAGs), corresponding to 19 bacterial phyla, 97 families, 309 genera, and a total of 449 species. Additionally, 44 MAGs were classified as archaea. Analysis of ARGs revealed 276 ARG types across 21 ARG classes, with Glycopeptide being the most abundant ARG class, followed by the class of Multidrug. Treponema D sp016293915 was identified as a primary potential bacterial host for Glycopeptide. Aligning nucleotide sequences with a viral database, we identified 1044 viruses. Among the viral genome families, Peduoviridae and Intestiviridae were the most prevalent, with CAG-914 sp000437895 being the most common potential host species for both. These findings highlight the importance of MAGs in enhancing our understanding of the gut microbiome, revealing microbial diversity, antibiotic resistance, and virus-bacteria interactions. The data analysis for the article was based on the public dataset PRJEB22062 in the European Nucleotide Archive.

Aonchotheca annulosa and Aonchotheca murissylvatici, which is which? A reappraisal of the gastrointestinal Aonchotheca (Nematoda: Capillariidae) species common in wood mice and bank voles.

Wood mice (Apodemus sylvaticus) and bank voles (Myodes glareolus) are often employed as natural study models in infectious disease ecology. Yet the identities of some elements of their parasite fauna have been subject to long-standing confusion. One instance of this relates to 2 nominal species of the capillariid nematode genus Aonchotheca: Aonchotheca annulosa (Dujardin, 1845) and A. murissylvatici (Diesing, 1851). Through literature review, analysis of recorded host- and site-specificity and tracing of taxonomic precedence, it is possible to confirm that A. annulosa is a valid species with a spicule c. 1000 microns long, a small intestinal site of infection and a wide host range centred in murine rodents (with A. sylvaticus the most common host). On the other hand, tracing the provenance of A. murissylavtici through to the works of the early naturalists reveals it is best assigned as a nomen nudum (lacking sufficient establishing description) or a junior synonym of A. annulosa and does not have precedence for the other Aonchotheca morphotype commonly found in Eurasian rodents. The first description consonant with this other morphotype, which has a short spicule (200–250 microns in length) and occurs primarily in the stomach of bank voles and other cricetids, was as Capillaria halli by Kalantarian in 1924. We thus recommend the suppression of A. murissyvatici in favour of Aonchotheca halli (Kalantarian, 1924) for this gastric-specialist short-spicule morphotype, particularly as the use of the A. murissylvatici name and its variants has previously been associated with substantial inconsistency and misidentification with A. annulosa.

Minor Hosts Have a Major Impact on the Enzootic Transmission of Borrelia burgdorferi.

In the northeast United States, subadult deer ticks feeding on white-footed mice are thought to drive the force of transmission of Borrelia burgdorferi (B. burgdorferi), the agent of Lyme disease. However, control measures targeting mice have produced inconsistent results, suggesting that other animals are significant contributors to enzootic transmission. Such contributions have previously been difficult to quantify. We used a retrotransposon-based host blood meal assay to measure the relative contribution of hosts to enzootic B. burgdorferi transmission at two insular sites in Massachusetts. Over 6 years, we identified mice and deer as the most common larval hosts at our Nantucket Island site. Infected nymphal ticks were derived mainly from mice (35%) and shrews (31%), despite shrews having fed only 12% of larvae. Deer were identified in 19% of the infected nymphs, despite their known reservoir incompetence. Shrews were consistently the most important host in our Martha's Vineyard site and were identified as the source of 41% of nymphs overall and 39% of the infected nymphs. Sciurids were variable contributors, feeding from 4% to 42% of the larval ticks each year, and contributed no infected nymphs in 2020 and as many as 83% in 2023. We conclude that host contributions to feeding larval ticks change over time and within sites and that shrews may be more influential than mice at some sites. Shrews, sciurids, and even deer may contribute to B. burgdorferi maintenance. Hosts that apparently feed a minor proportion of ticks can have a major impact on the force of B. burgdorferi transmission.

Combined oxygen and glucose oscillations distinctly change the transcriptional and physiological state of Escherichia coli.

Escherichia coli, a common microbial host for industrial bioproduction, experiences a highly dynamic environment in industrial-scale bioreactors due to significant glucose and oxygen gradients. In this study, we mimic the combined gradients of glucose and oxygen in high-throughput bioreactors to study the transcriptional response of E. coli to industrial-scale conditions. Under oscillating oxygen conditions, E. coli formed less biomass and accumulated the anaerobic by-product acetate. With respect to oxygen-responsive genes, we found that genes of the TCA cycle and of different electron transport chain complexes were differentially expressed. A global analysis of the expression data revealed that oxygen oscillations had caused a transition towards a catabolite-repressed state and upregulation of several stress-related regulatory programs. Interestingly, the transcriptional changes persisted after oxygen limitation stopped. In contrast, the changes we observed due to glucose starvation, such as induction of the stringent response, were primarily transient. Most importantly, we found that effects of combined oxygen and glucose oscillations were distinct from the ones of oxygen and substrate oscillations alone, suggesting an important interplay between the different metabolic regimes in industrial-scale bioreactors.

Common cuckoo eggs are more resistant to puncture by the host

The puncture resistance hypothesis suggests that thick-shelled eggs of parasitic birds can resist puncture-ejection by the host. However, few experiments have yet been conducted to test this hypothesis in terms of natural host behavior (e.g., pecking at foreign eggs). To explore whether the eggshells of common cuckoos (Cuculus canorus) are resistant to puncture-ejection by their common hosts, Oriental reed warblers (Acrocephalus orientalis), we designed experiments to investigate if and how breeding Oriental reed warblers peck at foreign eggs that includes common cuckoo, Oriental reed warbler and budgerigar (Melopsittacus undulatus) eggs. The results showed that, given the same frequency of egg pecking, the probability of eggshell breakage was 87.5% for eggs of the Oriental reed warbler and 0% for eggs of the common cuckoo, with a significant difference (P = 0.001, Fisher's exact test). Our study shows clearly that common cuckoos' eggshells are less susceptible to puncture-ejection than those of Oriental reed warblers and budgerigars. This indicates that the eggshells of common cuckoos can resist host Oriental reed warblers' puncture-ejection, supporting the puncture resistance hypothesis.

Molecular analysis of canine distemper virus H gene in the golden jackal (Canis aureus) population from Serbia

Canine distemper virus (CDV) is a highly contagious and often fatal disease affecting wild and domesticated carnivores. The virus is a single-stranded RNA virus from the genus Morbillivirus and the family Paramyxoviridae. While domestic dogs are the most common hosts, the virus poses a significant threat to endangered wildlife due to its broad host range. This study aimed to characterize the CDV Haemagglutinin (H) gene in golden jackals and explore the molecular evolution of the virus in an underrepresented host. A total of 88 brain samples from hunted golden jackals were tested for the presence of CDV viral nucleic acid, and the H gene of positive samples was amplified and sequenced using the Sanger method. Phylogenetic analysis, conducted using maximum likelihood methods, revealed that all Serbian sequences clustered within the Arctic lineage. Notably, the analysis identified a tyrosine (Y) at position 549 of the H protein, a mutation commonly associated with wildlife hosts, instead of the histidine (H) typically found in domestic strains. Additionally, a mutation at position 310 was observed, which could potentially affect the protein’s function and virus-host interactions. These findings provide valuable insights into the genetic diversity and evolutionary dynamics of CDV in golden jackals, with broader implications for understanding the virus’s adaptability to different hosts. Further research is needed to investigate the functional impact of these mutations, particularly their role in vaccine efficacy and disease transmission across wildlife and domestic species.

Experimental characterization and prediction of Escherichia coli host cell proteome retention during preparative chromatography.

Purification of recombinantly produced biopharmaceuticals involves removal of host cell material, such as host cell proteins (HCPs). For lysates of the common expression host Escherichia coli (E. coli) over 1500 unique proteins can be identified. Currently, understanding the behavior of individual HCPs for purification operations, such as preparative chromatography, is limited. Therefore, we aim to elucidate the elution behavior of individual HCPs from E. coli strain BLR(DE3) during chromatography. Understanding this complex mixture and knowing the chromatographic behavior of each individual HCP improves the ability for rational purification process design. Specifically, linear gradient experiments were performed using ion exchange (IEX) and hydrophobic interaction chromatography, coupled with mass spectrometry-based proteomics to map the retention of individual HCPs. We combined knowledge of protein location, function, and interaction available in literature to identify trends in elution behavior. Additionally, quantitative structure-property relationship models were trained relating the protein 3D structure to elution behavior during IEX. For the complete data set a model with a cross-validated R2 of 0.55 was constructed, that could be improved to a R2 of 0.70 by considering only monomeric proteins. Ultimately this study is a significant step toward greater process understanding.

Characterization of larval gut microbiota of two endoparasitoid wasps associated with their common host, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae).

Insect gut microbes play important roles in digestion, metabolism, development, and environmental adaptation. Parasitoid wasps are one of the most important biological control agents in pest control, while the gut microbial species compositions and the associated functions have been poorly investigated. Two endoparasitoid wasps, Cotesia vestalis and Diadromus collaris, parasitize the larval stage and pupal stage of the diamondback moth, Plutella xylostella, respectively. Using whole-genome shotgun metagenomic sequencing, we characterized the gut microbial composition, diversity, and potential functional roles associated with the two parasitoid wasp larvae. The results reveal that Proteobacteria and Firmicutes are the dominant phyla in the gut of C. vestalis and D. collaris larvae, with Rhizobium and Enterococcus being the dominant genera. The putative microbial functions associated with the two parasitoid wasps might play a virtual role in assisting in consuming the host's nutritional composition. The enriched CAZymes family genes are primarily involved in the degradation and synthesis of chitin. Despite the richness of microbial species and communities, the microbes species and the microbial community structure exhibit significant similarity between the two parasitoid wasps and between the parasitoid wasp and the host P. xylostella. Notably, the prevalence of the genus Enterococcus shared among them suggests a possible link of gut microbes between the host and their associated parasitoids. Our study offers insights into the gut microbe-based interactions between the host and parasitoid wasps for the first time, potentially paving the way for the development of an ecologically friendly biocontrol strategy against the pest P. xylostella.IMPORTANCEEndoparasitoid wasps spend the majority of their lifespan within their host and heavily rely on the host's nutrition for survival. There is limited understanding regarding the composition and physiological impacts of gut microbial communities in parasitoid wasps, particularly during the larval stage, which is directly linked to the host. Based on a thorough characterization of the gut microbe and comprehensive comparative analysis, we found the microbial species of the larval parasitoid wasp Cotesia vestalis and the pupal parasitoid wasp Diadromus collaris were similar, sharing 159 genera and 277 species, as were the microbial community structure. Certain of the dominant microbial strains of the two parasitoid wasps were similar to that of their host Plutella xylostella larvae, revealing host insect may affect the microbial community of the parasitoid wasps. The putative microbial functions associated with the parasitoid wasp larvae play an important role in dietary consumption.

Pathogens detected in ticks (Ixodes ricinus) feeding on red squirrels (Sciurus vulgaris) from city parks in Warsaw

The European red squirrel (Sciurus vulgaris) is a common host for Ixodes ricinus ticks in urban and rural habitats, however, studies on ticks and tick-borne pathogens (TBPs) of squirrels have not been conducted in Poland yet. Thus, the aims of the current study were to assess and compare the prevalence and abundance of ticks on red squirrels trapped at two sites in the Warsaw area (in an urban forest reserve and an urban park) and using molecular tools, to assess the genetic diversity of three pathogens (Borrelia burgdorferi sensu lato, Rickettsia and Babesia spp.) in I. ricinus ticks collected from squirrels. For the detection of Rickettsia spp. a 750 bp long fragment of the citrate synthase gltA gene was amplified; for B. burgdorferi s.l. 132f/905r and 220f/824r primers were used to amplify the bacterial flaB gene fragments (774 and 605 bp, respectively) and for Babesia spp., a 550 bpfragment of 18S rRNA gene was amplified. In total, 91 red squirrels were examined for ticks. There were differences in tick prevalence and mean abundance of infestation in squirrels from the urban forest reserve and urban park. Three species of B. burgdorferi s.l., Rickettsia spp., and Babesia microti were detected in ticks removed from the squirrels. Our results broaden knowledge of S. vulgaris as an important host for immature I. ricinus stages and support the hypothesis that red squirrels act as a reservoir of B. burgdorferi. Moreover, we conclude that red squirrels may also play a role in facilitating the circulation of other pathogens causing serious risk of tick-borne diseases in natural and urban areas.

Is polyphagy of a specific cryptic Bemisia tabaci species driving the high whitefly populations on cassava in eastern Africa?

AbstractSince the 1990s, the cryptic whitefly (Bemisia tabaci) has been linked to severe viral disease pandemics affecting cassava, a crucial staple crop in eastern Africa. This surge in whitefly populations has also been observed in other crops and uncultivated plants. While previous surveys have connected the increase on cassava to two specific populations, SSA1 and SSA2, the dynamics behind the population growth on other plants remain unclear. Additionally, other B. tabaci species, including EA1, IO, MED, SSA9, and SSA10, have been found on cassava in smaller numbers. This study aimed to identify the host plants that support the growth and development of different B. tabaci in Uganda by collecting fourth-instar nymphs from cassava and 20 other common host plants. Host transfer experiments were conducted to test the ability of seven species (EA1, MEAM1, MED-Africa Silver Leafing (ASL), SSA1-subgroup1, SSA1-Hoslundia, SSA6, and SSA12) to develop on cassava. The identities of the nymphs were determined using partial mitochondrial cytochrome oxidase 1 sequences. Twelve B. tabaci species were identified, including two novel species, based on the 3.5% nucleotide sequence divergence. Cassava was colonised by SSA1-SG1, SSA1-SG2, and SSA2. The most prevalent species were SSA1-SG1, MED-ASL, and SSA13, which were also the most polyphagous, colonising multiple plant species. Several whitefly species colonised specific weeds, such as Aspilia africana and Commelina benghalensis. The polyphagous nature of these species supports continuous habitats and virus reservoirs. Effective management of whitefly populations in eastern Africa requires an integrated approach that considers their polyphagy and the environmental factors sustaining host plants.

Mite composition in nests of the Japanese wood mouse, Apodemus speciosus (Rodentia: Muridae).

Acari is a diverse group of arthropods that include well-known parasites of animals. Rodents, particularly, serve as common hosts of mites and ticks, transmitting pathogens to domestic animals and humans. Understanding the ecological dynamics between parasites and rodent hosts is crucial for ecosystem management. Due to limited knowledge about the life history of ectoparasites in wild mouse nests, we collected four nests of Apodemus speciosus, the most common rodent species in the wild areas of Japan, along with soil samples near the nests to study arthropod communities. Mites overwhelmingly populated the mouse nests, comprising approximately 90% of all arthropods, while both mites and collembolans were prevalent in soil. Various species identified in our study, such as those from the families Laelapidae, Pygmephoridae, Cheyletidae, Trombiculidae, Glycyphagidae, and Thyrisomidae align with known ectoparasites or species found in the nests of other rodent species, but most parasitic species were never collected in the surrounding soil except for trombiculids. The dominance of mites in mouse nests suggests selective preference for inhabiting these host environments, although the exact reasons driving this dominance remain unclear. Further investigations into the food web within mouse nests will aid in characterising faunal composition and understanding the ecological interaction among rodents, mites, and other nest symbionts.