Previous Infestation Research Articles

Niche construction and niche choice by aphids infesting wheat ears

The niche of aphids is largely defined by their consumption of plant phloem sap and its composition, including nutrients and specialized metabolites. Niche construction is the change of the environment by organisms, which may influence the fitness of these organisms and their offspring. To better understand interactions between plants and aphids, it is necessary to investigate whether aphids modify the chemical composition of the phloem sap of their host plants and whether conspecifics are affected by previous infestation. In the current study, ears of wheat (Triticum aestivum) plants were infested with clonal lineages of the English grain aphid (Sitobion avenae) or were left uninfested. The metabolic composition of ear phloem sap exudates was analyzed through amino acid profiling and metabolic fingerprinting. Aphids of the clonal lineages were either put on previously aphid-infested or on uninfested ears and their colony sizes followed over time. Furthermore, it was investigated whether aphids choose one treatment group over another. Sitobion avenae infestation affected the relative concentrations of some metabolites in the phloem exudates of the ears. Compared to uninfested plants, the relative concentration of asparagine was higher after aphid infestation. Colonies grew significantly larger on previously aphid-infested ears, which the aphids also clearly chose in the choice experiment. The pronounced positive effect of previous infestation on aphid colonies indicates niche construction, while the choice of these constructed niches reveals niche choice by S. avenae on wheat. The interplay between these different niche realization processes highlights the complexity of interactions between aphids and their hosts.

Prevalence of pediculosis among primary school children in Tunisia

Background: Pediculus humanus capitis (head lice) infestation is a global health concern, yet no study has examined its occurrence among primary school children in Tunisia. Aim: To assess the prevalence of Pediculus capitis and its epidemiological characteristics among primary school children living in rural and urban areas of Monastir, Tunisia. Methods: We used 2-step stratified cluster sampling to randomly select 2396 children from 14 primary schools in Monastir during the 2022/2023 academic year. Head lice infestation was assessed through visual inspection of the hair, and data on the socio-demographic characteristics, lifestyle and pediculosis history of the children were collected. We used SPSS version 20 to analyse the data and used descriptive statistics to rate the frequencies. Multivariate logistic regression was used to examine the association between pediculosis and the predictor variables. Results: Overall infestation rate was 17.5% (95% CI 16.0–19.1%); infestation was 5 times higher among girls (29.1%) than boys (6.3%). Schoolchildren living in crowded family households, those in the third and fourth grades and whose parents had low education level were more exposed to infestation. Combing frequency, comb sharing and history of previous infestation had significant impact (P < 0.05) on the prevalence of pediculosis. Multivariate logistic regression showed gender and treatment outcome as the main potentiating factors. Conclusion: These findings highlight the need for pediculosis prevention and integrated health promotion programmes among primary school children and their parents, teachers and nurses in Monastir and other parts of Tunisia.

Crimean-Congo haemorrhagic fever in Iraq

Background: Pediculus humanus capitis (head lice) infestation is a global health concern, yet no study has examined its occurrence among primary school children in Tunisia. Aim: To assess the prevalence of Pediculus capitis and its epidemiological characteristics among primary school children living in rural and urban areas of Monastir, Tunisia. Methods: We used 2-step stratified cluster sampling to randomly select 2396 children from 14 primary schools in Monastir during the 2022/2023 academic year. Head lice infestation was assessed through visual inspection of the hair, and data on the socio-demographic characteristics, lifestyle and pediculosis history of the children were collected. We used SPSS version 20 to analyse the data and used descriptive statistics to rate the frequencies. Multivariate logistic regression was used to examine the association between pediculosis and the predictor variables. Results: Overall infestation rate was 17.5% (95% CI 16.0–19.1%); infestation was 5 times higher among girls (29.1%) than boys (6.3%). Schoolchildren living in crowded family households, those in the third and fourth grades and whose parents had low education level were more exposed to infestation. Combing frequency, comb sharing and history of previous infestation had significant impact (P < 0.05) on the prevalence of pediculosis. Multivariate logistic regression showed gender and treatment outcome as the main potentiating factors. Conclusion: These findings highlight the need for pediculosis prevention and integrated health promotion programmes among primary school children and their parents, teachers and nurses in Monastir and other parts of Tunisia.

Brevipalpus yothersiBaker (Tenuipalpidae) development in sweet orange plants is influenced by previous mite infestation and the presence of shelters.

Citrus leprosis is the most important viral disease affecting citrus. The disease is caused predominantly by CiLV-C and is transmitted by Brevipalpus yothersi Baker mites. This study brings some insight into the colonization of B. yothersi in citrus [(Citrus × sinensis (L.) Osbeck (Rutaceae)] previously infested by viruliferous or non-viruliferous B. yothersi. It also assesses the putative role of shelters on the behavior of B. yothersi. Expression of PR1 and PR4 genes, markers of plant defense mechanisms, were evaluated by RT-qPCR to correlate the role of the plant hormonal changes during the tri-trophic virus-mite-plant interplay. A previous infestation with either non-viruliferous and viruliferous mites positively influenced oviposition and the number of adult individuals in the resulting populations. Mite populations were higher on branches that had received a previous mite infestation than branches that did not. There was an increase in the expression of PR4, a marker gene in the jasmonic acid (JA) pathway, in the treatment with non-viruliferous mites, indicating a response from the plant to their feeding. Conversely, an induced expression of PR1, a marker gene in the salicylic acid (SA) pathway, was observed mainly in the treatment with viruliferous mites, which suggests the activation of a plant response against the pathogen. The earlier mite infestation, as well as the presence of leprosis lesions and a gypsum mixture as artificial shelters, all fostered the growth of the B. yothersi populations after the second infestation, regardless of the presence or absence of CiLV-C. Furthermore, it is suggested that B. yothersi feeding actually induces the JA pathway in plants. At the same time, the CiLV-C represses the JA pathway and induces the SA pathway, which benefits the mite vector.

Previous infestation by conspecifics leads to a transient increase of the performance of Sitobion avenae aphids on wheat leaves

Abstract The ecological niche of aphids is largely defined by the phloem sap of plants, which they consume. Previous studies revealed that aphids may change the phloem sap metabolome and that a previous aphid infestation may benefit them. As aphids reproduce parthenogenetically, the performance and preference of aphids of the same monoclonal aphid lineage can be compared between previously uninfested and previously aphid‐infested plants. Wheat (Triticum aestivum) leaves were infested by clonal lineages of Sitobion avenae aphids for 9–10 days. Leaf phloem exudates were analysed using amino acid profiling and metabolic fingerprinting, capturing mainly specialised metabolites. It was investigated whether aphid colony sizes differ between leaves that were previously uninfested or infested by aphids of a different clonal lineage or by aphids of the same clonal lineage and whether aphids show a preference for any of these leaves. The relative concentrations of metabolites in the phloem exudates were not affected by aphid infestation. Aphid colonies were partly larger on previously aphid‐infested leaves than on control leaves. However, this effect was transient and finally colonies had similar sizes. Given a choice between previously aphid‐infested and uninfested leaves, S. avenae nymphs showed no preferences. The findings that positive effects of previous aphid infestation on aphid performance are transient and that the performance but not the preference of the aphids was affected by previous aphid infestation highlight the temporal dynamics and complexity of aphid–plant interactions. Niche alteration processes may be partly involved in these interactions.

More than trichomes and acylsugars: the role of jasmonic acid as mediator of aphid resistance in tomato

ABSTRACT This study investigates the impact of priming on the resistance of tomato plants to the potato aphid Macrosiphum euphorbiae, focusing on the role of glandular trichomes. Glandular trichomes are specific hairs that provide protection to tomato plants against herbivorous insects. The experimental priming conducted in this study revealed that prior infestation by Spodoptera littoralis caterpillars increased the plant's resistance against M. euphorbiae, pointing at the jasmonic acid (JA) signaling pathway in regulating this plant-aphid interaction. Glandular trichomes type IV were effective against aphids regardless of the previous infestation. Using JA-deficient tomato (spr2), we observed that M. euphorbiae multiplication increased, while the number of aphids on salicylic -deficient NahG plants was lower than in the wildtype Moneymaker. These findings emphasize the crucial role of the JA signaling pathway in tomato plant resistance to aphids and the importance of glandular trichomes to enhance plant defences against pests.

Different triggers, different stories: Bark-beetle infestation patterns after storm and drought-induced outbreaks

In the recent decades, Norway spruce forests (Picea abiesKarst.) in Europe have been subject to large-scale tree mortality caused by the spruce bark beetle (Ips typographusL.). The outbreaks were induced by storm-felling events and periods of drought, which are becoming increasingly frequent due to climate change. Because storms and droughts spatially affect forests differently, the infestation patterns and configuration of the bark beetles might differ between storms and drought. In this study, we examined local and landscape factors associated with bark beetle-caused tree mortality after one storm (2005) and one drought-induced spruce bark beetle outbreak (2018), both occurring in southern Sweden. A total of 13,192 infested one-ha pixels after the storm and 6,425 one-ha pixels after the drought (in total 19,617) were compared regarding differences in infestation occurrence and size and associated forest structures and climate between the two different outbreaks, using a generalized linear model (GLM) approach. Based on our findings, we discovered that the allocation of infestation patch sizes (including four classes: 5–10, 11–25, 26–50 and >50 infested trees) for the two outbreaks were quite similar with a large proportion (>0.6) of small groups (≤10 trees).However, the outcomes from this study demonstrate that the drivers behind the spatial configuration of bark beetle infestations can differ considerably between outbreaks triggered by storms and droughts, and the main cause seems to be linked to the spatial distribution of susceptible trees. The most consistent differences for both occurrence and infestation size were that storm-induced infestations increased more with spruce volumes and area of protected forests (nature reserves) in the landscape; whereas for the drought-induced infestations, occurrence and size increased more with clear-cuts in the landscape and spruce heights across spatial scales. Soil moisture and mean drought index (SPEI; May-July) were important for both outbreaks, but generally more important for the infestation sizes after droughts than after storms and may involve a time-lagged effect.The reasoning behind the differences between storms and droughts may be that during storm-induced outbreaks, when the wind-felled trees are removed or not suitable anymore, bark beetles need to find specific susceptible standing trees, while after drought all trees are more or less stressed, which results in a selection of large trees in dry and warm landscapes as they have more resources and favorable reproduction conditions. Finally, we show that the previous infestation size influenced the later infestation size negatively within landscapes of 25 ha and this seems to be related to depletion of susceptible host trees.These results are important for the assessment of more specific outbreak predictions, which should be integrated in future risk mapping of bark beetle outbreaks.

Multifunctionality of Jasmonic Acid Accumulation during Aphid Infestation in Altering the Plant Physiological Traits That Suppress the Plant Defenses in Wheat Cultivar XN979.

Crop plants have coevolved phytohormone-mediated defenses to combat and/or repel their colonizers. The present study determined the effects of jasmonic acid (JA) accumulation during aphid infestation on the preference and performance of Sitobion miscanthi Takahashi (Hemiptera: Aphididae), and its potential role in fine-tuning hormone-dependent responses in XN979 wheat cultivar seedlings was evaluated via the transcriptional profiles of marker genes related to JA- and salicylic acid (SA)-dependent responses. The preference experiment and the life table data reveal that direct foliage spraying of 2.5 mM methyl jasmonate (MeJA) exhibited weak negative or positive effects on the preferential selection and the population dynamics and oviposition parameters of S. miscanthi. The transcription level of phytohormone biosynthesis genes shows that foliage spraying of MeJA significantly upregulated the marker genes in the JA biosynthesis pathway while downregulating the SA pathway. In addition, either MeJA treatment or previous aphid infestation significantly induced upregulated transcription of the genes involved in the JA- and SA-dependent defense responses, and the transcription level of the tryptophan decarboxylase (TaTDC) gene, which facilitates the conversion of L-tryptophan to tryptamine, was rapidly upregulated after the treatments as well. The main products of tryptamine conversion could play a crucial role in suppressing SA-dependent defense responses. These results will provide more experimental evidence to enable understanding of the antagonistic interaction between hormone signaling processes in cereals under aphid infestation.

Ticks Infesting Dogs in Khyber Pakhtunkhwa, Pakistan: Detailed Epidemiological and Molecular Report.

Ticks and tick-borne diseases are considered a major challenge for human and animal health in tropical, sub-tropical, and temperate regions of the world. However, only scarce information is available on the characterization of tick species infesting dogs in Pakistan. In this study, we present a comprehensive report on the epidemiological and phylogenetic aspects of ticks infesting dogs in Pakistan using the mitochondrial markers i.e. Cytochrome c oxidase subunit 1 (cox1) and 16S ribosomal RNA (16S rRNA) nucleotide sequences. A total of 300 dogs were examined and 1150 ixodid ticks were collected across central Khyber Pakhtunkhwa, Pakistan. The morpho-molecular characterization of hard ticks revealed the presence of two ixodid tick genera on dogs, i.e., Hyalomma and Rhipicephalus, including six tick species viz. Hyalomma dromedarii (15.9%), Hyalomma excavatum (3%), Rhipicephalus sanguineus s.l. (41.3%), Rhipicephalus turanicus s.s. (28.7%), Rhipicephalus haemaphysaloides (10.2%), and Rhipicephalus microplus (2%). The total prevalence of tick infestation in dogs was 61%. The district with the highest tick prevalence rate in dogs was Mardan (14.7%), followed by Peshawar (13%), Swabi (12%), Charsadda (11%), and Malakand (10.3%), respectively. Risk factors analysis indicated that some demographic and host management-associated factors such as host age, breed, exposure to acaricides treatment, and previous tick infestation history were associated with a higher risk of tick infestation on dogs. This is the first molecular report confirming the infestation of Hyalomma and Rhipicephalus tick species in the dog population from the study area. The present study also reported a new tick−host association between Hy. excavatum, Hy. dromedarii, and dogs. Phylogenetic analysis revealed that cox1 partial nucleotide sequences of Hy. excavatum in our dataset were 100% identical to similar tick specimens identified in Turkey, and those of Hy. dromedarii were identical to tick specimens from Iran. Whereas, Rh. haemaphysaloides and Rh. microplus’ cox1 partial nucleotide sequences were identical to sequences previously published from Pakistan. Rhipicephalus turanicus s.s. ‘s cox1 isolates from the present study were 99.8−100% identical to Pakistani-reported isolates, and those of Rh. sanguineus s.l. were 100% identical to Chinese specimens. Results on the genetic characterization of ticks were further confirmed by 16S rRNA partial nucleotide sequences analysis, which revealed 100% identity between the tick isolates of this study and those of Hy. excavatum reported from Turkey; Hy. dromedarii specimens reported from Senegal; Rh. haemaphysaloides, Rh. microplus, and Rh. turanicus s.s., previously published from Pakistan, and Rh. sanguineus s.l., published from China. Furthermore, phylogenetic analysis showed that the Rh. sanguineus s.l. isolates of this study clustered with specimens of the tropical lineage with 7.7−10% nucleotide divergence from the specimens of the temperate lineage. Further molecular works need to be performed throughout Pakistan to present a more detailed map of tick distribution with information about dog host associations, biological characteristics, and pathogen competence.

First report of Pepo aphid‐borne yellows virus on courgette in Italy

During monitoring for cucurbit viruses in greenhouses in the municipalities of Torre del Greco (Napoli province, Campania) and Aversana (Salerno province, Campania) in September 2019 and October 2022, respectively, samples of commercial hybrids of courgette (Cucurbita pepo) showing symptoms of leaf yellowing and mosaics (Figure 1) were collected and stored as dried material. Three samples from 2019 and two samples from 2022, were inoculated mechanically onto courgette. Within two weeks, typical symptoms of Tomato leaf curl New Delhi virus (ToLCNDV), consisting of leaf crumpling, yellowing and downward curling, were observed. ToLCNDV infection was confirmed by DAS-ELISA (Bioreba, Switzerland). This is not a new record for Campania since ToLCNDV was detected in courgette in 2016 and causes a serious disease problem for cucurbit crops in this region. The samples were also checked for polerovirus infection by RT-PCR as follows. Total RNA was extracted from infected tissues using TRI-reagent (Sigma-Aldrich, USA) and RT-PCR was performed with polerovirus primers Pol-G-F and Pol-G-R (Knierim et al., 2014). A 1.1 Kb fragment was obtained from two samples, one sampled in 2019 and the other in 2022. These amplicons were sent to Genoscreen (Lille, France) for direct sequencing. The sequences obtained (GenBank Accession Nos. OP156930 and OP973153, respectively), encompassing part of the polerovirus RNA-dependent RNA polymerase, intergenic region, coat protein and movement protein, shared a close relationship with Pepo aphid-borne yellows virus (PABYV) isolates from different origins. PABYV was first described in 2008 in Mali (Knierim et al., 2014), then in South Africa (Ibaba et al., 2015), Côte d'Ivoire (Kone et al., 2015), in Tanzania and Mayotte (Desbiez et al., 2016), and a polerovirus closely related to PABYV, named “pumpkin polerovirus” was described more recently in Kenya (Kidanemariam et al., 2019). In the Mediterranean area, PABYV has been detected in Syria in 2009 and in Greece in 2016 (Lotos et al., 2016). The two sequences of the Italian PABYV isolates (IT-236-19 and IT-22, respectively) were 99.2% identical and shared 98.4% identity with the isolate AE142 (LN865082),reported in Greece in 2016 (Lotos et al., 2016), and 98.3% with isolate W-8-1-Sy-09 (KC960436) reported in Syria in 2009. These four isolates formed a distinct group in a phylogenetic reconstruction (Figure 2), suggesting a common origin for the PABYV isolates spreading in the Mediterranean area. PABYV belongs to the polerovirus genus which are phloem-restricted RNA plant viruses transmitted by aphids. Nevertheless, Bemisia tabaci has been reported recently to transmit a new species of polerovirus, Pepper whitefly borne vein yellows virus, in pepper in Israel, as well as a recombinant strain of Cucurbit aphid-borne yellows virus in cucurbits in Brazil. In our case, no aphids were observed during sampling (although previous infestation could not be excluded) but abundant colonies of B. tabaci were recorded. The possibility of PABYV transmission by B. tabaci requires investigation. This is the first report of PABYV in Italy. The finding of PABYV in a new geographic area represents further evidence of the active and current spread of the virus, suggesting the need for more extensive sampling of cucurbit crops and the identification of vectors and alternate hosts to better understand the epidemiology of cucurbit-infecting poleroviruses in the Mediterranean and in Africa. This work was carried out as part of the Short Term Mobility (STM) 2020 programme financed by the National Research Council (CNR) of Italy.

Epidemiological Study of Pediculosis among Primary School Children in Sulaimani Governorate, Kurdistan Region of Iraq.

Pediculosis is a common parasitic public health issue. Many socio-demographic and economic factors affect the pattern and prevalence of pediculosis. It is widely spread among pupils, particularly those in elementary schools. This study aimed to determine the prevalence of Pediculus capitis infestation and its related risk factors in primary school children in Sulaimani Governorate, Kurdistan Region of Iraq. This is a cross-sectional study, overall, 2064 primary school children (aged 5-14 years) during the period from October 2019 to February 2020 were randomly examined for the presence of any stage of Pediculosis capitis in both urban and suburban areas. The schools were selected by multistage sampling methods. A questionnaire was sent to the parents to get consent and fill in for every single pupil. The results were computed using the chi-square test and logistic regression analysis. The overall prevalence of head lice infestation was (9.16%). The study found a significant association of Pediculosis capitis infestation with gender, parents' education level, mother's employment, number of siblings, and previous infestation. The older age of children (≥12 years old) and the higher-grade pupils (4th to 6th class) were more infested. Head lice remain a health problem for school children. It needs collaboration of many sectors for decreasing and early detection and treatment in both urban and suburban areas since they have a close rate of infestation.

Prevalence of Pediculus humanus capitis and associated risk factors among elementary school-aged girls in Paveh, West Iran.

Head lice infestation is considered as a common dermatological health problem worldwide. This study was aimed to determine the pediculosis prevalence and associated risk factors among school-aged girls enrolled in public elementary schools of the city of Pave, Kermanshah province, West Iran. The study findings will provide an evidence base, upon which a multifaceted intervention against pediculosis can be formulated and implemented. In this cross-sectional study, 361 elementary school-aged girls were recruited from October to December 2018 at the beginning of the school year. Diagnosis was made by visual inspection. A structured questionnaire was utilized to collect data about past history of infestation and associated factors. A total of 26/361 (7.2%; 95% CI: 4.50-9.90) suffered from pediculosis. Pediculosis was associated with the history of previous infestation (OR: 6.12; 95% CI: 2.68-13.99; p < 0.001), low frequency of bathing (OR: 7.90; 95% CI: 3.36-18.60; p < 0.001), low frequency of hair combing (OR: 3.64; 95% CI: 1.56-8.50; p = 0.004), screening of the student's hair by parents at home (OR: 0.39; 95% CI: 0.19-0.78; p < 0.001) and with the absence of screening by the school health officer in the schools (OR: 7.16; 95% CI: 2.91-17.61; p < 0.001). Synchronized efforts to enhance public knowledge, periodic examination of school-aged children for pediculosis, and proper treatment of infested patients are needed to control the disease in the Iranian elementary schools. The applied strategies in low and middle income countries is suggested to be focused mainly on low cost family-based and school-based initiatives for maximum effectiveness.

Damage of brown planthopper (BPH) Nilaparvata lugens and rice leaf folder (LF) Cnaphalocrocis medinalis in parent plants lead to distinct resistance in ratoon rice

ABSTRACT Herbivore-induced defense responses are often specific, whereas plants could induce distinct defense responses corresponding to infestation by different herbivorous insects. Brown plant hopper (BPH) Nilaparvata lugens, a phloem-feeding insect, and rice leaf folder (LF) Cnaphalocrocis medinalis, a chewing insect, are both specialist herbivores on rice. To characterize the distinct resistance primed by prior damage to these two specialist herbivores, we challenged rice plants with two herbivores during vegetative growth of parent plants and assessed plant resistance in subsequent ratoons. Here, we show that LF and BPH induce different suites of defense responses in parent rice plants, LF induced higher level of JA accumulation and OsAOS, OsCOI1 transcripts, while BPH induced higher accumulation of SA and OsPAL1 transcripts. Moreover, an apparent loss of LF resistance was observed in OsAOS, OsCOI1 RNAi lines. Ratoon plants generated from parents receiving prior LF infestation exhibited higher jasmonic acid (JA) levels and elevated levels of transcripts of defense-related genes associated with JA signaling, while ratoon generated from parents receiving prior BPH infestation exhibited higher salicylic acid (SA) levels and elevated levels of transcripts of defense-related genes associated with SA signaling. Moreover, previous LF infestation obviously elevated ratoons resistance to LF, while previous infestation by BPH led to enhanced resistance in ratoons to BPH. Pre-priming of ratoons defense to LF was significantly reduced in OsAOS and OsCOI1 RNAi plant, but silencing OsAOS and OsCOI1 did not attenuate ratoons resistance to BPH. These results suggest that infestation of two specialist herbivores with different feeding styles in parent crop led to distinct defense responses in subsequent rations, and the acquired resistance to LF in ratoons is associated with priming of jasmonic acid-dependent defense responses.

Molecular evidence, risk factors analysis, and hematological alterations associated with Theileria spp. spillover in captive wild mouflon sheep in Punjab, Pakistan.

Landscape anthropization and interaction between domestic and wild animals are the major contributing factors involved in the emergence of new pathogens in wild animals. Theileriosis is an emerging issue of wild ungulates, especially in the tropical and subtropical areas of the globe. The current study investigated the mouflon sheep for Theileria infection using molecular methods and hematological analysis. This study was conducted on a total of 103 captive wild mouflon sheep present in eight different recreational zoos, and wildlife parks in Punjab, Pakistan to investigate the genotypic prevalence of Theileria spp. by targeting 18S rRNA and molecular evidence for Theileria spillover between domestic and wild mouflon sheep by phylogenetic analysis. The association of assumed risk factors and the effect of Theileria spp. on various hematological parameters were also assessed. The results depicted that Theileria spp. was prevalent in 8 (7.77%, CI 95%: 3.99-14.59%), and 11 (10.68%, CI 95%: 06.07-18.12%) animals based on microscopy, and PCR, respectively. The phylogenetic analysis of the 18S rRNA gene of Theileria spp. from mouflon revealed a close resemblance with T. annulata from domestic animals. The risk factor analysis revealed that tick infestation, enclosure hygiene, previous tick infestation history, and the presence of wooden logs in the enclosure were significantly (P<0.05) associated with the occurrence of Theileria spp. infection in the captive mouflon sheep of Pakistan. Furthermore, a significant reduction in blood parameters like PCV, RBCs count, Hb, and platelets was observed in Theileria-positive animals. This study is the first evidence at the molecular level to characterize the spillover of Theileria spp. between the captive wild mouflon sheep and domestic animals of Pakistan, and it will be useful in developing control strategies for emerging theileriosis in captive wild animals.

Prevalence of Head Lice Infestation and its Associated Factors Among Female Primary School Students in Ghahavand County and Compared with the Previous Studies

Background and Objectives: Despite the progress of communities’ health, head lice (Pediculus capitis) infestation remains a major health problem. The aim of the study was to investigate the prevalence of head lice infestation and its associated factors among female primary school students in Ghahavand County and compare with the previous studies. Methods: The students were cross-sectionally examined and pediculosis infected students were identified. The student demographic information was collected and recorded. The results were analyzed by Chi-square test of SPSS software. Significance level was considered P&lt;0.05. Results: Among 499 students participating in the study, 89 students (17.8%) had pediculosis. There was a significant difference between student pediculosis prevalence in terms of parents’ educational level, previous infestation history, parental assistance in health affairs, number of household members, and condition, type and length of students’ hair (P&lt;0.05) But there was not a significant difference between student pediculosis prevalence in terms of student educational level, father’s employment, weekly bathing, and the use of personal brush (P&gt;0.05). The results compared with the previous studies. Conclusion: Head lice infestation is relatively high in students that depends on factors such as parent educational levels, previous infestation history, parental assistance in health care, number of household members, and the condition, type and length of the students’ hair. It is recommended to treat the pediculosis infected students along with attention to the instructions and training of parents and school health instructors.

Prevalence of and risk factors for Enterobius vermicularis infestation in preschool children, West Bank, Palestine, 2015.

Enterobius vermicularis (pinworm) infestation is a common condition that primarily affects children. The aim of this study was to assess the prevalence of and the risk factors for E. vermicularis infestation in preschool children in north West Bank. A cross-sectional study that included the six main governorates in north West Bank was carried out on a sample of 384 preschool children from 86 day-care centres. The perianal cellophane tape method was used to detect E. vermicularis infestation. Parents/guardians of participating children completed a questionnaire to collect information about: demographic characteristics; hygiene behaviour; socioeconomic status; history of previous infestation; and presence of symptoms. Risk factors for infestation were assessed using logistic regression analysis. Of the 384 children, 85 (22.1%) had E. vermicularis infestation. Age (P = 0.04), governorate (P = 0.01), residency (P = 0.03), number of household members (P < 0.001) and washing hands after toilet use (P = 0.01) were significantly associated with E. vermicularis infestation. In the logistic regression analysis, factors that increased the probability of infection were: living in villages (odds ratio (OR) 2.25; 95% confidence interval (CI): 1.01-5.00), living in a household with ≥ nine family members (OR 3.63; 95% CI: 1.42-9.26) and not washing hands after using the toilet (OR 2.4; 95% CI: 1.30-4.40). E. vermicularis is an important helminthic infestation among preschool children in Palestine. Efforts are needed to ensure the availability of treatment for infected children at primary care centres and to reinforce hygiene behaviour.

Maize resistance to Spodoptera frugiperda and its relationship to landrace variety, plant stage, and larval origin

AbstractPrevious studies have raised the hypothesis that laboratory‐reared insects may lose their ability to induce plant defenses because induction‐associated gut bacteria may be eliminated by antibiotics used in artificial diets. The present study was conducted to determine whether maize (Zea mays L., Poaceae) responses to Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) differ when field‐collected vs. laboratory‐reared insects are feeding. One fifth instar from the laboratory or field was released onto a resistant or a susceptible landrace variety at vegetative stages 4 and 6 (V4 and V6), or plants remained uninfested. Five days later, damage was estimated and sections of maize leaves were fed to forth instars in a Petri dish assay to assess the effects of previous feeding on weight gain, leaf consumption, and nutritional indices of conspecifics. Initially, field‐collected larvae caused more damage on V4, but not on V6 maize plants, than laboratory‐reared larvae. In V6 plants, the resistant variety showed less leaf damage than the susceptible variety. In a Petri dish assay, there were no differences between effects of laboratory‐reared and field‐collected larvae on the measured parameters, but larvae from both sources promoted increased susceptibility in maize plants at the V4, but not the V6 stage. This was characterized by higher weight gain and higher efficiency of conversion of ingested food (ECI) (on both maize varieties), and lower metabolic cost (MC) (on one variety) when S. frugiperda larvae fed on leaves pre‐infested with laboratory‐reared larvae compared to leaves of uninfested plants. Conversely, S. frugiperda larvae fed on leaves pre‐infested with field‐collected larvae consumed a greater amount of leaf tissue (on both varieties) compared to leaves of uninfested plants. A similar experiment with neonates showed no effects of landrace variety or previous infestation on insect weight and survival, but insects obtained a higher body weight when fed on V4 compared to V6 plants. In conclusion, S. frugiperda laboratory‐reared larvae were equally able as field‐collected larvae to induce susceptibility in V4 maize plants, and maize plants were more resistant to the pest at the V6 than at the V4 stage.

Foliar Aphid Herbivory Alters the Tomato Rhizosphere Microbiome, but Initial Soil Community Determines the Legacy Effects

Aboveground herbivory can impact the root-associated microbiome, while simultaneously different soil microbial communities influence herbivore performance. It is currently unclear how these reciprocal top-down and bottom-up interactions between plants, insects and microbes vary across different soils and over successive plant generations. In this study, we examined top-down impacts of above-ground herbivory on the rhizosphere microbiome across different soils, assessed bottom-up impacts of soil microbial community variation on herbivore performance, and evaluated their respective contributions to soil legacy effects on herbivore performance. We used Macrosiphum euphorbiae (potato aphid) and Solanum pimpinellifolium (wild tomato) to capture pre-domestication microbiome interactions with a specialist pest. First, using 16S rRNA sequencing we compared bacterial communities associated with rhizospheres of aphid-infested and uninfested control plants grown in three different soils over three time points. High aphid infestation impacted rhizosphere bacterial diversity in a soil-dependent manner, ranging from a 22% decrease to a 21% increase relative to uninfested plants and explained 6–7% of community composition differences in two of three soils. We next investigated bottom-up and soil legacy effects of aphid herbivory by growing wild tomatoes in each of the three soils and a sterilized “no microbiome” soil, infesting with aphids (phase one), then planting a second generation (phase two) of plants in the soil conditioned with aphid-infested or uninfested control plants. In the first phase, aphid performance varied across plants grown in different soil sources, ranging from a 20 to 50% increase in aphid performance compared to the “no microbiome” control soil, demonstrating a bottom-up role for soil microbial community. In the second phase, initial soil community, but not previous aphid infestation, impacted aphid performance on plants. Thus, while herbivory altered the rhizosphere microbiome in a soil community-dependent manner, the bottom-up interaction between the microbial community and the plant, not top-down effects of prior herbivore infestation, affected herbivore performance in the following plant generation. These findings suggest that the bottom-up effects of the soil microbial community play an overriding role in herbivore performance in both current and future plant generations and thus are an important target for sustainable control of herbivory in agroecosystems.

Seasonal and spatial patterns of mudblister worm Polydora websteri infestation of farmed oysters in the northern Gulf of Mexico

Mudblister worms Polydora websteri bore holes into oyster shells, and oysters respond by secreting extra layers of shell, creating a mudblister. When shucked, mudblisters can burst and release anoxic mud. Thus, infestation devalues oysters, particularly on the half-shell market. This study quantified oyster condition index and worm abundances over 2 full growing seasons at commercial oyster farms on the US Gulf of Mexico coast, and our results indicate that oyster growth rate, manipulated through ploidy and stocking densities, had little effect on worm infestation. Larval spionid worms were found year-round. Larval abundances were slightly higher within than away from farms, and larval size distributions were skewed toward smaller larvae within the farms, suggesting that farms may be a source of larvae. Triploid oysters had higher or comparable condition index values to diploids, but during summer months, when worm infestation was high, worm infestation was not correlated with condition index. Previously infested shells deployed at farms became more infested than uninfested shells at moderate infestation levels, but re-infestation was influenced more by farm location than by previous infestation condition. Higher infestation at a farm with more variable salinity as well as higher infestation in 2017 when salinity was lower suggest that salinity may be a potential driver of mudblister worm infestation. Results indicate that oyster farmers on this coast should use desiccation to treat oysters for mudblister worms frequently during the summer, but that manipulating stocking density or ploidy is unlikely to be effective in preventing mudblister worm infestation.

Infestation of fruit by conspecific and heterospecific females deters oviposition in two Tephritidae fruit fly species

AbstractTephritidae fruit fly larvae develop entirely in the host chosen by the females. To improve the fitness of their progeny, females would benefit from rejecting previously exploited hosts. Anastrepha fraterculus and Ceratitis capitata are two species of fruit flies having similar nutritional requirements and overlapping in their distribution. Previous studies found that competition between the larvae of these species might reach high levels, suggesting that cross‐recognition would be an adaptive trait. In this work, we tested the ability of A. fraterculus and C. capitata females to recognize and avoid fruits previously infested by both conspecific and heterospecific females. In laboratory behavioural arenas, females were presented with fruits that had been previously exposed to either conspecific or heterospecific females. Then, we conducted choice and non‐choice assays to compare the response of A. fraterculus and C. capitata females to infested and non‐infested fruits. In non‐choice tests, the females from both species rejected fruits previously infested by conspecific and heterospecific individuals. However, the rejection occurred at different steps of the sequence leading to oviposition: A. fraterculus showed a lower rate of visits to infested fruits, whereas C. capitata visited both infested and non‐infested fruits, but the latency to visit a fruit and the rejection frequency were higher and the duration of the visit to infested fruit was lower. In choice assays, the rejection of heterospecific infested fruit was higher than that of conspecific infested fruits, for both species. Our results suggest that, regardless of the sensory mechanism used by females, the recognition of previous infestation is bidirectional and females of both species, belonging to different genera, recognize fruit infested by heterospecifics. These responses indicate that cross‐recognition, supposedly a highly beneficial trait, could be occurring in nature, thus reducing interspecific competition and contributing to the coexistence of these species.