Search Results (81)

Background: Scrub typhus (ST) is caused by Orientia tsutsugamushi (OT) infection, which is transmitted to humans through the bites of infected chiggers. The clinical presentations range from mild to life-threatening multi-organ dysfunction. This report describes a cluster of ST cases involving five oil palm estate workers in Pekan district, Pahang, Malaysia. Methods: The clinical history, laboratory, and entomological investigation were conducted on the patients, including the index case and four suspected cases in the cluster. Polymerase chain reaction (PCR) tests for OT and genotyping were performed on the patients’ blood and urine samples. Serological testing by indirect immunoperoxidase (IIP) test against Rickettsial diseases was also conducted. Principal Findings: Patients presented with fever, myalgia, headache, rash, cough, and eschar. The index case developed severe ST complicated by acute kidney injury (AKI) and respiratory distress, requiring intubation and ventilation at the intensive care unit of a tertiary hospital. ST was confirmed through PCR analysis of a urine sample, showcasing a novel diagnostic approach. The other four cases were confirmed by a four-fold rise in immunoglobulin G (IgG) antibody titers. Conclusions: oil palm estate workers are at high risk for chigger exposure in Malaysia. Awareness among clinicians and the public of ST is crucial for effective prevention, accurate diagnosis, and optimal management. Full article

Background/Objectives: Toxocara spp. infection has been associated with severe asthma and allergic manifestations due to the activation of eosinophils by the release of Th2 cell cytokines. The aim of this study was to investigate the association between Toxocara spp. infection and eosinophil levels in severe asthmatic patients. Methods: The socio-demographic, peripheral blood eosinophils counting total IgE, sIgE to aeroallergens and FEV1 results were acquired from the Program of Asthma and Rhinitis Control (ProAR) at the Salvador–Brazil databank; IgG anti-Toxocara spp. levels were measured in 176 severely asthmatic patients by indirect ELISA. Results: The Toxocara spp. seroprevalence was 50.6%. Eosinophilia was present in 54% of the population. The correlation between IgG anti-Toxocara spp. levels and eosinophils levels was positive. Eosinophilic individuals with SPT, sIgE for D. pteronyssinus, D. farinae and B. tropicalis showed positive results; IgE ≥ 160 UI/dL and uncontrolled asthma presented more positive results for IgG anti-Toxocara spp. Conclusions: Our findings suggest that eosinophil levels are influenced by the presence of IgG antibodies against Toxocara spp. Additionally, helminth infection may modulate immunological responses in allergies and uncontrolled asthma, which could help explain the exacerbation of asthma symptoms. Full article

Urochloa ruziziensis (R. Germ. and C.M. Evrard) Crins (synonym Brachiaria ruziziensis) Poales: Poaceae) pastures are often attacked by spittlebugs, compromising their biomass for livestock usage. A sustainable control method involves the use of entomopathogenic fungi. Therefore, the objective of this study was to evaluate the efficacy of controlling Mahanarva spectabilis Distant, 1909 (Hemiptera: Cercopidae), in greenhouse and field conditions via endophytic entomopathogenic fungi. In the greenhouse, the mortality of nymphs and adults was 100%, and more than 53% of the nymphs and 59% of the adults that fed on plants inoculated with Fusarium multiceps and Metarhizium anisopliae presented with these fungi in their cadavers. In the field, more than 45% of the insect cadavers that had fed on plants grown from fungus-treated seeds were found to contain the fungi. F. multiceps was found to be endophytic in more than 60% of the plants up to 90 days after seed treatment, and M. anisopliae was found in more than 70% of the plants up to 120 days after treatment. The damage scores of the control plants, both in the greenhouse and in the field, were greater than those of the plants inoculated with the fungi. F. multiceps and M. anisopliae in the endophytic pathway of U. ruziziensis are therefore efficient at controlling spittlebugs. Full article

The red spider mite, Tetranychus macfarlanei, is a significant pest of various crops, and silicon (Si), a beneficial micronutrient, serves as a physical defense against herbivores when accumulated in plant tissues. This study examined the effects of silicon on the biology of T. macfarlanei on Lablab purpureus plants treated with 0 ppm (control), 28, and 56 ppm silicon concentrations. The results showed that silicon treatments notably affected mite development. At the highest concentration of 56 ppm Si, females exhibited the longest immature period, shortest lifespan, and shortest oviposition period. Egg production per female was highest at the 0 ppm Si level (94.62) and lowest at the 56 ppm Si concentration (42.29). Life table parameters, including the intrinsic rate of increase (r), net reproductive rate (R₀), finite rate of increase (λ), and gross reproductive rate (GRR), declined progressively with increasing silicon concentrations. Compared to the control (0 ppm Si), the highest silicon level resulted in reductions of approximately 24% in r, 55% in R₀, 4% in λ, and 27% in GRR, indicating a substantial negative impact of silicon on the reproductive potential of T. macfarlanei. These findings suggest that higher silicon levels effectively suppress T. macfarlanei populations and may be useful in integrated mite management strategies. Full article

Rickettsiae are Gram-negative and obligate intracellular bacteria that cause rickettsioses. These pathogens are typically transmitted by arthropod vectors, such as ticks, mesostigmatid mites, and fleas. Rickettsiae are responsible for many emerging infectious diseases worldwide and are the second most frequently reported cause of non-malarial febrile illnesses in Southeast Asia. However, in Malaysia, studies on the prevalence and distribution of rickettsiae have primarily focused on humans, with limited data on these bacteria in vectors and small mammal hosts. Thus, this study aims to investigate the presence of Rickettsia spp. in small mammals and their associated mesostigmatid mites collected from potential rickettsioses areas in Selangor. Animal trapping was conducted across three different ecological study sites comprising a recreational area, agricultural land, and coastal area. A total of 41 small mammals and 363 mesostigmatid mites were collected and identified. Ten percent of the total individual mites were processed for morphological examination, and the remaining mites were then pooled by hosts, with five individual mites per tube, for DNA extraction. The collected samples, comprising blood, animal tissue, and pooled mites, were subjected to DNA extraction and were screened for Rickettsia spp. via nested polymerase chain reaction (PCR), targeting the citrate synthase-encoding gene (gltA) and outer membrane protein B gene (ompB). Interestingly, two pools (3.33%) of Laelaps spp. recovered from Maxomys whiteheadi and Bandicota indica, collected from a recreational area, tested positive for Rickettsia spp. Sequence analysis and phylogenetic tree of the ompB gene revealed the presence of Rickettsia felis in both laelapid mite pools. To our knowledge, this study provides the first molecular detection of R. felis in Laelaps spp. in Malaysia. Full article

This study investigated the lethal and transgenerational effects of botanical and synthetic insecticides on the egg parasitoid Trichogramma atopovirilia, an important natural enemy of Spodoptera frugiperda in Brazil and beyond. The treatments were assessed for their impact on parasitism, emergence, sex ratio, and flight capacity of adults exposed to contaminated eggs. The botanical insecticide ESAM (ethanolic seed extract of Annona mucosa) significantly reduced the parasitism in the F₀ generation by 99.76%, categorizing it as toxic. Anosom^® [acetogenins (annonin as a major component)] and Azamax^® [limonoids (azadirachtin + 3-tigloilazadirachtol)] also caused substantial reductions (99.13% and 92.36%, respectively) in the parasitism rate. EFAMON (ethanolic leaf extract of Annona montana) reduced the parasitism by 62%, while the synthetic insecticide Premio^® (chlorantraniliprole) resulted in a 28.21% reduction. In the F₁ generation, emergence rates for EFAMON, Azamax^®, and Premio^® exceeded 70%, showing no significant differences from the negative control (82%), while Anosom^® resulted in a lower emergence rate of 61.39%. No significant effects were observed on sex ratio or parasitism in the F₁ and F₂ generations. Most adults reached high flight capacity (above 80%). These results indicate that while ESAM was toxic, the other treatments showed no transgenerational effects. Our findings contribute to understanding insecticide selectivity and highlight the importance of such studies for the sustainable management of S. frugiperda within integrated pest management programs. Full article

Phytophagous mites are herbivores that feed on various economically important plants, such as soybean [Glycine max (L.) Merril]. Thus, our objective is to evaluate the oxidative stress stage of soybean plants infested by Tetranychus ludeni Zacher. Leaflets from three trifoliate leaves were pooled to form composite samples for each exposure time and evaluated at the following evaluation times: 0 h, 20 min, 6 h, 12 h, 24 h, and 48 h. In the initial phase of infestation (20 min), an oxidative burst was observed, represented by prominent hydrogen peroxide accumulation rather than superoxide radicals. This oxidative burst occurred in parallel to a strong increase in the antioxidant activities of catalase, ascorbate peroxidase, and glutathione S-transferase, but not in that of superoxide dismutase. These changes likely reflected an enhanced activation of signaling pathways involved in the oxidative stress response. After this initial phase, from 20 min to 6 h, a prominent decrease occurred in catalase, ascorbate peroxidase, and glutathione S-transferases activities, despite the hydrogen peroxide levels remaining significantly elevated, along with a marked but transient increase in the reduced glutathione content and proline. Interestingly, superoxide dismutase activity increased significantly after 6 h in parallel to lipid peroxidation, whereas the content of hydrogen peroxide remained elevated until 12 h of infestation. By the final evaluation, after 48 h of infestation, some redox indicators remained altered in relation to control plants, but in a state of moderate redox stress. Thus, in an unprecedented way, our data suggest that T. ludeni infestation triggered a moderate oxidative stress response in soybean plants. These findings highlight that proper monitoring and management can reduce economic losses without resorting to aggressive chemical interventions. Full article

A diverse orchard with fruit fly hosts may provide information about trophic relationships, including new insights into beneficial insects. We evaluated the composition of the fruit fly complex to provide information on tephritid species, parasitoids and multitrophic interactions for the southern region of Minas Gerais, Brazil. Sampling was carried out using traps and by collecting fruits from plants and/or the ground according to availability/the fruiting period. Occurrences of Anastrepha amita Zucchi and A. punctata Hendel were recorded for the first time in the state of Minas Gerais, and new trophic associations were obtained for A. bahiensis Lima, A. bistrigata Bezzi, A. fraterculus (Wiedemann), A. obliqua (Macquart) and Ceratitis capitata (Wiedemann). Ten tephritid species were obtained from trap sampling, with C. capitata, A. fraterculus and A. obliqua being the most abundant. Five species of fruit flies and seven species of parasitoids were obtained from fruits. The braconid Doryctobracon areolatus (Szépligeti) was the most frequently collected among the parasitoid species. Pitanga (Eugenia uniflora L.) and purple guava (Psidium myrtoides O. Berg) fruits were classified as repositories of fruit fly parasitoids. Full article

Timing insecticide applications with insect emergence is critical for the management of cranberry pests like Sparganothis fruitworm (Sparganothis sulfureana, Lepidoptera: Tortricidae). The annual peak flight of S. sulfureana has previously been predicted using a degree-day model with a biofix date of 1 March; however, this biofix is not suitable for regions where winter and spring temperatures are warmer and flooding of cranberry beds is relied upon, which inhibits S. sulfureana development. In this study, we present two new degree-day models for predicting S. sulfureana peak flight based on six years of trapping data from New Jersey (USA): one with a biofix of 15 April, a date when drainage of cranberry beds occurs on average, and another using individual bed drainage dates. These models project peak flights at 525.5 and 521.0 degree-days using 15 April and water draw date as biofixes, respectively. These models can be used interchangeably, with both biofixes being suitable for regional grower guidance. Furthermore, differences in S. sulfureana peak flight were observed across four cranberry varieties; however, the effect of variety was influenced by year (significant variety-by-year interaction). This year-to-year variation in peak flight was strongly associated with spring (April–May) temperatures. Using these models, we project that with climate change, the peak flight of S. sulfureana in New Jersey cranberry beds may occur up to a week earlier by 2050. The use of a region-specific biofix and variety-specific models will help to better refine degree-day models for S. sulfureana, allowing for improved timing of management strategies against this pest. Full article

Pest attacks, especially by Sphenophorus levis, are a factor affecting sugarcane production. As the pest’s life habits make chemical control difficult, efforts are focused on finding integrated management alternatives. It is therefore essential to study the biology of S. levis, using artificial diets for rearing the insect in the laboratory. Artificial diets are commonly used for rearing pest insects, providing specimens year-round even when they are present only seasonally in the field, as is the case with S. levis. However, there is no diet in the literature that provides viable egg-to-adult development for rearing pests in the laboratory. Recently, studies to optimize diets using software with an interactive approach have shown good results in diet development. This study aimed to develop an artificial diet for S. levis using Design-Expert^® software (Version 11) to enable development and viability comparable to insects in the wild. The multivariate approach consisted of initially varying six components of the diet and then varying the three components that most influenced viability and the development rate, providing viabilities of over 60% at the end of the S. levis cycle in both phases of the screening design. However, the physical characteristics of the diet, such as the water content and texture, proved to be preponderant factors for the proper development of the insect and should be considered when using its artificial diet using a suitable container and uncrushed wheat germ. Full article

Batkoa is a genus of entomophthoralean fungi often associated with insect epizootics, particularly in phytophagous hemipterans. Encapsulation has become a promising strategy for improving the shelf life and sporulation of these fungi post-application. This study aims to (i) compare the virulence of the submerged propagules and primary conidia of Batkoa sp. ESALQ1199 against Dalbulus maidis; (ii) formulate submerged propagules in calcium alginate beads with co-formulants; (iii) assess the colony-forming units and sporulation of encapsulated beads dried with different kaolin concentrations (0%, 2%, 4%, 8% and 10%); (iv) determine the shelf life of dried bead formulations containing 10% kaolin, comparing washed and unwashed beads treated with a 4% sucrose solution; and (v) assess the sporulation capacity of beads with 10% kaolin, washed and unwashed with 4% sucrose solution, over time under humid conditions. Our results demonstrated that primary conidia and submerged propagules effectively killed 82.4% and 57.8% of adult corn leafhoppers, respectively. Co-formulants maintained viability above 80% in dried propagules, while control samples dropped to 45%, indicating the sensitivity of submerged propagules to the drying process. Encapsulated Batkoa sp. retained the same concentration of viable propagules per bead and the number of conidia produced (sporulation) for 30 days at 28 °C. The sporulation of fresh beads increased during the incubation period, plateauing after 27 days. This suggests that Batkoa sp. beads can produce primary conidia under humid field conditions, serving as a potential inoculum source for new infections. Full article

Hiking trails may act as hotspots at the wildlife–human interface, posing an acarological risk for people and their pets. Ticks that are maintained in the environment by wild animals may quest on people walking along the trails. Assessing the risk of tick bites for people involved in outdoor activities is a further step in mitigating the risk of tick-borne diseases. This work describes the variation of tick abundance along a gradient of distances from hiking trails, where wildlife passage is favored by higher accessibility. Hiking trails with dense vegetation on the sides were sampled for ticks along a 100 m dragging transect, located in a natural park in North-Western Italy. Additional transects were replicated at 1, 2 and 4 m away from the trail on both sides. After morphological identification, descriptive statistics and modeling were applied to determine the abundance patterns across distances. Larvae were most abundant near the trail, peaking at 1 m and dropping sharply at further distances. Nymphs showed a more gradual and consistent decrease at progressing distance from the trail. Few adults were collected, preventing the identification of a clear trend. With higher tick abundance, the immediate vicinity of hiking trails may represent a source of acarological risk for humans and pets. Full article

The increase in acarological risk of tick bites is significantly driven by profound changes in landscape, which alter the density and distribution of wildlife that support tick populations. As a result of habitat shifts and land abandonment, which create environments conducive to tick proliferation, the risk of disease transmission to humans and animals is increasing. In this context, it is important to explore tick ecology by applying a comprehensive methodology. In this study, we examined the relationship between wildlife temporal occupancy and tick abundance in two distinct regions: an alpine hunting district and a natural park in the Apennines. For each sampling point, we calculated wildlife temporal occupancy from camera trap pictures and estimated ticks’ abundance from dragging transects in the area immediately surrounding camera traps. In modelling the relationship between those two variables, we included abiotic factors such as saturation deficit, normalized difference vegetation index, and altitude. Results show the importance of altitude and wildlife temporal occupancy (itself related to different habitat and land management characteristics) on the ecology of questing ticks. If employed in management decisions for natural environments, such information is useful to modulate the acarological risk and thus the risk of tick-borne pathogens’ transmission. Full article

The red spider mite, Tetranychus macfarlanei, is a serious pest of many cultivated crops in Bangladesh and other East-Asian and South-East Asian countries, in the Afrotropical, Oriental, and Palearctic regions. Sublethal concentration of pesticides, such as LC₁₅ and LC₃₀ (the concentrations that result in 15 and 30 percent lethality, respectively) impact reproduction, behavior, development, and physiology. This study assessed the effects of different concentrations of spirotetramat, an insecticide that disrupts lipid production, on the biological traits of T. macfarlanei. The LC₁₅, LC₃₀, LC₅₀, and LC₉₀ values were 2.16, 6.57, 20.54, and 332.81 mg·L⁻¹, respectively. Sublethal concentrations (LC₁₅ and LC₃₀) slightly reduced female fecundity but did not significantly affect development duration, pre-oviposition, oviposition period, or longevity compared to the untreated control group. Life table parameters differed between the treated and control groups, with significant reductions in the intrinsic rate of increase (r), the net reproductive rate (R₀), and the finite rate of increase (λ) for LC₁₅ and LC₃₀. LC₁₅ and LC₃₀ had negative effects on the intrinsic rate of increase for females. This study demonstrated that lower lethal concentrations of spirotetramat compromised survivability and negatively impacted the life-table parameters of subsequent generations of T. macfarlanei. These findings highlight the importance of sublethal effects in pest control, offering valuable insights for developing more effective and sustainable integrated pest management strategies. Full article

Monitoring Tetranychus urticae Koch in cotton crops is challenging due to the vast crop areas and clustered mite attacks, hindering early infestation detection. Hyperspectral imaging offers a solution to such a challenge by capturing detailed spectral information for more accurate pest detection. This study evaluated machine learning models for classifying T. urticae infestation levels in cotton using proximal hyperspectral remote sensing. Leaf reflection data were collected over 21 days, covering various infestation levels: no infestation (0 mites/leaf), low (1–10), medium (11–30), and high (>30). Data were preprocessed, and spectral bands were selected to train six machine learning models, including Random Forest (RF), Principal Component Analysis–Linear Discriminant Analysis (PCA-LDA), Feedforward Neural Network (FNN), Support Vector Machine (SVM), k-Nearest Neighbor (kNN), and Partial Least Squares (PLS). Our analysis identified 31 out of 281 wavelengths in the near-infrared (NIR) region (817–941 nm) that achieved accuracies between 80% and 100% across 21 assessment days using Random Forest and Feedforward Neural Network models to distinguish infestation levels. The PCA loadings highlighted 907.69 nm as the most significant wavelength for differentiating levels of two-spotted mite infestation. These findings are significant for developing novel monitoring methodologies for T. urticae in cotton, offering insights for early detection, potential cost savings in cotton production, and the validation of the spectral signature of T. urticae damage, thus enabling more efficient monitoring methods. Full article