Mathematical models of plague dynamics provide insight into zoonotic transmission processes and epidemic persistence but often neglect stochastic effects and seasonal variability. In this study, we examine how seasonal variability influences zoonotic disease transmission through a rat-flea-human plague model. Periodic environmental forcing modulates rat abundance, flea survival, and biting activity, generating time-dependent rates that capture realistic ecological seasonality. To represent demographic randomness, we formulate a continuous-time Markov chain (CTMC) model and apply a multi-type branching process approximation near the disease-free equilibrium (DFE) to derive approximate disease extinction probabilities using probability generating functions (PGFs) and the backward Kolmogorov differential equation (BKDE). Our results show that random fluctuations can prevent an epidemic outbreak even when the seasonal reproduction number satisfies R 0 > 1 . We also quantify the spillover probability arising from a single infectious flea, demonstrating that seasonal forcing significantly alters outbreak risk. Along with this, an expression for time to extinction is also derived. To ensure biological understanding, we estimate model parameters from historical data using a Bayesian Markov chain Monte Carlo (MCMC) approach implemented via the Delayed Rejection Adaptive Metropolis (DRAM) algorithm. Through this analysis, we highlight the critical role of seasonality in shaping outbreak risk and demonstrate the limitations of relying solely on deterministic models.

Ultrasonography is particularly useful in children because it can be repeated without ionizing radiation and can be adapted to the clinical question during the examination. A 10-year-old boy with right lower quadrant pain, right leg pain, and a limp was referred with suspected acute appendicitis. A comprehensive diagnostic ultrasound examination of the abdomen demonstrated a normal appendix and an enlarged lymph node corresponding to the site of right lower quadrant tenderness. During the examination, conversation with the patient and his mother disclosed household cat ownership, frequent exposure to cat fleas, and multiple flea bites. The abdominal findings, exposure history, and pre-existing right leg symptoms were shared with the clinical team. At the physician's request, additional ultrasound evaluation of the right popliteal region demonstrated a second enlarged, tender lymph node. Superb microvascular imaging showed nonspecific vascular signals predominantly near the hila of both nodes. Serologic and molecular testing for Bartonella henselae was not performed; therefore, cat-scratch disease remained a clinical suspicion rather than a confirmed diagnosis. After azithromycin treatment, the symptoms improved and both lymph nodes decreased in size on follow-up ultrasonography. This case does not establish an ultrasonographic diagnosis of cat-scratch disease. Rather, it illustrates how ultrasonography provided anatomic correlates for symptoms at two sites, complemented the information available from clinical assessment alone, and supported noninvasive follow-up.

Background: Parasitic skin-related conditions represent a frequent and evolving challenge in human dermatology, as they often mimic other dermatoses, and are increasingly complicated by therapeutic resistance. With this study, we aimed to provide a practical, clinician-oriented overview of our experience, contextualising it within the current literature. Materials and Methods: We conducted a retrospective, single-centre observational study, reporting a case series of 88 patients diagnosed with parasitic or arthropod-related skin infestations at the San Raffaele Hospital Dermatology Unit (Milan) between 2019 and 2024, and integrated a concise narrative review of contemporary evidence on diagnosis, non-invasive imaging and management. For each case, we documented clinical presentation, dermoscopic or reflectance confocal microscopy (RCM) findings, and treatment response. Non-invasive tools (dermoscopy, videodermoscopy, RCM) were used when appropriate. Results: The spectrum of conditions included flea bites, bed bug bites, cutaneous larva migrans, subcutaneous dirofilariasis, Dermanyssus gallinae dermatitis, pediculosis, tick bites (including Lyme disease), myiasis, scabies, and cutaneous leishmaniasis. One case of eosinophilic dermatosis of haematologic malignancy was also considered due to its possible association with arthropod bites. Non-invasive imaging was critical in confirming suspected infestations, particularly in ambiguous cases or when invasive testing was not feasible. Several cases highlighted suspected therapeutic resistance: a paediatric pediculosis and three adult scabies cases required systemic therapy after standard regimens failed, raising concerns over putative resistance to permethrin and pyrethroids. In dirofilariasis, the persistence of filarial elements visualised by RCM justified the extension of antiparasitic therapy despite prior surgical removal. Conclusions: Our findings underline that accurate diagnosis, early intervention, and tailored treatment remain essential for the effective management of cutaneous infestations. The observed vast spectrum of isolated parasites reflects broader health and ecological dynamics, including zoonotic transmission, international mobility, and changing environmental conditions. At the same time, diagnostic delays, inappropriate treatments, and neglected parasitic diseases continue to pose significant risks. To address these challenges, clinicians should remain alert to atypical presentations, and consider a multidisciplinary approach including the consultation with parasitologists and veterinarians, as well as the incorporation of high-resolution imaging and alternative therapeutic strategies into their routine practice.

Cat scratch disease (Cat scratch fever) causes a febrile illness with subacute regional lymphadenopathy. The agent of infection is Bartonella henselae. In most cases, there is a spontaneous resolution within 2 to 4 weeks. More severe and disseminated disease can occur in both immunocompetent and immunocompromised hosts. Cat scratch disease was initially described in the 1930s, and the association of the illness with cats was identified in the 1950s. Cat scratch should be considered in the differential diagnosis of any acute, subacute, or chronic lymphadenopathy.[1][2][3]

Based on a large-scale bibliometric dataset, domestic dogs (Canis lupus familiaris) emerge as the most frequently cited host species in the context of zoonoses, being mentioned in at least 10% of publications for nearly a quarter of the pathogens recognized as zoonotic to humans. This review examines the contributions of pet and stray dogs to various zoonotic transmission pathways, highlighting some mismatches between research focus and actual epidemiological risks. Among zoonotic agents associated with dogs, helminths are disproportionately represented in the literature compared to bacteria and viruses. Pet and stray dogs exhibit distinct zoonotic risks due to differences in exposure patterns and human interactions. Stray dogs are frequently involved in environmentally transmitted diseases, particularly soil- and water-borne parasites, due to uncontrolled defecation and opportunistic behavior. Conversely, pet dogs pose greater risks for direct transmission, particularly via bites, close contact infections, and antimicrobial-resistant bacteria. From a public health perspective, integrating dogs into One Health surveillance frameworks is crucial. Routine genomic monitoring of stray dogs could allow early detection of emerging zoonoses, while large-scale deworming programs, improved sanitation infrastructures, and responsible pet management would mitigate both environmental and direct transmission risks. Vector-borne zoonoses require differentiated control measures, including antiparasitic treatments for tick- and flea-borne infections and environmental interventions for mosquito- and sandfly-borne pathogens. This review focuses on pet and stray dogs only, due to the lack of consistent definitions and data availability for other canine categories. Future research should refine ecological and behavioral studies and dog-host interaction analyses to better quantify the zoonotic risks associated with each dog ecotype and guide targeted intervention strategies. This approach enables a more precise zoonotic risk stratification and contributes to effective disease prevention at the human-animal-environment interface.

Background/Objectives: The accurate identification of insect bites from images of skin is daunting due to the fine gradations among diverse bite types, variability in human skin response, and inconsistencies in image quality. Methods: For this work, we introduce DeepBiteNet, a new ensemble-based deep learning model designed to perform robust multiclass classification of insect bites from RGB images. Our model aggregates three semantically diverse convolutional neural networks-DenseNet121, EfficientNet-B0, and MobileNetV3-Small-using a stacked meta-classifier designed to aggregate their predicted outcomes into an integrated, discriminatively strong output. Our technique balances heterogeneous feature representation with suppression of individual model biases. Our model was trained and evaluated on a hand-collected set of 1932 labeled images representing eight classes, consisting of common bites such as mosquito, flea, and tick bites, and unaffected skin. Our domain-specific augmentation pipeline imputed practical variability in lighting, occlusion, and skin tone, thereby boosting generalizability. Results: Our model, DeepBiteNet, achieved a training accuracy of 89.7%, validation accuracy of 85.1%, and test accuracy of 84.6%, and surpassed fifteen benchmark CNN architectures on all key indicators, viz., precision (0.880), recall (0.870), and F1-score (0.875). Our model, optimized for mobile deployment with quantization and TensorFlow Lite, enables rapid on-client computation and eliminates reliance on cloud-based processing. Conclusions: Our work shows how ensemble learning, when carefully designed and combined with realistic data augmentation, can boost the reliability and usability of automatic insect bite diagnosis. Our model, DeepBiteNet, forms a promising foundation for future integration with mobile health (mHealth) solutions and may complement early diagnosis and triage in dermatologically underserved regions.

Vector-borne diseases (VBDs) significantly impact global child health, with mosquito-transmitted infections like malaria and arboviruses accounting for a substantial portion of this burden. However, other arthropod-borne diseases-transmitted by vectors such as ticks, fleas, sand flies, lice, and triatomine bugs-also pose serious health risks to children worldwide. This review specifically excludes mosquito-borne diseases to concentrate on these less-discussed yet clinically important pediatric VBDs. We examine their clinical manifestations, diagnostic challenges, and treatment options, highlighting the unique vulnerabilities of children, including immature immune systems, behavioral factors, and communication barriers that can delay diagnosis. Additionally, we explore how environmental and anthropogenic factors, such as climate change and urbanization, are expanding the geographic range of these vectors, leading to the emergence of diseases like Lyme disease and leishmaniasis in new regions. By focusing on non-mosquito VBDs, this review aims to raise awareness and inform healthcare providers and public health practitioners about the comprehensive landscape of pediatric vector-borne diseases.

Besides causing allergies from their bites, fleas transmit the most notorious zoonotic pathogen, Yersinia pestis. They also harbor commensal bacteria in their guts. Here, the microbial communities of fleas were characterized using 16S rRNA Next-Generation Sequencing to understand microbial interactions and functions in areas with historical plague-outbreaks in Iran with the ultimate idea of ​​managing flea-borne diseases. Meriones persicus, Xenopsylla buxtoni and Bartonella spp. were identified as the dominant host, vector and bacterium, respectively. Six bacteria Bartonella, Sphingomonas, Wolbachia, Cardinium, Rickettsia and Ralstonia were identified as the most abundant genera in the microbiome of five flea species. More detailed surveys revealed substantial intrageneric variations (e.g. nine phylotypes for Bartonella) and the diverse nature (from biofilm-forming human pathogens to insect reproductive manipulators, and environmental microbes) for the bacteria studied. The fleas microbiome is largely affected by species and to a lesser extent by location, and circulates by both horizontal and vertical transmissions. The prevalence of Bartonella spp. infection in fleas highlights the potential to explore One Health approaches, particularly in addressing travel-related and zoonotic disease risks. Environmental drivers-such as climate change, habitat alteration, and host dynamics-shape flea microbiomes and influence disease risk, while concerns about antimicrobial resistance further complicate control efforts. Our findings advocate for coordinated strategies that combine public health education, ecological monitoring, and global collaboration to sustainably manage flea-borne diseases.

Fleas are ectoparasites of mammals and birds. Some species are known for their medical and veterinary importance. Particularly for humans and domestic animals, fleas are often merely nuisance species, but may also be disease vectors. Some well-known infectious diseases are transmitted from animals to humans by flea bites: murine typhus, spotted-fever, bartonelloses and plague. Particularly for plague, more than 80 species were reported vectors in the world and some are internationally renowned and have been the focus of studies over decades. In Madagascar, fleas are associated with two diseases namely tungiasis and plague. Tungiasis is neglected while it affects many primarily rural districts of the country. Plague is a public health concern and endemic districts are mainly focused in the highland regions. Although more than 40 flea species occur in Madagascar, this paper is focused on some species that are confirmed or suspected vectors of plague bacteria (Yersinia pestis Lehmann and Neumann, 1896) in Madagascar namely Xenopsylla cheopis Rothschild, 1903, X. brasiliensis Baker, 1904, Synopsyllus fonquerniei Wagner and Roubaud, 1932, S. estradei Klein, 1964, Pulex irritans Linnaeus, 1758 and Paractenopsyllus pauliani Lumaret, 1962, and reviews their origins and geographic distributions, bioecology, host preferences, vector competence regarding Y. pestis, and their roles in pathogen transmission.

Bartonella spp. are most often transmitted by arthropod vectors or animal bites and scratches. However, the vector species involved in the transmission of human bartonellosis remain poorly understood. This study investigated the presence of Bartonella in Triatoma rubrofasciata from Guangxi and Hainan provinces in China, evaluating its potential as a vector. Bartonella was identified in T. rubrofasciata samples through PCR amplification and sequencing of the ITS, gltA, and rpoB genes. The survival duration of Bartonella in triatomines, along with the potential for transovarial transmission was examined. Transmission experiments were conducted to determine whether T. rubrofasciata could transmit Bartonella to mice. Additionally, Bartonella spp. were also compared across rats, ticks, and cat fleas collected from the same regions. Results: Six Bartonella species were identified in T. rubrofasciata, including B. rochalimae, B. elizabethae, B. tribocorum, B. queenslandensis, B. silvatica, and B. coopersplainsensis. And the first three species are zoonotic. B. rochalimae and B. elizabethae were able to persist in T. rubrofasciata for at least eight weeks, although transovarial transmission of them was not observed. In comparison to rats, ticks, and cat fleas, T. rubrofasciata exhibited a higher diversity of Bartonella species. Laboratory experiments confirmed that B. elizabethae can infect mice through T. rubrofasciata bites or intraperitoneal injection of T. rubrofasciata feces. This study supports the hypothesis that T. rubrofasciata may serve as a vector for bartonellosis. These results broaden the current understanding of Bartonella transmission dynamics and highlight the potential role of triatomines in the spread of this disease.

Although often considered a historical disease, plague remains a modern-day public health concern with global relevance. Caused by the bacterium Yersinia pestis and transmitted to humans primarily through infected flea bites or contact with infected animals, plague persists worldwide, including parts of the southwestern United States. The disease presents in three main forms: bubonic, septicemic, and pneumonic. Bubonic plague, the most common form, is characterized by painful swollen lymph nodes known as buboes. Septicemic plague occurs when the infection enters the blood stream, while pneumonic plague, the most virulent and transmissible form, poses a serious bioterrorism threat due to its ability to spread via respiratory droplets and high fatality rate. Though rare today, with an average of seven cases annually in the U.S., plague still demands awareness and preparedness by emergency nurse practitioners and other clinicians. Early diagnosis, timely antibiotic treatment, and vigilant public health measures are critical to reducing its morbidity and mortality.

Understanding Kazakhstan's plague history is crucial for early warning and effective health disaster management. We used descriptive-analytical methods to analyze spatial data for human cases in natural plague foci in Kazakhstan during 1926-2003. The findings revealed 565 human cases across 82 outbreaks in Almaty (32.22%), Aktobe (1.59%), Atyrau (4.42%), Mangystau (21.24%), and Kyzylorda (40.53%) oblasts. Before antibiotic drugs were introduced in 1947-1948, major plague outbreaks occurred in 1926, 1929, 1945, 1947, and 1948, constituting 80.7% of human transmission. Plague spread through flea bites, camel handling, wild animal contact, aerosol transmissions, and rodent bites. Patients were up to 86 years of age; 49.9% were male and 50.1% female. Pulmonary cases were reported most frequently (72.4%), and person-to-person infection occurred at an incidence rate of 0.29 cases/10,000 population. Risk increased with human expansion into natural plague foci areas. Swift diagnosis and treatment are essential for curbing plague outbreaks in Kazakhstan.

Rodents are the reservoirs of the plague bacterium Yersinia pestis, which is transmitted through the bites of infected fleas. In this paper, we studied the distribution and abundance of fleas and rodents in the erstwhile endemic states and seaports of India from 2009 to 2019. The analysis showed that the Rattus rattus (Rr) was the major rodent species found in both Western (66.52 %) and Eastern (48.95 %) seaports of India and the other rodent species recorded were Bandicota indica (Bi) (16.68 % & 34.24 %), Bandicota bengalensis (Bb) (8.88 % & 16.02 %) Rattus norvegicus (Rn) (6.83 % & 0.70 %), Murines hurriane (Mh) (1.08 % & 0 %), Mus musculus (Mm) (0 % & 0.09 %), respectively. Only two flea species namely, Xenopsylla cheopis (X.c) and Xenopsylla astia (X.a) were recorded during the study period in Eastern and Western seaports. Among them, X. astia was found to be the dominant species (55.56 %) and followed by X. cheopis (44.44 %). Further, the female population of X. cheopis and X. astia was higher in both Western and Eastern seaports than the male population. Similarly, Rattus rattus (Rr) (82.43 %,) was the major rodent species found in erstwhile endemic states of India, followed by Tetera indica (Ti) (11.99 %,). Only northern endemic states (HP and UK) reported Rattus rattus terkiminasis (R.rt) (0.01 %). Four flea species namely, Xenopsylla cheopis (64.89 %), Xenopsylla astia (34.89 %), Stivalius ahalae (0.18 %), and Nosopsyllus fasciatus (0.02 %) were recorded from endemic states. The presence of rodents and vector fleas warrants sustained plague surveillance in and around seaports and endemic states.