Parasite-associated changes in host behavior are often framed as manipulation, especially when altered behavior benefits parasite transmission. In the Xenos vesparum/Polistes dominula system, infected wasps abandon nests, aggregate before hibernation, overwinter, and later join established nests; a sequence often described through zombie or puppet-master metaphors. Recent studies have tied this phenotype to caste-related plasticity, gene expression, neuroanatomy, and ecological context, but the causal distinction between active parasite control and passive activation of host responses remains unresolved. Here I argue that passive manipulation should be treated as a useful null model and possible evolutionary starting point: infection may trigger pre-existing host responses that the parasite subsequently exploits. Archived pseudo-parasite observations are presented as an illustration: a sterile nylon implant, with no capacity for signaling, was associated with reduced energy use and nest desertion, whereas encapsulation intensity did not predict metabolic change. These observations do not prove passive manipulation by X. vesparum, but they show that early components of the infected phenotype can be induced without a living parasite. More broadly, parasite-benefiting behavior should not be treated as sufficient evidence for parasite-designed control. Distinguishing active from passive manipulation requires experiments that compare true infection, mechanical insult, parasite secretions, and naturally occurring host alternative phenotypes.
BackgroundHydatid disease caused by Echinococcus granulosus is a zoonosis endemic in many parts of the world. While hepatic and pulmonary involvements are common, isolated splenic hydatidosis remains extremely rare, representing less than 4% of all cases. Diagnosis can be further complicated by false-negative serological tests.Case presentationWe report the case of a 31-year-old female presenting with isolated left upper quadrant pain. Physical examination and baseline laboratory tests were unremarkable. Abdominal ultrasound and computed tomography (CT) revealed a well-circumscribed, homogeneous, hypodense oval mass (50×57×56 mm) at the upper pole of the spleen with a thin wall displaying a focal calcification. Hydatid serology was negative. Given the high suspicion of a hydatid cyst, pre-splenectomy immunizations were administered, and the patient underwent an exploratory laparoscopy. Intraoperative findings confirmed a splenic hydatid cyst, and a total laparoscopic splenectomy was performed. The postoperative course was uneventful. Histopathological examination confirmed the diagnosis.ConclusionClinicians should maintain a high index of suspicion for hydatid disease in patients presenting with cystic splenic masses in endemic areas, even in the presence of negative serology. Laparoscopic splenectomy is a safe and effective approach when strict hydatid safety measures are respected.
Elucidating the target of an antiparasitic small molecule can aid in the drug development process. However, various technical challenges related to parasite biology prevent timely target identification. Microscopy methods determining the co-localization of a drug with subcellular markers is a powerful approach that provides evidence of its localization within the cell. This technique can help pinpoint the primary site of action of novel therapeutics, which can assist in elucidating their mode of action. Intrinsically fluorescent drugs allow for subcellular localization without extensive medicinal chemistry. We imaged the intrinsically fluorescent drugs PRC1590 and quinine with digestive vacuole stains to determine these compounds’ localization in the malaria parasite, Plasmodium falciparum. We observed that imaging intrinsically fluorescent compounds often produces imaging artifacts due to spectral overlap and autofluorescence of P. falciparum, resulting in false positive co-localization findings. Our work outlines critical methodological considerations when studying subcellular localization of intrinsically fluorescent antimalarials.
IntroductionGiardiasis, caused by Giardia duodenalis, remains one of the most relevant enteric parasitic diseases in Brazil, affecting both humans and animals. This systematic review aimed to analyze the occurrence of Giardia spp. in Brazil from a One Health perspective, integrating epidemiological and molecular evidence related to parasite circulation among different hosts and environments.MethodsThe review was conducted in accordance with the PRISMA 2020 guidelines, using searches in the PubMed, LILACS, and SciELO databases for studies published between 2016 and March 2026.ResultsA total of 114 studies involving humans, animals, and environmental samples were included. Only nine of these studies (7.9%) adopted a genuinely integrated One Health design that simultaneously evaluated two or more compartments, and assemblage-level molecular characterization was available for only 17 studies (14.9%); these proportions should be considered when interpreting the One Health framing and the molecular inferences of this review. Substantial methodological heterogeneity was observed across studies, encompassing different coproparasitological, immunological, and molecular methods. In humans, occurrence was higher in vulnerable populations and in areas with inadequate basic sanitation. Among animals, dogs, cats, cattle, and wildlife stood out as important hosts. In environmental samples, a high frequency of detection was recorded in water, sewage, and food. Molecularly, assemblages A and B predominated, both associated with zoonotic and anthroponotic transmission.DiscussionThe findings reinforce the importance of integrated surveillance and One Health approaches for the control of giardiasis in Brazil.
IntroductionAngiotensin II (Ang II) has been proposed to protect from severe malaria by killing the parasite and maintaining the blood-brain barrier integrity by acting through type 1 (AT1R) and type 2 (AT2R) receptors. However, this protection from severe malaria is counterproductive in adulthood as the elevated plasma Ang II puts the individual at risk for developing hypertension. Various natural and synthetic peptides of Ang II have been explored to check its antiplasmodial actions despite Ang II being a significant vasopressor via its actions through AT1R. Therefore, to be able to explore Ang II as a potential antiplasmodial agent, it is important to demonstrate its IC50 against P. falciparum in vitro and its minimum effective concentration required for activation of AT1R. It is desirable that IC50 of Ang II against P. falciparum remains below the threshold for AT1R activation and hence to verify this, the current study was planned as there are no previously published reports for determining the threshold Ang II concentration for AT1R activation. MethodsFor invasion inhibition assay, Pf-infected RBCs (schizonts) were incubated with four different concentrations of Ang II for 16 hours. The activation of AT1R and AT2R in the presence of Ang II (from 10–9 M to 10–7 M) was tested by calcium and cGMP signaling assays, respectively using the human brain microvascular endothelial cell line as an in vitro model. ResultsEffective Ang II concentration among all tested concentrations was found to be 10–6 M against Plasmodium falciparum invasion. Statistically non-significant and negligible responses in AT1R and AT2R activation were observed below the desired Ang II concentration of 10–6 M.DiscussionThe results indicate that the IC50 of Ang II against P. falciparum is below the threshold for AT1R activation. However, the minimum effective Ang II concentration required for AT1R activation remains unanswered which demands further improvement in experimental designs.
IntroductionSchistosomiasis is a neglected tropical disease caused by parasitic worms of the genus Schistosoma. As schistosomiasis control programs approach elimination as a public health problem, there is an urgent need for sensitive diagnostic assays that can easily be deployed in the field at low cost. For schistosomiasis transmission interruption and surveillance use cases, the diagnostic Target Product Profile (TPP) proposed a two-step testing strategy involving an initial point-of-care screening test capable of detecting either current or former infections with sensitivity > 0.95, specificity > 0.80, and result stability ≥ 0.5 hours. To meet this need, Drugs and Diagnostics for Tropical Diseases designed two novel rapid diagnostic test (RDT) prototypes that detect antibodies against recombinant Schistosoma mansoni antigens: Sm25 and Sm29.MethodsWe evaluated the performance of these RDT prototypes using serum, whole blood, and dried blood spots (DBS). RDT results were determined by two visual readers and a Lumos automated reader, which also provided a quantitative readout of test line intensity. Lumos results were used to quantify test line stability over time. Further, we compared RDT results to other serologic assays (ELISA and the multiplex bead assay) that detect antibodies against Sm25, Sm29 and two additional S. mansoni antigens.ResultsWhile both Sm25 and Sm29 RDTs exhibited high specificity and stability that surpassed TPP criteria, their sensitivity fell short of TPP goals. Sensitivity was highest with serum, followed by DBS, then whole blood, which would be the most useful for point-of-care settings. In addition, we identified a gap in the ability of currently used recombinant antigens to detect all people infected with S. mansoni, regardless of test platform.DiscussionOur findings underscore that while these prototypes represent a promising start, there is still a case for novel antigen discovery and generation of RDTs with increased sensitivity to meet TPP criteria.
Strongyloidiasis is an intestinal parasitic disease caused by Strongyloides stercoralis, a soil-transmitted nematode. It is a common infection in Southeast Asia, including India, and is related to poor sanitation, rural residence, barefoot walking, and occupational exposure to soil. We report a case of a 71-year-old male farmer from rural Gorakhpur, Eastern Uttar Pradesh, who presented with intermittent watery diarrhoea for 2 years and tenesmus for 15 days. He was admitted with a diagnosis of fever of unknown origin. Routine stool microscopy revealed motile rhabditiform larvae of Strongyloides stercoralis, which were identified by their characteristic morphology, including a short buccal capsule and prominent genital primordium. Haematological examination revealed mild anaemia and eosinophilia. No other ova, cysts, or trophozoites were observed in the stool samples. The patient was treated with 200 µg/kg/day ivermectin for 2 days and showed clinical improvement. This case highlights the importance of routine stool microscopy in patients with chronic gastrointestinal complaints, especially in elderly patients from rural agricultural backgrounds
IntroductionCryptosporidiosis is a prevalent diarrheal disease in young calves caused by the zoonotic protozoan parasite Cryptosporidium parvum. The etiology of the disease is multifactorial. This case–control study investigated herd-level risk factors associated with clinical cryptosporidiosis on dairy farms.MethodsThe case farms (n=77) were Finnish dairy farms with clinical, laboratory-confirmed cryptosporidiosis and the control farms (n=152) were Finnish dairy farms without any recent clinical calf diarrhea outbreaks recorded in the most recent veterinarian's herd health visit. Control farms were not tested for the presence of C. parvum. Data were collected on overall herd health, management practices, environmental factors, and other factors potentially affecting the care of the calves. The data were analyzed with multivariable logistic regression.ResultsThe results indicate that a large herd size, cattle transfers between farms, insufficient isolation of sick calves from healthy ones, insufficient time for calf care, and five or more individuals involved in daily cattle work were all associated with increased risk of cryptosporidiosis.DiscussionThe findings of this study suggest that several herd-level management factors were associated with the occurrence of cryptosporidiosis on dairy farms, and the external and internal biosecurity of farms should be improved. Information on potential factors predisposing to cryptosporidiosis can be used to target preventive management practices more effectively on cattle farms to prevent cryptosporidiosis in calves.
BackgroundAccurate and accessible point-of-care testing for urogenital schistosomiasis (UGS) is vital for control and prevention in sub-Saharan Africa. Point-of-care (POC) rapid diagnostic tests with high sensitivity for both high and low parasite burdens have been developed. These tests need to be assessed for their applicability in poorly resourced UGS-endemic areas so that control programs can be initiated, and improved screening and routine diagnosis can be implemented.MethodsThis diagnostic test accuracy (DTA) review evaluates the sensitivity and specificity of eligible field-based index tests compared to laboratory-based reference tests for the diagnosis of UGS among individuals from Africa. Four databases were systematically searched for DTA studies on S. haematobium-exposed patients in endemic settings from 2000 to 2026. Methodological quality was assessed using the QUADAS-2 tool. Using the variability of test thresholds, a bivariate or HSROC model was used to calculate the diagnostic performance for each eligible test. Heterogeneity and subgroup analyses were conducted for the following variables: reference-standard comparators, age groups, and prevalence settings.ResultsTwenty-nine studies were evaluated, in which nine different POC and rapid tests were eligible, and four were included in a meta-analysis. Two field-based molecular tests, loop-mediated isothermal amplification (LAMP) and recombinase polymerase amplification (RPA), demonstrated high accuracy (sensitivity, 94.7%; specificity, 66.4%; and sensitivity, 94.1%; specificity, 96.6%, respectively). The immunochromatographic-rapid diagnostic test (ICT-RDT) and S. mansoni cercarial transformation fluid RDT (SmCTF-RDT) serological tests are easy-to-use POC cassettes and have high sensitivity (98.6% and 98.4%, respectively) but require a portable centrifuge to obtain serum samples. Other serological tests: dipstick dye immunoassay (DDIA) and indirect haemagglutination assay (IHA) had lower sensitivities (64.8% and 59.5%, respectively). The POC circulating cathodic antigen test (POC-CCA) demonstrated a sensitivity of 49.8% and specificity of 77.0% and has low diagnostic accuracy for S. haematobium. Portable and mobile-phone microscopes (sensitivity, 81.5%, specificity, 91.4%) were less sensitive than conventional microscopy but can have benefits in field-based low-resource laboratories.ConclusionFurther validation with improved reference standards is required to assess the diagnostic accuracy of many of the tests identified. RPA and LAMP emerged as promising field-applicable rapid tests for schistosomiasis control.
IntroductionStrongyloides stercoralis is the main cause of human strongyloidiasis, but increasingly, presumably mostly zoonotic, human infections with S. fuelleborni are reported. Recently, a number of studies investigated the population structures, host specificities and zoonotic potentials of these two species, using molecular taxonomy. This is the first such study from Sri Lanka.MethodsWe collected stool samples from humans, dogs and monkeys and used the Baermann after culture method to isolate individual live Strongyloides worms and determined parts of the cox-1 (mitochondrial) and the 18S rDNA (nuclear) and, for a subset, whole genome sequences.Results and discussionDespite a predicted high prevalence, we did not detect any Strongyloides in 126 human stool samples from the plantation sector. This may reflect the impact of improvements in sanitation and hygiene, reducing the worm burden to below our detection threshold. On the other hand, we observed a rather high incidence of S. fuelleborni in monkeys from within a university campus. Unexpectedly, also the two Strongyloides positive dogs we found on campus passed S. fuelleborni, one along with the expected S. stercoralis. Based on the mitochondrial sequences, the S. fuelleborni formed three subclusters within the previously described Asian clade. At the nuclear 18S rDNA locus, all S. fuelleborni carried haplotypes that had previously been described in Asia but some were heterozygous for one Asian allele and one that had so far been considered Africa specific. This suggests that Sri Lanka might be a hybridization zone for the two clades. The S. stercoralis found in this study clustered with the previously proposed ‘human and dog shared’ type of S. stercoralis.ConclusionsThe presence of possible hybrids between the African and the Asian clade of S. fuelleborni and the presence of this species in dog faeces are interesting findings that need to be confirmed in additional studies. The presence of S. stercoralis and S. fuelleborni in animal faeces within the University premises, including the dormitory and the swimming pool area, raises concerns of possible exposure of the University community to these parasites in spite of sanitary conditions that render human to human transmission unlikely.
Introduction:Kinetoplastids are one of two groups of euglenozoans that have compartmentalized the enzymes of metabolic pathways, including glycolysis, into a peroxisome-derived organelle called a glycosome. Several ideas have emerged regarding the evolutionary pressures that drove and are maintaining compartmentalization of these typically cytosolic enzymes. For example, their compartmentalization might result in superior efficiency in remodeling enzyme relative abundances in response to changing environmental conditions. We wished to empirically test the merits of this explanation. We began with the presumption that the abundances of glycosome-compartmentalized enzymes are broadly affected by changes in extracellular environment, similar to how they vary between life stages of the model kinetoplastid Trypanosoma brucei. Our hypothesis was that abundances of glycosome-localized enzymes in multiple kinetoplastids would alter as a result of their extracellular environment. Methods:Six different kinetoplastid species, including both dixenous and monoxenous parasites, were evaluated in culture for their response to extracellular nutrient and oxygen availability in terms of their expression of glycosome-localized enzymes. We analyzed their growth rates and utilized immunoblotting to measure abundances of glycosome-localized or partially-localized enzymes and cytosolic enolase in the different culture conditions. Results:We found the tested enzyme abundances to be largely consistent. Oxygen availability and slow removal of nutrients from the extracellular environment resulted in only minor changes in enzyme abundance. Only abrupt replenishment of culture nutrients resulted in enzyme abundance responses - typically a modest decrease in both cytosolic enolase and the glycosome-localized enzymes. Discussion:Results suggest that there is little evidence that parasites respond to external nutrient or oxygen availability through alterations in relevant enzyme abundances, at least absent life cycle transitions. Thus, our study does not provide support for the idea that efficient and coordinated remodeling of ratios of metabolic enzymes was an evolutionary driver of metabolic enzymes' compartmentalization in the glycosome. Further, it suggests that it may be relevant to test whether posttranslational modifications and/or changes to enzyme localization are mechanisms trypanosome utilize to adjust specific metabolic activity when needed.
Introduction:Giardia duodenalis and Cryptosporidium spp. are ubiquitous enteric protozoans of significant public health and veterinary concern. Despite their global importance, molecular epidemiological data concerning companion animals in Vietnam remain limited. Methods:This cross-sectional study evaluated the prevalence, investigated the specific Giardia assemblages and Cryptosporidium species, and identified risk factors associated with these parasites in 362 owned dogs in Dak Lak province, Central Vietnam. Genomic DNA extracted from fecal samples was screened using nested PCR targeting the small subunit ribosomal RNA (SSU rRNA) locus, followed by sequencing of positive amplicons. Epidemiological risk factors were assessed using multivariable logistic regression. Results:The overall prevalence of G. duodenalis was 8.0% (29/362; 95% confidence interval [CI]: 5.6-11.3%), whereas Cryptosporidium spp. DNA was not detected. Sequencing of 18 Giardia-positive isolates exclusively identified the canine-specific assemblage D. Multivariable analysis revealed that direct contact with other dogs (adjusted odds ratio [aOR] = 7.55; 95% CI: 1.69-33.82; P = 0.008) and unbathed status (aOR = 0.30; 95% CI: 0.11-0.83; P = 0.021) were significant predictors of infection. Host demographics, location, outdoor access, and deworming history had no significant association with Giardia positivity. Discussion:The exclusive detection of assemblage D indicates that dogs in this rural setting currently pose a minimal direct zoonotic risk to the local human population. These findings emphasize the importance of improving canine management practices, particularly through proper hygiene and the restriction of uncontrolled interactions between dogs, to mitigate transmission risks.
A significant economic impact to the agriculture and declining drug efficacy due to anthelmintic resistance lead to the search for novel intervention approaches against the zoonotic liver fluke Fasciola hepatica. A cost-effective strategy is to induce protective immunity by vaccination. However, adaptation of the parasite to evade the host immune response hampers classical vaccine development. Therefore, an ideal protective epitope would not be subjected to this evolutionary selection. Antigens, which are not exposed to the host’s immune system during a natural parasite infection, but which could be attacked by vaccine antibodies, have been shown to be valid candidates, especially those expressed in the gut of blood-feeding and tissue-dwelling helminths. Overall, helminth gut-associated glycoproteins—including hidden antigens—serve as a rich source for novel anthelminthic vaccine candidates. Here, we purified F. hepatica gut-associated glycoproteins assisted by lectin-affinity chromatography and specific monoclonal antibodies (mAbs). The protective capacity was demonstrated in vitro by feeding the mAbs to cultured F. hepatica, which impaired fluke survival assessed by reduced motility, fecundity, and reduced active secretion. Furthermore, we could demonstrate a binding of different mAbs to F. hepatica gut structures, indicating that liver flukes dine from their environment. Characterisation of the complex gut-associated glycoproteins by a quantitative affinity-enrichment proteomics approach revealed a list of 36 proteins with potential for further vaccine development. Given a conservation of many of these candidates in different F. hepatica life stages indicated by available transcriptomic data, such parasite gut-associated glycoproteins serve as a rich source for novel vaccines, directed also against early developmental stages responsible for pathological liver damage.
Strongyloides stercoralis is a soil-transmitted helminth that is responsible for an estimated 300–600 million human infections worldwide, mostly in impoverished areas of tropical and sub-tropical countries. To date, S. stercoralis is also the only human-parasitic nematode that is amenable to the generation of stable transgenic or mutant lines that can be maintained indefinitely by passage through a laboratory host, the Mongolian gerbil. Because of its health significance and ease of genetic manipulation, S. stercoralis has rapidly emerged as a model system for understanding the molecular and cellular basis of nematode parasitism. In this mini-review, we discuss the approaches used to generate transgenic and mutant S. stercoralis, with an emphasis on approaches for generating stable transgenic or knockout lines. We also discuss how these approaches are enabling new insights into the basic biology of these highly pathogenic, and sometimes deadly, human parasites.
A Ryukyu long-furred rat (Diplothrix legata) rescued on Amami-Oshima Island, located in the southwestern Japan, exhibited neurological signs, including nystagmus and ataxia, and died six days after supportive treatment. Gross and histopathological examinations revealed nematodes in the brain, lungs, and heart. In the meninges, immature worm sections were associated with marked inflammatory thickening. Pulmonary lesions included adult worms, eggs, and larvae accompanied by hemorrhage, edema, thrombosis, and extensive necrosis with concurrent Aspergillus infection. Mitochondrial cytochrome c oxidase 1 sequences obtained from the nematodes identified the ac1 lineage of Angiostrongylus cantonensis, a haplotype previously reported from mainland Japan and Amami-Oshima Island, but distinct from the lineage common on the neighboring islands of Okinawajima and Tokunoshima. This case supports the occurrence of angiostrongylosis in the Ryukyu long-furred rat and suggests that this species may manifest both neurological and respiratory disease manifestations. Further epidemiological investigations targeting invasive rodents of the genus Rattus, intermediate host, namely terrestrial gastropods (e.g., snails and slugs), and potential paratenic hosts (e.g., amphibians and reptiles), are warranted to clarify the transmission dynamics of A. cantonensis within the Amami Islands and to assess its potential impact on this endangered endemic rodent.
BackgroundSoil-transmitted helminths (STHs) continue to affect millions of people worldwide, but the role of animals in sustaining transmission remains poorly understood. This study examined the diversity and zoonotic potential of hookworms and Strongyloides across humans, dogs, and nonhuman primates (NHPs) in three different study areas located in three ecological zones in Ghana, where humans live in close contact with domestic dogs and free-ranging nonhuman primates, creating opportunities for cross-species parasite exchange.MethodsStool samples from humans, dogs, and nonhuman primates were analysed using the Baermann technique after faecal culture. Single larvae and young adult worms were genotyped at the nuclear small subunit (SSU) Hypervariable Regions (HVR) I and IV, ITS-2 and the mitochondrial cox-1 markers. Species identities and genetic relationships were explored using Neighbour-joining and Maximum-likelihood phylogenies in MEGA 12 and a Median-joining haplotype network in POpART.ResultsTwo major clusters of hookworms were detected in our study area, both belonging to the genus Ancylostoma. One cluster is closely related to a species group containing A. caninum, A. duodenale, A. ceylanicum, and A. tubaeforme. The other cluster appears to belong to the species A. braziliense. Several haplotypes in both clusters were shared between humans and dogs, indicating active zoonotic transmission. For Strongyloides, humans carried S. stercoralis, monkeys carried S. fuelleborni, and in dogs we found a Strongyloides that appeared closely related to S. papillosus.ConclusionsOur findings reveal substantial hookworm diversity but no evidence for host specificity, which suggests zoonotic transmission at the human-dog interface. The, based on previous literature, unexpected recovery of A. braziliense larvae from human stool suggests that the zoonotic potential of this species may be greater than previously assumed. In contrast to several recent studies in Asia, we found no overlap between Strongyloides spp. in humans and animals but the number of Strongylodies spp. infected hosts was very small. Our results reinforce the need for including animals that live in close proximity to humans in STH studies and control considerations, following a One Health approach.
Malaria remains a major public health concern in Cameroon, with Plasmodium falciparum responsible for most morbidity and mortality, particularly among children under five. In response to rising cases, Cameroon began implementing the RTS,S/AS01 malaria vaccine in early 2024. Given the vaccine’s strain-specific efficacy, understanding haplotypic diversity is critical for evaluating long-term impact. We analyzed 100 P. falciparum-positive dried blood spots collected in Mapoussere, Kaele Health District (2022–2023). Using the 4CAST amplicon sequencing assay, we targeted four genes: csp (circumsporozoite protein), ama1 (apical membrane antigen 1), sera2 (serine repeat antigen 2), and trap (thrombospondin-related anonymous protein). Haplotypes were identified using SeekDeep, and diversity metrics including heterozygosity (He), nucleotide diversity (π), and selection statistics (Tajima’s D, Fu and Li’s D*, F*) were computed. We successfully genotyped csp in 35% of samples, identifying 22 haplotypes (He = 0.908; π = 0.021). The vaccine-matched haplotype was present in 20% of genotyped infections. The T cell TH2 and TH3 epitopes of csp showed signs consistent with balancing selection. Both ama1 and sera2 exhibited higher genotyping success and diversity, with ama showing significant Tajima’s D values. Within-participant haplotype counts were highest for ama1 (mean = 2.8), followed by sera2 (2.1), csp (1.3), and trap (1.2). This study provides a baseline of P. falciparum haplotype diversity in a vaccine-targeted region. The presence of vaccine-matched strains and high diversity in TH2/TH3 epitopes in csp may influence vaccine efficacy. Continued molecular surveillance is essential to monitor antigenic shifts and guide future strategies.
Onchocerciasis is still a major health burden in sub-Saharan Africa and Yemen, where many cases occur as control efforts face persistent obstacles, while smaller, well-defined transmission foci remain in Brazil and Venezuela. Caused by the filarial nematode Onchocerca volvulus and transmitted by blackflies, the disease causes progressive disability, economic loss, and hampers community development. Despite decades of mass drug administration with ivermectin, the inability of the drug to kill adult worms, increasing concerns over resistance, and the lack of effective vaccines continue to hinder elimination strategies. This review provides an overview of the disease, discussing its transmission dynamics, pathogenesis, clinical manifestations, diagnosis, and treatment. It also examines the immune-mediated responses that drive tissue damage and chronic morbidity, with an emphasis on skin and ocular complications. We highlight the need for rapid, non-invasive, and cost-effective diagnostic tools to enhance disease surveillance and assessment of treatment. Finally, we discuss the limitations of current therapies and recent progress in vaccine development, particularly subunit and multi-epitope vaccine candidates identified through reverse vaccinology approaches. Together, these insights reinforce the need for integrated strategies, combining improved diagnostics, novel treatments, and vaccines, to drive progress toward onchocerciasis elimination.
Introduction:Flea infestation remains a major clinical and public health concern in cats due to its negative impact on animal welfare and its role in the transmission of zoonotic pathogens. Effective flea control under routine field conditions is essential for integrated parasite management in companion animals. The aim of this study was to evaluate the clinical performance of a topical formulation combining ivermectin, imidacloprid, and praziquantel for flea control in domestic cats under field conditions. Methods:A total of 142 naturally infested cats of varying ages, sexes, and body conditions were included in the study. All animals received a single topical application of the evaluated formulation. Clinical and parasitological assessments were performed on Days 0, 1, 7, 14, and 30 post-treatment using standardized flea counts, pruritus scores, and dermatological lesion scores. Treatment effectiveness was assessed using within-subject pre-post comparisons. Effective flea control was defined as a marked reduction in the proportion of flea-positive cats relative to baseline, accompanied by concurrent clinical improvement. Results:The proportion of cats free of detectable fleas exceeded 91% by Day 7 and approached 95% by Day 30 post-treatment. Significant clinical improvement was observed during the first two weeks, including reductions in pruritus intensity and dermatological lesion scores. Treatment response did not differ according to sex or age, indicating consistent clinical performance across diverse feline subpopulations. No adverse effects were reported throughout the study period. Discussion:The findings indicate that the evaluated topical combination provides consistent and clinically meaningful flea control in domestic cats under routine field conditions, supporting its use as part of integrated parasite management strategies in companion animals. However, the absence of a negative control or active comparator group represents a limitation of the study; therefore, treatment effectiveness was assessed using within-subject comparisons rather than established regulatory efficacy benchmarks.
