Abstract Aquaculture has been recognized as one of the main solutions to the growing global food demand, as well as a significant resource for addressing the limitations imposed on wild fisheries. The most important fish species for Brazilian fish farming is Colossoma macropomum due to its zootechnical characteristics, economic and cultural importances. In cultivated systems, the presence of parasites can represent a major problem. Under these conditions, parasites of the phyla Acanthocephala and Platyhelminthes are commonly found parasitizing farmed fishes. This study aimed to investigate the helminth fauna and their parasitological indices in cultivated fish farms located in the municipalities of Imperatriz, state of Maranhão and in Rio Branco, state of Acre, Brazil. A total of 1,617 specimens of Monopisthocotyla were collected, and, among the endoparasites, 325 specimens belong to the phylum Acanthocephala and 10 specimens belonging to the class Trematoda were identified. The present study expands the known biodiversity and distribution of helminth parasites in South American aquaculture, providing new records for host-parasite associations and geographic locations in the states of Acre and Maranhão, Brazil.
Abstract Two new species of Protomicrocotyle are described as parasites of the gill filaments of Caranx hippos from the Gulf of Mexico coast, characterized using morphological, morphometric, and molecular methods. Multivariate statistics (principal component and discriminant analyses) were used for the morphometric analyses. Pairwise genetic distances (p-distances) and cluster analyses using the Neighbor-joining method were performed using partial sequences of CO1 mtDNA and 28S rDNA of the new species and partial sequences of other species of Protomicrocotylidae from GenBank. Protomicrocotyle eamsae sp. nov. differs morphologically from other congeners by the presence of a retractile glandulomuscular organ in the prohaptor, and Protomicrocotyle pritchardae sp. nov. differs from other congeners by the body length and by the arrangement, shape, and number of testes. The new species was recovered as a distinct group, separate from other protomicrocotylids, based on CO1 mtDNA and 28S rDNA analyses. The results of the morphometric analysis of 91 morphological variables and the molecular analysis support the assignment of the new species to Protomicrocotyle in Caranx hippos from Tecolutla, Veracruz, Mexico.
Abstract This study aimed to identify and analyze zoonotic parasites found in Scomberomorus cavalla and Trichiurus lepturus collected from the Mundaú-Manguaba Estuarine Lagoon Complex (CELMM), considering their commercial relevance and the associated risks to food safety and public health. A total of 34 fish were obtained from local fishermen, including 30 T. lepturus and four S. cavalla. The fish were necropsied and their internal organs were examined to identify parasites. Prevalence, abundance, and mean intensity of parasitic infections were calculated. In T. lepturus, the most prevalent (20%) nematode was Contracaecum sp., predominantly found in the coelomic cavity. In S. cavalla, the most frequently observed one (100% prevalence) was Hysterothylacium sp., with infections disseminated in the stomach, intestine, liver, and coelomic cavity. All identified parasites were documented for the first time in fish collected from this estuarine complex, CELMM, in Brazil, expanding their known geographical and ecological distribution. The presence of zoonotic parasites in commercially sold fish from CELMM poses a significant public health risk. Therefore, stringent sanitary inspection measures and public awareness initiatives are essential to mitigate contamination risks and ensure the quality of fish products intended for human consumption.
Abstract Dirofilaria immitis remains a significant canine pathogen in Brazil despite the long-standing availability of chemoprophylactic products. Higher infection rates in low-income areas, and the persistence of cases in populations with veterinary access, suggest gaps in preventive governance. A cross-sectional survey was conducted in two high-challenge areas of metropolitan Rio de Janeiro, Brazil, from June 2023 to January 2024. Dogs older than 1 year and not on heartworm prophylaxis during the previous 6 months were enrolled. Blood samples were tested for D. immitis antigen, and owner questionnaires captured demographic, environmental and clinical data. Risk factors were evaluated using binomial regression models. Among 526 dogs sampled, the overall antigen-positive rate was 22.6%, with a higher prevalence in Niterói-Maricá (27.0%) than in the Western area of the Rio de Janeiro municipality (18.15%). Male, short-coated, heavier or outdoor-living dogs had significantly higher odds of infection. Coughing was more frequent in antigen-positive dogs, while no significant associations with weight loss or lethargy were observed. Despite widespread veterinary recommendations, substantial infection rates persist, especially in low-income communities, underscoring failures in preventive governance. Integrated efforts from veterinarians, regulatory authorities and the animal-health industry are urgently needed to improve chemoprophylaxis uptake and protect canine health in endemic regions.
Abstract The white-eared opossum Didelphis albiventris is widely distributed throughout Brazil and hosts several parasite species. This study aimed to analyze the influence of intrinsic (sex and age of hosts) and extrinsic (locality and type of land use) factors on the helminth communities of the white-eared opossum in areas of the Atlantic Forest. Helminth samples from 93 D. albiventris specimens from six different localities were used: Belo Horizonte, MG; Curitiba and Guaíra, PR; Porto Alegre, RS; and Mamanguape and Santa Rita, PB. Fourteen species of helminths were identified: Aspidodera raillieti, Cruzia tentaculata, Turgida turgida, Viannaia hamata, Rhopalias coronatus, Rhopalias horridus, Duboisiella proloba, Travassostrongylus orloffi, Travassostrongylus sextus, Brachylaima advena, Plagiorchis didelphidis, Trichuris minuta, Trichuris didelphis, and Oligacanthorhynchus microcephalus. Female hosts and adult hosts had greater helminth species richness and abundance. The helminth species richness and abundance in D. albiventris were influenced by intrinsic (sex and age of the host) and extrinsic (locality and land use) factors with the locality being the main determinant. The structure of the helminth infracommunities varied spatially, with greater differences with increasing geographic distance, highlighting the complexity of host‒parasite interactions in wildlife.
Abstract The aim of this study was to determine the prevalence and diversity of Eimeria spp. in commercial broiler chicken farms (CBCFs) across 20 municipalities in northwestern São Paulo State, Brazil. Eighty-eight fecal samples corresponding to 88 commercial broiler farms were examined by microscopic screening for Eimeria spp. oocysts. All positive samples were subjected to genus-specific nested PCR (18S rRNA gene) followed by next-generation sequencing to identify the Eimeria spp. Microscopy detected Eimeria spp. oocysts in 100% (88/88) of the samples. Next-generation sequencing revealed the following order of prevalence of Eimeria spp. sequences: Eimeria maxima: 83/88 (94.3%; CI: (87.4–97.6); Eimeria acervulina: 75/88 (85.2%; CI: 76.4–91.2); Eimeria necatrix/tenella: 19/88 (21.6%; CI: 14.3–31.3); Eimeria praecox: 19/88 (21.6%; CI: 14.3–31.3); and Eimeria mitis/mivati: 10/88 (11.4%; CI: 6.3–19.7). No sequences corresponding to Eimeria brunetti, Eimeria lata, Eimeria nagambie, and Eimeria zaria were detected. In conclusion, the highest prevalences were observed for E. maxima and E. acervulina, whereas E. tenella/necatrix, E. mitis/mivati, and E. praecox showed lower prevalences. Eimeria brunetti, E. lata, E. nagambie, and E. zaria were not detected in CBCFs from northwestern São Paulo State.
Abstract In Brazil, the species Amblyomma dissimile occurs mainly in the North and Midwestern regions and does not naturally occur in the Southern region. Here, we report the second introduction of this tick in Rio Grande do Sul, resulting from the translocation of its host, Caiman yacare (pantanal alligator), from the state of Mato Grosso to Gramado (RS), which highlights the risks associated with transporting wild animals between regions with different climates.
This study aimed to assess soil contamination with Ancylostoma spp. eggs in public parks and playgrounds in Hue City. A total of 240 soil samples were collected from 60 public parks and playgrounds located in two urban zones (central urban and peri-urban areas) during both the rainy and dry seasons. Ancylostoma spp. eggs were detected at 48 of 60 sampling sites (80%). The proportion of contaminated sites was significantly higher in central urban areas compared with peri-urban areas and during the rainy season compared with the dry season. In contrast, no significant differences were observed between sampling locations within individual parks, including areas near garbage bins and playground areas. Most positive sites showed low contamination intensity, with 1-4 eggs per 200 g of soil. Conventional PCR confirmed the presence of Ancylostoma caninum DNA in positive soil samples, indicating that dogs are the primary source of environmental contamination. These findings provide baseline data on soil-transmitted hookworm contamination in Hue City and highlight the need for improved dog faeces management, ecological sanitation, and public health education to reduce the risk of community exposure.
Abstract Coastal lagoons are among the most productive aquatic ecosystems worldwide and are widely used by mugilid fishes. Mugil liza stands out as one of the main resources of lagoon fisheries in southern and southeastern Brazil. This study aimed to identify the species composing the ectoparasite fauna of M. liza from the Maricá Lagoon, Rio de Janeiro State, Brazil. A total of 44 specimens of M. liza were examined, of which 95.4% were parasitized by at least one ectoparasite species. Six ectoparasite species were recorded. The copepod Ergasilus caraguatatubensis was the most representative species, with prevalence (P) of 86.4%, followed by the copepods Bomolochus nitidus (P = 43.2%), Caligus sp. (P = 2.3%) and Naobranchia lizae (P = 2.3%). The polyopisthocotylan Metamicrocotyla macracantha showed prevalence of 18.2% and the myxozoan Myxobolus episquamalis presented a low prevalence (P = 2.3%). The ectoparasite fauna of M. liza exhibited diversity, comprising six distinct families, highlighting the host's gills as an important site for parasite diversity. The results expand the environmental distribution of E. caraguatatubensis, B. nitidus, Caligus sp., N. lizae and M. macracantha within Rio de Janeiro State, increasing the known occurrence sites of these parasites, including lagoon.
African pygmy hedgehogs (Atelerix albiventris) are omnivorous mammals native to sub-Saharan Africa and popular exotic pets worldwide. Although their trade is illegal, it remains common in Brazil. Therefore, the aims of this study were to investigate the health status of hedgehogs from illegal breeding sites, through hematological, biochemical and fecal analyses, skin pathogen screening and molecular assays for hemotropic Mycoplasma spp. and tick-borne pathogens. Real-time PCR assays for hemotropic Mycoplasma spp. (16S rRNA) and conventional PCR assays for Theileria/Babesia spp. (18S rRNA) and Ehrlichia/Anaplasma spp. (16S rRNA) were applied. No ectoparasites were found at the time of sampling, and hematological and biochemical results indicated a good health status. Candida tropicalis (15/25, 60%), Mucor spp. (12/25, 48%), and Proteus vulgaris (10/25, 40%) were identified in fecal analysis. Skin's microbiological examinations revealed Staphylococcus spp. (25/25 - 100%) and Streptococcus spp. (13/25 - 52%). All samples tested negative for hemotropic Mycoplasma spp., Theileria/Babesia spp., and Ehrlichia/Anaplasma spp. These findings suggest that the evaluated animals were not infected with harmful pathogens. Understanding their potential role in zoonotic diseases is necessary, particularly in the context of exotic species.
Coinfection with Trypanosoma evansi and Hepatozoon felis represents a rare occurrence in wild felids, with no previous reports in Panthera onca. A free-ranging adult male jaguar weighing approximately 70 kg was examined after being rescued from wildfires in the Brazilian Pantanal (Corumbá, Mato Grosso do Sul). The initial hematological evaluation (D0) revealed mild anemia (PCV: 27.7%; reference: 30-45%), with Trypanosoma spp. trypomastigotes forms detected by direct microscopy. Treatment with diminazene aceturate (3.5 mg/kg, IM) was instituted on D1. On D5, microscopy revealed Hepatozoon felis gamonts within leukocytes, characterizing coinfection. Molecular analysis by PCR confirmed the presence of both agents in the D0 sample, with amplification products of approximately 600 bp (Hepatozoon spp.) and 196 bp (T. evansi), validating the microscopic diagnosis. Despite treatment and the absence of microscopically detectable parasitemia on D12, anemia persisted (PCV: 21.7%). The animal progressed to death on D19 during sedation for wound management. At necropsy, severe pulmonary involvement (bronchiolitis, alveolitis, and endogenous lipid pneumonia) compatible with smoke inhalation injury was observed. These findings highlight the importance of integrating hemoparasite surveillance into rehabilitation and conservation protocols for threatened felids in fire-affected ecosystems.
This study evaluated prevalence, productive losses, and spatial distribution of cases in cattle slaughtered under the Federal Inspection Service (SIF) in Minas Gerais (2021-2022). A total of 297,802 animals were inspected; cysticercosis was detected in 0.44% (531/120,011) of cattle in 2021 and 0.24% (419/177,791) in 2022. Detection led to immediate condemnation of viscera, reducing carcass value by about 10%, and to conditional utilization of 37.1% (352/950) of carcasses by chilling and 15.8% (150/950) by heat treatment, with value reductions of 30% and 70%, respectively. Cysticerci were mainly located in the heart (45.2%), liver (40.1%), and head (21.2%), with rare occurrences in the tongue, diaphragm, and lungs. Estimated losses over two years exceeded R$ 900,000, likely underestimated given that SIF slaughter often supplies export markets. Spatial distribution analysis showed a higher concentration of positive animals originating from the municipalities of Nanuque, Governador Valadares, and Carlos Chagas. Despite the relatively low prevalence, the spatial concentration of cases and the observed distribution pattern suggest the influence of regional environmental factors in maintaining bovine cysticercosis transmission.
Spirocamallanus rarus (Travassos, Artigas & Pereira, 1928) is reported for the first time parasitizing the intestine of Propimelodus eigenmanni (Van der Stigchel, 1946) collected from the Parauaú River, in Breves municipality, Pará, Brazil. Using light and scanning electron microscopy, several morphological aspects of this species were clarified and expanded upon. Newly described features include details of the cephalic structures, cuticular topography, the number and distribution of the caudal papillae in males, and the morphology of the vulva, anus and the phasmids on the tail in females. In this study, S. rarus was redescribed based on these new observations and a supplemental morphological re-study of the holotype and voucher specimens deposited in the Helminthological Collection of the Oswaldo Cruz Institute.
This research aimed to quantify resistance levels to cypermethrin, chlorpyrifos, amitraz, ivermectin, and fipronil in Rhipicephalus microplus larvae from cattle farms in the Recôncavo baiano region of the State of Bahia, Brazil. We also identified associations between resistance level and operational factors. Engorged adult female ticks were collected from 14 farms to perform bioassays for the five acaricide classes and determine the intensity of resistance. A nonparametric Mann-Whitney U test was employed to identify categorical factors associated with resistance intensities. A high frequency of resistance was observed across all five compounds evaluated, even on farms that reported never using these products. On all farms, we found tick populations resistant to at least three acaricides. While cypermethrin, chlorpyrifos, and ivermectin showed the highest intensity of resistance (RR50: 38.06, 126, and 27.35, respectively), amitraz and fipronil showed the lowest (RR50: 11.28 and 1.06, respectively). In the Recôncavo baiano region, the incorporation of amitraz and fipronil in the formulation of strategic control protocols is recommended.
The Anaplasmataceae family comprises vector-borne alpha-proteobacteria with significant impact on animal and human health. In Brazil, the diversity and circulation of these agents in wild mammals require further exploration. This study investigated the presence of Anaplasmataceae agents in wild mammals, and ticks from Goiás state, in midwestern Brazil. A total of 97 blood samples, 22 tissue samples, and 69 ticks from 18 mammalian species were analyzed. Conventional PCR targeting the 16S rRNA gene revealed Anaplasmataceae DNA in 11.3% (11/97) of blood samples, 13.6% (3/22) in tissue samples and 2.9% (2/69) of tick specimens. Positive hosts included Subulo gouazoubira, Hydrochoerus hydrochaeris, Cerdocyon thous, Chrysocyon brachyurus, Tapirus terrestris, and Myrmecophaga tridactyla, as well as two Amblyomma sculptum ticks. Phylogenetic analysis based on the 16S rRNA gene from Anaplasma sp. detected in S. gouazoubira clustered with "Candidatus Anaplasma boleense", while 23S-5S rRNA (intergenic spacer) ITS supported a potentially undescribed Anaplasmataceae agent. A short 16S rRNA gene fragment showing high identity with "Ca. Anaplasma boleense" was detected in H. hydrochaeris for the first time. These findings expand current knowledge on the diversity and host range of Anaplasmataceae in Brazil, highlighting the role of wild mammals in maintaining these bacteria in Goiás state, midwestern Brazil.
Abstract Ticks are ectoparasites of major public and veterinary health importance, and identifying their vertebrate hosts is crucial for recognizing pathogen reservoirs. This study investigated tick–wild mammal associations in two areas of the Brazilian Amazon. Between 2021 and 2023, wild mammals were captured using Tomahawk® and Sherman® traps, and ticks were collected manually or with forceps. A total of 110 wild mammals were captured, including 66 marsupials, 43 rodents, and one felid, representing 12 genera. Three species were identified at the species level: Didelphis marsupialis, Myoprocta pratti, and Leopardus pardalis. Tick infestation was recorded in 37.3% of the animals, with 262 ticks collected. The identified tick species were Amblyomma coelebs, Amblyomma ovale, Amblyomma latepunctatum, Amblyomma scalpturatum, Amblyomma pacae, and Haemaphysalis sp. These findings expand knowledge of tick–host associations involving wild mammals in the Brazilian Amazon.
Gastrointestinal nematode (GIN) infections significantly impact the health of ruminants. The indiscriminate use of anthelmintics contributes to the selection of drug-resistant parasites. Compounds containing selenium (Se) and tellurium (Te) have emerged as promising alternatives. This study aimed to evaluate the anthelmintic activity of diphenyl diselenide (PhSe)2, phenylselenenyl chloride (4-Cl-PhSe)2, and ammonium trichloro (dioxoethylene-O,O') tellurate (AS-101) on eggs and larvae (L3) of GIN. The compounds were tested using egg-hatch and larval-migration inhibition tests. Additionally, the possible in vitro cytotoxic effects were evaluated using the AlamarBlue assay. (PhSe)2 exhibited the highest ovicidal effect, with a 50% inhibitory concentration (IC50) of 1.801 mmol L-1 for GIN isolated from sheep and 1.845 mmol L-1 for GIN from cattle. AS-101 showed the highest larvicidal activity, with IC50 values of 0.976 mmol L-1 for GIN of sheep and 1.035 mmol L-1 for GIN of cattle. Combinations of (PhSe)2 with ivermectin (IVM) showed a mild synergistic effect, with an additive interaction of 13.33%. Among the tested compounds, (PhSe)2 showed the lowest cytotoxicity in LLC-MK2 cells. Taken together, these data highlight the therapeutic potential of the novel molecules.
Abstract Felines are susceptible toLeishmaniaspp. infection in endemic areas; however, histopathological studies on the organs of infected felines remain scarce. This study evaluated the inflammatory response and cutaneous parasitism in 13 naturally infected felines in Teresina, Piauí, Brazil. After diagnosis, the animals were euthanized, and skin fragments from the face, external ear, periocular region, muzzle, and dorsum were histopathologically analyzed. The cytology of the ear skin revealed amastigote forms ofLeishmaniaspp. in 84.62% of the felines, with this region being the most parasitized. The inflammatory infiltrate was mild-to-moderate in 38.5%, with a diffuse distribution in 77% of cases. Mononuclear cells predominated in 92%, while polymorphonuclear cells were rare (8%). Amastigote forms were discrete in 46%, and 46% presented with granulomatous dermatitis. The main epidermal changes were exocytosis (92.5%), acanthosis, and spongiosis (61.5%). These findings highlight the importance of histopathology as a diagnostic tool and contribute to the understanding of the pathogenesis of feline leishmaniasis, aiding in the development of diagnostic and therapeutic research.
Reptiles of the order Squamata are commonly parasitized by ticks in the family Ixodidae. However, they can also host argasid ticks of the genus Ornithodoros. In this study, we reported Ornithodoros rietcorreai parasitizing a Boa constrictor and a human in Caatinga Zoobotanical Park, within the 72nd Caatinga Infantry Battalion of the Brazilian Army in Petrolina, Pernambuco (PE). Thirty argasid tick specimens, including two larvae, 17 nymphs, four females, and seven males, were removed from the body surface of the snake. Substantial environmental infestations were observed within the snake enclosure, with ticks in the soil, beneath rocks, and on wood. In total, 126 tick specimens comprising 70 larvae, 13 nymphs, 17 females, and 26 males were collected from the environment. During the sampling process, a team member that was parasitized by larvae developed edema, erythema, and pruritus, at the bite sites after 24 h. To our knowledge, this is the first study to report parasitism by O. rietcorreai in a captive Boa constrictor in Brazil, along with a case of human parasitism within a snake enclosure.
Canine demodicosis is a cutaneous parasitic disease caused by excessive proliferation of mites of the genus Demodex. This study reports a case of localized demodicosis associated with a concurrent infestation by Demodex canis and Demodex cornei in an adult mixed-breed female dog from the state of Coahuila, northern Mexico. The animal presented two focal alopecic lesions in the nasal and perioral regions, with no evidence of secondary infection. Deep skin scrapings were collected and examined by light microscopy. Species-level identification was based on diagnostic morphological characters, including opisthosomal shape and proportions, supracoxal spine morphology, and pharyngeal bulb structure, confirming the simultaneous presence of both species. This study represents the first confirmed record of D. canis and D. cornei in domestic dogs from the state of Coahuila and contributes to the knowledge of geographic distribution and diversity of demodecid mites in Mexico.
