Patrick Mathews Delgado

• Associate Researcher
• Associate Researcher at São Paulo State University

Smart nanocarrier-based bioactive delivery systems are a current focus in nanomedicine for allowing and boosting diverse disease treatments. In this context, the design of hybrid lipid-polymer particles can provide structure-sensitive features for tailored, triggered, and stimuli-responsive devices. In this work, we introduce hybrid cubosomes that...

Branchiura are a crustacean parasite widely known around the world as fish lice. In South America, they have been most studied in Brazil as with high levels of infestation, the parasites can be harmful to the health of fish and cause economic losses in fish farms. The objective of the present study is to provide, for the first time, significant inf...

Herein, a detailed molecular phylogeny analysis was developed to determine the phylogenetic position of a new freshwater histozoic myxosporean cnidarian, Henneguya markiana sp. nov. from the world’s largest tropical wetland area, Pantanal, Brazil. The new species is described using an integrative taxonomy approach including morphology, biological t...

Nanovesicles produced with lipids and polymers are promising devices for drug and bioactive delivery and are of great interest in pharmaceutical applications. These nanovesicles can be engineered for improvement in bioavailability, patient compliance or to provide modified release or enhanced delivery. However, their applicability strongly depends...

This study results from a continued investigation of the occurrence and diversity of parasites of freshwater fish in the Solomon Islands. Thus, we revealed a new host as well as a new site of infection and a new geographical area for the cryptogonimid parasite, Stemmatostoma cribbi (Digenea: Cryptogonimidae). The cryptogonimid species was identifie...

In this study, a Henneguya myxosporean species is described to infect an ecological, biological, and evolutionary important fish from Amazon biome. The myxosporean was found in the skin of only one specimen of marbled swamp eel, Synbranchus marmoratus caught in a small stream from Peruvian Amazon floodplain. Mature myxospores have ovoid shape from...

The upsurge of bacterial resistance to conventional antibiotics turned a well-recognized public health threat. The need of developing new biomaterials of effective practical use in order to tackle bacterial resistance became urgent. In this study, a submicrometric bioparticle of known antibacterial activity was produced in powder form with suitable...

In recent decades, the pharmaceutical industry has shown great interest in new products for drug delivery, since studies with drug nanocarriers have evidenced the application potential of these systems. A relatively new strategy for nano-drug delivery is the use of cubosome, which is a nanoparticle with crystalline structure formed by a lipid bilay...

Nano-structured and functionalized materials for encapsulation, transport, targeting and controlled release of drugs are of high interest to overcome low bioavailability in oral administration. We develop lipid-based cubosomes, which are surface-functionalized with biocompatible chitosan-N-arginine and alginate, and displaying internal liquid cryst...

The development of biomaterials to enable application of antimicrobial peptides represents a strategy of high and current interest. In this study, a bioparticle was produced by the complexation between an antimicrobial polypeptide and the biocompatible and biodegradable polysaccharides chitosan-N-arginine and alginate, giving rise to a colloidal po...

Myxozoans are a diverse group of parasitic cnidarians of wide distribution. A new species, Myxobolus matogrossoensis n. sp., is herein described infecting wild specimens of tetra mato-grosso Hyphessobrycon eques, caught in the Pantanal biome, the world’s largest tropical wetland area. Cysts were found in 3 of the 30 examined fishes. Mature myxospor...

Myxosporeans are a diverse group of microscopic cnidarians of wide distribution that evolved into a parasitic lifestyle. A new myxosporean species, Myxobolus sp., is herein described infecting the mandible of wild specimens of Synbranchus marmoratus, caught in the world's largest tropical wetland area, Pantanal, Brazil. Light, scanning, transmissio...

This study investigated the in vitro efficacy of the essential oil of Minthostachys mollis, Origanum vulgare, and Salvia rosmarinus against monogeneans from the gills of Piaractus brachypomus and the tolerance of this fish to these oils. In vitro concentrations of M. mollis (80, 200, 400, 600, 800, and 1000 mg L⁻¹), O. vulgare, S. rosmarinus (80, 2...

Surface modified cubosomes were produced by complexation with biopolymers providing polyelectrolyte shells. The pH-sensitive characteristics of the obtained nanocomplexes can be profitable for drug delivery purposes in the intestinal tract.

We report a strategy for sustainable development of pH-responsive cubic liquid crystalline nanoparticles (cubosomes), in which the structure-defining lyotropic nonlamellar lipid and the eventually encapsulated guest molecules can be protected by pH-sensitive polyelectrolyte shells with mucoadhesive properties. Bulk non-lamellar phases as well as pH...

Parasite infections in fish require constant surveillance and strategies for efficient treatments which guarantee the fish health, their sale value and the non-propagation of pathogens in new environments. Fish treatments based on nanotechnology become of increasing interest since nanoparticles have been shown as efficient materials for optimizing...

Myxosporeans are microscopic cnidarians associated with severe diseases in aquaculture and wild fish populations. This group of parasitic cnidarians thus warrants close attention concerning its potential impact on susceptible fish stocks. At present, little is known about this group of parasites infecting anguillid eels. From myxospore specimens co...

In this study, integrative taxonomy is applied to describe a new dactylogyrid species, Ameloblastella pirarara sp. n. from the gills of Phractocephalus hemioliopterus, a commercially and ecologically important Amazonian catfish. Ameloblastella pirarara sp. n. can be distinguished from its congeners mainly by the morphology of the male copulatory or...

Ceratomyxa amazonensis is a cnidarian myxosporean originally described with strongly arcuate crescent-shaped myxospores, absence of vegetative stages and infecting Symphysodon discus , an important Amazonian ornamental fish in the aquarium industry. As part of a long-term investigation concerning myxosporeans that infect discus fish Symphysodon spp...

Ceratomyxa amazonensis is a cnidarian myxosporean originally described with strongly arcuate crescent-shaped myxospores, absence of vegetative stages and infecting Symphysodon discus, an important Amazonian ornamental fish in the aquarium industry. As part of a long-term investigation concerning myxosporeans that infect discus fish Symphysodon spp....

The farmed red-bellied pacu Piaractus brachypomus is a valuative commercial fish widely exploited in fish farming. Histopathologic alterations in small intestine of this fish were associated with heavy roundworms infection. Of a total of thirty-five fish examined, all were parasitized with a prevalence of 100%, intensity of 290–6403, and mean inten...

Cichla monoculus (Spix & Agassiz, 1831) es una especie con gran potencial para su crianza en ambientes controlados en la Amazonía Peruana, hecho que ha llevado a su producción semi-intensiva e intensiva destinada al consumo humano. Sin embargo, se necesitan más estudios sobre la población de parásitos que afectan la producción y desarrollo de la es...

La infección por anquilostomas se ha convertido en una amenaza cada vez más grave para la salud pública en los indígenas de Brasil. La detección y casos clínicos de anquilostomas se han informado en el pasado; sin embargo, no se sabe nada acerca de la ocurrencia entre los indígenas Tapirapé en el Brasil. El objetivo de este estudio fue determinar l...

A new cnidarian myxosporean infecting the spleen of an economic and ecological important bryconid fish (Salminus franciscanus) is described based on integrative taxonomic approach including morphological, ultrastructural, biological traits, geography, molecular data and phylogenetic analysis. In a total of thirty specimens examined, nineteen (63.3%...

The FDA-approved drug ivermectin is applied for treatments of onchocerciasis and lymphatic filariasis. The anti-cancer and anti-viral activities have been demonstrated stressing possibilities for the drug repurposing and therefore new information on high dosage safety is on demand. We analyzed in vivo tissue responses for high doses of ivermectin u...

A new myxozoan species belonging to the genus Henneguya was isolated from the serous membrane of the visceral cavity of the hognosed catfish Brochis multiradiatus from Peruvian Amazon. Whitish plasmodia, macroscopically visible, were found in four of the thirty examined fishes. Mature myxospores were ellipsoidal in shape in frontal view and had a t...

A new Myxobolus species is described infecting gill filaments of the endangered ornamental fish Otocinclus cocama from Peruvian Amazon. In a total of 35 fish examined, five (14.3%) had myxozoan plasmodia. Taxonomic analysis was performed integrating multiple characters, including morphometrical, biological traits, ssrDNA sequence data and host ecol...

Nanostructure bicontinuous cubic phase self-assembled materials are receiving expanding applications as biocompatible delivery systems in various therapeutic fields. The functionalization of cubosome, spongosome, hexosome and liposome nanocarriers by pH-sensitive lipids and/or pH-sensitive polymer shells offers new opportunities for oral and topica...

In order to make more efficient chitosan-based nanoparticles for transfection in physiological condition, chitosomes composed of chitosan modified with arginine and complexed with DOTAP/DOPE lipids are synthesized (named chitosomes) by reverse phase evaporation technique. Structure analyses of chitosomes with or without plasmid DNA (pDNA) are perfo...

This study investigated the in vitro and in vivo anthelminthic efficacy, histopathological and hematological effects of Cymbopogon citratus essential oil (EO) in Colossoma macropomum. The major compounds of the essential oil were geranial (45.7%) and neral (33.9%). Essential oil was assayed at concentrations of 100, 200, 300, 400 and 500 mg L⁻¹ for...

This study compared the in vitro anthelmintic activity of Copaifera reticulata oleoresin (200, 400, 600, 800 and 1,000 mg/L) and of nanoemulsions prepared with this oleoresin (50, 100, 150, 200 and 250 mg/L) against monogeneans on the gills of Colossoma macropomum. The major compounds present in the oleoresin of C. reticulata were γ‐macrocarpene (1...

A new microscopic cnidarian is described, infecting five of thirty (16.6%) specimens of Corydoras schwartzi caught in the Purus River, State of Amazonas, Brazil. Histological analysis showed that cyst development occurred in the serosa layer of the intestine. Mature myxospores are ovoid in body shape in frontal view, 22.4 ± 0.3 μm in total length a...

The production of efficient micro and nanoparticles of pH-responsive and mucoadhesive properties is of high scrutiny. We produced a drug carrier bioparticle providing such structural features. Thereby, protonated chitosan bearing chemically bonded arginine was interacted with ionized alginate, leading to the assembling of colloidal particles of spe...

We describe the histopathological damage caused by parasite infection in farmed specimens of matrinxã Brycon cephalus, an economic important fish for aquaculture in the Amazon region. The fish were collected from an extensive fish farm, nearby the city of Nauta, Department of Loreto, Peru. Parasitic nematodes were found infecting the small intestin...

Myleus schomburgkii Jandine & Schomburgk, 1841 is a fish species distributed in regions of South America. It has great economic importance for the exports generated as ornamental fish. However, little is known about the presence of monogeneans in this fish. The aim of this study was to investigate the monogenean parasites in farmed M. schomburgkii...

Materials for Biomedical Engineering: Nanomaterials-Based Drug Delivery highlights the progress made in the field of nanostructures bioactive materials and their impact on efficient drug delivery towards personalized medicine. Drug delivery is a well investigated and challenging bio-medical field, with promising perspectives in medicine and enginee...

Myxosporean are endoparasitic cnidarians of wide distribution and responsible for important economic losses in fisheries and aquaculture. A new myxosporean species, Henneguya peruviensis n. sp., is herein described as obtained from the gill filaments of Hyphessobrycon loretoensis caught in the Nanay River, Department of Loreto, Peru. The parasite w...

Molecular data of Henneguya chydadea Barassa, Cordeiro and Arana, 2003, found in the gill filaments of Astyanax lacustris bred in fish farm in the State of Mato Grosso do Sul, Brazil was obtained in order to estimate their phylogenetic position among other platysporines myxosporean. The prevalence of the parasite was 28.1% and the range intensity w...

In this study, a new host record for Dadaytrema oxycephala (Digenea: Cladorchiidae) is described from an important Amazonian ornamental fish. The parasite was identified based in the general morphology and surface ultrastructure of the young and mature trematodes using scanning electronmicroscopy. The digenetic trematodeswere found in the intestine...

The use of liposomes and polyelectrolytes is on scientific and technologic scrutiny for development of gene nano carriers. We produced a reverse phase lipid:chitosan “chitosome” to which plasmid DNA (pDNA) effectively interacts and compacts. Dynamic light scattering and zeta potential evidence the complexation between pDNA and lipid:chitosan partic...

Biomaterials conceived for vectorization of bioactives are currently considered for biomedical, biological and environmental applications. We have produced a pH sensitive biomaterial composed of natural source alginate and chitosan polysaccharides for application as drug delivery system via oral administration. The composite particles preparation w...

The occurrence of copepods ergasilid was investigated in two species of cichlids of economic importance for aquaculture in the Amazon region: Cichla monoculus and Chaetobranchus semifasciatus. The fish were collected from a semi-intensive fish farm, near the city of Nauta, Loreto State, Peru. Copepods were found in the gill filaments of 44 of 85 sp...

A new species of Myxosporea, Henneguya loreotoensis n. sp. is described parasitizing the gill filaments from 17 of 35 specimens (48.5%) of Corydoras leucomelas (Siluriformes: Callichthyidae) caught in the Nanay River, near village Ninarumi, in the Loreto state, Peru. Mature spores were ellipsoidal in shape from the frontal view, measuring 36.2 ± 0....

Biodegradable microparticles for oral delivery of antiparasitic drugs in ornamental fish Patrick D. Mathews, Gabriella S. Gama, Ana C.M. Fernandes-Patta, Omar Mertins The global business of aquarium fish involves the trade of about 400 million specimens per year. In Brazil, the majority of these fish are extracted from the Amazon River and its trib...

Interest in the Myxozoa as significant fish parasites is still increasing with the growing importance of fish farm and wild fisheries around the world. However, little is known about these parasites in South American ornamental fishes, particularly those from the Amazon, where there is a diverse assemblage of several hundred species of live fish. T...

A new myxosporean species, Myxidium peruviensis n. sp., is described parasitizing the gall bladder of the yellow-spotted river turtle Podocnemis unifilis kept in captivity in an Amazonian Peruvian turtle rescue unit in the city of Iquitos, State of Loreto, Peru. The parasite was found in four of ten (40%) P. unifilis examined. The new species was c...

Bicontinuous cubic phases were produced with introduction of chitosan in phospholipid/water hydrogel, providing composites of defined molecular organization. The ratio of lipid/water was constant and swelling of lipids bilayer is delimited by incorporation of polymer molecules into the structure. By means of synchrotron small angle X-ray scattering...

This study reports, for the first time, a myxosporan species of the genus Myxidium in a Neotropical turtle. Myxidium turturibus n. sp., was found in the gall bladder of Podocnemis expansa (Testudines: Podocnemididae) farmed in Brazilian Amazon. Numerous disporic pseudoplasmodia in different developmental stages, and mature spores were free in the b...

The presence of Notozothecium bethae was investigated in 76 black band myleus (Myleus schomburgkii [Actinopterygii: Charasiformes]) born and kept in captivity in two semi-intensive breeding cages in the northern region of Peru. Among the 76 cultivated specimens of M. schomburgkii examined in the present study, 100 % had monogenean on the gill and t...

The specious genus Ceratomyxa Thélodan, 1892, infect mainly gallbladder of marine fishes, with only five species reported infecting species from freshwater environment. This study performed morphological and phylogenetic analyses involving a new Ceratomyxa species (Ceratomyxa amazonensis n. sp.) found in gallbladder of Symphysodon discus Heckel, 18...

A new species of myxozoan, Henneguya melini sp. n. (Myxosporea: Myxobolidae), was described based on morphologic and ultrastructural features. This is a parasite of the ornamental freshwater fish C. melini from the Rio Negro, and it was found in five of 30 (16.7 %) C. melini examined. The parasite was found in the gill filaments, and the plasmodia...

tMyxobolus niger n. sp. (Myxozoa) is described in the connective tissue of the serosa layer of the gill arch ofCorydoras melini (Callichthyidae) captured from the Negro River, Amazonas State, Brazil. The prevalenceof the parasite was 20% and the range intensity was 1–2 cysts per fish. The plasmodia were white andspherical to ellipsoidal, measuring...

In a survey of myxozoan parasites of ornamental freshwater fish from the Rio Negro river, it was found that seven of 30 (23.3 %) Corydoras melini specimens examined had plasmodia of a new Myxidium species (Myxidium amazonense n. sp.) in the gallbladder. The fish were caught in the Rio Negro river, in the municipality of Santa Isabel do Rio Negro, i...

##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

The Amazonian manatee (Trichechus inunguis) is an aquatic mammal (Family Trichechidae) that inhabits freshwater environments. It is endemic to the Amazon Basin, and occurs from Marajó Island (at the mouth of the Amazon River in Brazil) to the headwaters of the floodplain in Colombia, Peru and Ecuador. It is exclusively aquatic and resides in calm w...

We have prepared a chitosan polymer modified with gallic acid in order to develop an efficient protection strategy of biological membranes against photodamage. Lipid bilayers were challenged with photoinduced damage by photosensitization with methylene blue, which usually causes formation of hydroperoxides, increasing area per lipid, and afterwards...

Importance of research on parasites in fish Patrick Mathews Delgado University of Campinas, Institute of Animal Biology, Department of Parasitology Overexploitation of wild fish population in the last years has greatly increased the importance of aquaculture as source of fish protein, besides their importance as an object of sport fishery and pe...

Closed environment and controlled irrigation techniques are conventionally used to root camu-camu stem cuttings. But development of other techniques of camu-camu propagation is required for smallholder growers in Peru, who cultivate camu-camu on restingas, old river levee fragments on the margins of white-water rivers. Additionally, the month in wh...

The aim of this study was to evaluate the presence of Dawestrema cycloancistrioides in semi-intensive fish farming of fingerlings of Arapaima gigas. Between September and November 2013, 60 individuals of A. gigas born in captivity, were collected in three concrete ponds, from a semi-intensive fish farm in the Peruvian Amazon. For the study of scler...

In the Peruvian Amazon, there is no information about hematological parameters of parasitized fish maintained in fish farms. In this study, the effects of parasitism by Anacanthorus spathulatus on hemoglobin (Hb), hematocrit (Ht), red blood cells (RBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin co...

Se colectaron 10 especímenes de paiche Arapaima gigas de un centro de cultivo piscícola semiintensivo de Maynas, Loreto, Perú, entre junio y octubre de 2011, para investigar la presencia de parásitos. Se identificó una alta infección de nematodos de la especie Nilomena senticosum. Se encontró una prevalencia de 100% y una intensidad media de 80 par...

Hookworms infection has become an increasingly serious threat to public health in Brazilian indigenous. Detection and/or clinical cases of hookworms have been reported in the past; however, nothing is known about the prevalence among indigenous Tapirapé in Brazil. We studied the presence of hookworms in indigenous Tapirapé ethnic group from county...

Strongyloides stercoralis is an intestinal helminth, which infects millions of people worldwide. In the present study, 542 individuals from six indigenous villages were enrolled of whom 24 (4.43 %) were positive for S. stercoralis based on analysis by microscopy of fecal concentrates. S. stercoralis was more prevalent in males (5.32 %, 14/263) than...

Strongyloides stercoralis is an intestinal helminth, which infects millions of people worldwide. In the present study, 542 individuals from six indigenous villages were enrolled of whom 24 (4.43 %) were positive for S. stercoralis based on analysis by microscopy of fecal concentrates. S. stercoralis was more prevalent in males (5.32 %, 14/263) than...

A total of 1528 stool samples were examined during a survey of intestinal parasites in 542 members of the Tapirapé ethnic group (279 females and 263 males), who live in the Brazilian Amazon region of Mato Grosso. Overall, 542 individuals from six indigenous villages were enrolled of whom 45 (8.3%) were positive for Hymenolepis nana based on analysi...

The present study aims to evaluate the monogenean infestation in Astronotus ocellatus bred in a fish farm in the Peruvian Amazon. Fifty individuals of the species A. ocellatus were collected between July and August 2011 from a semi-intensive fish farm, located in the northeast of the State of Loreto, Peru. This study identified a high infestation i...

Brycon cephalus Günther, 1869, (Characidae: Bryoconinae) represents a socio-economically important species in the Amazon basin and actually semi-intensive and intensive production for human consumption has emerged in the last years. Therefore, more studies are required in fish farming development, especially concerning the populations of parasites...

The paiche, Arapaima gigas represents a socio-economically important species in the Peruvian Amazon, and actually an intensive production for human consumption has emerged during the last years. Therefore, more studies are required in fish farming development, especially concerning populations of parasites that affect fish production yields. Eighty...

A high infestation of the monogenean Gussevia tucunarense in a cultivation of bujurqui-tucunare was reported. The prevalence was 100%. The mean intensity and abundance of the parasite was 164.4 of parasites per individual. This is the first report of a high infestation by G. tucunarense in C. semifasciatus cultured from the Peruvian Amazon.

The Amazonian manatee (Trichechus inunguis) is an aquatic mammal that inhabits freshwater environments and is endemic to the Amazon Basin. The presence of Toxoplasma gondii antibodies was investigated in 19 manatees in one rescue unit in the northern region of Peru. Antibodies to T. gondii were detected in 12 (63.2 %) of 19 animals by using the mod...

The Amazonian manatee (Trichechus inunguis) is an aquatic mammal that inhabits freshwater environments and is endemic to the Amazon Basin. The presence of Toxoplasma gondii antibodies was investigated in 19 manatees in one rescue unit in the northern region of Peru. Antibodies to T. gondii were detected in 12 (63.2 %) of 19 animals by using the mod...

The boquichico Prochilodus nigricans represents a socio-economically important species in the Amazon basin and semi-intensive and intensive production for human consumption has emerged in the last years. Three species of parasites were collected and identified: Rhinonastes pseudocapsaloideum, Trichodina sp. and Lecithobotrioides elongates. R. pseud...

Cichla monoculus (Spix & Agassiz, 1831) is a species with great potential for breeding in controlled environments in the Peruvian Amazon. This fact that has led to semi-intensive and intensive production intended for human consumption. However, more studies are required regarding the population of parasites that are affecting breeding and developme...

The presence of Toxoplasma gondii and Leptospira spp. antibodies was investigated in 74 manatees (Trichechus inunguis [Mammalia: Sirenia]) kept in captivity in two rescue units in the northern region of Brazil. Antibodies to T. gondii were detected in 29 (39.2%) of 74 animals by using the modified agglutination test (titer, 1:25). For antibodies ag...

The gamitana is a species of socio-economic importance in the Peruvian Amazon, often intensively produced locally for human consumption. Because of this, more studies concerning parasite populations affecting this species' culture are necessary. In this study, a heavy copepod infestation of Perulernaea gamitanae is reported in a managed culture of...