RESUMEN
The endoparasitic fauna of Acestrorhynchus lacustris from eight marginal lagoons of the upper and middle São Francisco river basin, Brazil, is recorded here for the first time. For this, a total of 106 specimens of A. lacustris were collected. Eighteen helminth species were found. The taxa recorded were phylum Platyhelminthes: one metacercaria of Clinostomum sp. (Trematoda: Clinostomidae) and plerocercoid larvae of unidentified species (Eucestoda: Proteocephalidae gen. sp.); phylum Acanthocephala: juvenile of Quadrigyrus sp.; and phylum Nematoda: larvae of Brevimulticaecum sp., Contracaecum sp. Type1, Contracaecum sp. Type2, Hysterothylacium sp., Gnathostoma sp., Spiroxys sp., juvenile and adult specimens of Freitascapillaria sp., Paracapillaria piscicola, Capillariidae gen. sp., Procamallanus (Spirocamallanus) hilarii, Procamallanus (S.) inopinatus, Procamallanus (S.) saofranciscencis, Travassosnema travassosi paranaensis, Cystidicoloides fischeri and Spinitectus rodolphiheringi. Proteocephalidae gen. sp., Contracaecum sp. Type1 and Travassosnema t. paranaensis were present in all eight lagoons with high parasitic indexes. Proteocephalidae gen. sp., Brevimulticaecum sp., Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii, C. fischeri and S. rodolphiheringi are new records for A. lacustris. The known geographical distribution of Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii and Travassosnema t. paranaensis has now been extended to the São Francisco river basin.(AU)
A fauna endoparasitária de Acestrorhynchus lacustris de oito lagoas marginais da bacia do alto e médio rio São Francisco, Brasil, foi registrada pela primeira vez. Para isso, um total de 106 espécimes de A. lacustris foi coletado. Dezoito espécies de helmintos foram encontradas. Os táxons relacionados foram do Filo Platyhelminthes: uma metacercária de Clinostomum sp. (Trematoda: Clinostomidae); larvas plerocercoides de espécie não identificada (Eucestoda: Proteocephalidae gen. sp.); Filo Acanthocephala: juvenil de Quadrigyrus sp.; e Filo Nematoda: larvas de Brevimulticaecum sp., Contracaecum sp. Tipo1, Contracaecum sp. Tipo2, Hysterothylacium sp., Gnathostoma sp., Spiroxys sp.; juvenis e adultos de Freitascapillaria sp., Paracapillaria piscicola, Capillariidae gen. sp., Procamallanus (Spirocamallanus) hilarii, Procamallanus (S.) inopinatus, Procamallanus (S.) saofranciscencis, Travassosnema travassosi paranaensis, Cystidicoloides fischeri e Spinitectus rodolphiheringi. Proteocephalidae gen. sp., Contracaecum sp. Tipo1 e Travassosnema t. paranaensis foram compartilhadas entre todas as oito lagoas com altos índices parasitários. Proteocephalidae gen. sp., Brevimulticaecum sp., Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii, C. fischeri e S. rodolphiheringi são novos registros para A. lacustris. Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii e Travassosnema t. paranaensis têm sua distribuição geográfica estendida para a bacia do rio São Francisco.(AU)
Asunto(s)
Trematodos/clasificación , Characiformes/parasitología , Helmintos/clasificación , Parasitología , Brasil , Estanques/parasitologíaRESUMEN
BACKGROUND: Larvicides are typically applied to fixed and findable mosquito breeding sites, such as fish farming ponds used in commercial aquaculture, to kill immature forms and thereby reduce the size of adult malaria vector populations. However, there is little evidence suggesting that larviciding may suppress community-wide malaria transmission outside Africa. Here, we tested whether the biological larvicide VectoMax FG applied at monthly intervals to fish farming ponds can reduce malaria incidence in Amazonian Brazil. METHODS: This study was carried out in Vila Assis Brasil (VAB; population 1700), a peri-urban malaria hotspot in northwestern Brazil with a baseline annual parasite incidence of 553 malaria cases per 1000 inhabitants. The intervention consisted of monthly treatments with 20 kg/ha of VectoMax FG of all water-filled fish ponds in VAB (n ranging between 167 and 170) with a surface area between 20 and 8000 m2, using knapsack power mistblowers. We used single-group interrupted time-series analysis to compare monthly larval density measurements in fish ponds during a 14-month pre-intervention period (September 2017-October 2018), with measurements made during November 2018-October 2019 and shortly after the 12-month intervention (November 2019). We used interrupted time-series analysis with a comparison group to contrast the malaria incidence trends in VAB and nearby nonintervention localities before and during the intervention. RESULTS: Average larval densities decreased tenfold in treated fish farming ponds, from 0.467 (95% confidence interval [CI], 0.444-0.490) anopheline larvae per dip pre-intervention (September 2017-October 2018) to 0.046 (95% CI, 0.041-0.051) larvae per dip during (November 2018-October 2019) and shortly after the intervention (November 2019). Average malaria incidence rates decreased by 0.08 (95% CI, 0.04-0.11) cases per 100 person-months (P < 0.0001) during the intervention in VAB and remained nearly unchanged in comparison localities. We estimate that the intervention averted 24.5 (95% CI, 6.2-42.8) malaria cases in VAB between January and December 2019. CONCLUSIONS: Regular larviciding is associated with a dramatic decrease in larval density and a modest but significant decrease in community-wide malaria incidence. Larviciding may provide a valuable complementary vector control strategy in commercial aquaculture settings across the Amazon.
Asunto(s)
Anopheles/efectos de los fármacos , Acuicultura/métodos , Insecticidas/farmacología , Larva/efectos de los fármacos , Malaria/prevención & control , Control de Mosquitos/métodos , Mosquitos Vectores/efectos de los fármacos , Animales , Anopheles/parasitología , Brasil/epidemiología , Explotaciones Pesqueras , Humanos , Incidencia , Malaria/epidemiología , Malaria/transmisión , Mosquitos Vectores/parasitología , Estanques/parasitología , Factores de TiempoRESUMEN
Degradation and habitat loss of natural grasslands in Southern Brazil has a negative impact on native organisms, potentially including the composition of anuran helminth communities. Here, we characterized the richness, abundance, taxonomic composition, prevalence and intensity of helminth infection in four anuran species. Host anurans were collected in 34 ponds (19 in native grasslands with livestock and 15 in agricultural cultivation) from the highland grasslands in the Brazilian states of Santa Catarina and Paraná. Our results showed a significant difference between native grasslands with livestock and agricultural cultivation regarding the structure of helminth communities for the hosts Aplastodiscus perviridis and Pseudis cardosoi. We also found a greater prevalence and intensity of infection in anurans in areas of agricultural cultivation than in native grasslands with livestock. We found that the environmental descriptors (local and landscape) seem to explain most of the differences in anuran parasitism recorded between native grasslands with livestock and agricultural areas. Thus, we emphasized that the loss of grassy habitat due to conversion to agricultural cultivation can alter helminth communities in anurans, with further work needed to understand the mechanisms involved.
Asunto(s)
Anuros/parasitología , Helmintos , Agricultura , Animales , Biodiversidad , Brasil , Conservación de los Recursos Naturales , Seguimiento de Parámetros Ecológicos , Ecosistema , Pradera , Helmintos/clasificación , Helmintos/aislamiento & purificación , Ganado , Estanques/parasitología , PrevalenciaRESUMEN
Understanding the mechanisms driving host-parasite interactions has important ecological and epidemiological implications. Traditionally, most studies dealing with host-parasite interaction networks have focused on species relationship patterns, and intra-population variation in such networks has been widely overlooked. In this study, we tested whether the composition of parasite communities of five anuran species (Leptodactylus chaquensis, Leptodactylus fuscus, Leptodactylus podicipinus, Pseudis paradoxa and Pithecopus azureus) vary across a pasture pond and a natural reserve site in south-eastern Pantanal, Brazil. We analysed the structure of individual-based networks of these five anuran species, assessed the species roles in the networks and the contribution of host species and body size to interaction strength in the networks, and tested if network ecological attributes varied between the two sites. We observed a total of 17 parasite morphospecies in 151 individual anurans and found that the abundance of parasite species tends to vary, with host species being the main filter driving parasite community structure. The composition of core parasite species remained similar between study sites, and network structure (i.e. parasite richness, interaction diversity, specialization, nestedness and modularity) did not change between pasture and natural reserve. Individual traits of hosts influenced network descriptors since larger hosts presented greater interaction strength independent of the study site. In short, we found that the occurrence of highly connected parasite taxa in both the pasture and the reserve sites may have promoted similarity in network structures, and host body size was the best predictor of associations with parasites in both study sites.
Asunto(s)
Anuros/parasitología , Interacciones Huésped-Parásitos , Parásitos/clasificación , Parásitos/fisiología , Animales , Biota , Brasil , Femenino , Especificidad del Huésped , Parásitos/anatomía & histología , Estanques/parasitologíaRESUMEN
The identification of environmental barriers which govern species distribution is a fundamental concern in ecology. Even though salt was previously identified as a major transition boundary for micro- and macroorganisms alike, the salinities causing species turnover in protistan communities are unknown. We investigated 4.5 million high-quality protistan metabarcodes (V4 region of the SSU rDNA) obtained from 24 shallow salt ponds (salinities 4%-44%) from South America and Europe. Statistical analyses of protistan community profiles identified four salinity classes, which strongly selected for different protistan communities: 4-9%, 14-24%, 27-36% and 38-44%. The proportion of organisms unknown to science is highest in the 14-24% salinity class, showing that environments within this salinity range are an unappreciated reservoir of as yet undiscovered organisms. Distinct higher-rank taxon groups dominated in the four salinity classes in terms of diversity. As increasing salinities require different cellular responses to cope with salt, our results suggest that different evolutionary lineages of protists have evolved distinct haloadaptation strategies. Salinity appears to be a stronger selection factor for the structuring of protistan communities than geography. Yet, we find a higher degree of endemism in shallow salt ponds compared with less isolated ecosystems such as the open ocean. Thus, rules for biogeographic structuring of protistan communities are not universal, but depend on the ecosystem under consideration.
Asunto(s)
Eucariontes/aislamiento & purificación , Estanques/parasitología , Evolución Biológica , Ecosistema , Eucariontes/clasificación , Eucariontes/genética , Europa (Continente) , Filogenia , Estanques/química , Salinidad , América del SurRESUMEN
Given their ubiquitous nature, it is surprising that more oligochaete annelid worms (Annelida: Clitellata) have not adopted an endoparasitic lifestyle. Exceptions, however, are the understudied members of the genus Dero (Allodero) that parasitize the ureters of tree frogs and toads. This study experimentally explores the life cycle and host specificity of Allodero hylae, the worm's use of chemical cues in host searching, and its seasonal prevalence and abundance over a year-long collection period on the Florida Southern College campus. A total of 2,005 A. hylae was collected from the ureter, urinary bladder, or expressed urine of wild Osteopilus septentrionalis ; a significant positive correlation was found between host snout-vent length and parasite intensity for female but not male hosts. Monthly prevalence of A. hylae reached a peak of 58% in April, but never dropped below 20% in any month; mean abundance peaked March-May, whereas few worms were recovered in December and January. Confirming a parasitic lifestyle, wild-collected hosts with intense infections, typically >40 worms, showed obvious dilatation of the ureter wall, and some young-of-the-year O. septentrionalis exposed to A. hylae in the laboratory were killed by the apparent rupture of the host's ureter. The worm has a direct life cycle: worms expelled in the host's urine are capable of locating and re-infecting other hosts within aquatic microhabitats such as bromeliad tanks, and worms can survive for weeks in a free-living environment, even undergoing a morphological change. Further, chemotaxis assays found a positive response to a tree frog attractant for worms recently removed from hosts. Overall, this study provides the first multifaceted investigation on the life history and ecology of any Allodero spp., which offers new insights into an understudied endoparasitic oligochaete.
Asunto(s)
Anuros/parasitología , Estadios del Ciclo de Vida , Oligoquetos/fisiología , Enfermedades Parasitarias en Animales/parasitología , Animales , Quimiotaxis , Femenino , Florida/epidemiología , Especificidad del Huésped , Masculino , Oligoquetos/crecimiento & desarrollo , Enfermedades Parasitarias en Animales/epidemiología , Estanques/parasitología , Prevalencia , Estaciones del Año , Uréter/parasitología , Vejiga Urinaria/parasitología , Orina/parasitologíaRESUMEN
The present work describes the morphology and infraciliature of a new hypotrichous ciliate, Clapsiella magnifica gen. n., sp. n., found in rewetted soil from a temporal pond in Argentina. It was studied by means of live observation and protargol impregnation. Its main diagnostic features are: Flexible hypotrich measuring 250-320 µm × 70-140 µm in vivo; two macronuclear nodules and 4-6 micronuclei. Single contractile vacuole. Cytoplasm transparent, cortical granules absent. Somatic ciliature composed of a tricorona of cirri, three buccal(?) cirri, 6-9 ventral rows, 3-5 right marginal(?) rows, one left marginal row, and 12-17 transverse cirri. Dorsal pattern rather complicated, with about 14 kineties and kinety fragments, with scattered kinetids among them; 17-28 caudal cirri arranged in three rows on dorsal kineties 1, 3, and 7. Remarkably, dorsal kinetids have two or four basal bodies, bearing a stiff bristle arising from left anterior basal body. Adoral zone composed of 70-92 membranelles, occupying about 40% of body length in protargol preparations; paroral and endoral curved, resembling a cyrtohymenid pattern. The peculiar dorsal ciliary arrangement and the unique combination of other characters require the establishment of a new genus for this new species, which is considered incertae sedis in the Hypotricha but possibly related to the oxytrichids.
Asunto(s)
Cilióforos/clasificación , Cilióforos/ultraestructura , Estanques/parasitología , Suelo/parasitología , Argentina , Cilios/ultraestructura , Especificidad de la EspecieRESUMEN
Hypotrichous ciliates collected in the plankton and soil samples from a temporary pond in Buenos Aires province, Argentina, were characterized after live observations and protargol impregnation. Apoamphisiella hymenophora (Stokes) Berger is redescribed and the neotype material deposited. Apoamphisiella hymenophora differs from its congeners in having 2 macronuclear nodules, 1 contractile vacuole with anterior and posterior collecting canals, the absence of cortical granules, 2 cirri behind the rightmost frontal cirrus, 1 postoral cirrus, 6 dorsal rows of dikinetids along with scattered dikinetids on the right body margin, and 3-9 caudal cirri arranged in groups at the ends of dorsal rows 1, 2, and 4. Rigidohymena candens, R. quadrinucleata, Histriculus histrio, Gastrostyla steinii, and Pseudouroleptus caudatus are new for the Argentine microfauna. Since especially the soil ciliates have been almost unexplored in South America, the results from the present investigation describe and contribute to the knowledge of the diversity of these microorganisms within this geographical region.
Asunto(s)
Estanques/parasitología , Sporadotrichina/clasificación , Sporadotrichina/citología , Argentina , Especificidad de la EspecieRESUMEN
Introducción. Pocos estudios describen los factores asociados con la dinámica de transmisión de la malaria, o paludismo, por Plasmodium vivax en las regiones endémicas de Panamá. Objetivo. Caracterizar la dinámica de transmisión de la malaria producida por P. vivax en la región fronteriza de Panamá con Costa Rica. Materiales y métodos. Se llevó a cabo un estudio observacional, descriptivo y transversal. Se evaluaron la incidencia parasitaria anual, el índice de láminas positivas y el índice anual de exámenes de sangre. Se identificaron los anofelinos vectores, y se caracterizaron sus criaderos preferenciales, densidad larvaria e índice de picada/hombre/noche. Se hizo búsqueda pasiva y activa de casos sospechosos mediante examen de gota gruesa. Resultados. De 10.401 muestras de gota gruesa, 83 resultaron positivas para P. vivax. El 84 % de los casos provenía de zonas rurales, el 79 % constituía una población económicamente activa, la mediana de edad fue de 36 años y, la media, de 30 años. El 58,5 % de los casos fueron de sexo masculino. La incidencia parasitaria anual fue de 4,1 por 1.000 habitantes; el índice de láminas positivas fue de 0,8 % y el índice anual de exámenes de sangre fue de 51,9 %. El 65,0 % de los casos diagnosticados registró entre 100 y 2.000 parásitos/μl de sangre. Se identificaron los mosquitos vectores Anopheles albimanus y An. punctimacula. Conclusión. Es necesario el seguimiento de estudios entomológicos, el fortalecimiento de la vigilancia epidemiológica, la consideración de los factores de riesgo y la realización de un trabajo en coordinación con las autoridades de salud de Costa Rica, para controlar la malaria en esta región.
Introduction. Few studies have described the factors associated with Plasmodium vivax transmission dynamics in endemic regions from Panamá. Objective. Malaria transmission dynamics produced by P. vivax were characterized at the border between Panamá and Costa Rica. Materials and methods. In the municipality of Barú, an observational, descriptive and cross-sectional study was undertaken to measure the annual parasite index (API), slide positivity index (SPR), and the annual blood examination rate (ABER). The most frequent symptoms and signs in malaria patients were recorded. The anopheline species were identified in the area and the preferred larval habitats, the density of larval populations in the larval habitats and the bites/human/night were characterized. Results. Of a total of 10,401 thick smear blood samples, 83 were positive for P. vivax. Of these, 84% came from rural areas and 79% were from economically active individuals. The median and average ages were 36 and 30 years, respectively, and 58.5% of the malaria cases were male. API was 4.1/1,000 inhabitants; SPR was 0.8% and ABER was 51.9%. Of the diagnosed cases, 54% showed blood parasitemias ranging between 100-2,000 parasites/μl. The majority of the cases were observed in May and June. Two mosquito vector species were identified-- Anopheles albimanus and An. punctimacula. Conclusion. These observations indicate the advisibility of continued entomological studies, strengthening of epidemiological surveillance, consideration of additional risk factors and evaluation of work performance in the border region. This will require coordination with health authorities of both countries to control malaria in this region.
Asunto(s)
Adolescente , Adulto , Anciano , Animales , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Anopheles/parasitología , Brotes de Enfermedades , Insectos Vectores/parasitología , Malaria Vivax/transmisión , Parasitemia/transmisión , Plasmodium vivax/aislamiento & purificación , Anopheles/crecimiento & desarrollo , Antimaláricos/uso terapéutico , Estudios Transversales , Cloroquina/uso terapéutico , Costa Rica/epidemiología , Reservorios de Enfermedades , Incidencia , Mordeduras y Picaduras de Insectos/epidemiología , Mordeduras y Picaduras de Insectos/parasitología , Larva , Malaria Vivax/sangre , Malaria Vivax/tratamiento farmacológico , Malaria Vivax/epidemiología , Malaria Vivax/parasitología , Carga de Parásitos , Panamá/epidemiología , Parasitemia/sangre , Parasitemia/tratamiento farmacológico , Parasitemia/epidemiología , Parasitemia/parasitología , Estanques/parasitología , Primaquina/uso terapéutico , Población Rural/estadística & datos numéricos , Especificidad de la EspecieRESUMEN
INTRODUCTION: Few studies have described the factors associated with Plasmodium vivax transmission dynamics in endemic regions from Panamá. OBJECTIVE: Malaria transmission dynamics produced by P. vivax were characterized at the border between Panamá and Costa Rica. MATERIALS AND METHODS: In the municipality of Barú, an observational, descriptive and cross-sectional study was undertaken to measure the annual parasite index (API), slide positivity index (SPR), and the annual blood examination rate (ABER). The most frequent symptoms and signs in malaria patients were recorded. The anopheline species were identified in the area and the preferred larval habitats, the density of larval populations in the larval habitats and the bites/human/night were characterized. RESULTS: Of a total of 10,401 thick smear blood samples, 83 were positive for P. vivax. Of these, 84% came from rural areas and 79% were from economically active individuals. The median and average ages were 36 and 30 years, respectively, and 58.5% of the malaria cases were male. API was 4.1/1,000 inhabitants; SPR was 0.8% and ABER was 51.9%. Of the diagnosed cases, 54% showed blood parasitemias ranging between 100-2,000 parasites/µl. The majority of the cases were observed in May and June. Two mosquito vector species were identified-- Anopheles albimanus and An. punctimacula. CONCLUSION: These observations indicate the advisibility of continued entomological studies, strengthening of epidemiological surveillance, consideration of additional risk factors and evaluation of work performance in the border region. This will require coordination with health authorities of both countries to control malaria in this region.