Phoretic mites (Rhinoseius spp. ) in Apodiformes from Cerrado and Pantanal Biomes in midwestern Brazil / Ácaros Foréticos (Rhinoseius spp. ) em Apodiformes dos Biomas Cerrado e Pantanal no Centro-Oeste do Brasil

Abstract Nasal mites are commonly found in hummingbirds (Apodiformes). In most cases, endoparasitic mites were reported to parasitize the respiratory system, particularly the anterior nasal chambers, larynx, trachea, lungs, and the air and conjunctival sacs. However, some mites are only carried by hummingbirds, because flowers serving as a nutrient source for these small mites, such as for Apodiformes, a tropical nectar-feeding in their natural habitat. From August 2012 to May 2014, humminbirds were captured using mist nets, and examined for the presence of nasal mites (identified according to specific keys) in the Pantanal, and Cerrado biomes, from the Mato Grosso state, midwestern Brazil. Overall, 76 Apodiform specimens, from the Trochilidae family were captured, and 20 female nasal mites, identified as being from the Rhinoseius genus, were collected from eight hosts (10.5%), of the following species: Amazilia fimbriata, Amazilia versicolor, Eupetonema macroura, and Thalurania furcata. The Rhinoseius spp. has been reported on, in many ecosystems in the Americas, including Brazil, however, this is the first report on Apodiformes from the Pantanal biome. Phoretic mites are not responsible for direct damage to the population of Apodiformes, as they are not pathogenic. However, they compete for food with hummingbirds and decrease the quantity of food available in the environment. They also affect the reproductive dynamics of plants, feed on pollen, and interfere with the intricacies of the biodiversity where they live.

Resumo Os ácaros nasais são comumente encontrados em beija-flores (Apodiformes). Na maioria dos casos, os ácaros foram relatados como endoparasitas, parasitando o sistema respiratório, particularmente as câmaras nasais anteriores, a laringe, a traqueia, os pulmões e os sacos aéreos e conjuntivais. No entanto, alguns ácaros são transportados apenas por beija-flores, pois flores servem como fonte de nutrientes para esses pequenos ácaros, assim como para Apodiformes tropicais alimentados de néctar em seu habitat natural. De agosto de 2012 a maio de 2014, beija-flores foram capturadas com redes de neblina e examinadas quanto à presença de ácaros nasais (identificados de acordo com chaves específicas) nos biomas Pantanal e Cerrado, no estado do Mato Grosso, Centro-Oeste do Brasil. No total, 76 exemplares Apodiformes da família Trochilidae foram capturados e 20 fêmeas de ácaros nasais, identificados como pertencentes ao gênero Rhinoseius, foram coletados de oito hospedeiros (10,5%), das seguintes espécies: Amazilia fimbriata, Amazilia versicolor, Eupetonema macroura e Thalurania furcata. Rhinoseius spp. foi relatado em muitos ecossistemas nas Américas, incluindo o Brasil, no entanto, este é o primeiro relato em Apodiformes do bioma Pantanal. Os ácaros foréticos não são responsáveis ​​por danos diretos à população de Apodiformes, pois não são patogênicos. No entanto, eles competem por comida com beija-flores e diminuem a quantidade de comida disponível no ambiente. Eles também afetam a dinâmica reprodutiva das plantas, se alimentam de pólen e interferem nas interações da biodiversidade em que vivem.

Phoretic mites (Rhinoseius spp.) in Apodiformes from Cerrado and Pantanal Biomes in midwestern Brazil.

Nasal mites are commonly found in hummingbirds (Apodiformes). In most cases, endoparasitic mites were reported to parasitize the respiratory system, particularly the anterior nasal chambers, larynx, trachea, lungs, and the air and conjunctival sacs. However, some mites are only carried by hummingbirds, because flowers serving as a nutrient source for these small mites, such as for Apodiformes, a tropical nectar-feeding in their natural habitat. From August 2012 to May 2014, humminbirds were captured using mist nets, and examined for the presence of nasal mites (identified according to specific keys) in the Pantanal, and Cerrado biomes, from the Mato Grosso state, midwestern Brazil. Overall, 76 Apodiform specimens, from the Trochilidae family were captured, and 20 female nasal mites, identified as being from the Rhinoseius genus, were collected from eight hosts (10.5%), of the following species: Amazilia fimbriata, Amazilia versicolor, Eupetonema macroura, and Thalurania furcata. The Rhinoseius spp. has been reported on, in many ecosystems in the Americas, including Brazil, however, this is the first report on Apodiformes from the Pantanal biome. Phoretic mites are not responsible for direct damage to the population of Apodiformes, as they are not pathogenic. However, they compete for food with hummingbirds and decrease the quantity of food available in the environment. They also affect the reproductive dynamics of plants, feed on pollen, and interfere with the intricacies of the biodiversity where they live.

Centrocestus formosanus (Trematoda: Heterophyidae) in Melanoides tuberculata (Gastropoda: Thiaridae) from Vila do Abraão, Ilha Grande, Rio de Janeiro, Brazil / Centrocestus formosanus (Trematoda: Heterophyidae) em Melanoides tuberculata (Gastropoda, Thiaridae) da Vila do Abraão, Ilha Grande, Rio de Janeiro, Brasil

Abstract Pleurolophocercous cercariae found in the invasive gastropod Melanoides tuberculata (Müller, 1774) collected in a stream of the Vila do Abraão, Ilha Grande, Angra dos Reis, Rio de Janeiro, Brazil were used for experimental infection that enabled the identification of the heterophyid trematode Centrocestus formosanus (Nishigori, 1924). The parasite has been found in the locality since 2007, after two years of the introduction of M. tuberculata. Recently, from a sample of 483 specimens collected in June 2013, 101 (21%) were found infected with parasite. The potential environmental impacts caused by the parasite occurrence could be underestimated in the country, and actions to monitor and control both the parasite and the mollusk are necessary.

Resumo Cercárias do tipo pleurolofocerca encontradas no gastrópode invasor Melanoides tuberculata (Müller, 1774) coletados em um riacho da Vila do Abraão em Ilha Grande, Angra dos Reis, Rio de Janeiro, Brasil foram utilizadas em estudos de infecção experimental que possibilitaram a identificação do trematódeo heterofiídeo Centrocestus formosanus (Nishigori, 1924). O parasito vem sendo encontrado na localidade desde 2007, dois anos após a introdução do molusco. Recentemente, de uma amostra de 483 espécimes coletados em junho de 2013, 101 (21%) apresentavam-se infectados pelo parasito. Os potenciais impactos ambientais ocasionados pela ocorrência deste parasito podem estar sendo subestimados no país, sendo necessárias ações visando o monitoramento e controle tanto do parasito quanto do molusco.

Centrocestus formosanus (Trematoda: Heterophyidae) in Melanoides tuberculata (Gastropoda: Thiaridae) from Vila do Abraão, Ilha Grande, Rio de Janeiro, Brazil.

Pleurolophocercous cercariae found in the invasive gastropod Melanoides tuberculata (Müller, 1774) collected in a stream of the Vila do Abraão, Ilha Grande, Angra dos Reis, Rio de Janeiro, Brazil were used for experimental infection that enabled the identification of the heterophyid trematode Centrocestus formosanus (Nishigori, 1924). The parasite has been found in the locality since 2007, after two years of the introduction of M. tuberculata. Recently, from a sample of 483 specimens collected in June 2013, 101 (21%) were found infected with parasite. The potential environmental impacts caused by the parasite occurrence could be underestimated in the country, and actions to monitor and control both the parasite and the mollusk are necessary.

Phoretic mites (Rhinoseius spp.) in Apodiformes from Cerrado and Pantanal Biomes in midwestern Brazil

Abstract Nasal mites are commonly found in hummingbirds (Apodiformes). In most cases, endoparasitic mites were reported to parasitize the respiratory system, particularly the anterior nasal chambers, larynx, trachea, lungs, and the air and conjunctival sacs. However, some mites are only carried by hummingbirds, because flowers serving as a nutrient source for these small mites, such as for Apodiformes, a tropical nectar-feeding in their natural habitat. From August 2012 to May 2014, humminbirds were captured using mist nets, and examined for the presence of nasal mites (identified according to specific keys) in the Pantanal, and Cerrado biomes, from the Mato Grosso state, midwestern Brazil. Overall, 76 Apodiform specimens, from the Trochilidae family were captured, and 20 female nasal mites, identified as being from the Rhinoseius genus, were collected from eight hosts (10.5%), of the following species: Amazilia fimbriata, Amazilia versicolor, Eupetonema macroura, and Thalurania furcata. The Rhinoseius spp. has been reported on, in many ecosystems in the Americas, including Brazil, however, this is the first report on Apodiformes from the Pantanal biome. Phoretic mites are not responsible for direct damage to the population of Apodiformes, as they are not pathogenic. However, they compete for food with hummingbirds and decrease the quantity of food available in the environment. They also affect the reproductive dynamics of plants, feed on pollen, and interfere with the intricacies of the biodiversity where they live.

Resumo Os ácaros nasais são comumente encontrados em beija-flores (Apodiformes). Na maioria dos casos, os ácaros foram relatados como endoparasitas, parasitando o sistema respiratório, particularmente as câmaras nasais anteriores, a laringe, a traqueia, os pulmões e os sacos aéreos e conjuntivais. No entanto, alguns ácaros são transportados apenas por beija-flores, pois flores servem como fonte de nutrientes para esses pequenos ácaros, assim como para Apodiformes tropicais alimentados de néctar em seu habitat natural. De agosto de 2012 a maio de 2014, beija-flores foram capturadas com redes de neblina e examinadas quanto à presença de ácaros nasais (identificados de acordo com chaves específicas) nos biomas Pantanal e Cerrado, no estado do Mato Grosso, Centro-Oeste do Brasil. No total, 76 exemplares Apodiformes da família Trochilidae foram capturados e 20 fêmeas de ácaros nasais, identificados como pertencentes ao gênero Rhinoseius, foram coletados de oito hospedeiros (10,5%), das seguintes espécies: Amazilia fimbriata, Amazilia versicolor, Eupetonema macroura e Thalurania furcata. Rhinoseius spp. foi relatado em muitos ecossistemas nas Américas, incluindo o Brasil, no entanto, este é o primeiro relato em Apodiformes do bioma Pantanal. Os ácaros foréticos não são responsáveis por danos diretos à população de Apodiformes, pois não são patogênicos. No entanto, eles competem por comida com beija-flores e diminuem a quantidade de comida disponível no ambiente. Eles também afetam a dinâmica reprodutiva das plantas, se alimentam de pólen e interferem nas interações da biodiversidade em que vivem.

A survey of tick-borne pathogens in dogs and their ticks in the Pantanal biome, Brazil.

Tick and blood samples collected from domestic dogs in the Brazilian Pantanal were tested by molecular methods for the presence of tick-borne protozoa and bacteria. Among 320 sampled dogs, 3.13% were infected by Babesia vogeli (Piroplasmida: Babesiidae), 8.75% by Hepatozoon canis (Eucoccidiorida: Hepatozoidae), 7.19% by Anaplasma platys (Rickettsiales: Anaplasmataceae), and 0.94% by an unclassified Anaplasma sp. In three tick species collected from dogs, the following tick-borne agents were detected: (a) B. vogeli, An. platys and Ehrlichia canis (Rickettsiales: Anaplasmataceae), infecting Rhipicephalus sanguineus sensu lato (Ixodida: Ixodidae) ticks; (b) H. canis, an unclassified Anaplasma sp. and Rickettsia amblyommii (Rickettsiales: Rickettsiaceae), infecting Amblyomma cajennense sensu lato (Ixodida: Ixodidae) ticks, and (c) Rickettsia sp. strain Atlantic rainforest, an emerging human pathogen, infecting Amblyomma ovale ticks. Molecular analysis, based on a mitochondrial gene, revealed that the Am. cajennense s.l. ticks of the present study corresponded to Amblyomma sculptum, a member of the Am. cajennense species complex, and that Rh. sanguineus s.l. belonged to the tropical lineage. Whereas dogs are exposed to a number of tick-borne bacterial and protozoan agents in the Pantanal biome, humans are potentially exposed to infection by spotted fever group rickettsiae (e.g. R. amblyommii and Rickettsia sp. strain Atlantic rainforest) because both Am. sculptum and Am. ovale are among the most important human-biting ticks in Brazil.

Can the same species of Platynosomum (Trematoda: Dicrocoeliidae) infect both mammalian and avian hosts?

The importance of platynosomiasis has increased in feline veterinary practice, but aspects related to the specificity of Platynosomum spp. in definitive hosts requires further study. Although morphological traits suggest that the same species, P. illiciens, may infect both birds and mammals, the synonymies previously proposed have not been widely accepted, likely because host specificity is assumed. In addition, the name P. fastosum has frequently been used for parasites recovered from mammals. In the present study, metacercariae (n= 100/animal) of P. illiciens recovered from lizards (Hemidactylus mabouia) in Brazil were fed to Australian parakeets (Melopsittacus undulatus) and mice. Two parasites were recovered from the liver of one M. undulatus specimen during a necropsy that was performed 105 days after infection, and all mice were found to be infected with 37 ± 12 (18-48) parasites. The morphology of the P. illiciens obtained from the parakeet was similar to that of parasites obtained from mice and those described previously from naturally infected birds and mammals. Non-specificity of P. illiciens in hosts is discussed briefly, based on the parasitological and morphological results obtained during the avian experimental platynosomiasis and the epidemiology and geographical distribution of this parasite.

Detecção de Theileria equi e Babesia caballi e anticorpos anti-Ehrlichia spp. em equídeos do Pantanal Mato-Grossense, Brasil / Detection of Theileria equi, Babesia caballi and anti-Ehrlichia spp antibodies in equides from the Pantanal of Mato Grosso State

O presente estudo avaliou equídeos de 19 fazendas da região do Pantanal Mato-Grossense, sendo 121 equídeos testados pela reação em cadeia pela polimerase (PCR), para detectar fragmentos dos genes dos seguintes gêneros: Babesia, Theileria, Anaplasma, Ehrlichia, e Neorickettsia, e pela reação de imunofluorescência indireta (RIFI), para detectar anticorpos anti-Ehrlichia spp. Das amostras testadas na PCR, 17 (14,0%) animais de nove (47,3%) fazendas foram positivos. Das amostras positivas, 16 foram 100% idênticas a sequencias de Theileria equi e uma foi 99% similar à sequência de Babesia caballi, todas disponíveis no GenBank. Pela RIFI, 48 (39,6%) equídeos foram soropositivos para antígenos de E. canis, sendo 40 (83,3%) amostras com títulos de 40 e oito (16,6%) com títulos de 320. Todas as fazendas avaliadas (100%) apresentaram equídeos soropositivos. Os resultados do presente estudo demonstram que T. equi e B. caballi infectam equinos na região, e a presença de anticorpos anti-Ehrlichia spp. indica a circulação de espécies antigenicamente relacionadas aos gêneros Ehrlichia e Anaplasma, apesar de a negatividade nos exames de PCR indicar provável processo crônico desses agentes.

The present study evaluated 121 equids from 19 ranches in the Pantanal region of Mato Grosso State through Polimerase Chain Raction (PCR) to detect Babesia, Theileria, Anaplasma, Ehrlichia and Neorickettsia partial genes and the Imunofluorescent Antibody Test (IFAT) to evaluate anti-Ehrlichia spp. antibodies. From the total tested in PCR, 17 (14.0%) equids from 9 (47.3%) farms were positive, and 16 yielded amplicons 100% identical to Theileria equi and one presented 99% similarity to Babesia caballi available on GenBank. Forty eight (39.6%) equids were positive by IFAT and 40 showed titers of 40 (83.3%) and 8 showed titers of 320 (16.6%). All ranches (100%) presented seropositive equids. Our results showed that T. equi and B. caballi are infecting equids in the region and the presence of anti-Ehrlichia antibodies suggests that species closely related to the genera Ehrlichia and Anaplasma are circulating among the equid local population. Moreover, the negative results in PCR is possibly related to the chronic infection phase.

Experimental and molecular study of cercariae of Clinostomum sp. (Trematoda: Clinostomidae) from Biomphalaria spp. (Mollusca: Planorbidae) in Brazil.

Despite the large number of reports of species of Clinostomum from vertebrate hosts in South America, studies evaluating the molluscan transmitters of these parasites are scarce. In the present study, clinostomatoid cercariae shed from 0.02% (4/17,485) specimens of Biomphalaria spp., collected at the Pampulha reservoir, Belo Horizonte, Minas Gerais, Brazil, were used for experimental infection of Poecilia reticulata . Samples of cercariae from molluscs and metacercariae experimentally obtained from fish were subjected to morphological and molecular analyses and compared with species of Clinostomum reported in the Americas. The cercariae and metacercariae, here identified as Clinostomum sp., present general morphology similar to that reported for Clinostomum marginatum , however, from molecular point of view, differ significantly from North American C. marginatum and other species of Clinostomum reported in South America. These results suggest that the diversity of Clinostomum found in Brazil may be underestimated. Additional studies aimed at molecular characterization of South American species of Clinostomum, including the finding of specimens with sequences similar to that reported for C. marginatum in North America are required.

Phenotypic plasticity of male Schistosoma mansoni from the peritoneal cavity and hepatic portal system of laboratory mice and hamsters.

Morphometric analysis of Schistosoma mansoni male worms obtained from AKR/J and Swiss mice was carried out. Rodents infected by the intraperitoneal route with 80 cercariae of the schistosome (LE strain) were killed by cervical dislocation at 45 and 60 days post-infection and both peritoneal lavage and perfusion of the portal system were performed for the recovery of adult worms. Characteristics including total body length, the distance between oral and ventral suckers, extension of testicular mass and the number of testes were considered in the morphological analysis. Changes that occurred in S. mansoni recovered from the peritoneal cavity or from the portal system of AKR/J and Swiss mice included total body length and reproductive characteristics. Significant morphometric alterations were also observed when worms recovered from the portal system of both strains of mice were compared with the schistosomes obtained from hamsters (Mesocricetus auratus), the vertebrate host in which the LE strain had been adapted and maintained by successive passages for more than four decades. The present results reinforce the idea that S. mansoni has high plastic potential and adaptive capacity.

Genetic diversity of Ehrlichia canis in Brazil.

Canine monocytic ehrlichiosis is a highly prevalent disease in Brazil, where the genetic diversity of Ehrlichia canis remains undefined. In this study, we used the TRP36 gene to examine the genetic diversity of E. canis strains from naturally infected dogs residing in five distinct geographic regions in Brazil. E. canis DNA was detected in 82/126 (65%) dogs by dsb-specific PCR and E. canis was isolated in cell culture from 13 dogs. Sequences obtained from dsb genes amplified from the isolates were identical to the US E. canis strain. An extended molecular characterization based on the TRP36 gene identified two major genogroups based on differences among eight isolates. Isolates with tandem repeat amino acid sequence (TEDSVSAPA) identical to the previously reported TRP36 sequence were found in the midwest, northeast and southeast regions of Brazil, and classified into the US genogroup. A novel Brazilian genotype with a different tandem repeat sequence (ASVVPEAE) was also identified in midwest, northern and southern regions. Similarity in the N-terminal sequence of a US genogroup member with the Brazilian genogroup suggested that genomic recombination between the two genogroups may have occurred. Other subtypes within the Brazilian genogroup were also identified using C-terminal amino acid divergence. We identified two distinct major Brazilian genogroups and several subtypes based on analysis of TRP36, and such information will be useful for further genotyping and possible associations with disease severity, understanding of the genetic and antigenic variability of E. canis, and for developing strain-specific vaccines and diagnostic methods based on TRP36.

Biomphalaria straminea (Mollusca: Planorbidae) as an intermediate host of Ribeiroia sp. (Trematoda: Psilostomidae) in Brazil.

Species of Ribeiroia are trematode parasites of birds and mammals that have acquired notoriety since Ribeiroia ondatrae was identified as a cause of mortality and malformations in North American amphibians. Although species of Ribeiroia have been reported in vertebrate hosts in South America, the snails involved in its transmission remain unknown in Brazil. During malacological studies conducted at Pampulha Reservoir, Belo Horizonte, Minas Gerais, Brazil, between January 2009 and February 2012, in total 14,264 specimens of Biomphalaria straminea were collected, of which 192 (1.35%) were infected with gymnocephalous cercariae. The larvae were used for experimental infection of laboratory-reared guppies ( Poecilia reticulata ); metacercariae obtained in these fishes were orally administered to domestic ducks (Cairina moschata); and adult parasites were obtained from the proventriculus 10 days after infection. Based on morphological and molecular analyses, the parasite was identified as Ribeiroia sp., a species morphologically similar to R. ondatrae , but distinctly different at the molecular level. This is the first report of larvae of Ribeiroia in Brazil and B. straminea as a new intermediate host for this genus.

Biomphalaria straminea and Biomphalaria glabrata (Mollusca: Planorbidae) as new intermediate hosts of the fish eyefluke Austrodiplostomum compactum (Trematoda: Diplostomidae) in Brazil.

Austrodiplostomum compactum has been involved in cases of ocular diplostomiasis in several species of fish in Brazil, but the molluscan intermediate hosts of the parasite remain unknown. In the present study, malacological surveys were carried out at Pampulha Reservoir, Belo Horizonte, Minas Gerais, Brazil, between January 2009 and July 2012. A total of 16,119 specimens of Biomphalaria spp. were collected and examined, of which 68/14,948 specimens (0.45%) of Biomphalaria straminea and 6/541 (1.11%) of Biomphalaria glabrata were found harboring a strigeid cercariae. Groups of 5 specimens of Cyprinius carpio were experimentally infected with these cercariae (100 larvae/fish), and metacercariae were recovered from the eyes of the fish, 65 days after infection, with a mean intensity of infection of 10.4 (8-13) metacercariae/fish. Morphological study on cercariae and metacercariae identified them as A. compactum . This is the first record of cercariae of A. compactum in Brazil, and B. straminea and B. glabrata as new intermediate hosts for the parasite.

Current applications of oogram methodology in experimental schistosomiasis; fecundity of female Schistosoma mansoni and egg release in the intestine of AKR/J mice following immunomodulatory treatment with pentoxifylline.

Oogram methodology permitted a direct assessment of the fecundity of Schistosoma mansoni and the passage of parasite eggs from mesenteric vessels into the intestinal lumen in AKR/J mice that had been infected via the intraperitoneal route with 60 cercariae of the trematode and later subjected to short-term subcutaneous treatments with pentoxifylline (PTX). The administration of PTX did not change oviposition kinetics, the individual fecundity of female parasites (as determined by the study of the ratio of second-stage S. mansoni eggs per g intestine/number of female parasites recovered from the portal system), nor the number of mature and dead eggs retained in the host tissue, though the drug has known immunomodulatory effects, as shown previously in experimental schistosomiasis. A better appraisal was also carried out, including the study of statistical parameters, concerning the utilization of the ratios of each stage of immature eggs (first to fourth) per g intestine/number of female worms from the portal system. The second-stage eggs had the lowest variability, confirming that the utilization of this stage as an indicator of the individual fecundity of parasite females is indeed viable. In the light of our findings, current uses of oogram methodology are discussed. Moreover, additional consideration is given to data obtained in the present study concerning intraperitoneal infection with S. mansoni cercariae in both untreated and treated mice of the AKR/J strain, such as the recovery of mature worms, eggs and free granulomas from the peritoneal cavity of these rodents.

Ehrlichia canis in dogs in a semiarid region of Northeastern Brazil: serology, molecular detection and associated factors.

This study investigated infection by Ehrlichia spp. agents by PCR, immunofluorescence assay test (IFAT), and by Giemsa-stained blood smears in 108 dogs from a semiarid region of the state of Paraíba, Northeastern Brazil. Seventy-five (69.4%) of the 108 dogs were found to be seropositive to Ehrlichia canis, while only four dogs (3.7%) were positive in real-time PCR for E. canis. In six dogs (5.6%) E. canis-like morulae were observed in monocytes. Animals that stayed in environment whose floor was dried dirt, and dogs whose owners reported low frequency of cleaning the dog environment had higher (P<0.05) PCR positivity for E. canis. Increasing seropositivity was found in older dogs (P=0.012). This study provides the first molecular detection of E. canis in the semiarid region of Northeastern Brazil.

Random regression models using Legendre orthogonal polynomials to evaluate the milk production of Alpine goats.

The objective of this study was to identify the best random regression model using Legendre orthogonal polynomials to evaluate Alpine goats genetically and to estimate the parameters for test day milk yield. On the test day, we analyzed 20,710 records of milk yield of 667 goats from the Goat Sector of the Universidade Federal de Viçosa. The evaluated models had combinations of distinct fitting orders for polynomials (2-5), random genetic (1-7), and permanent environmental (1-7) fixed curves and a number of classes for residual variance (2, 4, 5, and 6). WOMBAT software was used for all genetic analyses. A random regression model using the best Legendre orthogonal polynomial for genetic evaluation of milk yield on the test day of Alpine goats considered a fixed curve of order 4, curve of genetic additive effects of order 2, curve of permanent environmental effects of order 7, and a minimum of 5 classes of residual variance because it was the most economical model among those that were equivalent to the complete model by the likelihood ratio test. Phenotypic variance and heritability were higher at the end of the lactation period, indicating that the length of lactation has more genetic components in relation to the production peak and persistence. It is very important that the evaluation utilizes the best combination of fixed, genetic additive and permanent environmental regressions, and number of classes of heterogeneous residual variance for genetic evaluation using random regression models, thereby enhancing the precision and accuracy of the estimates of parameters and prediction of genetic values.

Apoptotic mechanisms are involved in the death of Strongyloides venezuelensis after triggering of nitric oxide.

Despite progress in understanding the role of nitric oxide (NO) in the pathogenesis of helminth infections, the role in strongyloidosis is unknown. Firstly, we studied the production of NO in mice infected with Strongyloides venezuelensis as well as in macrophage cultures stimulated with parasite antigens. Somatic larvae 3 (L3) and excretory-secretory female antigens stimulate specific NO production measured by Griess reaction and expression of inducible NO synthase by RT-PCR and quantitative PCR. Moreover, mice infected with S. venezuelensis produce NO in migration stages. Secondly, we analysed the effect of NO production on L3 and females of S. venezuelensis using NO donors such as diethylenetriamine and 3,3-bis(aminoethyl)-1-hydroxy-2-oxo-1-triazene. Parasites died after NO donor treatment in a dose-dependent manner. Finally, apoptotic mechanisms are involved in the death of S. venezuelensis larvae.

Melanoides tuberculata (Mollusca: Thiaridae) harboring renicolid cercariae (Trematoda: Renicolidae) in Brazil.

Melanoides tuberculata , naturally infected by gymnocephalous cercariae, were found in aquatic collections from Belo Horizonte, Minas Gerais, Brazil. After morphological characterization, larvae were used for experimental infection of Poecilia reticulata. Metacercariae were obtained from the liver of these fish, which were also found to be naturally infected in the same locality. The morphology and biology of the developmental stages of trematodes we obtained were characteristic of Renicola sp. This is the first record of renicolid cercariae and metacercariae in Brazil.