Comparing performance and resistance of two broilers breeds challenged by Eimeria acervulina.

The proposal on the ban of anticoccidials drugs from poultry feed highlights the importance of broiler breeders resistance to Eimeria as a criteria for animal genetic selection. The aim of this study was to compare the resistance between two commercial broiler breeds to Eimeria acervulina. Eight hundred male chicks from two commercial breeds (400 animals each) were housed from 1-42 days of age and randomly divided into 4 treatments with 8 replicates of 25 birds each. Following a factorial design, the treatments were AU, BU (breed A and B, unchallenged), AC and BC (breed A and B, challenged at 14 days of age by gavage with 1 × 106 oocysts of a field strain of E. acervulina). From 1-42 days, feed intake, body weight gain (BWG), feed conversion ratio (FCR), feed efficiency and mean weight (MW) were weekly measured. For the clinical evaluation, feces were sampled from 18 to 24 days for the counting of excreted oocysts and twenty birds per treatment were euthanized at 20 days of age for the scoring of macroscopic lesions in the gut. The breeds did not show statistical differences in performance after the Eimeria challenge in all phases. Breed A presented a higher increase in FCR from 21 to 45 days in comparison to the breed B, which presented a deeper reduction in FI, BWG and MW at all periods post-infection when compared to the breed A. Despite of the challenge, breed A presented better performance indexes (P < 0.05) up to the 28 days of age in comparison to the breed B, however, no significant difference in performance was detected between the breeds at the final age of 42 days. Regardless of the breed, the challenged birds presented significant worsens in all performance parameters from 14 to 42 days of age. The breed B presented a higher (P < 0.05) fecal count of oocysts from 19 to 21 days and higher (P < 0.05) score of macroscopic lesions in the gut at 21 days in comparison to the breed A. The clinical evaluation pointed out a lower resistance of the breed B to the E. acervulina challenge, which could result in significant impacts on the performance in field production conditions.

Volutin granules of Eimeria parasites are acidic compartments and have physiological and structural characteristics similar to acidocalcisomes.

The structural organization of parasites has been the subject of investigation by many groups and has lead to the identification of structures and metabolic pathways that may represent targets for anti-parasitic drugs. A specific group of organelles named acidocalcisomes has been identified in a number of organisms, including the apicomplexan parasites such as Toxoplasma and Plasmodium, where they have been shown to be involved in cation homeostasis, polyphosphate metabolism, and osmoregulation. Their structural counterparts in the apicomplexan parasite Eimeria have not been fully characterized. In this work, the ultrastructural and chemical properties of acidocalcisomes in Eimeria were characterized. Electron microscopy analysis of Eimeria parasites showed the dense organelles called volutin granules similar to acidocalcisomes. Immunolocalization of the vacuolar proton pyrophosphatase, considered as a marker for acidocalcisomes, showed labeling in vesicles of size and distribution similar to the dense organelles seen by electron microscopy. Spectrophotometric measurements of the kinetics of proton uptake showed a vacuolar proton pyrophosphatase activity. X-ray mapping revealed significant amounts of Na, Mg, P, K, Ca, and Zn in their matrix. The results suggest that volutin granules of Eimeria parasites are acidic, dense organelles, and possess structural and chemical properties analogous to those of other acidocalcisomes, suggesting a similar functional role in these parasites.

Acidocalcisomes in Apicomplexan parasites.

Acidocalcisomes are acidic calcium stores found in diverse organisms, being conserved from bacteria to man. They posses an acidic matrix that contains several cations bound to phosphates, mainly present in the form of short and long polyphosphate chains. Their matrix is acidified through the action of proton pumps such as a vacuolar proton ATPase and a vacuolar proton pyrophosphatase. The calcium uptake occurs through a Ca2+/H+ counter transporting ATPase located in the membrane of the organelle. Acidocalcisomes have been identified in a variety of microorganisms, including Apicomplexan parasites such as Plasmodium and Eimeria species, and in Toxoplasma gondii. In this paper, we review the structural, biochemical and physiological aspects of acidocalcisomes in Apicomplexan parasites and discuss their functional roles in the maintenance of intracellular ion homeostasis.

Characterisation and histopathological observations of a selected Brazilian precocious line of Eimeria acervulina.

Precocious lines of Eimeria acervulina "Cu" and "I" strains were obtained after 25 passages of oocysts in chickens that showed a shortening of the prepatent period for first oocyst output from 96 h to 81 and 82 h, respectively. Both precocious lines were evaluated for pathogenicity using as criteria weight gain, lesion score and total oocyst production. Infection of the "Cu" precocious line in chickens showed a high weight gain, low lesion score and low oocyst production, when compared to parent strain infected chickens. However, the results did not show a significant difference in relation to the criteria used above for the E. acervulina "I" precocious line when compared to its parent strain. This suggests a low degree of attenuation for the "I" strain but good attenuation for the precocious "Cu" line. The histopathological observations of chickens infected with the E. acervulina "Cu" parent strain and precocious line, comparing life cycle and intestinal lesions, showed: (1) parasite stages only in the border cells of infected chicken intestinal villi, for the precocious line; (2) parasite stages in the border cells of the intestinal villi and submucosa cells near the Lieberkühn glands of the intestine; and (3) high degree of inflammatory cells around the parasites in chickens infected with the parent strain. The "Cu" strain was also characterized for sensitivity against eight anticoccidial drugs. Sensitivity was observed for four anticoccidial drugs and partial resistance for four other drugs, although the strain had never had previous contact with anticoccidial drugs, suggesting the presence of a natural resistance factor. This Brazilian E. acervulina "Cu" precocious line showed attenuation for pathogenicity in chickens, suggesting that it could be a suitable strain for use as a live vaccine in Brazil.

Avian anticoccidial activity of a novel membrane-interactive peptide selected from phage display libraries.

In the present work, we describe the discovery of PW2, a novel peptide presenting in vitro activity against Eimeria acervulina and E. tenella sporozoites. PW2 was selected from phage display (Ph.D.) peptide libraries by an alternative method of panning using living purified E. acervulina sporozoites as targets. Our results showed that the peptide disrupts the sporozoite pellicle, resembling the effect caused by most natural antimicrobial peptides. PW2 peptide was also effective against fungi and showed low activity against Toxoplasma gondii tachyzoites, but no activity against Trypanosoma cruzi, Crithidia fasciculata epimastigotes, and bacteria. Additionally, the parasiticidal concentrations of PW2 produced a very low lytic effect on mammalian and avian cells. The effectiveness against Eimeria sporozoites and the absence of adverse effects to host cells indicates that PW2 may be used as a model to generate new drugs for the control of avian coccidiosis.

Description of Pythonella scleruri n. sp. (Apicomplexa: Eimeriidae) from a brazilian bird rufous-breasted-leaftosser Sclerurus scansor, 1835 (Passeriformes: Furnariidae)

Coccidian oocysts containing 16 sporocysts with 4 sporozoites in each were observed in a faecal sample from Sclerurus scansor collected in the Itatiaia National Park, southeastern region of Brazil. The oocysts are characterized by ellipsoidal shape measuring 42.5 x 32.8 µm, with smooth, thick doublelayered wall of a greenish-orange colour. An oocyst residuum of numerousscattered granules among the sporocysts in sporulated ones; 16 round sporocysts, averaging 10.5 x 10 µm each containing four elongated sporozoites; presence of residuum; absence of Stieda body. The presently described coccidian, recorded for the first time in birds, is a new species named P. scleruri.

Experimental infection of swine by Isospora sius Biester 1934 for species confirmation

A survey of Isopora suis performed in 177 faecal samples from 30 swine farms detected thin wall type I. suis oocysts in seven samples. This type of oocysts measuring 23.9 by 20.7 µm had a retracted thin wall similar to that of the genus Sarcocystis. This type of oocysts, isolated from four different faecal samples, was inoculated in four-five-days-old piglets free of contamination in order to verify the life cycle and pathogenicity of the species. The pigs were kept in individual metal cages and fed with cow milk. Daily faecal collections and examinations were performed until the 21st day after infection. MacMaster and Sheather's methods were used for oocyst counting and identification. Infected piglets produced yellowish-pastry diarrhoea with slight dehydration. The prepatent and patent periods were respectively from 6 to 9 and 3 to 10 days infection. Oocyst elimination was interrupted on the 10th and 11th days after infection with biphasic cycles. Thin and thick wall oocysts were detected in the same faecal samples. Thin walls were not observed in unsporulated oocysts. The observations suggest that this type of oocysts could appear in specific strains which occur in the later stages of their development. These oocysts seem to be responsible for clinical and pathogenic signs of neonatal isosporosis in pigs.

Levantamento de coccidiose aviária em três granjas de frangos de corte na regiäo de Campinas - Säo Paulo - Brasil / Survey of avian coccidiosis from three poultry farms in the region of Campinas, state of Säo Paulo, Brazil

Verificou-se a presença de coccidiose aviária, em três granjas da Regiäo de Campinas, Säo Paulo, Brasil. A identificaçäo das espécies de Eimeria foi feita através de método de colheita de amostras de fezes frescas e passagem em 210 aves sadias de duas a três semanas de idade, obedecendo às seguintes características espécie - específicas: localizaçäo do parasita no trato digestivo, tipo de lesöes, tamanho dos oocistos, período pré-patente dos oocistos e formas evolutivas mais características dos parasitas. Foram identificadas, nas três granjas, seis espécies de Eimeria: E. acervulina, E. maxima, E. mitis, E. necatrix, E. praecox e E. tenella. O número de oocistos nos boxes foi bem maior nas granja 1 e 2, fato que foi também comprovado pela passagem dos oocistos em frangos sadios: mostrou maior severidade de infecçäo e a consequente presença de lesöes na mucosa intestinal, com inóculo das duas primeiras granjas, especialmente granja 2, näo causando lesöes aparentes na maioria das aves, com inóculo da granja 3. As espécies de Eimeria e o número de oocistos variavam conforme a época da coleta, tendo prevalecido nas granjas a coccidiose subclínica. Discute-se a possível interferência do uso inadequado dos antibióticos ionóforos, da resistência das eimerias aos mesmos e da diferença de densidade de criaçäo das aves, em relaçäo a coccidiose, nas três granjas

The epidemiology and control of schistosomiasis mansoni where Biomphalaria tenagophila is the snail host

Desde 1980, está-se estudando a epidemiologia e o controle da esquistossomose mansônica no Município de Pedro de Toledo (Estado de Säo Paulo, Brasil). Em 1980 a prevalência avaliada por exame de fezes (métodos de Kato-Katz) foi de 22,8%. Estatisticamente, ao nível de 5%, näo houve diferença nas prevalências observadas nas zonas rural e urbana. A intensidade de infecçäo foi baixa (média geométrica de 58,5 ovos por grama de fezes). As maiores prevalências e intensidades de infecçäo foram registradas na faixa etária de 5 a 29 anos. Geralmente a transmissäo da endemia verificou-se durante o lazer. Apenas 0,4% de B. tenagophila mostraram-se positivos para cercárias de S. mansoni. A maioria dos portadores era assintomático. O programa de controle foi intensificado após avaliaçäo dos dados de 1980, resultando em diminuiçäo acentuada da prevalência de 22,8% em 1980 para 6%. Esta prevalência residual vem se mantendo ate 1987. Agora iniciamos estudos para investigar as possíveis causas dessa prevalência residual.

Competição biológica entre Biomphalaria glabrata (Say, 1818) e Biomphalaria tenagophila (D’Orbgny 1835), em criadouros naturais no Município de Ourinhos, Estado de São Paulo-Brasil / Biological competition between Biomphalaria glabrata (Say, 1818) and Biomphalaria tenagophila (D’Orbgny,1835), observed in their natural breending sites in Ourinhos, State of São Paulo-Brazil

Foram feitas observações sobre a provável competição entre Biomphalaria glabrata e Biomphalaria tenagophila, em três criadouros do tipo vala, situados no Município de Ourinhos, (SP), durante o período de 27/11/1973 a 20/02/1979. As coletas foram realizadas trimestralmente até dezembro de 1976 e semestralmente de 1977 a 1979, num total de 17 capturas. Foram coletados 5.249 exemplares de Biomphalaria tenagophila e 353 de Biomphalaria glabrata no criadouro 1; no criadouro 2 o total de exemplares foi de 1703 e 64 para Biomphalaria tenagophila e Biomphalaria glabrata, respectivamente e no criadouro 3, 1249 e 4 exemplares de Biomphalaria tenagophila e Biomphalaria glabrata respectivamente. Apenas os dados relativos ao primeiro criadouro forneceram informações relacionadas com o deslocamento de Biomphalaria glabrata e Biomphalaria tenagophila, sendo que a análise estatística sugeriu ter havido competição entre as duas espécies estudadas com tendência à exclusão de Biomphalaria glabrata. A substituição parece ter ocorrido num período de pelo menos cinco anos. Apesar de terem sido observadas evidências de deslocamento competitivo entre as duas espécies, não foi possível detectar o mecanismo do fenômeno.