Two new Eimeria species (Apicomplexa: Eimeriidae) from the yellow-crowned Amazon Amazona ochrocephala (Aves: Psittacidae) in Brazil.

In this study, we describe 2 new species of Eimeria associated with the yellow-crowned Amazon Amazona ochrocephala. Eimeria amazonae n. sp. has bilayered, ellipsoidal, and smooth oocysts that measure 48.9 × 36.2 µm; the length/width ratio is 1.35. The micropyle and oocyst residuum are both absent, but the polar granule is present. Ovoidal sporocysts are 22.2 × 11.9 µm. Stieda and sub-Stieda bodies and sporocyst residuum are present. The 2 elongate sporozoites are curved and measure 18.1 × 3.4 µm; both have 2 refractile bodies. Eimeria ochrocephalae n. sp. has bilayered, ellipsoidal, and smooth oocysts that measure 43.8 × 27.7 µm; the length/width ratio is 1.58. The micropyle and oocyst residuum are absent, but the polar granule is present; ovoidal sporocysts are 20.6 × 10.1 µm. Stieda and sub-Stieda bodies and sporocyst residuum are present; 2 elongate and curved sporozoites are 15.8 × 3.4 µm, each of which has 2 refractile bodies.

A comparison between IgG antibodies against Eimeria acervulina, E. maxima, and E. tenella and oocyst shedding in broiler-breeders vaccinated with live anticoccidial vaccines.

The aim of this study was to compare the IgG response against Eimeria acervulina, E. maxima, and E. tenella and oocyst shedding in broiler-breeders vaccinated with live (virulent or attenuated) anticoccidial vaccines. Serum and faeces samples were collected from chickens before (4 days of age) and after (25 days of age) vaccination with virulent (group A) or attenuated (group B) vaccines and unvaccinated control birds (group C). Criteria for evaluation included the number of oocysts shed on the litter (McMaster technique), the levels of specific serum IgG (ELISA) and the frequencies of antigenic fractions recognised by IgG antibodies (immunoblotting). The results demonstrated that the virulent vaccine (A) presented an ideal association (low oocyst number and high IgG positive rate) for E. acervulina and E. tenella while the immunised flock with the attenuated vaccine (B) demonstrated this ideal association only for E. maxima. Both vaccinated flocks demonstrated a better association for three Eimeria spp. studied when compared to the control group, which presented a divergent association (high oocyst number and low IgG positive rate), particularly for E. acervulina. Immunoblotting assays revealed different antigenic fractions that may be considered as immunodominant antigens. The present study suggests that E. acervulina is critically present in the region studied and the use of live anticoccidial vaccines (virulent or attenuated) showed to be effective to control the clinical coccidiosis in vaccinated flocks.

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 mm, with smooth, thick double-layered wall of a greenish-orange colour. An oocyst residuum of numerous scattered granules among the sporocysts in sporulated ones; 16 round sporocysts, averaging 10.5 x 10 mm 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 suis Biester 1934 for species confirmation.

A survey of Isospora suis performed in 177 faecal samples from 30 swine farms detected thin wall type I. suis oocysts in seven samples. This type of oocyst measuring 23.9 by 20.7 microns 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-pasty diarrhoea with slight dehydration. The prepatent and patent periods were respectively from 6 to 9 and 3 to 10 days after 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 oocytes. 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.

Prevalence of porcine neonatal isosporosis in Brazil.

The prevalence of Isospora suis and clinical signs of isosporosis were observed in 33 swine farms from 20 sites in the southeastern state of São Paulo, Brazil. The study was performed by collecting 177 faecal samples from nursing and weaned piglets. A history of clinical neonatal isosporosis, as well as the type of farrowing and nursery houses and the pig management in the farms were correlated to the prevalence of I. suis oocysts. Six faecal samples were collected in each of the farms (two from groups of 10- to 19-day-old piglets, two from groups of 20- to 29-day-old and another two from groups of 30- to 50-day-old pigs). Faecal consistency was also registered at the time of their collection. Chi-square tests were used for statistical analysis. Oocysts were more prevalent in farms with a history of neonatal isosporosis than in those without previous cases. Faecal consistency was not related to oocyst elimination. In farms with a history of clinical isosporosis, faecal samples from groups of 10- to 19-day-old piglets showed a higher prevalence of oocysts than the groups of other ages studied. There was no difference in the prevalence of oocysts between nursing and weaned piglets. Oocysts were more prevalent in faecal samples collected from dirty-cemented floors than from self-cleaning floors in the farrowing houses. Types of floor and pig management in nursery houses were not associated with the presence of oocysts in weaned pigs.

Resistance to diclazuril in field isolates of Eimeria species obtained from commercial broiler flocks in Brazil.

The efficacy of the anticoccidial drug diclazuril against field isolates of Eimeria spp. collected from broiler farms in four different sites of the South and Southeastern regions of Brazil were investigated. The effect of the drug was measured by an assessment of weight gain, lesion score and oocyst production. Two reference laboratory strains not previously exposed to diclazuril were sensitive to the drug. Two field isolates were judged to be sensitive to diclazuril, four were partly resistant and six were resistant to the drug. The response of the isolates to diclazuril varied depending upon the extent of exposure and type of drug programme in use at the farms.

Fractionation and antigenic characterization of organelles of Eimeria tenella sporozoites.

Sporozoites of Eimeria tenella were disrupted by sonication and subcellular fractions were separated by sucrose gradient ultracentrifugation. Fractions from gradients were characterized by electron microscopical appearance and their polypeptide and antigenic profiles determined by PAGE and Western blotting with antisera to sporozoites and 1st- and 2nd-generation merozoites. Fractions containing micronemes, rhoptries or membranes showed markedly different polypeptide content and antigenic reactivity. Microneme epitopes were strongly conserved between sporozoites and 2nd-generation merozoites whereas the majority of rhoptry epitopes and many membrane epitopes were sporozoite specific. The only polypeptide of sporozoites which was strongly recognized by antisera raised to 1st generation merozoites was a microneme antigen of molecular weight approximately 100 kDa.

Sequence of the gene encoding an immunodominant microneme protein of Eimeria tenella.

A heterodisperse family of antigens, previously detected on sporozoites and merozoites of Eimeria tenella, has been localised to the microneme organelles within the sporozoite. Sequencing of genomic and cDNA clones shows that the gene for this antigen family contains 4 exons separated by 3 short (519, 226 and 156 nucleotides) intervening sequences and that the predicted polypeptide from the longest open reading frame has 4 structural domains. One of these contains 5 copies of the thrombospondin-like motif, previously identified in the partial sequence of the gene, which is conserved in a variety of molecules which have been demonstrated to have adhesive properties. A second domain of the polypeptide has strong similarity to a conserved region that occurs in another group of molecules which have adhesive properties, including the alpha subunits of several integrins, complement factor Bb and a number of extracellular matrix glycoproteins. Overall the antigen resembles the thrombospondin-related anonymous protein identified in the erythrocytic stage of Plasmodium falciparum. The structure of the gene supports a role for this microneme antigen in cell-cell or cell-matrix interactions.

Sensitivity of field isolates of Eimeria acervulina to salinomycin, maduramicin, and a mixture of clopidol and methyl benzoquate in the chicken.

Lerbek was more effective than salinomycin, and salinomycin more effective than maduramicin, against field isolates of E. acervulina obtained from farms where salinomycin had been used continuously for 30 crops. Salinomycin was the most effective drug against isolates of E. acervulina from farms where various shuttle programmes had been employed. Lerbek and maduramicin were ineffective against these isolates.

Schistosomiasis mansoni in the municipality of Pedro de Toledo (Säo Paulo, Brazil) where the Biomphalaria tenagophila is the snail host. I-Prevalence in human population

Devido à escassez de dados epidemiológicos sobre esquistossomose mansônica onde Biomphalaria tenagophila é vetor foi desenvolvido em 1980 o presente trabalho, no município paulista de Pedro de Toledo. Foram examinadas fezes de 4741 pesssoas (Método de Kato-Katz) com prevalência de 22,8%; entre essas, 583 foram tratadas para a endemia anteriormente e 4158 näo medicadas; as prevalências nos dois grupos foram, respectivamente, 31,7% e 21,6%. Por investigaçäo epidemiológica constatou-se que 83,6% dos casos foram autóctones da área estudada. Prevalência dos autóctones näo tratados foram maiores no homem do que na mulher, a intensidade no último grupo foi baixa: 58,5 ovos g de fezes (média geométrica). De acordo com grupos etários, se correlacionaram bem (rs=0,745) as intensidades de infecçäo e as prevaleência. A infecçäo ocorreu, na zona rural, principalmente, durante lazer e trabalho doméstico. Somente 0,4% de 1137 moluscos foram positivos para Schistosoma mansoni. Esse índice foi, aparentemente, o mesmo em estudo de 1978 quando a prevalência humana era de 12,0%. A área estudada apresentou difernças e semelhanças epidemiológicas em relaçäo às áreas onde B. glabrata é o principal hospedeiro intermediário

Schistosomiasis mansoni in the municipality of Pedro de Toledo (São Paulo, Brazil) where the Biomphalaria tenagophila is the snail host. I--Prevalence in human population.

Due to the scarce information about the epidemiological features of schistosomiasis in which the vector is Biomphalaria tenagophila, an investigation was carried in Pedro de Toledo in 1980 where such peculiarity is observed. Stool examinations (Kato-Katz method) were performed in 4,741 individuals (22.8% positive to Schistosoma mansoni eggs) of this 583 had previously received chemotherapy and 4,158 remainders, untreated. The schistosomiasis prevalence in those two groups where respectively 31.7% and 21.6%. Epidemiological investigation showed that 83.6% were autochthonous cases from the studied area: the autochthonous prevalence rate, and the intensity of infection in the untreated autochthonous cases were higher in males than in females; the intensity in the latter untreated group was low, 58.5 eggs/g feces (geometric mean). Moreover, according to the age groups the intensity of infections correlated well (rs = 0.745) with the prevalence rates. Schistosomiasis was verified to occur mostly during the leisure time and by the use of water streams for housework in rural zone. Only 0.4% out of 1,137 snails was positive for S. mansoni cercariae, apparently unchanged from the 1978 study when the human prevalence was 12.0%. The studied area presented differences and similarities in relation to the other Brazilian areas were the main intermediate host is B. glabrata.

An immunoepidemiological study of schistosomiasis mansoni in Paraiba's Valley, Sao Paulo, Brazil.

Inquerito imunoepidemiologico foi realizado na fazenda Santa Helena, localizada no Vale do Rio Paraiba do Sul, Sao Paulo. A prevalencia de esquistossomose determinada pela reacao de imunofluorescencia foi de 25,5% e de 29,8% pela reacao intradermica. O exame coprologico revelou 10,6% de infectados, cerca de tres vezes mais do que observado no inquerito preliminar de 1977. A influencia de poliparasitismo na sensibilidade e na especificidade das reacoes imunologicas nao foi significativo. Resultados satisfatorios foram obtidos na reacao de imunofluorescencia com cortes de figado de hamster infectado com S.mansoni, tendo granuloma e ovos do parasita como antigeno