Infections by the protozoan parasite Toxoplasma gondii are widely prevalent in humans and animals in Brazil. The burden of clinical toxoplasmosis in humans is considered to be very high. The high ...prevalence and encouragement of the Brazilian Government provides a unique opportunity for international groups to study the epidemiology and control of toxoplasmosis in Brazil. Many early papers on toxoplasmosis in Brazil were published in Portuguese and often not available to scientists in English-speaking countries. In the present paper we review prevalence, clinical spectrum, molecular epidemiology, and control of T. gondii in humans and animals in Brazil. This knowledge should be useful to biologists, public health workers, veterinarians, and physicians. Brazil has a very high rate of T. gondii infection in humans. Up to 50% of elementary school children and 50–80% of women of child-bearing age have antibodies to T. gondii. The risks for uninfected women to acquire toxoplasmosis during pregnancy and fetal transmission are high because the environment is highly contaminated with oocysts. The burden of toxoplasmosis in congenitally infected children is also very high. From limited data on screening of infants for T. gondii IgM at birth, 5–23 children are born infected per 10 000 live births in Brazil. Based on an estimate of 1 infected child per 1000 births, 2649 children with congenital toxoplasmosis are likely to be born annually in Brazil. Most of these infected children are likely to develop symptoms or signs of clinical toxoplasmosis. Among the congenitally infected children whose clinical data are described in this review, several died soon after birth, 35% had neurological disease including hydrocephalus, microcephaly and mental retardation, 80% had ocular lesions, and in one report 40% of children had hearing loss. The severity of clinical toxoplasmosis in Brazilian children may be associated with the genetic characteristics of T. gondii isolates prevailing in animals and humans in Brazil.
Recent studies found that isolates of
Toxoplasma gondii from Brazil were biologically and genetically different from those in North America and Europe. However, to date only a small number of ...isolates have been analysed from different animal hosts in Brazil. In the present study DNA samples of 46
T. gondii isolates from cats in 11 counties in São Paulo state, Brazil were genetically characterised using 10 PCR restriction fragment length polymorphism markers including
SAG1,
SAG2,
SAG3,
BTUB,
GRA6, c22-8, c29-2, L358,
PK1 and Apico. An additional marker, CS3, that locates on chromosome VIIa and has previously been shown to be linked to acute virulence of
T. gondii was also used to determine its association to virulence in mice. Genotyping of these 46 isolates revealed a high genetic diversity with 20 genotypes but no clonal Type I, II or III lineage was found. Two of the 46 isolates showed mixed infections. Combining genotyping data in this study with recent reported results from chickens, dogs and cats in Brazil (total 125 isolates) identified 48 genotypes and 26 of these genotypes had single isolates. Four of the 48 genotypes with multiple isolates identified from different hosts and locations are considered the common clonal lineages in Brazil. These lineages are designated as Types BrI, BrII, BrIII and BrIV. These results indicate that the
T. gondii population in Brazil is highly diverse with a few successful clonal lineages expanded into wide geographical areas. In contrast to North America and Europe, where the Type II clonal lineage is overwhelmingly predominant, no Type II strain was identified from the 125 Brazil isolates. Analysis of mortality rates in infected mice indicates that Type BrI is highly virulent, Type BrIII is non-virulent, whilst Type BrII and BrIV lineages are intermediately virulent. In addition, allele types at the CS3 locus are strongly linked to mouse-virulence of the parasite. Thus,
T. gondii has an epidemic population structure in Brazil and the major lineages have different biological traits.
Toxoplasma gondii infections are common in humans and animals worldwide. Domestic free-range chickens (Gallus domesticus) are excellent sentinels of environmental contamination with T. gondii oocysts ...because they feed on the ground. Chickens can be easily infected with T. gondii; however, clinical toxoplasmosis is rare in these hosts. Chickens are comparatively inexpensive and thus are good sentinel animals for T. gondii infections on the farms. Here, the authors reviewed prevalence, the persistence of infection, clinical disease, epidemiology and genetic diversity of T. gondii strains isolated from chickens worldwide for the past decade. Data on phenotypic and molecular characteristics of 794 viable T. gondii strains from chickens are discussed, including new data on T. gondii isolates from chickens in Brazil. This paper will be of interest to biologists, epidemiologists, veterinarians and parasitologists.
Study objectives were to evaluate the effects of feeding rumen-protected Met (RPM) in pre- and postpartum total mixed rations (TMR) on health disorders and the interactions of health disorders with ...lactation and reproductive performance. Multiparous Holstein cows 470; 235 cows at University of Wisconsin (UW) and 235 cows at Cornell University (CU) were enrolled at approximately 4 wk before parturition and housed in close-up dry cow (n = 6) and replicated lactation pens (n = 16). Pens were randomly assigned to treatment diets (pre- and postpartum, respectively): (1) control (CON): basal diet = 2.30% and 2.09% Met as % of metabolizable protein (MP) (UW) or 2.22% and 2.19% Met as % of MP (CU); (2) RPM: basal diet fed with RPM with 2.83% and 2.58% Met (Smartamine M, Adisseo Inc.; 12 g prepartum and 27 g postpartum), as % of MP (UW) or 2.85% and 2.65% Met (Smartamine M; 13 g prepartum and 28 g postpartum), as % of MP (CU). Total serum Ca was evaluated at the time of parturition and on d 3 ± 1 postpartum. Daily rumination was monitored from 7 d before parturition until 28 d postpartum. Health disorders were recorded during the experimental period until the time of first pregnancy diagnosis (32 d after timed artificial insemination; 112 ± 3 d in milk). Uterine health was evaluated on d 35 ± 3 postpartum. Time to pregnancy and herd exit were evaluated up to 350 d in milk. Treatment had no effect on the incidence of most health disorders and did not alter daily rumination. Cows fed RPM had reduced subclinical hypocalcemia (13.6 vs. 22%; UW only) on day of parturition relative to CON. Percentage of cows culled (13.1 vs. 19.3%) and hazard of herd exit due to culling hazard ratio = 0.65, 95% confidence interval (CI): 0.42–1.02 tended to be reduced for cows fed RPM compared with CON. Moreover, cows fed RPM had greater milk protein concentration and protein yield overall, although retrospective analysis indicated that RPM only significantly increased protein yield in the group of cows with one or more health disorders (1.47 vs. 1.40 kg/d), not in cows without health disorders (1.49 vs. 1.46 kg/d) compared with CON. Overall, treatment had no effect on pregnancy per timed artificial insemination; however, among cows with health disorders, those fed RPM had reduced time to pregnancy compared with CON (hazard ratio = 0.71, 95% CI: 0.53–0.96). Thus, except for subclinical hypocalcemia on the day of parturition, feeding RPM in pre- and postpartum TMR did not reduce the incidence of health disorders, but our retrospective analysis indicated that it lessened the negative effects of health disorders on milk protein production and time to pregnancy.
Modeling and experimental analyses were carried out to investigate current and temperature distributions under typical spark plasma sintering (SPS) conditions. The simulation utilized two sample ...materials with widely differing electrical conductivities, alumina and copper. Current and heat generation gradients were evaluated in the radial and axial directions for both cases. Radial gradients result in significant differences in temperature between the surface of the graphite die and its center, in agreement with experimental measurements. Axial gradients are shown to influence the homogeneity of the product.
Species of the genus Leishmania parasitize mammals and have life cycles that alternate between vertebrate and invertebrate hosts. Most species develop in a hematophagous arthropod and infect a ...specific vertebrate host that may belong to diverse orders and families. Visceral leishmaniasis is a chronic zoonosis with a wide geographic distribution, affecting 350 million people globally, mostly in areas with a high risk of infection. In Brazil, this disease not only has a high incidence but is also expanding to new areas, both in urban centers and rural areas, including territories with tribal communities, due to increasing human intervention. The objective of this study was to perform cathepsin L-like gene-based molecular diagnosis of Leishmania infantum in the indigenous Tapirapé ethnic group in the state of Mato Grosso. From the 372 individuals assessed, only 0.8% (3/372) tested positive for L. infantum, all from the same village (Urubu Branco). Despite the small number of infected individuals, this study demonstrates the first human cases of Leishmania infantum infection in this population, suggesting the need for regular monitoring of visceral leishmaniasis in the area and leading to a broad discussion on the planning and implementation of public health measures for the indigenous population, while respecting their distinctive territories and culture.
A study was conducted to assess the breed resistance against nematode infections in Santa Ines, Ile de France and Suffolk male lambs over a 9-month period in São Paulo state, Brazil. Lambs were born ...during the winter (year 2000) and were weaned at 2 months of age. The animals were then housed and treated with anthelmintics to eliminate natural infections by gastrointestinal nematodes. In late October 2000, lambs were placed in a paddock, where they stayed until August of the following year. Fecal and blood samples were taken from each animal every 2 weeks. On the same day, a pasture sample was collected to determine the number of infective larvae on the herbage. To prevent deaths, individual treatment with anthelmintics was provided to lambs with fecal egg counts (FEC) higher than 4000 eggs per gram (EPG) or with a packed cell volume (PCV) lower than 21%. In August 2001, all animals were slaughtered and the worms present in samples of the gastrointestinal contents were identified and counted. Most of the Suffolk and Ile de France sheep received three to six anthelmintic treatments over a period of 7 months, while most of the Santa Ines were not treated. Reductions in PCV and plasma protein values associated with high FEC and worm burdens were recorded, particularly, in Suffolk and Ile de France lambs.
Haemonchus contortus and
Oesophagostomum columbianum burdens and number of nodular lesions caused in the large intestine by
O. columbianum larvae were significantly lower in Santa Ines sheep. All three breeds showed similar
Trichostrongylus colubriformis worm burdens
. The relative resistance of Santa Ines young male sheep was superior to that of Suffolk and Ile de France sheep.
In spite of a wide host range and a world wide distribution,
Toxoplasma gondii has a low genetic diversity. Most isolates of
T. gondii can be grouped into two to three lineages. Type I strains are ...considered highly virulent in outbred laboratory mice, and have been isolated predominantly from clinical cases of human toxoplasmosis whereas types II and III strains are considered avirulent for mice. In the present study, 17 of 25 of the
T. gondii isolates obtained from asymptomatic chickens from rural areas surrounding São Paulo, Brazil were type I. Antibodies to
T. gondii were measured in 82 chicken sera by the modified agglutination test using whole formalin-preserved tachyzoites and mercaptoethanol and titres of 1:10 or more were found in 32 chickens. Twenty-two isolates of
T. gondii were obtained by bioassay in mice inoculated with brains and hearts of 29 seropositive (≥1:40) chickens and three isolates were obtained from the faeces of cats fed tissues from 52 chickens with no or low levels (<1:40) of antibodies. In total, 25 isolates of
T. gondii were obtained by bioassay of 82 chicken tissues into mice and cats. All type I isolates killed all infected mice within 4 weeks whereas type III isolates were less virulent to mice. There were no type II strains. Tissue cysts were found in mice infected with all 25 isolates and all nine type I isolates produced oocysts. Infected chickens were from localities that were 18–200
km apart, indicating no common source for
T. gondii isolates. This is the first report of isolation of predominantly type I strains of
T. gondii from a food animal. Epidemiological implications of these findings are discussed.
Until recently,
Toxoplasma gondii was considered clonal with very little genetic variability. Recent studies indicate that
T. gondii isolates from Brazil are genetically and biologically different ...from
T. gondii isolates from USA and Europe. In the present study, we retyped 151 free range chicken isolates from Brazil including 117 newly isolated samples from 11 geographically areas (Alagoas, Bahia, Ceará, Maranhão, Paraná, Pernambuco, Rio de Janeiro, Rio Grande do Norte, São Paulo, Sergipe, and Rondonia) and 34 previously reported isolates from the very north (Pará) and the very south (Rio Grande do Sul). Ten PCR-RFLP markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico were used to genotype all isolates. Overall analysis of 151
T. gondii isolates revealed 58 genotypes. Half (29/58) of these genotypes had single isolate and the other half of the genotypes were characterized with two or more isolates. Only 1 of 151 isolates was clonal Type I strain and 5 were clonal Type III strains. Two isolates had mixed infections. Clonal Type II strain was absent. One strain was Type II at all loci, except BTUB. The results confirm high genetic diversity of
T. gondii isolates from Brazil.
•Isolation and genotyping of T. gondii from free-range chickens from Brazil are perfomed.•Isolates were obtained from birds with a minimum IFAT titer of 1:256.•The five isolates corresponded to four ...PCR-RFLP genotypes, one reported for the first time.•The most prevalent Brazilian clonal lineage BrI (African 1) also circulates in the studied region.•Microsatellite study emphasizes the great diversity of Brazilian T. gondii isolates.
Toxoplasma gondii is a protozoan with worldwide distribution that infects warm-blooded vertebrates, including humans. Toxoplasma is considered to be monospecific, but three classical clonal lineages (Types I–III) have been described, especially for isolates from North America and Europe. However, recently, several studies have shown that many isolates, particularly from South America, are different from the classic types and highly diverse, with the presence of specific clonal lineages and non-archetypal genotypes. In order to isolate and genotypically characterize T. gondii, 60 free-range naturally infected chickens (Gallus domesticus) from four municipalities on São Luis island, state of Maranhão, Brazil, were first serologically screened for IgG anti-T. gondii antibodies by means of the immunofluorescent antibody test (IFAT≥1:16). Heart and brain samples from seropositive chickens were bioassayed in mice. The isolates obtained from bioassaying were genotyped by means of PCR-RFLP (restriction fragment length polymorphism) using 11 markers and by microsatellites (MS) using 15 markers. The frequency of anti-T. gondii antibodies in the chickens examined was 25.0% (15/60). Five isolates of T. gondii were obtained and named TgCkBrMA1 to 5. Four genotypes were described. One of them is reported for the first time. No classic clonal lineages of types I, II or III were found, but the Brazilian clonal lineage BrI was identified. MS analysis revealed five genotypes. The results corroborate studies already developed in other regions of Brazil, thus indicating that T. gondii has high genetic diversity in Brazil.
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