Isolation and pathogenicity of Toxoplasma gondii in naturally infected (rustic farm) pigs in southern Brazil.

This study reported a serological test for Toxoplasma gondii infection in 100 pigs from 58 rural farms in the state of Rio Grande do Sul, Brazil. Thirty-six pigs were seropositive (IFAT≥1:64). Bioassays were performed for all 36 seropositive pigs, and 17 isolates were obtained (47.2%). Seven of these isolates (41.2%) were highly pathogenic to mice, as clinical signs of acute infection were observed, and tachyzoites were found in the peritoneal exudates, livers, and lungs. The remaining 10 isolates were able to establish a chronic infection in mice, therefore, they were not highly virulent. The results of this study indicate that pork is a potential source of T. gondii transmission to humans.

Parasitism of gallus gallus (linnaeus, 1758) by species of phthiraptera on free-range chickens in the southern region of Rio Grande do Sul, Brazil / Parasitismo de Gallus Gallus (Linnaeus, 1758) por espécies de Phthiraptera em criações coloniais na região sul do Rio Grande Do Sul, Brasil

This study was conducted in order to identify the species of biting lice (order Phthiraptera: Amblycera suborders and Ischnocera) that infest free-range chickens in southern Rio Grande do Sul, Brazil. Fifty adult females from 10 farms located in 5 different municipalities were examined for ectoparasites. The chickens were euthanized and then washed with water and detergent for the collection of ectoparasites by filtration using a 150-µm mesh sieve, then separated into pellet and supernatant, which were preserved in ethanol 70% for the screening procedures and identification. A total of 19,437 lice were examined, presenting the following breakdown by species: Menopon gallinae (85.9%), Goniodes dissimilis (6.1%), Lipeurus caponis (3.0%), Goniocotes gallinae (2.5%), Menacanthus pallidus (2.1%) and Menacanthhus stramineus (0.1%). It was found that all the chickens examined were parasitized by one or more species of Phthiraptera, the multiple and moderate level of infestation (101 to 1,000 lice/chicken) being the most frequent. M. gallinae was the most frequent and abundant species (100% of the chickens parasitized and an average of 334.1 lice/chicken). The degree of infestation of chickens varied among the farms, averaging 41.2 to 680 lice/chicken.

Este estudo foi realizado com o objetivo de conhecer os piolhos (ordem Phthiraptera: Subordens Amblycera e Ischnocera) infestantes de galinhas de criações coloniais no Sul do Rio Grande do Sul. Cinquenta fêmeas adultas foram examinadas, de 10 propriedades rurais localizadas em 5 diferentes municípios. As aves foram eutanasiadas e posteriormente lavadas com água e detergente para coleta dos ectoparasitos através de filtragem por passagem em tamis com malha de 150 µm, separando-se em sedimento e sobrenadante, os quais foram preservados em etanol 70% até os processos de triagem e identificação. Cerca de 19.437 piolhos foram examinados e apresentaram a seguinte composição específica: os resultados indicam que a fauna de Phthiraptera em galinhas caipiras na região é composta por: Menopon gallinae (85,9%), Goniodes dissimilis (6,1%), Lipeurus caponis (3,0%), Goniocotes gallinae (2,5%), Menacanthus pallidus (2,1%) e Menacanthus stramineus (0,1%). Constatou-se que todas as aves examinadas estavam parasitadas por uma ou mais espécies de Phthiraptera, com predomínio de infestações múltiplas e moderadas (101 a 1.000 piolhos/ave). M. gallinae é a espécie mais prevalente e abundante (100% das aves parasitadas e média de 334,1 espécimes/ave). O grau de infestação das aves variou entre as propriedades, com médias de 41,2 a 680 piolhos/ave.

Development and evaluation of a quantitative PCR assay for detection of Hepatozoon sp.

With the aim to improve current molecular diagnostic techniques of Hepatozoon sp. in carnivore mammals, we developed a quantitative PCR (qPCR) assay with SYBR Green I((R)). The method, consisting of amplification of a 235bp fragment of the 18S rRNA gene, is able to detect at least 0.1fg of parasite DNA. Reproducible quantitative results were obtained over a range of 0.1ng-0.1fg of Hepatozoon sp. DNA. To assess the performance of the qPCR assay, DNA samples from dogs (140) and cats (50) were tested with either standard PCR or qPCR. Positive samples were always confirmed by partial sequencing of the 18S rRNA gene. Quantitative PCR was 15.8% more sensitive than standard PCR to detect H. canis in dogs. In cats, no infections were detected by standard PCR, compared to two positives by qPCR (which were infected by H. canis as shown by sequencing).

New molecular data on mammalian Hepatozoon species (Apicomplexa: Adeleorina) from Brazil and Spain.

Molecular techniques were used to examine the phylogenetic relationships among Hepatozoon species isolated from 13 foxes and 15 opossums from Brazil, and from 15 dogs, 20 foxes, 45 rodents, and 330 domestic cats from Spain. Hemogregarine infection was confirmed by amplification of the 18S rRNA gene and later sequencing. No hemogregarine infections were found in opossums. The prevalence of Hepatozoon in canids ranged from 26.6% (symptomatic domestic dogs) to 90% (Spanish foxes). Four different H. canis genotypes were detected, as well as an H. americanum-related protozoan (97% identical to the USA strain). Two Spanish cats were parasitized by a Hepatozoon species (0.6% prevalence) that showed 96% sequence identity to H. canis. DNA amplification assays performed on Spanish rodents showed 2 bank voles (Clethrionomys glareolus) to be infected by a Hepatozoon species (4.44% prevalence) with 95% sequence identity to Hepatozoon sp. from cats. Phylogenetic analysis showed Hepatozoon to be a monophyletic genus, in which species from carnivorous mammals (Hepatozoon sp. from cats, H. americanum and H. canis) appear as a sister lineage of that of lower vertebrates and rodents. This association suggests that H. americanum evolved in ticks and carnivores (either canids, or felids, or both) rather than in other ectoparasites and other types of mammal.

Detection of antibodies to Neospora caninum in two species of wild canids, Lycalopex gymnocercus and Cerdocyon thous from Brazil.

Domestic dog (Canis domesticus) and the coyote (Canis latrans) are the only known definitive hosts for the protozoan Neospora caninum that causes abortion in dairy cattle. In the present study, antibodies to N. caninum were sought in three species of wild canids, Cerdocyon thous, Lycalopex gymnocercus and Dusicyon vetulus from Brazil. Antibodies to N. caninum were assayed by the indirect fluorescent antibody test (IFAT) and the Neospora agglutination test (NAT). N. caninum antibodies were found in five of 12 L. gymnocercus with IFAT titers of 1:50 in three, 1:100 in one, and 1:1600 in one, and NAT titers of 1:40, 1:80, 1:160, 1:320, and 1:640 in five animals. Antibodies to N. caninum were found in four of 15 C. thous with IFAT titers of 1:50 in one, and 1:100 in three, and NAT titer of 1:40 in one animal. All 30 D. ventulus were seronegative by IFAT and NAT.

Utilizaçäo da forrageira Melinis minutiflora (capim-gordura) no controle alternativo do carrapato Boophilus microplus / Utilization of fodder Melinis minutiflora (molasses grass) in the alternative control of tick Boophilus microplus

O parasitismo de bovinos pelo carrapato Boophilus microplus torna-se cada vez maior, pela crescente necessidade de produçäo em áreas menores, o que favorece as reinfestaçöes. Como a pastagem exerce papel importante na fase de vida livre das larvas e ovos, os autores realizaram o presente trabalho para verificar a capacidade do capim-gordura (Melinis minutiflora) como fator limitante da populaçäo de carrapatos. O estudo demonstrou a viabilidade do uso desse capim no controle alternativo do carrapato, os autores recomendando novos estudos complementares.