Jerônimo Lopes Ruas

Análise da eficácia de acaricidas sobre o carrapato Boophilus microplus, durante a última década, na região sul do Rio Grande do Sul

A regiao sul do Rio Grande do Sul caracteriza-se por uma bovinocultura com predominio de racas europeias, tanto para producao de carne, quanto de leite. Essa regiao e considerada area marginal de ocorrencia do carrapato Boophilus microplus, cujo parasitismo ocorre entre final de setembro e meados de maio devido as baixas temperaturas do inverno. No entanto, as perdas causadas por esse parasito sao elevadas, o que tem sido agravadas pela selecao de populacoes de carrapatos resistentes aos acaricidas. O presente trabalho teve como objetivo estudar a situacao de sensibilidade/resistencia do carrapato bovino, assim como a dinâmica de uso dos diferentes grupos acaricidas disponiveis no mercado, na regiao sul do Rio Grande do Sul, na ultima decada. Durante o periodo foram avaliadas amostras de carrapatos provenientes de 124 propriedades, de 14 municipios da regiao. Em cada propriedade foram coletadas teleoginas e informacoes relativas ao manejo. No Laboratorio de Parasitologia do Instituto de Biologia da UFPel, foi realizado teste de imersao de teleoginas. Observou-se que durante o primeiro trienio os produtos mais utilizados eram a base de piretroide, determinando uma selecao de populacoes resistentes a esse principio ativo. No terceiro trienio os produtos a base de amitraz dominaram o mercado, ocorrendo tambem selecao de populacoes resistentes. No primeiro trienio, todas as populacoes de carrapato analisadas eram sensiveis ao amitraz (indice de eficacia = 95%), enquanto que, ao final do estudo, no terceiro trienio, esse indice de eficacia foi detectado em apenas 79% das populacoes estudadas. Foram detectadas falhas de manejo na regiao, como numero de aplicacao superior a seis por ano, aplicacao de acaricida somente quando visualizadas as formas adultas e uso exclusivo de acaricidas para o controle do carrapato, que predispoem a selecao de populacoes resistentes.

Molecular characterization of arthropod-borne hematozoans in wild mammals from Brazil, Venezuela and Spain

A survey of Babesia, Theileria and Hepatozoon was conducted in wild mammals, including the capybara (Hydrochaeris hydrochaeris; n = 14) from Brazil, the jaguar (Panthera onca; n = 2) and crab-eating raccoon (Procyon cancrivorus; n = 4) from Venezuela, and the red deer (Cervus elaphus; n = 70), red squirrel (Sciurus vulgaris; n = 5) and Eurasian pine marten (Martes martes; n = 3) from Spain. Diagnostic procedures included both microscopy and molecular methods (PCR and sequencing of the 18S rRNA gene). Microscopic examination of blood smears revealed no hematozoan infections — unlike the molecular analyses. Nine Brazilian capybaras were found to be infected with Hepatozoon canis (prevalence 64%), two of which were coinfected with a previously unknown babesid (prevalence 14%) loosely related to Theileria equi (90% 18S rRNA gene similarity according to BLAS® analysis). One jaguar and one crab-eating raccoon from Venezuela were infected by H. canis. Four of the red deer were infected with theilerids (5.7% prevalence), two with Theileria sp. and two with T. annulata. One red squirrel and three pine martens were infected with Hepatozoon sp. The isolate form the red squirrel was phylogenetically related to Hepatozoon sp. reported in Spanish bank voles, whereas those infecting the pine martens were related to Hepatozoon felis reported in Spanish cats. In conclusion, the molecular findings show that some non-canid mammals are carriers of H. canis in South America, while red deer may carry T. annulata in Europe. Small mammals in Europe appear to be unlikely hosts of H. canis and H. felis.

HELMINTOS DO CACHORRO DO CAMPO, Pseudalopex gymnocercus (FISCHER, 1814) E DO CACHORRO DO MATO, Cerdocyon thous (LINNAEUS, 1766) NO SUL DO ESTADO DO RIO GRANDE DO SUL, BRASIL

2 ABSTRACT:- RUAS, J.L.; MULLER, G.; FARIAS, N.A.R.; GALLINA, T.; LUCAS, A.S.; PAPPEN, F.G.; SINKOC, A.L.; BRUM, J. G.W. (Helminths of Pampas fox Pseudalopex gymnocercus (Fischer, 1814) and of Crab-eating fox Cerdocyon thous (Linnaeus, 1766) in the Southern of the State of Rio Grande do Sul, Brazil). Helmintos do Cachorro do campo Pseudalopex gymnocercus (Fischer, 1814) e do Cachorro do mato Cerdocyon thous (Linnaeus, 1766) no sul do estado do Rio Grande do Sul, Brasil. Revista Brasileira de Parasitologia Veteri- naria, v. 17, n. 2, p. 87-92, 2008. Laboratorio Regional de Diagnostico, Faculdade de Veterinaria, Universidade Federal de Pelotas, Rio Grande do Sul, Brasil. Caixa Posta 354, CEP.: 96.010-900. E-mail: ruas@ ufpel.edu.br Forty wild canids were captured by live trap at Municipalities of Pedro Osorio and Pelotas in Southern of the State of Rio Grande do Sul and they were transported to the Parasitology Laboratory at the Universidade Federal de Pelotas. After they were posted, segments of intestinal, respiratory and urinary tracts and liver were separated and examined. Animal skulls were used for taxonomic identification. Of forty wild animals trapped, 22 (55%) were Pseudalopex gymnocercus and 22 (55%) Cerdocyon thous. The most prevalent nematodes were: Ancylostoma caninum (45.4 in P. gymnocercus and 22.2% in C. thous), Molineus felineus (9.9 in P. gymnocercus and 5.6% in C. thous), Strongyloides sp. (22.7 in P. gymnocercus and 16.7% in C. thous), Trichuris sp. (13.6 in P. gymnocercus and 11.1% in C. thous), and Capillaria hepatica (13.6 in P. gymnocercus and 5.5 % in C. thous). The trematodes observed were: Alaria alata (36.4 in P. gymnocercus and 50.0% in C. thous), and Asthemia heterolecithodes in 5.6% C. thous. Cestodes were identified as Spirometra sp. (61.1 % in C. thous and 54.5 in P. gymnocercus), Diphyllobothriidae, (81.8 in P. gymnocercus and 77.8 % in C. thous) and an Acantocephala of the genus Centrorhynchus was also observed in 5.6% of C. thous only. These results indicated the helminths fauna in wild canids from the studied area.

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.

Occurrence of antibodies to Toxoplasma gondii in water buffaloes and meat cattle in Rio Grande do Sul State, southern Brazil

Serum samples from 169 water buffaloes and 121 beef cattle were analyzed for antibodies to T. gondii by an indirect fluorescent antibody test (IFAT). Positive results were obtained in 27.2% of water buffaloes and 17.4% of cattle. Statistical analysis indicated significant differences between the prevalence in cattle and buffalo (p ≤ 0.05). The highest titres found in positive animals were 1:256 (buffaloes) and 1:64 (cattle). In both bovine species, toxoplasmosis frequency in young animals (less than 2 years old) was lower compared to older individuals, although the differences seen in cattle were not statistically significant.

Fasciolose aguda em bovinos no Sul do Brasil

Descrevem-se os aspectos epidemiologicos e patologicos de um surto de fasciolose aguda diagnosticado em bovinos na regiao sul do Rio Grande do Sul. De um lote de 70 vacas de tres anos de idade 15 apresentaram perda de peso 30-40 dias antes da paricao. Dessas, 10 vacas abortaram e 5 morreram. Os sinais clinicos caracterizaram-se por diarreia, fraqueza, anemia discreta e ictericia. Na necropsia havia liquido escuro na cavidade abdominal. Na cavidade toracica havia fibrina e coagulos de sangue aderidos ao pericardio e pulmoes, principalmente nos lobos diafragmaticos. O figado estava aumentado de tamanho e a superficie capsular estava irregular com areas claras e petequias. A superficie de corte estava irregular, firme e edematosa e podiam ser observadas estrias hemorragicas atraves do parenquima. Areas de fibrose e trombos esbranquicados ocluindo vasos sanguineos foram, tambem, observados. Os figados das 10 vacas que nao morreram foram condenados no abate por lesoes de fasciolose similares as observadas na necropsia. Microscopicamente, o figado apresentava areas de necrose de coagulacao, focos de hemorragia acentuada e desorganizacao do parenquima com acentuada infiltracao de neutrofilos e eosinofilos. Havia, ainda, fibrose e hiperplasia de celulas de ductos biliares. Formas imaturas de Fasciola hepatica foram observadas no parenquima rodeadas por hepatocitos em degeneracao, neutrofilos e eosinofilos, e hemorragia. O surto ocorreu em uma propriedade localizada em uma area endemica para a fasciolose, embora a forma aguda da enfermidade nao seja frequente em bovinos nesta regiao. E provavel que as vacas tenham se infectado pelas metacercarias liberadas do hospedeiro intermediario no final do outono ou no inicio da primavera na resteva de arroz onde foram colocadas antes da paricao. Embora mortalidade em bovinos devido a fasciolose seja infrequente, surtos podem ocorrer e a utilizacao de fasciolicidas eficientes para controlar as formas imaturas ou adultas deste parasita devem ser administradas aos bovinos para evitar eventuais perdas economicas.

Eficácia de vermífugos à base de avermectinas e milbemicinas utilizados há cinco anos em uma criação de eqüinos

Avaliou-se a eficacia do controle parasitario com anti-helminticos (AH) de largo espectro usados ha mais de cinco anos, em um plantel equino da raca puro-sangue ingles, sob manejo semi-intensivo. Os animais foram tratados com Ivermectin (Eqvalanâ) e Moxidectin (Equestâ), por via oral. Durante o estudo, o numero de ovos por grama de fezes (opg) manteve-se zero na maioria dos animais.

Cerebral equine hydatidosis in Southern Brazil

Equine cerebral hydatid disease is described in a 7-year-old, crossbred, female horse. Clinical signs were characterized by circling gait, pressing of head against fences or objects and motor incoordination. On gross examination of the brain the hemispheres were swollen, mainly the left one. On transversal sections, a 5cm X 7cm fluid-filled cyst was observed within the lateral ventricle of the left hemisphere. The cyst extended from the parietal to the occipital lobe, and compressed the third ventricle. There was also marked mid line deviation. Histologically, the brain lesion adjacent to the cyst, was characterized by a piogranulomatous process and vacuolization of neuropil. A diagnosis of equine hydatidosis caused by Echinococcus granulosus was made on the basis of the morphometric features of protoscolices hooks.

Rhinonyssus sphenisci (Acari: Rhinonyssidae) in Magellanic Penguin ( Spheniscus magellanicus )

Nasal mites occur in different groups of birds, but little is known about their diversity associated with seabirds. The aim of this study was to verify the presence of nasal mites in the Magellanic Penguin (Spheniscus magellanicus), and to study their parasitological indices. For that purpose, the nasal cavity of 99 Magellanic Penguin found in the southern coast of Rio Grande do Sul, Brazil, was dissected and examined. Rhinonyssus sphenisci (Rhinonyssidae) occurred in 17 hosts (17.2%) with mean intensity of 11.52 mites/host. There were no significant differences in prevalence and mean intensity of infection between male and female hosts. Rhinonyssus sphenisci had already been reported in S. magellanicus; however, there had been no information on parasitological indices. Therefore, this study reported infection levels of R. sphenisci in S. magellanicus.

Infection Rates of Orthohalarachne attenuata and Orthohalarachne diminuata (Acari: Halarachnidae) in Arctocephalus australis (Zimmermann, 1783) (Pinipedia: Otariidae)

ABSTRACT:  Halarachnidae consists of nasal mites that parasitize pinnipeds. The respiratory tracts of 22 Arctocephalus australis (South American fur seal) were examined for the presence of mites and to study their parasitological indices. Of these, 15 hosts (68.2%) were infected with Orthohalarachne attenuata, 5 of which (22.7%) were coinfected with Orthohalarachne diminuata. A moderate to severe infection by O. attenuata was observed in 27.3% of the hosts, and by O. diminuata in 9.1%. Co-infection occurred in all O. diminuata–positive hosts. No significant differences for Halarachnidae prevalence were found between male and female hosts. Mite infections of the respiratory system by Otariidae are often reported; however, further studies should be conducted to better understand host–parasite relationships and possible pathogeneses caused by these infections.