Flores, Eduardo F.; Ridpath, Julia F.; Weiblen, Rudi; Vogel, Fernanda S. F.; and Gil, Laura H.V.G., "Phylogenetic analysis of Brazilian bovine viral diarrhea virus type 2 (BVDV-2) isolates: evidence for a subgenotype within BVDV-2" (2002 AbstractPhylogenetic analysis divides bovine viral diarrhea viruses (BVDV) into two different genotypes (BVDV1 and BVDV2). BVDV1 strains have been further subdivided into two to 11 subgenotypes. Phylogenetic analysis of BVDV2 isolates, however, has not been able to identify discrete subgenotypes. In this study, we identified six South American BVDV2 strains and one North American BVDV2 strain that cluster to a separate genetic group within BVDV2, thus representing a distinct subgenotype. The 5% untranslated region (UTR) sequence homology between these six strains and other BVDV2 from North America, Europe and Asia (81.7%) is lower than the homology used to segregate BVDV1 into BVDV1a and BVDV1b (83.6%). Most nucleotide differences observed between the two subgroups of BVDV2 were concentrated in two regions, which also harbor most of the differences seen between BVDV1a and BVDV1b. To determine if this segregation was real, an additional analysis was performed comparing NS2/3 sequences. Analysis of a conserved sequence located between nucleotides 6670 and 7186 of the NS2/3 coding region also segregated these isolates to a separate group. The sequence homology between the two subgroups (86.3%) was higher than the homology in the 5%UTR (81.7%), with mean sequence homologies of 91 and 87.2% within the proposed subgroups. In contrast to the 5%UTR, alignment of the NS2/3 sequences revealed nucleotide differences distributed across the region. These results demonstrate that BVDV2 isolates cluster to two genetically distinct subgroups within BVDV2. The differences in both the 5%UTR and NS2/3 are consistent and justify this segregation. We suggest that BVDV2 may thereafter be subgenotyped into BVDV2a and BVDV2b. The existence of subgroups within the BVDV2 genotype with genetic heterogeneity similar to that seen among BVDV1 subgroups argues against BVDV2 isolates arising from BVDV1 in a recent evolutionary event. Unless the evolutionary clocks for BVDV1 and BVDV2 isolates tick along at different rates, these results indicate that BVDV2 have existed as long as BVDV1.

A infecção pelo vírus da Diarréia V A infecção pelo vírus da Diarréia V A infecção pelo vírus da Diarréia V A infecção pelo vírus da Diarréia V A infecção pelo vírus da Diarréia Viral Bovina (BVDV) In addition to variable levels of positive serology in beef and dairy cattle, BVDV antibodies have been occasionally detected in swine, wild boars, goats, cervids and water buffaloes. BVDV infection has been diagnosed in aborted fetuses, buffy coats of persistently infected (PI) animals, clinical specimens from animals suffering from different clinical syndromes, semen of bulls of artificial insemination (AI) centers, in healthy fetuses and in commercial fetal bovine serum and/or cultured cells. About 50 isolates have been genetically and/or antigenically characterized up to date, whilst roughly an equivalent number of isolates awaits characterization. Most of the characterized isolates belong to BVDV-1 genotype, non-cytopathic (NCP) biotype, yet some BVDV-2 (and some CP BVDV) have been identified as well. Brazilian BVDV isolates display a high antigenic variability and are markedly different from North American vaccine strains. A few inactivated, polyvalent vaccines are currently licensed in the country, yet vaccination is still incipient in many regions: only about 2.5 million doses were marketed in 2003. The low serological cross-reactivity between vaccine strains and field isolates has recently stimulated national industries to develop vaccines containing Brazilian BVDV-1 and BVDV-2 strains. The overall knowledge about BVDV infection in Brazil has grown considerably in the last years, due to an increasing number of laboratories performing diagnosis and research. Studies on the pathogenesis, serological and molecular epidemiology and production of reagents for diagnosis have contributed decisively for the recent growing knowledge on BVDV infections in the country.

Gastrointestinal nematodes resistant to anthelmintics have been reported in several regions of Brazil, and they may be associated with economic losses for the cattle industry. This study aimed to evaluate the resistance status of gastrointestinal nematodes from naturally infected beef cattle to several commercially available anthelmintics, as well as to test the efficacy of combinations of anthelmintics against multi-resistant gastrointestinal nematodes. Ten farms located in Rio Grande do Sul state were selected by: farmers' consent; extensive raising system; availability of calves aged from 7 to 9 months naturally infected by gastrointestinal nematodes; absence of anthelmintic treatment for 60 days before the study; and presence of 70–100 calves or more of both genders with ≥200 eggs per gram of feces (EPG) (sensitivity of 50 EPG). These calves were distributed into 10 groups (of 7–10 animals) per farm and treated with ivermectin, doramectin, eprinomectin, fenbendazole, closantel, nitroxynil, disophenol, levamisole, albendazole, or moxidectin. Feces were collected 2 days before treatment and 14 days after treatment. Additional groups of 7–10 calves were used to test six different two-drug combinations at four of the studied farms. In general terms, fenbendazole was the most effective drug, followed by levamisole, disophenol, and moxidectin. However, parasite resistance to multiple drugs was found in all herds, especially in the genera Cooperia spp., Trichostrongylus spp., and Haemonchus spp.. Some of the two-drug combinations were effective against nematode populations identified as resistant to the same compounds when used as single drugs. The most effective combinations were moxidectin + levamisole, doramectin + fenbendazole, and levamisole + closantel. In this study, parasites resistant to the main commercially available anthelmintics were found in all herds, and some combinations of two active components belonging to different chemical groups were effective against multi-drug resistant gastrointestinal nematodes.

RESUMO O objetivo deste estudo foi avaliar o efeito in vivo e in vitro do óleo de citronela (Cymbopogon nardus (L.) Rendle) no carrapato de bovinos (Boophilus microplus). O óleo foi obtido de folhas frescas pelo processo de destilação e o rendimento foi de 0,7%. Para as experimentações in vitroforam usadas sete (0; 0,5; 1,0; 10,0; 25,0; 50,0; 100,0%) e nove (0,1; 0,25; 0,5; 1,0; 2,0; 10,0; 25,0; 50,0; 100%) concentrações de óleo de citronela, sendo testadas em fêmeas ingurgitadas. A eficácia observada foi de 0; 44,2; 92,1; 85,6; 87,8; 87,0; 88,9 e de 0,7; 2,8; 51,6; 79,3; 81,0; 87,1; 86,7; 89,5%, respectivamente 0.7%. Seven (0; 0.5; 1.0; 10.0; 25.0; 50.0; 100.0%) and nine (0.1; 0.25; 0.5; 1.0; 2.0; 10.0; 25.0; 50.0; 100.0%) concentrations of citonella oil were used on in vitro trials with engorged female ticks. The efficacy control ticks was 0; 44.2; 92.1; 85.6; 87.8; 87.0; 88.9 and 0; 0.7; 2.8; 51.6; 79.3; 81.0; 87.1; 86.7 89.5 %, respectively. These sugest that the citronella oil can be practical used for controlling of catle ticks. ABSTRACT This research was aimed at evaluating in vitro and in vivo effects of citronella (Cymbopogon nardus (L.) Rendle) oil on catle ticks. The volatile oil was obtained from de fresh leaves of citronella grass by steam destilation and the yelds was

Bezerros foram imunizados com duas vacinas contra o herpesvírus bovino tipo 1 (BHV-1; vacina A, n=28; B, n=28) ou com uma vacina contendo antígenos do BHV-1 e BHV-5 (n=32) e a atividade neutralizante sérica antiBHV-1 e BHV-5 foi testada após três doses vacinais. Todos os animais (n=88) produziram anticorpos com atividade neutralizante antiBHV-1 (títulos médios geométricos [GMT] de 13,1; 14,8 e 34,3 para as vacinas A, B e C, respectivamente) e 82 animais (93,2%) desenvolveram atividade neutralizante antiBHV-5 (GMTs: 10,6; 11,5 e 29,8, respectivamente). Nos três grupos vacinais, os títulos médios antiBHV-1 não diferiram dos títulos antiBHV-5. No entanto, comparando-se os títulos médios entre as vacinas, os títulos neutralizantes para o BHV-1 e BHV-5 foram superiores nos animais do grupo C (p<0,01 ). Esse grupo também apresentou a maior proporção de reagentes ao BHV-5 (96,9%; contra 85,7% da vacina A e 92,9% da vacina B). Esses resultados demonstram que a vacina C induziu títulos neutralizantes superiores contra os dois vírus e que anticorpos induzidos por antígenos do BHV-1 (vacinas A e B) possuem atividade neutralizante relevante também contra o BHV-5.

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A serological survey on Ehrlichia canis was conducted among dogs in the central area of the state of Rio Grande do Sul, where the tick Rhipicephalus sanguineus is a common parasite of dogs. Out of a total of 316 dogs attended at the veterinary teaching hospital in the municipality of Santa Maria, only 14 (4.43%) reacted positively to E. canis antigens in the indirect immunofluorescence assay, with the following endpoint titers: 80 (three dogs), 160 (five), 320 (four), 640 (one) and 1280 (one). Like in previous studies in other regions of the state of Rio Grande do Sul, only a very small portion of the dogs in Santa Maria presented antibodies reactive to E. canis, even though canine infestations due to R. sanguineus are very common in this study region. These results contrast with other regions of Brazil, where E. canis is endemic among canine populations, with seropositivity values generally higher than 30%. Genetic differences among the R. sanguineus populations in South America might be implicated in these contrasting results.

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