Highlights First risk factor-study on N. caninum infection in Antioquia department, Colombia. Horizontal transmission is an important mode of infection in the studied region. Abortion, age, origin and poor hygienic practices associated with manual milking are risk factors for N. caninum infection.

Neospora caninum is a tissue-cyst forming parasite that has been recognized worldwide as a cause of abortion in cattle. Despite the ubiquitous distribution of this parasite and its broad range of hosts, the number of N. caninum isolates obtained to date is limited. In addition, the majority of isolates have been obtained from clinically affected hosts, therefore potentially biasing this population towards more virulent isolates. This report describes the isolation and biological characterisation of a new N. caninum isolate, Nc-Goiás 1, obtained from an asymptomatic, naturally infected calf from Brazil. This new isolate was identified as a member of the N. caninum species by polymerase chain reaction (PCR) using specific primers based on the N. caninum internal transcribed spacer 1 (ITS-1) sequence, and was genetically identified at multiple loci using microsatellite analysis. Finally, a pathogenicity study was conducted in a BALB/c mice model. All Nc-Goiás 1-infected mice survived without exhibiting any clinical signs. Further pathogenic characterisation of this isolate suggested that Nc-Goiás 1 is less virulent than other N. caninum isolates (Nc-Liv and Nc-1) studied in this mouse model. This is the first report of the isolation and biological characterisation of N. caninum from an infected but clinically healthy calf in South America.

ResumoEste estudo comparou a soroprevalência de N. caninum e T. gondii em bovinos Curraleiros ao de outras raças bovinas (Nelore, Girolando, Guzerá e Caracu). Foram utilizadas 119 fêmeas bovinas adultas provenientes de quatro propriedades localizadas nos estados de Goiás e Tocantins e na divisa entre Goiás, Minas Gerais e Bahia. Animais soropositivos para N. caninum foram encontrados em todas as propriedades e o número de Curraleiros reagentes foi significativamente maior em relação aos bovinos Guzerá e Nelore. Também foram identificados anticorpos anti-T. gondii nos animais em todas as propriedades. A prevalência de soropositivos para T. gondii foi semelhante entre Curraleiros e bovinos das raças Nelore, Girolando e Guzerá; entretanto, foi significativamente maior em relação à raça Caracu. Palavras-chave: bovino; neosporose; Pé-duro; raças locais; toxoplasmose. AbstractThis study compared the health status of Curraleiro cattle and other breeds (Nellore, Girolando, Guzera, and Caracu) for toxoplasmosis and neosporosis screening against anti-Neospora caninum and anti-Toxoplasma gondii antibodies, respectively. We used 119 female bovines of Curraleiro, Guzera, Nellore, Caracu, and Girolando breeds from four farms in Goias and Tocantins states and in the border of Goias, Minas Gerais, and Bahia states. All the farms had seropositive bovines for N. caninum. The number of seropositive Curraleiro cattle was significantly higher than the number of Guzera and Nellore cattle. Also, antibodies against toxoplasmosis were found in animals from all properties. There was no significant difference between the number of seropositive Curraleiro cattle

No abstract

The Neospora caninum microsatellite markers were applied to clinical samples. Genotyping technology involving fluorescently labelled DNA fragment analysis was used in combination with DNA sequencing for markers with complex repetitive sequences. Nineteen DNA samples from 15 brains and four hearts of naturally infected non-aborted zebuine foetuses from abattoirs in Goiás, Brazil. N. caninum had been detected in these foetuses by nested-PCR of the internal transcribed spacer-1 rRNA region, and the samples were analysed using these microsatellites. Seven complete or nearly complete allele profiles were obtained from six foetuses. Three distinct profiles of N. caninum were identified in a unique microregion (Meia Ponte) of Goiás. Two alleles for the same marker were detected in a unique foetus that was probably infected with two different strains. A new allele for one of the microsatellites is described. The multilocus analysis performed here revealed a preliminary means of discriminating between individual strains according to their geographical origins. These are the first results that have been obtained regarding the molecular characterisation of strains of N. caninum from infected zebuine foetuses in South America and reveal for the first time that there are genotypic differences in the strains that are responsible for foetal transmission in zebuine foetuses.

This study was developed to evaluate the repellent activity of N,N-diethyl-3-methylbenzamide (DEET) against Amblyomma cajennense nymphs. Two repellent bioassays were compared and the effective concentration and repellent time were calculated. The fingertip test was accomplished to evaluate in vivo four concentrations of the compound (0.200; 0.100; 0.050 and 0.025 mg.cm ) and the filter-paper bioassay to evaluate in vitro the two highest concentrations. The compound provided repellence higher than 90% in all concentrations and at least 95% repellency in the highest concentration over 5 hours. The effective concentration against 50% of tested nymphs (EC50) was 0.006 mg.cm -2 and the EC99 was 0.036 mg.cm -2 . Those concentrations were lower than the ones obtained against other tick species, denoting the effectiveness of DEET against A. cajennense. The repellency time against 50% of the ticks (RT50) was 4.8 hours and the RT90 was 2.7 hours. Both bioassays were adequate to evaluate A. cajennense repellency and provided similar results; however the in vivo test is more appropriate to estimate the effective concentration and repellency time.Keywords: DEET, Amblyomma cajennense, repellency time, fingertip bioassay. ResumoEste estudo foi conduzido com o objetivo de avaliar a atividade repelente do N,N-diethyl-3-methylbenzamide (DEET) sobre ninfas de Amblyomma cajennense. Dois bioensaios para a avaliação de repelência foram comparados e cálculos da concentração eficaz e do tempo de repelência foram realizados. Foram empregados o bioensaio da ponta do dedo, para avaliação in vivo de quatro concentações do químico (0,200; 0,100; 0,050 e 0,025 mg.cm -2 ) e o bioensaio do papel filtro, para a avaliação in vitro das duas concentrações mais altas. O composto conferiu mais de 90% de repelência em todas as concentrações utilizadas e 95% de repelência por mais de cinco horas na maior concentração. A concentração do composto efetiva contra 50% das ninfas testadas (CE50) foi de 0,006 mg.cm -2 e a CE99 foi de 0,036 mg.cm -2 . Estas concentrações são mais baixas do que as observadas em outras espécies de carrapatos, denotando a efetividade do princípio contra A. cajennense. O tempo de repelência de 50% dos carrapatos (TR50) foi de 4,8 horas e o TR90 de 2,7 horas. Os dois bioensaios avaliados permitiram a observação de percentuais de repelência igualmente altos e se mostraram adequados para tal avaliação, sendo que o teste in vivo é mais indicado para cálculo da concentração eficaz e da duração da repelência.Palavras-chave: DEET, Amblyomma cajennense, tempo de repelência, bioensaio ponta do dedo.

No abstract

No abstract