Shedding of Neospora caninum oocysts by dogs fed different tissues from naturally infected cattle.

Neospora caninum is one of the most important causes of abortion in dairy cattle worldwide. The distribution of N. caninum in tissues of adult cattle is unknown and the parasite has not been demonstrated histologically in tissues of cows. In the present study the distribution of N. caninum in different tissues of adult cattle was evaluated by bioassays in dogs. Seventeen dogs (2-3 month-old) were fed different tissues of 4 naturally exposed adult cattle (indirect fluorescent antibody test N. caninum titer ≥ 400): 5 were fed with masseter; 5 with heart, 3 with liver, 4 with brain, and 3 pups were used as non-infected control. Two dogs fed masseter, 2 fed heart, 1 fed liver, and 3 fed brain shed oocysts, and all dogs presented no seroconvertion to N. caninum during the observation period of 4 weeks. The oocysts were confirmed as N. caninum based on the detection of N. caninum-specific DNA by PCR and sequencing. The results indicate that dogs can be infected by N. caninum with different tissues of infected cattle.

Isolation and molecular detection of Neospora caninum from naturally infected sheep from Brazil.

Neospora caninum was isolated from a naturally infected sheep from Brazil by bioassay in dogs. Approximately 70g of brain from each of two 4-month-old sheep with indirect fluorescent antibodies (>or=1:50) to N. caninum was offered to a different IFAT negative dog (Sheep n. 302, IFAT 1:400-Dog 1 and Sheep n. 342, IFAT 1:50-Dog 2). Parasite DNA was detected in both sheep brains using a PCR targeting the Nc-5 gene of N. caninum. Shedding of Neospora-like oocysts was noticed only in Dog 1, from 10 days post-inoculation (PI) to 25 days PI (a total of approximately 27,600 oocysts). Seventy days after infection, Dog 1 was euthanized and brain/cerebellum and medulla were collected and submitted to molecular methods, as were the oocysts, to confirm the identity of the isolate. Serum samples collected weekly from both dogs from the infection to the end of the experimental period had no antibodies anti-N. caninum by IFAT (<1:50). Oocysts, brain/cerebellum and medulla specimens of Dog 1 proved positive by a PCR assay targeting the Nc-5 gene of N. caninum. In addition, the oocysts have the DNA amplified by a PCR based on primers directed to the common toxoplasmatiid ITS1 sequence. The PCR products of ITS1 were sequenced, confirming again the isolate as N. caninum. Oocysts were also orally inoculated in two Swiss white mice two Mongolian gerbils (Meriones ungulatus) and two large vesper mice (Calomys callosus) (10(3)oocysts/animal). The rodents were sacrificed 2 months PI, and fresh preparations of brains showed Neospora thick-walled cysts in gerbil brains, but molecular detection using the Nc-5 PCR assay revealed DNA parasite in gerbil and also C. callosus brains. This is the first report of isolation and sequencing of N. caninum from a Brazilian sheep and the first report of molecular detection of N. caninum from C. callosus.

Biological and genetic characterisation of Toxoplasma gondii isolates from chickens (Gallus domesticus) from São Paulo, Brazil: unexpected findings.

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 (> or =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.

Seroprevalence of Neospora caninum in female water buffaloes (Bubalus bubalis) from the southeastern region of Brazil.

Antibodies to Neospora caninum were assayed in sera of 222 female water buffaloes from Ribeira Valley of São Paulo State, Brazil, using an indirect fluorescent antibody test (IFAT) and Neospora agglutination test (NAT). IFAT antibodies were found in 64% of buffaloes with titers of 1:25 (42 buffaloes), 1:50 (53 buffaloes), 1:100 (31 buffaloes), 1:200 (10 buffaloes), 1:400 (3 buffaloes), or > or =1:800 (3 buffaloes). NAT antibodies were found in 53% of buffaloes; in titers of 1:40 in 52 buffaloes, 1:80 in 27 buffaloes, 1:160 in 21 buffaloes, and > or =1:320 in 17 buffaloes. Results indicate a high prevalence of N. caninum exposure in water buffaloes in Brazil and warrant an investigation of the role of N. caninum as an abortifacient in water buffaloes.

Antibody levels in goats fed Toxoplasma gondii oocysts.

Outbred goats were fed 10(5) Toxoplasma gondii oocysts and were monitored twice weekly for 8 wk for rectal temperature, clinical signs, parasitemia, and antibody levels by indirect fluorescence antibody test (IFAT), latex agglutination test (LAT), and indirect enzyme-linked immunosorbent assay (ELISA). After 8 wk, all goats were killed, and samples of heart, skeletal muscle, brain, lymph nodes, kidneys, and liver were bioassayed in mice. Anorexia, fever, and lethargy were observed from day 3 to day 7 postinfection (PI). Parasitemia was detected by bioassay in 50% of infected goats from day 7 to day 14 PI. Viable T. gondii organisms were isolated from all infected goats. Antibodies to T. gondii were detected in some animals on day 10 PI by IFAT and LAT and on day 14 PI by ELISA. The infected goats were seropositive on day 17 PI.

Eficácia e persistência da associaçäo de cipermetrina 4,5 por cento + DDVP 50 por cento (Ectorfarma) no controle do Boophilus microplus e de larvas de Dermatobia hominis em bovinos leiteiros, mestiços, naturalmente infestados / Efficacy and persistance of cypermethrin 4,5 per cent + DDPV 50 per cent (Ectofarma) in the control of Boophilus microplus and larvae of Dermatobia hominis on naturally infested crossbred dairy cattle

Testou-se a sensibilidade da cepa de B. microplus do campus de Pirassununga da USP ao Ectofarma, na diluiçäo 1:400 através do biocarrapaticidograma. A ovipostura no grupo tratado (A) foi reduzida em 95,34 por cento, em relaçäo ao grupo controle (B) e a eclosäo de larvas provenientes dos ovos do grupo B foi de 100 por cento, enquanto no grupo A näo ocorreu eclosäo. Diante desse resultado, efetuou-se o teste a campo, utilizando dois grupos de nove bovinos mestiços. No dia 0 os números médios de B. microplus > 5 mm e de bernes nos animais dos dois grupos eram estatisticamente iguais. Os bovinos do grupo A foram aspergidos com o produto na mesma diluiçäo utilizada no teste in vitro. Os carrapatos foram contados nos dias 1, 2, 3, 7, 14, 21, 28, 35, e 42 e os bernes no 3§ dia pós-tratamento (dpt), e depois, semanalmente, até a 6§ semana. Houve reduçäo drástica no número médio de carrapatos do grupo A do primeiro ao 21§ dpt, aumentando a partir do 28§ dpt. A reduçäo do número médio de larvas de D. hominis chegou a 65 por cento no 3§ dpt, nos animais do grupo tratado, e embora a eficácia do produto tenha sido baixa, o número médio de bernes no grupo A foi sempre menor do que no grupo B, após o tratamento

Eficácia anti-helmíntica de três doses de uma associaçäo de pamoato de pyrantel, pamoato de oxantel e praziquantel em gatos naturalmente infectados / Anthelmintic efficacy of three doses of an association of pyrantel pamoate plus, oxantel pamoate and praziquantel in naturally infected cats

O presente trabalho teve por objetivo avaliar a atividade anti-helmíntica de três diferentes doses de uma associaçäo de pamoato de pyrantel, pamoato de oxantel e praziquantel em dose única e via oral, em gatos naturalmente parasitados. Os animais foram obtidos no Centro de Controle de Zoonoses do Município de Diadema (SP) e divididos em quatro grupos de oito animais cada, baseados nos resultados de exames coproparasitológicos. Os gatos do Grupo 1 näo receberam tratamento, os do Grupo 2 foram tratados com 5 mg de pamoato de pyrantel, 5 mg de pamoato de oxantel e 2,5 mg de praziquantel/kg de peso vivo (pv). Os gatos de Grupo 3 receberam 10 mg de pamoato de pyrantel, 10 mg de pamoato de oxantel e 5 mg de praziquantel/kg pv e aos animais do Grupo 4 foram ministrados 20 mg de pamoato de pyrantel, 20 mg de pamoato de oxantel e 10 mg de praziquantel/kg pv. Calculou-se a porcentagem de reduçäo do número de ovos presentes nas fezes e a porcentagem de eficácia. As médias dos números de ovos tiveram um decréscimo significativo já no segundo dia pós-tratamento, independente da dose de medicamento utilizada. Houve decréscimo, näo significativo, dos números de formas imaturas de Toxocara cati e de Ancylostoma spp. nos grupos tratados e significativo em relaçäo às formas adultas. A porcentagem de eficácia contra Toxocara cati foi de 93,0 por cento; 97,6 por cento e 100,0 por cento para os grupos 2, 3 e 4, respectivamente. Em relaçäo ao Ancylostoma spp. a eficácia foi de 96,5 por cento, 99,0 por cento e 100,0 por cento. O produto mostrou-se eficaz contra Dipylidium caninum, mas näo atuou sobre Physaloptera spp. e Strongyloides stercoralis, no esquema de administraçäo utilizado