Anti-Toxoplasma gondii and Anti-Neospora caninum Antibodies in Urban Traction Equids in Northeast Brazil: Seroprevalence and Risk Factors.

The aim of this study was to describe the prevalence of anti-T. gondii and anti-N. caninum antibodies in equids that carry out traction work in Northeastern Brazil, and to establish the potential risk factors associated with seropositivity for these agents. Blood samples were collected from 322 traction equids (horses, donkeys and mules) in urban areas of 16 municipalities in the State of Paraíba, Brazil. The samples were sent for serological diagnosis using the Immunofluorescence Antibody Test (IFAT). Epidemiological questionnaires were given to the owners to assess the possible risk factors associated with infections. It was observed that 13.7% (44/322, CI: 10.9-16.5) of the equids tested positive for anti-T. gondii antibodies and 5% (16/322, CI: 2.6-7.4) tested positive for anti-N. caninum antibodies. Conducting traction work for over four years was considered a risk factor associated with T. gondii infection (odds ratio: 6.050; CI: 4.38-8.54, p = 0.025). There were no risk factors associated with N. caninum infection. It was concluded that traction equids have a significant prevalence of anti-T. gondii and anti-N. caninum antibodies in urban areas in the State of Paraíba, with an identified risk factor for seropositivity for anti-T. gondii as conducting traction work for more than four years.

Epidemiological survey of gastrointestinal infections by gastrointestinal nematodes and coccidia in cattle in the semiarid region of Northeastern Brazil / Levantamento epidemiológico das infecções gastrintestinais por nematóides astrintestinais e coccídios em bovinos no Semiárido do Nordeste do Brasil

The aim of the present study was to carry out an epidemiological survey on gastrointestinal infections by nematodes and coccidia in cattle herds in the semiarid region of Paraíba, northeastern Brazil. A total of 832 cattle were sampled, of both sexes and different ages, on 21 farms in 21 municipalities in the state of Paraíba, Brazil. Fecal samples were collected individually to perform eggs per gram (EPG) and oocysts per gram (OoPG) counts in feces, and to perform fecal cultures. To assess factors associated with nematode and coccidia infections, epidemiological survey forms were applied to the farmers. The total frequency of infections by nematodes was 59.6% (496/832) and it was 36.9% (307/832) for coccidia. The levels of infection by nematodes and coccidia were most frequently low (EPG < 300; OoPG < 1,000), in 72.4% (359/496) and 75.2% (231/307), respectively. The most frequent nematode genera was Haemonchus spp. (78.8%). The risk factors for nematode infections in cattle were beef production trait (odds ratio = 2.99) and extensive rearing system (odds ratio = 3.8); the factors for coccidia were age ≤ 12 months (odds ratio = 2.9) and body score between 1 and 2 (odds ratio = 5.2). These results prove that there are high frequencies of gastrointestinal infections by nematodes and coccidia in cattle herds in the semiarid region of Paraíba, with predominantly low levels of infection. However, given the importance of subclinical infections, adjustments to sanitary management measures can contribute to reduction of parasite indices and better performance among the animals, thus generating greater profitability for farmers.

O objetivo do presente estudo foi realizar uma análise epidemiológica sobre as infecções gastrintestinais por nematóides e coccídios em rebanhos bovinos na região semiárida da Paraíba, Nordeste do Brasil. Um total de 832 bovinos foram utilizados, de ambos os sexos e diferentes idades, oriundos de 21 fazendas em 21 municípios do estado da Paraíba, Brasil. Amostras fecais individuais foram coletadas para a realização de contagens de ovos por grama (OPG) e oocistos por grama (OoPG) de fezes e para realizar coproculturas. Para obter os fatores associados às infecções por nematódeos e coccídios, questionários epidemiológicos foram aplicados aos produtores. A frequência total de infecções por nematóides foi 59,6% (496/832) e 36,9% (307/832) para coccídios. O nível de infecção para nematóides e coccídios mais frequente foi o baixo (OPG < 300; OoPG < 1.000), em 72,4% (359/496) e 75,2% (231/307), respectivamente. O gênero de namatóide mais frequente foi Haemonchus spp. (78,8%). Os fatores de risco para infecções por nematóides em bovinos foram aptidão para corte (odds ratio = 2.99) e sistema de criação extensivo (odds ratio = 3,8); os fatores para infecções por coccídios foram idade ≤ 12 meses (odds ratio = 2,9) e escore corporal entre 1 e 2 (odds ratio = 5,2). Estes resultados demonstraram que são elevadas as frequências de infecções gastrintestinais por nematóides e coccídios em rebanhos bovinos no Semiárido da Paraíba, com predominância de infecções em nível baixo. Entretanto, devido a importância das infecções subclínicas, ajustes em medidas de manejo sanitário podem contribuir para a redução dos índices de infecções por parasitos e melhorar a performance entre os animais, gerando maiores benefícios econômicos aos produtores.

Cross-resistance between macrocyclic lactones in populations of Rhipicephalus microplus in Brazil's semiarid region.

Rhipicephalus microplus, also known as the cattle tick, is the parasite with the greatest impact on cattle in Brazil. The most common method for controlling this tick is the application of synthetic chemical acaricides, especially ivermectin, which belongs to the group of macrocyclic lactones (MLs). However, because ivermectin is widely used, there is concern about the development of cross-resistance within this chemical class. Thus, engorged females were collected from farms with a history of resistance to ivermectin, which was the only one among the MLs that was used as an endectocide drug. Using larval immersion tests (LIT), bioassays were performed with ivermectin, moxidectin and eprinomectin on populations of R. microplus from the semiarid region of the states of Paraíba and Ceará, Brazil. Epidemiological questionnaires were applied to collect information about tick control management. All the evaluated populations showed cross-resistance between ivermectin and moxidectin, but only one population showed cross-resistance between ivermectin and eprinomectin. Weekly or monthly administration of injectable 1% ivermectin on farms was reported. It was concluded that the frequent use of ivermectin may lead to the development of cross-resistance to moxidectin. For eprinomectin, despite the structural similarity, cross-resistance was not observed in three tick populations.

Control of sheep gastrointestinal nematodes on pasture in the tropical semiarid region of Brazil, using Bioverm® (Duddingtonia flagrans).

We aimed to evaluate a Brazilian commercial formulation of the fungus Duddingtonia flagrans (Bioverm®) for controlling gastrointestinal nematodes in sheep kept on native pasture in the Caatinga biome, in the semiarid region of Brazil. Twenty ewes, aged between 12 and 18 months, were divided into two groups. In the treated group, each animal received 1 g of the Bioverm® product for each 10 kg of live weight, daily, together with commercial feed, for 6 months. In the control group, the animals received feed without Bioverm®. Each group remained throughout the experiment in a 1.2-ha paddock. Monthly counts of eggs per gram (EPG) of feces, fecal cultures, packed cell volume (PCV), weight measurements, and collection of leaf mass from the pasture were performed. There was greater reduction in EPG, greater weight gain, and less infestation by infective larvae in the paddock of the Bioverm® group, compared with the control group (p < 0.05). There was no significant difference (p ≥ 0.05) in the mean PCV percentage between the Bioverm® and control groups. In coprocultures, Haemonchus sp. was the most prevalent helminth. Bioverm® (D. flagrans) was efficient for biological control of sheep gastrointestinal nematodes in the semiarid region of Brazil.

Seroprevalence and isolation of Toxoplasma gondii in sheep intended for human consumption in Paraíba, northeastern Brazil.

Toxoplasma gondii is a zoonotic parasite capable of infecting almost all warm-blooded animals. Currently, studies assessing the viability of cysts present in sheep meat are still scarce, especially in the northeastern region of Brazil. Therefore, the aim of this study was to evaluate the seroprevalence of anti-Toxoplasma gondii antibodies, isolate the parasite from tissue samples, and determine factors associated with infection of sheep intended for human consumption in the state of Paraíba, northeastern Brazil. Serum samples from 205 sheep slaughtered in Paraíba were tested using the indirect fluorescence antibody test (IFAT ≥ 64) for the presence of anti-T. gondii antibodies. Among the animals sampled, 30.7% (63/205) were seropositive, with antibody titers ranging from 1:64 to 1:16384. Sixty-one bioassays were performed in mice, and an isolation rate of 47.5% (29/61) was obtained. The infection was lethal to at least one infected mouse in 24.1% (7/29) of the bioassays. The mean length of survival of infected mice was 36.4 days. Females (OR = 3.183; CI = [1.452-6.976]), extensive breeding system (OR = 2.612; CI = [1.120-6.094]), and purebred animals (OR = 2.157; CI = [1.009-4.612]) were considered to be factors associated with infection. These results revealed that the prevalence of anti-T. gondii antibodies and the percentage of viable cysts recovered from sheep destined for human consumption in Paraíba, northeastern Brazil, were high.