Prevalence of endoparasites by microscopic analysis in free-range chickens in a Brazilian semiarid region.

The aim of this study was to evaluate the prevalence and diversity of endoparasitic fauna and the risk factors associated with parasite infections in free-range chickens in the state of Paraíba, northeastern Brazil. Ten municipalities were visited and, in each of them, ten farms, to collect animal feces and apply epidemiological questionnaires. Feces from 417 poultry were used to perform EPG (eggs per gram) and OoPG (oocysts per gram) tests. Prevalences of 40.52% (169/417) and 39.08% (163/417) were observed for nematodes and coccidia, respectively. In 17% (71/417), mixed infections by nematodes and coccidia were observed. Nematodes of Heterakoidea superfamily were present in 100% of the positive samples (169/169), followed by Trichuris spp. (57.3%; 97/169). All the protozoan oocysts observed belonged to the genus Eimeria (100%; 163/163). The variable of presence of drooping wings was considered to be a factor associated with infection by coccidia (odds ratio = 5.412; confidence interval: 1.179-24.848; p = 0.030). It was concluded that there is high prevalence of nematodes and coccidia in free-range chickens in the state of Paraíba, Brazil. Better sanitary management measures, with greater hygiene of facilities, together with chemical control of parasites, can improve productivity by reducing the rate of gastrointestinal parasites.

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.

The diversity of Eimeria spp. in cattle in the Brazilian Semiarid region.

The aim of the present study was to find out the diversity of Eimeria species in cattle herds in the semiarid region of Brazil. Forty cattle fecal samples were collected from 20 farms in the Paraíba State, Northeast Brazil, and examined by centrifugation-floatation technique in sucrose solution. From each positive animal, 20 oocysts were photographed and measured. Infection by Eimeria spp. was detected in 17.12% (137/800) of the samples analyzed. All the farms had at least one animal that was positive for Eimeria spp. (100%; 20/20). In total, 2740 coccidia were photographed and measured. The species detected were: Eimeria bovis (35.1%); Eimeria canadensis (17.48%); Eimeria auburnensis (14.7%); Eimeria ellipsoidalis (9.7%); Eimeria zuernii (7.22%); Eimeria brasiliensis (4.56%); Eimeria bukidnonensis (3.97%); Eimeria illinoisensis (2.91%); Eimeria wyomingensis (1.42%); Eimeria alabamensis (1.27%); Eimeria cylindrica (0.76%); Eimeria pellita (0.54%); Eimeria ildefonsoi (0.21%); and Eimeria subspherica (0.07%). It was concluded that cattle in the semiarid region of Brazil were parasitized by 14 species of Eimeria. It is thinked that the sanitary management employed, as well as the system used for raising these animals, is the crucial point that leads to high rates of infection in this region.

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.

Resistance of bovine gastrointestinal nematodes to four classes of anthelmintics in the semiarid region of Paraíba state, Brazil.

The effectiveness of four anthelmintic classes on cattle gastrointestinal nematodes in the semi-arid region of Paraiba State, Brazil, was evaluated. Twenty farms were used, testing 40 animals in each one, totaling 800 animals. Cattle were divided into four groups composed with ten animals: I, treated with albendazole sulfoxide 15%; II, treated with ivermectin 1%; III, treated with closantel 25%; IV, treated with levamisole hydrochloride 7.5%. All treatments were administered subcutaneously. For the Fecal Egg Count Reduction Test (FECRT), individual fecal samples were collected on days 0 and 14, and sent for analysis of egg count per gram of feces (EPG) and larval cultures. It was observed that multiresistance was present in 95% (19/20) of the farms. Resistance to ivermectin and albendazole was observed in 95% (19/20), to closantel in 75% (15/20) and to levamisole in 20% (4/20). The most used management system was semi-intensive (75%; 15/20) and the ivermectin was the most reported drug for controlling helminths (65%; 13/20). Haemonchus spp. was the most prevalent helminth genus. It was concluded that the anthelmintic resistance of bovine gastrointestinal nematodes is high in the semi-arid of Paraíba State, Brazil, with multiresistance observed mainly to ivermectin, albendazole and closantel.

Resistance of bovine gastrointestinal nematodes to four classes of anthelmintics in the semiarid region of Paraíba state, Brazil / Resistência de nematódeos gastrintestinais de bovinos à quatro classes de anti-helmínticos no semiárido do Estado da Paraíba, Brasil

Abstract The effectiveness of four anthelmintic classes on cattle gastrointestinal nematodes in the semi-arid region of Paraiba State, Brazil, was evaluated. Twenty farms were used, testing 40 animals in each one, totaling 800 animals. Cattle were divided into four groups composed with ten animals: I, treated with albendazole sulfoxide 15%; II, treated with ivermectin 1%; III, treated with closantel 25%; IV, treated with levamisole hydrochloride 7.5%. All treatments were administered subcutaneously. For the Fecal Egg Count Reduction Test (FECRT), individual fecal samples were collected on days 0 and 14, and sent for analysis of egg count per gram of feces (EPG) and larval cultures. It was observed that multiresistance was present in 95% (19/20) of the farms. Resistance to ivermectin and albendazole was observed in 95% (19/20), to closantel in 75% (15/20) and to levamisole in 20% (4/20). The most used management system was semi-intensive (75%; 15/20) and the ivermectin was the most reported drug for controlling helminths (65%; 13/20). Haemonchus spp. was the most prevalent helminth genus. It was concluded that the anthelmintic resistance of bovine gastrointestinal nematodes is high in the semi-arid of Paraíba State, Brazil, with multiresistance observed mainly to ivermectin, albendazole and closantel.

Resumo Avaliou-se a eficácia de quatro classes de anti-helmínticos sobre nematódeos gastrintestinais de bovinos na região semiárida da Paraíba, Brasil. Foram utilizadas 20 fazendas, sendo testados 40 animais em cada uma, totalizando 800 animais. Os bovinos foram distribuídos em quatro grupos compostos por dez animais: I, tratado com sulfóxido de albendazol 15%; II, tratado com ivermectina 1%; III, tratado com closantel 25%; IV, tratado com cloridrato de levamisole 7,5%. Para o Teste de Redução da Contagem de Ovos Fecais (TRCOF), amostras fecais individuais foram coletadas nos dias 0 e 14 e enviadas para análises de contagem de ovos por grama de fezes (OPG) e coproculturas. Observou-se que a multirressistência estava presente em 95% (19/20) das fazendas. Foi observada resistência à ivermectina e ao albendazol, em 95% das fazendas (19/20); ao closantel, em 75% (15/20) e, ao levamisole, em 20% (4/20). O sistema de manejo mais utilizado foi o semi-intensivo (75%; 15/20) e a ivermectina foi o fármaco mais relatado para controle de verminose (65%; 13/20). O gênero de helminto mais prevalente foi Haemonchus spp. (76,7%). Conclui-se que é alta a resistência anti-helmíntica por nematódeos gastrintestinais de bovinos no Semiárido da Paraíba, Brasil, com multirressistência observada principalmente à ivermectina, ao albendazol e ao closantel.