Seroprevalence of Toxoplasma gondii and Neospora caninum in sheep intended for human consumption in the Rondônia state, Western Brazilian Amazon.

The aim of this study was to carry out a seroepidemiological study of anti-T. gondii and anti-N. caninum antibodies in serum samples from sheep intended for human consumption in the Rondônia state, in the Western Brazilian Amazon, and identify possible risk factors associated with seropositivity. The analysis of the 616 sheep serum samples revealed animal-level seroprevalence of T. gondii in the order of 52.4 % and of N. caninum of 60.6 %. Prevalence of co-infections was 33.4 %. The herd-level seroprevalence was 100 % for both the parasites. Applying of multivariate logistic regression analysis, test of the association between seroprevalence of T. gondii infection and the potential predictors showed that feed, fetal malformation, abortion, neurological problems (lambs), presence of rodents were the significant (P < 0.05) predictors. The variables presence of rodents, cats, wild animals and main activity showed statistical association (P < 0.05) with the seroprevalence of N. caninum. Due to the high prevalence of T. gondii and N. caninum found in this study, the absence of specific slaughterhouses for sheep and raw or undercooked sheep meat for human consumption we concluded that sheep can represent an important source of infection for humans.

Risk factor analysis associated with Neospora caninum in dairy cattle in Western Brazilian Amazon.

Neospora caninum is considered to be one of the main causes of abortion among cattle. The present survey was conducted in the municipality of Rolim de Moura, Rondônia State, Brazil. A questionnaire that investigates the epidemiological aspects of neosporosis was used in the analysis of risk factors associated with the animal-level and herd-level prevalence in dairy cattle. A total of 416 bovine blood samples were collected from 30 farms, and N. caninum antibody levels were measured by Indirect Fluorescent Antibody Test (IFAT). Analysis of dairy cattle serum samples revealed the presence of anti-N. caninum antibodies to be 47.36% (n = 197). Risk factors associated with N. caninum infection were the management system and access locations of dogs. The results of the present survey indicated that infection of dairy cattle with N. caninum is widespread in the studied region of Western Amazon, which has implications for prevention and control of neosporosis in this region. Therefore, integrated control strategies and measures are recommended to prevent and control N. caninum infection in dairy cattle. In addition, direct contact between dairy cattle, dogs and wild animals, which can influence the epidemiology of neosporosis, should be investigated further.

Investigation of fecal egg counts versus worm burden and helminth fauna in cattle treated or not with macrocyclic lactones in a tropical region.

Gastrointestinal nematodes negatively impact the health and productivity of livestock. Macrocyclic lactones (MLs) are the most common class of chemicals used in helminth control programs, however, their intense use is accelerating the development of parasite resistance. For cattle, little is known regarding the relationship between fecal egg counts (FECs) and the helminth population inside the animal's gastrointestinal tract and so this study evaluated the correlation between FEC and worm burden in cattle treated or not with MLs (ivermectin 200 µg/kg, ivermectin 630 µg/kg, abamectin 200 µg/kg, doramectin 700 µg/kg and moxidectin 200 µg/kg). Animals were necropsied to determine if there were any modifications to the proportions of worm species due to chemical treatment. FECs of ML-treated and untreated animals showed significant (p ≤ 0.05 and R2 ≥0.70) positive linear correlations and substantial or perfect strength-of-agreement (LCCC ≥ 0.61) with total worms present, all of which were Haemonchus placei and Cooperia punctata. However, this correlation and strength-of-agreement did not occur when the efficacy of MLs was ≥80 % against these helminths. Among the active MLs tested, moxidectin had the weakest relationship between FEC and worm burden, except for H. placei. Analysis of the helminthological fauna found an increase of H. placei (35.6 % = 95 % CI 35.4-35.6) and a consequent decrease of C. punctata (52.5 % = 95 % CI 52.3-52.6) in untreated animals, when compared to studies carried out over 20-40 years ago, but this proportion was reversed for ML-treated animals (C. punctata 64.5 % = 95 % CI 64.4-64.8; H. placei 30.8 % = 95 % CI 30.6-30.8). It is possible that MLs mitigate this effect in the field and that C. punctata remained prevalent in cattle in different regions of Brazil.

Toxoplasma gondii: Evidence for the transmission by semen in dogs.

Ten male dogs were distributed into three experimental groups for infection with Toxoplasma gondii: GI - three dogs inoculated with 2.0x10(5) P strais oocysts, GII - three dogs infected with 1.0x10(6) RH strain tachyzoites, and GIII - four controls dogs. Several clinical parameters were evaluated. IFAT was performed to detect anti-T. gondii antibodies. Presence of the parasite in semen was evaluated by PCR and bioassay techniques. Tissue parasitism was examined using bioassays and immunohistochemistry in testicle and epididymis fragments collected after orchiectomy. In semen samples collected from these two groups, the presence of T. gondii was verified by bioassays and PCR. T. gondii was detected by immunohistochemistry in tissues (testicle and epididymis fragments) of all six experimentally infected dogs. The T. gondii-positive seminal samples were used in the artificial insemination (AI) of four female dogs free of toxoplasmic infection. Seven days after AI, all of the female dogs presented serologic conversion (IFAT). Fetal reabsorption occurred in two of the dogs, while the others sustained full-term gestation. Several T. gondii cysts were detected in the brains of four offspring. These results suggest that T. gondii can be sexually transmitted in domestic dogs.

Avermectin toxicity in bovines less than thirty days old.

The present study was designed to evaluate possible adverse effects of different dosages of avermectins (abamectin and a combination of ivermectin + abamectin) administered subcutaneously in calves less than one month of age. Clinical as well as biochemical parameters of blood and cerebrospinal fluid (CSF) were evaluated for animals subjected to various treatments. Thirty-five calves were divided into seven groups of five animals each: T01 (control), T02 (abamectin 200 µg/kg), T03 (abamectin 400 µg/kg), T04 (abamectin 600 µg/kg), T05 (ivermectin 450 µg/kg + abamectin 250 µg/kg), T06 (ivermectin 900 µg/kg + abamectin 500 µg/kg) and T07 (ivermectin 1350 µg/kg + abamectin 750 µg/kg). Cerebrospinal fluid and blood samples were collected on day zero (treatment day) and on days 1, 7 and 14 following treatment. The biochemical parameters measured in blood samples were total protein and the AST, GGT and alkaline phosphatase enzymes. In CSF samples, color, aspects, pH, density, cellularity, total proteins, glucose and the CK, ALT and LDH enzymes were evaluated. No neurological toxicity or biochemical changes in the CSF or blood that could be correlated to administration of tested products were observed in this study. Though it is well known that abamectin may lead to intoxication in bovines less than four months of age, based on data from the present study, no adverse clinical effects to the CSF or blood were observed in calves <30 days old that had received up to 600 µg/kg abamectin formulations and up to 1350 µg/kg ivermectin +750 µg/kg abamectin associations. It is possible that the level and activity of the multiple drug resistance gene (MDR1 - ABCB1) present in the calves may have influenced the results obtained in this study. Future studies should be carried out.

In vivo effect of diflubenzuron, administered via mineral salt supplementation, against Haematobia irritans and Rhipicephalus microplus parasitizing cattle.

This study involved two field trials with the aim of evaluating the efficacy of diflubenzuron, via mineral supplementation, against Haematobia irritans parasitizing cattle. Concomitantly with the main trial, a stall test was conducted to ascertain the effects of a different formulation with the same active ingredient against Rhipicephalus microplus, along with the action of diflubenzuron on the reproductive parameters of R. microplusfemales that had naturally detached from cattle. Against H. irritans, it was observed that the efficacy indexes fordiflubenzuron were low (≤ 31.3% or 44.6%) or null (0.0%) throughout the study. The anti- R. microplus efficacy of diflubenzuron, at weekly intervals, ranged from 0.0 to 13.7% over the entire experimental period. Null efficacy (0.0%) was registered for diflubenzuron in relation to the reproductive parameters of R. microplusfemales that had naturally detached from cattle. The different diflubenzuron formulations, administered via mineral salt supplementation, did not show satisfactory efficacy indexes against H. irritans and R. microplus parasitizing cattle, within the experimental design of the present study. In addition, this agent did not present any deleterious effects on the reproductive parameters of R. microplus females.

Investigation of Toxoplasma gondii in semen, testicle and epididymis tissues of primo-infected cats (Felis catus).

This study aimed to investigate the presence of Toxoplasma gondii in semen, testicle and epididymis tissues of cats experimentally infected by this coccidium. A total of 12 male felines without a definite breed that were of reproductive age and serologically negative for T. gondii were selected and distributed to the following three experimental groups: GI, inoculated with 600 tissue cysts of the P strain of T. gondii (isolate III); GII, inoculated with 2×105 tachyzoites of the RH strain (isolate I); and GIII, not inoculated (control group). Prior to inoculation (day -7 and 0) and on post inoculation days (PIDs) 7, 14, 21, 28, 42, 56, and 70, all felines were subjected to assessments of anti-T. gondii IgG by indirect immunofluorescence (IIF) and assessments of parasitemia. Collection of semen (electroejaculation) was performed on the specified dates, followed by nested PCR and bioassays in mice to detect T. gondii. On PID 70, all 12 felines were orchiectomized, and the presence of the parasite in the testicles and epididymides was evaluated by nested PCR, murine bioassay, and histopathological and immunohistochemical analyses. All felines inoculated with T. gondii (GI and GII) seroconverted to the toxoplasmic infection after PID 14; on PID 7, seroconversion of three felines (P4, RH2 and RH4) could observed, and all exhibited detectable titers by PID 64. The GII felines exhibited greater serological titers compared with GI felines. The maximum serological titer (IgG) was observed in feline RH3 (titer 1024), while in other experimental felines, a maximum titer of 256 was detected. Parasitemic peaks were diagnosed in all felines of groups I and II from PIDs 7-42. A total of five parasitemic peaks were diagnosed in GI and nine in GII. In none of the experimental time points was the presence of T. gondii diagnosed in seminal samples collected from the felines or in the testicle or epididymis tissues collected from these animals. Thus, sexual transmission in domestic cats does not appear to be a major route of T. gondii infection, possibly demonstrating the tendency of this protozoan to develop a response directed to the formation and excretion of oocysts in the feces of these definite hosts, which act as its main route of perpetuation in the environment.

First outbreak and subsequent cases of Trypanosoma vivax in the state of Goiás, Brazil.

Trypanosomiasis caused by Trypanosoma vivax has increased the reports in Brazil in the last decade. An outbreak is herein first reported in the state of Goiás, from May 2016 to January 2017. The outbreak start occurred in the city of Ipameri (Goiás) after the introduction of 18 auctioned cows from the state of Minas Gerais. Direct parasitological test (blood smears) and polymerase chain reactions targeting the catL genes diagnosed T. vivax infection. Fifty six cows from a herd of 161 were infected; 12 died during the outbreak and 44 animals persistently positive (by blood smears) even after chemical treatment were discarded. After this first case, five other cases were detected in state of Goiás. The spread of this disease can be linked to the commercialization of animals carrying T. vivax, allied to the iatrogenic transmission practice, using a single needle and syringe for all cows, during oxytocin administration before each milking.

Occurrences of Oestrus ovis parasitism in necropsied sheep in the Umuarama microregion, Paraná, Brazil.

Between January 2007 and September 2013, 71 sheep belonging to 12 farms in the Umuarama microregion, State of Paraná, were evaluated regarding presence of Oestrus ovis larvae, during necropsies. The farms from which these animals originated were visited and the owners and employees were interviewed. Occurrences of O. ovis parasitism in sheep were diagnosed for the first time on this microregion. Of the 71 animals, 12 (16.9%) were parasitized by O. ovis, with mean intensity of 2.25 larvae per infested head (1 to 8 larvae/infested head). There was a high correlation (0.81, p=0.0346) between the number of larvae and the macroscopic lesions observed in these animals' nasal cavities, such that sheep with more than 3 larvae may contain mucupurulent secretions or epistaxis. From the interviews conducted, it was found that all the farm owners were applying chemical parasite control methods (helminths and/or O. ovis), administered to all animals in the herds every 30 days (91.6% of the producers), using derivatives of macrocyclic lactones and/or benzimidazoles/imidazothiazoles. Further studies need to be conducted in this particular region, in an attempt to elucidate the prevalence of O. ovis parasitism in herds.

Effect of a spray formulation on the reproductive parameters of a susceptible population of Rhipicephalus (Boophilus) microplus.

The number of studies emphasizing the possible damage that acaricidal spray formulations can cause on engorged female ticks' reproductive parameters is small. The present study evaluated the deleterious effects of a spray formulation (dichlorvos 60% + chlorpyrifos 20%) on the reproductive parameters of a susceptible population of Rhipicephalus (B.) microplus females, using the Stall Test. The ticks were allocated randomly to treatments according to the mean numbers of females detached from each cow on days -3, -2 and -1 and the cattle pen location. The numbers of engorged female ticks that naturally detached from the cattle were counted daily from day 1 to day 30. For each group, 20 detached engorged female ticks or the available number collected daily were evaluated regarding reproductive parameters. Associations of organophosphates demonstrated elevated acaricidal efficacy, as well as deleterious effects on the reproductive parameters of R. (B.) microplus females. The engorged female weight (days 1 to 7), weight of egg masses (days 5 to 10) and larval hatching percentage (days 5 to 19) were decreased (P ≤ 0.05). It is possible that a formulation can lead to deleterious effects on R. (B.) microplus females when the tick population analyzed shows elevated sensitivity towards a particular formulation. However, further studies need to be conducted.

Endoparasites of horses from the Formiga city, located in center-west region of the state of Minas Gerais, Brazil.

With the aim of studying the endoparasite fauna of horses from the Formiga city, located in center-west region of the state of Minas Gerais, 25 animals that were naturally infected with helminths were evaluated. By means of parasitological necropsies, different endoparasites were found. The subfamily Cyathostominae presented the highest incidence, followed by Trichostrongylus axei, Oxyuris equi, Triodontophorus serratus, Strongyloides westeri, Strongylus edentatus, Habronema muscae, Parascaris equorum, Probstmayria vivipara, Strongylus vulgaris, Gasterophilus nasalis, Anoplocephala magna and Anoplocephala perfoliata. In the present study, if the species Probstmayria vivipara was not considered in the prevalence, the frequency of Cyathostominae was equivalent to 94.85%. The results obtained in this study allowed us to detect and identify different species of helminths in horses, and confirmed the high incidence of nematodes belonging to the subfamily Cyathostominae in the center-west region of Minas Gerais.

In vivo effect of diflubenzuron, administered via mineral salt supplementation, against Haematobia irritans and Rhipicephalus microplus parasitizing cattle / Efeito in vivo do diflubenzuron, administrado via sal mineral, contra Haematobia irritans e Rhipicephalus microplus parasitando bovinos

Abstract This study involved two field trials with the aim of evaluating the efficacy of diflubenzuron, via mineral supplementation, against Haematobia irritans parasitizing cattle. Concomitantly with the main trial, a stall test was conducted to ascertain the effects of a different formulation with the same active ingredient against Rhipicephalus microplus, along with the action of diflubenzuron on the reproductive parameters of R. microplusfemales that had naturally detached from cattle. Against H. irritans, it was observed that the efficacy indexes fordiflubenzuron were low (≤ 31.3% or 44.6%) or null (0.0%) throughout the study. The anti- R. microplus efficacy of diflubenzuron, at weekly intervals, ranged from 0.0 to 13.7% over the entire experimental period. Null efficacy (0.0%) was registered for diflubenzuron in relation to the reproductive parameters of R. microplusfemales that had naturally detached from cattle. The different diflubenzuron formulations, administered via mineral salt supplementation, did not show satisfactory efficacy indexes against H. irritans and R. microplus parasitizing cattle, within the experimental design of the present study. In addition, this agent did not present any deleterious effects on the reproductive parameters of R. microplus females.

Resumo O objetivo deste estudo foi avaliar a eficácia do diflubenzuron, administrado via suplementação mineral, contra Haematobia irritans parasitando bovinos, em dois testes à campo. Concomitantemente, foi realizado testes em estábulo para determinar os efeitos de uma formulação diferente, com o mesmo princípio ativo, contra Rhipicephalus microplus , bem como a ação do diflubenzuron nos parâmetros reprodutivos de fêmeas de R. microplus recolhidas após desprendimento natural do hospedeiro bovino. Contra H. irritans, foi observado que foram baixos (≤ 31,3% ou 44,6%) ou nulos (0,0%) os índices de eficácia do diflubenzuron. A eficácia anti-R. microplus do diflubenzuron, observada em intervalos semanais, variaram de 0,0% a 13,7% durante todo o período experimental. Com relação aos parâmetros reprodutivos das fêmeas de R. microplus recolhidas, foi observada eficácia nula (0,0%) para o diflubenzuron. Conclui-se que as diferentes formulações administradas via sal mineral no atual estudo, contra H. irritans e R. microplus parasitando bovinos, não apresentaram eficácia satisfatória. Este agente também não mostrou efeito deletério sobre os parâmetros reprodutivos de fêmeas de R. microplus.

First outbreak and subsequent cases of Trypanosoma vivax in the state of Goiás, Brazil / Primeiro surto e casos subsequentes de Trypanosoma vivax no Estado de Goiás, Brasil

Abstract Trypanosomiasis caused by Trypanosoma vivax has increased the reports in Brazil in the last decade. An outbreak is herein first reported in the state of Goiás, from May 2016 to January 2017. The outbreak start occurred in the city of Ipameri (Goiás) after the introduction of 18 auctioned cows from the state of Minas Gerais. Direct parasitological test (blood smears) and polymerase chain reactions targeting the catL genes diagnosed T. vivax infection. Fifty six cows from a herd of 161 were infected; 12 died during the outbreak and 44 animals persistently positive (by blood smears) even after chemical treatment were discarded. After this first case, five other cases were detected in state of Goiás. The spread of this disease can be linked to the commercialization of animals carrying T. vivax, allied to the iatrogenic transmission practice, using a single needle and syringe for all cows, during oxytocin administration before each milking.

Resumo Tripanossomíase causada por Trypanosoma vivax tem sido reportada em várias regiões do Brasil na última década. Um surto é aqui reportado no Estado de Goiás, de maio de 2016 a janeiro de 2017. O início do referido surto ocorreu na cidade de Ipameri (Goiás) depois da introdução de 18 vacas Girolando, provenientes do Estado de Minas Gerais. Pelo exame parasitológico direto (esfregaço sanguíneo) e pela reação em cadeia pela polimerase, identificou-se a infecção por T. vivax nos animais. Cinquenta e uma vacas de um rebanho de 161 foram infectadas; 12 morreram durante o surto e 44 animais permaneceram positivos (pelo esfregaço sanguíneo) mesmo recebendo tratamento químico (diminazene), e foram descartadas. Após esse primeiro caso, foram detectados outros cinco casos no Estado de Goiás. A disseminação dessa doença pode estar ligada à comercialização de animais portadores de T. vivax, aliada à prática de transmissão iatrogênica, utilizando-se uma única agulha e seringa para, todas as vacas, durante a administração da oxitocina antes de cada ordenha.

Seroprevalence of and risk factors for Toxoplasma gondii in sheep raised in the Jaboticabal microregion, São Paulo State, Brazil.

Seroprevalence of and risk factors for toxoplasmosis in sheep from different properties in the Jaboticabal microregion, São Paulo State, Brazil were determined. Antibodies to Toxoplasma gondii were found in sera of 52.0% of 488 sheep tested by indirect fluorescent antibody test (IFAT > or =64). T. gondii seropositivity in sheep was significantly associated with gender of the sheep, pasturing system, contact with cats, and the use of mineral supplements and the type of feed.

[Occurrence de Leishmania spp. in domestic cats from Araçatuba, SP]. / Ocorrência de Leishmania spp. em felinos do município de Araçatuba, SP.

This study had the purpose to compare the occurrence of Leishmania spp. in felines through two methods (cytological and serological), as well as to associate the occurrence of this protozoan with the sex, age and breed variables. Serum samples from 283 domestic felines were processed by means of Indirect Immunofluorescence Reaction (IIR), and the direct parasitological test for linfonodes was also carried out in order to verify positivity for Leishmania spp. Occurrence of 0.7% (2/283) was observed in the tested felines by means of linfonode imprinting and no animal showed title of antibodies for Leishmania spp. The two positive females were mongrel, a young female and an adult female feline. From the obtained results, no statistically significant difference was observed as regards the sex, breed and age variables in this research (p > 0.05). Occurrence of Leishmania spp. in the cats of this study was low. Such low incidence suggests that these hosts has no epidemiological relevance in the study area.

Occurrences of Oestrus ovis parasitism in necropsied sheep in the Umuarama microregion, Paraná, Brazil / Ocorrência de parasitismo por Oestrus ovis em ovinos necropsiados da microrregião de Umuarama - Paraná, Brasil

Between January 2007 and September 2013, 71 sheep belonging to 12 farms in the Umuarama microregion, State of Paraná, were evaluated regarding presence of Oestrus ovis larvae, during necropsies. The farms from which these animals originated were visited and the owners and employees were interviewed. Occurrences of O. ovis parasitism in sheep were diagnosed for the first time on this microregion. Of the 71 animals, 12 (16.9%) were parasitized by O. ovis, with mean intensity of 2.25 larvae per infested head (1 to 8 larvae/infested head). There was a high correlation (0.81, p=0.0346) between the number of larvae and the macroscopic lesions observed in these animals nasal cavities, such that sheep with more than 3 larvae may contain mucupurulent secretions or epistaxis. From the interviews conducted, it was found that all the farm owners were applying chemical parasite control methods (helminths and/or O. ovis), administered to all animals in the herds every 30 days (91.6% of the producers), using derivatives of macrocyclic lactones and/or benzimidazoles/imidazothiazoles. Further studies need to be conducted in this particular region, in an attempt to elucidate the prevalence of O. ovis parasitism in herds.

De janeiro de 2007 a setembro de 2013, foram avaliados, durante a necropsia, 71 ovinos pertencentes a 12 propriedades rurais da microrregião de Umuarama, Paraná, Brasil, quanto à presença de larvas de Oestrus ovis. Entre outubro e dezembro de 2013, as 12 propriedades de onde os animais eram provenientes foram visitadas, e os proprietários e funcionários foram entrevistados. A ocorrência do parasitismo por O. ovis em ovinos foi constatada pela primeira vez em propriedades rurais da microrregião de Umuarama, Estado do Paraná. Dos 71 animais, 12 (16,9%) estavam parasitados por O. ovis, com intensidade média de parasitismo de 2,25 larvas por cabeça infestada (1 a 8 larvas). Foi possível verificar correlação elevada (0,81, p=0,0346) apenas entre o número de larvas versus lesões macroscópicas observadas na cavidade nasal desses animais, de modo que ovinos com mais de 3 larvas continham secreção mucopurulenta ou epistaxe na cavidade. Quando da entrevista constatou-se que todos os proprietários fazem controle químico contra parasitas (helmintos e/ou O. ovis) e esse. controle é feito a cada 30 dias por 91,6% dos produtores, que utilizam derivados de lactonas macrocíclicas e/ou benzimidazóis/imidatiazóis. Futuros estudos ainda precisam ser realizados nesta região, na tentativa de elucidar a prevalência de parasitismo por O. ovis nos rebanhos.

Resistência de Haemonchus placei, Cooperia punctata e Oesophagostomum radiatum à ivermectina pour-on a 500mcgkg-1 em rebanhos bovinos no Brasil / Haemonchus placei, Cooperia punctata and Oesophagostomum radiatum resistant to ivermectin pour-on 500mcgkg-1 in cattle from Brazil

O amplo espectro de ação dos endectocidas e a praticidade de aplicação das suas formulações pour-on são fatores que têm estimulado uma maior frequência de utilização destes produtos na criação de bovinos. Neste estudo, avaliou-se a eficácia anti-helmíntica da ivermectina, administrada via pour-on, 500mcgkg-1, contra nematódeos de bovinos provenientes de diferentes rebanhos. Foram adquiridos 12 bezerros de cada um dos quatro rebanhos selecionados. Todos os 48 bezerros utilizados apresentavam médias de ovos por grama de fezes (OPG) maiores que 500, considerando-se três contagens consecutivas. Na sequencia, os animais de cada rebanho foram divididos em dois grupos de seis bovinos cada, sendo um tratado com ivermectina 500mcgkg-1 via pour-on e outro mantido como controle. Quatorze dias depois do tratamento, os bovinos foram submetidos à eutanásia para contagem de endoparasitas. A ivermectina demonstrou resultados nulos de eficácia contra H. placei nos quatro rebanhos. Contra C. punctata, tal formulação teve eficácia nula nos rebanhos provenientes de Jaboticabal,SP, e de Formiga,MG, e eficácias de 75,8% e 58,4% nos rebanhos provenientes de São José do Rio Pardo,SP, e de São Sebastião do Paraíso,MG, respectivamente. Valores de eficácia de 94,2% (Jaboticabal), 0,0% (São José do Rio Pardo), 94,2% (Formiga) e 39,2% (São Sebastião do Paraíso) foram detectados contra O. radiatum. Com base nos resultados encontrados, pode-se concluir que as quatro populações de Haemonchus placei e de Cooperia punctata avaliadas foram resistentes à ivermectina, administrada via pour-on, 500mcgkg-1. Foram observadas cepas de Oesophagostomum radiatum resistentes à ivermectina em dois dos quatro rebanhos testados.

The broad spectrum of endectocides and the easy use mode of their pour-on formulations are factors that have stimulated a higher frequency of use these drugs in cattle. In this study was evaluated the efficacy of ivermectin pour-on using the dose of 500mcgkg-1, against nematodes in naturally infected cattle from different herds. Twelve calves were brought from each of the four farms selected. All the 48 calves used showed mean of eggs per gram of feces (EPG) greater than 500 considering three consecutive counts. Subsequently, animals from each herd were divided into two groups of six animals each, one treated pour-on with ivermectin 500mcgkg-1 and other kept as untreated control. Calves were euthanized 14 days after treatment for counting the endoparasites. Ivermectin showed null effect against H. placei in all the herds evaluated. The drug was also ineffective against C. punctata in the herds from Jaboticabal,SP and Formiga,MG, and reached efficacy of 75.8% and 58.4% in herds from São José do Rio Pardo,SP and São Sebastião do Paraíso,MG, respectively. Efficacies of 94.2% (Jaboticabal), 0.0% (São José do Rio Pardo), 94.2% (Formiga) and 39.2% (São Sebastião do Paraíso) were detectedagainst O. radiatum. Based on these results obtained on the present study, the four populations of Haemonchus placei and Cooperia punctata evaluated were resistant to ivermectin pour-on using a dose of 500mcgkg-1. Ivermectin-resistant strains of Oesophagostomum radiatum were found in two of the four herds evaluated.

Fauna helmintológica de ovinos provenientes da microrregião de Jaboticabal, estado de São Paulo, Brasil / Helminth fauna of sheep from the micro region of Jaboticabal, São Paulo State, Brazil

Avaliou-se a prevalência e a contagem parasitária das diferentes espécies de helmintos de ovinos provenientes da microrregião de Jaboticabal, região Noroeste de São Paulo. Para tanto, foram utilizados 66 animais naturalmente infectados, de quatro a 36 meses de idade, criados em regime extensivo. Os resultados necroscópicos revelaram a presença de sete gêneros e 12 espécies, com a seguinte prevalência e a média de parasitismo: Haemonchus contortus: 100,0% (2947,2); Trichostrongylus colubriformis: 90,9% (3048,8); Cooperia curticei: 56,0% (256,5); Oesophagostomum columbianum: 48,4% (36,0); Cooperia punctata: 30,3% (94,5); Trichostrongylus axei: 22,7% (26,5); Strongyloides papillosusi: 19,6% (83,0); Haemonchus contortus (L4): 7,5% (17,2); Cooperia pectinatai: 10,6% (12,9); Trichuris ovis: 10,6% (0,6); Cooperia spatulata 4,5% (0,3); Capillaria bovis: 4,5% (0,1). A carga parasitária média foi de 6.524,7 helmintos por animal. Haemonchus contortus (Adultos e L4) e Trichostrongylus colubriformis corresponderam a 45,4% e 46,7% da carga parasitária média total, respectivamente. Pode-se concluir que as duas espécies de helmintos mais abundantes e importantes da microrregião de Jaboticabal/São Paulo foram Trichostrongylus colubriformis e Haemonchus contortus, sendo que essas duas espécies perfizeram 92,1% da distribuição percentual dos helmintos recolhidos de todos os animais. Tais resultados demonstram a importância em se realizar um monitoramento das contagens de ovos por grama de fezes (OPG) dos rebanhos desta região, quando o método FAMACHA for empregado em uma determinada propriedade, uma vez que este método de controle, geralmente, não permite diagnosticar os danos/sinais clínicos desencadeados nos animais pelo T. colubriformis, em função de essa espécie não possuir hábito de hematofagismo sobre os hospedeiros.

This study evaluated the prevalence and counting parasitism of different species of helminths of sheep from the micro-region of Jaboticabal of São Paulo state. For this, 66 animals naturally infected, four to 36 months of age, raised in pasture, were selected. The results of necropsy revealed the presence of seven genera and 12 species with the following prevalence and mean count: Haemonchus contortus: 100.0% (2947.2); Trichostrongylus colubriformis: 90.9% (3048.8); Cooperia curticei: 56.0% (256.5); Oesophagostomum columbianum: 48.4% (36.0); Cooperia punctata: 30.3% (94.5); Trichostrongylus axei: 22.7% (26.5); Strongyloides papillosusi: 19.6% (83.0), Haemonchus contortus (L4): 7.5% (17.2), Cooperia pectinatai: 10.6% (12.9), Trichuris ovis: 10.6 % (0.6); Cooperia spatulata 4.5% (0.3); Capillaria bovis: 4.5% (0.1). The mean parasitism of helminthswas 6524.7 per animal. Haemonchus contortus (adults and L4) and Trichostrongylus colubriformis corresponded to 45.4% and 46.7% of the average worm burden totally, respectively. Based in the results obtained in this study, can be concluded that the two most abundant species of helminths and important, the micro-region of Jaboticabal are Trichostrongylus colubriformis and Haemonchus contortus, and these two species amounted to 92.1% of the distribution percentage of helminths collected from all animals. These results demonstrate the importance of conducting a counts of eggs per gram of feces (EPG) in the herds of this region when FAMACHA is used on a particular property, since this method control does not allow to diagnostic the damage/clinical signs in animals infected by T. colubriformis, because this specie does not have hematophagism habit on animals.

Effect of a spray formulation on the reproductive parameters of a susceptible population of Rhipicephalus (Boophilus) microplus / Efeitos de uma formulação pulverização sobre os parâmetros reproductivos de uma população susceptível de Rhipicephalus (Boophilus) microplus

The number of studies emphasizing the possible damage that acaricidal spray formulations can cause on engorged female ticks' reproductive parameters is small. The present study evaluated the deleterious effects of a spray formulation (dichlorvos 60% + chlorpyrifos 20%) on the reproductive parameters of a susceptible population of Rhipicephalus (B.) microplus females, using the Stall Test. The ticks were allocated randomly to treatments according to the mean numbers of females detached from each cow on days -3, -2 and -1 and the cattle pen location. The numbers of engorged female ticks that naturally detached from the cattle were counted daily from day 1 to day 30. For each group, 20 detached engorged female ticks or the available number collected daily were evaluated regarding reproductive parameters. Associations of organophosphates demonstrated elevated acaricidal efficacy, as well as deleterious effects on the reproductive parameters of R. (B.) microplus females. The engorged female weight (days 1 to 7), weight of egg masses (days 5 to 10) and larval hatching percentage (days 5 to 19) were decreased (P ≤ 0.05). It is possible that a formulation can lead to deleterious effects on R. (B.) microplus females when the tick population analyzed shows elevated sensitivity towards a particular formulation. However, further studies need to be conducted.

É relativamente pequeno o número de estudos que enfatiza os danos que uma formulação acaricida spray pode desencadear sobre os parâmetros reprodutivos das teleóginas. O presente estudo teve como objetivo avaliar os efeitos deletérios de uma formulação spray comercial (dichlorvos 60% + Clorpirifós 20%), sobre os parâmetros reprodutivos de uma população susceptível de R. (B.) microplus, desprendidas de bovinos experimentalmente infestados, utilizandose o teste de estábulo. Os animais foram alocados aos grupos de tratamentos de acordo com a contagem média de fêmeas desprendidas dos bovinos nos dias -3, -2 e -1. O número de teleóginas desprendidas foi quantificado do dia 1 ao 30. Para cada grupo, diariamente 20 fêmeas, ou a quantidade disponível, foram selecionadas e submetidas à avaliação dos parâmetros reprodutivos. A associação de organofosforados demonstrou elevada eficácia acaricida e também apresentou efeitos deletérios sob os parâmetros reprodutivos de Rhipicephalus (B.) microplus, diminuindo (P≤0,05) o peso das teleóginas (dos dias 1 ao 7), o peso da massa de ovos (dos dias 5 ao 10) e a eclodibilidade das larvas (dos dias 5 ao 19). Talvez uma formulação pode apresentar efeitos deletérios sobre os parâmetros reprodutivos de fêmeas de R. (B.) microplus, quando existe um elevado grau de sensibilidade dessa cepa de carrapato a um determinado composto. De qualquer maneira, futuros estudos devem ser realizados.

Endoparasites of horses from the Formiga city, located in center-west region of the state of Minas Gerais, Brazil / Endoparasitas de equinos provenientes do município de Formiga, localizado na região Centro-oeste do estado de Minas Gerais, Brasil

With the aim of studying the endoparasite fauna of horses from the Formiga city, located in center-west region of the state of Minas Gerais, 25 animals that were naturally infected with helminths were evaluated. By means of parasitological necropsies, different endoparasites were found. The subfamily Cyathostominae presented the highest incidence, followed by Trichostrongylus axei, Oxyuris equi, Triodontophorus serratus, Strongyloides westeri, Strongylus edentatus, Habronema muscae, Parascaris equorum, Probstmayria vivipara, Strongylus vulgaris, Gasterophilus nasalis, Anoplocephala magna and Anoplocephala perfoliata. In the present study, if the species Probstmayria vivipara was not considered in the prevalence, the frequency of Cyathostominae was equivalent to 94.85%. The results obtained in this study allowed us to detect and identify different species of helminths in horses, and confirmed the high incidence of nematodes belonging to the subfamily Cyathostominae in the center-west region of Minas Gerais.

Com o objetivo de estudar a fauna de endoparasitas de equinos da Região Centro-Oeste do Estado de Minas Gerais, 25 animais naturalmente infectados por helmintos foram avaliados. Por meio de necropsias parasitológicas, diferentes endoparasitas foram identificados. A sub - família Cyathostominae apresentou maior incidência, seguido por Trichostrongylus axei, Oxyuris equi, Triodontophorus serratus, Strongyloides westeri, Strongylus edentatus, Habronema muscae, Parascaris equorum, Probstmayria vivipara, Strongylus vulgaris, Gasterophilus nasalis, Anoplocephala magna e Anoplocephala perfoliata. No presente estudo, se não for considerada a espécie Probstmayria vivipara na prevalência, a frequência de Cyathostominae é equivalente a 94,85%. Os resultados obtidos neste estudo, permitiu detectar e identificar diferentes espécies de helmintos em equinos, bem como confirmar a elevada incidência de nematódeos pertencentes à sub-família Cyathostominae na Região Centro-Oeste de Minas Gerais.