Felipe Lamberti Pivoto

Serological status of mares in parturition and the levels of antibodies (IgG) against protozoan family Sarcocystidae from their pre colostral foals

Protozoa from the family Sarcocystidae are agents of reproductive and neurological disorders in horses. The transmission of these protozoa may occur via horizontal or vertical means, and the frequency and potential of the later is not fully elucidated in horses. Thus, the aim of study was to correlation levels of antibodies in mares with pre colostral foals seropositive and assess the level and distribution of antibodies against Neospora spp., Sarcocystis neurona and Toxoplasma gondii, in mares and pre colostral foals at the parturition. The blood samples were collected from mares immediately after parturition and from newborns before the ingestion of colostrum, and sera were analyzed for the presence of IgG by ELISA. It was found that 21.5%, 33.7% and 27.6% of mares were seropositive for Neospora spp., S. neurona and T. gondii, respectively; foals had antibodies at a rate of 8.3%, 6.6% and 6.6% for Neospora spp., S. neurona and T. gondii, respectively. Additionally, paired samples from mares and pre-colostral foals revealed an overall negative correlation between the serum reactivity against these three parasites and suggested that seronegative mares, or those with low to intermediate antibody levels, have a higher risk of giving birth to seropositive foals.

The importance of vertical transmission of Neospora sp. in naturally infected horses

Neospora spp. is a intracellular protozoan phylogenetically closely related to Toxoplasma gondii and Sarcocystis neurona, and it can infect horses leading to the development of reproductive or neurological diseases. We determined the presence of antibodies to Neospora sp. in mares at their parturition time and determine the frequency of vertical transmission in healthy foals to verify the importance of transplacental transmission. The samples were analyzed by indirect immunofluorescence antibody test, showing that seroprevalence in mares is higher than in foals and seropositive mares are likely to transmit the neosporosis to their offspring. This shows that endogenous challenge occurs in horses, and it suggests that this protozoan can be disseminated by means of transplacental transmission in horse species.

Combinação de drogas antiparasitárias como uma alternativa para o controle de nematódeos gastrintestinais multirresistentes em ovinos

This study was conducted to find effective anthelmintic treatments on a multi-resistant population of gastrointestinal nematodes of sheep, which was found resisting to all the classes of nematicidal drugs available in the Brazilian market. We took as a starting point the data obtained in a previous study performed in the targeted flock, in which were tested conventional treatments. Thus, using the calculated efficacy of the drugs (tested previously) for the genera of nematodes found in the flock, we selected drugs which, combined or used in higher doses, could improve the efficacy of the treatments. We evaluated the anthelmintic action of each treatment using the percentage of reduction of eggs in the feces, along with larvae cultures. A combination of moxidectin 1% + disophenol 20% showed 99% of efficacy, and combinations of moxidectin 1% + trichlorphon 10% and moxidectin 1% + levamisole phosphate 22.3% showed efficacy over 90%. Combinations of drugs, with different mechanisms of action, can provide effective anthelmintic treatments on multidrug-resistant populations of gastrointestinal nematodes of sheep.

Rhipicephalus (Boophilus) microplus in the western-central region of Rio Grande do Sul, Brazil: multiresistant tick

The aim of the present study was to assess the acaricide resistance of tick populations in the western-central region of Rio Grande do Sul (Brazil), which has not previously been reported. Fifty-four cattle farms were visited and specimens of Rhipicephalus (Boophilus) microplus were collected and subjected to the adult immersion test, using nine commercial acaricides in the amidine, pyrethroid and organophosphate groups. Climatic data, including monthly precipitation, were recorded. The results from the present study demonstrated that seven of the acaricides analyzed presented mean efficacy values of less than 95%, with large differences among the products tested. Nine of them exhibited satisfactory and unsatisfactory acaricide results on at least one farm. In conclusion, the farms located in the western-central region of Rio Grande do Sul, Brazil, exhibited populations of R. (Boophilus) microplus with variable degrees of susceptibility to different acaricides, thus suggesting that resistance to the active compounds exists. It is suggested that treatment protocols should be implemented at the beginning of winter and summer, using the acaricides that showed efficacy in the adult immersion test.

Ocorrência de parasitos gastrointestinais e fatores de risco de parasitismo em gatos domésticos urbanos de Santa Maria, RS, Brasil

This study verified the gastrointestinal parasites occurrence in household cats in Santa Maria, RS, Brasil from March to June, 2011. In addition, the risk factors associated with gastrointestinal parasites infection were evaluated. One hundred ninety -one felines fecal samples were submitted to parasitological examination, as well as to an epidemiological questionnaire about the management and the animal habits, which was applied to the owners. Fecal samples were positive for one or more gastrointestinal parasites (47.1% - 90/191). Occurrence of mono-infection was 33.5% (64/191) and multi-infection 13.6% (26/191). Toxocara spp. (18.8%) and Giardia spp. (4.2%) were the main parasites found in mono-infection. The main association of parasites detected included: Ancylostoma spp. + Toxocara spp. (3.1%) and Cystoisospora spp. + Cryptosporidium spp. + Giardia spp. + Toxoplasma spp. + Toxocara spp. (1.5%). Epidemiological data were submitted to chi-square, Fisher and odds ratio tests, as well as analyzed the relationship between the epidemiological factors and the presence of gastrointestinal parasites (P>0.05). The main risk factors identified were: the scholar level of owners and frequency of antiparasitic treatments, which showed a direct influence on the occurrence of gastrointestinal parasites. The data contribute to the understanding of the epidemiology of gastrointestinal parasites and could aid veterinarians and owners in developing of antiparasitic strategies for domestic cats.

Efeito do óleo de eucalipto (Corymbia citriodora) no controle do carrapato bovino

This research was aimed at evaluating in vitro and in vivo effects of eucalyptus (Corymbia citriodora) oil on cattle ticks (Rhipicephalus (Boophilus) microplus). Negative control group and eight concentrations of eucalyptus oil (0.5; 1; 2; 5; 10; 20; 50; 100%), were used on in vitro trials with engorged female ticks. The efficacy of control ticks was 0; 30.5; 75.5; 91; 100; 100; 100; 100 and 100%, respectively. At the in vivo trial eighteen Holstein cows were allocated to three groups (negative control, eucalyptus oil at 3.5% - level estimated by regression analysis, accounting for 95% efficacy of control ticks on in vitro trial and amitraz at 0.025%). Engorged female ticks were counted before (mean of days -3, -2, -1) and after treatment (1, 2, 3, 5, 7, 10, 14, 21 days). The efficacy control tick was 0; 96.4 and 69%, respectively, at 21 days after treatment. On the 1st and 2nd milked after treatments, physiologic variables were evaluate and milk samples were collected to evaluate organoleptic properties in milk and yoghurt (negative control x phytotherapic treatment). Similar results were found with sensorial acceptance test of milk and physiologic variables.

Effect of zinc supplementation on ecto-adenosine deaminase activity in lambs infected by Haemonchus contortus: Highlights on acute phase of disease

Haemonchus contortus (order Strongylida) is a common parasitic nematode infecting small ruminants and causing significant economic losses worldwide. It induces innate and adaptive immune responses, which are essential for the clearance of this nematode from the host. Ecto-adenosine deaminase (E-ADA) is an enzyme that plays an important role in the immune system, while Zinc (Zn) has been found playing a critical role in E-ADA catalysis. Therefore, the aim of this study was to assess the effect of Zn supplementation on E-ADA activity in serum of lambs experimentally infected with H.contortus. To reach this purpose 28 male lambs (in average 25 kg) were used. The animals were divided into four groups: A and B composed of healthy animals (uninfected); C and D, infected with H.contortus. Groups B and D were supplemented with Zn Edetate, subcutaneously with 3 mg kg of live weight, on days 11 and 25 post-infection (PI). Blood and fecal samples were collected on the days 11, 25 and 39 PI, in order to assess hematocrit, seric E-ADA, and eggs per gram (EPG) counting, respectively. The animals of groups C and D showed severe hematocrit reduction (days 25 and 39 PI) and were EPG positive (days 11, 25 and 39 PI). On day 41 PI, three animals each group were subjected to necropsy. This procedure showed that animals of groups A and B did not have helminths in abomasum and intestines, while H.contortus were observed in groups C (5782.5 ± 810.9) and D (6185.0 ± 150.0). Infected and untreated animals (group C) showed a reduction in E-ADA activity, but this was not observed when the animals were supplemented with Zn (Group D). Therefore, based on our results, it was possible to observe that Zn supplementation exercised a positive effect on E-ADA activity in lambs infected with H.contortus, and did not allow a reduction in E-ADA activity, as occurred in the group infected and without supplementation. However, Zn supplementation was not able to prevent the worm burden.

Copper and selenium: Auxiliary measure to control infection by Haemonchus contortus in lambs

The aim of this study was to evaluate the effects of selenium and copper on oxidative stress and its performance in lambs experimentally infected with Haemonchus contortus. Twenty-eight five-months old lambs were experimentally infected by the oral route with 5000 third-stage infective larvae and allocated into four groups, i.e., untreated animals, animals treated intramuscularly with sodium selenite (0.2 mg kg(-1)), animals treated subcutaneously with copper (3.5 mg kg(-1)), and animals treated with sodium selenite (IM; 0.2 mg kg(-1)) and copper (SC; 3.5 mg kg(-1)). These animals received oat hay (Avena sativa) and commercial concentrate, totaling 15% of crude protein, 30% being derived from oat hay and 70% of the concentrate. Lipid peroxidation, antioxidant enzymes, eggs per gram of feces (EPG) and body weight were assessed on the day of infection and after 20, 40, 60 and 80 days post-infection. The number of H. contortus adults was assessed at the end of the experiment. The selenium associated or not with copper reduced the effects of oxidative stress caused by infection. The groups supplemented with copper had increased body weight, and the combination of these two minerals reduced the EPG and number of H. contortus adults in lambs. The use of selenium associated with copper may help the control of infection by H. contortus.

Oxidative stress by Haemonchus contortus in lambs: Influence of treatment with zinc edetate

The aim of the present study was to assess the effects of zinc edetate on the oxidative stress of lambs infected by Haemonchus contortus. Twenty-four lambs were allocated into four groups: Group I--uninfected animals; Group II--uninfected animals treated subcutaneously with zinc edetate; Group III--animals infected by H. contortus and Group IV--animals infected and treated. The oxidative stress index (OSI) and the eggs per gram of feces (EPG) were assessed after 10, 17, 24, 31 and 38 days post-infection. Based on the EPG and the quantity of adult H. contortus, the infection did not differ between groups III and IV. Zinc edetate reduced the OSI in Group IV in relation to Group I after 24 days post-infection, and in relation to group III after 31 days post-infection. Treatment with zinc edetate could help reduce the oxidative stress induced by H. contortus in lambs.

Ação acaricida in vitro de Tropaeolum majus sob teleóginas de Rhipicephalus (Boophilus) microplus

The aim of this study was to evaluate the in vitro acaricide effect of aqueous and ethanolic extracts of Tropaeolum majus on Rhipicephalus (Boophilus) microplus engorged females. Extracts from the aerial parts (stems and leaves) and from the flowers were tested at a final concentration of 2%. The Rhipicephalus (Boophilus) microplus engorged females were collected in farms in two municipalities (Sao Francisco de Assis and Sao Pedro do Sul), in Rio Grande do Sul state, Brazil. An efficacy of 99,1% was found using extract of aerial parts in ethanol at 70%. This is the first report of acaricidal effect of Tropaeolum majus.