Scielo RSS <![CDATA[Onderstepoort Journal of Veterinary Research]]> http://www.scielo.org.za/rss.php?pid=0030-246520090002&lang=pt vol. 76 num. 2 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Seroprevalence of <i>Cryptosporidium parvum </i>infection of dairy cows in three northern provinces of Thailand determined by enzyme-linked immunosorbent assay using recombinant antigen CpP23</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0030-24652009000200001&lng=pt&nrm=iso&tlng=pt Cryptosporidium parvum is the most frequent parasitic agent that causes diarrhoea in AIDS patients in Thailand. Cryptosporidiosis outbreaks in humans may be attributed to contamination of their drinking water from infected dairy pastures. A 23-kDa glycoprotein of C. parvum (CpP23) is a sporozoite surface protein that is geographically conserved among C. parvum isolates. This glycoprotein is a potentially useful candidate antigen for the diagnosis of cryptosporidiosis by enzyme-linked immunosorbent assay. Therefore, we investigated the seroprevalence of C. parvum infection in dairy cows in northern Thailand using an ELISA based on recombinant CpP23 antigen. Sera were randomly collected from 642 dairy cows of 42 small-holder farmers, which had the top three highest number of the dairy cows' population in Northern Thailand, that included Chiang Mai, Chiang Rai and Lumpang provinces. The overall seroprevalence of the infection was 4.4 %, and the seropositive rates for the three provinces were 3.3 % in Chiang Mai, 5.1 % in Chiang Rai and 3 % in Lumpang. These results suggest that cattle could play a role in zoonotic cryptosporidiosis in Thailand. <![CDATA[<b>Ticks collected from birds in the northern provinces of South Africa, 2004-2006</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0030-24652009000200002&lng=pt&nrm=iso&tlng=pt Approximately 3 000 birds, mainly passerines, caught in mist nets in the northern provinces of South Africa, were examined for ticks. A total of 178 ticks, belonging to 14 species, were recovered from 83 birds of 43 different species. Hyalomma rufipes was the most numerous tick, with 26 larvae and 109 nymphs collected, followed by Amblyomma marmoreum, with 13 larvae and two nymphs. Despite the study being conducted within the distribution range of Amblyomma hebraeum, it was not seen on any passerines, whereas three larger species were infested. The potential for small birds to spread ticks with their associated tick-borne pathogens is discussed. <![CDATA[<b>Ticks (Acari: Ixodidae) infesting camels <i>(Camelus dromedarius) </i>in Northern Sudan</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0030-24652009000200003&lng=pt&nrm=iso&tlng=pt Monthly total body tick collections from 13-20 camels were conducted for 2 consecutive years (2000-2001) in Northern Sudan. Tick populations were correlated with locality, season, predeliction site, sex and coat colour. Hyalomma dromedarii was found to be the predominant (89 %) tick species infesting the camels. Other tick species found in very low numbers were Hyalomma impeltatum (7.7 %), Hyalomma anatolicum anatolicum (3.3 %), Hyalomma truncatum (0.29 %), Hyalomma marginatum rufipes (0.25 %), Rhipicephalus praetextatus (0.30 %) and Rhipicephalus sanguineus group (0.09 %). Nymphs of the genus Hyalomma were collected in significant numbers. Adult ticks significantly preferred to attach to the lower parts of the camel's body for feeding while the nymphs preferred the back of the animal. Female camels harboured more ticks than males while higher infestations were recorded on camels with a grey coat colour compared to those with a brown coat colour. Ticks were found on camels throughout the year and increased in numbers during March to October with a peak in September. <![CDATA[<b>Report on some monogenean and clinostomid infestations of freshwater fish and waterbird hosts in Middle Letaba Dam, Limpopo Province, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0030-24652009000200004&lng=pt&nrm=iso&tlng=pt This report deals with the results of a parasitological study done as part of a post-impoundment ecological study of Middle Letaba Dam, Limpopo Province, South Africa. It involved a seasonal survey protocol with particular attention to the diversity and prevalence of the parasitic fauna of the indigenous fish community of the dam and the role of selected fish-eating birds in the life cycle and distribution of fish helminths. The potential species composition of fish of the dam is provided. Monogenean and clinostomatid parasites encountered are listed and infestation statistics of fish and fish-eating bird hosts are presented. The results of this study also provide information on new distribution and host records of the encountered monogeneans. <![CDATA[<b>The comparative prevalence of five ixodid tick species infesting cattle and goats in Maputo Province, Mozambique</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0030-24652009000200005&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Molasses as a possible cause of an "endocrine disruptive syndrome" in calves</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0030-24652009000200006&lng=pt&nrm=iso&tlng=pt During the mid 1990s a potentially serious, chronic syndrome was reported in well-managed beef and dairy herds from unrelated parts of South Africa. Farmers reported that it manifested as various combinations of decreased production, decreased weaning masses, apparent immune breakdown in previously immunocompetent animals, increased reproductive disorders, various mineral imbalances in non-deficient areas and goitre, noticeable as enlarged thyroid glands. The farmers associated this syndrome with certain batches of sugar cane molasses and molasses-based products. The syndrome was reminiscent of an "endocrine disruptive syndrome". The objective of this study was to evaluate the suspected endocrine disruptive effect of molasses included in cattle feed. Using existing in vitro assays, four batches of molasses syrup were screened for possible inclusion in a calf feeding trial. Two batches were selected for the trial. Thirty-two, 4- to 6-week-old, weaned Holstein bull calves were included in the single phase, three treatment, parallel design experiment. In two of the groups of calves, two different batches of molasses were included in their rations respectively. The control group was fed a ration to which no molasses was added, but which was balanced for energy and mineral content. The mass gain of the calves was recorded over the 6-month study period. The calves were clinically examined every week and clinical pathology parameters, immune responses and endocrine effects were regularly evaluated. Even though endocrine disrupting effects were detected with the in vitro screening assays, these could not be reproduced in the calves in the experiment. The two batches of molasses utilized in the calf feeding trial did not induce major differences in any of the parameters measured, with the exception of a lower mass gain in one of the molasses-fed groups (Group 1), which tended towards significance. The results of the study indicate that the two batches of molasses had no endocrine disruptive or immunosuppressive effects in calves. <![CDATA[<b>Ecological parameters of <i>Lamproglena hoi </i>(Copepoda: Lernaeidae) infection on the Bushveld smallscale yellowfish, <i>Labeobarbus polylepis </i>(Boulenger, 1907)</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0030-24652009000200007&lng=pt&nrm=iso&tlng=pt This study describes the distribution and aspects of the ecology of Lamproglena hoi. Bushveld small-scale yellowfish, Labeobarbus polylepis (Boulenger, 1907) were collected during June 2006 from the Phongolo and Assegaai rivers, March 2005 and October 2006 from the Elands River, and January 2007 and June 2008 from the Komati River in Mpumalanga, South Africa and examined for the presence of parasites. Lamproglena hoi specimens were collected from the gill filaments of the host. Specimens were fixed with warm AFA (alcohol-formaldehyde-acetic acid) and preserved in 70 % ethanol. The identification of parasites took place in the laboratories of the University of Johannesburg. Twenty-five copepods (prevalence 21 %, mean intensity = 4.17, abundance = 0.86) were collected on 29 fish in the Phongolo River and 46 copepods (prevalence 40 %, mean intensity = 3.83, abundance = 1.53) were collected on 30 fish in the Assegaai River. One hundred and sixty eight copepods (prevalence 52 %, mean intensity = 12.92, abundance = 6.72) were collected on 25 fish in 2005, and 527 copepods (prevalence 95 %, mean intensity = 27.74, abundance = 26.35) were collected on 20 fish in the Elands River. One hundred and sixteen copepods (prevalence 75 %, mean intensity = 7.73, abundance = 5.80) were collected on 20 fish in 2007, and 273 copepods (prevalence 63 %, mean intensity = 16.06, abundance = 10.11) were collected on 27 fish in 2008 in the Komati River. Labeobarbus polylepis from these four rivers was found to have a relatively high L. hoi infection. Inseminated L. hoi females (immature) attach to the host in winter and their ovaries become conspicuous (mature). In spring fertilized eggs are stored in egg sacs hanging from the body (gravid), indicating that fertilized eggs start to hatch in spring and continued hatching into summer. Parasites prefer the median part of the second gill arch for attachment. No correlation exists between the number of parasites recorded on the gills and the sizes (total lengths) of yellowfish sampled. <![CDATA[<b>Tick infestation, and udder and teat damage in selected cattle herds of Matabeleland South, Zimbabwe</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0030-24652009000200008&lng=pt&nrm=iso&tlng=pt A cross-sectional survey was conducted to determine tick infestation, and udder and teat damage in 286 lactating cows and heifers at six properties in the smallholder and commercial sectors in Gwanda district of Matabeleland South Province, Zimbabwe. Eight tick species were identified: Amblyomma hebraeum, Hyalomma truncatum, Hyalomma marginatum rufipes, Rhipicephalus evertsi evertsi, Rhipicephalus (Boophilus) decoloratus, Rhipicephalus appendiculatus, Rhipicephalus zambeziensis and Rhipicephalus simus. Overall, 81.5 % of the cattle were tick infested; prevalence of tick-infested cattle was significantly higher on communal land (93.8 %) and recently claimed land (85.1 %) than on commercial farms. The mean tick load on infested cattle on communal land was significantly higher than in the other two sectors. Although 53 % of the sampled cattle had some degree of udder and teat damage, very few farmers (2.6 %) treated their cattle for these conditions. Udder damage was ca. two times and three times, respectively, more likely to occur in cattle on communal land compared to cattle on recently claimed land and commercial farms. The occurrence of R. appendiculatus and R. zambeziensis indicate that the cattle population in the study area is at high risk of a theileriosis outbreak, a tick-borne disease that has not been reported from this area. <![CDATA[<b><i>Curtisia dentata </i></b><b>(Cornaceae) leaf extracts and isolated compounds inhibit motility of parasitic and free-living nematodes</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0030-24652009000200009&lng=pt&nrm=iso&tlng=pt Haemonchus contortus and Trichostrongylus colubriformis are among the most important parasitic nematodes of small ruminants. Caenorhabditis elegans, a free-living nematode, is used as a model for evaluating anthelmintic activity of a variety of test substances. Extracts of several medicinal plants are useful in vitro and in vivo against nematode development. Extracts of Curtisia dentata, a South African medicinal plant, and compounds isolated from leaves of this plant were investigated for anthelmintic activity against T. colubriformis, H. contortus and C. elegans. The acetone and dichloromethane extracts were active against all nematodes at concentrations as low as 160 μg/ml. Betulinic acid and lupeol were active against the parasitic nematodes only at the high concentrations of 1 000 and 200 μg/ml, respectively. All compounds were effective against C. elegans with active concentrations as low as 8 μg/ml. Betulinic acid was less active than lupeol and ursolic acid against C. elegans. The acetone and dichloromethane extracts were also active against C. elegans with a concentration of 0.31 mg/ml resulting in almost 80 % inhibition of larval motility. The use of free-living nematodes may provide information on the activity of potential anthelmintics against parasitic nematodes. Extracts of various medicinal plant species may provide solutions to ill-health of small ruminants caused by parasitic nematodes in poor communities of southern Africa. <![CDATA[<b>Evaluation of a rapid immunodiagnostic test kit for detection of African lyssaviruses from brain material</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0030-24652009000200010&lng=pt&nrm=iso&tlng=pt A rapid immunodiagnostic test kit was evaluated against a selection of isolates of lyssavirus genotypes occurring in Africa. The test was carried out in parallel comparison with the fluorescent antibody test (FAT) and isolates representing previously established phylogenetic groups from each genotype were included. The specificity of the rapid immunodiagnostic test compared favourably with the FAT and was found to detect all representatives of genotypes 1, 2, 3 and 4 in brain samples of either field cases or suckling mouse brain inoculates.